PST05103 Pharmaceutical Microbiology

NTA Level 5 • Semester 1 • PST05103 Activation of Lymphocytes Pharmaceutical Microbiology • Source Session/Topic 47 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 47Activation of Lymphocytes Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Explain types and functions of lymphocytes Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |15 minutes |Presentation |Lymphocytes | |3 |20 minutes |Presentation |Major Histocompatibility Complex | |4 |40 minutes |Presentation |Activation of Lymphocytes | |6 |5 minutes |Presentation |Key Points | | 7|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Lymphocytes (15 minutes) • Lymphocytes are a type of white blood cell (leukocyte) that are of fundamental importance in the immune system • Lymphocytes determine the specificity of the immune response to infectious microorganisms and other foreign substances • In adult humans lymphocytes make up roughly 20 to 40 percent of the total number of white blood cells • Lymphocytes are found in the circulation and in central lymphoid organs and tissues where initial immune response occurs • There are two primary types of lymphocytes; o B lymphocytes and T lymphocytes, or B cells and T cells • Both types of lymphocytes originate from stem cells in the bone marrow and are initially similar in appearance • The B cells produce antibodies that are used to attack invading bacteria, viruses, and toxins • The T cells destroy the body's own cells that have themselves been taken over by viruses or become cancerous STEP 3: Major Histocompatibility Complex (20 minutes) • Major Histocompatibility Complex (MHC) is a group of genes that code for proteins found on the surfaces of cells that help the immune system recognize foreign substances. The genes are located on chromosome 6 in human beings • Each gene of MHC has an unusually large number of alleles therefore it is very rare for two persons to have the same set of MHC molecules (tissue types) • MHC proteins are found in all higher vertebrates. In human beings the complex is also called the human leukocyte antigen (HLA) system • There two classes of MHC, class I and class II • MHC Class I o Molecules of MH Class I are found on membranes of almost all cells o These help the immune system to recognize heathy cells from infected cells and pathogens • MHC Class II o In MHC class II molecules are restricted to macrophages and lymphocytes o This class help cells of the immune system to interact and communicate with one another • The MHC also contains genes that code for other proteins e.g. the complement proteins, cytokines and enzymes. These proteins are called Major Histocompatibility Class III molecules • MHC molecules are important components of the immune system because they allow T lymphocytes to detect cells, such as macrophages, that have ingested infectious microorganisms • When a macrophage engulfs a microorganism, it partially digests it and displays peptide fragments of the microbe on its surface, bound to MHC molecules • The T lymphocyte recognizes the foreign fragment attached to the MHC molecule and binds to it, stimulating an immune response • In uninfected healthy cells, the MHC molecule presents peptides from its own cell (self-peptides), to which T cells do not normally react STEP 4: Activation of Lymphocytes (40 minutes) • Activation of lymphocytes occurs o in the thymus to form T-cells or T-lymphocytes o in bone marrow to form B-cells or B-lymphocytes • Most lymphocytes are short-lived, with an average life span of a week to a few months • A few lymphocytes live for years, providing a pool of long-lived T and B cells o These cells account for immunologic “memory,” a more rapid, vigorous response when the same antigen enters the body • Activation process involves macrophages engulfing and digesting pathogens o Through receptor molecules on their surfaces, lymphocytes are able to bind antigens and help remove them from the body o Each lymphocyte bears receptors that bind to a specific antigen o The ability to respond to virtually any antigen comes from the enormous variety of lymphocyte populations that the body contains, each of them with a receptor capable of recognizing a unique antigen o When macrophages engulf and digest pathogens, they take the antigenic components of that pathogen and display them on their membrane as antigens by attaching them onto major histocompatibility complex class II (MHC class II) ▪ This is antigen presentation and the macrophages are antigen presenting cells (APCs) o T-lymphocytes such as inactivated helper T cells can now bind onto these antigen complexes by using special receptors of their own (T cell receptors that contain the glycoprotein CD4) o Once bound, they begin releasing various chemicals such as interleukin-1, which activates that helper T cell o The helper T cell can then detach and bind to B-lymphocytes that contain that same antigenic piece, which causes the two cells to begin releasing cytokines and lymphokines o This causes the cloning process in which the cells divide mitotically to form many identical clones o Some of these B-cell clones differentiate into plasma cells and memory B cells while other T-cell clones differentiate into cytotoxic T cells. o The plasma cells produce antibody molecules which are released into the blood and lymph o Antibodies then bind to the target antigen and initiate its neutralization or destruction o Antibody production continues for several days or months, until the antigen has been overcome

NTA Level 5 • Semester 1 • PST05103 Complement System Pharmaceutical Microbiology • Source Session/Topic 48 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 48 Complement System Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Describe complement system Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |20 minutes |Presentation |Characteristics of complement | | | | |system | |3 |25 minutes |Presentation |Biological effect of complement | | | | |system | |4 |30 minutes |Presentation |Regulation of compliment system | |5 |5 minutes |Presentation |Key Points | |6 |5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Characteristics of complement system(20minutes) • The complement system is a well regulated system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen's cell membrane • The complement system includes serum and membrane-bound proteins that participate in both innate and adaptive immunity • These proteins are highly regulated and interact through a series of proteolytic cascades • Complements are soluble proteins and glycoproteins mostly produced by hepatocytes. • More than 20 types of complements are present in serum, found circulating normally in human body in inactive forms (called as zymogens or proenzymes) • Complement activation is triggered by an antibody when it is bound to the antigen • It can also be triggered by some components of innate immunity • Thus the complement system works in both innate and acquired immunity • Complements are activated only during inflammatory reactions • During the inflammation, more amount of complements reaches to the interstitial area of the infected tissue through dilated blood vessels, which are then activated by proteolytic cleavage; this exposes the active site of the complements. • Complements are mainly denoted by the capital letter C with numbers; like, C1, C2, C3, and so on. Some have only alphabet, like, B, D. Some are simply represented by names, like, homologous restriction factor. • C1 has three sub-units; C1q, C1r and C1s • C2-C5 have two components, a and b • Larger subunits are denoted by b and the smaller are denoted by a (except C2a, which is larger than C2b) • • STEP 3:Biological effect (Functions) of the Complement system • (40 minutes) • Opsonization and phagocytosis o C3b, bound to immune complex or coated on the surface of pathogen, activate phagocytic cells o These proteins bind to specific receptors on the phagocytic cells to get engulfed. • Cell lysis o Membrane attack complex formed by C5b6789 components ruptures the microbial cell surface which kills the cell. • Chemotaxis o Complement fragments attract neutrophils and macrophages to the area where the antigen is present o These cell surfaces have receptors for complements, like C5a, C3a, thus, run towards the site of inflammation, i.e. chemotaxis. • Activation of mast cells and basophils and enhancement of inflammation (Anaphylatoxins) o The proteolytic complement fragments, C5a, C4a, and C3a induce acute inflammation by activating mast cells and neutrophils. All three peptides bind to mast cells and induce degranulation, with the release of vasoactive mediators such as histamine. These peptides are also called anaphylatoxins because the mast cell reactions they trigger are characteristic of anaphylaxis. Binding to specific complement receptors on cells of the immune system, they trigger specific cell functions, inflammation, and secretion of immunoregulatory molecules. • Production of antibodies o B cells have receptor for C3b. When C3b binds to B-cell, it secretes more antibodies o Thus C3b is also an antibody producing amplifiers which converts it into an effective defence mechanism to destroy invading microorganism. • Immune clearance o The complement system removes immune complexes from the circulation and deposits them in the spleen and liver o Thus it acts as anti-inflammatory function. Complement proteins promote the solubilization of these complexes and their clearance by phagocytes. • The complement activation occurs via three pathways; which are: o Classical pathway ▪ activated by antigen-antibody reaction o Alternative pathway ▪ activated on microbial cell surfaces o Mannose binding Lectin (MBL) pathway ▪ activated by a plasma lectin that binds to mannose residues on microbes. • The Classic Pathway o The classical pathway begins with the formation of antigen- antibody complex (immune complex) o When an antigen enters the body, the antibody (IgM/IgG) binds to it o This induces conformational changes in the Fc portion of the antibody which exposes a binding site for C1 protein o Hence, the antibody activates the complement system only when bound to an antigen. o C1 is a large, multimeric, protein complex composed of one molecule of C1q and two molecules each of C1r and C1s subunits o C1q binds to the antigen bound antibody (Fc portion). C1r and C1s are proteases which help to cleave C4 and C2 o The immune complex bound to C1 calls another protein C4 which is cleaved into C4a and C4b o C4a goes away whereas activated C4b attaches to the target surface near C1q o Now, C4b attracts C2 which is also cleaved into C2a and C2b. C2a binds C4b forming the C4b2a complex whereas C2b goes away o The active C4bC2a activates C3. The C4b2a complex is also known as C3 convertase as this converts C3 into an active form by separating C3a and C3b o One molecule of C4b2a can cleave a large number of C3 molecules. C3b binds to the microbial surface or to the convertase

NTA Level 5 • Semester 1 • PST05103 Immunological Preparations Pharmaceutical Microbiology • Source Session/Topic 49 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 49: Immunological Preparations Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • List characteristics of immunological preparations • List immunological preparations • Define vaccines and sera • Differentiate between vaccine and sera • List components of vaccines and sera • Classify vaccines and list their characteristics Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |20 minutes |Presentation |Immunological Preparations | |3 |15 minutes |Presentation |Vaccines and Sera | |4 |40 minutes |Presentation |Classification of Vaccines and | | | | |Sera | |5 |30 minutes |Presentation |Composition of Vaccines and Sera | |6 |5 minutes |Presentation |Key Points | | 7|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Immunological Preparations (20 minutes) • Immunological preparations o Immunological preparations are a group of pharmaceutical preparations with diverse origins but with a common pharmacological purpose of modifying the immune status of a recipient, either to provide immunity to infectious disease or to help in detection (diagnosis) of a disease o Types of immunological preparations ▪ Vaccines ▪ Immune sera ▪ In-vivo diagnostics ▪ Immunoglobulins • Characteristics of Immunological Preparations o They modify the immune system o They contain antigens or antibodies/immunoglobulins o They produce specific responses STEP 3: Vaccines and Immune sera (15 minutes) • Vaccine o Vaccine is a biological preparation that consists of either a whole organism (killed or live attenuated) or part of an organism introduced into an individual to induce adequate antibody production against the organism so that the individual is protected against infection caused by that particular organism o Vaccines contain antigens that stimulate the immune system of the recipient to produce T-cells or antibodies that attack and destroy the infectious agent • Immune Sera o Immune sera (singular serum) also known as antisera are amber- coloured, protein-rich liquid that separates out when blood coagulates o Blood serum of an animal is used to provide immunity to a pathogen or toxin by inoculation or used as a diagnostic agent o The sera contain antibodies against specific disease and used to provide passive immunity to that diseases. Sera do not stimulate production of antibodies o Immune sera are prepared by injecting repeated doses of an antigen into horse or other suitable animal o The animal is injected until high titre of antibodies are produced by the body of the animal o The animal must be in good health and free from infections o Blood is obtained from the animal and processed to produce serum • Human Immunoglobulins o Are preparations of immunoglobulins principally IgG subclasses that are present in human blood o They are derived from plasma of donated blood and from plasma obtained from plasmapheresis o Specific immunoglobulins are prepared from smaller pools of plasma obtained from individuals who have suffered recent infections or who have undergone recent immunization and who have high titre of a particular antibody ▪ Plasma containing antibodies against hepatitis B and HIV or any plasma capable of transmitting infections to recipient are excluded o The immunoglobulins are presented as freeze dried or liquid preparation at suitable concentration (10-20 times higher than that in the plasma) o Glycine may be added as a stabilizer and thiomersal as a preservative STEP 4: Classes of vaccines and Sera (40 minutes) • Vaccines can be classified into two broad groups; o Vaccines containing killed or inactivated pathogens o Vaccines containing live or attenuated pathogens • Vaccines containing live or attenuated pathogens o Live vaccines ▪ Live vaccines are made up of live bacteria, viruses, or other agents which when administered by appropriate route cause subclinical or mild infections ▪ In the course of such infection the antigenic components in the vaccine evoke an immune response which provide protection against the more serious natural disease o Attenuated vaccines ▪ Attenuated vaccines are vaccines containing pathogens manipulated in the laboratory to produce strain of the pathogen with reduced virulence • Attenuation can be attained by mutant strain polio virus, consecutive passage through an anima which is not a host of the pathogen e.g. small pox vaccine passage in calf and passage through a series of cultures e.g. rabies virus in human cell culture ▪ The attenuated organisms multiply in the host and provoke and immune response o Examples of live vaccines include Bacille Calmette-Guerin (BCG), oral polio vaccine, yellow fever vaccine, measles vaccine etc. o Advantages of live vaccines include; ▪ Single dose is often enough ▪ Produce strong immunity o Disadvantage of live vaccines ▪ The organism may cause full fledge infection • Vaccines containing killed or inactivated pathogens (Inactivated vaccines) o These vaccines do not replicate as the pathogens are killed or only their components are present in the vaccines o They require adjuvants to enhance immunogenicity o They are toxic and thus require multiple doses o Most viral vaccines are killed or inactivated o Killed vaccines ▪ Killed vaccines are suspensions of whole bacteria, viruses or other pathogenic agents that have been killed by heat or by disinfectants such as phenol or formaldehyde ▪ The killed organisms cannot replicate to cause infection ▪ Because all the components of the microorganisms are present in the vaccine, the vaccine may be toxic to the body ▪ Therefore, killed vaccines are usually divided into initial and booster doses give at regular intervals of

NTA Level 5 • Semester 1 • PST05103 Storage and Delivery of Vaccine Total Session Time: 60 minutes Pharmaceutical Microbiology • Source Session/Topic 50 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 50: Storage and Delivery of Vaccine Total Session Time: 60 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Define cold chain • List components of cold chain • List equipment for cold chain • Explain the procedure for arrangement of vaccines in the refrigerator • List tools for monitoring cold chain • Explain strategies for vaccine delivery • List factors affecting quality of vaccines Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 | 20 minutes|Presentation |The Pharmaceutical cold chain | |3 |10 minutes |Presentation |Components of a pharmaceutical | | | | |cold chain | |4 |50 minutes |Presentation |Cold Chain Equipment | |5 |25 minutes |Presentation |Quality and vaccine delivery | |6 |5 minutes |Presentation |Key Points | | 7|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Pharmaceutical Cold Chain (20 minutes) • Cold chain is the system of transporting and storing vaccines (or other temperature sensitive items) at recommended temperature from the point of manufacture to the point of use • Common temperature range for a cold chain in pharmaceutical industries is 2 to 8 °C • Cold chains are important because; o Vaccines are biological product which lose potency with time o They ensure that maximum benefits are obtained from immunization i.e. reduce wastage of vaccines o They ensure quality of vaccines is maintained in order to gain confidence of the public on immunization programmes o They ensure compliance with manufacturers’ recommendation STEP 3: Components of Pharmaceutical Cold Chain (10 minutes) • Components of the cold chain are; o Personnel ▪ Trained to run the cold chain ▪ They need to be dedicated people who appreciate the delicate nature and importance of delivering safe vaccines to save lives o Equipment ▪ There two main types of equipment • Equipment for transportation of vaccines • Equipment for storage of vaccines • The equipment must be maintained in good condition to ensure safety and quality of vaccines STEP 4: Cold Chain Equipment (50 minutes) • Different levels of the health care system need different equipment for transporting and storing vaccine and diluent at the correct temperature • Central and regional stores need cold rooms, freezers, refrigerators and cold boxes (for transportation) • District stores need freezers, refrigerators and cold boxes • Primary health facilities need refrigerators, cold boxes and vaccine carriers • Equipment for storage of vaccines o Walk-in cold rooms ▪ These are large specialized rooms (in the warehouse) in which low temperature is maintained for storage of large quantities of vaccines ▪ They are used at the regional level ▪ Maintains products at low temperatures for a duration of up to 3 months o Deep freezers ▪ They maintain temperature from -15°C to -25°C ▪ Used at primary health care for preparation of ice packs o Ice lined refrigerators ▪ These are used at district and primary health care levels ▪ They maintain temperature from +2°C to +8°C ▪ The refrigerators are top opening and they can hold cold air inside better than front opening refrigerators ▪ For front opening refrigerators; • The refrigerators should not be used for storage of anything other than vaccines • Should have uninterrupted power supply e.g. having alternative sources of power • Should not be more than 50% full • Should not be place in direct sunlight • Should not store vaccine for more than 1 month at primary health facility • Should not be used for foods or medical specimens • Nothing should be place in the fridge door • Items should be arranged away from fridge walls and cold air vents • Equipment for Transportation of Vaccines o Refrigerated vehicles ▪ Used for long-term transportation of vaccines o Cold boxes ▪ Cold boxes are insulated containers that can be lined with frozen ice packs to keep vaccines and diluent cold ▪ Used for transporting vaccines ▪ Fully frozen ice packs are placed at the bottom and sides ▪ DPT, TT and DT should not be kept in direct sunlight ▪ Cold boxes are used by health centre staff to collect and transport monthly vaccine supplies from district stores ▪ They are also used to store vaccines when the refrigerator is out of order or being defrosted ▪ The most suitable cold box for a particular health centre is determined by: • the vaccine storage capacity needed • the cold life needed, depending on the longest time that vaccine will be stored in the box • its weight, this depending on how the box will be transported, e.g., by motor vehicle or bicycle Figure56.1: A small vaccine cold box [pic] o Vaccine carriers ▪ Vaccine carriers are insulated containers that can be lined with frozen ice packs to keep vaccines and diluents cold ▪ They are smaller than cold boxes and easier to carry when walking, but they stay cold for as long as 24-72 hours ▪ These are used to carry small quantities of vaccines (16-20 vials) ▪ Four ice packs are used ▪ Vaccine carriers are used to transport vaccine and diluent to outreach sites and for temporary storage during health centre immunization sessions Figure 56.2: A large vaccine carrier [pic] o Ice packs ▪ Ice packs are flat, square plastic bottles that can be filled with water

NTA Level 5 • Semester 1 • PST05103 Introduction to Bacilli Pharmaceutical Microbiology • Source Session/Topic 13 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 13: Introduction to Bacilli Total Session Time: 60 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Describe medical bacilli Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes|Presentation |Characteristics of Bacilli | |3 |20 minutes |Presentation |Classification of Gram Positive | | | | |Bacilli | | |15 minutes |Presentation |Classification of Gram Negative | | | | |Bacilli | |4 |5 minutes |Presentation |Key Points | | 5|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Characteristics of Bacilli (10 minutes) • Bacilli are rod shaped bacteria. They are not spherical as cocci. • Bacilli should not be confused with bacillus which is a genus in the spore forming gram positive bacilli • Bacilli are groped into two major groups depending on their staining properties with Gram stain o Gram postive bacilli o Gram negative bacilli • Bacilli consist of a large number of bacteria some of which cause serious diseases in humans and others are normal flora of humans STEP 3: Classification of Gram Positive Bacilli (25 minutes) • Spore forming Gram Positive Bacilli o These bacilli are ubiquitous, and because they form spores, they can survive in the environment for many years o The gram-positive spore-forming bacilli are the Bacillus and Clostridium species ▪ Genus Clostridium • Anaerobic spore-forming bacilli • Members of the genus Clostridium are obligate anaerobic to spore forming bacilli • Found in soil as well as in normal intestinal flora of man and animals • There are both gram-positive and gram-negative species, although the majority of isolates are gram-positive • Produce exotoxin(s) which play an important role in disease production • Pathogenic members include; o Corynebacterium perfringes which causes gas gangrene o Clostridium tetani which causes tetanus o Clostridium botulinum which causes botulism o Clostridium difficile which causes pseudomembraneous colitis o Clostridium perfringes which causes food poisoning and necrotizing enteritis ▪ Genus Bacillus • Consists of aerobic or facultatively anaerobic gram positive spore-forming bacilli • Some may turn Gram negative with age • Most members of the genus bacillus are saprophytic • They are able to survive in harsh environment • They include thermophilic, psychrophilic, acidophilic, alkaliphilic, halotolerant, and halophilic representatives, which are capable of growing at temperatures, pH values, and salt concentrations at which few other organisms could survive • Pathogenic bacteria in this genus include o Bacillus anthracis which causes anthrax o Bacillus cereus which causes bacillus food poisoning • The non–spore-forming gram-positive bacilli are a diverse group of aerobic and anaerobic bacteria o They are grouped into acid-fast bacilli and non-acid fast bacilli o The acid fast bacilli include Mycobacterium and Nocardia ▪ Mycobacterium e.g. Mycobacterium tuberculosis that cause tuberculosis, Mycobacterium leprae that causes leprosy • The non-acid fast bacilli include regular bacteria and pleomorphic bacteria o The regular acid fast bacilli include Lactobacillus and Listeria ▪ Listeria e.g. Listeria monocytogenes which causes meningitis and sepsis o The pleomorphic acid fast bacilli include Corynebacterium and Propionibacterium ▪ Corynebacterium e.g. Corynebacterium diphteriae causes Diphtheria ▪ Propionibacterium acnes is associated with acne vulgaris STEP 4: Classification of Gram Negative Bacilli (15 minutes) • The Gram negative bacilli are grouped into two groups; the aerobic non enteric bacilli and the enteric bacilli • Aerobic Gram-Negative Nonenteric Bacilli o Do not ferment sugars o They include ▪ Pseudomonas e.g. Pseudomonas aeruginosa, a dangerous opportunistic pathogen ▪ Brucella e.g. Brucella species which cause brucellosis ▪ Francicella e.g. Francicella tularensis which causes Tularemia ▪ Bordetella e.g. Bordetella pertussis which cause whooping cough ▪ Legionella e.g. Legionella pneumophilia which causes legionnaire’s disease • Enteric Gram-Negative Bacilli (Enterobacteriaceae) o These are gram negative rods o They ferment glucose with acid production o Reduce nitrates into nitrites o They are oxidase positive o They are catalase positive o They are facultative anaerobic o They are motile except Shigella, Klebsiella, and Yersinia o They are non-capsulated except Klebsiella o They are non-fastidious o They grow on bile-containing agar (MacConkey agar) o Most members are opportunistic or cause secondary infections of wounds, the urinary tract and the circulatory system o They are grouped into two groups ▪ Lactose fermenters e.g. E. coli ▪ Lactose non fermenters e.g. Salmonella, Shigella, Proteus, Yersinia STEP 5: Key Points (5 minutes) • Gram positive bacilli are grouped into spore forming and non spore forming • The spore forming gram positive bacilli are grouped into bacillus and clostridia, all are pathogenic to humans • The non-spore forming are grouped into acid fast and non acid fast • Gram negative bacilli are grouped into two groups namely non enteric gram negative bacilli and the enterics (enterobacteriaceae) • Non enteric gram negative bacilli do ferment any sugar while the enterobacteriaceae ferment a varieties of sugar STEP 6: Evaluation (5 minutes) • What are the features of gram positive bacilli? • List some bacteria that are gram positive bacilli • Mention some diseases caused by gram positive bacilli • Differentiate non enteric gram negative bacilli from the enteric gram negative bacilli References Hugo and Russell (2011), Pharmaceutical Microbiology 8th Edition, Willey- Blackwel publications Karen C. Carroll et al (2013); Jawetz, Melnick and Adelberg’s Medical Microbiology 26th Ed. McGraw Hill Co. Inc. Greenwood et al (2012); Medical Microbiology, 18th edition Churchill Livingstone ← Previous TopicNext Topic →View all Pharmaceutical Microbiology topicsOpen Complete Full Notes PDF / OFFLINE

NTA Level 5 • Semester 1 • PST05103 Classification and importance of Micro organisms Pharmaceutical Microbiology • Source Session/Topic 2 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 2: Classification and importance of Micro organisms Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Differentiate between eukaryotic and prokaryotic cells • Explain classification and nomenclature of microorganisms • Explain the importance of microorganisms in pharmacy Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 | |Small group |Differences between eukaryotic and| | |30 minutes |discussion/ |prokaryotic cells | | | |Presentation | | |3 |50 minutes |Buzzing/ |Classification and nomenclature of| | | |Presentation |microorganisms | |4 |25 minutes |Presentation |Importance of microorganisms in | | | | |pharmacy | |5 |5 minutes |Presentation |Key Points | | 6|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Differences between eukaryotic and prokaryotic cells (30 minutes) |Activity: Small Group Discussion (10 minutes) | | | |DIVIDE students into small manageable groups | | | |ASK students to discuss on the following question | |What are the differences between eukaryotic and prokaryotic cells? | | | |ALLOW students to discuss for 10 minutes | | | |ALLOW few groups to present and the rest to add points not mentioned| | | | | |CLARIFY and SUMMARIZE by using the contents below | All living things are made up of cells and cells are the smallest units of any living organism. All cells are grouped into two major groups, eukaryotic and prokaryotic cells. The differences between eukaryotic cells and prokaryotic cells are summarized as follow: |Eukaryotic Cells |Prokaryotic Cells | |Larger than eukaryotic cells |Small than eukaryotic cells | |(>10um) |(<5um) | | have no rigid cell wall | have rigid cellwall | |Always have nucleus and other |No nucleus or any other | |membrane-bound organelles |membrane-bound organelles | |DNA is linear |DNA is circular, | |Ribosomes are larger (80S) |Ribosomes are small (70S) | |Have cytoskeleton |No cytoskeleton | |Move by cilia or flagella |Move by flagella | |Cell division is by mitosis or |Cell division is by binary | |meiosis |fission | |Reproduction is asexual or sexual |Reproduction is always asexual | Figure 2.1: Prokaryotic Cell [pic] Figure 2.2: Eukaryotic Cell [pic] STEP 3: Classification and nomenclature of microorganisms (50 minutes) |Activity: Buzzing (5 minutes) | | | |ASK students to pair up and buzz on the following question for 2 | |minutes | | | |What is classification of microorganisms? | | | |ALLOW few pairs to respond and let other pairs to add on points not | |mentioned | | | |WRITE their response on the flip chart/board | | | |CLARIFY and SUMMARIZE by using the content below | • Microorganisms or microbes are microscopic organisms that exist as unicellular, multicellular, or cell clusters • Microorganisms are widespread in nature and are beneficial to life, but some can cause serious harm • Microorganisms are systematically classified into taxonomic categories to facilitate research and communication • Biologic classification helps identify each form according to common properties (similarities) using a set of rules and an estimate as to how closely related it is to a common ancestor (evolutionary relationship) in a way to create an order • The first, largest, and most inclusive group under which organisms are classified is called a domain o The domain has three subgroups: bacteria, archae, and eukarya o This first group defines whether an organism is a prokaryote or a eukaryote • The second largest group is called a kingdom o There are five major kingdoms and include prokaryota (e.g. archae and bacteria), protoctista (e.g. protozoa and algae), fungi, plantae, and animalia o A kingdom is further split into phylum or division, class, order, family, genus, and species, which is the smallest group • The classification of microorganisms in these taxa employ; • Microscopic morphology • Macroscopic morphology – colony appearance • Physiological / biochemical characteristics • Chemical analysis • Serological analysis • Genetic and molecular analysis o G + C base composition o DNA analysis using genetic probes o Nucleic acid sequencing and rRNA analysis • Generally, microorganisms can be divided into six major types: bacteria, archaea, fungi, protozoa, algae, and viruses • Bacteria o Bacteria are unicellular organisms described as prokaryotic because they lack a nucleus o They exist in four major shapes: bacillus (rod shape), coccus (spherical shape), spirilla (spiral shape), and vibrio (curved shape) o Most bacteria have a peptidoglycan cell wall; they divide by binary fission; and they may possess flagella for motility o The difference in their cell wall structure is a major feature used in classifying them o According to the way their cell walls structure stains, bacteria can be classified using the Gram-staining as either ▪ Gram-positive ▪ Gram-negative o Bacteria can be further divided based on their response to gaseous oxygen into the following groups: ▪ aerobic (living in the presence of oxygen) ▪ anaerobic (living without oxygen) ▪ facultative anaerobes (can live in both environments) o According to the way they obtain energy, bacteria are classified as heterotrophs or autotrophs ▪ Autotrophs make their own food by using the energy of sunlight or chemical reactions, in which case they are called chemoautotrophs ▪ Heterotrophs obtain their energy by consuming other organisms. Bacteria that use decaying life forms as a source of energy are called saprophytes. • Viruses o Viruses are noncellular entities that consist of

NTA Level 5 • Semester 1 • PST05103 Introduction to Bacteria Pharmaceutical Microbiology • Source Session/Topic 3 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 3: Introduction to Bacteria Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Define terms used in bacteria • Describe bacterial occurrences and distributions • Classify bacterial according to staining properties, nutritional requirements and morphology Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |20 minutes |Presentation |Common Terminologies used in | | | | |bacteriology | |3 |30 minutes |Presentation |Bacterial Growth and Reproduction | |4 |20 minutes |Presentation |Characteristics of Bacteria | |5 |35 minutes |Presentation |Classification of Bacteria | |6 |5 minutes |Presentation |Key Points | | 7|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Common Terminologies Used in Bacteriology (20 minutes) • Bacteriology o Bacteriology is the study of bacteria • Bacteria o Bacteria are prokaryotic organisms that replicate by binary fission. Other prokaryotic organisms are the archaea • Bacteriostatic o A substance that inhibit replication or growth of bacteria • Bactericidal o A substance that kills the bacteria • Growth medium o A blend of nutrients where microorganisms are made to grow in the laboratory • Staining o Is the process of applying dyes to a smear of microorganisms fixed on slide in order to make certain structures visible • Microbiota o Microbial flora harboured by normal, healthy individuals • Pathogenicity o The ability of an infectious agent to cause disease • Pathogen o A microorganism capable of causing disease • Opportunistic pathogen o An agent capable of causing disease only when the host’s immunity is impaired • Infection o Multiplication of an infectious agent within the body. Multiplication of the bacteria that are part of the normal microbiota of the gastrointestinal tract, skin, and so on is generally not considered an infection • Toxigenicity o The ability of a microorganism to produce a toxin that contributes to the development of disease • Virulence o The quantitative ability of an agent to cause disease. Virulent agents cause disease when introduced into the host in small numbers. Virulence involves adherence, persistence, invasion, and toxigenicity • Carrier o A person or animal with asymptomatic infection that can be transmitted to another susceptible person or animal STEP 3: Bacterial Growth and Reproduction (30 minutes) • In bacteria growth an increase in number of cells or biomass. They increase in number via reproduction by binary fission • Bacteria population grow in exponential fashion. One cell produces two daughter cells and the two daughter cells produce four cells and so forth. • The time interval between one cell division and the next is called generation time • Bacteria growth can occur on solid surfaces (e.g. on agar plate) or in liquid (e.g. broth) • Growth in bacteria can be in open or closed culture • Bacteria growth in closed culture (closed batch liquid culture) show the following phases of growth; o Lag phase or adaptive phase o Logarithmic phase or exponential phase o Stationary phase o Decline phase • Various factors affect bacterial growth • Factors that influence bacterial growth include; o Environmental factors e.g. availability of water, nutrients, pH, oxygen concentration and solute concentration o Physicochemical factors e.g. temperature, pH, solute, availability of oxygen etc. • Optimum growth occurs at very conducive environment • Effect of various factors affecting growth e.g. temperature, can be plotted on growth rate Vs factor to clearly show impact of varying the factor on growth rate o Such plots/graphs include ▪ Growth Vs temperature ▪ Growth Vs pH ▪ Growth Vs oxygen concentration etc. • Bacteria growth requirement in the laboratory are achieved by using nutrients formulated in growth media. These are available commercially for growing different types of bacteria in the laboratory o E.g. MacConkey agar (for Gram negative bacteria), Blood agar (grows a variety of bacteria) etc. • Bacterial growth can be measured by various methods e.g. by counting the number of cells STEP 4: Characteristics of Bacteria (20 minutes) |Activity: Buzzing (5 minutes) | | | |ASK students to pair up and buzz on the following question for 2 | |minutes | | | |What are the characteristics of bacteria? | | | |ALLOW few pairs to respond and let other pairs to add on points | |not mentioned | | | |WRITE their response on the flip chart/board | | | |CLARIFY and SUMMARIZE by using the content below | • They are prokaryotic i.e. they lack nuclear membrane so no true nucleus • Bacteria are unicellular • Cell wall is made up peptidoglycan • Bacteria reproduce by binary fission • DNA is circular • They do not have membrane-bound organelles • Metabolism in bacteria i.e. variety of pathways • Movement in bacteria i.e. flagella STEP 5: Classification of Bacteria (35 minutes) • Bacteria are classified according to different criteria • Morphology o Microscopic appearance of cells i.e. bacteria are classified according to their shapes o Cocci ▪ Bacteria that are spherical in shape. They include; • Streptococci (singular: Streptococcus) –Spherical bacteria in chains • Staphylococci (singular: Staphylococcus) –Spherical bacteria in clusters • Diplococci (singular: diplococcus) –Spherical bacteria in pairs o Bacilli ▪ Bacteria that are rod-shaped or cylindrical bacteria. They include; • Streptobacilli (in chains) • Coccobacilli –short round rods, oval and they look like cocci o Spirillum ▪ Bacteria are spiral in shape o Vibrio ▪ Bacteria are comma-shaped i.e. curved-rods o Spirochete

NTA Level 5 • Semester 1 • PST05103 Internal structures and drug targets in prokaryotic cells Pharmaceutical Microbiology • Source Session/Topic 4 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 4: Internal structures and drug targets in prokaryotic cells Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Describe the structure of a bacterial cell • List functions of different bacterial organelles/structures • Describe various drug targets in the bacterial cell Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |80 minutes |Group |Description of Internal Structures| | | |discussion/ |of Bacteria | | | |Presentation | | |3 |25 minutes |Presentation |Drug Targets | |4 |5 minutes |Presentation |Key Points | | 5|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Internal Structures of Prokaryotic Cells (80 minutes) • Bacteria are one group of prokaryotes, the other group is the archaea • Bacterial structure can be described in terms of external and internal structures • Internal structures of bacterial cells are those internal to the cell wall • The bacterial cell wall and its associated structures comprise the external structures of the bacterial cell |Activity: Small Group Discussion (40 minutes) | | | |DIVIDE students into small manageable groups | | | |ASK students to discuss on the following question | |Draw a labeled diagram showing internal structures of a bacterial | |cell | |List the function(s) of each of the labeled structure | | | |ALLOW students to discuss for 30 minutes | | | |ALLOW few groups to present and the rest to add points not | |mentioned | | | |CLARIFY and SUMMARIZE by using the contents below | • The internal structure of a prokaryotic cell consists of the cytoplasm which contains enzymes needed for metabolic reactions. [pic] Source: https://www.slideshare.net/mdsalaadx1/anatomy-and-physiology- of-bacteria The Cytoplasm • The cytoplasm is an aqueous thick fluid enclosed by the cell membrane • It is made up of 80% water, and proteins (enzymes), carbohydrates, lipids, inorganic ions and many low-molecular-weight compounds • Fills the cell and it is where most cellular reactions and activities take place • It is the internal environment of the cell The cell membrane • The cell membrane is located immediately beneath the cell wall • The cell membrane is a thin membrane around the cytoplasm • The cell membrane is also called the cytoplasmic membrane or plasma membrane • It contains phospholipids, proteins and polysaccharides • The cell membrane is a vital structure and critical barrier that separates the inside of the cell from the outer environment • The gram positive bacteria have one plasma membrane while the gram negative bacteria have two plasma membranes –one is internal and the second is known as an outer membrane separated from the inner membrane by the periplasmic space Figure 4.1: Cell membrane in Gram positive and Gram negative bacteria [pic] • Functions of plasma membrane; o The plasma membrane retains the cytoplasm, particularly in cells without cell walls, and separates it from the surroundings o Plasma membranes serve as a selectively permeable barrier; it allows particular ions and molecules to pass, either into or out of the cell, while preventing the movement of others o Transport systems can be used for such tasks as nutrient uptake, waste excretion, and protein secretion o The plasma membrane also is the location of a variety of crucial metabolic processes; respiration, photosynthesis, the synthesis of lipids and cell wall constituents, and probably chromosome segregation. Mesosomes • In gram positive bacteria, the plasma membrane forms in folding • The infolding form structures called mesosomes within cytoplasm • The mesosomes are associated with bacterial nuclear material and its replication • Respiratory enzymes are also associated with mesosomes • Functions of mesosomes o They are imvolved in cell wall formation during cell division. o They play a role in replication of chromosome and distribution to daughter cells. o They are also involved in secretary processes Nucleoid • Nucleoid is an area within the cytoplasm of a prokaryotic cell where DNA is located • It is equivalent to the nucleus in eukaryotic cells • It is not enclosed in a membrane i.e. no nuclear membrane (not a true nucleus) but it is visibly separate from the rest of the cell interior. • The bacterial DNA is single-stranded, circular and haploid Plastids • Prokaryotic cells do not have mitochondria or chloroplast o The electron transport enzymes are located in the cytoplasmic membrane o Photosynthetic pigments (Carotenoids, bacterial chlorophyll) of photosynthetic bacteria are located below the cell membrane o In some Cyanobacteria (blue-green algae), the photosynthetic structures are called Thylakoids o Thylakoids contain light harvesting pigments called phycobilins o Plastids provide energy for the prokaryotic cell as well as carrying out photosynthesis process in cyanobacteria Inclusion or storage granules • Inclusion granules are storage structures within the bacterial cytoplasm • There are several types of storage granules for nutrients in prokaryotic cells o i.e. they serve as energy and nutrient reservoirs • Nutrients may be stored in the cytoplasm in the form of lipids, glycogen, polyphosphate (and sometimes sulphur (volutin granules) or nitrogen • When source of nitrogen, sulphur, or phosphorus is limited or when pH is low, excess CO2 in the medium may be converted to “Poly-β- hydroxybutric acid, starch and glycogen which are used as energy sources Endospores • Some bacteria (e.g. Clostridium) form spores that are very resistant to drought, high temperatures and other hazards of

NTA Level 5 • Semester 1 • PST05103 External structures and drug targets in prokaryotic cells Pharmaceutical Microbiology • Source Session/Topic 5 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 5: External structures and drug targets in prokaryotic cells Total Session Time: 120 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • Describe the structure of a bacterial cell • List functions of different bacterial organelles/structures • Describe various drug targets in the bacterial cell Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |50 minutes |Presentation |External structures of prokaryotic| | | | |cells | |3 |25 minutes |Presentation |Drug Targets in Bacterial Cell | | | | |Wall | |4 |30 minutes |Presentation |Acid fast Bacilli | |5 |5 minutes |Presentation |Key Points | | 6|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Bacterial External Structures and Drug Targets (50 minutes) • Bacterial External Structures o External structures include the cell wall and structures external to it • Bacterial Cell wall o A cell wall is a layer located outside the cell membrane found in plants, fungi, bacteria, algae, and archaea. o The bacterial cell wall is a rigid structure outside the cell membrane (and inner to the capsule for capsulated bacteria) composed of peptidoglycan layers making up a cell envelope around the cell o Peptidoglycan is composed of disaccharides and amino acids which gives structural support to the bacteria o Peptidoglycan is unique to bacteria Figure 5.1: Structure of Peptidogycan [pic] ▪ Molecules making up the peptidoglycan include; • Alternating NAM and NAG chains • A tetrapeptide chain • A petaglycin chain [pic] o Bacteria are classified as being either Gram-positive or Gram- negative based in differences in the structure of their peptidoglycan cell wall o Gram-positive bacteria are stained dark blue or violet by Gram staining o In Gram-positive bacteria, the cell wall is thick and consists of several layers of peptidoglycan o Gram negative bacteria lack the outer membrane envelope found in Gram-negative bacteria ▪ They contain teichoic acids in the peptidoglycan. • Teichoic acids are unique to the Gram-positive cell wall • Teichoic acids are linear polymers of polyglycerol or polyribitol substituted with phosphates and a few amino acids and sugars ▪ immune response when the bacteria infect animals o Functions of the bacterial cell wall; ▪ To enclose and protect the internal structures ▪ To protect the bacteria from osmotic lysis ▪ Provide shape to the bacteria • Structures external to the cell wall include; ▪ Flagella • Flagella are long protein filaments of uniform length that are responsible for cell motility • They are whip-like structure that allows a cell to move • Types and examples of flagella o Monotrichous –Single polar flagellum e.g. Vibrio cholerae o Amphitrichous –Single flagellum on both sides e.g. Alkaligens faecalis o Lophotrichous –Tufts of flagella at one or both sides e.g. Spirillum o Peritrichous–Numerous flagella all over the bacterial body ▪ Pili • Pili (singular: pilus) are hair-like appendages found on the surface of some bacteria. They are made up of proteins called pilins • Pilli are classified into Ordinary pili or Sex pili according to their morphology, distribution, and function • The pilus is found on the surface of many gram-positive bacteria and some gram-negative bacteria • Pili function as adhesive factors for mucosal surface attachment ▪ Capsule • A capsule is a discrete detectable layer of polysaccharides deposited outside the cell wall • Capsule is attached tightly to the bacterium and has definite boundaries • Capsules are considered virulence factors because they protect a bacterial cell from ingestion and destruction by white blood cells (phagocytosis) ▪ Slime layer • • A slime layer in bacteria is an easily removable (e.g. by centrifugation), unorganized layer of extracellular material that surrounds bacteria cells • A slime layer is loosely associated with the bacterium and can be easily washed off • The slime layer is usually composed of polysaccharides and it may serve to trap nutrients, to aid in cell motility, to bind cells together or to adhere to smooth surfaces STEP 3: Drug Targets in Bacterial Cell Wall (25 minutes) • Cell Biosynthetic Enzymes o Fosfomycin o Cycloserin • Carrier Molecules o Bacitracin • Cell wall substrates o Vancomycin • Enzymes that Catalyse Crosslinking of peptidoglycan subunits (Transpeptidases) o Penicillins o Cephalosporins o Carbapenems o Monobactams STEP 4: Acid-fast Bacteria (30 minutes) • Acid-Fast Bacteria possess a unique cell wall architecture different from both gram negative and gram positive bacteria • The Acid-Fast cell wall consists of a thick, outer lipid-rich layer composed primarily of the fatty acid "Mycolic Acid" • This lipid layer lies on top of a layer of peptidoglycan and the sugar arabinogalactan which in turn invest the inner lipid membrane common to all bacteria • The thick outer mycolic acid layer renders acid-fast bacteria resistant to gram stain. • When stained with alternative dyes, the cell wall is resistant to decolorization with acid alcohol, thus their name "Acid-Fast” • The cell wall is characterized by; o A thin layer of peptidoglycan [pic] • Function of the Cell wall components of Acid-fast bacilli o The peptidoglycan prevents osmotic lysis o The arabinogalactan layer is linked to both the peptidoglycan and to the mycolic acid outer membrane and probably provides additional strength to the cell wall o The mycolic acids and other glycolipids also impede the entry of chemicals causing the organisms to grow slowly and be more

NTA Level 5 • Semester 1 • PST05103 Introduction to Staphylococci Pharmaceutical Microbiology • Source Session/Topic 6 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 6: Introduction to Staphylococci Total Session Time: 60 minutes Pre-requisites • Human anatomy and physiology Students Learning Tasks By the end of this session students are expected to be able to: • List characteristic of the medical Staphylococci Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |5 minutes |Presentation |Introduction, Learning Tasks | |2 |15 minutes |Presentation |Characteristics of Staphylococci | |3 |10 minutes |Presentation |Human Staphylococcal Pathogens | |4 |20 minutes |Presentation |Epidemiology and Pathogenesis of | | | | |the Staphylococci | |5 |5 minutes |Presentation |Key Points | | 6|5 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Characteristics of Staphylococci (15 minutes) • Staphylococcus is a genus of Gram-positive spherical bacteria (cocci) which grow in grape-like clusters • Staphylococci are catalase positive (this distinguishes them from Streptococci which are catalase negative). The enzyme catalase breaks down hydrogen peroxide into water and oxygen. • Staphylococci are widely distributed; some are normal flora while others are pathogenic to humans causing many forms of infections. • Staphylococcus aureus colonizes the nasal passage and axillae while Staphylococcus epidermidis is a common human skin commensal. Other species of staphylococci are infrequent human commensals and other animals. • Staphylococci are salt tolerant and often hemolytic • S. aureus and Staphylococcus intermedius are coagulase positive. Coagulase enzyme clots blood plasma • All other staphylococci are coagulase negative STEP 3: Human Staphylococcal Pathogens (10 minutes) • Most staphylococci are not pathogenic to humans • Human pathogens include; o S. aureus ▪ which is the most pathogenic of the staphylococci ▪ leading cause of nosocomial infections o S. epidermidis ▪ Causes infections of prosthetic heart valves and hips ▪ It is a common member of the skin normal flora o S. saprophyticus ▪ Which causes urinary tract infection STEP 4: Epidemiology and Pathogenesis of the Staphylococci (20 minutes) • Infections caused staphylococci include; o Skin infections, pneumonia, endocarditis, osteomyelitis and septic arthritis which are due to direct tissue invasion by the bacteria o Toxic shock syndrome, staphylococcal scalded skin syndrome, staphylococcal food poisoning which are toxin-mediated • S aureus causes many forms of infection in humans; o Superficial skin lesions (boils, styes) and more serious skin infections e.g. furunculosis o Toxin-mediated infections e.g. food poisoning o Localized abscesses o Deep-seated infections, such as osteomyelitis and endocarditis • S. aureus expresses many potential virulence factors o Surface proteins that promote colonization of host tissues o Factors that probably inhibit phagocytosis e.g. capsule, immunoglobulin binding protein o Toxins that damage host tissues and cause disease symptoms • Coagulase-negative staphylococci are normally less virulent and express fewer virulence factors o S. epidermidis are skin normal flora that readily colonize implanted devices e.g. prosthetic heart valves • Pathogenic staphylococci are transmitted by shedding from human lesions and contaminated formites such as clothing and bed linens. Heavily contaminated environment and compromised immunity favour infection by members of the genus • Manifestations of disease caused by Staphylococci are inflammatory and toxin-mediated o Inflammatory manifestations range from superficial skin lesions to deep osteomyelitis to septicaemia • Multiple antibiotic resistance is increasingly common in S. aureus and S epidermidis • Methicillin resistance indicates multiple resistance • Methicillin-resistant S aureus (MRSA) causes outbreaks in hospitals and can be epidemic • Infections acquired outside hospitals can usually be treated with penicillinase-resistant β-lactams • Hospital acquired infections are often caused by antibiotic resistant strains and can only be treated with vancomycin STEP 5: Key Points (5 minutes) • Staphylococci can cause many forms of infection • Staphylococci are Gram-positive cocci 1μm in diameter and grown in grape-like clusters • Staphylococci are catalase positive • S. aureus and S. intermedius are coagulase positive while all other staphylococci are coagulase negative STEP 6: Evaluation (5 minutes) • Mention four characteristics of staphylococci • S. causes which diseases in humans? • How are staphylococcal infections acquired? References Hugo and Russell (2011), Pharmaceutical Microbiology 8th Edition, Willey- Blackwel publications Karen C. Carroll et al (2013); Jawetz, Melnick and Adelberg’s Medical Microbiology 26th Ed. McGraw Hill Co. Inc. Greenwood et al (2012); Medical Microbiology, 18th edition Churchill Livingstone ← Previous TopicNext Topic →View all Pharmaceutical Microbiology topicsOpen Complete Full Notes PDF / OFFLINE NOTES Unataka kutumiwa notes hizi kupitia WhatsApp?Kwa notes zilizopangiliwa vizuri kwa kusoma offline au PDF, bonyeza kitufe hapa chini. Ujumbe wenye Level, Semester, Module na Topic utaandaliwa moja kwa moja.TUMIWA NOTES WHATSAPP WhatsApp: 255620339260