Microbiology, Parasitology & Entomology – mycobacterium and spirochaetes session 4
Read the complete lesson in an organized slide-by-slide format. This topic contains 42 learning sections from the source presentation.
LESSON CONTENTS — 42 SECTIONS
Session 4: Mycobacteria and Spirochaetes
Learning objectives
By the end of this session, students are expected to be able to:
- Define Mycobacteria and Spirochetes
- List Mycobacteria of medical importance
- Describe general characteristics of mycobacterium of medical importance
Learning objectives cont..
- Identify specimen used to diagnose Mycobacteria of medical importance
- List laboratory techniques used to diagnose Mycobacteria
- Identify drugs of choice for Mycobacteria diseases
- List Spirochetes of medical importance (Treponema pallidum and Borrelia spp)
- Describe general characteristics of Spirochetes of medical importance
Learning objectives cont..
- Mention diseases caused by Spirochetes
- Identify specimen used to diagnose Spirochetes of medical importance
- List laboratory techniques used to diagnose spirochetes
- Identify drugs of choice for treatment of diseases caused by spirochetes
Define Mycobacterium
Mycobacterium:. Is a rod-shaped, aerobic bacteria that do not form spores
They are stained by Ziehl Neelsen (ZN) stain, they resist decolorization by acid or alcohol and are therefore called “acid-fast” bacilli (AFB).
During the staining process the tend to appear red as they stain primary color( strong carbolfuchsin)
Mycobacteria of medical importance
Mycobacterium tuberculosis
Mycobacterium leprae
General Characteristics and Morphology of Mycobacteria[Acid Fast Bacilli]
They are slightly curved rod shaped, thin, and filamentous forms are common
Cell wall contains high concentration of lipids – mycolic acids (hence Mycobactirum)
Obligate aerobes
Acid-fast bacilli
General Characteristics and Morphology ofMycobacteria[Acid Fast Bacilli]
They are very sensitive to UV light
Very slow growing (temperature for growth ranges from 35 to 37oC)
They are also called Acid Fast bacilli however they are resistant to acids
Mycobacterium Tuberculae
Tuberculosis
The two types of clinical manifestation of tuberculosis (TB) are pulmonary TB (PTB) and extrapulmonary TB (EPTB). The former is most common.
EPTB refers to TB involving organs other than the lungs (e.g., pleura, lymph nodes, abdomen, genitourinary tract, skin, joints and bones, or meninges)
Pulmonary tuberculosis
Pulmonary tuberculosis (TB) is a contagious, infectious disease that attacks your lungs. Latent TB means you have the germ but you aren’t showing the symptoms and aren’t contagious.
You can treat pulmonary TB with antibiotics, but you must finish all your medications to prevent it from returning.
Tuberculosis
Extrapulmonary Tuberculosis
Extrapulmonary Tuberculosis (TB) is TB which occurs in any other part of the body outside the lungs. Many people do not realise it but TB can infect almost any place in the body: the inner organs, the bone, the brain, the spine etc.
Slide 14
Leprosis
Leprosy It is a chronic infectious disease which is caused by a type of bacteria called Mycobacterium leprae.
The disease affects the skin, the peripheral nerves, mucosa of the upper respiratory tract, and the eyes.
Specimen used to diagnose Mycobacteria of medical importance
Sputum
Gastric washing
Urine
Pleural fluid
Cerebral spinal fluid
Synovial fluid
Biopsy materials
Blood
Laboratory techniques used to diagnose Mycobacteria
ZN Ziehl Neelsen stain
culture
Drugs of choice for Mycobacteria diseases
Rifampicin
isoniazid
Ethambutol
Pyrazinamide
Streptomycin
Dapsone
clofazimine
Slide 19
Definition Spirochaetes
Spirochaetes: Are thin walled, flexible spiral shaped bacteria. Examples of spirochaetes include Treponema species, Borrelia species
General Characteristics and Structure of Spirochaetes
They are thin walled flexible, spiral rods
They are motile
They are flagellated (endoflagella
They are not readily stained by gram stain
They have a lipid rich outer membrane
General Structure of spiochaetes
The spirochaetes cell consists of a protoplasmic cylinder surrounded by plasma membrane and gram-negative type cell wall.
They have axial fibrils, periplasmic flagella or endoflagella located in the periplasm.
The whole complex of periplasmic flagella is called axial filament.
Both the axial filament is surrounded by a multilayered but flexible outer membrane
General Structure of spirochaetes
specimen used to diagnose Spirochetes of medical importance
Serous fluid from chancre
Blood
Biopsy
Laboratory techniques used to diagnose spirochetes
Dark field illumination
Serology RPR
Silver impregnation
Giemsa stained blood slide
Drugs of choice for treatment of diseases caused by spirochetes
Benzathin penicillin
Benzyl penicillin
Erthyomycin
Penicillin
Tetracycline
Doxycycline
Spirochaetes of Medical Importance
Syphilis infection
Stage of syphilis infection
primary stage of syphilis
During the primary stage of syphilis, a sore (chancre) that is usually painless develops at the site where the bacteria entered the body. This commonly occurs within 3 weeks of exposure but can range from 10 to 90 days. A person is highly contagious during the primary stage.
Primary stage
Secondary Syphilis.
Secondary Syphilis. In this stage, the pathogen spreads through the blood to the skin, liver, joints, lymph nodes, muscles, and brain. A rash frequently appears about 6 weeks to 3 months after the chancre has healed. The rash may cover any part of the body, but tends to erupt on the palms or soles of the feet.
Secondary syphilis
third stage of syphilis
The third stage of syphilis is the latent or hidden stage. The primary and secondary symptoms disappear, and you won’t have any noticeable symptoms at this stage. However, you will still be infected with syphilis
Tertiary stage
Relapsing fever
Relapsing fever is a vector-borne disease caused by infection with certain bacteria in the genus Borrelia which are transmitted through the bites of lice or soft-bodied ticks (genus Ornithodoros
Signs and symptoms
Most people who are infected develop sickness between five and 15 days after they are bitten. The symptoms may include a sudden fever, chills, headaches, muscle or joint aches, and nausea. A rash may also occur. These symptoms usually continue for two to 9 days, then disappear. This cycle may continue for several weeks if the person is not treated
Ticks
KEY POINTS
Mcobacteria are rod-shaped, aerobic bacteria that do not form spores stain by ziehl neelsen stain as they resist decolarization due to their cell wall contain mycolic acid.
Mycobacterium tuberculae they cause pulmonary tuberculosis and extratuberculosis while mycobacterium leprae cause leprosis.
Spirochaetes- are thin walled, flexible spiral shaped bacteria. Examples are treponema species and borellia species.
Syphilis infection has different stages.
EVALUATION
Define mycobacterium and spirochaetes.
List disease caused by mycobacteria species and spirochaetes species
Describe stage of syphilis infections.
What is relapsing fever and mention sign and symptoms associated.
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