24. Gram +ve Aerobic Rods & Mycobacteria Flashcards
Name the Aerobic gram +ve rods.
- Bacillus
- Lactobacillus
- Corynebacterium diphtheria
- Listeria monocytogenes
- Norcadia
- Actinomyces
Most species of Corynebacterium is commensal on skin, which is species is pathological?
Corynebacterium diphtheria.
- produces diphteria toxin that can cause 1. Myocarditis 2. Nerve damage
What are the symptoms of coryndebacterium diphtheria?
- Bull neck (lymphadenopathy)
- Sore throat/ pseudomembrane (basically leathery white layer at the back of the throat w lots of pus)
- Cutaneous lesions
Toxin mediated effects
1. Myocarditis
2. Nerve damage (neuropathy)
How is C. Diphtheria managed?
- Toxoid vaccine given in childhood.
- Can be treated w ABs : penicillin & erythromycin
- PEP: post exposure antibiotic prophylaxis
What does the c. Diphtheriae vaccine do?
- doesnt prevent infection, only prevents colonisation
- most sgporeans are protected cuz vaccine is given at birth, more worried in foreign workers who havent been vacciated
How is Listeria transmitted?
- food borne
- special, can thrive even at cold temps, unlike many other bacteria
Listeria is more common in the..
Immunocompromised or extremes of ages (very young or very old)
How does Listeria manifest?
- usually gastroenteritis (foodborne outbreaks)
- invasive diseases 1. Bacteremia 2. Meningitis/Focal CNS lesions
- is why pregnant women are advised against eating cheese. Can cause miscarriage
(Bacteria prolly invades through GI)
How is Listeria managed?
Ampicillin (+ gentamicin for synergistic effect)
What is Actinomyces/ Actinomycosis characterised by?
- pus
- sulphur granules
- filamentous gram +ve branching rods (when u look closer w microscope)
[T/F] actinomyces is usually commensal
true
- colonises almost every part of the body
What are the 3 most common actinomycosis sites?
- Orocervicofacial (50%)
- Thoracic (15-20%)
- Abdominopelvic (20%)
What is empyema necessitans?
Empyema necessitans is a rare complication of pleural space infections and occurs when the infected fluid dissects spontaneously into the chest wall from the pleural space
- very few pathogens cross planes
- actinomyces is one of them, invades onwards and doesnt confine to one organ
treatment of actinomycosis
- natural penicillin usually works
- 2 phases of tx 1. intensive 2. consolidative
- takes rlly long to treat
when culturing nocardia, what is significant about it
- most bacteria lies flat on agar plate
- but nocardia grows upwards like a fungus
