Gram Positive Bacteria (Bacilli)

Question 1

*Bacillus anthracis - *aerobic, spore-forming

Answer 1

• Anthrax
• 3 toxins –> oedema factor, protective antigen and lethal factor
• Cutaneous, inahalational or GI infection
• Rx - benzylpenicillin or ciprofloxacin

Question 2

*Bacillus cereus - *aerobic, spore-forming

Answer 2

• Emetic food poisoning
• Grows on rice dishes in 1-5 hours
• Diarrhoea and abdominal pain
• Lasts 8-16 hours
• Usually self-limiting

Question 3

Clostridium botulinum - anaerobic, spore-forming

Answer 3

• Botulism (classic food-borne)
• Infant botulism - from honey
• Wound botulism - IVDU
• Rx - supportive and anti-toxin
• Wound botulism –> consider debridement
• benzylpenicillin or metronidazole

Question 4

*Clostridium difficile - *anaerobic, spore-forming

Answer 4

• Antibiotic-associated diarrhoea
• Pseudomembranous colitis
• Rx - oral metronidazole or vancomycin

Question 5

Clostridium perfringens - anaerobic, spore-forming

Answer 5

• Food poisoining (self-limiting
• ‘Pigbel’ - clostridium necrotising enteritis
• Gas gangrene: Rx - debridement with benzylpenicillin or metronidazole

Question 6

*Clostridium tetani *- anaerobic, spore-forming

Answer 6

• Tetanus
• Vaccine +/- human tetanus immunoglobulin (HTIG) in non-immune
• Rx - supportive with HTIG plus metronidazole

Question 7

*Corynebacterium species (non-diptheria strains) - * aerobic, non-sporing, non-branching

Answer 7

• Club shaped
• Commensals

Question 8

*Corynebacterium diphtheria - *aerobic, non-sporing, non-branching

Answer 8

• Some strains are toxigenic (diptheria toxin)
• Respiratory tract diptheria
• Cutaneous diptheria
• Diptheria toxin vaccine (dT)
• Rx: Horse diptheria antitoxin plus penicillin or erythromycin

Question 9

Listeria monocytogenes - aerobic, non-sporing, non-branching

Answer 9

• Tumbling motility
• Beta-haemolytic
• Food-borne
• Listeriosis in pregnancy
• Neonatal listeriosis
• Listeria meningitis
• Cephalosporin resistant
• Rx - amoxicillin and gentamicin

Question 10

Priopionibacterium species - anaerobic, non-sporing, non-branching.

Answer 10

• Skin commensal
• Slow growing
• Cause of acne vulgaris (P.acnes)
• Rx - tetracyclines

Question 11

*Nocardia species - *aerobic, branching

Answer 11

• Partially acid-fast
• Pulmonary, cutaneous and systemic infections including brain abscesses
• Rx - co-trimoxazole

Question 12

*Actinomyces species - * anaerobic, branching

Answer 12

• IUD-related infections
• Cervicofacial infections (actinomycosis)
• Rx - benzylpenicillin (IV) or amoxicillin (PO)