Gram positive bacteria

Question 1

Classes of gram positive cocci

Answer 1

1. Staphylococci
2. Streptococci
3. Enterococci

Question 2

Classes of staphylococci

Answer 2

1. Coagulase positive staph

2. Coagulase negtative staph

Question 3

Coagulase positive staph

• Organisms
• Infections

Answer 3

• Staph aureus (skin flora)

- Cellulitis, bone/joint infections, endocarditis, bloodstream

Question 4

Coagulase negative staph

• Organisms
• General thoughts about each

Answer 4

• Staph epidermidis, staph lugdenensis, staph saprophyticus
• Staph epidermidis & saprophyticus are usually contaminants
• Staph lugdenensis should be treated like a staph aureus

Question 5

Enterococci

• Organisms
• Sensitivities
• Infections

Answer 5

1. Enterococcus faecalis (s for sensitive): sensitive to amp/amoxicillin, benpen, vanc. <5% are VREs
2. Enterococcus faecium (m for malevolent - resistance - 80% at The Alfred are VREs)

Enterococci cause UTI, bloodstream infections, infective endocarditis. Neither are particularly nasty bugs

Question 6

What can you treat VRE with?

Answer 6

Linezolid
Daptomycin
+/- teicoplanin

Question 7

Classes of streptococci

Answer 7

1. Alpha haemolytic (partial haemolysis)

2. Beta haemolytic (full haemolysis)

Question 8

Alpha haemolytic streptococci

• Organisms
• Infections

Answer 8

• Strep pneumoniae: encapsulated. Infects asplenic, unvaccinated, immunosuppressed. Do a HIV test in anyone with a strep pneumoniae infection. Causes CAP, meningitis, sepsis, sinus/ENT
• Viridans group strep (most important strep mitis) - causes IE. Everyone with strep mitis bacteraemia gets a TTE

(alphas use VPNs - viridans, pneum)

Question 9

Beta haemolytic streptococci

• Groups and organisms
• Infections
• Special features for group A and D

Answer 9

• Group A: strep pyogenes: cellulitis, URTI, nec fac. Special features: toxin producing –> causes rheumatic fever, post strep GN, scarlett fever
• Group B: strep agalacticae (GBS)
• Group C/G: strep dysgalacticae
• Group D: strep bovis. High association with CRC - everyone gets an OP scope

Question 10

Gram positive bacilli - groups

Answer 10

1. Cutibacterium acnes
2. Corynebacterium spp.
3. Bacillus spp.
4. Nocardia
5. Listeria monocytogenes
6. Clostridium spp.

Question 11

Corynebacterium spp.

Answer 11

1. Corynebacterium diphtheriae (diphtheria): first sign is grey patch in the throat
2. Non diphtherial corynebacterium

Question 12

Bacillus spp.

Answer 12

1. Bacillus cereus: from undercooked rice. Causes gastrointestinal disease.
2. Bacillus anthracis: cutaneous, lung and GI manifestations. Lung and GI anthrax have an incredibly high fatality rate

Question 13

Nocardia

• Organ involvement
• Which patients

Answer 13

Involves brain, lungs and skin
Every patient with nocardia in the lungs gets brain imaging

Only really seen in immunocompromised hosts

Weakly acid fast

Question 14

Clostridium spp.

Answer 14

Toxin producing

1. C difficile
2. C botulinum (causes botulism - flaccid paralysis)
3. C tetani (rigid paralysis)
4. C perfringens (gas gangrene)