Aerobic Gram Positive Bacteria

COCCI

Micrococcus

• flucloxacillin
• vancomycin

Staphylococcus aureus

• flucloxaciliin 100mg/kg/day in divided doses
• clindamycin 4mg/kg Q6hrly
• piperacillin-tazobactam
• cephazolin
• co-trimoxazole 10mg/kg of sulphamethoxazole
• erythromycin 20mg/kg/day in divided doses
• fusidic acid 1g Q8hrly
• gentamicin 3-5mg/kg LD -> titrate to trough
• tetracycline 500mg Q12hrly

• vancomycin 10mg/kg LD -> dose as per trough level
• linezolid 600mg Q12hrly (adult)
• meropenem 1g Q8hrly (adult)
• quinpristin-dalfopristin 7.5mg/kg Q8hrly
• rifampicin 20mg/kg /day
• teicoplanin 400mg LD -> 400mg @ 12 hrs -> 400mg Q24hrly
• tigecycline 100mg LD -> 50mg Q12hrly

-> penicillin = waste of time
-> MRSA is resistant to imipenem

Coag Negative Staphylococcus (from blood)

• vancomycin 10mg/kg LD -> dose as per trough level
• linezolid 600mg Q12hrly (adult)
• meropenem 1g Q8hrly (adult)
• quinpristin-dalfopristin 7.5mg/kg Q8hrly
• rifampicin 20mg/kg /day
• teicoplanin 400mg LD -> 400mg @ 12 hrs -> 400mg Q24hrly
• tigecycline 100mg LD -> 50mg Q12hrly

-> penicillin, fluclox and erythromycin = waste of time
-> clindamycin, co-trimoxazole and gentamicin = basically a waste of time

Staphylococcus saprophyticus

• penicillin

Streptococcus + Enterococcus

A – S. pyogenes

• penicillin G
• penicillin V
• erythromycin

-> in invasive infections (toxic shock syndrome or necrotising fasciitis) consider adding clindamycin

B – Streptococcus agalactiae (beta-haemolytic)

• penicillin G

C and G

• penicillin

D

Enterococcus

• penicillin G
• benzylpenicillin 1-5g/day in divided doses
• amoxicillin 1g Q4 hrly
• vancomycin 10mg/kg LD -> dose as per trough level
• nitrofurantoin 100mg QID PO (5-7mg/kg/day)

-> tetracycline and gentamicin = waste of time
-> facecalis: amoxicillin, imipenem
-> faceium: vancomycin (resistant to imipenem)
-> VRE: linezolid

Streptococcus bovis

• ampicillin
• penicillin
• vancomycin

Streptococcus pneumoniae

• moxifloxacin – 400mg Q24 hrly (drug of choice)
• penicillin – becomes less sensitive with decreasing age
  – amoxicillin 1g Q4 hrly
  – benzylpenicillin 1-5g/day in divided doses
  – ceftriaxone (good cover for all age groups) 1-4g Q24hrs
  – cefotaxime
  – vancomycin
  – linezolid

Viridans Group – Streptococcus mutans, mitis, sanguinis, salavarius, constellatus

• penicillin G
• gentamicin + either: ampicillin, penicillin or vancomycin
• vancomycin

RODS/BACILLI

Bacillus

• anthracis: penicillin G, erythromycin
• cereus: vancomycin, clindamycin

Corynebacterium

• antitoxin, penicillin or erythromycin, vaccination (DPT)

Erysipelothrix

• amoxycillin
• penicillin

Lactobacillus

• penicillin

Listeria

• ampicillin
• co-trimoxazole 10mg/kg of sulphamethoxazole

Nocardia

• co-trimoxazole 10mg/kg of sulphamethoxazole
• ceftriaxone
• meropenem

-> sensitivities vary according to species and strain – empiric combinatorial therapy often requred