Infectious Diseases - Empirical Therapies

Skin

Cellulitis

Strep. pyogenes
± Staph. aureus

Mild/Moderate (oral)
Penicillin V + flucloxacillin
or Co-amoxyclav alone
or Erythromycin alone (if penicillin allergic)

Severe (IV)
Benzylpenicillin + flucloxacillin
or Co-amoxyclav alone

Bones & Joints

Osteomyelitis & Septic Arthritis
Staph. Aureus

Streptococci

Staph Epidermidis

ALL CASES ARE SEVERE
IV Flucloxacillin (+ fusidic acid for osteomyelitis)
or Clindamycin alone

ENT Infections

Sinusitis & Otitis Media

Viruses
Strep. pneumoniae

Haemophilus influenzae

Nothing
or Amoxycillin
or Erythromycin

Throat Infections

Viruses

Strep. pyogenes

Nothing

or Penicillin V

or Erythromycin

Respiratory Infections

Community Acquired Pneumonia
Pneumococcus (Strep. pneumoniae)
‘Atypicals’

- Mycoplasma pneumoniae

- Chlamydia pneumoniae

- Legionella

Mild/Moderate (oral)
Amoxycillin 

+ Erythromycin (if ‘atypical suspected’)

or Erythromycin alone

Severe (IV)
Co-amoxiclav

or 2nd/3rdgen. cephalosporin + Macrolide

Pulmonary tuberculosis

Mycobacterium tuberculosis

Rifampicin + Isoniazid + Pyrazinamide + Ethambutol (2 months)
Rifampicin + Isoniazid (4 months)

Acute Exacerbations of COPD
Pneumococcus (Strep. pneumoniae)

Haemophilus influenzae

Moraxella catarrhalis

Amoxycillin + Clarithromycin

or Tetracycline (if penicillin allergic)

Urinary Tract

Urinary Tract Infection
E. Coli (60-90%)
Proteus (10%)
Klebsiella

Mild/Moderate (oral)
Trimethoprim (unless pregnant)
or Amoxycillin

or Nitrofurantoin

or Ciprofloxacin
(A 3-day course is usually sufficient)

Severe (IV)

Co-amoxiclav

or 2nd/3rd gen. cephalosporin ± gentamicin

GI Tract Infections

Gastro-enteritis
Often viral and self-limiting
No antibiotic usually indicated

Campylobacter
Ciprofloxacin

Salmonella
Ciprofloxacin

Typhoid fever
Ciprofloxacin

Pseudomembranous colitis
Oral metronidazole

or Oral Vancomycin

GI Tract Surgery & Peritonitis - Antibiotic Prophylaxis and Treatment

Staph. aureus (wounds)
Mixed faecal flora including anaerobe

2nd/3rd gen. cephalosporin + metronidazole

or Co-amoxyclav alone

Meningitis

Meningococcus (N. meningitidis)

Pneumococcus (Strep. pneumoniae)

Haemophilus influenzae

ALL CASES ARE SEVERE

Ceftriaxone IV

Prophylaxis for Meningococcal contacts

Rifampicin

or Ciprofloxacin

Septicaemia

Many possible causes

‘Blind therapy’ is broad spectrum + additional cover for strong clinical suspicion
Definitive therapy based on culture results

Community Acquired

Ceftriaxone ± gentamicin
Add Metronidazole if anaerobes suspected
Add Flucloxacillin is Staph. aureus suspected
Add Vancomycin if MRSA suspected