| Causative organism |
Estimated frequency |
Gram-Positive Bacteria
Staphylococcus species (S. aureus, S. epidermidis)
Streptococcus species (S. pyogenes, S. pneumoniae) |
35-40% |
Gram-Negative Bacteria
Campylobacter jejuni
Klebsiella species
Haemophilus influenzae
Salmonella species
Escherichia coli (facultative anaerobe)
Pseudomonas aeruginosa
Acinetobacter and many others |
25% |
Anaerobes (Gram-positive and -negative)
Bacteroides species
Actinomyces species
Clostridium septicum among others |
9-12%
(Often polymicrobial culture) |
Mycobacteria
Mycobacterium tuberculosis
Atypical mycobacteria (e.g. Mycobacterium avium intracellulare) |
9% |
Fungal
Pneumocystis jiroveci
Aspergillus species
Candida species
Blastomyces dermatitidis
Coccidioides immitis |
Approx 15% |
Parasite
Echinococcus species, and others |
Less than 1% |
| Polymicrobial culture |
25- 30% |
