Bacillus spp - other than B. cereus group
(> 70 species)
Gram Stain
- Gram positive large spore forming bacilli (aerobic/facultative)
Clinical Significance
These organisms are widely distributed in nature, especially soil environments. Their spores may contaminate dried foods (spices/tea/flour/powders).
These organisms are low level pathogens that typically represent environmental contamination of cultures.
They have rarely been associated with septicemia, endocarditis, brain abscesses, peritonitis, wound and ocular infections typically in immunocompromised patients.
Some species can cause diarrheal illness.
Usual Susceptibility Pattern
Non–cereus group Bacillus species are typically susceptible to ampicillin, penicillin, ceftriaxone, imipenem, clindamycin, macrolides, vancomycin (rare resistance reported), linezolid, and aminoglycosides.
Lysinibacillus and Paenibacillus spp- Many strains are resistant to penicillin/ampicillin. Susceptibility to ceftriaxone, clindamycin, macrolides, tetracyclines , quinolones, vancomycin and TMP-SMX is variable. Most are susceptible to linezolid.
Daptomycin MICs are often elevated – possibly due to resistance in spores with reversion to susceptibility on germination.
| Empiric Therapy |
|---|
| Clinically Significant Infection: |
|
Penicillin Lysinibacillus and Paenibacillus - vancomycin or linezolid |