Bacillus subtilis

Infections and Diseases

Rarely pathogenic

Opportunistic infections in immunocompromised people and hospitals.

Foodborne illness: Spore contamination in food

Self-limiting (mild diarrhea, nausea)

Can cause eye infections (keratitis, endophthalmitis) in rare cases.

Rod-shaped (Bacillus)

Typically single or in short chains

Gram-positive

Spores: Produces highly resistant endospores, allowing survival in extreme conditions

Irregular, spreading edges

Medium to large (2-3 mm in diameter)

Off-white, cream, or light yellow

Dry & Wrinkled (due to biofilm production)

Mucoid

-If encapsulated strains are present

-Sticky & Stringy - Due to extracellular matrix production

Beta-hemolytic

Facultative anaerobe

Antibiotic resistance concerns:

Naturally resistant to some antibiotics (e.g., penicillins) due to spore-forming abilities

Some strains are used as probiotics in gut health supplements

B. subtilis is used in biotechnology to produce enzymes (e.g., amylase, protease) for detergents

and food processing