Bacillus spp. are spore forming bacteria, ubiquitous in the environment. B. cereus in particular is a frequently recognized cause of toxin-induced acute gastroenteritis.

Other infections caused by this genus include:

- sepsis

- pneumonia

- endocarditis

- central nervous system (CNS) and ocular infections

Epidemiology:

Bacillus organisms are widely distributed in the environment although the primary habitat is the soil. These organisms are usually found in decaying organic matter, dust, vegetable, water, and some species are part of the normal flora.

In the hospital setting, outbreaks and pseudo epidemic have been traced to contaminated ventilator equipment, disinfectant (ethyl alcohol), hospital linen and dialysis equipment. Sources of B. cereus in food borne outbreaks have been described including rice, meat loaf, turkey loaf, mashed potatoes, beef stew, apples and hot chocolate sold in vending machines.

The clinical spectrum of infections caused by Bacillus spp. include self limited food poisoning, localized infections related to trauma (e.g. ocular infections), deep seated soft tissue infections, and systemic infections (e.g. meningitis, endocarditis, osteomyelitis, and bacteremia).

Fulminant eye infections are widely recognized complications of non anthrax Bacillus infections most commonly B. cereus. The various species implicated in serious infections include B. cereus, B. subtilis, B. sphaericus, B. alvei, B. laterosporus, B. licheniformis, B.megaterium and B. pumilus.

How can a Bacillus spp. outbreak be prevented?

The main preventative measure for gastroenteritis caused by B. cereus is proper food handling. The heat-resistant spores of B. cereus survive boiling and germinate when boiled rice is left unrefrigerated. Flash frying or brief rewarming of rice before serving is not adequate to destroy the preformed, heat-stable toxin. The food should either be maintained at a temperature higher than 60°C, or if it is going to be stored, should be cooled rapidly to a temperature below 8-10° to prevent growth or greatly reduce its rate.

There is currently no specific guidance on prevention of (non-foodborne) Bacillus spp.
infections.

References:

- Bacillus species, Authors: Carmelita U. Tuazon, M.D., M.P.H (http://www.antimicrobe.org/b82.asp)

- Risks for public health related to the presence of Bacillus cereus and other Bacillus spp. including Bacillus thuringiensis in foodstuffs (https://www.efsa.europa.eu/en/efsajournal/pub/4524)