TRIAL EVALUATION OF TOXICITY AND PATHOLOGY IN MURINE TISSUES USING BACILLUS SPHAERICUS COLOMBIAN STRAIN

Colombian isolate Bacillus sphaericus OT4b25 was tested for toxicity and pathology on rabbits and mice as mammalian models. After a high single dose of microorganism (108-109 spores/ml) in four different tests that included dermal, inhalatory, oral, and intraperitoneal routes of administration, subsequent daily observations were performed and weekly body weight was measured. In the oral and intraperitoneal routes infectivity was evaluated by a gross necropsy at interim or final sacrifice, recovering the microorganism both from organs and from peripheral blood. In the oral test, clearance of microorganism was estimated in feces and in the inhalatory test it was estimated from lungs. In both tests a decrease of the recovered microorganism was observed in time. Even though in the oral test recovery of the microorganism from the liver, spleen and lungs and additionally in the intraperitoneal from caecum and injection site was observed, it was not recovered from blood and brain in both tests. Although a persistence of the microorganism in animals was observed after oral, inhalatory and intraperitoneal routes of administration, no animals died or showed lesions during each test, and the body weight was not affected compared with the control groups. In conclusion, at the conditions and doses tested Bacillus sphaericus OT4b25 is not toxic or pathogenic following dermal, oral, inhalatory, and intraperitoneal routes of administration.