Incidence and Resistotyping Profiles of Bacillus subtilis Isolated from Azadi Teaching Hospital in Duhok City, Iraq

BACKGROUND: Bacillus subtilis are opportunistic, spore forming bacteria, common soil inhabitants. A resistant spore allows bacteria to endure extreme conditions of heat and desiccation in the environments promotes their survival in many instances, even in environments like hospitals. OBJECTIVES: This paper purposes to find out the incidence of Bacillus subtilis from various sources at Azadi Teaching Hospital in Duhok city, Iraq. The susceptibility test and resistotyping (antibiotypes) profile of isolates were also studied. METHODS: During a period of eight months between Januarys to April, 2011, a total of 128 samples were collected from various sources and locations at Azadi Teaching Hospital in Duhok city. A sterile cotton swabs were used to collect the samples and analyzed by plating on Blood agar, Chocolate agar and MacConkey agar followed by the identification of the isolates based on their cultural characteristics and their reactions in standard biochemical tests. All the isolates were tested for antimicrobial susceptibility by the disk diffusion technique according to the Clinical and Laboratory Standards Institute guidelines on Muller Hinton Agar. RESULTS: Out of the 128 collected samples, 84 samples yielded bacterial growth, of them 31(24.2%) were Bacillus subtilis. Moreover, other bacterial groups were also isolated and identified. The results showed that the occurrence of Bacillus subtilis was higher than the other groups of bacteria. The susceptibility test of Bacillus subtilis isolates; the organism exhibited high susceptibility rate to gentamicin (96.7%) and ciprofloxacin (93.5%) While, cefotaxime (19.3%) and ampicillin (16.2%) demonstrated the lowest percentage of susceptibility rate. Resistotyping (antibiotypes) profiles of Bacillus subtilis isolates were determined. Out of 31 isolates, 22 of them were multiple resistant and belonged to 3 resistotype patterns; resistotype 1 was predominant among isolates. CONCLUSION: This study shows that there is an increased rate of incidence of Bacillus subtilis in hospital environments in study area and some of these isolates were multi-drug resistant and showed different resistotyping profiles.