Characterization of Bacillus amyloliquefacien contaminating 75% alcohol disinfectant

The clinical characterization of Bacillus amyloliquefacien contaminating 75% alcohol disinfectants were studied. The bacteria were cultured and observed by using bacterial examination under the hospital infection monitor. According to the regulations, the resistance of bacterial to physical and chemical factors was tested. Drug sensitivity tests for 20 commonly used medicines were carried out using a K-B method. The bacterial plasmids were analyzed using the Birnboim method. The bacteria were found after being cultured in the clinically-used 75% alcohol disinfectant fluid. Their total number was more than 800 cfu/mL and they were identified as Bacillus amyloliquefacien. The bacteria were also found to be resistant to boiling for 5 min. It grew well in 95% alcohol disinfectant and was insensitive to 84 disinfectant fluids containing chlorine (1000 mg/L) and such disinfectants as ozone. They were able to be sterilized better through routine ultraviolet exposure for 30 min or gas pressure. The bacteria contained a 2.5 kb plasmid and were sensitive to 13 drugs and insensitive to 7 drugs of the 20 drugs tested. It was suggested that alcohol disinfectant fluid was easily contaminated by Bacillus amyloliquefacien, and the bacteria was resistant to disinfectant fluids such as alcohol and 84 disinfectants.