Isolation and identification of multidrug–resistant Staphylococcus haemolyticus from a laboratory–breeding mouse

ObjectiveTo analysis and identify a bacterium strain isolated from laboratory breeding mouse far away from a hospital.MethodsPhenotype of the isolate was investigated by conventional microbiological methods, including Gram–staining, colony morphology, tests for haemolysis, catalase, coagulase, and antimicrobial susceptibility test. The mecA and 16S rRNA genes were amplified by the polymerase chain reaction (PCR) and sequenced. The base sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank database by phylogenetic analysis and multiple sequence alignment.ResultsThe isolate in this study was a gram positive, coagulase negative, and catalase positive coccus. The isolate was resistant to oxacillin, methicillin, penicillin, ampicillin, cefazolin, ciprofloxacin erythromycin, et al. PCR results indicated that the isolate was mecA gene positive and its 16S rRNA was 1 465 bp. Phylogenetic analysis of the resultant 16S rRNA indicated the isolate belonged to genus Saphylococcus, and multiple sequence alignment showed that the isolate was Saphylococcus haemolyticus with only one base difference from the corresponding 16S rRNA deposited in the GenBank.Conclusions16S rRNA gene sequencing is a suitable technique for non–specialist researchers. Laboratory animals are possible sources of lethal pathogens, and researchers must adapt protective measures when they manipulate animals.