MOLECULAR EPIDEMIOLOGY OF STAPHYLOCOCCUS AUREUS ISOLATED FROM MICE. A STUDY OF ANTIBIOTIC RESISTANCE AND GENETIC DIVERSITY USING 16S-rRNA A GENE SEQUENCING

Abstract

Staphylococcus aureus is a clinically significant pathogen with increasing antibiotic resistance and zoonotic potential. In the current study total of bacterial strains of S. aureus strains were isolated from swab samples of mice. The isolates were then characterized on the basis of their morphology and microscopic analysis. Biochemical characterization was conducted to characterize isolates of pathogens. All strains are classified and characterized as Staphylococcus aureus by giving round, smooth, and slightly raised cream to golden yellow colonies on Mannitol salt agar. Biochemical characterization was conducted to characterize isolates of pathogens. The biochemical test results show that isolates don’t react with coagulase, oxidase, methyl red test and motility test and did react with catalase test. Using 16S rRNA gene sequencing, this study further investigated the  genetic diversity, antibiotic resistance trends, and molecular epidemiology of S. aureus isolates isolated from mice. Following the extraction of genomic DNA from bacterial isolates, PCR amplification and 16S rRNA gene sequencing were conducted. Phylogenetic reconstruction using MEGA X and  bioinformatics analysis, such as BLAST, confirmed species identification and  demonstrated evolutionary links with other isolates of S. aureus. Resistance profiles were evaluated through the use of antibiotic susceptibility testing. The findings showed substantial grouping in the phylogenetic tree and strong genetic similarity (98.37%) to known S. aureus strains, indicating potential host adaptability or environmental selection pressures. Concerns over antibiotic resistance in zoonotic strains were also raised by the observation of diverse resistance patterns. The study expands the understanding of S. aureus epidemiology and its possible consequences for public health and laboratory animal management by shedding light on the genetic diversity and antibiotic resistance of the bacteria in mice