Conventional and molecular identification of methicillin-resistance Staphylococcus aureus (MRSA) associated with human skin lesions and bovine mastitis

Background. The objective of this study was to identify the prevalence of Staphylococcus aureus (S. aureus) taken from human skin lesions and bovine mastitis samples as well as determine the rate of occurrence of methicillin-resistance S. aureus (MRSA) and to analysis of the genetic connections between isolated bacteria with local and global strains. Methods. A total of 350 specimens were collected, including 150 specimens from human with different skin lesions and 200 specimens from cattle with mastitis. Results. Cultivation methods and biochemical evaluation demonstrated the presence of 86 (57.3%) and 98 (49%) S. aureus isolates in human and animal samples, respectively. The resistance pattern showed that each individual S. aureus isolate shown resistance to penicillin. (100%) followed by erythromycin (86% and 95.5%), Clindamycin (69.7% and 90.8%), Oxacillin (63.9% and 82.6%), Levofloxacin (50% and 55.1%), Tetracyclin (19.7% and 12.2%), Vancomycin (15.1% and 9.1%), Teicoplanin (8.1% and 20.4%) and Gentamicin (9.3% and 5.1%) for human and animals, respectively. The mecA gene was detected in all human Oxacillin resistant isolates (100%), while it was detected only in 73 (82.6) phenotypically Oxacillin resistant isolates. PCR partial gene sequencing that targeted housekeeping gene loci; arcC, aroE, glpF, gmk, pta, tpi, and yqi was done. The sequences were analyzed using multilocus sequence typing (MLST). These isolates carried the above-mentioned genes as follows; 2 (6.7%), 2 (6.7%), 2 (6.7%), 2 (6.7%), 6 (6.7%), 3 (10%), and 2 (6.7%) human isolates, and 10 (13.3%), 14 (18.7%), 8 (10.7%), 6 (8%), 10 (13.3%), 3 (4%), and 2 (2.7%) for milk isolates, respectively, and the MLST via a phylogenetic evaluation revealed close-nucleotide similarities between local and NCBI-based human and cow sequences. Conclusion. Ultimately, the findings of the current investigation suggest that S. aureus is commonly identified in human skin lesions and milk samples and a lot of these isolates the bacteria included significant resistance genes, identifying a possible origin of the spread of resistance to human strains. Furthermore, the obtained information about the genetic similarities between these isolates highlights the animals as an important source for transporting the virulent pathogens to human which leads to health risks to public health.