With the rising prevalence of methicillin-resistant Staphylococcus (S.) aureus (MRSA), a multi drug resistant strain, treatment has become a challenge. The infection frequently involves the skin and soft tissue, but it can also cause other life-threatening systemic illnesses including endocarditis, meningitis, and toxic shock syndrome.

Methicillin-resistant_Staphylococcus_aureus_(MRSA)_Bacteria

Source: NIAID/NIH

Scanning electron micrograph of methicillin-resistant Staphylococcus aureus(MRSA, brown) surrounded by cellular debris.

The known antibiotic resistance determinants, mecA and mecC, detected in MRSA isolates exhibit a broad spectrum of cross-antibiotic resistance. This study identified three functional protein families, through sequencing, that confer extensive antibiotic resistance independent of mecA and mecC. Twenty-six isolates had their DNA sequenced for mepR, mepA, mepB, and sapep genes for correlation with their antimicrobial phenotypes. 

Transcriptional profiling revealed that both animal and human MRSA isolates exhibited a gene cluster mepRAB (multidrug export protein gene), encoding a MarR-like transcriptional regulator (mepR), a M20/M25/M40 metallo-hydrolase protein gene (sapep) encoding resistance to biocides and carbapenems, and a hypothetical protein gene of unknown function (mepB).

The work entitled “Genetic resistance factors and antimicrobial resistance phenotypes in methicillin-resistant Staphylococcus aureus isolates of animals and humans” was published in One Health Bulletin (published on Jan. 23, 2025).

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