Methicillin-Resistant Staphylococcus aureus from Municipal Abattoirs in Nigeria: Showing Highly Similar Clones and Possible Transmission from Slaughter Animals to Humans

Abstract

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has gained interest in veterinary medicine due to its zoonotic potential. Currently, little information is available on the genotypic and virulence characteristics of MRSA isolates detected in Nigerian abattoirs. To better understand the epidemiology of MRSA associated with the abattoir food chain environment in Nigeria, a total of 18 isolates (humans: n = 5, slaughter animals: n = 5, and environment: n = 8), previously spa typed, were recovered and characterized by Staphylococcus cassette chromosome mec (SCCmec) typing, and phenotypic and genotypic antimicrobial susceptibility testing. In addition, 10 of the 18 MRSA strains with a new spa type (t16571) were subjected to multilocus sequence typing. The similarity of strains was analyzed based on the results of the DNA microarray analysis. The 18 MRSA strains harbored two distinct SCCmec types (IVa and V) and belonged to four clonal clusters (CC1, CC7, CC88, and CC152). All MRSA of the new spa type t16571 (n = 10) harbored the SCCmec type IVa. Seven of the MRSA t16571 strains belonged to ST88, while three other strains were assigned to ST3614. The 18 MRSA isolates were categorized into six virulence profiles, and the detection rate for the Panton–Valentine Leukocidin gene was high (33.3%). The antimicrobial susceptibility profiles of the 18 MRSA varied widely between strains, but phenotypic resistance corresponded to relevant resistance genes harbored. The detection of highly similar MRSA strains in slaughter animals, abattoir workers, and the environment underlines the need to use adequate measures at Nigerian abattoirs to prevent further spread and transmission of MRSA to humans or food.