Occurrence and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus in fresh milk and milk products in Nasarawa State, North-Central Nigeria

Abstract

Methicillin resistant Staphylococcus aureus (MRSA) keeps emerging as a pathogen of significant public health concern. In this study, the occurrence and antibiogram of MRSA from fresh milk and milk products sold in Nasarawa State, north-central Nigeria, were determined. A total of 180 samples comprising of fresh milk, bulk milk, nono and kindirmo were collected and examined for the presence of antibiotic-resistant phenotypes of MRSA using standard microbiological procedures and molecular confirmation using species-specific 23S rDNA Polymerase chain reaction (PCR). Also, the presence of mecA gene was determined from confirmed MRSA strains using PCR. The cumulative occurrence of MRSA as obtained from this study was 5.00% (9/180); with 7.14, 6.06, 4.55 and 2.94% occurrence in bulk milk, nono, kindirmo and fresh milk respectively. With respect to the sampling locations, 2.86, 6.89, 7.14, 3.57, 6.45 and 3.45% occurrence of MRSA were recorded from Nasarawa, Keffi, Akwanga, Wamba, Lafia and Doma local government areas respectively. There was no significant difference (P>0.05) in the occurrence of MRSA in both the sample types and sampling locations. All the 9 MRSA strains examined showed 100% resistance to ampicillin and amoxicillin/clavulanic acid. This study recorded 5 antibiotic resistance patterns among theMRSA strains with multiple antibiotic resistance (MAR) index of 0.3 and above. Only 3 of the 9 MRSA strains isolated harboured mecA gene. This study provides baseline data on the public health risks associated with the consumption of milk products sold in Nasarawa State, Nigeria.