Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major threat to public health. This study investigated the occurrence of MRSA in humans, chickens, chicken meat and environmental samples within poultry farms and live bird markets in southwestern Nigeria. Methods: MRSA were isolated using selective culture and tested for antimicrobial susceptibility by broth microdilution. Selected isolates were characterized by whole genome sequencing (WGS). From WGS data, spa, dru, multilocus sequence typing (MLST) and SCCmec types, but also virulence and antimicrobial resistance genes, were identified. Results: Fifty-six MRSA isolates were detected in 734 samples. They showed resistance to β-lactams (100%), tetracycline (60.7%), ciprofloxacin (33.9%), erythromycin (28.6%), gentamicin (32.1%), and trimethoprim/sulfamethoxazole (10.7%). All 30 isolates investigated by WGS carried mecA, dfrG, and tet(38) genes. Other resistance genes detected were blaZ (83.3%), fosB (73.3%), tet(K) (60.0%), aacA-aphD (36.6%), aphA3 (33.3%), msr(A) (30.0%), mph(C) (30.0%), dfrS1 (3.3%), and sat4 (3.3%). Seven spa types (t091, t314, t657, t1476, t2331, t4690 and t12236), four known (dt9aw, dt10ao, dt10cj, and dt11a) and two novel (dt10dr and dt11dw) dru types, as well as five sequence types (ST8, ST121, ST152, ST772 and ST789) were found among the MRSA isolates. All ST121 isolates carried an SCCmec type IV cassette and were not dru-typeable. ST152 and ST121 were found only in specific sample categories within defined locations, while ST8 and ST772 were distributed across most sample categories and locations. Three SCCmec types, IVa, V and Vc, were identified. All MRSA isolates possessed virulence genes including aur, clpP, coa, fnbA, esaA, hly, hla, ica, isdA, srtB, sspA, and vWbp, among others. The toxic shock syndrome toxin gene (tst) was not detected in any isolate, whereas the Pantone–Valentine leukocidin genes lukF-PV/lukS-PV were present in all ST121, all ST772, and all but one ST152 isolates. Conclusion: The results of this study (i) showed that chicken meat is contaminated by MRSA and (ii) suggested that live bird markets may serve as focal points for the dissemination of MRSA within the community.

Lycopersicon esculentum (tomato) is a fleshy berry that is highly perishable and prone to microbial spoilage. The presence of some microorganisms of public health significance makes it a potential health hazard to consumers. There is therefore the need to determine the food safety and public health implications of some of the microorganisms present in it. The aim of the study was to isolate, identify and compare the incidence of the organisms that could be potential pathogens among the four grades of tomato samples used in the investigation. Seven batches of tomato samples were obtained from two (2) major produce markets in Lagos Nigeria. A total of 40 isolates were obtained from the tomato samples. Staphylococcus aureus (22.5%), Escherichia coli (15%), Bacillus species (20%) and Salmonella species (5%) were among the bacteria isolated from the tomato samples. The average pH values of the tomato samples ranged from 4.34 to 4.60 while the average moisture content of the tomato samples was between 12% and 95.1%. The results showed that the freshness and hardness of tomato samples were important factors which determine the types of bacteria found on them. As some of the bacterial genera identified are potential food-borne pathogens that could pose some public health challenges, proper handling and adequate cooking before consumption is suggested