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A total of 405 Escherichia coli from the chicken production chains in Nigeria were investigated for ESBL-production and 4 isolates were identified as ESBL producers. They were characterized by XbaI-PFGE, multilocus sequence typing (MLST), phylotyping, sequencing of porin and regulatory genes and of the regulatory region of chromosomal ampC genes. Transformed ESBL gene-carrying plasmids were characterized by S1-nuclease, replicon typing, conjugation, digestion and PCRs for detection of the genetic environment of ESBL genes. Susceptibility testing, PCRs for the resistance genes, integrons, and the DNA microarray were performed with both, the original isolates and the transformants. All ESBL-producing isolates harboured bla CTX-M-15 genes located on non-conjugative plasmids (120–155 kb). Three isolates with closely related/indistinguishable XbaI-patterns belonged to phylogroup A, and MLST sequence type ST10 and the fourth to phylogroup D and ST405. Resistance to aminoglycosides, sulfonamides/trimethoprim, quinolones, and tetracyclines were seen in all isolates. Incompatibility group IncFIB bla CTX-M-15 -carrying plasmids were detected in the three related isolates which carried also a class 1 integron ( aadA2 -orfF- dfrA12 ) and the resistance genes bla OXA-1 , bla TEM-1 , aac(3′)-IIa , aac(6′)-Ib-cr , sul1 , sul2 , and tet (A). The IncFIA-IncFIB-IncI1 bla CTX-M-15 -carrying plasmid harboured additionally the resistance genes aac(3′) - IIa and tet (B). The bla CTX-M-15 genes were associated with IS Ecp1 and Δorf477. ESBL-producing isolates showed elevated MICs to cefoxitin (16–64 mg/L) and ertapenem MICs (0.5–2.0 mg/L) mainly due to alterations in the porin genes. The virulence genes astA and prfB were detected. Although a low prevalence of ESBL-producing isolates was found, co-located resistance genes on the ESBL gene-carrying plasmids may facilitate the dissemination of them. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study examined socioeconomic and cultural factors relating to animal husbandry, antimicrobial usage and household hygiene in 320 animal-keeping households of 16 rural and peri-urban communities of Ogun State, Nigeria. The occurrence of extended-spectrum β-lactamase-producing Enterobacteriaceae in 457 samples from animal and environmental sources within the households was investigated. Chickens (41.6%), goats (35.3%), dogs (33.8%) and sheep (14.4%) were the most common household animals. Animals were reared mainly for income generation (73.9%) and for household consumption (18.3%). They were reared predominantly (60.2%-100%) under the extensive system with unrestricted access to human space, cooking utensils and foods. Households were assessed as having good (59.4%), fair (22.2%) and poor (18.4%) hygiene. The rate of household non-prescriptional antimicrobial usage was 69.4% in humans and 60.6% in animals. Overall, ESBL-producing Enterobacteriaceae were detected in 53 (11.6%) of 457 samples. The ESBL-producing isolates were identified as Escherichia coli (n = 49) and Klebsiella pneumoniae (n = 4). They harboured the ESBL gene variants bla CTX-M-15 (n = 49), bla CTX-M-14 (n = 2), bla CTX-M-27 (n = 1) or bla CTX-M-55 (n = 1). Forty-eight ESBL-producing E. coli were assigned into phylogenetic groups A (n = 17), B1 (n = 14), D (n = 13) and F (n = 4). All ESBL-producing isolates demonstrated multidrug resistance to antimicrobial agents belonging to at least three different classes of antimicrobials. Poor regulation of antimicrobial marketing and inadequate access to veterinary care contributed to non-prescriptional use of antimicrobials in humans and animals. Free-range household animals harboured ESBL-producing bacteria and may facilitate the dispersal of the organisms within the community., (Copyright © 2018 Elsevier B.V. All rights reserved.)