Enterococcus species form an important population of commensal bacteria and have been reported to possess numerous virulence factors considered significantly important in exacerbating diseases caused by them. The present study was designed to characterize antibiotic-resistant and virulent enterococci from ready-to-eat (RTE) seafood. A total of 720 RTE shrimp samples comprising sauced shrimp ( n = 288), boiled shrimp ( n = 216), and smoked shrimp ( n = 216) obtained from open markets in Delta State, Nigeria, were assessed. Standard classical methods and polymerase chain reaction (PCR) were used in identifying the Enterococcus species. Potential virulence factors (β-hemolysis, gelatinase activity, S-layer, and biofilm formation) were assessed using standard procedures. The antibiotic susceptibility profile of the identified enterococci isolates was assayed using the Kirby–Bauer disc diffusion method. PCR was further used to screen selected antibiotic resistance and virulence genes. Prevalence of Enterococcus species from shrimp varieties is as follows: sauced, 26 (9.03%); boiled, 6 (2.78%); and smoked, 27 (12.50%), with an overall prevalence of 59 (8.19%) based on the occurrence of black hallow colonies after incubation. Enterococcus species detected include E. faecalis , 17 (28.8%); E. faecium , 29 (49.2%); E. gallinarum , 6 (10.2%); E. casseliflavus , 2 (3.4%); E. hirae , 3 (5.1%); and E. durans , 2 (3.4%). Biofilm occurrence among the shrimp varieties is as follows: 19/26 (73.1%) for sauced shrimps, 5/6 (83.3%) for boiled shrimps, and 16/27 (59.3%) for smoked shrimps. The phenotypic expression of the enterococci virulence revealed the following: S-layer, 59 (100%); gelatinase production, 19 (32.2%); and β-hemolysis, 21 (35.6%). An average of 3–11 virulence genes were detected in the Enterococcus species. The resistance profile of Enterococcus species is as follows: erythromycin, 29 (49.2%); vancomycin, 22 (37.3%); and tetracycline, 27 (45.8%). The frequency of occurrence of antibiotic resistance genes from the phenotypic resistant enterococci isolates to the macrolide, glycopeptide, and tetracycline antibiotics is as follows: erm A, 13/29 (44.8%); van A, 14/22 (63.6%); tet A, 14/27 (51.9%); tet M, 15/27 (55.6%); erm B, 4/29 (13.8%); and van B, 5/22 (22.7%). Findings from this study reveal the antibiotic resistance of enterococci strains of such species as E. durans, E. casseliflavus, E. gallinarum , and E. hirae . This study further revealed that RTE food products are reservoirs of potential virul...

The emergence of antibiotic-resistant bacteria in food animals is a potential public health concern. Staphylococci are a significant opportunistic pathogen both in humans and dairy cattle. In the present study, the genotypic characterization of methicillin-resistant staphylococcal strains recovered from dairy cattle in a rural community (Okada, Edo State, Nigeria) was investigated. A total of 283 samples from cattle (137 milk samples and 146 nasal swabs) were assessed between February and April 2015. Antimicrobial susceptibility was performed by Kirby-Bauer disc diffusion method. Polymerase chain reaction (PCR) assay was employed for the detection of 16S rRNA, mecA and Panton-Valentine Leucocidinis (PVL) genes. The staphylococcal strains were identified through partial 16S ribosomal ribonucleic acids (rRNA) nucleotide sequencing, and Basic Local Alignment Search Tool (BLAST) analysis of the gene sequence showed that the staphylococcal strains have 96%–100% similarity to Staphylococcus aureus (30), S. epidermidis (17), S. haemolyticus (15), S. saprophyticus (13), S. chromogenes (8), S. simulans (7), S. pseudintermedius (6) and S. xylosus (4). Resistance of 100% was observed in all Staphylococcus spp. against MET, PEN, CLN, CHL and SXT. Multi-drug resistant (MDR) bacteria from nasal cavities and raw milk reveals 13 isolates were MDR against METR, PENR, AMXR, CLNR, CHLR, SXTR CLXR, KANR, ERYR, and VANR. Of all isolates, 100% harboured the mecA gene, while 30% of the isolates possess the PVL gene. All S. aureus harboured the PVL gene while other Staphylococcus spp. were negative for the PVL gene. The presence of methicillin-resistant Staphylococcus spp. isolates in dairy cattle is a potential public health risk and thus findings in this study can be used as a baseline for further surveillance.

The demand for minimally processed vegetables (African salad) has increased partly due to its inclusion in ready-to-eat foods. Nevertheless, the associated risk of the presence of emergent foodborne pathogens, such as Vibrio parahaemolyticus might be underestimated. The present study was designed to isolate and characterize foodborne V. parahaemolyticus from minimally processed vegetables using culture-based methods and molecular approach. A total of 300 samples were examined from retail outlets between November 2018 and August 2019 from Southern Nigeria. The prevalence of vibrios from the overall samples based on the colonial proliferation of yellow, blue-green and/or green colonies on thiosulfate citrate bile salts sucrose agar was 74/300 (24.6%). An average of two green or blue-green colonies from respective plates was screened for V. parahaemolyticus using analytical profile index (API) 20 NE. Polymerase chain reaction further confirmed the identity of positive V. parahaemolyticus. The counts of V. parahaemolyticus ranged from 1.5 to 1,000 MPN/g. A total of 63 recovered V. parahaemolyticus were characterized further. The resistance profile of the isolates include ampicillin 57/63 (90.5%), cefotaxime 41/63 (65.1%), ceftazidime 30/63 (47.6%), amikacin 32/63 (50.8%), kanamycin 15/63 (23.8%), and oxytetracycline 16/63 (25.4%). The multiple antibiotic index ranged from 0–0.81. The formation of biofilm by the isolates revealed the following: strong formation 15/63 (23.8%), moderate formation 31/63 (49.2%), weak formation 12/63 (19.1%), and no formation 5/63 (7.9%). A total of 63/63 (100%), 9/63 (14.3%), and 20/63 (31.8%) of the isolates harbored the tox R gene, TDH-related hemolysin (trh) and thermostable direct hemolysin (tdh) determinants respectively. The isolates with O2 serogroup were most prevalent via PCR. Isolates that were resistant to tetracycline, kanamycin, and chloramphenicol possessed resistant genes. The presence of multidrug-resistant vibrios in the minimally processed vegetables constitutes a public health risk and thus necessitates continued surveillance.

Gastrointestinal illnesses continue to be a global public health risk. Exposure to foodborne Salmonella directly or indirectly through consumption of ready-to-eat seafood can be an important route of infection to humans. This study was designed to estimate the population cell density, prevalence, virulence gene signatures, and antibiotic resistance of Salmonella serovars from ready-to-eat shrimps. Ready-to-eat (RTE) shrimp samples were obtained from different open markets in Delta and Edo States, Nigeria from November 2016 to October 2017. We employed classical and polymerase chain reaction (PCR) approaches. The mean Salmonella species enumerated from the RTE shrimps ranged from −0.301 to 5.434 log 10 cfu/g with 210/1440 (14.58%) of the RTE shrimp samples harbored Salmonella species. After biochemical and PCR approach, the identified isolates were Salmonella Enteritidis 11(24.4%), Salmonella Typhimurium 14 (31.1%) and other Salmonella spp. 20 (44.4%). All Salmonella species recovered were resistant to penicillin and erythromycin with 100% sensitivity to cefotaxime, cephalothin, colistin, and polymyxin B. Findings on the multidrug-resistant (MDR) profile showed that a total of 9/14 (64.3%) of Salmonella Enteritidis were resistant to 5 antibiotics which belongs to 3 different groups of antimicrobials with a multiple antibiotic-resistant (MAR) index of 0.21; while 3/11 (27.3%) of Salmonella Typhimurium were resistant to 11 antibiotics which belongs to 7 different groups of antimicrobials with a MAR index of 0.46. Virulence genes ( spi A, sip B, inv A, sif A, flj B, and sef A) and resistance genes (class 1 and II integrase, sul 2, catB 3, flor, tmp, bla TEM , str B, dfr 1, and tet C) were also detected in some of the Salmonella species with variable percentage. This study indicates that ready-to-eat shrimps are probable reservoirs harboring Salmonella strains. The identified Salmonella isolates which exhibited virulence determinants and antibiotic-resistant coupled with high MAR index constitute a consumer health risk to the communities.