The incidence of extended spectrum beta-lactamase (ESBL)-producing pathogens is worrisome because it confers multiple drug resistance (MDR). Considering their serious clinical significance, the study investigated the prevalence of MDR-ESBL-producing Salmonella strains isolated from raw chicken meat in Southern Nigeria. A total of 240 raw chicken meat were sampled and the recovered Salmonella strains were characterized for MDR and ESBL-genes using Kirby Bauer disc diffusion and molecular techniques. Of the 52 confirmed Salmonellaenterica serotypes, 67.31% (35/52) were Salmonella entericasubsp. entericaserovar Typhimurium, 32.68% (17/52) were Salmonella entericasubsp. entericaserovar Enteritidis, 78.85% (41/52) were ESBL-producer and 88.45% (46/52) multidrug resistant. Ampicillin (96.15%) and gentamycin (40.39%) were the most and least antibiotics. The most prevalent MDR-ESBL-genes were bla CTX-M (92.68%), followed by bla SHV genes (68.29%) and bla TEM(31.71%). This study showed that Salmonella serotypes with high ESBL-genes and MDR were prevalent in raw chicken meat vended in southern Nigerian markets. Bangladesh J. Sci. Ind. Res.56(4), 271-284, 2021

Available data showed that the recovery of multidrug-resistant and biofilm-producing Salmonella spp. from chicken meat is still scanty in Nigeria. Consequently, this study aimed to characterize the probable multidrugresistant and biofilm producing Salmonella spp. prevalent in chicken meat vended in southern Nigerian markets. About 240 randomly sampled chilled raw chicken meats were collected from open markets in Delta, Edo, Ekiti and Ondo States, and then were analysed for detecting the presence of Salmonella spp.; using rinse centrifugation-plating technique, serological examination and 16S rRNA gene sequencing. The confirmed Salmonella isolates were tested for multidrug-resistance and biofilm formation using Kirby Bauer disc diffusion test and tissue culture plates, respectively. Out of 229 presumptively examined Salmonella isolates, 52 isolates were confirmed as Salmonella spp., while 46 isolates were recorded as multidrug-resistant. The main serotypes recovered were; S. enterica subsp. enterica serovar Typhimurium (35/52; 67.31%), and S. enterica subsp. enterica serovar Enteritidis (17/52; 32.69%). Biofilm characterization of the recovered Salmonella isolates were; strong (OD > 0.240), 6 (11.5 %); moderate (0.120-0.240), 13 (25.0 %); weak (OD < 0.120), 19 (36.5 %), and nonbiofilm producers (OD < 0.120), 14 (26.9 %). This study showed that multidrug-resistant and biofilm-producing Salmonella spp. were prevalent in raw chicken meat; vended within southern Nigerian open markets. Thus, there is an urgent need for relevant regulatory agencies to enforce consumer's safety.