Genome analysis of Salmonella strains isolated from imported frozen fish in Burkina Faso

Abstract

PurposeFish is an excellent source of protein and vitamins for humans, but improperly handled fish can expose consumers to pathogenic bacteria. This study aimed to isolate and characterize the genomes of Salmonella strains isolated from imported fish sold in the open market in Ouagadougou.MethodsOne hundred and fifty-nine fish were collected from open markets. Antimicrobial susceptibility was determined by broth microdilution. Whole Genome Sequencing was done to further study antibiotic resistance genes, plasmid replicons, and MSLT types. Serotyping was done using SeqSero 2.ResultOut of the 159 fish samples analyzed, 28 (17.61%) were found to be contaminated with Salmonella. Among the isolated Salmonella strains, 6 different serotypes, Nima, Liverpool, Kokomlemle, Gaminara, Derby, and Tennessee, were found using SeqSero2. S. Tennessee was the predominant serotype. All the isolates possessed at least one resistance gene. The aac6-Iaa and aac6-Iy conferring resistance to aminoglycosides was the most prevalent gene found in the strains. The gene fosA7 was detected in two. All the S. Nima isolates were of Multilocus Sequence Type (MLST) 2258, Gaminara was ST 5197; Liverpool was ST 1959; Derby was ST 3997; Kokomlemle was ST 2696. The serotype Tennessee isolates gave many different STs such as ST 3763; 3997; 3135.ConclusionThe presented results highlight the prevalence of Salmonella on imported fish purchased from the open markets. More attention should be paid regarding fish selling conditions in the country to prevent the potential health risk for consumers.