RESUMO
A prevalent bacterial intestinal infection with severe economic damage is salmonellosis. Our study was carried out to diagnose Salmonella from chickens and calves, to determine its resistance to antimicrobials' phenotypic and genotypic characterization of integrons and ß lactamase genes in the multidrug resistance of different Salmonella serotypes, and to detect the genetic relationship between Salmonella isolates collected from different origins using an ERIC PCR. In total, 200 samples from diseased chicken and diarrheic calves were obtained from 50 various farms from Kafr El-sheikh, Egypt. Salmonella poultry isolates were characterized as S. Typhimurium (3/8), S. Enteritidis (3/8), and S. Kentucky (2/8), but Salmonella isolates from cattle were S. Enteritidis (1/2) and S. Kentucky (1/2). When antibiotic susceptibility testing was completed on all of the isolates, it showed that there was multidrug resistance present (MDR). A PCR was applied for identifying the accompanying class 1 integrons and ESBLs from MDR Salmonella isolates (two isolates of S. Kentucky were divided as one from calf and one from poultry). Our results detected blaTEM and class 1 integron, but were negative for bla IMP, bla VIM, and bla SHV. An ERIC PCR was conducted for understanding the clonal relation between various ß-lactamase-producing MDR Salmonella isolates. The same four previously mentioned isolates were also tested. The two isolates of S. Enteritidis isolated from poultry and calves had 100% similarity despite indicating that there were interactions between broilers and calves living on the same farm that caused infection from the same Salmonella strains, while the other two isolates of S. Kentucky showed only 33% serovarities.
RESUMO
The increase in multidrug-resistant Salmonella enterica and its spread from food to humans are considered a serious public health concern worldwide. Little is currently known about the prevalence of extended-spectrum ß-lactamase (ESBL)-producing S. enterica in fish in Africa. Therefore, this study aimed to investigate the existence of ESBL-producing S. enterica in retail fish in Egypt. In total, 200 fish samples were collected randomly from various retail fish markets in Egypt. S. enterica were detected in 19 (9.5%; 95% CI: 5.8-14.4) of the fish samples analyzed. Of the 19 non-repetitive S. enterica isolates, 18 were serologically categorized into eight S. enterica serovars and a non-typable serovar. All 19 S. enterica isolates (100%) showed multidrug-resistant phenotypes to at least three classes of antimicrobials, and 11 (57.9%) exhibited an ESBL-resistant phenotype and harbored at least one ESBL-encoding gene. The ESBL-producing S. enterica serovars were as follows: Kentucky (3 isolates; 15.8%), Enteritidis (2 isolates; 10.5%), Typhimurium (2 isolates; 10.5%), and 1 isolate (5.3%) each of Infantis, Virchow, Paratyphi B, and Senftenberg. The identified ß-lactamase-encoding genes included ESBL-encoding genes blaCTX-M-3, blaCTX-M-14, blaCTX-M-15, blaSHV-1, blaSHV-2 and blaSHV-12; the AmpC ß-lactamase-encoding gene blaCMY-2; and the narrow-spectrum ß-lactamase-encoding genes blaTEM-1 and blaOXA-1. All S. enterica isolates were negative for carbapenemase-encoding genes. Molecular analysis of plasmid transferability and replicon typing revealed that most plasmids (with ß-lactamase-encoding genes) were transferrable, and the most common incompatibility groups were IncI1, IncA/C, IncHI1, and IncN. To the best of our knowledge, this is the first report for molecular characterization of ESBL-producing S. enterica in fish in Egypt. The occurrence of ESBL-producing S. enterica in retail fish constitutes a potential public health threat with the possibility of transmission of these strains with resistance genes to humans. Such transmission would exacerbate the resistance to an important class of antibiotics commonly used in hospitals to treat typhoid and non-typhoidal Salmonella infections.
