Transfer of ampicillin resistance from Salmonella Typhimurium DT104 to Escherichia coli K12 in food

Abstract

Aims: To investigate the transfer of antibiotic resistance from a donor Salmonella Typhimurium DT104 strain to a recipient Escherichia coli K12 strain. Methods and Results: Mating experiments were conducted in broth, milk and ground meat (beef) at incubation temperatures of 4, 15, 25 and 37°C for 18 and 36 h. Ampicillin‐resistance transfer was observed at similar frequencies in all transfer media at 25 and 37°C (10−4 to 10−5 log10 CFU ml g−1, transconjugants per recipient) for 18 h. At 15°C, transfer was observed in ground meat in the recipient strain (10−6, log10 CFU g−1, transconjugants per recipient), but not in broth or milk. At 4°C, transfer did not occur in any of the examined mediums. Further analysis of the E. coli K12 nalR transconjugant strain revealed the presence of a newly acquired plasmid (21 kbp) bearing the β‐lactamase gene blaTEM. Transconjugants isolated on the basis of resistance to ampicillin did not acquire any other resistant markers. Conclusion: This study demonstrates the transfer of antibiotic resistance in food matrices at mid‐range temperatures. Significance and Impact of the Study: It highlights the involvement of food matrices in the dissemination of antibiotic‐resistant genes and the evolution of antibiotic‐resistant bacteria.

Comparison of phenotypic and genotypic antimicrobial profiles in Escherichia coli and Salmonella enterica from the same dairy cattle farms

“…The success of antibiotic resistance gene transfer between these species then would depend on mechanism of exchange. For example, conjugative transfer of donor plasmid from Salmonella enterica serovar Typhimurium DT104 strain to a recipient Escherichia coli K12 strain has demonstrated [10]. Such plasmid mediated mechanisms could account for the similarities in resistance gene profile found in our study.…”

“…For example, E. coli and Salmonella are closely related members of enterobacteriaceae sharing a common ancestor that diverged roughly 150 million years ago[9]. In vitro experiments have demonstrated that ampicillin resistance could be transferred from Salmonella enterica serovar Typhimurium DT104 to E. coli K12 [10]. However such studies do not accommodate the complexity of microbial systems in nature under which such transfers take place.…”

Antimicrobial Resistance in the Food Chain: A Review

“…Conjugation in food matrices was reported in experimental studies e.g., the transfer of plasmid-borne ampicillin resistance genes from Salmonella Typhimurium to E. coli K12 in inoculated sterilized milk and ground beef [70] and the transfer of antimicrobial resistance from lactic acid bacteria (LAB) ( Enterococcus faecalis , Lactococcus lactis ) to potential pathogenic strains ( Listeria spp., Salmonella spp., Staphylococcus aureus and E. coli ) in fermented whole milk (fermented with the LAB donors) [71]. Van der Auwera et al [72] found significant levels of conjugation and mobilization of plasmids between strains of Bacillus thuringiensis in milk and rice pudding.…”

Antimicrobial profile of Salmonella enterica serotype Choleraesuis from free-range swine in Kakamega fish market, western Kenya

“…Several authors have implicated the misuse of antimicrobials or the mobile genetic elements of bacteria (plasmids, transposons, and integrons) as the cause of widespread antimicrobial resistance [42][43][44], but this has now changed due to the generic nature by which different strains acquire the resistance genes. The ability of integrons to excise and integrate resistance gene cassettes from the environment or other bacteria have given them a cardinal role in antimicrobial resistance in bacteria [45][46][47][48]23]. Integrons have been identified among clinical isolates, in farm animals, and in aquatic environments [49].…”