Premium
Transfer of ampicillin resistance from Salmonella Typhimurium DT104 to Escherichia coli K12 in food
Author(s) -
Walsh C.,
Duffy G.,
Nally P.,
O’Mahony R.,
McDowell D.A.,
Fanning S.
Publication year - 2008
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2007.02288.x
Subject(s) - escherichia coli , microbiology and biotechnology , ampicillin , biology , bacteria , amp resistance , plasmid , salmonella , enterobacteriaceae , strain (injury) , antibiotic resistance , antibiotics , gene , genetics , anatomy
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 log 10 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 , log 10 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 nal R transconjugant strain revealed the presence of a newly acquired plasmid (21 kbp) bearing the β‐lactamase gene bla TEM . 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.