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Mechanisms of resistance to quaternary ammonium compounds and other antimicrobials in Salmonella enterica
Author(s) -
Stamm Sarah,
Herson Diane
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.799.5
Subject(s) - salmonella enterica , efflux , microbiology and biotechnology , antimicrobial , salmonella , antibiotics , strain (injury) , antibiotic resistance , ammonium , downregulation and upregulation , minimum inhibitory concentration , biology , multiple drug resistance , gene , drug resistance , bacteria , chemistry , genetics , organic chemistry , anatomy
Each year nearly 1.4 million people in the United States are infected with Salmonella as a result of food poisoning. Antimicrobials are used for both the prevention and treatment of salmonellosis, and a major concern is that resistance to these agents will develop. Salmonella enterica Strains with Reduced Susceptibility (SRS) to Quaternary Ammonium Compounds (QAC) were generated by repeatedly passaging strains in increasing concentrations until a Minimum Inhibitory Concentration (MIC) of 400 ppm was obtained. DSRS strains were generated by culturing SRS stains in the absence of the agent until their MIC returned to that of the parent strain. Parent, SRS, and DSRS strains were tested for cross resistance to four antibiotics. Strains were then tested for efflux pump activity by qPCR analysis of the acrB and marA genes. Unlike DSRS, SRS strains showed cross resistance to all four antibiotics. These strains showed upregulation of the acrB gene while DSRS showed expression similar to the parent strains. For marA gene expression, both SRS and DSRS strains showed upregulation compared to the parent strain. This project was funded by Howard Hughes Medical Institute.