title: Modelling of tetracycline resistance gene transfer by commensal Escherichia coli food isolates that survived in gastric fluid conditions.
abstract: Antimicrobial resistance (AR) is a major public health concern and a food safety issue worldwide. Escherichia coli strains, indicators of antibiotic resistance, are a source of horizontal gene transfer to other bacteria in the human intestinal system. A probabilistic exposure model was used to estimate the transfer of the AR gene tet(A). The acid resistance and kinetic behaviour of E. coli was analysed as a function of pH to describe the inactivation of E. coli in simulated gastric fluid (SGF), the major host barrier against exogenous micro-organisms. The kinetic parameters of microbial inactivation in SGF were estimated using GInaFiT, and log-linear + tail and Weibull models were found to be suitable for commensal and enterohaemorrhagic E. coli (EHEC), respectively. A probabilistic exposure model was developed to estimate E. coli survival in gastric pH conditions as well as gene transfer from resistant to susceptible cells in humans. E. coli-contaminated retail foods for consumption without further cooking and gastric pH data in South Korea were considered as an example. The model predicts that 22-33% of commensal E. coli can survive under gastric pH conditions of Koreans. The estimated total mean tet(A) transfer level by commensal E. coli was 1.68 × 10-4-8.15 × 10-4log CFU/mL/h. The inactivation kinetic parameters of E. coli in SGF and the quantitative exposure model can provide useful information regarding risk management options to control the spread of AR.
authors.affiliation: Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-do 13539, South Korea; Department of Food Biotechnology, University of Science and Technology, Daejeon 34113, South Korea.
authors.forename: Daekeun
authors.initials: D
authors.lastname: Hwang
authors.affiliation: Department of Human Ecology, Korea National Open University, 86 Daehak-ro, Jongno-gu, Seoul 03087, South Korea.
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-do 13539, South Korea; Department of Food Biotechnology, University of Science and Technology, Daejeon 34113, South Korea. Electronic address: hjkim@kfri.re.kr.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D005516:Food Microbiology; D005750:Gastric Juice / Q000737:chemistry*; D022761:Gene Transfer, Horizontal; D006801:Humans; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability / Q000187:drug effects*; D008962:Models, Theoretical; D056910:Republic of Korea; D013753:Tetracycline Resistance
keywords: Escherichia coli; Gene transfer; Probabilistic exposure assessment; Simulated gastric fluid; Survival; Tetracycline resistance