Open AccessInflux of Enterococci and Associated Antibiotic Resistance and Virulence Genes from Ready-To-Eat Food to the Human Digestive Tract
Author(s) -
Lilia Macovei,
Ludek Zurek
Publication year - 2007
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.01444-07
Subject(s) - tetracycline , enterococcus hirae , biology , microbiology and biotechnology , virulence , enterococcus , enterococcus faecium , enterococcus faecalis , kanamycin , erythromycin , pulsed field gel electrophoresis , antibiotic resistance , gene , antibiotics , genotype , genetics , escherichia coli
The influx of enterococcal antibiotic resistance (AR) and virulence genes from ready-to-eat food (RTEF) to the human digestive tract was assessed. Three RTEFs (chicken salad, chicken burger, and carrot cake) were sampled from five fast-food restaurants five times in summer (SU) and winter (WI). The prevalence of enterococci was significantly higher in SU (92.0% of salad samples and 64.0% of burger samples) than in WI (64.0% of salad samples and 24.0% of burger samples). The overall concentrations of enterococci during the two seasons were similar (∼103 CFU/g); the most prevalent wereEnterococcus casseliflavus (41.5% of isolates) andEnterococcus hirae (41.5%) in WI andEnterococcus faecium (36.8%),E. casseliflavus (27.6%), andEnterococcus faecalis (22.4%) in SU. Resistance in WI was detected primarily to tetracycline (50.8%), ciprofloxacin (13.8%), and erythromycin (4.6%). SU isolates were resistant mainly to tetracycline (22.8%), erythromycin (22.1%), and kanamycin (13.0%). The most commontet gene wastet (M) (35.4% of WI isolates and 11.9% of SU isolates). The prevalence of virulence genes (gelE ,asa1 ,cylA , andesp ) and marker genes for clinical isolates (EF_0573, EF_0592, EF_0605, EF_1420, EF_2144, and pathogenicity island EF_0050) was low (≤12.3%). Genotyping ofE. faecalis andE. faecium using pulsed-field gel electrophoresis revealed that the food contamination likely originated from various sources and that it was not clonal. Our conservative estimate (single AR gene copy per cell) for the influx oftet genes alone to the human digestive tract is 3.8 × 105 per meal (chicken salad). This AR gene influx is frequent because RTEFs are commonly consumed and that may play a role in the acquisition of AR determinants in the human digestive tract.