Use of molecular typing to investigate bacterial translocation from the intestinal tract of chlorpyrifos-exposed rats.
BACKGROUND
Human are confronted on a daily basis with contaminant pesticide residues in food, water and other components of the environment. Although the digestive system is the first organ to come into contact with food contaminants, very few data are available on the impact of low-dose pesticide exposure during the in utero and postnatal periods on intestinal bacterial translocation (BT). Previous studies have revealed that chlorpyrifos (CPF) exposure is associated with intestinal dysbiosis and the contamination of sterile organs. Here, molecular typing was used to investigate intestinal bacterial translocation in rats exposed to chlorpyrifos in utero and during lactation. The translocated bacteria were profiled, and CPF tolerance and antibiotic resistance traits were determined.


METHODS
A total of 72 intestinal segments and extra-intestinal organs were obtained from 14 CPF-exposed rats. The samples were cultured to isolate bacterial strains that had tolerated treatment with 1 or 5 mg CPF/kg bodyweight/day in vivo. Strains were identified using matrix-assisted laser desorption/ionization (MALDI) Biotyper. The disk diffusion method was used to determine the antibiotic susceptibility. The isolates were genotyped with PCR assays for the enterobacterial repetitive intergenic consensus sequence and random amplification polymorphic DNA.


RESULTS
Bacterial translocation was confirmed for 7 of the 31 strains (22.6 %) isolated from extra-intestinal sites. Overall, the most prevalent bacteria wereStaphylococcus aureus (55.5 % of the 72 intestinal and extra-intestinal isolates),Enterococcus faecalis(27.7 %) andBacillus cereus(9.8 %). 5 % of theS. aureusisolates displayed methicillin resistance. Seventy two strains were identified phenotypically, and seven translocated strains (mainlyS. aureus) were identified by genotyping. Genotypically confirmed translocation was mainly observed found in pesticide-exposed groups (6 out of 7).


CONCLUSIONS
BT from the intestinal tract colonized normally sterile extra-intestinal organs in CPF-exposed rats. Our findings validate the use of molecular typing for the assessment of intestinal BT in CPF-exposed rats during critical periods of development.
Laboratoire PeriTox UMR I 01, Faculty of Medicine, Centre Universitaire de Recherche Scientifique, Université de Picardie Jules Verne, Avenue René Laёnnec, 80054 Amiens cedex 1, France ; Laboratoire LNPC EA4666, Faculty of Medicine, Centre Universitaire de Recherche Scientifique, Université de Picardie Jules Verne, Avenue René Laёnnec, 80054 Amiens cedex 1, France.
Claire
C
Joly Condette
Laboratoire PeriTox UMR I 01, Faculty of Medicine, Centre Universitaire de Recherche Scientifique, Université de Picardie Jules Verne, Avenue René Laёnnec, 80054 Amiens cedex 1, France.
Bertin
B
Elion Dzon
Laboratoire de Bactériologie, Centre Hospitalier Universitaire Amiens Picardie, Avenue René Laёnnec, Salouёl, 80054 Amiens cedex 1, France.
Farida
F
Hamdad
Laboratoire PeriTox UMR I 01, Faculty of Medicine, Centre Universitaire de Recherche Scientifique, Université de Picardie Jules Verne, Avenue René Laёnnec, 80054 Amiens cedex 1, France ; Laboratoire de Bactériologie, Centre Hospitalier Universitaire Amiens Picardie, Avenue René Laёnnec, Salouёl, 80054 Amiens cedex 1, France.
Maurice
M
Biendo
Laboratoire PeriTox UMR I 01, Faculty of Medicine, Centre Universitaire de Recherche Scientifique, Université de Picardie Jules Verne, Avenue René Laёnnec, 80054 Amiens cedex 1, France.
Véronique
V
Bach
Laboratoire PeriTox UMR I 01, Faculty of Medicine, Centre Universitaire de Recherche Scientifique, Université de Picardie Jules Verne, Avenue René Laёnnec, 80054 Amiens cedex 1, France.
Hafida
H
Khorsi-Cauet
Bacterial translocation; Chlorpyrifos; In utero; Intestinal permeability; Lactational period; Molecular typing; Rat