Perigestational exposure of a combination of a high-fat diet and pesticide impacts the metabolic and microbiotic status of dams and pups; a preventive strategy based on prebiotics.

PURPOSE: Metabolic changes during the perinatal period are known to promote obesity and type-2 diabetes in adulthood via perturbation of the microbiota. The risk factors for metabolic disorders include a high-fat diet (HFD) and exposure to pesticide residues. The objective of the present study was to evaluate the effects of perigestational exposure to a HFD and chlorpyrifos (CPF) on glycemia, lipid profiles, and microbial populations in Wistar dams and their female offspring. We also tested a preventive strategy based on treatment with the prebiotic inulin. METHODS: From 4 months before gestation to the end of the lactation period, six groups of dams were exposed to either a standard diet, a HFD alone, CPF alone, a combination of a HFD and CPF, and/or inulin supplementation. All female offspring were fed a standard diet from weaning to adulthood. We measured the impacts of these exposures on glycemia, the lipid profile, and the microbiota (composition, metabolite production, and translocation into tissues). RESULTS: HFD exposure and CPF + HFD co-exposure induced dysmetabolism and an imbalance in the gut flora in both the dams and the female offspring. Inulin mitigated the impact of exposure to a HFD alone but not that of CPF + HFD co-exposure. CONCLUSION: Our results provide a better understanding of the complex interactions between environmental pollutants and diet in early life, including in the context of metabolic diseases.

Comparison of Xpert MRSA/SA Nasal and MRSA/SA ELITe MGB assays for detection of the mecA gene with susceptibility testing methods for determination of methicillin resistance in Staphylococcus aureus isolates.

In a series of 82 Staphylococcus strains isolated from culture, 100% were identified as Staphylococcus aureus by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS); 99.9% (77/82) of them were resistant to benzylpenicillin, oxacillin, and cefoxitin, and 6.1% (5/82) were susceptible to methicillin. Xpert MRSA/SA assay results were concordant with the phenotypic results in 76.8% (63/82) of cases and discordant in 23.2% (19/82) of cases. The MRSA/SA ELITe MGB kit results were concordant with phenotypic results in 100% of the cases. When comparing the Xpert MRSA/SA assay results with the MRSA/SA ELITe MGB kit results, 78% (64/82) of the cases were concordant, while 22% (18/82) of the cases were discordant. No statistically significant differences were observed between the two techniques. The PCR protocol that was used to validate the results of these two methods gave the following results: 49 were conventional methicillin-resistant S. aureus (MRSA) isolates (mecA positive and mecALGA251 negative), and 25 were phenotypic MRSA isolates (mecA negative and mecALGA251 positive).

Molecular typing and characterization of extended-spectrum TEM, SHV and CTX-M beta-lactamases in clinical isolates of Enterobacter cloacae.

Sixty-one non-repetitive Enterobacter cloacae ESBL producers were collected at the Amiens University Hospital in France. Eight beta-lactam resistance phenotypes (a-h) and three aminoglycoside resistance phenotypes (i-k) were identified among these isolates, and 32 different pulsotypes were observed. Of these 61 isolates, 37 were sequenced and found to harbor beta-lactamases with a pI of 5.9 (TEM-4), 6.5 (TEM-24), 7.8 (SHV-4), 8.2 (SHV-12), 8.4 (CTX-M-1) and 8.0 (CTX-M-9). Four imipenem-resistant ESBL-producing E. cloacae isolates did not express the 38kDa OMP, indicating that this resistance is associated with porin deficiency.

community-acquired infection with healthcare-associated methicillin-resistant Staphylococcus aureus: the role of home nursing care.

OBJECTIVE: To better understand the role of indirect transmission in community-acquired infection with methicillin-resistant Staphylococcus aureus (MRSA). DESIGN: Prospective case-control study. SETTING: A French teaching hospital. PATIENTS: A total of 198 case patients and 198 control patients with MRSA or methicillin-susceptible S. aureus infection diagnosed between April 2002 and July 2003. RESULTS: Multivariate analysis showed a highly significant independent link between MRSA infection at admission and prior receipt of home nursing care (odds ratio [OR], 3.7; P<.001). Other independent risk factors were prior hospitalization (OR, 3.8; P<.001), transfer from another institution (OR, 2.3; P=.008), and age older than 65 years (OR, 1.6; P=.04). Prior home nursing care showed a frequency dose-response relationship. Eleven MRSA-infected patients had had home nursing procedures but no hospital stay in the previous 3 years. These patients' MRSA strains were related to the prevalent MRSA clone currently spreading in French hospitals. CONCLUSION: Home nursing care appears to be an independent risk factor for MRSA acquisition in the community. The reservoir probably consists of MRSA carriers discharged from the hospital. Community nurses seem to be a potential vector.

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 were Staphylococcus aureus (55.5 % of the 72 intestinal and extra-intestinal isolates), Enterococcus faecalis (27.7 %) and Bacillus cereus (9.8 %). 5 % of the S. aureus isolates displayed methicillin resistance. Seventy two strains were identified phenotypically, and seven translocated strains (mainly S. aureus) were identified by genotyping. Genotypically confirmed translocation was mainly observed found in pesticide-exposed groups (6 out of 7). CONCLUSION: 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.

Molecular characterisation and mechanisms of resistance of multidrug-resistant human Salmonella enterica serovar Typhimurium isolated in Amiens (France).

Antimicrobial resistance patterns of Salmonella enterica serovar Typhimurium isolates obtained during the study period were examined. The molecular epidemiology and the mechanisms of resistance to ampicillin, chloramphenicol and tetracycline were investigated. Resistance to ampicillin increased from 59% between 1996 and 1999 to 62.5% in 2000 and to 66.6% in 2001. Of 51 S. Typhimurium isolates studied, 100% were resistant to ampicillin (minimum inhibitory concentration (MIC)>256 mg/L) and sulphonamide (MIC range, 128 to >256 mg/L). Ninety-eight percent of isolates were resistant to streptomycin (MIC range, 48-256 mg/L), 92.2% to tetracycline (MIC range, 32 to >256 mg/L), 88.2% to chloramphenicol (MIC>256 mg/L), 21.5% to sulphamethoxazole/trimethoprim (MIC>32 mg/L), 5.8% to amoxicillin/clavulanic acid (MIC, 32 mg/L) and 1.9% to cefalothin (MIC, 64mg/L). Six resistance phenotypes were found (a-f), with phenotypes a (47%) and b (27.5%) being predominant. Twenty-five (49%) of 51 isolates produced a single beta-lactamase, among which 48% produced PSE-1, 44% produced TEM-1 and 8% produced OXA-1. Among 26 of the 51 isolates, 10 produced PSE-1+OXA-1, 7 produced TEM-1+PSE-1+OXA-1, 6 produced TEM-1+PSE-1, and 3 produced TEM-1+OXA-1. Forty-eight (94.1%) of the 51 isolates had the plasmid-mediated resistance gene flo(ST) to chloramphenicol and tetracycline. Combining enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) and pulsed-field gel electrophoresis (PFGE), 16 distinct patterns were identified, among which patterns IA (35.3%) and IF (27.4%) were considered as epidemic patterns. The dendrogram obtained from S. Typhimurium pulsotypes allowed five clones (S1-S5) to be identified, with two prevalent clones comprising 47.8% (S2) and 27.3% (S4) of the isolates.

Value of Xpert MRSA/SA blood culture assay on the Gene Xpert® Dx System for rapid detection of Staphylococcus aureus and coagulase-negative staphylococci in patients with staphylococcal bacteremia.

The Xpert MRSA/SA BC assay was examined prospectively in patients with staphylococcal bacteremia including 6 patients with blood culture bottles inoculated with biological fluid (synovial fluid in 4 cases and peritoneal fluid in 2 cases). Among the 56 Staphylococci species isolated, 80.3% were coagulase-negative staphylococci (CoNS) and 19.7% were S. aureus. Methicillin susceptibility test results showed that 77.8% of isolates were methicillin-resistant CoNS (MRCoNS) and 22.2% of isolates were methicillin-susceptible CoNS (MSCoNS). Of 11 S. aureus isolates, 63.7% were methicillin-susceptible S. aureus (MSSA) and 36.3% were methicillin-resistant S. aureus (MRSA). Xpert MRSA/SA BC results showed that genotypic results were in concordance with phenotypic results in 94.6% of cases versus 5.4% of discordant cases. Of these 3 discordant cases, 1 S. aureus isolate had an MRSA phenotype and an SPA(+)mec(+)SCCmec(-) genotype and another S. aureus isolate was phenotypically MSSA and genotypically SPA(+)mec(+)SCCmec(-), and 1 S. epidermidis isolate was phenotypically MSCoNS and genotypically SPA(-)mec(+)SCCmec(-).

Molecular epidemiology of ampicillin-resistant clinical isolates of Salmonella enterica serovar Typhimurium.

Thirty-nine multiresistant Salmonella enterica serovar Typhimurium (S. Typhimurium) isolates were obtained from 33 children and 6 adults hospitalized from 1996 to 1999 in the University Hospital of Amiens (France). S. Typhimurium was cultured from stools (n=36), blood samples (n=2) and peritoneal fluid (n=1). These isolates were characterized by biotyping, antibiotic susceptibility test, RAPD-PCR, and PFGE typing. Emergence of pentaresistant S. Typhimurium isolates (phenotype ACSSuTe) was observed, and five of them were resistant to nalidixic acid and of intermediate susceptibility to pefloxacin. Genotypic analysis of both RAPD and PFGE results showed that there were 7 different patterns. Thirty-three isolates gave an identical pattern (AI) and were considered as epidemic isolates; the six remaining patterns (each containing one isolate) corresponded to sporadic cases. Antibiotic susceptibility patterns, RAPD and PFGE patterns subdivided the 39 isolates into 9 clonally related groups. One of them (pattern AI and R-pattern a) was implicated in 74% of the cases.