Rémy Michel

Characteristics of human intestinal Escherichia coli with changing environments.

To investigate if the characteristics of human intestinal Escherichia coli are changing with the environment of the host, we studied intestinal E. coli from subjects having recently migrated from a temperate to a tropical area. We determined the phylogenetic group, the prevalence of the antibiotic resistance, the presence of integrons and the strain diversity in faecal isolates from 25 subjects originally from metropolitan France and expatriated to French Guyana. These characteristics were compared with those of 25 previously studied Wayampi Amerindian natives of French Guyana and from 25 metropolitan French residents. The three groups of subjects were matched for age and sex, had not taken antibiotics for at least 1 month, nor had been hospitalized within the past year. In all, the characteristics of intestinal E. coli from Expatriates were intermediate between those found in residents from metropolitan France and those found in natives of French Guyana. Prevalence of carriage of resistant Gram-negative bacteria in Expatriates was intermediate between French residents and Wayampi as were the prevalence of integrons in E. coli (12.3% versus 16.3% and 7.8% respectively), and the intra-host diversity of E. coli (2.3 strains/subject versus 1.9 and 3.1, respectively); lastly, in Expatriates, the prevalence of carriage of phylogenetic group B2 strains was lower than in French residents (16% versus 56%, P = 0.005), while carriage of phylogenetic group A strains was lower than in Wayampi (56% versus 88%, P = 0.03). Our results suggest that the composition of the commensal intestinal flora of humans is not static but changes dynamically in response to new environmental conditions.

Outbreak of typhoid fever in vaccinated members of the French Armed Forces in the Ivory Coast

In 2001, an outbreak of typhoid fever occurred among the members of the French Armed Forces. All had received a typhoid vaccination as per the immunization schedule practiced in the Armed Forces (every 5xa0years). A retrospective cohort study was conducted in 94 personnel. The objectives were to confirm the diagnosis, determine the source of contamination and identify the factors associated with defective vaccinal efficacy. Twenty-four cases were clinically identified. A cucumber salad was identified as the contaminating dish (Risk Ratio=3.6; 95%CI 1.5–8.9). Only one factor was related to defective vaccinal efficacy; the risk of typhoid fever was twofold higher in people vaccinated more than 3xa0years previously (Risk Ratio = 2.2; 95%CI, 1.1–4.2). Compliance with food hygiene rules could have prevented 24 cases of typhoid fever. Nevertheless, repeat vaccination against typhoid fever is now conducted every 3xa0years in the French Forces, in compliance with the manufacturers’ recommendations.

Chemoprophylaxis Compliance in a French Battalion After Returning From Malaria‐Endemic Area

Incidence of malaria is increasing in travelers and soldiers. In 2006, a survey was performed in a French battalion returning from a malaria-endemic area. According to the chemoprophylaxis plasma concentration and the individuals reports, the noncompliance rates were high, respectively, 63.4 and 54.7%.

The accuracy of self-reported data concerning recent cannabis use in the French armed forces.

BACKGROUNDnThe aims were to evaluate the accuracy of self-report of past-month cannabis use in a representative sample of French military staff members and to evaluate the scale of the prevarication bias.nnnMETHODnData from three cross-sectional surveys conducted between 2005 and 2008 (n = 3493) were used. The characteristics of self-report (sensitivity, specificity, positive predictive value and negative predictive value) were computed using tetrahydrocannabinol detection in urine as the reference.nnnRESULTSnThe prevalence for past-month cannabis use was 16.1% and for positive testing was 13.4%. The discriminant power of self-report was good, with an area under the receiver operating characteristics curve 0.90. Specificity (94.5%) and negative predictive values (97.8%) were good, but sensitivity (85.7%) and positive predictive values (70.4%) were lower. The lowest sensitivity values were observed in the higher categories of personnel and in the Navy, which could reflect some prevarication in these sub-populations who might believe they were more exposed to sanctions if detected.nnnCONCLUSIONSnDespite certain limitations of urine analysis as a reference, because of its poor detection of occasional users, our study is in favour of good accuracy of self-reported data on cannabis use, even among the military. However, our results, derived from a population study, do not enable any assumptions on the validity of self-reported data collected during individual testing procedures for the purpose of improving occupational safety.