title: Independent behavior of commensal flora for carriage of fluoroquinolone-resistant bacteria in patients at admission.
abstract: The important role of commensal flora as a natural reservoir of bacterial resistance is now well established. However, whether the behavior of each commensal flora is similar to that of other floras in terms of rates of carriage and risk factors for bacterial resistance is unknown. During a 6-month period, we prospectively investigated colonization with fluoroquinolone-resistant bacteria in the three main commensal floras from hospitalized patients at admission, targeting Escherichia coli in the fecal flora, coagulase-negative Staphylococcus (CNS) in the nasal flora, and α-hemolytic streptococci in the pharyngeal flora. Resistant strains were detected on quinolone-containing selective agar. Clinical and epidemiological data were collected. A total of 555 patients were included. Carriage rates of resistance were 8.0% in E. coli, 30.3% in CNS for ciprofloxacin, and 27.2% in streptococci for levofloxacin; 56% of the patients carried resistance in at least one flora but only 0.9% simultaneously in all floras, which is no more than random. Risk factors associated with the carriage of fluoroquinolone-resistant strains differed between fecal E. coli (i.e., colonization by multidrug-resistant bacteria) and nasal CNS (i.e., age, coming from a health care facility, and previous antibiotic treatment with a fluoroquinolone) while no risk factors were identified for pharyngeal streptococci. Despite high rates of colonization with fluoroquinolone-resistant bacteria, each commensal flora behaved independently since simultaneous carriage of resistance in the three distinct floras was uncommon, and risk factors differed. Consequences of environmental selective pressures vary in each commensal flora according to its local specificities (clinical trial NCT00520715 [http://clinicaltrials.gov/ct2/show/NCT00520715]).
authors.affiliation: Department of Internal Medicine, Hôpital Beaujon, Assistance-Publique Hôpitaux de Paris, 100 Boulevard Général Leclerc, 92100 Clichy, France.
authors.forename: Victoire
authors.initials: V
authors.lastname: de Lastours
authors.forename: Françoise
authors.initials: F
authors.lastname: Chau
authors.forename: Florence
authors.initials: F
authors.lastname: Tubach
authors.forename: Blandine
authors.initials: B
authors.lastname: Pasquet
authors.forename: Etienne
authors.initials: E
authors.lastname: Ruppé
authors.forename: Bruno
authors.initials: B
authors.lastname: Fantin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002939:Ciprofloxacin / Q000494:pharmacology; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects; D005243:Feces / Q000382:microbiology; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009296:Nasal Cavity / Q000382:microbiology; D015242:Ofloxacin / Q000494:pharmacology; D010614:Pharynx / Q000382:microbiology; D011446:Prospective Studies; D012307:Risk Factors; D013210:Staphylococcus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin