title: Rapid detection of amoxicillin-susceptible Escherichia coli in fresh uncultured urine: a new tool to limit the use of broad-spectrum empirical therapy of community-acquired pyelonephritis.
abstract: Because of the high prevalence of amoxicillin resistance among uropathogens, amoxicillin is not recommended as an empirical treatment of urinary tract infections (UTIs). Quick detection of an amoxicillin-susceptible Escherichia coli (ASEC) would allow prescribing amoxicillin without preliminary broad-spectrum empirical treatment in uncomplicated pyelonephritis. To quickly diagnose UTIs due to ASEC, we developed a real-time PCR that detects in fresh uncultured urine the E. coli-specific gene yccT as well as the blaTEM and blaCTX-M genes. The ASEC rapid test was considered positive if the PCR was positive for the yccT gene but negative for blaTEM and blaCTX-M. The test was compared with culture and susceptibility testing. Among 200 patients with a suspected community-acquired UTI, 61 (30.5%) had a monobacterial UTI due to ASEC. The ASEC rapid test result was obtained in 3 h 13 [95% confidence interval (CI) 3 h 12-3 h 15] and was positive for 43 patients (21.5%). Specificity and sensitivity were 97.8% (95% CI 95.8-99.8%) and 65.6% (95% CI 59.0-72.1%), respectively. Positive and negative predictive values were 93.0% (95% CI 89.5-96.5%) and 86.6% (95% CI 81.9-91.3%), respectively. Owing to its high specificity and positive predictive value, the ASEC rapid test allows the diagnosis of UTI due to ASEC only 3 h after urine sampling. A positive ASEC rapid test may be used to treat uncomplicated pyelonephritis with amoxicillin from the start, without preliminary broad-spectrum empirical treatment. The ASEC rapid test is a promising tool to spare fluoroquinolones and third-generation cephalosporins in UTIs.
authors.affiliation: EA3826 Thérapeutiques cliniques et expérimentales des infections, Faculté de Médecine, Université de Nantes, 1 rue Gaston-Veil, F-44000 Nantes, France; Clinical Gerontology Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France. Electronic address: guillaume.chapelet@chu-nantes.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Chapelet
authors.affiliation: EA3826 Thérapeutiques cliniques et expérimentales des infections, Faculté de Médecine, Université de Nantes, 1 rue Gaston-Veil, F-44000 Nantes, France; Bacteriology Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Corvec
authors.affiliation: EA3826 Thérapeutiques cliniques et expérimentales des infections, Faculté de Médecine, Université de Nantes, 1 rue Gaston-Veil, F-44000 Nantes, France; Emergency Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Montassier
authors.affiliation: Bacteriology Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Herbreteau
authors.affiliation: Clinical Gerontology Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Berrut
authors.affiliation: EA3826 Thérapeutiques cliniques et expérimentales des infections, Faculté de Médecine, Université de Nantes, 1 rue Gaston-Veil, F-44000 Nantes, France; Emergency Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Batard
authors.affiliation: EA3826 Thérapeutiques cliniques et expérimentales des infections, Faculté de Médecine, Université de Nantes, 1 rue Gaston-Veil, F-44000 Nantes, France; Clinical Gerontology Department, Centre Hospitalier Universitaire de Nantes, 1 place Alexis-Ricordeau, F-44000 Nantes, France.
authors.forename: Laure
authors.initials: L
authors.lastname: de Decker
mesh_terms: D000328:Adult; D000368:Aged; D000658:Amoxicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017714:Community-Acquired Infections / Q000175:diagnosis* / Q000188:drug therapy; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011704:Pyelonephritis / Q000175:diagnosis* / Q000188:drug therapy; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000658:Amoxicillin
keywords: Antibacterial agents; Escherichia coli; Real-time PCR; Urinary tract infection; β-Lactamase