title: Assessment of prevalence and changing epidemiology of extended-spectrum beta-lactamase-producing Enterobacteriaceae fecal carriers using a chromogenic medium.
abstract: Five hundred fecal samples from 462 patients (68.4% ambulatory) (February-April, 2007) from Madrid (Spain) were screened for extended-spectrum beta-lactamase (ESBL) producers using ceftazidime and cefotaxime (1 mg/L) MacConkey (MAC) agar plates and a chromogenic media (chromID ESBL; bioMérieux, Marcy-l'Etoile, France). bla(ESBL), qnr, aac(6')Ib-cr, and 16S rRNA methylase genes were assessed. A prevalence of 8.2% of ESBL fecal carriers was observed (8.9% hospitalized, 7.9% nonhospitalized patients), higher than that previously observed (1991, 0.6%; 2003, 7.0%). Sensitivity, specificity, and positive and negative predicted values were 100%, 94.8%, 63%, and 100% for chromID ESBL and 87.8%, 89.8%, 43.4%, and 98.9% for MAC, respectively. ESBL distribution was as follows: CTX-M-9-group, 40% (mainly CTX-M-14); CTX-M-1-group, 26.6% (mainly CTX-M-15); SHV-type, 29% (mainly SHV-12); and TEM-type, 4.4%. These enzymes were found in pulsed-field gel electrophoresis nonclonally related Escherichia coli and Klebsiella pneumoniae isolates. Transferable quinolone resistance was confirmed in CTX-M-9 (qnrS1), CTX-M-15 [aac(6')Ib-cr, qnrS1], and SHV-12 (qnrB7, qnrS1) producers but not 16S rRNA methylase genes. The chromID ESBL medium was reliable to screen ESBL fecal carriers with a general decrease in the laboratory workload. Time-to-time monitoring of ESBL fecal carriers is useful to ascertain current trend of ESBL epidemiology.
authors.affiliation: Servicio de Microbiología, Hospital Universitario Ramón y Cajal and CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Investigación Ramón y Cajal (IRYCIS), 28034-Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Paniagua
authors.forename: Aránzazu
authors.initials: A
authors.lastname: Valverde
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Coque
authors.forename: Fernando
authors.initials: F
authors.lastname: Baquero
authors.forename: Rafael
authors.initials: R
authors.lastname: Cantón
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001431:Bacteriological Techniques / Q000379:methods; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D003470:Culture Media / Q000737:chemistry; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D005243:Feces / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D015995:Prevalence; D015363:Quinolones / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology; D001618:beta-Lactamases / Q000096:biosynthesis*; D012359:tRNA Methyltransferases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003470:Culture Media; D015363:Quinolones; D012359:tRNA Methyltransferases; D001618:beta-Lactamases