title: Distribution of extended-spectrum beta-lactamase genes using a commercial DNA micro-array system.
abstract: Extended-spectrum beta-lactamase (ESBL) genes are distributed worldwide and their epidemiology is complex. Using the Check-ESBL assay, the distribution of class A ESBL genes in clinical isolates of aerobic Gram-negative bacilli from three laboratories in the East of The Netherlands was determined. Four patient categories were distinguished: (i) patients admitted to an intensive care unit (ICU); (ii) non-ICU inpatients; (iii) outpatients admitted less than a year before collection of the isolate, (<1); (iv) outpatients admitted more than one-year prior to isolate collection or who had never been hospitalized (>1). From February 2009 until March 2010, out of 491 putative ESBL-positive isolates detected by the Vitek2 or Phoenix automated sensitivity testing systems, ESBL genes were detected in 247 (50.3%) by the Check-ESBL assay. Of these, 116 were from hospitalized patients (35 ICU, 81 non-ICU) and 131 were from outpatients (43 <1, 88 >1). In all, 274 ESBL genes were identified in these 247 isolates: 153 CTX-M-1 group (predominantly in E. coli and K. pneumoniae, 70.4% and 51.6% respectively), 67 CTX-M-9 group (predominantly in E. cloacae, 57.9%), 32 SHV, 14 TEM and 8 CTX-M-2 group. ESBL-producing E. cloacae were significantly more common in hospitalized patients than in outpatients, 20.7% and 3.8% respectively (P=0.001). CTX-M-9 group ESBLs were significantly more prevalent in ICU patients (P=0.003), whereas SHV ESBLs were more common in hospitalized patients than in outpatients (P<0.001). There was no significant difference in distribution of ESBL genes between the two outpatient groups.
authors.affiliation: Department of Medical Microbiology and Medical Immunology, Rijnstate, Velp, The Netherlands. rnijhuis@rijnstate.nl
authors.forename: R H T
authors.initials: RH
authors.lastname: Nijhuis
authors.forename: A A
authors.initials: AA
authors.lastname: van Zwet
authors.forename: P H M
authors.initials: PH
authors.lastname: Savelkoul
authors.forename: E A
authors.initials: EA
authors.lastname: Roovers
authors.forename: R W
authors.initials: RW
authors.lastname: Bosboom
authors.forename: B
authors.initials: B
authors.lastname: Postma
authors.forename: A J
authors.initials: AJ
authors.lastname: van Griethuysen
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D005798:Genes, Bacterial; D006090:Gram-Negative Bacteria / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D009426:Netherlands / Q000453:epidemiology; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D015995:Prevalence; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases