title: Carbapenem resistance due to Bla(OXA-48) among ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates in a univesity hospital, Turkey.
abstract: Bacterial isolates producing Class D OXA-48 carbapenemase may be missed in routine laboratory testing, allowing them to spread undetected. The purpose of the present study was to detect bla(OXA-48) among ESBL-producing Klebsiella pneumoniae and Escherichia coli isolates collected from a university hospital, Turkey. Ninety-two ESBL-producing isolates (66 E. coli, 26 K. pneumoniae) were obtained in 2010. Antibiotic susceptibility tests were performed using the disc diffusion method and VITEK 2 system. Carbapenemase activity was screened using modified Hodge test. Beta-lactamase genes were detected by PCR and bla(OXA-48)-positive amplicons were sequenced. Genetic relatedness among K. pneumoniae isolates was investigated by pulsed-field gel-electrophoresis (PFGE). Carbapenemase activity was detected in 1 E. coli and 9 K. pneumoniae isolates and 8 of the K. pneumoniae plus the E. coli isolates were resistant to ertapenem. Three K. pneumoniae and 1 E. coli isolates were resistant to imipenem. All 10 isolates were susceptible to meropenem. bla(OXA-48) was present in all 10 isolates. Additionally, 9 isolates contained at least one beta-lactamase gene, including bla(SHV') bla(CTX-M) and bla(VEB) type. PFGE revealed different karyotypes among 9 K. pneumoniae isolates suggesting that the dissemination of bla(OXA-48) gene was not spread by a single K. pneumoniae clone. Thus OXA-48-producing isolates found in carbapenem-susceptible strains according to CLSI guidelines.
authors: Department of Microbiology and Clinical Microbiology, Istanbul Medical Faculty, Istanbul Universiy, Istanbul, Turkey. hasannazik01@gmail.com
authors: Hasan
authors: H
authors: Nazik
authors: Betigul
authors: B
authors: Ongen
authors: Mehmet
authors: M
authors: Ilktac
authors: Selda
authors: S
authors: Aydin
authors: Nuray
authors: N
authors: Kuvat
authors: Aysegul
authors: A
authors: Sahin
authors: Mucahit
authors: M
authors: Yemisen
authors: Bilgul
authors: B
authors: Mete
authors: Mehmet Sait
authors: MS
authors: Durmus
authors: Ilker Inanc
authors: II
authors: Balkan
authors: Ismail
authors: I
authors: Yildiz
authors: Yakup
authors: Y
authors: Ergul
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D015780:Carbapenems / Q000494:pharmacology*; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D006785:Hospitals, University; D006801:Humans; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D014421:Turkey / Q000453:epidemiology; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D015780:Carbapenems; D001618:beta-Lactamases; C063912:carbapenemase; C108449:oxacillinase