title: Evaluation of a new chromogenic medium, chromID OXA-48, for recovery of carbapenemase-producing Enterobacteriaceae from patients at a university hospital in Turkey.
abstract: The purpose of this study was to evaluate a new chromogenic medium, chromID OXA-48, for the isolation of carbapenemase-producing Enterobacteriaceae (CPE) directly from rectal swabs. chromID CARBA and chromID OXA-48 are two chromogenic media that have been commercialized for the isolation of CPE directly from clinical samples. Both media were evaluated alongside a broth enrichment method recommended by the CDC for isolation of CPE, with rectal swabs from 302 unique hospitalized patients at the Hacettepe University Hospital, Ankara, Turkey. A total of 33 patients (11 %) were found to be colonized with CPE using a combination of all methods, and all CPE produced OXA-48 carbapenemase. Klebsiella pneumoniae was by far the most dominant species of CPE and was isolated from 31 patients. Culture on chromID OXA-48 offered the highest sensitivity (75.8 %) for detection of CPE compared with the other two methods (sensitivity for both other methods was 57.6 %) and also offered the highest specificity (99.3 %). However, a combination of methods (either chromID OXA-48 plus CDC method or chromID OXA-48 plus chromID CARBA) was necessary to achieve an acceptable sensitivity (90.9 %). For isolation of CPE, in a setting where OXA-48 carbapenemase is the dominant type of carbapenemase, chromID OXA-48 is a highly useful medium but using a combination of methods is optimal for adequate detection. The combined use of two chromogenic media offered acceptable sensitivity (90.9 %) and the highest specificity (98.5 %) and also allowed for isolation of CPE within 18-20 h.
authors.affiliation: Department of Infectious Diseases and Clinical Microbiology, Hacettepe University School of Medicine, Ankara, 06100, Turkey.
authors.forename: P
authors.initials: P
authors.lastname: Zarakolu
authors.forename: K M
authors.initials: KM
authors.lastname: Day
authors.forename: H E
authors.initials: HE
authors.lastname: Sidjabat
authors.forename: W
authors.initials: W
authors.lastname: Kamolvit
authors.forename: C V
authors.initials: CV
authors.lastname: Lanyon
authors.forename: S P
authors.initials: SP
authors.lastname: Cummings
authors.forename: D L
authors.initials: DL
authors.lastname: Paterson
authors.forename: M
authors.initials: M
authors.lastname: Akova
authors.forename: J D
authors.initials: JD
authors.lastname: Perry
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D001431:Bacteriological Techniques / Q000379:methods*; D002863:Chromogenic Compounds / Q000378:metabolism; D003116:Color; D003470:Culture Media / Q000737:chemistry*; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D006785:Hospitals, University; D006801:Humans; D012007:Rectum / Q000382:microbiology; D012680:Sensitivity and Specificity; D014421:Turkey; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D001426:Bacterial Proteins; D002863:Chromogenic Compounds; D003470:Culture Media; D001618:beta-Lactamases; C063912:carbapenemase