title: Comparison of Molecular and Phenotypic Methods for the Detection and Characterization of Carbapenem Resistant Enterobacteriaceae.
abstract: In recent years, there has been a rapid dissemination of carbapenem resistant Enterobacteriaceae (CRE). This study aimed to compare phenotypic and molecular methods for detection and characterization of CRE isolates at a large tertiary care hospital in Saudi Arabia. This study was carried out between January 2011 and November 2013 at the King Khalid University Hospital (KKUH) in Saudi Arabia. Determination of presence of extended-spectrum beta-lactamases (ESBL) and carbapenem resistance was in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Phenotypic classification was done by the MASTDISCS(TM) ID inhibitor combination disk method. Genotypic characterization of ESBL and carbapenemase genes was performed by the Check-MDR CT102. Diversilab rep-PCR was used for the determination of clonal relationship. Of the 883 ESBL-positive Enterobacteriaceae detected during the study period, 14 (1.6%) isolates were carbapenem resistant. Both the molecular genotypic characterization and phenotypic testing were in agreement in the detection of all 8 metalo-beta-lactamases (MBL) producing isolates. Of these 8 MBL-producers, 5 were positive for blaNDM gene and 3 were positive for blaVIM gene. Molecular method identified additional blaOXA gene isolates while MASTDISCS(TM) ID detected one AmpC producer isolate. Both methods agreed in identifying 2 carbapenem resistant isolates which were negative for carbapenemase genes. Diversilab rep-PCR analysis of the 9 Klebsiella pneumoniae isolates revealed polyclonal distribution into eight clusters. MASTDISCS(TM) ID is a reliable simple cheap phenotypic method for detection of majority of carbapenemase genes with the exception of the blaOXA gene. We recommend to use such method in the clinical laboratory.
authors.affiliation: Department of Pathology and Laboratory Medicine, Microbiology Unit, College of Medicine, King Saud University and King Saud University Medical City , Riyadh , Saudi Arabia.
authors.forename: Ali M
authors.initials: AM
authors.lastname: Somily
authors.affiliation: Department of Microbiology & Immunology, College of Medicine, Alfaisal University , Riyadh , Saudi Arabia.
authors.forename: Ghada A
authors.initials: GA
authors.lastname: Garaween
authors.affiliation: Department of Pathology and Laboratory Medicine, Microbiology Unit, College of Medicine, King Saud University and King Saud University Medical City , Riyadh , Saudi Arabia.
authors.forename: Norah
authors.initials: N
authors.lastname: Abukhalid
authors.affiliation: Department of Pathology and Laboratory Medicine, Microbiology Unit, College of Medicine, King Saud University and King Saud University Medical City , Riyadh , Saudi Arabia.
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Absar
authors.affiliation: Department of Microbiology & Immunology, College of Medicine, Alfaisal University , Riyadh , Saudi Arabia.|Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre , Riyadh , Saudi Arabia.
authors.forename: Abiola C
authors.initials: AC
authors.lastname: Senok
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010641:Phenotype; D012529:Saudi Arabia; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Check-MDR; DNA microarray; Enterobacteriaceae; MASTDISCSTM ID; Modified Hodge Test; blaNDM gene; blaOXA gene; blaVIM gene; carbapenem resistance; molecular characterization