title: Phenotypic and genotypic screening and clonal analysis of carbapenem-resistant Klebsiella pneumoniae at a single hospital.
abstract: Detection of bla(KPC)-harboring Klebsiella pneumoniae (KP) in the clinical laboratory remains a difficult task. Decreased ertapenem (ERT) susceptibility has been considered one of the most sensitive phenotypic indicators of K. pneumoniae carbapenemase (KPC) production, but has been found to be nonspecific. Susceptibility testing using imipenem or meropenem lacks the sensitivity for detection of KPCs, and there is limited experience using doripenem (DOR). Fifty-five individual ERT-nonsusceptible KP isolates and 19 isolates that were ERT-susceptible, extended spectrum β-lactamase-positive KP were collected from the clinical laboratory and tested for DOR susceptibility by Etest methodology. PCR screening for bla(KPC) was performed on all specimens. All but three isolates with ERT resistance were KPC positive by PCR. Compared to PCR, ERT detection of KPC had a sensitivity of 98% and a false-positive rate of 6%. Overall, there was a 97% agreement between ERT and DOR susceptibility results. However, there was one KPC-positive isolate that was discrepant (ERT susceptible, DOR nonsusceptible by Etest). Selected isolates of KP from both groups underwent pulsed-field gel electrophoresis analysis to determine the degree of genetic relatedness of KPC-positive and KPC-negative isolates. Pulsed-field gel electrophoresis of selected KPC-positive and KPC-negative KP identified a common pattern between both groups. The resistance to DOR and/or ERT is sensitive and a specific indicator for detection of bla(KPC) in KP.
authors.affiliation: University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Gomez
authors.forename: Carl
authors.initials: C
authors.lastname: Urban
authors.forename: Noriel
authors.initials: N
authors.lastname: Mariano
authors.forename: Rita
authors.initials: R
authors.lastname: Colon-Urban
authors.forename: Robert H K
authors.initials: RH
authors.lastname: Eng
authors.forename: David B
authors.initials: DB
authors.lastname: Huang
authors.forename: Tom
authors.initials: T
authors.lastname: Chiang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015373:Bacterial Typing Techniques; D015780:Carbapenems / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000235:genetics; D000077726:Doripenem; D016521:Electrophoresis, Gel, Pulsed-Field; D000077727:Ertapenem; D005838:Genotype; D006786:Hospitals, Urban; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D007710:Klebsiella Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013845:Thienamycins / Q000494:pharmacology; D014481:United States; D018440:beta-Lactam Resistance / Q000187:drug effects / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D004269:DNA, Bacterial; D013845:Thienamycins; D047090:beta-Lactams; D015378:Imipenem; D000077726:Doripenem; D001618:beta-Lactamases; C063912:carbapenemase; D000077731:Meropenem; D000077727:Ertapenem