title: Risk factors for colonization and infection in a hospital outbreak caused by a strain of Klebsiella pneumoniae with reduced susceptibility to expanded-spectrum cephalosporins.
abstract: Between February 2001 and January 2002, an increase in the number of Klebsiella pneumoniae isolates with reduced susceptibility to expanded-spectrum cephalosporins (RSKp) was detected in the neonatal unit of the Juan Canalejo Hospital, and 21 patients were either colonized or infected by the bacterial isolates. The current "gold standard" method for typing K. pneumoniae isolates is pulsed-field gel electrophoresis. However, this technique is expensive and time-consuming. In a search for faster and accurate alternatives to this method, we investigated PCR-based fingerprinting techniques (enterobacterial repetitive intergenic consensus sequence PCR [ERIC-PCR], repetitive extragenic palindromic sequence-based PCR [REP-PCR], and RAPD [randomly amplified polymorphic DNA]) for their ability to characterize K. pneumoniae isolates. The causal agent of the nosocomial outbreak was characterized by these techniques and was found to be a single epidemic strain (RSKp). A multiple regression logistic model was developed to identify potential independent factors associated with colonization and/or infection by RSKp. Logistic regression analysis was applied to all significant variables (P < 0.05) in the univariate analysis, and it was revealed that intubation (odds ratio [OR], 27.0; 95% confidence interval [95%CI], 5.39 to 135.14) and prematurity (OR, 4.4; 95%CI, 0.89 to 21.89) were such independent factors. Moreover, oxime cephalosporins did not appear to be statistically significant. Overall, the results showed that PCR-based techniques are expeditious and useful methods for typing K. pneumoniae isolates. Of the techniques studied, ERIC-PCR showed the highest discriminatory index (D = 0.828), followed by RAPD (D = 0.826) and REP-PCR (D = 0.773)
authors.affiliation: Servicio de Microbiología, Complejo Hospitalario Juan Canalejo, C/As Xubias 84, 15006 La Coruña, Spain.
authors.forename: Monica
authors.initials: M
authors.lastname: Cartelle
authors.forename: Maria
authors.initials: M
authors.lastname: del Mar Tomas
authors.forename: Sonia
authors.initials: S
authors.lastname: Pertega
authors.forename: Alejandro
authors.initials: A
authors.lastname: Beceiro
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Dominguez
authors.forename: David
authors.initials: D
authors.lastname: Velasco
authors.forename: Francisca
authors.initials: F
authors.lastname: Molina
authors.forename: Rosa
authors.initials: R
authors.lastname: Villanueva
authors.forename: German
authors.initials: G
authors.lastname: Bou
mesh_terms: D002511:Cephalosporins / Q000494:pharmacology*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005243:Feces / Q000382:microbiology; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology
chemical_list: D002511:Cephalosporins