title: [Emergence of colistin-resistant Klebsiella pneumoniae. Microbiological and epidemiological characterization of the isolates producing and non-producing KPC-type carbapenemase].
abstract: Sixty-four colistin-resistant Klebsiella pneumoniae isolates recovered from clinical specimens from 57 patients admitted to Hospital de Clinicas Jose de San Martin during the period 2010-2012 were studied to describe the microbiological and epidemiological characteristics and factors associated with the emergence of colistin-resistance. Fifty-four colistin-susceptible K. pneumoniae isolates from the same period were also included in the study. The genetic relatedness among the isolates was studied by a PCR assay. Fifty percent of the resistant isolates were KPC-2 producers, 45.3% were ESBL producers and 4.7% only showed resistance to aminopenicilins. All KPC-producers (resistant and susceptible to colistin) were genotipically indistinguishable except for one, whereas the presence of 7 clonal types, which were different from the ones identified in the colistin-susceptible isolates, were detected among ESBL producers. The previous use of colistin was the main factor associated with the acquisition of resistance, and in the case of non-KPC producers the stay in ICU was another significant factor observed. Colistin resistance emerged in our hospital in the year 2010, reaching 3% in nosocomial isolates and maintaining this rate in successive years, due to the selection of resistant subpopulations in the epidemic clonal type in KPC-producers and due to the dispersion of colistin-resistant clonal types in non-KPC producing-isolates.
authors.affiliation: Laboratorio de Bacteriología, Departamento de Bioquímica Clínica, Hospital de Clínicas José de San Martín, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Marcela
authors.initials: M
authors.lastname: Nastro
authors.forename: Néstor
authors.initials: N
authors.lastname: Carranza
authors.forename: Fernando
authors.initials: F
authors.lastname: Aprigliano
authors.forename: Elsa
authors.initials: E
authors.lastname: Saposnik
authors.forename: Claudia
authors.initials: C
authors.lastname: Barberis
authors.forename: Susana
authors.initials: S
authors.lastname: García
authors.forename: Carlos
authors.initials: C
authors.lastname: Vay
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Rodríguez
authors.forename: Angela
authors.initials: A
authors.lastname: Famiglietti
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000145:classification; D003091:Colistin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology*; D008297:Male; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000145:classification
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase; D003091:Colistin