ABSTRACT
A multicenter survey, carried out in 2010 in Argentina, showed an increased prevalence of extended-spectrum ß-lactamase (ESBL)-producing enterobacteria, with some changes in the molecular epidemiology of circulating ESBLs. While enzymes of the CTX-M-2 group remain endemic, the emergence of CTX-M-15 and of enzymes of the CTX-M-8 and CTX-M-9 groups was observed. The CTX-M-15-positive isolates represented 40% of CTX-M producers and included representatives of Escherichia coli ST131 and Klebsiella pneumoniae ST11.
Subject(s)
Escherichia coli Infections/drug therapy , Escherichia coli/drug effects , Klebsiella Infections/drug therapy , Klebsiella pneumoniae/drug effects , beta-Lactam Resistance/genetics , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Argentina/epidemiology , Escherichia coli/genetics , Escherichia coli Infections/epidemiology , Escherichia coli Infections/microbiology , Genetic Heterogeneity , Humans , Klebsiella Infections/epidemiology , Klebsiella Infections/microbiology , Klebsiella pneumoniae/genetics , beta-Lactam Resistance/drug effects , beta-Lactamases/metabolism , beta-Lactams/pharmacology , beta-Lactams/therapeutic useABSTRACT
En el presente estudio, que tuvo por objeto analizar los mecanismos involucrados en la resistencia a carbapenemes, se incluyeron 129 aislamientos de Pseudomonas aeruginosa recuperados durante el año 2006 en el Hospital "Eva Perón" de la Provincia de Buenos Aires. La caracterización fenotípica y genotípica de la resistencia permitió reconocer la presencia de metalo-beta-lactamasas (MBL) en el 14% de esos aislamientos. En todos ellos se identificó la presencia de la enzima IMP-13; sin embargo, algunos aislamientos resultaron sensibles a carbapenemes de acuerdo con los puntos de corte establecidos por el CLSI e incluso con las sugerencias de la Subcomisión de Antimicrobianos de SADEBAC, AAM. El ensayo de detección fenotípica de MBL de sinergia con doble disco resultó útil en este estudio. Sólo aquellos aislamientos productores de IMP-13 que a su vez presentaron alteraciones en las proteínas de membrana externa resultaron completamente resistentes a imipenem. Los aislamientos productores de MBL correspondieron a varios tipos clonales, lo cual sugiere no sólo la diseminación de una cepa resistente, sino también la diseminación horizontal de este mecanismo de resistencia entre clones diferentes.
From 129 P. aeruginosa isolated at a health care centre located in Buenos Aires (Hospital "Eva Perón"), 14% produced IMP-13. Although 18 isolates were metallo-beta-lactamases (MBL) producers, only those isolates that displayed altered outer membrane protein profiles correlated with the resistant category according to CLSI or even Subcomisión de Antimicrobianos, SADEBAC, AAM. Phenotypic screening of metallo-beta-lactamases proved to be appropriate for detecting MBL producing isolates. IMP-13 producing isolates corresponded to at least five different clonal types, which not only suggests the dissemination of the resistant strain but also of the resistant marker.
Subject(s)
beta-Lactam Resistance , Cross Infection/microbiology , Drug Resistance, Multiple, Bacterial , Imipenem/pharmacology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/isolation & purification , Argentina/epidemiology , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/analysis , Bacterial Proteins/genetics , Ceftazidime/pharmacology , Cross Infection/epidemiology , Genotype , Microbial Sensitivity Tests , Phenotype , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/genetics , Sequence Analysis, DNA , beta-Lactamases/analysis , beta-Lactamases/geneticsABSTRACT
From 129 P. aeruginosa isolated at a health care centre located in Buenos Aires (Hospital "Eva Perón"), 14% produced IMP-13. Although 18 isolates were metallo-beta-lactamases (MBL) producers, only those isolates that displayed altered outer membrane protein profiles correlated with the resistant category according to CLSI or even Subcomisión de Antimicrobianos, SADEBAC, AAM. Phenotypic screening of metallo-beta-lactamases proved to be appropriate for detecting MBL producing isolates. IMP-13 producing isolates corresponded to at least five different clonal types, which not only suggests the dissemination of the resistant strain but also of the resistant marker.
