RESUMEN
OBJECTIVES: The aim of this study was to characterize carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates recovered from clinical specimens at a tertiary care hospital in Egypt over a period of 15 months. METHODS: Eight CRKP isolates were included in this study. The minimum inhibitory concentrations of different antibiotics were determined by broth microdilution and Etest methods. Multilocus sequence typing was performed. Antibiotic resistance genes were assessed by PCR and DNA sequencing. Plasmid analysis was done by S1 nuclease digestion of whole genomic DNA followed by pulsed-field gel electrophoresis (S1-PFGE). RESULT: Eight carbapenem-resistant NDM-1-producing K. pneumoniae isolates of three different sequence types (ST) were identified (ST147, ST11, and ST17), in which blaNDM-1 was carried by either IncR or untypeable plasmids. Seven out of the eight isolates also contained the rmtF methylase gene. CONCLUSION: This study describes the occurrence of IncR plasmids carrying blaNDM-1 and rmtF in Egypt, raising concerns regarding this type of replicon and its role in the transmission of these resistance determinants.
Asunto(s)
Antibacterianos/farmacología , Carbapenémicos/farmacología , Farmacorresistencia Microbiana/efectos de los fármacos , Infecciones por Enterobacteriaceae/tratamiento farmacológico , Infecciones por Klebsiella/tratamiento farmacológico , Klebsiella pneumoniae/efectos de los fármacos , beta-Lactamasas/metabolismo , Farmacorresistencia Microbiana/genética , Egipto/epidemiología , Electroforesis en Gel de Campo Pulsado , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/epidemiología , Infecciones por Enterobacteriaceae/microbiología , Humanos , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Tipificación de Secuencias Multilocus , Plásmidos , Análisis de Secuencia de ADN , beta-Lactamasas/efectos de los fármacos , beta-Lactamasas/genéticaRESUMEN
An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosa isolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding ß-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosa isolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and ß-lactamase production were responsible for the multidrug resistance in the isolates analysed.
Asunto(s)
Carbapenémicos/metabolismo , Farmacorresistencia Bacteriana Múltiple/genética , Mutación , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , Resistencia betalactámica/genética , beta-Lactamasas/metabolismo , Aminoglicósidos/metabolismo , Anfotericina B/análogos & derivados , Anfotericina B/metabolismo , Antifúngicos/metabolismo , Brasil , Cefalosporinasa/clasificación , Cefalosporinasa/metabolismo , Codón sin Sentido/metabolismo , Activación Enzimática/genética , Mutación del Sistema de Lectura/genética , Regulación Bacteriana de la Expresión Génica/genética , Humanos , Proteínas de Transporte de Membrana/metabolismo , Metiltransferasas/metabolismo , Nucleotidiltransferasas/metabolismo , Mutación Puntual/genética , Porinas/metabolismo , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/aislamiento & purificación , Secuencias Repetitivas de Ácidos Nucleicos , beta-Lactamasas/genéticaRESUMEN
An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosaisolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosaisolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.