RESUMO
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.
Assuntos
Proteínas de Bactérias/biossíntese , Colistina/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , beta-Lactamases/biossíntese , Proteínas de Bactérias/classificação , Farmacorresistência Bacteriana , Feminino , Humanos , Infecções por Klebsiella/epidemiologia , Masculino , beta-Lactamases/classificaçãoRESUMO
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.
Assuntos
Colistina/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Proteínas de Bactérias/biossíntese , beta-Lactamases/biossíntese , Farmacorresistência Bacteriana , Feminino , Humanos , Infecções por Klebsiella/epidemiologia , Masculino , Proteínas de Bactérias/classificação , beta-Lactamases/classificaçãoRESUMO
Entre los años 1996 y 2010 se estudiaron 1873 aislamientos de Enterococcus spp. pertenecientes a pacientes internados en un hospital universitario de la Ciudad Autónoma de Buenos Aires con infección intrahospitalaria. El 64,2% y el 30,4% de los aislamientos correspondieron a E. faecalis y E. faecium, respectivamente. En el periodo estudiado las infecciones por Enterococcus spp. representaron entre el 8% y el 10% del total de las infecciones nosocomiales. La prevalencia de E. faecium aumentó de un 1,5% en el año 1996 a un 4% en 2010. El primer aislamiento de enterococo resistente a vancomicina se detectó en el año 1998 y correspondió a un E. faecium y en el año 2004 se halló en E. faecalis. Actualmente más del 70% de los aislamientos de E. faecium son resistentes a vancomicina, no así en E. faecalis donde la resistencia es ocasional. No se detectó resistencia a linezolid ni a tigeciclina en Enterococcus spp.(AU)
One thousand eight hundred and seventy-three Enterococcus spp. isolates belonging to patients undergoing hospital-acquired infections at the University Hospital of Buenos Aires city were studied between the years 1996 and 2010. A total of 64.2% and 30.4% of the isolates were identified as E. faecalis y E. faecium respectively. The infections caused by Enterococcus spp. represented from 8% to 10% of the total number of the nosocomial infections in the period studied. The E. faecium prevalence increased from 1.5% in 1996 to 4% in 2010. The first vancomycin-resistant Enterococcus faecium was detected in the year 1998 and in the year 2004 this resistance was detected in E. faecalis as well. At present, more than 70% of the E. faecium isolates show vancomycin resistance; on the contrary, in the case of E. faecalis, this resistance is unusual. Resistance to linezolid or to tigecycline has not been detected in Enterococcus spp. so far.(AU)
Entre os anos 1996 e 2010 estudaram-se 1873 isolamentos de Enterococcus spp. pertencentes a pacientes internados num Hospital Universitário da Cidade Aut¶noma de Buenos Aires com infecþÒo intra-hospitalar. 64,2% e 30,4% dos isolamentos corresponderam a E. faecalis e E. faecium respectivamente. No estudado as infecþ§es por Enterococcus spp. representaram entre 8% e 10% do total das infecþ§es nosocomiais. A prevalÛncia de E. faecium aumentou de 1,5% no ano 1996 para 4% em 2010. O primeiro isolamento de enterococo resistente a vancomicina foi detectado no ano 1998 e correspondeu a um E. faecium e no ano 2004 foi achado em E. faecalis. Atualmente mais de 70% dos isolamentos de E. faecium sÒo resistentes a vancomicina, mas nÒo é assim em E. faecalis onde a resistÛncia é ocasional. NÒo se detectou resistÛncia a linezolid nem a tigeciclina em Enterococcus spp.(AU)
RESUMO
Entre los años 1996 y 2010 se estudiaron 1873 aislamientos de Enterococcus spp. pertenecientes a pacientes internados en un hospital universitario de la Ciudad Autónoma de Buenos Aires con infección intrahospitalaria. El 64,2% y el 30,4% de los aislamientos correspondieron a E. faecalis y E. faecium, respectivamente. En el periodo estudiado las infecciones por Enterococcus spp. representaron entre el 8% y el 10% del total de las infecciones nosocomiales. La prevalencia de E. faecium aumentó de un 1,5% en el año 1996 a un 4% en 2010. El primer aislamiento de enterococo resistente a vancomicina se detectó en el año 1998 y correspondió a un E. faecium y en el año 2004 se halló en E. faecalis. Actualmente más del 70% de los aislamientos de E. faecium son resistentes a vancomicina, no así en E. faecalis donde la resistencia es ocasional. No se detectó resistencia a linezolid ni a tigeciclina en Enterococcus spp.(AU)
Assuntos
Enterococcus , Enterococcus faecium , Infecção Hospitalar , Resistência a VancomicinaRESUMO
Entre los años 1996 y 2010 se estudiaron 1873 aislamientos de Enterococcus spp. pertenecientes a pacientes internados en un hospital universitario de la Ciudad Autónoma de Buenos Aires con infección intrahospitalaria. El 64,2% y el 30,4% de los aislamientos correspondieron a E. faecalis y E. faecium, respectivamente. En el periodo estudiado las infecciones por Enterococcus spp. representaron entre el 8% y el 10% del total de las infecciones nosocomiales. La prevalencia de E. faecium aumentó de un 1,5% en el año 1996 a un 4% en 2010. El primer aislamiento de enterococo resistente a vancomicina se detectó en el año 1998 y correspondió a un E. faecium y en el año 2004 se halló en E. faecalis. Actualmente más del 70% de los aislamientos de E. faecium son resistentes a vancomicina, no así en E. faecalis donde la resistencia es ocasional. No se detectó resistencia a linezolid ni a tigeciclina en Enterococcus spp.
Assuntos
Enterococcus , Enterococcus faecium , Infecção Hospitalar , Resistência a VancomicinaRESUMO
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.
Assuntos
Proteínas de Bactérias/biossíntese , Colistina/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , beta-Lactamases/biossíntese , Proteínas de Bactérias/classificação , Farmacorresistência Bacteriana , Feminino , Humanos , Infecções por Klebsiella/epidemiologia , Masculino , beta-Lactamases/classificaçãoRESUMO
The aims of this study were to evaluate the in vitro activity of extended-spectrum cephalosporins (ESC) in non-inducible AmpC enterobacteria throµgh phenotypic and genotypic characterization of the mechanisms of resistance (ESBL, plasmid-mediated AmpC and KPC) and to evaluate the interpretation criteria proposed by the existing recommendations and the new breakpoints established by the CLSI and the EUCAST. Susceptibility tests and PCR multiplex for b/aSHV and b/aCTX-M and amplification using specific primers was performed. One hundred sixty nine resistant isolates: K/ebsie//a pneumoniae (95), Escherichia co/i (55), and Proteus mirabi/is (19) were recovered. ESC resistance was 56.2 %, 32.6%, and 11.2 %, respectively. ESBL was detected in 152 (90 %) isolates, plasmid-mediated AmpC in 12 (7 %) and KPC in 5 (3 %). The CLSI 2009 recommendations and the breakpoints sµggested by the CLSI 2010 and the EUCAST for ceftriaxone were efficacious to detect ESBL, whereas the different breakpoints for ceftazidime presented discrepancies. The CLSI 2010 breakpoints only detected 55 % of the ESBL-producing isolates due to the endemic presence of CTX-M ESBLs in our country. Regarding the plasmid-mediated AmpC producers, the recommendations of the CLSI 2010 and the EUCAST 2010 proved to be more efficient than the old ones.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefalosporinas/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana/normas , Proteus mirabilis/efeitos dos fármacos , beta-Lactamases/genética , Cefepima , Ceftazidima/farmacologia , Ceftriaxona/farmacologia , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Humanos , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Estudos Prospectivos , Infecções por Proteus/microbiologia , Proteus mirabilis/enzimologia , Proteus mirabilis/genética , Proteus mirabilis/isolamento & purificação , Sociedades Científicas/normasRESUMO
Los objetivos de este estudio fueron determinar la actividad in vitro de las cefalosporinas de espectro extendido frente a aislamientos clínicos de enterobacterias sin AmpC inducible y evaluar la utilidad de las normativas propuestas por el CLSI 2009 y de los puntos de corte recomendados por el CLSI 2010 y el EUCAST 2010. El análisis incluye la caracterización feno y genotípica de los mecanismos de resistencia. En todos los aislamientos se realizó un antibiograma semicuantitativo y se determinó la CIM por dilución en agar. Asimismo, se realizó la detección fenotípica de p-lactamasas de espectro extendido (BLEE), de AmpC plasmídica (AmpCp) y de carbapenemasas de tipo KPC. En los aislamientos que fueron resistentes a las cefalosporinas de espectro extendido (CEE) se evaluó, mediante PCR múltiple para b/aSHV y b/aCTX-M y PCR con cebadores específicos, el tipo de p-lactamasa pre-valente y la presencia de KPC. Se recuperaron de pacientes 169 aislamientos resistentes a CEE: 95 de K/ebsie//a pneumoniae, 55 de Escherichia co/i y 19 de Proteus mirabi/is. La resistencia a CEE se verificó en el 56,2 %; 32,6 % y 11,2 % de estos conjuntos de aislamientos, respectivamente. Se detectó el fenotipo BLEE en 152 aislamientos (90 %), el fenotipo AmpCp en 12 (7 %) y el KPC en 5 (3 %). Las recomendaciones del CLSI 2009 y los puntos de corte del CLSI 2010 y del EUCAST 2010 para la ceftriaxona permitieron detectar eficientemente las BLEE, mientras que para la ceftacidima, con los puntos de corte del CLSI 2010 solo se detectó el 55 % de las BLEE. Esta discrepancia en los porcentajes de resistencia a ceftriaxona y a ceftacidima se relaciona con la presencia de CTX-M en nuestro medio. Los nuevos puntos de corte detectaron con mayor eficiencia las enzimas de tipo AmpCp.(AU)
The aims of this study were to evaluate the in vitro activity of extended-spectrum cephalosporins (ESC) in non-inducible AmpC enterobacteria throAgh phenotypic and genotypic characterization of the mechanisms of resistance (ESBL, plasmid-mediated AmpC and KPC) and to evaluate the interpretation criteria proposed by the existing recommendations and the new breakpoints established by the CLSI and the EUCAST. Susceptibility tests and PCR multiplex for b/aSHV and b/aCTX-M and amplification using specific primers was performed. One hundred sixty nine resistant isolates: K/ebsie//a pneumoniae (95), Escherichia co/i (55), and Proteus mirabi/is (19) were recovered. ESC resistance was 56.2 %, 32.6%, and 11.2 %, respectively. ESBL was detected in 152 (90 %) isolates, plasmid-mediated AmpC in 12 (7 %) and KPC in 5 (3 %). The CLSI 2009 recommendations and the breakpoints sAggested by the CLSI 2010 and the EUCAST for ceftriaxone were efficacious to detect ESBL, whereas the different breakpoints for ceftazidime presented discrepancies. The CLSI 2010 breakpoints only detected 55 % of the ESBL-producing isolates due to the endemic presence of CTX-M ESBLs in our country. Regarding the plasmid-mediated AmpC producers, the recommendations of the CLSI 2010 and the EUCAST 2010 proved to be more efficient than the old ones.(AU)
Assuntos
Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefalosporinas/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana/normas , Proteus mirabilis/efeitos dos fármacos , beta-Lactamases/genética , Ceftazidima/farmacologia , Ceftriaxona/farmacologia , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Estudos Prospectivos , Infecções por Proteus/microbiologia , Proteus mirabilis/enzimologia , Proteus mirabilis/genética , Proteus mirabilis/isolamento & purificação , Sociedades Científicas/normasRESUMO
Los objetivos de este estudio fueron determinar la actividad in vitro de las cefalosporinas de espectro extendido frente a aislamientos clínicos de enterobacterias sin AmpC inducible y evaluar la utilidad de las normativas propuestas por el CLSI 2009 y de los puntos de corte recomendados por el CLSI 2010 y el EUCAST 2010. El análisis incluye la caracterización feno y genotípica de los mecanismos de resistencia. En todos los aislamientos se realizó un antibiograma semicuantitativo y se determinó la CIM por dilución en agar. Asimismo, se realizó la detección fenotípica de p-lactamasas de espectro extendido (BLEE), de AmpC plasmídica (AmpCp) y de carbapenemasas de tipo KPC. En los aislamientos que fueron resistentes a las cefalosporinas de espectro extendido (CEE) se evaluó, mediante PCR múltiple para b/aSHV y b/aCTX-M y PCR con cebadores específicos, el tipo de p-lactamasa pre-valente y la presencia de KPC. Se recuperaron de pacientes 169 aislamientos resistentes a CEE: 95 de K/ebsie//a pneumoniae, 55 de Escherichia co/i y 19 de Proteus mirabi/is. La resistencia a CEE se verificó en el 56,2 %; 32,6 % y 11,2 % de estos conjuntos de aislamientos, respectivamente. Se detectó el fenotipo BLEE en 152 aislamientos (90 %), el fenotipo AmpCp en 12 (7 %) y el KPC en 5 (3 %). Las recomendaciones del CLSI 2009 y los puntos de corte del CLSI 2010 y del EUCAST 2010 para la ceftriaxona permitieron detectar eficientemente las BLEE, mientras que para la ceftacidima, con los puntos de corte del CLSI 2010 solo se detectó el 55 % de las BLEE. Esta discrepancia en los porcentajes de resistencia a ceftriaxona y a ceftacidima se relaciona con la presencia de CTX-M en nuestro medio. Los nuevos puntos de corte detectaron con mayor eficiencia las enzimas de tipo AmpCp.(AU)
The aims of this study were to evaluate the in vitro activity of extended-spectrum cephalosporins (ESC) in non-inducible AmpC enterobacteria throµgh phenotypic and genotypic characterization of the mechanisms of resistance (ESBL, plasmid-mediated AmpC and KPC) and to evaluate the interpretation criteria proposed by the existing recommendations and the new breakpoints established by the CLSI and the EUCAST. Susceptibility tests and PCR multiplex for b/aSHV and b/aCTX-M and amplification using specific primers was performed. One hundred sixty nine resistant isolates: K/ebsie//a pneumoniae (95), Escherichia co/i (55), and Proteus mirabi/is (19) were recovered. ESC resistance was 56.2 %, 32.6%, and 11.2 %, respectively. ESBL was detected in 152 (90 %) isolates, plasmid-mediated AmpC in 12 (7 %) and KPC in 5 (3 %). The CLSI 2009 recommendations and the breakpoints sµggested by the CLSI 2010 and the EUCAST for ceftriaxone were efficacious to detect ESBL, whereas the different breakpoints for ceftazidime presented discrepancies. The CLSI 2010 breakpoints only detected 55 % of the ESBL-producing isolates due to the endemic presence of CTX-M ESBLs in our country. Regarding the plasmid-mediated AmpC producers, the recommendations of the CLSI 2010 and the EUCAST 2010 proved to be more efficient than the old ones.(AU)
Assuntos
Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefalosporinas/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana/normas , Proteus mirabilis , beta-Lactamases/genética , Ceftazidima/farmacologia , Ceftriaxona/farmacologia , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Estudos Prospectivos , Infecções por Proteus/microbiologia , Proteus mirabilis/enzimologia , Proteus mirabilis/genética , Proteus mirabilis/isolamento & purificação , Sociedades Científicas/normasRESUMO
Los objetivos de este estudio fueron determinar la actividad in vitro de las cefalosporinas de espectro extendido frente a aislamientos clínicos de enterobacterias sin AmpC inducible y evaluar la utilidad de las normativas propuestas por el CLSI 2009 y de los puntos de corte recomendados por el CLSI 2010 y el EUCAST 2010. El análisis incluye la caracterización feno y genotípica de los mecanismos de resistencia. En todos los aislamientos se realizó un antibiograma semicuantitativo y se determinó la CIM por dilución en agar. Asimismo, se realizó la detección fenotípica de p-lactamasas de espectro extendido (BLEE), de AmpC plasmídica (AmpCp) y de carbapenemasas de tipo KPC. En los aislamientos que fueron resistentes a las cefalosporinas de espectro extendido (CEE) se evaluó, mediante PCR múltiple para b/aSHV y b/aCTX-M y PCR con cebadores específicos, el tipo de p-lactamasa pre-valente y la presencia de KPC. Se recuperaron de pacientes 169 aislamientos resistentes a CEE: 95 de K/ebsie//a pneumoniae, 55 de Escherichia co/i y 19 de Proteus mirabi/is. La resistencia a CEE se verificó en el 56,2 %; 32,6 % y 11,2 % de estos conjuntos de aislamientos, respectivamente. Se detectó el fenotipo BLEE en 152 aislamientos (90 %), el fenotipo AmpCp en 12 (7 %) y el KPC en 5 (3 %). Las recomendaciones del CLSI 2009 y los puntos de corte del CLSI 2010 y del EUCAST 2010 para la ceftriaxona permitieron detectar eficientemente las BLEE, mientras que para la ceftacidima, con los puntos de corte del CLSI 2010 solo se detectó el 55 % de las BLEE. Esta discrepancia en los porcentajes de resistencia a ceftriaxona y a ceftacidima se relaciona con la presencia de CTX-M en nuestro medio. Los nuevos puntos de corte detectaron con mayor eficiencia las enzimas de tipo AmpCp.
The aims of this study were to evaluate the in vitro activity of extended-spectrum cephalosporins (ESC) in non-inducible AmpC enterobacteria throµgh phenotypic and genotypic characterization of the mechanisms of resistance (ESBL, plasmid-mediated AmpC and KPC) and to evaluate the interpretation criteria proposed by the existing recommendations and the new breakpoints established by the CLSI and the EUCAST. Susceptibility tests and PCR multiplex for b/aSHV and b/aCTX-M and amplification using specific primers was performed. One hundred sixty nine resistant isolates: K/ebsie//a pneumoniae (95), Escherichia co/i (55), and Proteus mirabi/is (19) were recovered. ESC resistance was 56.2 %, 32.6%, and 11.2 %, respectively. ESBL was detected in 152 (90 %) isolates, plasmid-mediated AmpC in 12 (7 %) and KPC in 5 (3 %). The CLSI 2009 recommendations and the breakpoints sµggested by the CLSI 2010 and the EUCAST for ceftriaxone were efficacious to detect ESBL, whereas the different breakpoints for ceftazidime presented discrepancies. The CLSI 2010 breakpoints only detected 55 % of the ESBL-producing isolates due to the endemic presence of CTX-M ESBLs in our country. Regarding the plasmid-mediated AmpC producers, the recommendations of the CLSI 2010 and the EUCAST 2010 proved to be more efficient than the old ones.
