RESUMEN
During 2005, 66 carbapenem-resistant isolates of Acinetobacter baumannii were collected from seven tertiary-care hospitals participating in a nationwide surveillance network in Colombia. The isolates were multidrug resistant and produced the carbapenemases OXA-23 and OXA-51. Forty-five belonged to four clones while 21 were unique pulsotypes. One clone was present in two hospitals within one city, while another had spread between two hospitals in different cities. Blood, secretions, and abdominal fluids were the most frequent sites of isolation. This is the first description of widespread dissemination of OXA-23 in South America.
Asunto(s)
Infecciones por Acinetobacter/epidemiología , Acinetobacter baumannii/genética , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Hospitales , beta-Lactamasas/genética , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/clasificación , Acinetobacter baumannii/efectos de los fármacos , Proteínas Bacterianas/metabolismo , Carbapenémicos/farmacología , Colombia/epidemiología , Humanos , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Vigilancia de la Población , Resistencia betalactámica , beta-Lactamasas/metabolismoRESUMEN
In Medellin, Colombia, three Pseudomonas aeruginosa isolates with high-level carbapenem resistance (MIC>or=256 microg/ml) and an isolate of Citrobacter freundii with reduced susceptibility to imipenem produced the plasmid-mediated class A carbapenemase KPC-2. This is the first report of a KPC-type beta-lactamase identified outside of the family Enterobacteriaceae.
Asunto(s)
Farmacorresistencia Bacteriana/genética , Pseudomonas aeruginosa/enzimología , beta-Lactamasas/metabolismo , Carbapenémicos/metabolismo , Carbapenémicos/farmacología , Hidrólisis , Pruebas de Sensibilidad Microbiana , Pseudomonas aeruginosa/genética , beta-Lactamasas/genéticaRESUMEN
The plasmid-mediated class A carbapenemase KPC-2 was isolated from unrelated Klebsiella pneumoniae isolates in Medellin, Colombia. These KPC enzymes are the first from South America and the second isolation outside of the United States. The expanding geographic spread of KPC carbapenemases underscores the importance of clinical recognition of these enzymes.
Asunto(s)
Proteínas Bacterianas/genética , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Plásmidos/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Proteínas Bacterianas/clasificación , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana/genética , Humanos , Punto Isoeléctrico , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimología , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , América del Sur/epidemiología , beta-Lactamasas/clasificación , beta-Lactamasas/metabolismoRESUMEN
Carbapenem resistance rates in Pseudomonas aeruginosa isolates in Colombia, as in many South American countries, are high for reasons that remain unclear. From our nationwide network, we describe the first detection of the metallo-beta-lactamase VIM-2 in clinical isolates of P. aeruginosa from multiple cities within Colombia. Metallo-beta-lactamases were not detected in the two centers with the highest imipenem resistance rates. Clonality was noted in five of the eight centers with strains meeting the criteria for molecular typing. The high carbapenem resistance in P. aeruginosa in Colombia may be attributable to a combination of factors, including the presence of metallo-beta-lactamases and nosocomial transmission.
Asunto(s)
Imipenem/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Resistencia betalactámica , beta-Lactamasas/análisis , Colombia , Hospitales , Pseudomonas aeruginosa/enzimología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/aislamiento & purificación , beta-Lactamasas/genéticaRESUMEN
Gram-negative bacilli remain major killers of hospitalized patients and continue to evolve new resistance mechanisms. This review describes the mechanisms of resistance to beta-lactam antibiotics from those Gram-negative pathogens most often isolated from nosocomial infections.
Asunto(s)
Infección Hospitalaria/tratamiento farmacológico , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Resistencia betalactámica/genética , beta-Lactamas/uso terapéutico , Animales , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infección Hospitalaria/genética , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/genética , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Resistencia betalactámica/efectos de los fármacos , beta-Lactamas/farmacologíaRESUMEN
We describe the detection of the CTX-M-12 beta-lactamase from a clinical isolate of Klebsiella pneumoniae in Colombia. Screening of nosocomial Klebsiella spp. and Escherichia coli isolates from a network of teaching hospitals revealed the presence of CTX-M enzymes in multiple cities. This is the first description of CTX-M in Colombia.
Asunto(s)
Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/enzimología , beta-Lactamasas/química , beta-Lactamasas/genética , Colombia/epidemiología , Infección Hospitalaria/microbiología , Sondas de ADN , Farmacorresistencia Bacteriana , Humanos , Focalización Isoeléctrica , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , beta-Lactamasas/aislamiento & purificaciónRESUMEN
A collection of Aspergillus fumigatus mutants highly resistant to itraconazole (RIT) at 100 micro g ml(-1) were selected in vitro (following UV irradiation as a preliminary step) to investigate mechanisms of drug resistance in this clinically important pathogen. Eight of the RIT mutants were found to have a mutation at Gly54 (G54E, -K, or -R) in the azole target gene CYP51A. Primers designed for highly conserved regions of multidrug resistance (MDR) pumps were used in reverse transcriptase PCR amplification reactions to identify novel genes encoding potential MDR efflux pumps in A. fumigatus. Two genes, AfuMDR3 and AfuMDR4, showed prominent changes in expression levels in many RIT mutants and were characterized in more detail. Analysis of the deduced amino acid sequence encoded by AfuMDR3 revealed high similarity to major facilitator superfamily transporters, while AfuMDR4 was a typical member of the ATP-binding cassette superfamily. Real-time quantitative PCR with molecular beacon probes was used to assess expression levels of AfuMDR3 and AfuMDR4. Most RIT mutants showed either constitutive high-level expression of both genes or induction of expression upon exposure to itraconazole. Our results suggest that overexpression of one or both of these newly identified drug efflux pump genes of A. fumigatus and/or selection of drug target site mutations are linked to high-level itraconazole resistance and are mechanistic considerations for the emergence of clinical resistance to itraconazole.