RESUMO
An outbreak of Klebsiella pneumoniae carbapenamase (KPC)-producing K. pneumoniae occurred at our institution. Multiresistant Pseudomonas aeruginosa could have acquired this transmissible resistance mechanism, going unnoticed because its phenotypic detection in this species is difficult. We compared P. aeruginosa isolates obtained before and after the KPC-producing K. pneumoniae outbreak. No bla(KPC) genes were detected in the isolates obtained before the outbreak, whereas 33/76 (43%) of the isolates obtained after the outbreak harboured the bla(KPC) gene. P. aeruginosa may thus become a reservoir of this transmissible resistance mechanism. It is very important to understand the epidemiology of these multiresistant isolates, in order to achieve early implementation of adequate control measures to contain and reduce their dissemination in the hospital environment.
Assuntos
Proteínas de Bactérias/genética , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/isolamento & purificação , Resistência beta-Lactâmica , beta-Lactamases/genética , Argentina/epidemiologia , Surtos de Doenças , Transferência Genética Horizontal , Hospitais de Ensino , Humanos , Infecções por Klebsiella/epidemiologia , Pseudomonas aeruginosa/efeitos dos fármacosRESUMO
The emergence of extended-spectrum ß-lactamases and plasmid-mediated resistance to quinolones has been previously found to be associated with the dissemination of complex class 1 integrons in Argentina. In this study, we analyzed their distribution through time and evaluated the functionality of the Orf513 protein, which is the putative recombinase of the ISCR1 mobile element. We investigated the presence of the orf513, blaCTX-M-2, dfrA3b, qnrB10 and blaDHA-1 genes by PCR and DNA sequencing as well as their linkage to class 1 integrons in 451 non-epidemiologically related nosocomial strains resistant to at least one expanded-spectrum cephalosporin and to one aminoglycoside, isolated between 1989 and 2010 from 7 hospitals from Buenos Aires City. The epidemiology of complex class 1 integrons was found to be notably different among fermenting (94/171) and non-fermenting clinical bacilli isolates (1/280). The ISCR1::qnrB10 positive isolates were found since 1993, confirming its presence in clinical isolates more than a decade before its first description. As expected, In35::ISCR1::blaCTX-M-2 was the most common complex class 1 integron among Enterobacteriaceae isolates, particularly in Proteus mirabilis. Experimental analysis corroborated the activity of the Orf513 protein, which was found to bind specific DNA sequences containing the previously suggested oriIS region. These findings showed the high dispersion and maintenance of complex class 1 integrons across time in our nosocomial isolates. The contribution of the ISCR1 mobile element to multidrug resistant phenotypes is significant due to its sustained association to class 1 integrons.
Assuntos
Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/genética , Genes Bacterianos/genética , Integrons/genética , Argentina , Sequência de Bases , Infecção Hospitalar/microbiologia , Enterobacteriaceae/enzimologia , Enterobacteriaceae/isolamento & purificação , Humanos , Dados de Sequência Molecular , Fases de Leitura Aberta , beta-Lactamases/genéticaRESUMO
Multiple transposons, integrons and carbapenemases were found in Klebsiella pneumoniae colistin-resistant isolates as well as a genomic resistance island of the AbaR type in Acinetobacter baumannii colistin-resistant isolates from different hospitals from Buenos Aires City. PFGE analysis showed a polyclonal dissemination of antimicrobial resistance mechanisms among K. pneumoniae isolates, while in A. baumannii isolates the epidemic clone 1 from South America was found. Resistance determinants associated with horizontal gene transfer are contributing to the evolution to pandrug resistance in both epidemic and sporadic clones.
Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Infecção Hospitalar/microbiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/genética , Acinetobacter baumannii/metabolismo , Antibacterianos/farmacologia , Argentina/epidemiologia , Colistina/farmacologia , Infecção Hospitalar/epidemiologia , Elementos de DNA Transponíveis , Farmacorresistência Bacteriana , Epidemias , Regulação Bacteriana da Expressão Gênica , Hospitais , Humanos , Integrons , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , América do SulRESUMO
The spread of orf513-bearing class 1 integrons is associated with bla(CTX-M-2) in gram-negative clinical isolates in Argentina, with In35 being the most frequently found integron (74%). Among 65 isolates without bla(CTX-M-2), only one harbored a novel orf513-bearing class 1 integron with the dfrA3b gene. The finding of orf513 not associated with class 1 integrons in two gram-positive strains indicates the widespread occurrence of this putative site-specific recombinase.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos/genética , Integrons/genética , beta-Lactamases/genética , Argentina/epidemiologia , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Sequência de Bases , Primers do DNA , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Molecular evolution of multiresistance in nontyphoid Salmonella spp. was investigated with 155 isolates obtained in Argentina from 1984 to 1998. In 74 isolates obtained from 1984 to 1988 resistance was associated with the presence of Tn3, Tn9, class I (In0) and II (Tn7) integrons, and the aac(3)-IIa gene. Extended-spectrum cephalosporin (ESC) resistance in Salmonella spp. emerged in 1989, and 81 isolates resistant to at least one ESC and one aminoglycoside were collected thereafter. Among these, two patterns of antimicrobial resistance mechanisms were found: from 1989 to 1992, resistance was related to the spreading of Tn1331 and bla(CTX-M-2), in addition to the persistence of In0 and Tn7. From 1993 to 1998, several integrons were added to the first pattern and three integron groups (IG), namely, IG1 (38% of the isolates), IG2 (51%), and IG3 (11%), were identified. At least two beta-lactamase genes were detected in 65% of the isolates (after 1989) by PCR analysis. Furthermore, five beta-lactamase genes, bla(CTX-M-(2)), bla(OXA-9), bla(OXA-2), bla(TEM-1), and bla(PER-2), were found in two isolates. The bla(CTX-M-2) gene was found in several complex sulI-type integrons with different rearrays within the variable region of class I integrons, suggesting evolution of these integrons in nontyphoid Salmonella. In conclusion, progressive acquisition and accumulation of plasmid-mediated resistance determinants occurred from 1984 to 1998 in nontyphoid Salmonella isolates of the most prevalent serovars from Argentina. It is suggested that antimicrobial resistance mechanisms in these bacteria may have been the consequence of plasmid exchange between Salmonella enterica serovar Typhimurium and Escherichia coli or Shigella flexneri and/or spreading of mobile elements from the nosocomial environment.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Evolução Molecular , Salmonella/genética , Argentina , Humanos , Fenótipo , Reação em Cadeia da Polimerase , Salmonella/efeitos dos fármacos , Salmonella/isolamento & purificaçãoRESUMO
Examination of the bla(CTX-M-2) gene in plasmid pMAR-12 by sequencing and PCR analysis revealed that the bla gene and the surrounding DNA, which is closely related (99% homology) to the Kluyvera ascorbata chromosomal DNA that contains the bla(KLUA-1) gene, are located in a complex sul1-type integron, termed In35, that includes Orf513. It is possible that bla(CTX-M-2) was acquired by plasmid pMAR-12 through an uncharacterized recombinational event in which Orf513 could be involved.
Assuntos
Genes Bacterianos , beta-Lactamases/genética , Sequência de Bases , Estruturas Genéticas , Dados de Sequência Molecular , Fases de Leitura Aberta , Plasmídeos , Reação em Cadeia da PolimeraseRESUMO
Concluímos que la contrainmunoelectroforesis en la investigación de hepatitis B, fundamentalmente en el caso de portadores (bancos de sangre, servicio de hemodiálisis y personal de alto riesgo), es la técnica recomendada por tener sensibilidad y especificidad aceptables, rapidez y bajo costo
Assuntos
Humanos , Contraimunoeletroforese , Hepatite B/diagnóstico , Antígenos de Histocompatibilidade Classe II , Antígenos de Superfície da Hepatite BRESUMO
Concluímos que la contrainmunoelectroforesis en la investigación de hepatitis B, fundamentalmente en el caso de portadores (bancos de sangre, servicio de hemodiálisis y personal de alto riesgo), es la técnica recomendada por tener sensibilidad y especificidad aceptables, rapidez y bajo costo (AU)