RESUMEN
Serratia marcescens SCH909 is a multidrug resistant strain isolated in 1988 harboring three class 1 integrons. We wondered if these integrons were retained over time and if there were other antimicrobial resistant determinants contributing to its multidrug resistant profile. Genomic analysis showed a fourth multidrug resistance integron, a Tn7 transposon with dfrA1-sat2-ybeA-ybfA-ybfB-ybgA gene cassettes in the variable region. Insertion sequences were involved in the genesis of novel composite transposons in the L4 subtype plasmid pSCH909, such as Tn6824 carrying an arsenic regulon and two head to head class 1 integrons surrounded by two complete IS1. Remarkably, a novel chromosomal genomic island, SmaR, was identified, closely related to Multiple Antimicrobial Resistance Regions (MARR), usually found in AbaR0-type and AbGRI2-0 from global clones of Acinetobacter baumannii, and in M-type plasmids circulating in Enterobacteriaceae. Maintenance studies showed that the three class 1 integrons were maintained over 1 month without antimicrobial pressure. Since S. marcescens is considered a relevant nosocomial pathogen that can have a wide range of niches - human, plant, animal, soil and inanimate surfaces, our findings support the ability of this species to capture, maintain and spread a broad variety of antimicrobial resistance elements.
Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Serratia marcescens/efectos de los fármacos , Serratia marcescens/genética , Acinetobacter baumannii/genética , Animales , Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Enterobacteriaceae/genética , Genes Bacterianos , Genoma Bacteriano/genética , Islas Genómicas/genética , Humanos , Integrones/genética , Plásmidos/genética , Serratia marcescens/aislamiento & purificaciónRESUMEN
In the last few years Acinetobacter baumannii has emerged worldwide as an important nosocomial pathogen in medical institutions. Here, we present the draft genome sequence of the international clonal lineage 1 (ICL1) A. baumannii strain A144 that was isolated in a hospital in Buenos Aires City in the year 1997. The strain is susceptible to carbapenems and resistant to trimethoprim and gentamicin.
Asunto(s)
Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , Serratia marcescens/efectos de los fármacos , Serratia marcescens/genética , beta-Lactamasas/genética , Secuencia de Bases , Transferencia de Gen Horizontal , Humanos , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Plásmidos , Infecciones por Pseudomonas/tratamiento farmacológico , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/aislamiento & purificación , Análisis de Secuencia de ADN , Infecciones por Serratia/tratamiento farmacológico , Infecciones por Serratia/microbiología , Serratia marcescens/aislamiento & purificaciónRESUMEN
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.
Asunto(s)
Infecciones por Enterobacteriaceae/microbiología , Enterobacteriaceae/genética , Genes Bacterianos/genética , Integrones/genética , Argentina , Secuencia de Bases , Infección Hospitalaria/microbiología , Enterobacteriaceae/enzimología , Enterobacteriaceae/aislamiento & purificación , Humanos , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , beta-Lactamasas/genéticaRESUMEN
We have developed a novel typing method based on Vibrio cholerae repeat sequences (VCR) using primers directed out of the VCR sequences. To evaluate the VCR-polymerase chain reaction (PCR) as a typing system, 2 categories, efficacy and efficiency, were analyzed in 69 strains of human and environmental V. cholerae O1 toxigenic and nontoxigenic, and non-O1 strains isolated since 1992-2000 from Argentina. The discriminatory power (0.91), stability (0.95), reproducibility (1), typeability (1), rapidity, accessibility, as well ease of use, indicated that the VCR-PCR method provides an alternative useful tool for molecular epidemiology of V. cholerae. The VCR-PCR of V. cholerae isolates showed 29 patterns, of which pattern 1 represented 68% of the V. cholerae O1 isolates, supporting the hypothesis that a clone with epidemic behavior was responsible for the epidemic in Latin America. These results showed a good correlation and a better epidemiologic analysis when the results were compared in parallel with repetitive extragenic palindromic sequences-PCR. In conclusion, VCR-PCR showed excellent performance as a typing method for cholera surveillance programs.
Asunto(s)
Técnicas de Tipificación Bacteriana , Brotes de Enfermedades , Reacción en Cadena de la Polimerasa/métodos , Secuencias Repetitivas de Ácidos Nucleicos/genética , Vibrio cholerae O1/clasificación , Vibrio cholerae no O1/clasificación , Argentina/epidemiología , Cólera/epidemiología , Cólera/microbiología , ADN Bacteriano/análisis , Microbiología Ambiental , Humanos , Vibrio cholerae O1/genética , Vibrio cholerae O1/aislamiento & purificación , Vibrio cholerae no O1/genética , Vibrio cholerae no O1/aislamiento & purificaciónRESUMEN
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.
Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Genes Bacterianos/genética , Integrones/genética , beta-Lactamasas/genética , Argentina/epidemiología , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/microbiología , Secuencia de Bases , Cartilla de ADN , Humanos , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
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.