Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
4.
PLoS One ; 13(6): e0198643, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29889876

RESUMEN

The emergence of infections associated to new antimicrobial resistance in Acinetobacter baumannii (Ab) genotypes represents a major challenge. In this context, this study aimed to determine the diversity of resistance mechanisms and investigate clonal dissemination and predominant sequence types (STs) in multidrug-resistant Ab strains of clinical (tracheal aspirate, n = 17) and environmental (surface, n = 6) origins. Additionally, the major clones found in clinical (A) and environmental (H) strains had their complete genomes sequenced. All strains were submitted to polymerase chain reactions (PCR) for the detection of the ISAba1/blaOXA-51-like and ISAba1/blaOXA-23-like genes, while the expression of genes encoding the carO porin, AdeABC (adeB), AdeFGH (adeG), and AdeIJK (adeJ) efflux pumps was determined by real time PCR (qPCR). Most of the strains were characterized as extensively drug-resistant (XDR) with high minimal inhibitory concentrations (MICs) detected for tigecycline and carbapenems. Associations between ISAba1/OXA-51 and ISAba1/OXA-23 were observed in 91.3% and 52.2% of the strains, respectively. Only the adeB gene was considered hyper-expressed. Furthermore, most of the strains analyzed by the MuLtilocus Sequence-Typing (MLST) were found to belong to the clonal complex 113 (CC113). In addition, a new ST, ST1399, belonging to CC229, was also discovered herein. Strains analyzed by whole genome sequencing presented resistance genes linked to multidrug-resistance phenotypes and confirmed the presence of Tn2008, which provides high levels carbapenem-resistance.


Asunto(s)
Acinetobacter baumannii/enzimología , Proteínas Bacterianas/metabolismo , beta-Lactamasas/metabolismo , Acinetobacter baumannii/genética , Secuencia de Aminoácidos , Antibacterianos/farmacología , Proteínas de la Membrana Bacteriana Externa/química , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas Bacterianas/genética , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Porinas/química , Porinas/genética , Alineación de Secuencia , Tigeciclina/farmacología , Secuenciación Completa del Genoma , beta-Lactamasas/genética
5.
Microb Drug Resist ; 24(10): 1441-1449, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29792779

RESUMEN

Carbapenemase-producing organisms are pandemic and a significant threat to public health. We investigated the clonal relatedness of colistin-resistant Klebsiella pneumoniae strains producing KPC-type carbapenemase (KPC-KP) causing subsequent infections or colonization. Moreover, we aimed to gain insight into the ability of biofilm production in K. pneumoniae strains producing carbapenemase. Twenty-two consecutive KPC-KP and one KPC-negative strain was identified from an adult intensive care unit in Brazil. Seventy-five percent of isolates that harbored the blaKPC gene exhibited genetic relatedness by pulsed-field gel electrophoresis, and none presented the plasmid-mediated mcr-1 and blaNDM genes. This study showed that the majority of repeated KPC infections in adults were caused by a clone that caused the previous infections/colonizations even after a long period of time and illustrates the capacity of multiple clones producing biofilms to coexist in the same patient at the same time, becoming a reservoir of KPC-KP in the hospital environment.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Colistina/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , beta-Lactamasas/genética , Adulto , Adhesión Bacteriana , Proteínas Bacterianas/biosíntesis , Biopelículas , Brasil , Recuento de Colonia Microbiana , Infección Hospitalaria/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Humanos , Infecciones por Klebsiella/mortalidad , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/biosíntesis
6.
J Med Microbiol ; 67(4): 523-528, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29509136

RESUMEN

In this study, we describe the frequency of virulence genes in Klebsiella pneumoniae carbapenemase-2-producing Klebsiella pneumoniae (KPC-KP), including hypervirulent (hv) and hypermucoviscous (hm) strains by whole-genome sequencing. We also evaluate the capacity for biofilm formation by using phenotypic techniques. The occurrence of several virulence genes (fimABCDEFGHIK, mrkABCDFHJ, ecpA, wabG, entB, ugE, irp1, irp2, traT, iutA and ureADE) and a high frequency of hvhmKPC-KP isolates was found. Most hospital-associated lineages of KPC-KP belong to the international clonal group 258 (CG258). Biofilm formation was a constant feature among 90.9 % of KPC-KP strains. This report suggests a close relationship between ST437 and weak biofilm production, given that all weakly biofilm-producing strains belonged to this sequence type. This also supports the dissemination of KPC-KP containing numerous virulence determinants belonging to the biofilm-producing CG258 type in Brazil, including hv and hm strains. These factors allow this pathogen to cause infections, leading to its rapid expansion and persistence in hospital settings.


Asunto(s)
Proteínas Bacterianas/metabolismo , Biopelículas , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/enzimología , Klebsiella pneumoniae/patogenicidad , beta-Lactamasas/metabolismo , Proteínas Bacterianas/genética , Brasil , Humanos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/fisiología , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/genética
8.
J Med Microbiol ; 66(8): 1144-1150, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28771139

RESUMEN

Plasmid-mediated quinolone resistance (PMQR) determinants combined with mutations in quinolone resistance-determining regions (QRDRs) and clonal dissemination were investigated in 40 fluoroquinolone-resistant Klebsiella pneumoniae and Escherichia coli isolates from nosocomial and community-acquired infections. We observed nucleotide substitutions in gyrA (Ser83Ile, Val37Leu, Lys154Arg, Ser171Ala, Ser19Asn, Ile198Val, Ser83Tyr, Ser83Leu, Asp87Asn and Asp87Gly) and parC genes (Ser80Ile, Glu84Lys, Ala129Ser, Val141Ala and Glu84Gly). Two novel substitutions were detected in the gyrA gene (Val37Leu and Ile198Val). The presence of PMQR genes predominated in community isolates (55.5 %). In addition to the frequent presence of the class 1 integron in isolates from community-acquired infections, the genetic similarity results obtained by PFGE showed high genomic diversity. This study suggests that management of multidrug-resistant Enterobacteriaceae isolates from the community are a possible source of genetic mobile elements that carry genes that confer resistance to fluoroquinolones. More attention should be paid to the surveillance of community-acquired infections.

9.
PLoS One ; 12(5): e0176774, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28481953

RESUMEN

The bacterial factors associated with bacteremia by multidrug-resistant and extensively drug-resistant P. aeruginosa, including overexpression of efflux pumps, AmpC overproduction, and loss/alteration of the OprD porin in isolates that are non-Metallo-ß-Lactamase producing were analyzed in a retrospective study. Molecular analyses included strain typing by Pulsed Field Gel Electrophoresis and identification of key genes via qualitative and quantitative PCR-based assays. Previous use of carbapenems and tracheostomy was independently associated with the development of bacteremia by extensively drug-resistant and multidrug-resistant strains of P. aeruginosa. A high consumption of antimicrobials was observed, and 75.0% of the isolates contained amplicons with the blaSPM-1 and blaVIM genes. Of the 47 non-Metallo-ß-Lactamase isolates, none had another type of carbapenemase. However, the isolates exhibited high rates of hyperproduction of AmpC, loss of the OprD porin (71.4%) and the presence of MexABOprM (57.1%) and MexXY (64.3%). This study suggests that in non-Metallo-ß-Lactamase isolates, the association of intrinsic resistance mechanisms could contributes to the expression of multidrug-resistant/extensively drug-resistant phenotypes.


Asunto(s)
Bacteriemia/genética , Bacteriemia/microbiología , Farmacorresistencia Microbiana/genética , Epidemiología Molecular , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena en Tiempo Real de la Polimerasa , Estudios Retrospectivos , Adulto Joven
10.
PLoS One ; 11(5): e0155914, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27219003

RESUMEN

We described a comprehensive analysis of the molecular epidemiology of multidrug-resistant (MDR) P. aeruginosa. Molecular analysis included typing by Pulsed Field Gel Electrophoresis, identification of genes of interest through PCR-based assays and sequencing of target genes. Case-control study was conducted to better understand the prognostic of patients and the impact of inappropriate therapy in patients with bacteremia, as well as the risk factors of MDR infections. We observed a high rate of MDR isolates (40.7%), and 51.0% of them was independently associated with inappropriate antibiotic therapy. Bacteremia was detected in 66.9% of patients, and prolonged hospital stay was expressive in those resistant to fluoroquinolone. Plasmid-mediated quinolone resistance genes (PMQR), qnrS1 and aac(6')Ib-cr, were detected in two different nosocomial isolates (5.3%), and the aac(6')-Ib7 variant was detected at a high frequency (87.5%) in those negative to PMQR. The presence of mutations in gyrA and parC genes was observed in 100% and 85% of selected isolates, respectively. Isolates harboring PMQR genes or mutations in gyrA and parC were not closely related, except in those containing SPM (São Paulo metallo-ß-lactamase) clone. In addition, there is no study published in Brazil to date reporting the presence of Pseudomonas aeruginosa isolates harboring both qnrS1 and aac(6')Ib-cr genes, with alarming frequency of patients with inappropriate therapy.


Asunto(s)
Bacteriemia/epidemiología , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana Múltiple , Infecciones por Pseudomonas/epidemiología , Pseudomonas aeruginosa/clasificación , Adulto , Anciano , Bacteriemia/tratamiento farmacológico , Técnicas de Tipificación Bacteriana , Brasil/epidemiología , Estudios de Casos y Controles , Femenino , Fluoroquinolonas/farmacología , Fluoroquinolonas/uso terapéutico , Hospitalización/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Tipificación Molecular , Pronóstico , Infecciones por Pseudomonas/tratamiento farmacológico , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética
11.
Curr Microbiol ; 72(5): 617-27, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26846651

RESUMEN

The emergence of Acinetobacter baumannii and Klebsiella pneumoniae strains in the hospital environment has been associated with the presence of multiple genetic elements, virulence factors and the ability to form biofilms. This study evaluated the biofilm formation ability of clinical and environmental A. baumannii and K. pneumoniae strains, isolated from various sources and presenting different molecular characteristics, resistance profiles and pulsed-field gel electrophoresis patterns. Fifty-three isolates were recovered from 2009 to 2014 in a Brazilian university hospital. Investigation of biofilm formation was performed for 10 strains of each species assessed by an initial adhesion assay, biofilm cell concentration and biofilm biomass, evaluated by quantitative assays in replicates, in three independent experiments. All strains of A. baumannii were able to attach to polystyrene plates, although two strains adhered to a lesser degree than the control. K. pneumoniae strains showed opposite behaviour, where only three strains adhered significantly when compared to the control. Quantitative evaluation revealed that in five A. baumannii and four K. pneumoniae isolates the biomass production could be characterised as moderate. None of the isolates were strong biofilm producers. Our results demonstrate: (1) biofilm formation is a heterogeneous property amongst A. baumannii and K. pneumoniae clinical strains and it was not associated with certain clonal types; (2) no relationship between multidrug resistance and biofilm production was observed; (3) more virulent K. pneumoniae strains tended to present higher production of biofilm.


Asunto(s)
Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple , Klebsiella pneumoniae/efectos de los fármacos , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/genética , Acinetobacter baumannii/fisiología , Adhesión Bacteriana/efectos de los fármacos , Brasil , Humanos , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/aislamiento & purificación , Klebsiella pneumoniae/fisiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...