5 research outputs found
Detección de enterobacterias multirresistentes aisladas en aguas de los rÃos que desembocan en la bahÃa de Guanabara y en muestras de hospitales de RÃo de Janeiro, Brasil
Introduction: The use of antibiotics in humans, animal husbandry and veterinary activities induces selective pressure leading to the colonization and infection by resistant strains.Objective: We evaluated water samples collected from rivers of the Guanabara Bay, which have suffered minor and major environmental degradation, and clinical samples of hospital origin to detect evidence of the presence of resistance genes to aminoglycosides, beta-lactam antibiotics and fluoroquinolones in strains of Klebsiella pneumoniae subsp. pneumoniae, K. pneumoniae subsp. ozaenae and Escherichia coli.Materials and methods: For isolation of the water strains we employed culture media containing 32 μg/ml cephalotin and 8 μg/ml gentamicin. The strains from clinical materials were selected using culture media containing 8 μg/ml gentamicin. The strains were identified and subjected to antimicrobial susceptibility testing (AST), plasmid DNA extraction and polymerase chain reaction (PCR) to detect genes encoding enzymes modifying aminoglycosides (EMA), extended-spectrum beta-lactamases (ESBL) and plasmid mechanisms of quinolone resistance (PMQR).Results: The AST of the isolates recovered from water samples showed multidrugresistance profiles similar to those found in isolates recovered from clinical materials. All isolates from water samples and 90% of the isolates from clinical samples showed at least one plasmid band. In the PCR assays, 7.4% of the isolates recovered from water samples and 20% of those from clinical materials showed amplification products for the three antimicrobial classes.Conclusion: We believe that the detection of microorganisms presenting genetic elements in environments such as water is necessary for the prevention and control of their dissemination with potential to infect humans and other animals in eventual contact with these environments.Introducción. El uso de antibióticos en seres humanos, en la industria pecuaria y en las actividades veterinarias induce una presión selectiva que resulta en la colonización e infección con cepas resistentes.Objetivo. Determinar la presencia de genes de resistencia a aminoglucósidos, betalactámicos y fluoroquinolonas en cepas de Klebsiella pneumoniae subsp. pneumoniae, K. pneumoniae subsp. ozaenae y Escherichia coli, obtenidas de muestras de agua de los rÃos que desembocan en la bahÃa de Guanabara y de muestras clÃnicas de hospitales de RÃo de Janeiro. Materiales y métodos. En la selección de las cepas resistentes obtenidas de las muestras de agua de los rÃos, se emplearon medios de cultivo que contenÃan 32 μg/ml de cefalotina y 8 μg/ml de gentamicina. En el caso de las muestras de especÃmenes clÃnicos, se usaron medios de cultivo que contenÃan 8 μg/ml de gentamicina. Las cepas se identificaron y se sometieron a pruebas de sensibilidad antimicrobiana, extracción de ADN plasmÃdico y pruebas de reacción en cadena de la polimerasa (PCR) para detectar los genes que codifican aquellas enzimas que modifican los aminoglucósidos, las betalactamasas de espectro extendido (BLEE) y los mecanismos de resistencia a las quinolonas mediados por plásmidos.Resultados. Se encontraron perfiles de resistencia a los antimicrobianos similares en los dos grupos. En todas las bacterias obtenidas de las muestras de agua y en 90 % de las muestras clÃnicas, se evidenciaron bandas de plásmidos asociados con la transferencia de genes de resistencia. En las pruebas de PCR, se obtuvieron productos de amplificación de los genes de resistencia para las tres clases de antimicrobianos analizados, en el 7,4 % de las bacterias recuperadas de las muestras de agua y en el 20 % de aquellas recuperadas de las muestras clÃnicas.Conclusión. La detección de microorganismos con elementos genéticos que confieren resistencia a los antibióticos en ambientes como el agua, es una estrategia necesaria para prevenir y controlar la diseminación de estos agentes patógenos con potencial para infectar a humanos y a otros animales en dichos ambientes
The use of antimicrobials in selective coliform media as a tool for quantifying resistant bacteria in aquatic ecosystems in Rio de Janeiro, Brazil
Introduction: Water samples were collected from two areas of the Guanabara Bay, which suffered minor and major environmental degradation. Objective: To isolate the total coliforms (TC) and faecal coliforms (FC) present in the water and to determine the similarity of their multidrug-resistance profiles with the ones found in nosocomial bacteria. Material and Methods: A conventional and a modified most-probable-number (MPN) tests were performed in parallel. The modified test comprised the use of 8mg/ml of gentamicin in each set of EC and Lactose tubes and another set with 32mg/ml cephalothin. The differences on the MPN between the three sets of tubes was then determined. Results: The NMP found in both TC and FC were lower in the set of tubes containing gentamicin when compared with the set of tubes containing cephalothin nevertheless with an exception from the samples belonging to Guaxindiba river (minor environmental degradation area) and Mangue channel (major environmental degradation area) where the MPN of both TC and FC were higher in the set of tubes containing gentamicin. Conclusions: The results obtained in this study suggest that the modified MPN may be a promising technique to assist in the management of hydric resources. This study also raises the issue of wastewater treatment and disposal in hospitals, which have a high level of bacterial selective pressure, being discarded in the vicinity of the area studied here enabling animals and humans to be exposed to treatment challenging pathogenic bacteria