ABSTRACT
Resumen La portación nasal de Staphylococcus aureus representa un riesgo considerable para infecciones tanto nosocomiales como comunitarias. El objetivo del trabajo fue investigar la prevalencia de portación nasal de S. aureus sensibles (SAMS) y resistentes a meticilina (SAMR) en trabajadores de la salud, determinar su asociación con factores epidemiológicos y sus patrones de resistencia a los antimicrobianos. Se tomaron 152 muestras nasales de personal de dos hospitales de la ciudad de Bahía Blanca (Argentina). Los aislados de S. aureus se identificaron por métodos convencionales y por el sistema automatizado BD PhoenixTM 100. La prevalencia de portación nasal de S. aureus fue de 32,2% y, de SAMR, de 12,2%. La frecuencia de portación en el personal de laboratorio (58,8%) resultó estadísticamente significativa. Los aislados fueron sensibles a trimetoprima-sulfametoxazol, cloranfenicol, rifampicina, fluoroquinolonas y vancomicina. Estos datos alertan sobre la necesidad de identificar portadores de S. aureus e implementar estrategias que controlen una potencial diseminación de estos microorganismos.
Abstract The nasal carriage of Staphylococcus aureus represents a considerable risk for both nosocomial and community infections. The objective of this work was to investigate the prevalence of nasal carriage of both methicilin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) in health workers, to determine their association with epidemiological factors and their patterns of antimicrobial resistance. One hundred and fifty-two nasal samples were taken from personnel from two hospitals in the Bahía Blanca city (Argentina). The S. aureus isolates were identified by conventional methods and by the automated BD PhoenixTM 100 system. The prevalence of S. aureus nasal carriage was 32.2% and that of MRSA, 12.2%. The frequency of carrying deterin laboratory personnel was statistically significant (58.8%). The isolates were susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, rifampin, fluoroquinolones and vancomycin. These data warn of the need to identify S. aureus carriers and implement strategies that control the potential spread of these microorganisms.
Resumo O carreamento nasal de Staphylococcus aureus representa um risco considerável para infecções tanto nosocomiais quanto comunitárias. O objetivo do trabalho foi investigar a prevalência de carreamento nasal de S. aureus sensíveis (SAMS) e resistentes à meticilina (SARM) em profissionais da saúde; determinar sua associação com fatores epidemiológicos e seus padrões de resistência aos antimicrobianos. Foram coletadas 152 amostras nasais de funcionários de dois hospitais da cidade de Bahía Blanca (Argentina). Os isolados de S. aureus foram identificados por métodos convencionais e pelo sistema automatizado BD PhoenixTM 100. A prevalência de carreamento nasal de S. aureus foi de 32,2% e a de SARM, de 12,2%. A frequência de carreamento no pessoal do laboratório foi estatisticamente significativa (58,8%). Os isolados foram sensíveis a trimetoprim-sulfametoxazol, cloranfenicol, rifampicina, fluoroquinolonas e vancomicina. Esses dados alertam para a necessidade de identificar portadores de S. aureus e implementar estratégias que controlem a propagação potencial desses microrganismos.
ABSTRACT
Bacterial attachment to fish surfaces and the capacity to compete with pathogens for adhesion sites are essential characteristics in order to select a candidate probiotic for aquaculture. Twelve lactic acid bacteria (LAB) isolated from fish and sediments from Bahía Blanca Estuary, Argentina, were examined for in vitro adhesion to rainbow trout mucus, cell surface properties and competitive exclusion against two salmonid pathogens, Yersinia ruckeri and Aeromonas salmonicida. In order to assess their survival through the digestive tract, pH and rainbow trout bile tolerance were evaluated. All LAB strains survived for 1.5 h incubation in 10% rainbow trout bile. Most of the strains survived 1.5 h at pH 3.0 and three of them showed a reduction of viable counts lower than 2 logarithms, with respect to control (pH 6.5). Only a few strains showed tolerate pH 2.0. All the strains were able to attach to rainbow trout skin mucus (10(4)-10(6) cells/cm(2)), to glass (10(4)-10(5) cells/cm(2)) and to stainless steel (10(3)-10(4) cells/cm(2)). Sixty percent of LAB strains were capable of competing with and successfully excluding Y. ruckeri and all strains were able to displace it. Against A. salmonicida, 75% of LAB strains competed successfully, 50% were capable of displacing and 60% excluded this pathogen. Our data suggest the potential of these strains as anti-infective agents for use in rainbow trout culture. This study is the first report on the probiotic potential of LAB strains isolated from an estuarine environment from Argentina.
