RESUMO
The pandemic spread of Vibrio parahaemolyticus is an international public health issue. Because of the outbreak potential of the organism, it is critical to establish an internationally recognized molecular subtyping protocol for V. parahaemolyticus that is both rapid and robust as a means to monitor its further spread and to guide control measures in combination with epidemiologic data. Here we describe the results of a multicenter, multicountry validation of a new PulseNet International standardized V. parahaemolyticus pulsed-field gel electrophoresis (PFGE) protocol. The results are from a composite analysis of 36 well-characterized V. parahaemolyticus isolates from six participating laboratories, and the isolates represent predominant serotypes and various genotypes isolated from different geographic regions and time periods. The discriminatory power is very high, as 34 out of 36 sporadic V. parahaemolyticus strains tested fell into 34 distinguishable PFGE groups when the data obtained with two restriction enzymes (SfiI and NotI) were combined. PFGE was further able to cluster members of known pandemic serogroups. The study also identified quality measures which may affect the performance of the protocol. Nonadherence to the recommended procedure may lead to high background in the PFGE gel patterns, partial digestion, and poor fragment resolution. When these quality measures were implemented, the PulseNet V. parahaemolyticus protocol was found to be both robust and reproducible among the collaborating laboratories.
Assuntos
Técnicas de Tipagem Bacteriana/normas , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado/normas , Epidemiologia Molecular/normas , Vibrio parahaemolyticus/classificação , Vibrio parahaemolyticus/genética , Técnicas de Tipagem Bacteriana/métodos , Análise por Conglomerados , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Genótipo , Humanos , Epidemiologia Molecular/métodosRESUMO
Aeromonas hydrophila, a widely distributed human pathogen causing a variety of diseases, can be isolated from clinical and environmental sources. Analysis in Thailand of 110 isolates of Aeromonas hydrophila by randomly amplified polymorphic DNA-PCR (RAPD-PCR) revealed one specific RAPD pattern group (G) that was associated only with strains from environmental sources. Cytotoxic activity, adhesion to epithelial cells and exoenzyme secretions of A. hydrophila were also investigated. A comparison of isolates with pattern group G with a set of isolates derived from human blood showed low induction of cytotoxicity from those with RAPD pattern group G suggesting low virulence of these strains.
