RESUMO
Vibrio parahaemolyticus is an important human pathogen whose transmission is associated with the consumption of contaminated seafood. Consistent multilocus sequence typing for V. parahaemolyticus has shown difficulties in the amplification of the recA gene by PCR associated with a lack of amplification or a larger PCR product than expected. In one strain (090-96, Peru, 1996), the produced PCR product was determined to be composed of two recA fragments derived from different Vibrio species. To better understand this phenomenon, we sequenced the whole genome of this strain. The hybrid recA gene was found to be the result of a fragmentation of the original lineage-specific recA gene resulting from a DNA insertion of approximately 30 kb in length. This insert had a G+C content of 38.8%, lower than that of the average G+C content of V. parahaemolyticus (45.2%), and contained 19 ORFs, including a complete recA gene. This new acquired recA gene deviated 24% in sequence from the original recA and was distantly related to recA genes from bacteria of the Vibrionaceae family. The reconstruction of the original recA gene (recA3) identified the precursor as belonging to ST189, a sequence type reported previously only in Asian countries. The identification of this singular genetic feature in strains from Asia reveals new evidence for genetic connectivity between V. parahaemolyticus populations at both sides of the Pacific Ocean that, in addition to the previously described pandemic clone, supports the existence of a recurrent transoceanic spreading of pathogenic V. parahaemolyticus with the corresponding potential risk of pandemic expansion.
Assuntos
Recombinases Rec A/genética , Vibrioses/microbiologia , Vibrioses/transmissão , Vibrio parahaemolyticus/genética , Biologia Computacional , Ordem dos Genes , Variação Genética , Genoma Bacteriano , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Tipagem de Sequências Multilocus , Oceano Pacífico , Peru , Filogenia , Vibrio parahaemolyticus/classificação , Vibrio parahaemolyticus/isolamento & purificaçãoRESUMO
Vibrio cholerae and V. parahaemolyticus are the two Vibrio species with a major impact on human health. Diseases caused by both pathogens are acquiring increasing relevance due to their expansion at global scale. In this paper, we resume the ecological aspects associated with the arrival and spreading of infections caused by V. parahaemolyticus and V. cholerae in Peru from a South American perspective. Moreover, we discuss the similarities in the emergence in Peru of cholera cases in 1991 and V. parahaemolyticus infections in 1997. These constituted exceptional experiments to evaluate the relationships between the Vibrio epidemics and changes in the environment. The epidemic radiations of V. cholerae and V. parahaemolyticus constitute to clear examples supporting the oceanic dispersion of pathogenic vibrios and have enabled the identification of El Niño events as a potential mechanism for the spreading of diseases through the ocean.
Assuntos
Epidemias , Vibrioses/epidemiologia , Vibrioses/transmissão , Cólera/epidemiologia , Cólera/transmissão , Meio Ambiente , Humanos , Fatores de Risco , América do Sul/epidemiologiaRESUMO
El Vibrio cholerae y el V. parahaemolyticus son las principales especies de Vibrio que ocasionan infecciones en seres humanos. Las infecciones causadas por estos dos patógenos están teniendo una creciente importancia debido a su imparable expansión a nivel mundial. En el presente artículo se resumen los aspectos ecológicos asociados con la llegada y dispersión de las epidemias por V. parahaemolyticus y V. cholera en Perú desde una perspectiva sudamericana. De igual forma, se discute las similitudes en la aparición del cólera en 1991 y las infecciones por V. parahaemolyticus en 1997 en Perú, que sirvieron como experimentos únicos para analizar la relación entre las epidemias de Vibrio y los cambios en el medio ambiente. Estas dos radiaciones epidémicas constituyen unos claros ejemplos que apoyan la teoría de la dispersión oceánica de vibrios patógenos y permiten identificar a los episodios de El Niño como un mecanismo potencial de transmisión de enfermedades a través del océano.
Vibrio cholerae and V. parahaemolyticus are the two Vibrio species with a major impact on human health. Diseases caused by both pathogens are acquiring increasing relevance due to their expansion at global scale. In this paper, we resume the ecological aspects associated with the arrival and spreading of infections caused by V. parahaemolyticus and V. cholerae in Peru from a South American perspective. Moreover, we discuss the similarities in the emergence in Peru of cholera cases in 1991 and V. parahaemolyticus infections in 1997. These constituted exceptional experiments to evaluate the relationships between the Vibrio epidemics and changes in the environment. The epidemic radiations of V. cholerae and V. parahaemolyticus constitute to clear examples supporting the oceanic dispersion of pathogenic vibrios and have enabled the identification of El Niño events as a potential mechanism for the spreading of diseases through the ocean.
Assuntos
Humanos , Epidemias , Vibrioses/epidemiologia , Vibrioses/transmissão , Cólera/epidemiologia , Cólera/transmissão , Meio Ambiente , Fatores de Risco , América do Sul/epidemiologiaRESUMO
The occurrence of bacteria in oysters (Crassotrea rhizophorae) and seawater from Jamaican commercial oyster-culture sites was determined, using standard microbiological methods. Vibrio vulnificus, V. cholerae (non-01, non-toxigenic), V. parahaemolyticus and V. alginolyticus were identified in seawater samples, and the latter two mildly pathogenic species in oysters. The pathogenicity of halophilic vibrios is reviewed. The results suggest that correct selection of oyster-culture sites may significantly reduce the public health hazards associated with shellfish, and that more and precise information is required on the geographical and seasonal distribution of infection risk (AU)