Characterization by PCR of Vibrio parahaemolyticus isolates collected during the 1997-1998 Chilean outbreak

Between November 1997 and April 1998, several human gastroenteritis cases were reported in Antofagasta, a city in the north of Chile. This outbreak was associated with the consumption of shellfish, and the etiologic agent responsible was identified as Vibrio parahaemolyticus. This was the first report of this bacterium causing an epidemic in Chile. V. parahaemolyticus was the only pathogenic bacterium isolated from patient stools and from shellfish samples. These isolates were analyzed by polymerase chain reaction (PCR) amplification of the pR72H gene, a species-specific sequence. Based on the pR72H gene amplification pattern, at least three different isolates of V. parahaemolyticus were found. Two isolates (named amplicons A and C) generated PCR products of approximately 400 bp and 340 bp respectively, while another type of isolate designated B, did not generate a PCR product, regardless of which method of DNA purification was used. Sequence analysis of the amplicons A and C shows that they have an 80 bp and 183 bp conserved region at the 5' end of the gene. However, both isolates have different sequences at their 3' terminus and are also different from the pR72H sequence originally reported. Using this PCR assay we demonstrated that these three isolates were found in clinical samples as well as in shellfish. The warm seawater caused by the climatological phenomena "El Nino" perhaps favored the geographic dispersion of the bacterium (bacterial bloom) occurring in Antofagasta that occurred during that time of year

Documentación bacteriológica de un caso de botulismo infantil / Documentation bacteriology of case of infant botulism

En noviembre de 1994 se recibió en el Laboratorio de Anaerobios del Instituto de Salud Pública de Chile una muestra de deposición de una lactante de dos meses de edad con el diagnóstico presuntivo de botulismo infantil. La muestra fue sembrada en medios de cultivo convenientes y en atmósfera anaerobia hasta obtener un cultivo puro. Este fue sometido a diferentes pruebas bioquímicas que resultaron coincidentes con Clostridium botulinum Grupo I. Posteriormente se procedió a confirmar el diagnóstico realizando exámenes de patogenicidad y neutralización en ratones CF-1. Con base en los resultados observados se concluyó que la cepa aislada correspondía a Clostridium botulinum Grupo I tipo A, lo cual fue confirmado por el Centro para Control de Enfermedades (Centers for Disease Control, CDC) de Atlanta. Este fue le primer aislamiento de C.botulinum a a partir de una muestra clínica en Chile