Epidemiology ofVibrio parahaemolyticusOutbreaks, Southern Chile

• DOI: 10.3201/eid1502.071269
• Publication Date: 2009-02-02T22:27:57Z
• Authors: Erika Harth; Luis Matsuda; Cristina Hernández; Maria L. Rioseco; Jaime Romero; Narjol González-E...; Jaime Martínez-Ur...; Romilio T. Espejo
• Keywords: Microbiology (medical); 0301 basic medicine; Epidemiology; Molecular Sequence Data; Infectious and parasitic diseases; RC109-216; Polymerase Chain Reaction; Disease Outbreaks; 03 medical and health sciences; Animals; Humans; Chile; Serotyping; Shellfish; research; lateral transfer; Research; R; Sequence Analysis, DNA; shellfish; Infectious Diseases; outbreaks; Vibrio Infections; Medicine; Vibrio parahaemolyticus

Disease outbreaks caused by Vibrio parahaemolyticus in Puerto Montt, Chile, began in 2004 and reached a peak in 2005 at 3,600 clinical cases. Until 2006, every analyzed case was caused by the serovar O3:K6 pandemic strain. In the summer of 2007, only 475 cases were reported; 73% corresponded to the pandemic strain. This decrease was associated with a change in serotype of many pandemic isolates to O3:K59 and the emergence of new clinical strains. One of these strains, associated with 11% of the cases, was genotypically different from the pandemic strain but contained genes that were identical to those found on its pathogenicity island. These findings suggest that pathogenicity-related genes were laterally transferred from the pandemic strain to one of the different V. parahaemolyticus groups comprising the diverse and shifting bacterial population in shellfish in this region.