Ecoepidemiology of Laribacter hongkongensis, a Novel Bacterium

In a territory-wide surveillance study, Laribacter hongkongensis was isolated solely from freshwater fish (60% of grass carps, 53 % of bighead carps, and 25 % of mud carps). Comparing the pulsed-field gel electrophoresis patterns of fish and patient isolates revealed that most patient isolates were clustered together, suggesting that some clones could be more virulent. Laribacter hongkongensis was first discovered in Hong Kong from the blood and empyema pus of a 54-year-old Chinese man with alcoholic cirrhosis (5). Subsequently, L. hongkongen-sis was discovered in three of our patients and three patients in Switzerland with community-acquired gastroenteritis (3). In a multicenter prospective study, we confirmed that L. hongkon-gensis is associated with community-acquired gastroenteritis and traveler’s diarrhea (4). Freshwater fish were shown to be a reservoir of L. hongkongensis (4). The isolation of L. hongkon-gensis from patients who resided in or have recently traveled to Asia, Europe, America, and Africa implied that the bacterium is likely to be of global importance. In this study, in order to determine the prevalence of L. hongkongensis in different animals commonly used for cooking in our locality, we carried out an ecoepidemiology study in Hong Kong. Furthermore, to determine the genetic diversity of L. hongkongensis, all L. hongkongensis isolates were typed by pulsed-field gel electrophoresis (PFGE). The PFGE patterns were compared to those of L. hongkongensis strains isolated from patients with gastroenteritis. Fecal swabs were obtained from 350 pigs and 80 cows, and cloacal swabs were obtained from 400 chickens, 50 ducks, and 50 geese from slaughter houses and poultry farms in Hong Kong with assistance from Veterinary Public Health Section o