Comparison between O serotyping method and multiplex real-time PCR to identify diarrheagenic Escherichia coli in Taiwan.

To compare the diarrheagenic Escherichia coli (DEC) identifications obtained between traditional O serotyping and modern virulence gene detection assays, we developed a multiplex real-time PCR assay by detecting six specific virulence genes for enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enterotoxigenic E. coli (ETEC), and enteroinvasive E. coli (EIEC). Among 261 clinical diarrheal stool samples, a total of 137 suspected DEC (sDEC) isolates were identified by the use of commercially available antisera. The most prevalent serogroups were O1 (12/137; 8.7%), O25 (9/137; 6.5%), and O44 (9/137; 6.5%). The specific virulence genes for the 137 sDEC isolates were analyzed by the multiplex real-time PCR assay. Fifteen (10.9%) of 137 isolates were confirmed to be true DEC strains, indicating that the serotypic markers did not correlate with the specific virulence genes. ETEC (66.7%) was the most prevalent, followed by EIEC (20%) and EPEC (13.3%). No EHEC strains were identified in the specimens. Four novel serotypes were found in the study: two in EPEC strains (O111:H9 and O63:H6) and two in EIEC strains (O63:H9 and O169:H9). In conclusion, the real-time PCR assay considerably reduces the high false-positive rate from the use of serotyping alone, and thus, it is suggested that serogrouping-based methods are inadequate for the identification of DEC isolates, although they are useful for the identification of a limited number of serogroups. In addition, ETEC, EPEC, and EIEC strains were present in 5.7% (15/261) of the diarrheal patients in northern Taiwan in 2006.

Bacterial food-borne illness outbreaks in northern Taiwan, 1995-2001.

How to reduce the occurrence of food-borne illness has always been one issue of great importance in Taiwan's disease prevention and control efforts, and it is important to determine, from survey results, whether the pathogens in Taiwan are the same or different from those in other countries. Accordingly, data on 1171 food-borne illness outbreaks were collected from the Center for Disease Control (CDC) of the Department of Health in Taiwan. The patients and the cases were numbered according to the guidelines and definition of food poisoning given by the Department of Health in Taiwan. All rectal swabs for culture were collected from the CDC. During 1995 to 2001, 1171 outbreaks of food-borne illness, including 109,884 cases, were reported in northern Taiwan, of which 735 (62.8%) were caused by bacterial infection. Bacterial pathogens, particularly Vibrio parahaemolyticus (86.0%), Staphylococcus aureus (7.6%), and Salmonella spp. (4.9%) were the main etiologic agents. The responsible pathogens in Taiwan appeared to be quite different from those in Europe and the United States. It is important to establish a unique surveillance net of our own to prevent and control our situation of food-borne disease outbreaks effectively.

Bacteremic necrotizing fasciitis caused by Vibrio cholerae serogroup O56 in a patient with liver cirrhosis.

Bacteremic necrotizing fasciitis caused by non-O1 Vibrio cholerae has rarely been reported. We describe a case of necrotizing fasciitis of the bilateral lower extremities in a 68-year-old man with liver cirrhosis and diabetes mellitus. Cultures of blood and the debrided tissue all yielded V. cholerae serogroup non-O1 (O56). Despite extensive radical debridement and antibiotic treatment with ceftazidime and doxycycline, the patient died on the 12th hospital day due to multiple organ failure. The present case is the first report of necrotizing fasciitis and bacteremia caused by V. cholerae serogroup O56.