Usefulness of a Disk Method for Detection of Hippurate Hydrolysis by Campylobacter jejuni / 대한임상미생물학회지

BACKGROUND: The test for hippurate hydrolysis is critical for differentiation of C. jejuni and other thermophilic Campylobacter species. So, we evaluated the disk method for detection of hippurate hydrolysis by C. jejuni. METHODS: Twenty-eight Campylobacter species isolated from stool culture were simultaneously tested with disk method for detection of hippurate hydrolysis and polymerase chain reaction (PCR) for hippuricase specific gene. Disk method was tested with difference in incubation time (2 hours vs. 4 hours), hippurate concentration (1%, 2%, and 4%), amount of ninhydrin (50 microliter vs. 100 microliter), and inoculation method (colony vs. suspension of organism adjusted by turbidity), finally, 24 types of disk methods were performed. RESULTS: By using hippuricase PCR method as the reference for the detection of hippurate hydrolysis, the disk method showed a sensitivity of 91.7% and a specificity of 100% when two kinds of disk methods were simultaneously performed. CONCLUSIONS: The disk method for detection of hippurate hydrolysis is simple to use and require fewer cells than the tube method do, and should be useful as a routine diagnostic test in clinical laboratory for rapid identification of C. jejuni.

A Case of Vibrio cholerae Non-O1/O139 Gastroenteritis / 대한임상병리학회지

Vibrio cholerae non-O1/O139 strains are widely distributed in the environment such as sewage, estuarine waters, seafood, seawater, animals and contaminated foods in Europe, Asia, and the United States. V. Cholerae non-O1/O139 is the etiologic agent of gastroenteritis and extraintestinal infections such as bacteremia and wound infection. Gastroenteritis by Vibrio cholerae non-O1/O139, a prevalent disease in western countries and Asia, is considered rare in Korea. The authors isolated V. cholerae non-O1/O139 from a stool of a 2 year-old male with diarrhea and mild fever. To our knowledge, this is the first documented case of V. cholerae non-O1/O139 gastroenteritis in Korea.

Identification Results of Aerobic Gram-positive Bacteria Isolated from Blood Cultures Using BBL Crystal GP ID System / 대한임상미생물학회지

BACKGROUND: Although most of aerobic gram-positive bacilli have been considered to be contaminants, gram-positive bacilli should be identified to the species level if they are isolated from sterile body sites such as blood, and from adequately collected clinical specimens if they are the predominant organisms. However, identification of gram-positive bacilli are difficult due to the enormous diversity of these organisms and the small number of readily available commercial identification systems in clinical laboratories. Gram-positive bacilli and coccorods isolated from blood cultures were tested with BBL Crystal Gram-Positive (GP) Identification (ID) system in order to evaluate the system's usefulness of identifying these bacteria. METHODS: Thirty-seven stock strains of aerobic gram-positive bacteria isolated from blood cultures between October 1998 and November 1999 at Wonju Christian Hospital were simultaneously tested by BBL Crystal GP ID system and API system. Three kinds of API system (API Coryne, API 50 CHB, and API 20 Strep) were tested according to gram stain results. Gram-positive bacilli or gram-positive coccorods consecutively isolated from blood cultures from May to November in 2000 were identified by BBL Crystal GP ID system. RESULTS: Among the 37 stock strains of aerobic gram-positive bacteria, agreement rate of identification between Crystal GP ID system and API system were 88% to the genus level and 63% to the species level in Bacillus species, and 90% to the genus level in Corynebacterium species. The isolation rate of gram-positive bacteria from blood cultures from May to November in 2000 to the genus level were: Bacillus; 41.9%(18/43), Corynebacterium; 37.2%(16/43), and the other grampositive coccorods; 20.9%(9/43). CONCLUSIONS: Crystal GP ID system is a useful identification system which, when combined with basic microbiological tests, should lead to satisfactory identification results for gram-positive bacteria isolated from blood cultures.