Surveillance of Bacillus cereus Isolates in Korea from 2012 to 2014

OBJECTIVES: To investigate the prevalence and toxin production characteristics of non-emetic and emetic Bacillus cereus strains isolated via the laboratory surveillance system in Korea. METHODS: A total of 667 B. cereus strains were collected by the Korea National Research Institute of Health laboratory surveillance system from 2012 to 2014. The collected strains were analyzed by geographical region, season, patient age, and patient sex. Additionally, the prevalence rates of enterotoxin and emetic toxin genes were evaluated. RESULTS: The isolation rate of B. cereus strains increased during the summer, but the isolation rate was evenly distributed among patient age groups. Emetic toxin was produced by 20.2% of the isolated strains. The prevalence rates of five enterotoxin genes (entFM, nheA, cytK2, hblC, and bceT) were 85.0, 78.6, 44.5, 36.6, and 29.7%, respectively, among non-emetic strains and 77.8, 59.3, 17.8, 11.9 and 12.6%, respectively, among emetic strains. Thus, the prevalence rates of all five enterotoxin genes were lower in emetic B. cereus. CONCLUSION: The prevalence of enterotoxin genes differed between non-emetic and emetic B. cereus strains. Among emetic B. cereus strains, the prevalence rates of two enterotoxin genes (cytK2 and hblC) were lower than those among the non-emetic strains. In both the emetic and non-emetic strains isolated in Korea, nheA and entFM were the most prevalent enterotoxin genes.

The Prevalence and Characteristics of Bacteria Causing Acute Diarrhea in Korea, 2012 / 대한임상미생물학회지

BACKGROUND: Through change in the climate and living environment, bacterial pathogens that cause diarrhea also change. This study sought to determine the characteristics of pathogens according to species, isolated region, and patient age/sex using National Surveillance Data for diarrhea, and to provide basic data for the prevention of diarrheal disease. METHODS: From January to December 2012, stool specimens were collected from 21,180 diarrheal patients in Korea to identify the pathogenic bacteria involved. Pathogenic bacteria were analyzed according to isolated region and patient age/sex. Identification and analysis of the pathogens were conducted based on the Guidelines of the National Institute of Health Diagnostic Laboratory: Disease-specific protocol (2005). RESULTS: Among the 21,180 stool specimens, pathogenic bacteria known to cause diarrhea were isolated from 2,444 stool specimens (11.5%). The isolation rate was highest in the summer (from June to September) for most pathogenic bacteria, except Escherichia coli, Staphylococcus aureus, and Clostridium perfringens. The isolation rate of pathogenic bacteria based on patient age was highest in children under the age of 10. CONCLUSION: Hygiene education should be addressed in diarrheal disease-susceptible groups, such as children under 10, people in their 50s, and those greater than 70 years old, and ongoing monitoring for pathogens is needed. In addition, an efficient information system and surveillance program should be continued for infection prevention.