Molecular Epidemiology of Clostridium perfringens Isolated from Food Poisoning in Seoul, 2013

Clostridium perfringens food poisoning ranks among the most common gastrointestinal diseases in developed countries. In Korea, C. perfringens food poisoning gradually increases. Using PCR, 72 strains of C. perfringens isolated in Seoul, 2013 were tested for the presence of toxin genes. Of the tested strains, 32 isolates carried the cpe gene, 37 isolates carried the cpb2 gene and 3 isolates carried the cpe and cpb2 genes, respectively. 32 cpe-positive strains were isolated from the food poisoning patient, whereas among 37 cpb2-positive strains, 22 strains were isolated from asymptomatic person. To investigate epidemiological relationship between the isolates, Pulsed-filed gel electrophoresis (PFGE) was performed. The genetic relatedness of the isolates ranged from 55.9% to 100% and 47 distinct PFGE profiles were observed. The results show that the cpe-positive outbreak strains showed close genetic relation, whereas the cpb2-positive isolates revealed a wide genetic diversity.

Epidemiological Relationship of Enterotoxigenic Escherichia coli and Enteroaggregative E. coli Isolated from Patients with Diarrhea in Seoul

Of total 1,438 specimens of patients with diarrhea in Seoul, 2011, 217 samples (15%) were found pathogenic Escherichia coli that included 192 strains (89%) of enterotoxigenic E. coli (ETEC) and enteroaggregative E. coli (EAEC). The highest isolation rate for ETEC and EAEC was found in August and September. Sixty two pathogenic E. coli strains (34 ETEC and 28 EAEC strains) were selected from 175 strains (94 ETEC and 81 EAEC strains) isolated in August and September. Of 94 strains characterized for ETEC phenotype, 76 (81%) expressed heat-stable toxin (ST) only. Antimicrobial susceptibility test was carried out by using sixteen types of antibiotics. A high level of antimicrobial resistance to tetracycline (57%), ampicillin and ticarcillin (54%) was observed among EAEC isolates while the highest resistance rate of ETEC was found for nalidixic acid (47%), followed by tetracycline (32%). As to the antimicrobial susceptibility test, EAEC showed the complicated multi-drug resistant patterns in which the resistance was higher than ETEC. Pulsed-field gel electrophoresis (PFGE) was carried out to examine the genetic relatedness among ETEC and EAEC isolates. Except for 11 strains, 51 strains were divided by eight pulsotypes. In PFGE analysis, isolates from foodborne disease outbreaks in August and September 2011 showed close relation.