Direct Application of Multiplex PCR on Stool Specimens for Detection of Enteropathogenic Bacteria

Background: Causative bacterial agents of infectious diarrheal disease were traditionally diagnosed by stool cultures. Stool culture, however, has a problem because of relatively low sensitivity and long turnaround time. In this study, we evaluated multiplex PCR applied on stool specimens directly to diagnose enteropathogenic bacteria. Methods: From June to September 2009, 173 diarrheal stools submitted for stool cultures were tested by SeeplexR Diarrhea ACE Detection kit (Seegene, Korea) to detect 10 enteropathogenic bacteria. Specimens were cultured for Salmonella, Shigella, Vibrio, and Yersinia. Late 50 specimens were also cultured for Campylobacter. The specimens positive for verotoxin-producing Escherichia coli (VTEC) were further subcultured for detecting enterohaemorrhagic Escherichia coli O157:H7. Electronic medical records were reviewed for clinical and laboratory findings. Results: Of 173 specimens, multiplex PCR and cultures identified enteropathogens in 36 (20.8%) and 8 specimens (4.6%), respectively. While multiplex PCR detected 5 Salmonella, 15 Campylobacter, 1 Vibrio, 4 Clostridium difficiles toxin B, 5 Clostridium perfringens, 1 Yersinia enterocolitica, 5 Aeromonas, and 2 VTEC, cultures detected 5 Salmonella, 1 Vibrio, 1 Y. enterocolitica, 1 Aeromonas, and 2 E. coli O157:H7. Conclusion: Multiplex PCR would be useful to detect Campylobacter, VTEC and C. perfringens, as well as have equivalent sensitivity to conventional culture for ordinary enteropathogens such as Salmonella, Shigella, Vibrio, Y. enterocolitica. Direct application of multiplex PCR combined with conventional cultures on stool warrants remarkable improvement of sensitivity to diagnose enteropathogenic bacteria. (Korean J Clin Microbiol 2010;13:162-168)