Cost-effective screening of pooled faecal specimens from patients with nosocomial diarrhoea for Clostridium perfringens enterotoxin

Purpose: Clostridium perfringens is a significant cause of nosocomial AAD. The prevalence of C. perfringens enterotoxin (CPE)-positive stool specimens in hospitalised patients is very low in the Indian setting making the diagnostics very expensive. Therefore, a cost-effective diagnostic approach to screen faecal specimens for CPE was devised.
Materials and Methods: Faecal specimens from 540 hospitalised patients with various ailments and from 340 healthy subjects were investigated for CPE. An aliquot of pooled faecal supernatants was made by mixing 100 μl each of 10 specimens to be tested. Each aliquot was investigated for the presence of CPE by an enzyme immunoassay. A repetition of the assay was done with individual specimens of the pooled aliquots from each positive well as seen visually by colour development.
Results: Of the 540 patient specimens tested, 405 (75%) patients were on antibiotics, the predominant ones being cephalosporins, penicillin, quinolones, aminoglycosides, etc. During the time of sampling, diarrhoea was present in 481 (89%), abdomen pain in 203 (37.6%) and fever in 242 (44.8%) patients. C. perfringens enterotoxin was positive in nine wells of the 540 pooled test specimens whereas all of the pooled 340 control samples were negative. Repeat of individual specimens comprising the nine wells with positive samples helped to identify the individual patients positive for CPE.
Conclusion: Only two CPE kits were needed for a total of 880 faecal specimens tested. The cost-effective diagnostic approach to screen faecal specimens for CPE, as described herein will help to save institutional resources.

Keywords
C. perfringens enterotoxin, cost-effective method, nosocomial diarrhoea