Conventional and molecular diagnosis of clostridium difficile infections in a tertiary care hospital

Abstract

Introduction: Indiscriminate use of broad-spectrum antibiotics has dramatically increased the incidence of Clostridium difficile-associated diarrhea (CDAD) in recent years. It is the most common cause of antibiotic-associated diarrhea (AAD) responsible for one-third of AAD cases. Aim: The aim was to study C. difficile in AAD. Objectives: The objectives were to study the prevalence of CDAD, to isolate C. difficile from AAD, and to study the molecular detection of toxin-producing strains of C. difficile. Materials and Methods: A total of 222 patients of AAD were assessed for C. difficile over a period of 2 years. Anaerobic culture for C. difficile was done on cycloserine-cefoxitin-fructose agar and brain–heart infusion agar. Enzyme-linked immunosorbent assay (ELISA) for toxin A and toxin B was used for detecting toxigenic strains of C. difficile. Identification of C. difficile and toxin-producing strains was done with the help of polymerase chain reaction (PCR). Observation and Results: Out of the total 222 cases of AAD, 20 (9%) were positive by culture and 70 (31.53%) were found to be toxin-producing C. difficile by ELISA. C. difficile was positive by PCR in 32 (14.41%); of these, 18 (56.25%) isolates were toxigenic, i.e., they possessed either the tcdA or the tcdB gene or both. Among the toxigenic isolates, 10 (31.25%) possessed both of the toxigenic genes (tcdA and tcdB) and the remaining 8 (25%) had one of the toxin genes. Only the toxin A (tcdA+ tcdB-) gene was found in 4 (12.5%) and only the toxin B (tcdA- tcdB+) gene in 4 (12.5%) of the toxigenic isolates. Conclusion: CDAD is an emerging nosocomial infection. Frequent and indiscriminate use of antibiotics has increased the prevalence of C. difficile infection. Conventional and molecular diagnosis can help to accurate diagnosis of these infections.