Evaluation of Real Time Polymerase Chain Reaction and Enzyme Immunoassay in Diagnosis of Clostridium Difficile Infection

Abstract

Background: Clostridium difficile infection (CDI) is the most common cause of antibiotic associated diarrhea (AAD). Rapid diagnosis of CDI is essential to prevent hospital spread of infection. Objectives: The aim of this work were to determine the prevalence of CDI among cases of AAD in Zagazig University Hospitals, identify risk factors, and evaluate real-time polymerase chain reaction (PCR) and enzyme immunoassay (EIA), against toxigenic culture (TC). Methodology: Stools were collected from 150 patients with AAD. Results: They were tested for TC, toxin A/B EIA, and C. difficile tcdA/tcdB genes. Thirty four toxigenic C. difficile isolates were obtained (22.7%) out of the 150 patients and those patients were considered positive for CDI. On the other hand, 6 non-toxigenic C. difficile isolates were obtained (4%), while culture of the remaining 110 patients (73.3%) did not yield C. difficile. The later 116 patients (77.3%) were considered negative for CDI. Analysis of risk factors revealed that advanced age, prolonged hospitalization, long duration of antibiotic intake, potentiated penicillins, 3 rd generation cephalosporins, antibiotic combined therapy, liver cirrhosis, malignancy, proton pump inhibitors, enteral tube feeding, and cancer chemotherapy were significantly associated with CDI. Sensitivitiy, specificitiy, positive predictive value, negative predictive value, and accuracy of real-time PCR against TC were all 100%, however, values of EIA were 79.4%, 100%, 100%, 94.3%, 95.3%, respectively. Conclusions: CDI is an underappreciated nosocomial infection predisposed by many risk factors. Real-time PCR proved superior diagnostic performance to toxin A/B EIA.