Clinical and microbial characterization of toxigenic Clostridium difficile isolated from antibiotic associated diarrhea in Egypt

Background and Objectives: Clostridium difficile infection (CDI) has become a significant healthcare-associated infection throughout the world and is particularly important in developing countries. This study aimed to investigate clinical characterization and risk factors related to toxigenic C. difficile infection in adult and pediatric patients, antimicrobial susceptibility pattern. Also, to evaluate different diagnostic methods for rapid detection of C. difficile associated diarrhea (CDAD) in Egypt. Materials and Methods: Stool samples were collected from 95 pediatric patients and 37 adult patients suffering from antibiotic associated diarrhea and were subjected to direct toxin immunoassay and culture on cycloserine/cefoxitin/fructose agar. The presence of tcdA and tcdB genes was tested by PCR. Results: Toxigenic C. difficile was isolated from pediatric and adult patients at a rate of 17.89% (17/95) and 27% (10/37) respectively. The sensitivity and specificity of direct PCR from stool are (100%, 100% and 82.4%, 100%) in adult and pediatric samples respectively. The susceptibility of C. difficile to vancomycin and metronidazole were found to be 66.7% and 48.2% respectively. Conclusion: Diabetes mellitus, prior antibiotic treatment, hematological malignancy on chemotherapy, malnutrition, neutropenia and Ryle feeding are risk factors for development of CDAD. Tight restriction of unnecessary antibiotic uses is necessary in our locality. Direct detection of toxin genes in stool by PCR is sensitive and specific method for early detection of C. difficile.

Detection of circulating antigens in patients with active Schistosoma haematobium infection

An antigen-capture ELISA using monoclonal antibody (MAb) 128C3/3/21 was used to detect circulating parasite-derived antigens in the sera of patients actively infected with Schistosoma haematobium (31 males and four females, 5-25 years of age). The assay had a sensitivity of 100% (35 of 35 patients with antigen levels > 80 ng/ml) and a specificity > 99%. We used this ELISA to monitor antigenemia before treatment and one, three, and six months after treatment with a single oral dose of praziquantel (PZQ) (60 mg/kg in 20 patients or 40 mg/kg in 15 patients) and compared our findings with those indicated by other measures of disease progression. Circulating antigen levels decreased drastically after PZQ treatment (P < 0.001), with a significantly higher decrease occurring after treatment with 60 mg/kg than with 40 mg/kg. Although the mean antigen level was still significantly reduced (P < 0.001) at six months after treatment, 16 patients remained antigen-positive after six months, and nine had increased levels of antigenemia, reflecting reinfection in six patients and persistence of infection in another. We observed a correlation (r = 0.6, P < 0.01) between the level of circulating antigen and the intensity of infection as measured by egg count. We also found a direct relationship (P < 0.001) between antigen level and the severity of the disease as monitored by ultrasonography. We conclude that our ELISA may be a useful adjunct to other methods, such as ultrasonography, for monitoring the course of S. haematobium infection and treatment.