ABSTRACT
Background and Purpose: Clostridium difficile [C. difficile] is the most common cause of nosocomial acquired, antibiotic-associated diarrhea [AAD], that's called Clostridium difficile associated disease [CDAD]. This organism causes about 20% of the cases of AAD, up to 75% of the cases of antibiotic-associated colitis, and virtually all the cases of pseudomembranous colitis [PMC]
Patients and Methods: Sixty isolates were collected; all had been obtained from hospitalized patients under antibiotic therapy. Clostridium difficile associated diarrhea was defined as the presence of diarrhea >/=6 watery stools in a 36 hours period in a patient with a positive stool culture or a positive cytotoxin assay. Primary cultures were done on selective medium for C. difficile, cefoxitin-cycloserine fructose agar [CCFA]. C. difficile isolates were presumptively identified by their colony morphology. Additional biochemical tests were also used. API A TB 32A Rapid ID Anaerobe Identification Kit was also used for confirmation of the biological identification. Gas liquid chromatography [GLC] was used to detennine the volatile fatty acids produced by the growth of the organisms. Production of C. difficile toxin A [TcdA] is determined by the ToxA TEST immuno assay. The presence of C. difficile toxin B was determined by demonstrating a specific cytopathic effect on MRC-5 cells. Using HindIII restriction endonuclease did DNA extraction, PCR amplification and restriction endonuclease analysis. The pattern of each isolate was visually compared with the patterns of the previously identified REA groups in a well-characterized REA patterns library. Most patients were treated for respiratory tract infections [48% of cases] either lower [17 = 28%] or upper [12 = 20%]
Results: Patients treated by a combination of antibiotics formed 35% [25/60] of cases, 2 or 3 or 4 antibiotics. Cephalexin was associated with the highest incidence of CDAD [12=20%]. Clindamycin and amoxicillin formed 11 cases [= 18%]. The majority of COAD cases developed after 6-9 days use of antibiotics [45 patients = 75%]. Screening the isolates for sensitivity to metronidazole using E-test showed that, MIC50 [= 0.125 micro g/mL] and MIC90 [= 1 micro g/mL]. Only 2 isolates [= 3.033%] were inhibited at MIC = 16 micro g/mL and these isolates are identified as resistant strains [MIC >/=16 micro g/mL]
Conclusion: From this study we can ensure that CDAD is a serious problem caused by the use of broad-spectrum antibiotics for long periods especially in old age group of patients. Also we can conclude the high sensitivity of C. difficile to metronidazole; in spite of the recently emerging and rapidly expanding problem of resistance, which is still in need for further research work to be justified