ASSESSMENT OF METRONIDAZOLE SUSCEPTIBILITY甲硝唑敏感性评价.doc

ASSESSMENT OF METRONIDAZOLE SUSCEPTIBILITY IN CLOSTRIDIUM DIFFICILE ISOLATES RECOVERED FROM CASES WITH ANTIBIOTIC DIARRHEAL DISEASES
 
By
Mahmoud Shokry Mahmoud, Hazem A. Rezk,
Wafaa K. M. Mahdi* and Enas Mamdouh Hefzy
Department of Microbiology and Immunology, El-Minia Faculty of Medicine
ABSTRACT:
Background and Purpose: Clostridium difficile (C. difficile) is the mon cause of ial acquired, antibiotic-associated diarrhea (AAD), that’s called Clostridium difficile associated disease (CDAD). anism 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 ATB 32A Rapid ID Anaerobe Identification Kit was also used for confirmation of the biological identification. Gas liquid chromatography (GLC) was used to determine the volatile fatty acids produced by the growth of anisms. 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 pared 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 lowe