Characterization and Prevalence of Escherichia coli and Klebsiella pneumoniae Isolates Producing an Extended-Spectrum beta-Lactamase from Korean Hospitals / 대한진단검사의학회지

BACKGROUND: The aim of this study was to survey the nationwide susceptibilities of E. coli and K. pneumoniae against third generation cephalosporins and aztreonam in order to determine the prevalence of extended-spectrum beta-lactamase (ESBL)-producers and to characterize genotypes of ESBLs. METHODS: A total of 6, 567 E. coli and 2, 652 K. pneumoniae non-duplicate strains were isolated from 13 hospitals in April to June 2002. Antimicrobial susceptibilities were tested by the disk diffusion method. Twenty isolates of E. coli and 20 K. pneumoniae were collected from each hospital. ESBL production was determined by a double-disk synergy test. The ceftazidime-resistance of the ESBL-producers was transferred to azide-resistant E. coli J53 by conjugation. MICs of beta-lactam antibiotics to transconjugants were determined by the agar dilution method. Searches for blaTEM , blaSHV , blaCTX-M and blaCMY genes in transconjugants were performed by PCR amplification. RESULTS: Eighty-nine percents of E. coli and 71% of K. pneumoniae isolates were susceptible to ceftazidime. Nine percents of E. coli (23/249) and 30% (78/260) of K. pneumoniae isolates showed positive results in the double-disk synergy test. Ceftazidime-resistance of 13 (57%) E. coli and 42 (53%) K. pneumoniae isolates were transferred to E. coli J53 by conjugation. Among 55 transconjugants, 46 strains were resistant to ceftazidime, while only 16 strains were resistant to cefotaxime. Twelve transconjugants were also resistant to cefoxitin and cefotetan. Banding patterns of PCR amplification showed that the blaTEM , blaSHV , blaCTX-M and blaCMY genes were harboured by 44, 39, 4 and 5 transconjugants, respectively. CONCLUSIONS: E. coli and K. pneumoniae isolates producing TEM-, SHV-type, or CTX-M-type ESBLs are wide spread in Korean hospitals. The spread of ESBL genes could compromise the future usefulness of 3rd generation cephalosporins and aztreonam for the treatment of E. coli and K. pneumoniae infections.

Diagnosis of Antibiotic-Associated Diarrhea and Pseudomembranous Colitis by Direct Detection of Clostridium difficile Toxin B Gene / 감염과화학요법

BACKGROUND: Clostridium difficile is the major cause of antibiotic-associated diarrhea (AAD) and pseudomembranous colitis (PMC). This study was designed to investigate predisposing factors of AAD or PMC and to evaluate the efficiency of nested PCR assay for direct detection of toxin B gene in the treatment and prognosis of these diseases. METHODS: From January to December, 2002, stool specimens from 142 patients in Kosin Medical Center, Busan, were tested for the detection of toxigenic C. difficile strains. Toxin B gene in C. difficile was detected by nested PCR. And chart review was performed to investigate the antibiotics or anticancer drug history, clinical symptoms, treatment regimens, and prognosis. RESULTS: Among 142 stool specimens, 56 specimens showed positive for the toxin B gene in C. difficile strains by PCR. Forty two percents (47/113) of stool specimens from patients with AAD and all of specimens from eight patiens with PMC were C. difficile toxin B gene positive. Administration of antibiotics or anticancer drugs was stopped in 92.7% of toxin B gene-positive cases, but those were stopped in only 48.5% of toxin B gene-negative cases. The cure rate was higher in positive cases (82%) than negative ones (71%). CONCLUSION: It is concluded that nested PCR assay for the direct detection of C. difficile toxin B gene was helpful in rapid diagnosis and treatment of AAD or PMC.

Diagnosis of Antibiotic-Associated Diarrhea and Pseudomembranous Colitis by Direct Detection of Clostridium difficile Toxin B Gene / 감염과화학요법

BACKGROUND: Clostridium difficile is the major cause of antibiotic-associated diarrhea (AAD) and pseudomembranous colitis (PMC). This study was designed to investigate predisposing factors of AAD or PMC and to evaluate the efficiency of nested PCR assay for direct detection of toxin B gene in the treatment and prognosis of these diseases. METHODS: From January to December, 2002, stool specimens from 142 patients in Kosin Medical Center, Busan, were tested for the detection of toxigenic C. difficile strains. Toxin B gene in C. difficile was detected by nested PCR. And chart review was performed to investigate the antibiotics or anticancer drug history, clinical symptoms, treatment regimens, and prognosis. RESULTS: Among 142 stool specimens, 56 specimens showed positive for the toxin B gene in C. difficile strains by PCR. Forty two percents (47/113) of stool specimens from patients with AAD and all of specimens from eight patiens with PMC were C. difficile toxin B gene positive. Administration of antibiotics or anticancer drugs was stopped in 92.7% of toxin B gene-positive cases, but those were stopped in only 48.5% of toxin B gene-negative cases. The cure rate was higher in positive cases (82%) than negative ones (71%). CONCLUSION: It is concluded that nested PCR assay for the direct detection of C. difficile toxin B gene was helpful in rapid diagnosis and treatment of AAD or PMC.

Clinical Significance of Colonoscopy in Patients with Benign Anorectal Disease

PURPOSE:Benign anorectal disease will often cause great concern to the patient and the practitioner about a more proximal colon pathology. The aim of this study is to evaluate the significance of routine colonoscopy for patients with benign anorectal disease. METHODS:A retrospective analysis of 108 patients with benign anorectal disease who had undergone colonoscopic examination from April 1997 to August 1998 at Gil Medical Center was done. RESULTS:The mean age of all patients was 43 years; the male-to-female ratio was 1:1.1. The diagnoses of anorectal disease were hemorrhoids in 84 cases, anal fissures in 13 cases, chronic anal pain syndrome in 6 cases, anorectal fistulas in 5 cases, and other in 9 cases. There were 37 patients (34.3%) with 53 abnormal findings:14 tubular adenomas, 11 inflammatory polyps, 4 hyperplastic polyps, 1 tuberculous colitis, 1 angiodysplasia, 6 diverticula, 6 nonspecific ileitis or colitis, 2 melanosis coli, 2 rectal ulcers, 2 ileal ulcers, and 3 other diseases. Among them, clinically significant lesions, such as neoplastic lesion, tuberculous colitis and angiodysplasia, were detected in 12 patients (11.1%). Because the lesions in 7 patients of the 12 patients were within the reach of sigmoidoscopy, only 5 patients (4.6%) needed a colonoscopic examination. In regard to neoplasms, patients presenting with anal bleeding and old age were not found to have a higher frequency of neoplasia. Also, the specific type of anorectal disease was not associated with an increased risk for colorectal neoplasia (P>0.05). CONCLUSIONS:Sigmoidoscopy is a more acceptable primary diagnostic tool in patients with benign anorectal disease, but in patients with gastrointestinal symptoms, a high risk for colorectal cancer, suspicious inflammatory bowel disease, or fear of cancer, selective colonoscopy will be needed.