We evaluated a three-step algorithm for laboratory diagnosis of Clostridium difficile-associated diarrhoea (CDAD). First, stool specimens were screened using an EIA test for glutamate dehydrogenase detection. Screen-positive specimens were tested by a rapid cytotoxintoxin A/B assay and subjected to stool culture. All cultures positive for C. difficile underwent toxigenic culture. The results showed that toxigenic culture allowed us to recover 37/156 (24.4%) stool samples harbouring toxigenic C. difficile that would have been missed by using faecal cytotoxin assay alone. This determined an increase ininfection prevalence of 4.2% (from 11.4% to 15.6 %). Furthermore, to characterize the clinical Clostridium difficile isolates and the distribution of PCR ribotypes circulating in the San Carlo Borromeo hospital, molecular typing using semi-automated repetitive-sequence-based PCR (rep- PCR) and PCR ribotyping, and an evaluation of the antibiotic resistance were also performed. Among them, 71 indistinguishable strains were detected by rep-PCR and 83 by PCR-ribotyping revealing C. difficile outbreaks in our hospital. A total of 6 different ribotypes were obtained by PCR ribotyping. The most frequent ribotype was 018 (88.2%) that also showed resistance to moxifloxacin. In one case, uncommon PCR ribotype 186 was also identified.
Laboratory diagnosis of Clostridium difficile associated diarrhoea and molecular characterization of clinical isolates / G. Russello, A. Russo, F. Sisto, M.M. Scaltrito, C. Farina. - In: NEW MICROBIOLOGICA. - ISSN 1121-7138. - 35:3(2012), pp. 301-310.
Laboratory diagnosis of Clostridium difficile associated diarrhoea and molecular characterization of clinical isolates
F. Sisto;M.M. ScaltritoPenultimo
;
2012
Abstract
We evaluated a three-step algorithm for laboratory diagnosis of Clostridium difficile-associated diarrhoea (CDAD). First, stool specimens were screened using an EIA test for glutamate dehydrogenase detection. Screen-positive specimens were tested by a rapid cytotoxintoxin A/B assay and subjected to stool culture. All cultures positive for C. difficile underwent toxigenic culture. The results showed that toxigenic culture allowed us to recover 37/156 (24.4%) stool samples harbouring toxigenic C. difficile that would have been missed by using faecal cytotoxin assay alone. This determined an increase ininfection prevalence of 4.2% (from 11.4% to 15.6 %). Furthermore, to characterize the clinical Clostridium difficile isolates and the distribution of PCR ribotypes circulating in the San Carlo Borromeo hospital, molecular typing using semi-automated repetitive-sequence-based PCR (rep- PCR) and PCR ribotyping, and an evaluation of the antibiotic resistance were also performed. Among them, 71 indistinguishable strains were detected by rep-PCR and 83 by PCR-ribotyping revealing C. difficile outbreaks in our hospital. A total of 6 different ribotypes were obtained by PCR ribotyping. The most frequent ribotype was 018 (88.2%) that also showed resistance to moxifloxacin. In one case, uncommon PCR ribotype 186 was also identified.Pubblicazioni consigliate
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