Pre-analytical and post-analytical evaluation in the era of molecular diagnosis of sexually transmitted diseases: cellularity control and internal control

<p><em>Background.</em> A national project on <em>Clostridium difficile</em> infection (CDI), funded by the Center for Prevention and Control of Diseases of Italian Ministry of Health, was performed in 2012-2013. Microbiological laboratories of the National Public Heath System were invited by the Istituto Superiore di Sanità to provide information on CDI diagnostics through a closed answer questionnaire. <br /><em>Materials and Methods.</em> In total, 14 regions and the independent province of Trento participated in and 278 filled questionnaires were sent back. The data obtained indicate that 87% of the laboratories routinely perform diagnostic assays for <em>C. difficile</em>. GDH detection is used as the first screening test by 33% of these laboratories. Most of them declared to use toxins enzyme immunoassays (88%), whereas a minority performs <em>C. difficile</em> culture (26%) or molecular assays (19%). Only 37% of the laboratories stated to adopt a diagnostic algorithm. The algorithms adopted are different and high heterogeneity in the combination of the assays used was observed. <br /><em>Results</em>. Fifty eight percent of laboratories declared to type <em>C. difficil</em>e strains, the majority (82%) sending faecal samples or strains to a reference laboratory. Sixty-two laboratories, routinely performing <em>C. difficile</em> culture, were invited by ISS to send five isolates for molecular typing. In total, 103 isolates from 22 hospitals were collected and 31 different PCR-ribotypes were identified. PCR-ribotype 356/607 was the most frequent (27%), followed by 018 (12%) and 027 (8%). The latter is a worldwide spread hypervirulent type only recently emerged in our country. A molecular characterization of the different PCR-ribotypes detected was also performed by Xpert® <em>C</em>. <em>difficile</em>. <br /><em>Conclusions</em>. The study highlights the need for a more careful selection of diagnostic algorithms to improve CDI diagnosis and the urgency to implement a National Surveillance of CDI in Italy.</p>

Abstract licence: CC BY-NC

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