Reducing rates of Clostridium difficile infection by switching to a stand-alone NAAT with clear sampling criteria

E Casari,C De Luca,M Calabrò,C Daleno,A Ferrario,C Scuderi

doi:10.1186/s13756-018-0332-2

Abstract

BackgroundClostridium difficile infection is an important cause of morbidity and mortality but the optimal method of diagnosis for both patient management and infection prevention remains controversial.MethodsOur hospital made a decision to switch from the use of toxin immunoassay to a stand-alone nucleic acid test. This change was accompanied by the provision of clear sampling guidance and rejection criteria and this study aimed to assess the impact of that change. We analysed sample numbers, numbers of positive results, and the proportion of cases assessed as healthcare acquired over a 6-year period during which the testing method was changed from a toxin A/B immunoassay to a stand-alone commercial nucleic acid test after the first two years.ResultsSample numbers and numbers of cases assessed as healthcare acquired fell following the introduction of the nucleic acid test and sampling guidance, while infection rates in other hospitals in the same region remained relatively stable.ConclusionsIt is our opinion that the use of a highly sensitive assay together with clear sampling guidance offers the optimal approach to patient management and best use of isolation facilities.

Highlights

Clostridium difficile infection (CDI) continues to cause significant morbidity, mortality, and increased hospital length of stay [1] but the optimal method of diagnosis remains controversial
Nucleic acid amplification tests (NAATs) detecting tcdB genes are highly sensitive for toxigenic Cdifficile strains, and assays such as the Cepheid XpertC difficile PCR test provide results in under an hour
During the first 2 years, all samples were tested with a toxin A/B enzyme immunoassay (TOXA/B QUIK CHEK, Techlab, Blaksburg, VA) and in the following four years testing was by a commercial NAAT assay (XpertC difficile, Cepheid, Sunnyvale, CA) as a standalone test

Summary

Introduction

Clostridium difficile infection (CDI) continues to cause significant morbidity, mortality, and increased hospital length of stay [1] but the optimal method of diagnosis remains controversial. In 2012, after many years of using toxin immunoassays, our hospital decided to introduce a commercial NAAT as a stand-alone test for the diagnosis of CDI, with clear guidance and rejection criteria for submission of samples. This retrospective analysis shows the impact of this strategy, based on rapid results, greater sensitivity of the assay, and shortened time to initiation of isolation of positive cases, on CDI rates. Clostridium difficile infection is an important cause of morbidity and mortality but the optimal method of diagnosis for both patient management and infection prevention remains controversial

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