Advanced Diagnostic Strategies for Clostridium difficile Infection (CDI)

Clostridium difficile infection (CDI) is a leading cause of nosocomial intestinal diseases and produces considerable morbidity and mortality among inpatients globally. The increasing incidence of CDI, especially of its severe cases, creates a growing financial burden internationally. The pathogen responsible for CDI, C. difficile, is an anaerobic, spore-bearing Gram-positive bacillus that colonizes gastrointestinal tract in humans and animals. The bacterium can transfer from one host to another via the oral-fecal route and is consequently a public health concern in the community as well as hospitals. CDI also has implications for the personal hygiene of patients and medical workers. Classical risk factors for CDI include old age, long inpatient stay, and use of antibacterial agents. Clinical manifestations and a positive laboratory assay are both needed for an accurate diagnosis of CDI. Laboratory testing for C. difficile should distinguish between toxigenic and non-toxigenic strains, as well as asymptomatic colonization and the clinical manifestations of infection. Most stand-alone assays do not attain the desired sensitivity and specificity, and thus multistep algorithms and automated assays have emerged in recent years. Hospitals have adopted various assays, combining their conjunct advantages to enable rapid results, accurate diagnosis, and decreased expenditure. This strategy ultimately prevents misdiagnosis and over-diagnosis simultaneously. In this review, we describe common strategies for diagnosis of CDI and compare commercially available multistep and automatic assays.