Clostridium difficile infection in ICU patients

Introduction

Clostridium difficile infection is becoming more common worldwide. Critically ill patients are at particularly high risk for this disease due to multiple risk factors in this population. Accurate diagnosis is essential for patient management, infection control and epidemiology. There are a variety of methods to detect the presence of toxigenic C. difficile in stools [1],[2]. The aim of this study was to evaluate the incidence of C. difficile infection in our ICU. Laboratory results of C. difficile toxin detection performed by the methods available in our institution are presented.

Methods

During the last year, all stool specimens received in the microbiology department from patients hospitalized in the 30-bed, multidisciplinary ICU of a tertiary-care hospital were evaluated. Specimens were ordered by physicians in the presence of clinical features compatible with C. difficile-associated infection. Each specimen was subjected to diagnostic tests for C. difficile infection including toxin enzyme immunoassays for C. difficile toxins A and B detection (DUO Toxin A&B; VEDA.LAB, France), and glutamate dehydrogenase (GDH) for cell wall antigen detection (C. DIFF Quik Chek Complete^®; USA).

Results

During the study period, 335 stool specimens were evaluated. Results obtained with the two-stage immunoassay tests are shown in Figure 1. All infected patients were treated with metronidazole or vancomycin. Following a course of therapy, 2% of the infected patients had recurrence or relapse. The crude mortality rate was 17%.

Figure 1

Illustration of the tests performed for detection of C. difficile.

Conclusion

GDH antigen was positive in 12% of the stool specimens received from ICU patients with suspected C. difficile -associated infections. The majority of these specimens (51.4%) produce both C. difficile toxins A and B, whereas toxin B is produced in 31.4% and toxin A in the remaining 17.2%.