357. Changes Observed in Diagnosis and Management of Clostridium difficile Infection (CDI) After Change from Enzyme Immunoassay (EIA) to Polymerase Chain Reaction (PCR) for Detection
Session: Poster Abstract Session: Clostridium difficile - Epidemiology, Diagnosis, Treatment, and Prevention
Friday, October 21, 2011
Room: Poster Hall B1
Background: Clostridium difficile infection (CDI) is a serious illness associated with considerable morbidity and mortality.  Use of a more sensitive laboratory testing method such as PCR may allow patients to be diagnosed earlier and more accurately, potentially leading to decreases in delay of diagnosis, disease relapse, unnecessary repeat testing, and unnecessary empiric treatment.

Methods: To compare diagnosis and management of CDI after change of detection method from EIA to PCR, we studied all adult patients tested and treated for CDI in a 4 month period where EIA was the exclusive test for detection of C. difficile toxin (CDT) and in the following 4 month period where PCR was the exclusive test for detection.

Results: (1) Both study groups were similar in age, gender, antibiotic exposure, previous hospitalization, acid suppression, and skilled nursing residence.  (2) In the baseline period, there were 164 patients with positive CDT results, derived from 1224 EIA tests submitted (13.4% positive).  Relapse cases represented 9% of the total.  Multiple tests for the same patient were frequent, with multiple tests required in 10% of patients to return a positive test.  48 patients received empiric treatment with oral vancomycin without a positive result.  (3) In the study period, there were 190 patients with positive CDT results, derived from 837 PCR tests (22.7% positive).  Relapse cases represented 9% of the total.  Multiple tests for the same patient were not permitted, and no multiple tests were submitted to establish a positive result.  38 patients received empiric treatment with oral vancomycin without a positive result.

Conclusion: As new and expensive treatment options become available, more accurate initial testing for CDT becomes imperative.  PCR appears to be more sensitive than EIA as the test method to detect CDT, detecting 16% more cases in a similar time period, with fewer tests ordered, a higher positivity rate, and multiple testing not permitted.  EIA failed to produce a positive test result initially in 10% of eventual positives, with multiple testing frequent.  Fewer patients were started on empiric treatment for CDI without documented positive toxin result when the testing method was changed to PCR.


Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Dale Lieu, MD1, Leia Skol, PharmD2, Teresa Corbala, PharmD2 and Bibiane De Rosales, PharmD2, (1)Kaiser Permanente Medical Program, Poway, CA, (2)Kaiser Permanente, San Diego, CA

Disclosures:

D. Lieu, None

L. Skol, None

T. Corbala, None

B. De Rosales, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.