Abstract:
Objective: To evaluate the accuracy of the Rapidec® Carba NP test for early detection of carbapenemase-producing Klebsiella pneumoniae. Method: A total of 301 Klebsiella pneumoniae isolates were collected from 31 wards of both Departments of Medicine and Surgery in King Chulalongkorn Memorial Hospital. In-house conventional polymerase chain reaction (PCR) method, a gold standard method, and the Rapidec® Carba NP test were performed to detect carbapenemase-producers in all isolates. The accuracy of the Rapidec® Carba NP test, prevalence, risk factors, infection and colonization rates and mortality rate of CPK were evaluated. Results: Carbapenemase-producing Klebsiella pneumoniae (CPK) was found in 83/301 isolates, so the prevalence of CPK among K. pneumoniae was 28%. Most of CPK in our setting was documented to colonization (73.5%). The most common carbapenemase gene was blaOXA-48 in 71/83 isolates (85.5%), followed by blaNDM in 62/83 isolates (74.7%) but no presentation of blaKPC and blaVIM. The Rapidec® Carba NP test has a 95.2% sensitivity (95% CI, 88.1 to 98.7), a 99.5% specificity (95% CI, 97.5 to 100), a 98.8% positive predictive value (95% CI, 93.2 to 100), and a 98.2% negative predictive value (95% CI, 95.4 to 99.5). The significant risk factors for acquisition of CPK were cerebrovascular disease, malignancy and post-operation. Colistin and fosfomycin were common antibiotics for CPK infection (59.1% and 54.5%, respectively). In-hospital mortality rate among patients who had CPK infection was significant higher than CPK colonization (50% vs 24.6%, P = 0.03). Conclusion: In our study, the prevalence of carbapenemase-producing K. pneumoniae (CPK) is very high and associated with significant mortality. The Rapidec® Carba NP test has a very impressive sensitivity and specificity for early detection of carbapenemases in clinically significant K. pneumoniae. This promising diagnostic tool may contribute improving of infection control in hospital.