Clinical microbiology costs for methods of active surveillance for Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae.

Objective: To compare direct laboratory costs of different methods for perirectal screening for carbapenemase-producing Enterobacteriaceae (CPE) colonization.

Design: Cost-benefit analysis.

Setting: A university hospital and affiliated long-term acute care hospital (LTACH).

Participants: Inpatients from the hospital or LTACH.

Methods: Perirectal samples were collected from inpatients at risk for exposure to CPE. In 2009, we compared the accuracy of the Centers for Disease Control and Prevention (CDC)-recommended CPE screening method with similar methods incorporating a chromogenic agar (CA). We then performed a cost projection analysis using 2012 screening results for the CA method, the CDC method, and a molecular assay with wholesale pricing based on the 2009 analysis. Comparisons of turnaround and personnel time were also performed.

Results: A total of 185 (2.7%) of 6,860 samples were confirmed as CPE positive during 2012. We previously found that the CDC protocol had a lower sensitivity than the CA method and predicted that the CDC protocol would have missed 92 of the CPE-positive screening results, whereas the modified protocol using CA would have missed 26, assuming similar prevalence and performance. Turnaround time was 3 days using the CDC and CA-modified protocols compared with 1 day for molecular testing. The estimated annual total program cost and total technologist's hours would be the following: CA-modified protocol, $37,441 and 376 hours; CDC protocol, $22,818 and 482 hours; and molecular testing, $224,596 and 343 hours.

Conclusions: The CDC screening protocol appeared to be the least expensive perirectal screening method. However, expense must be weighed against a lower sensitivity and extra labor needed for additional work-up of non-CPE isolates. The molecular test has the shortest turnaround time but the greatest expense.