Rectal Screening for Klebsiella pneumoniae Carbapenemases: Comparison of Real-Time PCR and Culture Using Two Selective Screening Agar Plates

Abstract

Klebsiella pneumoniae carbapenemases (KPCs) have recently been described in Chicago, IL, especially among residents of longterm acute care hospitals (LTACHs). These patients are frequently transferred to local Chicago hospitals for higher acuity of medical care, and rapid detection and isolation of KPC-colonized LTACH residents may interrupt the introduction of KPCs into acute care hospitals. We evaluated the performance of a real-time PCR for bla KPC from enrichment broth versus direct plating of rectal surveillance swabs on two selective culture media, CHROMagar extended-spectrum-␤-lactamase (ESBL) and vancomycin, amphotericin B, ceftazidime, and clindamycin (VACC) plates. Rectal surveillance swabs were collected as part of a point prevalence study of KPC carriage rates among 95 residents of two Chicago area LTACHs. Discrepant results between PCR and culture were resolved by subculturing the enrichment broth. Overall, 66 of 95 patients (69.5%) were colonized with KPCs, using the cumulative results of culture as a reference standard. Real-time PCR from enrichment broth was positive in 64 of 66 (97%) colonized patients, including nine surveillance swabs that were missed by both selective culture media. PCR demonstrated higher sensitivity, 97.0%, than culture using either CHROMagar or VACC plates (both with sensitivity of 77.3%). In addition, turnaround time was significantly shorter for the PCR-based method than for culture, with a mean of 24 h versus 64 to 72 h for CHROMagar and VACC plates (P < 0.0001). Overall, PCR for bla KPC represents the best screening test for KPCs with significantly higher sensitivity and with less hands-on time, resulting in a shorter time to results.

Sensitivity of Surveillance Testing for Multidrug-Resistant Gram-Negative Bacteria in the Intensive Care Unit

“…Furthermore, MDR GNB were identified phenotypically. This precludes definite conclusions about surveillance test sensitivity for organisms with specific mechanisms of resistance (e.g., specific carbapenemases) (2). Another limitation is that our data are based on culture testing.…”

Analytical Performance of Multiplexed Screening Test for 10 Antibiotic Resistance Genes from Perianal Swab Samples

“…Associated annual direct health care costs exceed $20 billion in the US (1 ). Gramnegative MDROs are especially worrisome, according to the Centers for Disease Control and Prevention (CDC), which reports that carbapenemase-resistant Enterobacteriaceae (CRE) have been found in medical facilities in 47 of the 50 states, with major outbreaks occurring in the Northeast, Chicago, and Denver (2 ).…”

“…Multidrug resistant organisms (MDROs) 2 are a growing concern globally. Every year, Ͼ2 million Americans are infected with antibiotic-resistant bacteria, resulting in 23 000 deaths because of a lack of therapeutic options to combat these bacteria (1 ).…”

Evaluation of the HB&L carbapenemase and extended spectrum beta lactamase-AmpC automated screening kits for the rapid detection of resistant Enterobacteriaceae in rectal swabs

“…Therefore the implementation of a reliable, rapid and sensitive screening test for the rapid identification of subjects that are rectal carriers of resistant bacteria among hospitalized patients is essential for the success of the infection control measures in a timely manner before they transmission occurs (e.g. assignment of colonized or infected patients to a single room and the use of disposable gown and gloves for all the personnel that are in contact with these patient) (1,6).…”