Active Surveillance of Carbapenemase-Producing Organisms (CPO) Colonization With Xpert Carba-R Assay Plus Positive Patient Isolation Proves to Be Effective in CPO Containment

Abstract

Background: Rapid screening of patients for colonization with carbapenemase-producing organisms (CPO), coupled with implementation of infection prevention strategies, has the potential to contain the spread of CPO. Methods: We first evaluated the performance of Xpert Carba-R assay (in comparison with other phenotypic methods) for carbapenemase detection using clinical isolates, and then used it to determine the intestinal CPO colonization in hospitalized patients. We then assessed the effectiveness of patient isolation in controlling the spread of CPO in a medical intensive care unit. Results: The Xpert Carba-R assay required the least processing time to reveal results and showed a 94.5% sensitivity and specificity in carbapenemase detection, except for IMP-8 ( n = 4). During a 6-month study period, 134 patients in one ward were studied for CPO colonization and infection. Fifteen patients (11.2%) were colonized by CPO as detected by Xpert Carba-R assay, including three NDM, three IMP, and nine KPC possessing strains. The overall colonization and CPO infection rates were both 11.2% each. Isolation of patients with CPO led to a reduction in both colonization (from 28.6 to 5.6%) and infection rates (from 35.7 to 2.8%) during the study period ( p < 0.05). Conclusion: Active surveillance of CPO utilizing the Xpert Carba-R assay supplemented with immediate patient isolation, proved to be an effective strategy to limit the spread of CPO in a health care setting.

Evaluation of NG-Test Carba 5 for Rapid Phenotypic Detection and Differentiation of Five Common Carbapenemase Families: Results of a Multicenter Clinical Evaluation

“…The NG-Test Carba 5 assay was compared to a composite reference method. The composite reference method included (i) phenotypic detection of carbapenemase production by mCIM and (ii) molecular detection of carbapenemase genes by the U.S. FDA-cleared Xpert Carba-R real-time PCR assay (1,12,13,15,(17)(18)(19)(20)(21)(22). Table 1 summarizes how the NG-Test Carba 5 results were interpreted based on the results of the composite reference method prior to discrepant analysis.…”

Evaluation of Xpert Carba‐R Assay for the Detection of Carbapenemase Genes in Gram‐Negative Bacteria

“…Another limitation of Xpert Carba-R assay lies in that although Xpert Carba-R assay could effectively detect various types of samples, the samples must be cultured in advance [ 9 ]. At the same time, the decrease of the positive rate may also be due to the low bacterial load of the samples [ 12 ]. Moreover, different types of samples are always accompanied with varied sensitivities of the tests [ 21 ], which are the problems that await more advanced Xpert Carba-R assay to solve.…”

“…Another limitation of Xpert Carba-R assay lies in that although Xpert Carba-R assay could effectively detect various types of samples, the samples must be cultured in advance [9]. At the same time, the decrease of the positive rate may also be due to the low bacterial load of the samples [12].…”

“…Through the supplied pipette, the sample reagents were added to the Xpert Carba-R kit and analyzed by the Cepheid GeneXpert platform [ 10 , 11 ]. The result proves Xpert Carba-R analysis a reliable, accurate, and easy-to-use multiple qualitative analytic tool that is able to detect five clinically relevant carbapenemase gene families directly from the rectal swabs, which takes reduced time comparing with other culture-based methods for the identification of patients with gastrointestinal colonization of carbapenem-resistant organisms (CPO) [ 12 , 13 ]. The purpose of this study is to evaluate the performance of Xpert Carba-R assay in detecting carbapenemase genes in GNB, thereby providing a good epidemiological tool and a reference standard for clinical diagnosis.…”

Multicenter Evaluation of Xpert Carba-R Assay for Detection and Identification of the Carbapenemase Genes in Rectal Swabs and Clinical Isolates

“…Genotypic tests that can differentiate between isolates with serine-based b-lactamases versus metallo-b-lactamases can help to optimize antibiotic management, improve prognosis of infections, and even prevent the emergence of resistance. 37,38 Rapid detection of CPO during admission examination can aid infection control activities, such described in the study by Zhou et al, 39 which showed the value of Xpert Carba-R for containing the spread of CPO in critical care units. In addition, the excellent reproducibility of Xpert Carba-R was shown in the intra-assay and interassay studies with CV <2%.…”