Comparison of Four Commercial Screening Assays for the Detection of blaKPC, blaNDM, blaIMP, blaVIM, and blaOXA48 in Rectal Secretion Collected by Swabs

Francesca Del Bianco, Manuela Morotti, Silvia Zannoli, Giorgio Dirani, Michela Fantini, Maria Federica Pedna, Patrizia Farabegoli, Vittorio Sambri

Microorganisms · 2019 · 16 citations · 18 references

DOIFull text

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Abstract

The spread of carbapenem-resistant Enterobacteriaceae (CRE) has been enabled by the lack of control measures directed at carriers of multidrug-resistant organisms in healthcare settings. Screening patients for asymptomatic colonization on the one hand, and implementation of contact precautions on the other hand, reduces patient-to-patient transmission. Screening plates represents a relatively low-cost method for isolating CRE from rectal swabs; however, molecular assays have become widely available. This study compared the performance of four commercial molecular platforms in detecting clinically significant carbapenemase genes versus routine screening for CRE. A total of 1015 non-duplicated rectal swabs were cultured on a chromogenic carbapenem-resistant selective medium. All growing Enterobacteriaceae strains were tested for carbapenemase-related genes. The same specimens were processed using the following molecular assays: Allplex™ Entero-DR, Amplidiag<sup>®</sup> CarbaR + MCR, AusDiagnostics MT CRE EU, and EasyScreen™ ESBL/CPO. The prevalence of <i>Klebsiella pneumoniae</i> carbapenemase (KPC)-producing Enterobacteriaceae detected by swab culture was 2.2%, while organisms producing oxacillinase (OXA)-48 and metallo-β-lactamases were infrequent. The cost of CRE-related infection control precautions, which must be kept in place while waiting for screening results, are significant, so the molecular tests could become cost-competitive, especially when the turnaround time is decreased dramatically. Molecular assays represent a powerful diagnostic tool as they allow the rapid detection of the most clinically relevant carbapenemases.

References

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