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

doi:10.3390/microorganisms7120704

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® CarbaR + MCR, AusDiagnostics MT CRE EU, and EasyScreen™ ESBL/CPO. The prevalence of Klebsiella pneumoniae 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.

Highlights

Antimicrobial resistance is one of the most complex global health challenges [1]
The prevalence detected for Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae was around 2,2% (22/1015), while the detection of MBLs and OXA-48 was infrequent (NDM-1 = 2 samples, VIM = 1 sample, OXA-48 = 2 samples)
22 0 22 a A specimen was KPC-positive for routine screening, while with the Amplidiag kit, specimens were positive for KPC and VIM targets

Summary

Introduction

Antimicrobial resistance is one of the most complex global health challenges [1]. The World Health Organization puts the development of new antibacterial agents to treat carbapenem-resistant Enterobacteriaceae (CRE) among the most critical priorities [2]. Because CRE are resistant to the majority of β-lactams, carbapenem resistance has minimized the usefulness of many commercially available drugs [3]. CRE frequently carry mechanisms conferring resistance to other antimicrobial classes, further limiting the available therapeutic options [4,5,6]. Resistance to carbapenems is typically based on two main mechanisms. The first one is related to structural mutations combined with the activity of other β-lactamases, such as AmpC cephalosporinase (AmpC)

Methods

Results

Conclusion