Evaluation of the Hologic Panther Fusion MRSA Assay for the detection of MRSA in ESwab specimens obtained from nose, throat, and perineum

Recent updates in the development of molecular assays for the rapid identification and susceptibility testing of MRSA

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of healthcare- and community-associated infections. Nasal carriage of MRSA is a risk factor for subsequent MRSA infections. Increased morbidity and mortality are associated with MRSA infections and screening and diagnostic tests for MRSA play an important role in clinical management.

AREAS COVERED

A literature search was conducted in PubMed and supplemented by citation searching. In this article, we provide a comprehensive review of molecular-based methods for MRSA screening and diagnostic tests including individual nucleic acid detection assays, syndromic panels, and sequencing technologies with a focus on their analytical performance.

EXPERT OPINION

Molecular based-assays for the detection of MRSA have improved in terms of accuracy and availability. Rapid turnaround enables earlier contact isolation and decolonization for MRSA. The availability of syndromic panel tests that include MRSA as a target has expanded from positive blood cultures to pneumonia and osteoarticular infections. Sequencing technologies allow detailed characterizations of novel methicillin-resistance mechanisms that can be incorporated into future assays. Next generation sequencing is capable of diagnosing MRSA infections that cannot be identified by conventional methods and metagenomic next-generation sequencing (mNGS) assays will likely move closer to implementation as front-line diagnostics in the near future.

Evaluation of Methicillin-Resistant Staphylococcus aureus Carriage in the Elderly in Portugal Using Selective Enrichment Followed by quantitative real-time PCR

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals in Portugal is worrisome and among the highest in Europe. Surprisingly, MRSA prevalence in the community was described as very low (<2%) based on studies that used classical culture-based methods (CCBM). We investigated whether the apparent limited spread of MRSA in the community in Portugal might result from low sensitivity of CCBM. Nasopharyngeal- and oropharyngeal-paired samples obtained from senior adults living in nursing (n = 299) or family homes (n = 300) previously characterized by CCBM were reanalyzed. Samples were inoculated in a semi-selective enrichment medium, and those showing visible growth were evaluated by qPCR targeting nuc, mecA, and mecC genes (SSE+qPCR). By SSE+qPCR, 34 of the 1,198 (2.8%) samples were MRSA positive compared with 21 (1.8%) by CCBM. SSE+qPCR improved non-significantly detection of MRSA carriers from 5.4% to 8.0% (p = 0.12) in the nursing home collection, and from 0.3% to 1.7% (p = 0.13) in the family home collection. MRSA isolates belonged to three HA-MRSA clones widely disseminated in Portuguese hospitals. In conclusion, use of semi-selective medium combined with qPCR did not change the overall scenario previously described. In Portugal, MRSA circulation in the community among senior adults is low.