Household Transmission of Community-Associated Methicillin-Resistant Staphylococcus Aureus.

Feiteng Zhu,Shujuan Ji,Lingfang Di,Haiping Wang,Zhengan Wang,Hemu Zhuang,Shengnan Jiang,Lu Sun,Ping Shen,Er Xu,Yan Chen,Yunsong Yu

doi:10.3389/fpubh.2021.658638

Abstract

Currently, the mechanism of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) transmission mechanism is unclear; however, it must be considered in conjunction with asymptomatic S. aureus strains colonization dynamics. This epidemiological study aimed to determine the role of the household in CA-MRSA transmission in China. Five patients with culture-confirmed CA-MRSA infection and five control patients were recruited from the Sir Run Run Shaw Hospital in Zhejiang, China, between December 2019 and January 2020. The household members of the patients, their pets, and environmental surfaces were sampled and screened for MRSA colonization. Mass spectrometry identification and antimicrobial susceptibility testing were performed on the MRSA isolates. Whole-genome sequencing and core genome multilocus sequence typing (cgMLST) were performed to determine the origin and transmission of the MRSA isolates in the households. Overall, 14 S. aureus-positive specimens (14.1%, 14/99) were obtained from the five households of patients with CA-MRSA infections, of which 12 (85.7%) were MRSA. The overall positivity of MRSA was 12.1% (12/99) among the samples from the CA-MRSA households, while no MRSA isolates were detected in the five control households. Most MRSA isolates belonged to epidemic CA-MRSA clones, such as ST59 (15/35, 42.9%) and ST508 (15/35, 42.9%). The cgMLST results confirmed that MRSA was transmitted among patients, contacts, and pets in the households and was present on environmental surfaces in the CA-MRSA patients' households. In conclusion, the study revealed that the home environment was an important MRSA reservoir. Therefore, focusing on MRSA decolonization in patients alone is not sufficient for infection control of CA-MRSA.

Highlights

Staphylococcus aureus is the main cause of infections in hospitals and communities and contributes significantly to the healthcare burden (1)
We found that half of the methicillin-resistant S. aureus (MRSA) isolates were predominantly CAMRSA clones, including ST59 and ST72 (14)
In another study by Shahbazian et al, which included 95 homes of patients diagnosed with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection, MRSA was recovered from 68% (65/95) of the homes at baseline (18)

Summary

Introduction

Staphylococcus aureus is the main cause of infections in hospitals and communities and contributes significantly to the healthcare burden (1). Since the mid-1990s, an increase in methicillin-resistant S. aureus (MRSA) infections has been reported among populations without exposure risk within the healthcare system, caused by community-associated MRSA (CA-MRSA) strains (2). The CA-MRSA dissemination and transmission mechanisms remain unclear. Studies of CA-MRSA among family contacts of patients with CA-MRSA infection have found MRSA colonization rates of 8.7–37% (4). Unrecognized colonization of household contacts and contamination of the home environment may maintain colonization among individuals with MRSA. Methicillin-sensitive S. aureus (MSSA) and MRSA have been recovered from environmental samples collected in homes in which none of the inhabitants had signs of apparent infection (7, 8). The specific transmission mechanism of CA-MRSA is unclear (9)

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