Air dispersal of meticillin-resistant Staphylococcus aureus in residential care homes for the elderly: implications for transmission during the COVID-19 pandemic.

BACKGROUND: Meticillin-resistant Staphylococcus aureus (MRSA) infections are rampant in hospitals and residential care homes for the elderly (RCHEs). AIM: To analyse the prevalence of MRSA colonization among residents and staff, and degree of environmental contamination and air dispersal of MRSA in RCHEs. METHODS: Epidemiological and genetic analysis by whole-genome sequencing (WGS) in 12 RCHEs in Hong Kong. FINDINGS: During the COVID-19 pandemic (from September to October 2021), 48.7% (380/781) of RCHE residents were found to harbour MRSA at any body site, and 8.5% (8/213) of staff were nasal MRSA carriers. Among 239 environmental samples, MRSA was found in 39.0% (16/41) of randomly selected resident rooms and 31.3% (62/198) of common areas. The common areas accessible by residents had significantly higher MRSA contamination rates than those that were not accessible by residents (37.2%, 46/121 vs. 22.1%, 17/177, P=0.028). Of 124 air samples, nine (7.3%) were MRSA-positive from four RCHEs. Air dispersal of MRSA was significantly associated with operating indoor fans in RCHEs (100%, 4/4 vs. 0%, 0/8, P=0.002). WGS of MRSA isolates collected from residents, staff and environmental and air samples showed that ST 1047 (CC1) lineage 1 constituted 43.1% (66/153) of all MRSA isolates. A distinctive predominant genetic lineage of MRSA in each RCHE was observed, suggestive of intra-RCHE transmission rather than clonal acquisition from the catchment hospital. CONCLUSION: MRSA control in RCHEs is no less important than in hospitals. Air dispersal of MRSA may be an important mechanism of dissemination in RCHEs with operating indoor fans.

First report of chronic implant-related septic arthritis and osteomyelitis due to Kytococcus schroeteri and a review of human K. schroeteri infections.

We report the first case of Kytococcus schroeteri implant-related septic arthritis and osteomyelitis, identified by phenotypic tests and 16S rRNA sequencing, which responded to implant removal and doxycycline. 16S rRNA sequencing was useful for the accurate and rapid identification of the organism as it exhibited three different colonial morphologies in vitro.

Primary infective spondylodiscitis caused by Lactococcus garvieae and a review of human L. garvieae infections.

We report the first case of primary infective spondylodiscitis due to Lactococcus garvieae, confirmed by 16S rRNA gene sequencing, in the absence of concomitant endocarditis in a patient with long-standing gastritis on famotidine. He responded to a 6-week course of ampicillin. The gastrointestinal tract is probably the source of infection.