Prevalence and Molecular Epidemiology of Staphylococcus aureus among Residents of Seven Nursing Homes in Shanghai

Abstract

BackgroundResidents in nursing homes (NHs) always represent potential reservoirs for Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). To our knowledge, there is no epidemiological information up till now that describes the prevalence and molecular characteristics of S. aureus in nursing home residents in Shanghai, China.MethodsFour hundred and ninety-one unique residents from 7 NHs were enrolled in this study. Specimens were collected among these residents including 491 nasal swabs, 487 axillary swabs and 119 skin swabs. S. aureus isolated and identified from the swabs was characterized according to antimicrobial susceptibility profiling, toxin gene prevalence, and multilocus sequence typing (MLST), spa and SCCmec typing.ResultsAmong the 491 residents screened, S. aureus was isolated in 109 residents from 90 nasal swabs (90/491, 18.3%), 29 axillary swabs (29/487, 6.0%), and 22 skin swabs (22/119, 18.5%). Sixty-eight MRSA isolates were detected in 52 residents from 41 nasal carriers, 15 axillary carriers and 12 skin carriers. The overall prevalence rate of S. aureus and MRSA colonization was 22.2% and 10.6% respectively. Ten residents presented S. aureus in all three sample types and 12 residents presented S. aureus in two of the three sample types collected. Molecular analysis revealed CC1 (29.1%) to be the dominant clone in this study, followed by CC398 (19.9%), CC188 (13.5%) and CC5 (12.8%). The most common spa type was t127 (22.0%), followed by t14383 (12.8%) and t002 (10.6%).ConclusionsA high prevalence of S. aureus and MRSA colonization was revealed in nursing home residents in Shanghai. CC1 was the most common clonal complex and t127 was the most common spa type among NH residents. The data provides an important baseline for future surveillance of S. aureus in NHs in Shanghai and other highly urbanized regions in China. Implementation of infection control strategies must be given high priority in NHs to fight such high prevalence of both MRSA and methicillin-susceptible S. aureus (MSSA).

Molecular Diversity of Staphylococcus aureus Colonizing the Upper Respiratory Tract of Residents and Staff in A Nursing Home

“…S. aureus colonizes multiple anatomical locations and the frequency of colonization in various niches might vary depending on the methodology and the context of the study. Our study demonstrated that the anterior nares are colonized more frequently than the throat, which is consistent with the findings of previous studies on the prevalence of both MSSA and MRSA occurring together (Roghmann et al 2015;Zhang et al 2015;Peters et al 2017). Alternatively, some researchers have reported that colonization only in the throat is the most prevalent pattern (Nilsson and Ripa 2006;Hamdan-Partida et al 2010) or have observed the high prevalence of extra-nasal colonization as well, i.e., in the groin and the perianal regions (Mody et al 2008).…”

“…Staphylococcus aureus is an opportunistic human pathogen known for its increasing prevalence in both hospitals and the general community. An incremental rise in drug-resistance and high disease-causing capabilities has also been observed (Zhang et al 2015;Zurita et al 2016). The most common anatomical location for the commensal carriage of S. aureus is the anterior nares (Kluytmans et al 1997;Pollitt et al 2018), although recent epidemiological studies highlight the role of pharyngeal carriage in S. aureus transmission (Nilsson and Ripa 2006;Hamdan-Partida et al 2010).…”

Effectiveness of preoperative decolonization with nasal povidone iodine in Chinese patients undergoing elective orthopedic surgery: a prospective cross-sectional study

“…In our study, the prevalence of MRSA colonization was 1.28%, and the overall rate of S. aureus in the nasal region was 13.2%. Both of these rates were lower than the nasal carriage rates reported in other studies from China or abroad ( 1 , 9 , 18 – 22 ). MRSA incidence in elective orthopedic surgery was also lower than reported incidence in other surgeries ( 23 , 24 ).…”

“…Two methods commonly used for the identification of S. aureus include culturing and polymerase chain reaction (PCR). Culturing the bacteria on chromogenic agar is a less expensive test, while PCR is considered the ‘gold standard' for MRSA detection ( 15 – 17 ). Our decision to use the culture method was based on the economic standpoint (less expensive for the cost of material and labor) and the desired speed to provide the test result (1–2 days).…”

Molecular Epidemiology of Staphylococcus aureus among Patients with Skin and Soft Tissue Infections in Two Chinese Hospitals

“…Moreover, the TSST-1 ST5 has been described in China and France before. [ 22 23 ] Besides frequently discovered among SSTIs patients in China currently, ST7 was also found to be the most common genotype of MSSA in invasive community-acquired S. aureus infection in Chinese children. [ 24 ]…”