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


METHODS
Four 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.


RESULTS
Among 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%).


CONCLUSIONS
A 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).
Department of Clinical Laboratory, Shanghai People's Hospital of Putuo District, Shanghai, China.
Ji
J
Zhang
Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Fei-Fei
FF
Gu
Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Sheng-Yuan
SY
Zhao
Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Shu-Zhen
SZ
Xiao
Department of Microbiology and Parasitology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Yan-Chun
YC
Wang
Department of Microbiology and Parasitology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Xiao-Kui
XK
Guo
Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Yu-Xing
YX
Ni
Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Li-Zhong
LZ
Han
D000368:Aged; D000369:Aged, 80 and over; D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002681:China / Q000453:epidemiology; D002947:Cities; D005260:Female; D005798:Genes, Bacterial; D005838:Genotype; D006707:Homes for the Aged; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D009296:Nasal Cavity / Q000382:microbiology; D009735:Nursing Homes; D015995:Prevalence; D012867:Skin / Q000382:microbiology; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology
D001427:Bacterial Toxins