Molecular Epidemiology of Staphylococcus aureus in a Tertiary Hospital in Anhui, China: ST59 Remains a Serious Threat

Huimin Zhang,1 Jiaxin Cao,1 Zhien He,2,3 Xianchun Zong,1 Baolin Sun2,3 1College of Life Science and Technology, Mudanjiang Normal University, Mudanjiang, People’s Republic of China; 2Department of Oncology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, People’s Republic of China; 3School of Life Science and Medicine, University of Science and Technology of China, Hefei, People’s Republic of ChinaCorrespondence: Baolin Sun, Email sunb@ustc.edu.cnPurpose: This study aimed to investigate the molecular characteristics, antimicrobial resistance and hemolytic phenotype of Staphylococcus aureus isolated from Anhui, China.Results: From August 2021 to January 2022, 214 S. aureus isolates were collected from the Anhui Provincial Hospital. This study identified 117 methicillin-resistant S. aureus and 97 methicillin-sensitive S. aureus isolates, and the detection rate of methicillin-resistant isolates was 1.8-fold higher than the average isolates reported in China (53.9% vs 30.5%). S. aureus isolates share identity at five or more of the seven MLST-based housekeeping loci, referred to as the clonal complex (CC). Forty ST types were found in 214 clinical S. aureus isolates, with the most extensive distribution of ST59 and ST6697 typing numbers and higher CC5 detection rates than any other clonal group. (The ST typing is the result of the MLST typing website query.) To detect the virulence of ST types of S. aureus, hemolysis experiments were performed on 214 clinical isolates, and it was concluded that ST59 had a relatively robust hemolytic capacity.Conclusion: Anhui S. aureus isolates have unique molecular and antibiotic resistance profiles. The antibiotic resistance profile may be related to the random use of antibiotics.Keywords: Staphylococcus aureus, epidemiological analysis, multilocus sequence typing, phenotype, hemolytic