Genomic epidemiology and characterization of methicillin-resistant staphylococcus aureus from bloodstream infections in China

• Main Authors: Chen, Y. (Author), Jin, Y. (Author), Luo, Q. (Author), Shen, P. (Author), Xiao, Y. (Author), Zhan, Q. (Author), Zheng, B. (Author), Zhou, W. (Author)
• Format: Article
• Language: English
• Published: American Society for Microbiology 2021
• Subjects: allele; amikacin; amikacin resistance; antibacterial activity; antibiotic resistance; antibiotic sensitivity; Article; bacterial evolution; bacterial gene; bacterial genome; bacterial strain; bacterial transmission; bacterial virulence; bacterium identification; bacterium isolate; beta-lactam resistance; bloodstream infection; bovine mastitis; chp gene; chromosome mutation; clonal evolution; community acquired infection; controlled study; cotrimoxazole; daptomycin; enterotoxin; Epidemiology; erythromycin; erythromycin resistance; erythromycin resistance gene A; erythromycin resistance gene B; erythromycin resistance gene C; Evolution; fluoroquinolone resistance; fosfomycin; gene cassette; gene insertion; gene mutation; genetic association; genetic distance; genome analysis; genomic island; Genomics; geographic distribution; grlA gene; horizontal gene transfer; hospital infection; levofloxacin; lincosamide; linezolid; methicillin resistant Staphylococcus aureus; microbial diversity; molecular epidemiology; molecular typing; moxifloxacin; MRSA; nonhuman; oxacillin; penicillin derivative; Phylogenetic reconstruction; phylogenetic tree; phylogeny; prevalence; qacA gene; rifampicin; rifampicin resistance; scn gene; single nucleotide polymorphism; species diversity; species dominance; Staphylococcus enterotoxin A; staphylokinase; superantigen; teicoplanin; tetracycline; tetracycline resistance; tigecycline; vancomycin; whole genome sequencing
• Online Access: View Fulltext in Publisher

 Since 2010, methicillin-resistant Staphylococcus aureus (MRSA) ST59 began to increase in prevalence in China, gradually replacing ST239 and has become the dominant clone in most hospitals in China. Here, we investigated the changing epidemiology, phylogenetic reconstruction, and genomic characterization of MRSA clones in China to identify the genomic driving factors in the prevalence of ST59. Most MRSA isolates were identified as ST59 (36.98%; 277/749), which increased from 25.09% in 2014 to 35.53% in 2019. The phylogenetic analysis of the 749 MRSA isolates showed a high level of diversity and the copresence of hospital-associated, community-associated, livestock-associated, and hypervirulent clones. Furthermore, minimum spanning trees revealed that ST59 MRSA clones from different hospitals and regions were integrated, suggesting that frequent exchanges had occurred between regions and hospitals. ST59 clones displayed higher susceptibility to antimicrobials than did ST239 and ST5 MRSA clones, indicating that resistance to non-b-lactam and fluoroquinolone antibiotics may be not critical for the epidemic success of ST59 clones. Virulence factors detection showed that sak and chp genes enriched in MRSA ST59 may be associated with the enhanced spreading success of ST59, whereas qacA may have contributed to the predominance of ST5 in East China. Our refined analysis of different clones among ST239, ST5, ST59, and ST398 demonstrated the existence of potential driving factors for the evolution of nosocomial MRSA populations and diversity of the evolutionary events surrounding clonal replacement. IMPORTANCE As a developing country, China has an unbalanced health care system due to regional differences in economic development. However, China is also a country worthy of study with regard to the population dynamics of MRSA within the more resource-rich health care systems. In this study, we carried out genomic analysis to investigate the genomic epidemiology and characterization of MRSA isolated from bloodstream infections over a timespan of 6 years. Our refined analysis of different MRSA clones among ST59, ST5, ST239, and ST398 demonstrated the existence of driving factors for the evolution of nosocomial MRSA populations and diversity of the evolutionary events surrounding clonal replacement. Copyright © 2021 Jin et al.