Work

Genomic and clinical characteristics of Staphylococcus aureus isolates associated with orthopedic infections from a rural hospital, Qingdao, China

Year: 2026

Type: article

Abstract: ABSTRACT Staphylococcus aureus is a leading pathogen associated with orthopedic infections, particularly in resource-limited settings where clinical management is complicated by antimicrobial resistance. To characterize the phenotypic and genomic features of S. aureus associated with orthopedic infections in rural China, 80 isolates were recovered from inpatients at a regional hospital in Qingdao. Clinical and demographic data were integrated with colony morphology, hemolysis, antimicrobial susceptibility testing, and whole-genome sequencing. Significant clinical differences were observed between community- and hospital-acquired infections in hospitalization duration, admission diagnosis, injury cause/site, and surgical intervention. The isolates represented 23 sequence types, with ST22, ST59, and ST25 being the most prevalent. Four novel STs (ST8153, ST8154, ST9407, ST9408) were identified. They were further characterized as 19 MRSA and 61 MSSA strains. 68.8% of isolates formed whitish colonies, while all were catalase-positive. 62.5% of isolates were multidrug-resistant, showing high resistance to penicillin (88.8%), erythromycin (63.8%), and clindamycin (62.5%), but all remained susceptible to vancomycin and linezolid. Comparative genomic analysis revealed diverse profiles of antimicrobial resistance genes, virulence factors, and mobile genetic elements, whose distributions were closely associated with sequence types. Phylogenetic comparison with 515 publicly available genomes highlighted clustering of local isolates with international lineages, underscoring both global dissemination and local evolution. This study expands current knowledge on the epidemiology, resistance, and genomic diversity of S. aureus in orthopedic infections, identifies novel STs, and provides evidence to improve surveillance and treatment strategies in rural healthcare settings. IMPORTANCE Orthopedic infections caused by Staphylococcus aureus remain a major clinical and public health concern, especially in rural regions where diagnostic and therapeutic capacities are limited. This study represents one of the first integrated clinical-genomic analyses of S. aureus from orthopedic infections in rural China. By combining patient-level data with phenotypic and genomic characterization, we reveal high rates of multidrug resistance, heterogeneous virulence and resistance gene profiles, and the emergence of novel sequence types. Comparative phylogenetic analyses demonstrate strong genetic links between rural Chinese isolates and globally disseminated lineages, emphasizing the international movement of epidemic clones. Together with antibiotic treatment data, these findings underscore the need for rational antimicrobial use, infection control, and continuous genomic surveillance. The discovery of novel lineages highlights ongoing local evolution of S. aureus and supports the importance of integrating genomics into orthopedic infection management and antimicrobial resistance mitigation in resource-limited settings.

Source: Microbiology Spectrum

DOI: 10.1128/spectrum.03692-25