This study first identified multidrug-resistant Staphylococcus haemolyticus ST42 strains carrying novel ΨSCCmec57395-like structures and type I aj1–LP–fusB resistance islands in Taiwan hospitals, revealing their potential as emerging opportunistic pathogens in healthcare settings. It provides critical insights into the evolution and transmission of antibiotic resistance mechanisms.
Literature Overview
This study, published in the journal Antibiotics, reviews the significance of Staphylococcus haemolyticus (S. haemolyticus) in hospital-associated infections and its multidrug-resistant characteristics. The research reveals the ΨSCCmec57395-like drug resistance structures and fusB-mediated resistance islands in S. haemolyticus strains in Taiwan hospitals, further highlighting its threat as an emerging nosocomial pathogen.
Background Knowledge
Staphylococcus haemolyticus is a common commensal bacterium that has recently become a significant pathogen in healthcare-associated infections, particularly among immunocompromised and burn patients. The strain exhibits resistance to multiple antibiotics (e.g., oxacillin, erythromycin, clindamycin, tetracycline, and fusidic acid), making treatment options extremely limited. Fusidic acid resistance is primarily mediated by fusB or fusC genes, with fusB being more prevalent and typically associated with low-level resistance. Additionally, the strain carries various heavy-metal resistance genes, such as cadD, cadX, arsC, arsB, arsR, and copA, which commonly coexist with mobile genetic elements (MGEs) to facilitate horizontal gene transfer. The study focuses on structural characteristics of SCCmec elements and fusidic acid resistance islands, particularly their molecular epidemiology and evolutionary dynamics in Taiwan hospitals, providing data support for subsequent resistance monitoring and transmission mechanism research.
Research Methods and Experiments
The research team collected 140 clinical S. haemolyticus isolates from 2010 to 2017 and performed MLST typing. Two representative strains (SH51 and SH53) were selected for whole-genome sequencing, and specific primers were used for PCR amplification and structural analysis of SCCmec elements and fusidic acid resistance islands. Resistance genes were identified using ResFinder and CARD databases, and structural variations of gene islands were analyzed via BLAST alignment with international reference genomes.
Key Conclusions and Perspectives
Research Significance and Prospects
This study reports the first identification of ΨSCCmec57395-like structures in clinical S. haemolyticus, suggesting their potential role as key MGEs in global resistance dissemination. Future efforts should prioritize longitudinal surveillance to track resistance element evolution and investigate co-selection mechanisms between heavy-metal and antibiotic resistance genes, enabling more effective infection control strategies.
Conclusion
This study demonstrates that S. haemolyticus ST42 has become the predominant multidrug-resistant clone in Taiwan hospitals. Its ΨSCCmec57395-like resistance elements and type I aj1–LP–fusB resistance islands may enhance adaptability through horizontal gene transfer. The research provides critical insights for resistance genomic structure analysis, nosocomial infection control, and pathogen evolutionary dynamics under antimicrobial selection pressure, underscoring the necessity for continuous monitoring. Additionally, it establishes a theoretical foundation for future studies in gene-edited animal models to investigate resistance gene regulatory networks and dissemination mechanisms.
