A comparative genomic analysis between methicillin-resistant Staphylococcus aureus strains of hospital acquired and community infections in Yunnan province of China

Abstract

Background: Currently, Staphylococcus aureus is one of the most important pathogens worldwide, especially for methicillin-resistant S. aureus (MRSA) infection. However, few reports referred to patients' MRSA infections in Yunnan province, southwest China. Methods: In this study, we selected representative MRSA strains from patients' systemic surveillance in Yunnan province of China, performed the genomic sequencing and compared their features, together with some food derived strains. Results: Among sixty selective isolates, forty strains were isolated from patients, and twenty isolated from food. Among the patients' strains, sixteen were recognized as community-acquired (CA), compared with 24 for hospitalacquired (HA). ST6-t701, ST59-t437 and ST239-t030 were the three major genotype profiles. ST6-t701 was predominated in food strains, while ST59-t437 and ST239-t030 were the primary clones in patients. The clinical features between CA and HA-MRSA of patients were statistical different. Compared the antibiotic resistant results between patients and food indicated that higher antibiotic resistant rates were found in patients' strains. Totally, the average genome sizes of 60 isolates were 2.79 ± 0.05 Mbp, with GC content 33% and 84.50 ± 0.20% of coding rate. The core genomes of these isolates were 1593 genes. Phylogenetic analysis based on pan-genome and SNP of strains showed that five clustering groups were generated. Clustering ST239-t030 contained all the HA-MRSA cases in this study; clustering ST6-t701 referred to food and CA-MRSA infections in community; clustering ST59-t437 showed the heterogeneity for provoking different clinical diseases in both community and hospital. Phylogenetic tree, incorporating 24 isolates from different regions, indicated ST239-t030 strains in this study were more closely related to T0131 isolate from Tianjin, China, belonged to 'Turkish clade' from Eastern Europe; two groups of ST59-t437 clones of MRSA in Yunnan province were generated, belonged to the 'Asian-Pacific' clone (AP) and 'Taiwan' clone (TW) respectively. Conclusions: ST239-t030, ST59-t437 and ST6-t701 were the three major MRSA clones in Yunnan province of China. ST239-t030 clonal Yunnan isolates demonstrated the local endemic of clone establishment for a number of years, whereas ST59-t437 strains revealed the multi-origins of this clone. In general, genomic study on epidemic clones of MRSA in southwest China provided the features and evolution of this pathogen.

Comparison of virulence-related determinants between the ST59-t437 and ST239-t030 genotypes of methicillin-resistant Staphylococcus aureus

“…In their study, they concluded that the TW clone showed higher virulence in both humans and animal infection models, and they considered the acquisition of PVL, including other virulence factors that contributed to its enhanced pathogenic ability compared with the AP clone. Our previous study [ 10 ] verified that two subclones of the ST59 genotype of MRSA were prevalent in Southwest China, similar to Taiwan. In this study, both subclones of ST59-t437 isolates were used to compare their pathogenic abilities.…”

“…Our previous study revealed that ST59-t437 and ST239-t030 were the major genotype profiles of MRSA for human infections in Southwest China [ 10 ]. The ST239-t030 strain belonged to the HA-MRSA clone, while ST59-t437 showed heterogeneity in provoking different clinical diseases in the community.…”

“…Some virulence determinants are related to certain clonal types; therefore, it is important to analyse the phenotypic or pathogenic ability of specific clones of MRSA. In this study, we selected typical ST239-t030 (HA-MRSA) and ST59-t437 genotype isolates (CA-MRSA) from our previous research [ 10 ] and compared the phenotypic and pathogenic abilities among these strains both in vitro and in vivo.…”

Two-component signaling pathways modulate drug resistance of

“…These peptides are released into the cytoplasm with the assistance of the ATP-binding cassette (ABC) transport system (31). In addition to releasing its own bacteriocin, the ATP transport system also pumps exogenous bacteriocins out of the cytoplasm as a defense mechanism (32). Multiple ATP gene loci adjacent to the bicomponent signal were identified following the analysis of the gene locus of S. aureus (32).…”

“…In addition to releasing its own bacteriocin, the ATP transport system also pumps exogenous bacteriocins out of the cytoplasm as a defense mechanism (32). Multiple ATP gene loci adjacent to the bicomponent signal were identified following the analysis of the gene locus of S. aureus (32). However, S. aureus has not been confirmed to possess bacteriocin synthesis-associated genes, and therefore these structural sites are hypothesized to be primarily associated with immune defense (33).…”