Phenotypic and molecular epidemiological characteristics of foodborne methicillin-resistant Staphylococcus aureus
- Author:
WANG Jun
;
MA Xinxin
;
CHEN Xiaocao
- Publication Type:Journal Article
- From:
China Tropical Medicine
2024;24(11):1349-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the drug resistance, virulence, biofilm formation ability, and molecular epidemiological characteristics of foodborne methicillin-resistant Staphylococcus aureus (MRSA), and to provide data support for risk assessment of foodborne pathogens. Methods Antimicrobial susceptibility test, pulsed-field gel electrophoresis (PFGE) analysis, MLST, spa, SCCmec typing, biofilm formation ability determination, and virulence determination of Galleria mellonella were performed on 21 strains of foodborne MRSA isolated from commercially available food in Shaanxi Province from 2019 to 2020; The drug resistance genes, virulence genes, plasmids, and mobile genetic elements of the strains were analyzed by whole-genome sequencing. SNP and cgMLST were utilized to analyze the phylogenetic patterns of the isolates. Results The detection rate of 21 foodborne MRSA strains was highest in raw meat and meat products (80.95%, 17/21). The isolates were resistant to antibiotics such as penicillin, oxacillin, erythromycin, clindamycin, and tetracycline. PFGE typing showed 7 clusters with the band patterns being dispersed. There were 7 ST types, with ST59 being the main type (57.14%, 12/21); 6 spa types, with t437 as the main type (66.67%, 14/21); and 3 SCCmec types, with Ⅳa(2B) as the main type (71.43%, 15/21). Biofilm formation ability varied in 38.09% (8/21) of the strains. The MRSA isolate No.110 showed the highest toxicity, achieving a 100.00% mortality rate in Galleria mellonella larvae at a bacterial concentration of 1×106 CFU/mL within 36 hours. The results of whole-genome sequencing analysis showed that the strains carried 4-12 resistance genes, including β-lactam, aminoglycosides, macrolides, and tetracycline resistance genes, with 2 strains carrying the quaternary ammonium compound resistance gene qacG. All strains contained the autolysin gene aur and hemolysin genes hlgA, hlgB, and hlgC. The enterotoxin egc gene cluster was present in most strains (95.23%, 20/21). Phylogenetic tree analysis indicated the ST59-t437-Ⅳa(2B) as the principal evolutionary branch of foodborne MRSA. Conclusions In this study, foodborne MRSA has multiple drug resistance, high virulence, and a certain degree of biofilm formation ability, and carries clinically significant virulence genes. The virulence of the strain is related to its drug resistance, biofilm formation ability, and virulence gene carriage. Foodborne; methicillin-resistant Staphylococcus aureus; drug resistance; toxicity; biofilm; molecular characteristics
- Full text:20251112100746262509.Phenotypic and molecular epidemiological characteristics of foodborne methicillin-resistant Staphylococcus aureus.pdf
