医院和社区获得性感染耐甲氧西林金黄色葡萄球菌的耐药及基因组比较OA

Objective To analyze antimicrobial susceptibility phenotypes,molecular characteristics,and genetic evolution of healthcare-associated(HA)and community-associated(CA)methicillin-resistant Staphylococcus aureus(MRSA)strains in Pudong area,Shanghai,and provide data support for precise prevention and control.Methods From June to December 2024,a total of 101 MRSA strains were collected from 8 hospitals and divided into HA-MRSA and CA-MRSA groups.Antimicrobial resistance rate,as well as resistance and virulence genes of two groups of MRSA were compared.Multilocus sequence typing(MLST)and phylogenetic analysis were per-formed.Results Among the 101 MRSA strains,63 were CA-MRSA and 38 were HA-MRSA,with sputum being the main specimen type.The resistance rates of HA-MRSA to levofloxacin and tetracycline were both higher than CA-MRSA(both P<0.05).No strains resistant to furantoin,vancomycin,and rifampicin were detected.101 MRSA strains carried 45 resistance genes of 13 classes,carrying rates of mec I,mec R1,ant(4')-Ib,erm A,and tet M in HA-MRSA were all higher than in CA-MRSA(all P<0.05).The carrying rates of the disinfectant-resistant gene qac A in two groups of MRSA were high(26.32%and 15.87%,respectively).101 MRSA strains carried 4 enterotoxin genes,including sea and seb;the highest carriage rate in both groups was that of seb gene;Panton-Valentine leukocidin(PVL)was co-encoded by the luk S-PV and luk F-PV genes,and the carrying rate of luk F-PV in HA-MRSA was higher than in CA-MRSA(89.47%vs 65.08%,P<0.05).Three ST22 MRSA strains carried both luk S-PV and luk F-PV genes,and one of them also carried tsst-1 gene.A total of 14 STs were detected from 101 MRSA strains,with ST764(53.47%),ST398(13.86%),and ST59(7.92%)being the main types.Antimicrobial resistance genes for phosphonic acid and mupirocin,as well as disinfectant-resistant genes only presented in ST764.Single nucleotide polymorphism(SNP)-based phylogenetic tree showed that HA-MRSA and CA-MRSA distributed alternately.Conclusion HA-MRSA possesses higher resistance rates and higher carriage rates of resistance and virulence genes than CA-MRSA,indicating a more severe resistance situation and abundant STs.It is necessary to establish a hospital-community integrated monitoring and intervention network and implement coordinated comprehensive prevention and control.