目的:了解儿童骨与关节感染(BJI)耐甲氧西林金黄色葡萄球菌(MRSA)的特点。
方法:选择2013-2022年复旦大学附属儿科医院收治的BJI患者338例。人口统计信息,微生物学培养结果和实验室发现,包括白细胞计数(WBC),C反应蛋白(CRP),降钙素原(PCT),白细胞介素-6(IL-6),收集和分析红细胞沉降率(ESR)。MRSA通过抗菌药物敏感性试验证实。随机选择其他MRSA引起的感染进行比较。筛选了23个MRSA菌株的毒力和抗菌素抗性(AMR)基因。使用PCR扩增和测序进行多位点序列分型(MLST)和葡萄球菌蛋白A(spa)分型。
结果:在BJI中确定的病原体中,MRSA占21.0%(47/224)。BJI患者初始CRP水平较高,白细胞计数(WBC)和IL-6。ST59(43.9%)和t437(37.6%)是从儿童中分离出的主要MRSA亚型。BJI的主要基因型为ST59-t437(29.8%)和ST22-t309(14.9%),高携带溶血素,包括hla(94.4-100%),hlb(66.2-93.3%),和hld(100%)。值得注意的是,Panton-Valentine杀白细胞素(pvl)在ST22-t309-MRSA中的患病率很高(53.3%)。其他毒力基因包括tst,与ST59-t437-MRSA(4.2-9.9%)相比,ST22-t309-MRSA(40.0-46.7%)中更常见的是seg和sei.MRSA中的高携带AMR基因包括aph(3')/III(66.7-80%),ermB(57.5-73.3%)和ermC(66.7-78.9%)。MRSA对红霉素(52.0-100%)和克林霉素(48.0-92.5%)具有高耐药性,不同基因型对抗生素的敏感性存在差异。
结论:BJI中主要的MRSA基因型是ST59-t437,其次是ST22-t309,pvl基因的患病率更高。因此需要在儿科BJI感染中连续监测pvl阳性ST22-t309-MRSA。
OBJECTIVE: To investigate the characteristics of Methicillin-Resistant Staphylococcus aureus (MRSA) in bone and joint infection (BJI) among children.
METHODS: A total of 338 patients diagnosed with BJI from 2013 to 2022 in Children\'s Hospital of Fudan University were enrolled. Demographic information, microbiology culture results and laboratory findings, including white blood counts (WBC), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), and erythrocyte sedimentation rate (ESR) were collected and analyzed. MRSA was confirmed by antimicrobial susceptibility testing. Other MRSA-caused infections were randomly selected for comparison. Twenty-three virulence and antimicrobial resistance (AMR) genes were screened for MRSA strains. Multilocus sequence typing (MLST) and Staphylococcal protein A (spa) typing were performed using PCR amplification and sequencing.
RESULTS: Of the identified pathogens in BJI, MRSA accounted for 21.0% (47/224). Patients with BJI had high levels of initial CRP, white blood cell count (WBC) and IL-6. ST59 (43.9%) and t437 (37.6%) were the main MRSA subtypes isolated from the children. The major genotypes in BJI were ST59-t437 (29.8%) and ST22-t309 (14.9%), with high carriage of hemolysins including hla (94.4-100%), hlb (66.2-93.3%), and hld (100%). Notably, Panton-Valentine leukocidin (pvl) had a high prevalence (53.3%) in ST22-t309-MRSA. Other virulence genes including tst, seg and sei were more commonly detected in ST22-t309-MRSA (40.0-46.7%) than in ST59-t437-MRSA (4.2-9.9%). High-carriage AMR genes in MRSA included aph(3\')/III (66.7-80%), ermB (57.5-73.3%) and ermC (66.7-78.9%). MRSA presented high-resistance to erythromycin (52.0-100%) and clindamycin (48.0-92.5%), different genotypes displayed variation in their susceptibilities to antibiotics.
CONCLUSIONS: The major MRSA genotype in BJI was ST59-t437, followed by ST22-t309, with a higher prevalence of the pvl gene. Continuous surveillance of pvl-positive ST22-t309-MRSA in pediatric BJI infections is thus required.