In recent years, the incidence of pediatric septic arthritis caused by Streptococcus pneumoniae has been quite low. The pneumococcal conjugate vaccine PCV10 is the available vaccine included in the Bulgarian national immunization program. PCV10 reduces the incidence of invasive diseases, but non-vaccinal serotypes like 19A, the etiologic agent of the case of septic arthritis reported herein in a 3-year-old boy. The synovial fluid was positive for S. pneumoniae. The patient was treated with vancomycin during hospitalization and trimethoprim/sulfamethoxazole was recommended for at-home treatment. The isolate was subjected to latex agglutination, antimicrobial susceptibility testing, PCR detection for macrolide-resistance genes, and MLST. The strain revealed ST695 and a genotype previously associated with vaccine serotype 4. The incidence of pneumococcal infections caused by capsule-switching events and non-PCV10 serotypes is expected to increase.

近年来，肺炎链球菌引起的小儿化脓性关节炎的发病率已经很低了。肺炎球菌结合疫苗 PCV10 是保加利亚国家免疫计划中包含的可用疫苗。PCV10 可降低侵袭性疾病的发病率，但非疫苗血清型如 19A 是本文报告的一名 3 岁男孩化脓性关节炎病例的病原体。滑液对肺炎链球菌呈阳性. 患者住院期间接受万古霉素治疗，推荐甲氧苄氨嘧啶/磺胺甲恶唑居家治疗。对分离株进行乳胶凝集、药敏试验、大环内酯类耐药基因PCR检测和MLST。该菌株显示 ST695 和先前与疫苗血清型 4 相关的基因型。由胶囊转换事件和非 PCV10 血清型引起的肺炎球菌感染的发生率预计会增加。