Zhou Menglan, Wang Ziran, Zhang Li, Kudinha Timothy, An Haoran, Qian Chenyun, Jiang Bin, Wang Yao, Xu Yingchun, Liu Zhengyin, Zhang Hong, Zhang Jingren
State Key Laboratory of Complex Severe and Rare Diseases, Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China.
Front Microbiol. 2022 Jan 13;12:798750. doi: 10.3389/fmicb.2021.798750. eCollection 2021.
is an important human pathogen that can cause severe invasive pneumococcal diseases (IPDs). The aim of this multicenter study was to investigate the serotype and sequence type (ST) distribution, antimicrobial susceptibility, and virulence of strains causing IPD in China. A total of 300 invasive isolates were included in this study. The serotype, ST, and antimicrobial susceptibility of the strains, were determined by the Quellung reaction, multi-locus sequence typing (MLST) and broth microdilution method, respectively. The virulence level of the strains in the most prevalent serotypes was evaluated by a mouse sepsis model, and the expression level of well-known virulence genes was measured by RT-PCR. The most common serotypes in this study were 23F, 19A, 19F, 3, and 14. The serotype coverages of PCV7, PCV10, PCV13, and PPV23 vaccines on the strain collection were 42.3, 45.3, 73.3 and 79.3%, respectively. The most common STs were ST320, ST81, ST271, ST876, and ST3173. All strains were susceptible to ertapenem, levofloxacin, moxifloxacin, linezolid, and vancomycin, but a very high proportion (>95%) was resistant to macrolides and clindamycin. Based on the oral, meningitis and non-meningitis breakpoints, penicillin non-susceptible (PNSP) accounted for 67.7, 67.7 and 4.3% of the isolates, respectively. Serotype 3 strains were characterized by high virulence levels and low antimicrobial-resistance rates, while strains of serotypes 23F, 19F, 19A, and 14, exhibited low virulence and high resistance rates to antibiotics. Capsular polysaccharide and non-capsular virulence factors were collectively responsible for the virulence diversity of strains. Our study provides a comprehensive insight into the epidemiology and virulence diversity of strains causing IPD in China.
是一种重要的人类病原体，可导致严重的侵袭性肺炎球菌疾病（IPD）。这项多中心研究的目的是调查中国引起IPD的菌株的血清型和序列类型（ST）分布、抗菌药物敏感性及毒力。本研究共纳入300株侵袭性分离株。分别通过荚膜肿胀反应、多位点序列分型（MLST）和肉汤微量稀释法测定菌株的血清型、ST和抗菌药物敏感性。通过小鼠败血症模型评估最常见血清型菌株的毒力水平，并通过RT-PCR检测知名毒力基因的表达水平。本研究中最常见的血清型为23F、19A、19F、3和14。PCV7、PCV10、PCV13和PPV23疫苗对所收集菌株的血清型覆盖率分别为42.3%、45.3%、73.3%和79.3%。最常见的STs为ST320、ST81、ST271、ST876和ST3173。所有菌株对厄他培南、左氧氟沙星、莫西沙星、利奈唑胺和万古霉素敏感，但对大环内酯类和克林霉素耐药比例非常高（>95%）。根据口服、脑膜炎和非脑膜炎的断点标准，青霉素不敏感（PNSP）菌株分别占分离株的67.7%、67.7%和4.3%。3型血清型菌株的特点是毒力水平高且抗菌药物耐药率低，而23F、19F、19A和14型血清型菌株毒力低且对抗生素耐药率高。荚膜多糖和非荚膜毒力因子共同导致了菌株的毒力多样性。我们的研究全面深入地了解了中国引起IPD的菌株的流行病学和毒力多样性。
