Vyas Heema K N, Indraratna Anuk D, Everest-Dass Arun, Packer Nicolle H, De Oliveira David M P, Ranson Marie, McArthur Jason D, Sanderson-Smith Martina L
Illawarra Health and Medical Research Institute, Wollongong 2522, Australia.
School of Chemistry and Molecular Bioscience, Molecular Horizons, University of Wollongong, Wollongong 2522, Australia.
Antibiotics (Basel). 2020 Nov 4;9(11):775. doi: 10.3390/antibiotics9110775.
Group A (GAS) causes 700 million infections and accounts for half a million deaths per year. Antibiotic treatment failure rates of 20-40% have been observed. The role host cell glycans play in GAS biofilm formation in the context of GAS pharyngitis and subsequent antibiotic treatment failure has not been previously investigated. GAS serotype M12 GAS biofilms were assessed for biofilm formation on Detroit 562 pharyngeal cell monolayers following enzymatic removal of all -linked glycans from pharyngeal cells with PNGase F. Removal of -linked glycans resulted in an increase in biofilm biomass compared to untreated controls. Further investigation into the removal of terminal mannose and sialic acid residues with α1-6 mannosidase and the broad specificity sialidase (Sialidase A) also found that biofilm biomass increased significantly when compared to untreated controls. Increases in biofilm biomass were associated with increased production of extracellular polymeric substances (EPS). Furthermore, it was found that M12 GAS biofilms grown on untreated pharyngeal monolayers exhibited a 2500-fold increase in penicillin tolerance compared to planktonic GAS. Pre-treatment of monolayers with exoglycosidases resulted in a further doubling of penicillin tolerance in resultant biofilms. Lastly, an additional eight GAS -types were assessed for biofilm formation in response to terminal mannose and sialic acid residue removal. As seen for M12, biofilm biomass on monolayers increased following removal of terminal mannose and sialic acid residues. Collectively, these data demonstrate that pharyngeal cell surface glycan structures directly impact GAS biofilm formation in a strain and glycan specific fashion.
A组链球菌（GAS）每年导致7亿例感染，造成50万人死亡。已观察到抗生素治疗失败率为20%-40%。宿主细胞聚糖在GAS咽炎及随后抗生素治疗失败背景下在GAS生物膜形成中所起的作用此前尚未得到研究。在用肽-N-糖苷酶F从咽部细胞中酶促去除所有连接的聚糖后，评估了GAS血清型M12在底特律562咽部细胞单层上的生物膜形成情况。与未处理的对照相比，去除连接的聚糖导致生物膜生物量增加。用α1-6甘露糖苷酶和广谱特异性唾液酸酶（唾液酸酶A）进一步研究去除末端甘露糖和唾液酸残基后发现，与未处理的对照相比，生物膜生物量也显著增加。生物膜生物量的增加与细胞外聚合物（EPS）产量的增加有关。此外，还发现与浮游GAS相比，在未处理的咽部单层上生长的M12 GAS生物膜对青霉素的耐受性提高了2500倍。用外切糖苷酶对单层进行预处理导致所得生物膜中青霉素耐受性进一步加倍。最后，评估了另外8种GAS血清型对去除末端甘露糖和唾液酸残基后的生物膜形成情况。如M12所见，去除末端甘露糖和唾液酸残基后，单层上的生物膜生物量增加。总的来说，这些数据表明咽部细胞表面聚糖结构以菌株和聚糖特异性方式直接影响GAS生物膜形成。
