Capsule Thickness, Not Biofilm Formation, Gives Rise to Mucoid Acinetobacter baumannii Phenotypes That are More Prevalent in Long-Term Infections: A Study of Clinical Isolates from a Hospital in China
Capsule Thickness, Not Biofilm Formation, Gives Rise to Mucoid Acinetobacter baumannii Phenotypes That are More Prevalent in Long-Term Infections: A Study of Clinical Isolates from a Hospital in China
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荚膜厚度而非生物膜形成导致了在长期感染中更常见的粘液鲍曼不动杆菌表型：对中国某医院临床分离株的研究
DOI：
10.2147/idr.s230178
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发表时间：
2020-01-01
影响因子：
3.9
通讯作者：
Zhou, Zhihui
中科院分区：
文献类型：
--
作者：
Hu, Lihua;Shi, Yue;Zhou, Zhihui
背景：鲍曼不动杆菌是一种重要的医院感染病原体，其耐药菌株的数量不断增加。集落可以有光滑或无光泽的外观，但也表现出粘糊糊的，粘液样生长，与后者越来越多地孤立在患者近年来。从总共56名患者中分离鲍曼不动杆菌菌株，发现所有患者都被粘液菌株感染，其中4名患者除了粘液菌株外还具有Matt表型。观察菌落和荚膜的形态。测定抗生素敏感性，结晶紫染色法测定生物膜形成能力。对所有菌株进行全基因组测序（WGS），然后进行核心基因组多位点序列分型（cgMLST）和耐药基因分析。最后，我们选择了一部分分离物在大蜡螟模型中进行毒力测试。结果：我们观察到粘液型菌株中的荚膜比无光泽型菌株中的荚膜大得多。但粘液样表型与菌株产生的生物膜量无关。几乎所有的粘液都是A型。鲍曼不动杆菌是多药耐药菌株，含有多种抗生素耐药基因。粘液型鲍曼不动杆菌的ST型主要为ST 191和ST 195，其中ST 191株毒力较强，ST 195株毒力较弱。鲍曼不动杆菌对大多数抗生素耐药，部分菌株毒力强，临床应引起重视。
Background: Acinetobacter baumannii is a nosocomial pathogen of critical importance due to the increasing numbers of antibiotic-resistant isolates. Colonies can have a smooth or matt appearance, but also exhibit slimy, mucoid growth, with the latter being increasingly isolated in patients in recent years.Methods: We isolated 60 A. baumannii strains from altogether 56 patients and found that all patients were infected by mucoid strains, with four patients having also matt phenotypes in addition to the mucoid ones. The morphology of the colonies and capsules was observed. The antibiotics susceptibilities were tested, and the biofilm formation ability was determined by crystal violet staining. The whole-genome sequencing (WGS) was performed on all the strains, and then the core genome multilocus sequence typing (cgMLST) and drug resistance gene analysis were performed. Finally, a part of isolates were selected to test virulence in a Galleria mellonella model.Results: We observed much larger capsules in the mucoid strains compared to the matt isolates. But the mucoid phenotype did not correlate with the amount of biofilm produced by the strain. Almost all mucus-type A. baumannii were multi-drug resistant isolates, containing various antibiotic resistance genes. The main ST types of mucoid-type A.baumannii were ST191 and ST195, of which ST191 isolates were more virulence, while ST195 isolates were weaker.Conclusion: The mucoid A. baumannii had resistance to most antibiotics and some strains had high virulence, which should be paid attention in clinical.