Characterization of Ba813 harbouring Bacillus cereus in patients with haematological malignancy and hospital environments at a medical centre in Japan
Characterization of Ba813 harbouring Bacillus cereus in patients with haematological malignancy and hospital environments at a medical centre in Japan
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DOI：
10.1099/jmm.0.001212
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发表时间：
2020-01-01
影响因子：
3
通讯作者：
Kaku, Mistuo
中科院分区：
文献类型：
--
作者：
Aoyagi, Tetsuji;Kishihara, Yasuhiro;Kaku, Mistuo
介绍。窝藏炭疽芽孢杆菌特异性染色体标记物Ba813的蜡样芽孢杆菌存在于表现严重的患者中，可引起院内暴发。我们在医院环境中评估了Ba813（+）蜡样芽孢杆菌的遗传特征和毒力。3例中性粒细胞减少合并血液学恶性肿瘤患者在短时间内发生蜡样芽孢杆菌血症。从血液科病房不同部位分离到15株蜡样芽孢杆菌。对18株菌株进行了Ba813-和炭疽芽孢杆菌相关毒力、食物中毒相关毒力、遗传多样性、细菌活力和生物膜形成等方面的评价。33%（1/3）的患者和66%（9/15）的医院环境检出Ba813（+）蜡样芽孢杆菌。18株被划分为2个主要聚类（进化枝1和进化枝2），14株被划分为进化枝1。所有Ba813（+）菌株包括4个序列类型，均被划分为与炭疽谱系关系最密切的蜡样ⅲ谱系1枝/分支。2株属于演化支1/非蜡样ⅲ的菌株携带炭疽芽孢杆菌相关的帽基因，但不携带Ba813基因。蜡样芽孢杆菌，包括Ba813（+）菌株，其肠毒素基因的流行率明显低于进化枝2菌株。在蜡样芽孢杆菌进化支系1中，Ba813（+）菌株的游动能动性和生物膜形成能力显著高于Ba813（-）菌株。与炭疽芽孢杆菌有亲缘关系的Ba813（+）蜡样芽孢杆菌在血液科病房大量存在。Ba813（+）蜡样芽孢杆菌具有高运动性和生物膜形成能力，在医院环境中极易传播，可能成为医院获得性感染。
Introduction. Bacillus cereus harbouring Ba813, a specific chromosomal marker of Bacillus anthtacis, is found in patients with severe manifestations and causes nosocomial outbreaks.Aim. We assessed the genetic characteristics and virulence of Ba813(+) B. cereus in a hospital setting.Methodology. Three neutropenic patients with haematological malignancy developed B. cereus bacteraemia within a short period. Fifteen B. cereus were isolated from different sites in a haematology ward. A total of 18 isolates were evaluated for Ba813- and B. anthracis-related virulence, food poisoning-related virulence, genetic diversity, bacteria motility and biofilm formation.Results. Ba813(+) B. cereus was detected in 33% (1/3) of patients and 66% (9/15) of the hospital environment. The 18 strains were divided into 2 major clusters (clade 1 and clade 2), and 14 strains were classified into clade 1. All Ba813(+) strains, including four sequence types, were classified into clade 1/the cereus III lineage, which is most closely related to the anthracis lineage. Two strains belonging to clade 1/non-cereus III carried the B. anthracis-associated cap gene, but not Ba813. B. cereus, including Ba813(+) strains, had significantly lower prevalence of enterotoxin genes than clade 2 strains. In clade 1, B. cereus, Ba813(+) strains showed significantly higher swimming motility and biofilm formation ability than Ba813(-) strains.Conclusion. Ba813(+) B. cereus, which are genetically closely related to B. anthracis, were abundant in a haematological ward. Ba813(+) B. cereus with high motility and biofilm formation abilities may spread easily in hospital environments, and could become a hospital-acquired infection.