Bacillus cereus is ubiquitous in nature, found in environments such as soil, plants, air, and part of the insect and human gut microbiome. The ability to produce endospores and biofilms contribute to their pathogenicity, classified in two types of food poisoning: diarrheal and emetic syndromes. Here we report gap-free, whole-genome sequences of two B. cereus strains isolated from air samples and analyse their emetic and diarrheal potential. Genome assemblies of the B. cereus strains consist of one chromosome and seven plasmids each. The genome size of strain SGAir0260 is 6.30-Mb with 6590 predicted coding sequences (CDS) and strain SGAir0263 is 6.47-Mb with 6811 predicted CDS. Macrosynteny analysis showed 99% collinearity between the strains isolated from air and 90.2% with the reference genome. Comparative genomics with 57 complete B. cereus genomes suggests these strains from air are closely associated with strains isolated from foodborne illnesses outbreaks. Due to virulence potential of B. cereus and its reported involvement in nosocomial infections, antibiotic resistance analyses were performed and confirmed resistance to ampicillin and fosfomycin, with susceptibility to ciprofloxacin, tetracycline and vancomycin in both strains. Phylogenetic analysis combined with detection of haemolytic (hblA, hblC, and hblD) and non-haemolytic (nheA, nheB, and nheC) enterotoxin genes in both air-isolated strains point to the diarrheic potential of the air isolates, though not emetic. Characterization of these airborne strains and investigation of their potential disease-causing genes could facilitate identification of environmental sources of contamination leading to foodborne illnesses and nosocomial infections transported by air.

中文翻译：

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室内空气中分离的蜡状芽孢杆菌菌株的基因组特征与比较

蜡状芽孢杆菌在自然界无处不在，存在于土壤，植物，空气以及部分昆虫和人类肠道微生物组等环境中。产生内生孢子和生物膜的能力有助于其致病性，分为两种食物中毒类型：腹泻和呕吐综合症。在这里，我们报告了从空气样本中分离出的两个蜡状芽孢杆菌菌株的无间隙全基因组序列，并分析了它们的催吐和腹泻潜能。蜡状芽孢杆菌菌株的基因组装配体由一个染色体和七个质粒组成。SGAir0260菌株的基因组大小为6.30-Mb，具有6590个预测的编码序列（CDS），SGAir0263菌株的基因组大小为6.47-Mb，具有6811个预测的CDS。宏观同步分析显示，从空气中分离出的菌株与参考基因组之间的共线性为99％，90.2％。比较基因组学，具有57个完整的B。蜡样藻基因组表明，这些来自空气的菌株与从食源性疾病暴发中分离出的菌株密切相关。由于蜡状芽孢杆菌具有潜在毒性，并且据报道其参与了医院感染，因此进行了抗生素耐药性分析，并确认了对氨苄西林和磷霉素的耐药性，两种菌株均对环丙沙星，四环素和万古霉素敏感。系统发育分析与检测两种空气分离菌株中溶血性（hblA，hblC和hblD）和非溶血性（nheA，nheB和nheC）肠毒素基因相结合，指出了空气分离物的腹泻潜力，尽管不是呕吐物。