Redfern James, Wallace Janine, van Belkum Alex, Jaillard Magali, Whittard Elliot, Ragupathy Roobinidevi, Verran Joanna, Kelly Peter, Enright Mark Charles
Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester, United Kingdom.
bioMérieux SA, La Balme les Grottes, France.
BMC Genomics. 2021 Jul 26;22(1):572. doi: 10.1186/s12864-021-07818-5.
Pseudomonas aeruginosa is a ubiquitous environmental microorganism and also a common cause of infection. Its ability to survive in many different environments and persistently colonize humans is linked to its presence in biofilms formed on indwelling device surfaces. Biofilm promotes adhesion to, and survival on surfaces, protects from desiccation and the actions of antibiotics and disinfectants.
We examined the genetic basis for biofilm production on polystyrene at room (22 °C) and body temperature (37 °C) within 280 P. aeruginosa. 193 isolates (69 %) produced more biofilm at 22 °C than at 37 °C. Using GWAS and pan-GWAS, we found a number of accessory genes significantly associated with greater biofilm production at 22 °C. Many of these are present on a 165 kb region containing genes for heavy metal resistance (arsenic, copper, mercury and cadmium), transcriptional regulators and methytransferases. We also discovered multiple core genome SNPs in the A-type flagellin gene and Type II secretion system gene xpsD. Analysis of biofilm production of isolates of the MDR ST111 and ST235 lineages on stainless-steel revealed several accessory genes associated with enhanced biofilm production. These include a putative translocase with homology to a Helicobacter pylori type IV secretion system protein, a TA system II toxin gene and the alginate biosynthesis gene algA, several transcriptional regulators and methytransferases as well as core SNPs in genes involved in quorum sensing and protein translocation.
Using genetic association approaches we discovered a number of accessory genes and core-genome SNPs that were associated with enhanced early biofilm formation at 22 °C compared to 37 °C. These included a 165 kb genomic island containing multiple heavy metal resistance genes, transcriptional regulators and methyltransferases. We hypothesize that this genomic island may be associated with overall genotypes that are environmentally adapted to survive at lower temperatures. Further work to examine their importance in, for example gene-knockout studies, are required to confirm their relevance. GWAS and pan-GWAS approaches have great potential as a first step in examining the genetic basis of novel bacterial phenotypes.
铜绿假单胞菌是一种广泛存在于环境中的微生物，也是常见的感染源。它能够在多种不同环境中生存并持续定殖于人体，这与其在植入装置表面形成的生物膜有关。生物膜促进细菌在表面的黏附与存活，保护细菌免受干燥以及抗生素和消毒剂的作用。
我们检测了280株铜绿假单胞菌在室温（22℃）和体温（37℃）下在聚苯乙烯上产生生物膜的遗传基础。193株分离株（69%）在22℃时比在37℃时产生更多生物膜。使用全基因组关联研究（GWAS）和泛全基因组关联研究（pan-GWAS），我们发现了一些与22℃时更强生物膜产生显著相关的辅助基因。其中许多基因存在于一个165kb的区域，该区域包含重金属抗性（砷、铜、汞和镉）基因、转录调节因子和甲基转移酶基因。我们还在A型鞭毛蛋白基因和II型分泌系统基因xpsD中发现了多个核心基因组单核苷酸多态性（SNP）。对耐多药ST111和ST235谱系分离株在不锈钢上生物膜产生情况的分析揭示了几个与生物膜产生增强相关的辅助基因。这些基因包括一个与幽门螺杆菌IV型分泌系统蛋白具有同源性的假定转运酶、一个TA系统II毒素基因和藻酸盐生物合成基因algA、几个转录调节因子和甲基转移酶，以及参与群体感应和蛋白质转运的基因中的核心SNP。
使用遗传关联方法，我们发现了一些辅助基因和核心基因组SNP，它们与22℃时相比37℃时增强的早期生物膜形成有关。其中包括一个包含多个重金属抗性基因、转录调节因子和甲基转移酶的165kb基因组岛。我们推测这个基因组岛可能与在环境中适应较低温度生存的总体基因型有关。需要进一步开展工作，例如通过基因敲除研究来检验它们的重要性，以确认它们的相关性。GWAS和pan-GWAS方法作为研究新型细菌表型遗传基础的第一步具有巨大潜力。
