Biofilm Associated Genotypes of Multiple Antibiotic Resistant Pseudomonas Aeruginosa

Abstract BackgroundPseudomonas 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. ResultsWe examined the genetic basis for biofilm production on polystyrene at room (22°C) and body temperature (37°C) within 280 P. aeruginosa. 69% of isolates (n=193) produced more biofilm at 22°C, whilst those producing more biofilm at 37°C had reduced genetic diversity. Using GWAS and pan-GWAS, we found a number of accessory genes significantly associated with this phenotype. Many of these are present on a 165kb 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. ConclusionsGWAS and pan-GWAS approaches have great potential as a first step in characterizing the genetic basis of novel bacterial phenotypes.