Genome Sequence of the Urethral Isolate Pseudomonas aeruginosa RN21.

Pseudomonas aeruginosa is known to cause complicated urinary tract infections (UTI). The improved 7.0-Mb draft genome sequence of P. aeruginosa RN21, isolated from a patient with an acute UTI, was determined. It carries three (pro)phage genomes, genes for two restriction/modification systems, and a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system.

Genome Sequence of the Urethral Catheter Isolate Pseudomonas aeruginosa MH19.

Pseudomonas aeruginosa is a frequent agent of complicated catheter-associated urinary tract infections (CAUTIs). Here, we present the improved 7.1-Mb draft genome sequence of P. aeruginosa MH19, which was isolated from a patient with an acute hospital-acquired CAUTI. It includes unique genes not represented in other P. aeruginosa genomes.

Regulatory and metabolic networks for the adaptation of Pseudomonas aeruginosa biofilms to urinary tract-like conditions.

Biofilms of the Gram-negative bacterium Pseudomonas aeruginosa are one of the major causes of complicated urinary tract infections with detrimental outcome. To develop novel therapeutic strategies the molecular adaption strategies of P. aeruginosa biofilms to the conditions of the urinary tract were investigated thoroughly at the systems level using transcriptome, proteome, metabolome and enzyme activity analyses. For this purpose biofilms were grown anaerobically in artificial urine medium (AUM). Obtained data were integrated bioinformatically into gene regulatory and metabolic networks. The dominating response at the transcriptome and proteome level was the adaptation to iron limitation via the broad Fur regulon including 19 sigma factors and up to 80 regulated target genes or operons. In agreement, reduction of the iron cofactor-dependent nitrate respiratory metabolism was detected. An adaptation of the central metabolism to lactate, citrate and amino acid as carbon sources with the induction of the glyoxylate bypass was observed, while other components of AUM like urea and creatinine were not used. Amino acid utilization pathways were found induced, while fatty acid biosynthesis was reduced. The high amounts of phosphate found in AUM explain the reduction of phosphate assimilation systems. Increased quorum sensing activity with the parallel reduction of chemotaxis and flagellum assembly underscored the importance of the biofilm life style. However, reduced formation of the extracellular polysaccharide alginate, typical for P. aeruginosa biofilms in lungs, indicated a different biofilm type for urinary tract infections. Furthermore, the obtained quorum sensing response results in an increased production of virulence factors like the extracellular lipase LipA and protease LasB and AprA explaining the harmful cause of these infections.

Susceptibility of Pseudomonas aeruginosa urinary tract isolates and influence of urinary tract conditions on antibiotic tolerance.

Pseudomonas aeruginosa is an opportunistic human pathogen, which can cause severe urinary tract infections (UTIs). Because of the high intrinsic antibiotic resistance of P. aeruginosa and its ability to develop new resistances during antibiotic treatment, these infections are difficult to eradicate. The antibiotic susceptibility of 32 P. aeruginosa isolates from acute and chronic UTIs were analysed under standardized conditions showing 19% multi-drug resistant strains. Furthermore, the antibiotic tolerance of two P. aeruginosa strains to ciprofloxacin and tobramycin was analysed under urinary tract-relevant conditions which considered nutrient composition, biofilm growth, growth phase, and oxygen concentration. These conditions significantly enhance the antibiotic tolerance of P. aeruginosa up to 6000-fold indicating an adaptation of the bacterium to the specific conditions present in the urinary tract. This reversible phenomenon is possibly due to the increased formation of persister cells and is based on iron limitation in artificial urine. The results suggest that the general high antibiotic resistance of P. aeruginosa urinary tract isolates together with the increasing tolerance of P. aeruginosa grown under urinary tract conditions decrease the efficiency of antibiotic treatment of UTIs.

Genotypic and phenotypic characterization of Pseudomonas aeruginosa isolates from urinary tract infections.

Pseudomonas aeruginosa is one of the most frequent agents of urinary tract infections especially in patients with indwelling urethral catheters. A total of 30 P. aeruginosa isolates from urinary tract infections was investigated for their genotypic and phenotypic characteristics. 'Single Nucleotide Polymorphism' chip typing experiments in combination with bioinformatical cluster analyses allowed genotypic grouping of the isolates. Some similarities to strains from lung infections but also to environmental strains were observed. Finally, several urinary tract-specific groups were identified indicating a strong heterogeneity of the urethral isolates. Pyoverdin, protease, and phospholipase A production in combination with quorum sensing activity and biofilm formation were common phenotypic characteristics of these strains. In contrast, swarming phenotypes, the production of pyocyanin, and the extracellular enzymes phospholipase C and elastase were rarely observed. Interestingly, strains isolated from catheter-associated infections showed significantly enhanced biofilm formation, decreased motility, and a slightly increased expression of virulence factors in relation to isolates from acute urinary tract infections.