Assessment of the growth inhibition and anti-biofilm activity of aptamer (PmA2G02) against Proteus mirabilis 1429T.

Proteus mirabilis is known to cause Catheter-associated urinary tract infections (CAUTIs), which exhibit virulence factors linked to forming biofilms. Aptamers have recently been explored as potential anti-biofilm agents. This study demonstrates the anti-biofilm activity of aptamer (PmA2G02) targeting P. mirabilis 1429T, a pathogenic bacteria known to cause Catheter-associated urinary tract infections (CAUTIs). The studied aptamer inhibited biofilm formation, swarming motility, and cell viability at a concentration of 3 µM. The study also showed that the PmA2G02 had a binding affinity towards fimbrial outer membrane usher protein (PMI1466), flagellin protein (PMI1619), and regulator of swarming behavior (rsbA), which are responsible for adhesion, motility, and quorum sensing, respectively. Crystal violet assay, SEM, and confocal imaging confirmed the effectiveness of the PmA2G02 as an anti-biofilm agent. Moreover, as verified by qPCR, the expression levels of fimD, fliC2, and rsbA were significantly reduced compared to the untreated group. This study suggests that aptamer may be a potential alternative to traditional antibiotics for the treatment of CAUTIs caused by P. mirabilis. These findings shed light on the mechanisms by which the aptamer inhibits biofilm formation.

Assessment of Proteus mirabilis Antigen Immunological Complexes by Atomic Force Microscopy.

Atomic force microscopy (AFM) is being increasingly used to directly measure protein interactions in nearly physiological environments. Here, protocols for atomic force microscopy (AFM) for visualization of antigen-antibody complexes are presented. The technique is used to demonstrate complexes formed by rheumatoid arthritis patient antibodies with lipopolysaccharide (LPS) isolated from P. mirabilis (O3) strain S1959 and a synthetic antigen (LPS epitope of 6 N-alpha-(D-galacturonoyl)-L-lysine residues).

Assessment of PEO/PTMO multiblock copolymer/segmented polyurethane blends as coating materials for urinary catheters: in vitro bacterial adhesion and encrustation behavior.

The effective long-term use of indwelling urinary catheters has often been hindered by catheter-associated infection and encrustation. In this study, the suitability of poly(ethylene oxide) (PEO)-based multiblock copolymer/segmented polyurethane (SPU) blends as coating materials for the commercial urinary catheters was assessed by measuring swellability, bacterial adhesion, and encrustation behavior. When exposed to PBS (pH 7.4), the blends absorbed a significant amount of water, which was proportional to the copolymer content. It was demonstrated from bacterial adhesion tests that compared to bare SPU, the blend surfaces could significantly reduce the adhesion of E. coli, P. mirabilis, and S. epidermidis; the number of adherent bacteria correlated with the amount of copolymer additive. indicating that the swellability of the blends affected bacterial adhesion. Of the bacteria studied, the greatest effect of the copolymer additive was observed in S. epidermidis adhesion, in which there was an 85% decrease compared to bare SPU with a small amount of copolymer additive as low as 5% based on a dried blend. By using an artificial bladder model, allowing the catheter to be blocked by encrustation, it was revealed that the blend surfaces could effectively resist encrustation. The duration of patency was extended up to 20 +/- 3.1 h on the blend surface containing 10% of the copolymer additive, whereas the silicone-coated catheter, a control, required the least time for blockage, 7.8 +/- 3.1 h. The superior characteristics of the blends compared to other surfaces might be attributed to their PEO-rich surfaces, produced by the migration of PEO phase in the copolymer chain of the blends in an aqueous environment, and provide promising potential as a coating material on the urinary catheter for long-term catheterization.

Assessment of technique for rapid detection of Escherichia coli and Proteus species in urine by head-space gas-liquid chromatography.

A test depending on the production of ethanol by Escherichia coli from lactose and dimethyl disulfide by Proteus spp. from methionine in the early exponential phase of growth and the detection of these products by head-space gas-liquid chromatography has been applied to 75 specimens of urine selected to provide the most stringent trial of the test. The test was found to be rapid and reliable for the commonest findings in the microbiological examination of urine. In 3 to 4 h it detected "significant" numbers (greater than 10(5)/ml) of E. coli or of Proteus mirabilis or P. inconstans A, identified as Proteus spp., in 23 urines. It recorded the absence of infection from 32 urines containing borderline or "not significant" numbers of any organism. Significant numbers of other organisms in 13 urines were not mistaken for E. coli or Proteus spp. However, the test was less successful for some less common findings. Klebsiella ozenae in significant numbers in one urine was mistaken for E. coli. P. morganii in significant numbers in one urine was not detected. E. coli or P. mirabilis mixed with significant numbers of another organism were not detected in four out of five urines. The technique is simple and could be automated. It appears to merit more extensive trial in a hospital laboratory and further development to detect and correctly identify more species that cause urinary tract infections.