Successful antibiotic treatment of infections relies on accurate and rapid identification of the infectious agents. Pseudomonas aeruginosa is implicated in a wide range of human infections that mostly become complicated and life threating, especially in immunocompromised and critically ill patients. Conventional microbiological methods take more than three days to obtain accurate results. Pyocyanin is a distinctive electroactive biomarker for Pseudomonas aeruginosa . Here, we have prepared polyaniline/gold nanoparticles decorated ITO electrode and tested it to establish a rapid, diagnostic and highly sensitive pyocyanin sensor in a culture of Pseudomonas aeruginosa clinical isolates with high selectivity for traces of pyocyanin when measured in the existence of different interferences like vitamin C, uric acid, and glucose. The scanning electron microscopy and cyclic voltammetry techniques were used to characterize the morphology and electrical conductivity of the constructed electrode. The determined linear range for pyocyanin detection was from 238 μM to 1.9 μM with a detection limit of 500 nM. Compared to the screen-printed electrode used before, the constructed electrode showed a 4-fold enhanced performance. Furthermore, PANI/Au NPs/ITO modified electrodes have demonstrated the ability to detect pyocyanin directly in Pseudomonas aeruginosa culture without any potential interference with other species.

Pseudomonas aeruginosa is the most common pathogenic gram-negative bacteria causing corneal ulcers globally. In severe cases, often after trauma and eye injury, corneal destruction progresses rapidly and may be completed within 24–48 h causing blindness. In our preliminary work, we have established an ultrasensitive polyaniline (PANI)/gold nanoparticles (Au NPs)/indium tin oxide (ITO) modified sensor for rapid detection of pyocyanin (PYO) in P. aeruginosa infections with a linear range from 238 μM to 1.9 μM and a detection limit of 500 nM. In the present study, we evaluated the efficiency of the established modified electrochemical sensor in the diagnosis of P. aeruginosa in 50 samples collected from patients suffering from corneal ulcers. The obtained results were compared with the results gained by the screen-printed electrode, conventional techniques, automated identification method, and the amplification of the 16 s rRNA gene by PCR as a gold standard test for P. aeruginosa identification. We have found that the electrochemical detection of PYO by square wave voltammetry technique using PANI/Au NPs modified ITO electrode was the only technique showing 100% agreement with the molecular method in sensitivity, specificity, positive and negative predictive values when compared with the SPE, conventional and automated methods.

Background: Ureteral catheters are valuable indispensable devices may readily acquire biofilms on the inner or outer surfaces. This study evaluated the efficacies of ureteral catheters impregnated with ciprofloxacin, N-acetylcysteine each alone and in combination on microbial adherence.Methods: Antimicrobial durability of ureteral catheters coated, through instant dip method, with ciprofloxacin were determined using modified Kirby-Bauer method. Ciprofloxacin-coated catheters showed zones of inhibition ranged from 15 to 45 mm in diameter (baseline) against nine clinical strains recently isolated from patients undergoing ureteral stent removal. Segments coated with ciprofloxacin, N-acetylcysteine each alone and in combination, through instant dip method, were incubated with the tested microorganisms, washed, sonicated, cultured and the number of viable cells were determined.Results: Ciprofloxacin-coated catheters soaked in urine and incubated at 37 °C, maintained antimicrobial activities and produce zones of inhibition that measured 2-10 mm for at least 8 weeks. Effect of ciprofloxacin and N-acetylcysteine coated catheters on microbial adherence were found to be dose dependent. Catheters impregnated with ciprofloxacin/N-acetylcysteine showed the highest inhibitory effect on microbial adherence when compared with controls (85.5%-100%).Conclusion: Catheters impregnated with ciprofloxacin, using instant dip method, were shown to have broad spectrum, prolonged antimicrobial durability and high efficacy. On the other hand, Catheters impregnated with ciprofloxacin/NAC showed the highest inhibitory effect on microbial adherence to stent surfaces.

Background: Staphylococci are a common cause of catheter-associated urinary tract infections. The present study evaluated biofilm forming capacity and the presence of both icaA and icaD genes among staphylococci strains isolated from patients undergoing ureteral catheterization. Methodology: Different bacterial strains were isolated from urine and stents segments collected from 100 patients. Strains were identified by traditional microbiological methods. Stents were examined for biofilm using a scanning electron microscope (SEM). Staphylococcal isolates were tested for their ability to produce biofilm using the tissue culture plate assay method (TCP). The presence of icaA and icaD genes was determined by PCR technique. Results: Fifty-three staphylococcal strains were isolated and identified from 284 samples (18.7%). Forty-six staphylococcal strains were isolated from stent segment cultures while only seven strains were isolated from urine samples at the day of stent removal. S. aureus represented 6.3%, and S. epidermidis represented 12.3%. Out of the 18 S. aureus strains, 15 (83.3%) were biofilm producers and out of 35 S. epidermidis strains, 31 (88.6%) were biofilm producers. Staphylococcal strains were further classified as high (56.6%), moderate (30.2%) and non biofilm producers (13.2%). All biofilm producing strains were positive for icaA and icaD genes, and all biofilm negative strains were negative for both genes. Conclusion: Staphylococci isolated from catheter segments showed a higher extent of biofilm production than that isolated from urine samples. All biofilm producing staphylococci were positive for icaA and icaD genes, which indicates the important role of ica genes as virulence markers in staphylococcal infections associated with urinary catheterization.

Ni (II) and Co (II) complexes of thiosemicarbazide ligand (2-(anilinoacetyl)-N-(3-methylphenyl)hydrazine-1-carbothioamide(H 2 L B ) have been prepared and characterized by 1 HNMR, IR, elemental analyses, molar conductance, UVvisible spectra, magnetic susceptibility measurements, thermogravimetric analysis (TGA/DTG), and X-ray differaction pattern before and after irradiation.The results confirmed that gamma rays enhanced the stability of irradiated compounds compared with those non-irradiated. Density functional theory (DFT) calculations of synthesized compounds were completely optimized with respect to the energy using B3LYP level. DNA binding of compounds before and after gamma irradiation has been studied. Inhibitory effect on the growth of bacteria against gram-positive (Streptococcus pyogenes) and gram-negative (Escherichia coli) of synthesized compounds have been investigated. The results revealed that Ni (II) complex after gamma irradiation showed a higher antibacterial activity against gram positive and gram negative bacteria more than all investigated compounds. The ability of scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical by our synthesized compounds was investigated on the basis of the determination of IC 50 values.