Catheter-associated urinary tract infections in intensive care units

The purpose of this review is to analyze literature concerning the diagnosis, prevention, and management of catheter-associated urinary tract infection (CAUTI) occurring in patients hospitalized in the intensive care unit (ICU). Analysis was performed from personal and "Pubmed" data, crossing the following keywords: "urinary tract infection", "catheter', and "intensive care unit". Few clinical trials including ICU patients were found despite the abundance of expert opinions. There is no consensus on the use of urinary reagent tests for diagnosis. The prevention of CAUTI in ICU patients does not require expensive devices. Neither complex closed drainage systems nor silver-coated urinary catheters have demonstrated efficacy in comparative randomized clinical trials. Bladder irrigation should not be used, except when an obstruction of the catheter is highly likely. The administration of prophylactic antimicrobial therapy, although effective in reducing the incidence of urinary bacteria, cannot be recommended in ICU patients. The management of CAUTI in ICU patients has not been evaluated in clinical trials. The level of evidence provided in this field is weak, and underlines the need for randomized studies to improve management of patients.     

An in vitro urinary tract catheter system to investigate biofilm development in catheter-associated urinary tract infections

Biofilm development in urinary tract catheters is an often underestimated problem. However, this form of infection leads to high mortality rates and causes significant costs in health care. Therefore, it is important to analyze these biofilms and establish avoiding strategies. In this study a continuous flow-through system for the cultivation of biofilms under catheter-associated urinary tract infection conditions was established and validated. The in vitro urinary tract catheter system implies the composition of urine (artificial urine medium), the mean volume of urine of adults (1 mL min^-1), the frequently used silicone catheter (foley silicon catheter) as well as the infection with uropathogenic microorganisms like Pseudomonas aeruginosa. Three clinical isolates from urine of catheterized patients were chosen due to their ability to form biofilms, their mobility and their cell surface hydrophobicity. As reference strain P. aeruginosa PA14 has been used. Characteristic parameters as biofilm thickness, specific biofilm growth rate and substrate consumption were observed. Biofilm thicknesses varied from 105 ± 16 μm up to 246 ± 67 μm for the different isolates. The specific biofilm growth rate could be determined with a non invasive optical biomass sensor. This sensor allows online monitoring of the biofilm growth in the progress of the cultivation.     

An in vitro urinary tract catheter system to investigate biofilm development in catheter-associated urinary tract infections

Biofilm development in urinary tract catheters is an often underestimated problem. However, this form of infection leads to high mortality rates and causes significant costs in health care. Therefore, it is important to analyze these biofilms and establish avoiding strategies. In this study a continuous flow-through system for the cultivation of biofilms under catheter-associated urinary tract infection conditions was established and validated. The in vitro urinary tract catheter system implies the composition of urine (artificial urine medium), the mean volume of urine of adults (1 mL min^–1), the frequently used silicone catheter (foley silicon catheter) as well as the infection with uropathogenic microorganisms like Pseudomonas aeruginosa. Three clinical isolates from urine of catheterized patients were chosen due to their ability to form biofilms, their mobility and their cell surface hydrophobicity. As reference strain P. aeruginosa PA14 has been used. Characteristic parameters as biofilm thickness, specific biofilm growth rate and substrate consumption were observed. Biofilm thicknesses varied from 105 ± 16 μm up to 246 ± 67 μm for the different isolates. The specific biofilm growth rate could be determined with a non invasive optical biomass sensor. This sensor allows online monitoring of the biofilm growth in the progress of the cultivation.     

Neomycin in urinary tract infections; a clinical evaluation

Neomycin was effective in treating 31 cases of severe Gram-negative bacillary urinary tract infections sensitive to neomycin and resistant to other agents. The recommended dosage schedule of 0.5 gm. every 12 hours for five days was demonstrated to be relatively safe. However, close watch should be maintained for signs of nephrotoxicity and ototoxicity.