Spectrum and antibiotic resistance of catheter-associated urinary tract infections.

Catheter associated urinary tract infections (CAUTIs) are amongst the most common nosocomial infections and are also considered among the most common complications associated with indwelling urinary catheters. Most catheter associated infections are derived from the patient's own perineal flora, however the presence of a catheter increases the chance of being colonised by cross transmission of nosocomial bacteria as well. Most episodes of short-term catheter-associated bacteriuria are asymptomatic and are caused by single organisms, while long-term catheterisation promotes multibacterial infections and colonization. With prolonged duration of catheterization bacteriuria is considered universal because of the formation of biofilms on the surface of the catheter. Chronic indwelling catheters are an important reservoir of different multiresistant gram-negative organisms, therefore they are frequently isolated from CAUTIs. Treatment of catheter associated asymptomatic bacteriuria is not recommended because it will only promote the emergence of resistant organisms without effectively clearing the urine of catheterised patients.