**9. Bladder catheterization**

detectable uropathogenic concentration in samples from permanent catheter or supraventricular puncture. Other researchers continue to regard the concentration of 105 CFU/ml in urine as a criterion for significant bacteriuria even in samples after catheterization [73]. Waites et al. reported that patients with 10 CFU/ml in urine have a 10% risk of a febrile episode, while the presence of pyuria is more associated with fever and shivering [73]. In patients receiving 40% IC, the source of bacteriuria was the upper urinary tract, while in 60%, the source was the lower urinary tract [74]. Pyuria was much higher in patients with upper urinary tract

68 Microbiology of Urinary Tract Infections - Microbial Agents and Predisposing Factors

Asymptomatic bacteriuria is defined as the presence of a significant number of urine microbes (105 CFU/ml) in patients without clinical symptoms or signs of infection. The incidence varies depending on the age of the patients, the sex and the presence or absence of functional or anatomical urinary tract abnormalities. Bladder catheterization is the most important predisposing factor for asymptomatic microbial growth. In hospitalized catheterized patients with an open urine collection system, the incidence of the asymptomatic microbial disease is 100%

Microorganisms most commonly isolated in bladder catheterized patients are *Escherichia coli*, Klebsiella, Proteus, Enterococcus, Enterobacter, Pseudomonas, Serratia, and Candida. Most are part of the microbial flora of the bowel colonizing the anterior part of the urethra. In patients with a bladder catheter for a short or long period of time, urine specimen collection should be taken by catheter puncture after meticulous antisepsis of the puncture site and not through the catheter's mouth. The presence of leucocytes with or without hematuria is taken into account but does not necessarily require the diagnosis of active infection. Asymptomatic bacteriuria in individuals with SCI requires treatment only in cases where symptomatic uri-

As mentioned, bacterial colonization of the skin and the urethra is an important source of bladder infection using catheters. Differences in microbial species and their presence in normal skin flora of SCI patients and other neurogenic urinary disorders in relation to individuals without neurogenic disorders may result from the use of antibiotic therapy, use of condom catheters, pH and skin temperature in the area, personal hygiene, or fecal contamination. Pseudomonas colonizes the perineum, in addition to the high pH of the skin of the area appears to contribute positively to the high risk of colonization [78, 79]. The meticulous soap wash of the perineum area only has temporary effects in reducing its colonization by Gram-negative microorganisms, whereas the use of antiseptics, such as chlorhexidine and

infection [75].

**7. Asymptomatic bacteriuria**

of the patients within 3–4 days.

nary tract infection develops [76, 77].

povidone-iodine, has no effect [80, 81].

**8. Skin colonization**

Efforts to eliminate bacteriuria due to the use of permanent or intermittent catheterization have no effect. Intensive or continuous catheterization is a frequent but not documented method of treatment to prevent sedimentation, bacteriuria, urinary tract infection and/or bacteremia. Intravenous administration with neomycin/polymyxin has no effect. Spinal hygiene, perineal wash, and frequent catheter changes have found ineffective methods in reducing urinary tract infection due to catheterization [82]. In addition, it is important for both coating and catheter composition. Prevention of *P. aeruginosa* biofilm formation is observed using silver-coated catheters [83].
