Adverse effects of open indwelling urethral catheterization in clinically normal male cats
Lees, G.E.; Osborne, C.A.; Stevens, J.B.; Ward, G.E.
American Journal of Veterinary Research 42(5): 825-833
1981
ISSN/ISBN: 0002-9645 PMID: 7258801 Document Number: 175894
Effects of open indwelling urethral catheterization for 1, 3 or 5 days were evaluated in clinically normal male cats. During 5 days of catheterization, influences of ampicillin or polyionic fluid therapy (or both) were also evaluated. Commercially manufactured catheters used were too short to reach the bladder lumen of most adult male cats and did not provide constant urine drainage. Although only 1 catheter extended into the bladder lumen, bacteriuria was induced in 20 of 36 catheterized cats. Morphologic changes in the urethras of catheterized cats developed in 2 phases. A mild-to-moderate urethritis and variable loss of mucosa occurred first without bacteriuria. In cats with bacteriuria, this change was followed by severe suppurative urethritis. Bacterial cystitis was found in 8 cats with catheter-induced bacteriuria. Although cystitis sometimes developed during 3 days of catheterization, the association between microscopic bladder abnormalities and bacteriuria was significant (P < 0.05) only for cats catheterized for 5 days. The interval in which bacterial colonization of the bladder occurred most frequently in untreated cats was between 1-3 days of indwelling catheteterization. After 1 day of catheterization, 2 of 6 cats had bacteriuria, but evidence of cystitis was not found. After 3 and 5 days of catheterization, 5 of 6 cats had bacteriuria. Degrees of bacteriuria and severity of cystitis did not increase between the 3rd and 5th day of catheterization. Catheter-induced bacteriuria and cystitis were most severe in cats with diuresis produced by fluid therapy. Cats given ampicillin developed catheter-induced bacteriuria less frequently than did cats that were not given the antibiotic. Administration of ampicillin to cats given fluid therapy reduced the degree of bacteriuria. Cystitis was less severe in bacteriuric cats given ampicillin. Although generally beneficial, ampicillin therapy did not prevent catheter-induced bacteriuria in 4 of 12 cats. Bacteria isolated from these cats were highly resistant to ampicillin and tended to have less in vitro susceptibility to other antimicrobial agents. Urine concentration was an important factor influencing degrees of bacteriuria and types of bacteria found in catheterized cats. Bacterial numbers were substantially higher in dilute urine samples from cats given fluids than in urine samples from untreated cats. Most bacteria isolated from concentrated urine samples were gram-positive cocci, whereas isolates from diluted urine samples were mainly gram-negative bacilli. These effects may have been related to urine osmolality. Adverse effects are caused by open indwelling urethral catheterization of male cats. In addition to predisposing cats to bacterial urinary tract infection, catheters had direct effects on surrounding urinary tract tissues.