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128 Urinary Tract Infections 1191

Classification of Urinary Tract Uncomplicated UTI
VetBooks.ir Infections Uncomplicated UTI occurs in patients where no under-

lying structural, neurologic, or functional abnormalities
Asymptomatic Bacteriuria
mechanisms are compromised (e.g., CKD, hyperadreno-
Bacteriuria is expected in patients with UTI, but may also exist. A UTI becomes complicated when host defense
be observed in healthy dogs and cats if the urine sample has corticism, DM, cystolithiasis, USMI). In addition, UTIs
been contaminated with normal flora and/or pathogens from are often considered complicated if they occur in cats,
the distal urethra/urogenital tract (voided sample or during male dogs, and intact female dogs, or if they involve the
urethral catheterization) or if the sample contacts a con- kidneys or prostate.
taminated surface (e.g., cage floor, examination table). It is
important to differentiate urine contamination from a UTI Recurrent or Reinfection
since the former does not need to be treated. Certain organ-
isms are known to be commensal within the lower urinary Recurrent UTIs can be defined as either relapses or rein-
tract (Table 128.1). There is, however, overlap between fections. A relapse is an infection caused by the same
normal flora and potential pathogens. Contamination can bacteria that caused the original infection, and usually
be ruled out by repeating a urinalysis with urine obtained occurs within days of cessation of treatment. Relapses
via cystocentesis or by performing a quantitative urine are most frequently associated with ineffective antimi-
culture on a voided or catheterized sample. Depending on crobial treatment. This may be due to improper antibi-
the method of urine collection, the number of bacterial otic usage (inappropriate selection, dose, duration, or
colony‐forming units (cfu)/mL of urine will vary between poor owner compliance), emergence of drug‐resistant
contamination and UTI (Table 128.2). pathogens, or failure to eliminate predisposing causes

Table 128.1 Commensal bacterial genera in the urogenital tract of dogs

Genus Distal urethra of males Prepuce Vagina
Acinetobacter + +
Bacteroides +
Bacillus + +
Citrobacter +
Corynebacterium + + +
Enterococcus +
Enterobacter +
Escherichia + + +
Flavobacterium + + +
Haemophilus + + +
Klebsiella + + +
Micrococcus +
Moraxella + +
Mycoplasma + + +
Neisseria +
Pasteurella + +
Proteus + +
Pseudomonas +
Staphylococcus + + +
Streptococcus + + +
Ureaplasma + + +
Source: Barsanti JA. Genitourinary infections. In: Greene CE, ed. Infectious Diseases of the Dog and Cat, 3rd edn. St Louis, MO: Saunders, 2006,
pp. 935–61. Reproduced with permission of Elsevier.