Retrospective evaluation of postoperative antibiotics and identification of predictive factors for preoperative urinary tract infection in cats undergoing perineal urethrostomy

Urethral obstruction in male cats remains prevalent in veterinary medicine, with many experiencing recurrence and several catheterization events prior to perineal urethrostomy. Currently, there is a lack of an established incidence of preoperative urinary tract infection in cats undergoing perineal urethrostomy and clinical consensus on treatment. However, empirical antibiotic use prevails with antimicrobial resistance at the forefront. This study aimed to determine the incidence and identify risk factors for a preoperative urinary tract infection in cats undergoing perineal urethrostomy. An additional intent was to critically evaluate empirical postoperative antibiotic prescription. A medical record search identified cats that underwent perineal urethrostomy. Antibiotic use was recorded. Cats were diagnosed with a preoperative urinary tract infection based on a positive urine culture obtained at initial presentation or time of surgery and concurrent lower urinary tract clinical signs. Potential risk factors of a preoperative urinary tract infection were identified and explored by univariable logistic regression. A total of 141 cats were identified. Seventy cats had a perioperative urine culture performed and 27 cats (39%) were diagnosed with a urinary tract infection. Pyuria ( P =0.04) and bacteriuria ( P =0.01) on urinalysis were associated with a positive urine culture. Antibiotic administration included: 19 cats (27%) preoperatively, 68 cats (97%) perioperatively, 67 cats (96%) postoperatively during hospitalization and 60 cats (86%) discharged with antibiotics. Of the individuals diagnosed with a preoperative urinary tract infection, 11 cats (41%) were discharged with an appropriate postoperative antibiotic, whereas 16 cats (59%) were prescribed an inappropriate antibiotic based on urine culture and susceptibility results. In cats undergoing perineal urethrostomy, the incidence of preoperative urinary tract infection warrants clinical consideration. In this cohort, 39% of cats that had a urine culture performed had a positive result. Given the overlap between clinical signs of urinary tract infection and feline lower urinary tract disease, urine culture may be considered in cats undergoing perineal urethrostomy to facilitate appropriate antibiotic stewardship. Pyuria and bacteriuria were significantly associated with a positive urine culture. Prospective validation of these findings is warranted to determine whether preoperative urinalysis can be used to guide postoperative antibiotic therapy pending culture results.