Evaluation of different perioperative antibiotic therapy durations in bitches with open-cervix pyometra

In the current scenario, antibiotic therapy for the treatment of infectious processes such as pyometra is a matter of concern in veterinary medicine. The indiscriminate use of antibiotics and the consequent emergence of bacterial resistance have led to therapeutic protocols that often show reduced or absent efficacy. Since ovariohysterectomy eliminates the source of infection, the use of pre-, intra-, and postoperative antibiotic therapy has been questioned by many researchers. Prospective studies based on the restricted use of such medications may contribute to the development of guidelines for the optimal treatment of pyometra and, indirectly, improve the long-term efficacy of antibiotics. The present study aimed to compare the clinical and hematological outcomes of bitches with open-cervix pyometra undergoing ovariohysterectomy associated with different durations of antibiotic therapy, as well as to monitor the course of the infectious process during postoperative recovery. A total of 14 bitches were allocated into three groups: Group 1 (n = 5) - bitches undergoing ovariohysterectomy and receiving antibiotic therapy intraoperatively and for 1 day postoperatively; Group 3 (n = 6) - bitches undergoing ovariohysterectomy and receiving antibiotic therapy intraoperatively and for the first 3 postoperative days; and Group 7 (n = 3) - bitches undergoing ovariohysterectomy and receiving antibiotic therapy intraoperatively and for 7 postoperative days. Clinical evaluation, including anamnesis and general and specific physical examinations, was performed during the preoperative and postoperative periods. All groups showed postoperative clinical recovery and reduction of inflammatory hematological parameters over time. Despite baseline differences in leukocyte and segmented neutrophil counts among groups, similar hematological profiles were observed seven days after surgery, with comparable short-term clinical and hematological outcomes among the different antibiotic protocols. The results of the present study suggest that shorter durations of postoperative antibiotic therapy may be associated with comparable short-term outcomes in clinically stable bitches with pyometra undergoing ovariohysterectomy. However, these findings should be interpreted with caution due to the small sample size and limited follow-up period.