Objective: Describe antimicrobial therapy and aerobic bacteriologic culture patterns in canine intensive care unit (ICU) patients in a university hospital.
Design: Retrospective descriptive.
Setting: A tertiary university referral hospital.
Animals: Seventy-four canine ICU patients.
Interventions: From January to June 2006 patient antimicrobial use, minimum inhibitory concentration (MIC) results, and clinical data were recorded. Appropriate antimicrobial use was analyzed relative to the time of culture submission and MIC results.
Measurements and main results: Mean+/-SD age was 7.2+/-4.2 years. Median (range) length of ICU and hospital stays were 3 days (1-25 d) and 4 days (1-27 d), respectively. A total of 106 cultures were submitted; 47 of 106 (44%) cultures were positive for 70 isolates, including Escherichia coli (16/70 [23%]), Staphylococcus intermedius (7/70 [10%]), and Acinetobacter baumannii (5/70 [7%]). A multidrug resistant pattern occurred in 19 of 70 (27%) isolates, and was significantly more likely after 48 hours of hospitalization (P<0.001). Antimicrobials were administered before culture submission in 42 of 74 dogs (57%) and included enrofloxacin (23/42 [55%]), ampicillin (20/42 [48%]), and amoxicillin/clavulanic acid (8/42 [19%]). Antimicrobial choices were appropriate 19% of the time. While pending culture results, antimicrobials were administered to 67 of 72 (94%) dogs remaining alive, and were appropriate 75% of the time. The most common antimicrobials administered while awaiting culture results were ampicillin (52/67 [78%]), enrofloxacin (49/67 [73%]), and amikacin (9/67 [13%]). Post-MIC antimicrobials were appropriate 89% of the time. Of 45 dogs remaining alive, 17 (37%) continued to receive antimicrobials despite negative cultures.
Conclusions: Antimicrobial use was extensive in this patient population, but when available, MIC results were used to guide antimicrobial therapy. Many patients with negative cultures continued to receive antimicrobial therapy. Multidrug resistant bacteria were more likely in cultures taken after 48 hours of hospitalization.