Incidence of antibiotic de-escalation in hospitalized internal medicine patients diagnosed with cystitis or pyelonephritis

Background: Based on internal antibiotic utilization review, ciprofloxacin, ceftriaxone, piperacillin/tazobactam, and cefepime were identified as four of the top ten broad spectrum antibiotics utilized for urinary tract infections (UTIs). The purpose of this study was to evaluate the percentage of patients initiated on the above antibiotics for UTI or pyelonephritis that were then narrowed when culture susceptibilities became available. Secondary objectives include percent of patients meeting McGeer’s criteria to determine appropriateness of antibiotic initiation and time to de-escalated therapy after susceptibility results were available.

Methods:

Medical records were reviewed to obtain patient demographic, antibiotic, and culture data. Patients were included if they were >18 years old, admitted to an internal medicine team, started on empiric therapy with above mentioned empiric antibiotics, and had a positive urine culture with susceptibility results. Patients were excluded if they had a documented functional or anatomical abnormality of the urethra, pregnancy, or confirmed co-infection of another origin. Descriptive statistics were utilized for the primary and secondary endpoints.

Results:

79 patients were included in the study, 55.7% were female with a median age of 67. Most common antibiotic utilized was piperacillin/tazobactam at 40.5% followed by ceftriaxone at 26.6%. 67% of patients had their antibiotics de-escalated in response to susceptibility results, 29% of patients did not have indications for de-escalation, and 5% of patients were identified for potential de-escalation that was not performed. 72.7% of patients with an indwelling catheter had McGeer’s criteria present and 63% of patients without an indwelling catheter had McGeer’s criteria present. 59% had their antibiotics de-escalated in 0-24 hours and 19.6% had their antibiotics de-escalated > 48 hours after susceptibility results received.

Conclusion:

The majority of patient’s antibiotics were tailored to culture susceptibility reports. Proper initiation of treatment for UTI was identified as an area for further education and intervention. Improved timing of antibiotic de-escalation from when susceptibility results were available was also identified as an area of intervention.