150. Improved Susceptibility of Pseudomonas aeruginosa to Cefepime (CEF) at a Veterans Tertiary Care Hospital, over a 7-Year Period (2011-2017): The Impact of Antibiotic Rotation/Cycling and Reversal of Drug Resistance in P. aeruginosa

Background Background: Pseudomonas aeruginosa continues to be an important cause of nosocomial infections associated with a high morbidity and mortality. Despite the availability of ceftazidime-avibactam (CAZ-AVI) and ceftolozone-tazobactam (CFT-TAZO), CEF continues to be an empiric agent of choice in several institutions. Aim: To evaluate the prevalence and trend in susceptibilities of P. aeruginosa to CEF over a 7-year period, identify possible correlation with the use of CAZ, AZT, PTZ, CIP, and CAR, (DOT/1000 patient days), as a quality improvement (QI) measure for optimizing CEF use, introduce antibiotic cycling as a tool to avoid emergence of drug-resistance in P. aeuriginosa. Methods A retrospective review of antimicrobial susceptibility data of all isolates of P. aeruginosa, (inpatient and outpatient) at the Detroit VAMC pre and post implementation of antibiotic cycling, over a 7-year period (2011-2017) was performed. Susceptibility testing was performed by reference broth micro-dilution methods in a central laboratory. Data analysis was performed using Pearson correlation coefficient score. Being a QI project, clinical data were not reviewed. Results A total of 977 isolates were identified during the study period. (drug usage are in DOT/1000 PD); CAZ and AZT use surged during 2013-14 from 5 to 8 dropping in 2015-17 to < 3; PTZ usage increased to 100 during 2011-14 but dropped to 38 in 2015-17 (drug shortage); CAR use averaged at 10 until 2016 and dropped to 8 in 2017; CIP use dropped by 50% from 30 in 2012 to 15 in 2017; P. aeruginosa susceptible to CEF decreased from 88% in 2012 to 81% in 2014 mirroring the increased use of CEF, AZT, CAZ, and CIP; AG use was very low at < 5. With restrictions on the use of AZT, CAZ, and CIP, from 2014-15, CEF susceptibility increased significantly to 95.5% in 2015. Drug shortage of PTZ in 2015 and increased use of CEF from 2015-17 led to a drop in susceptibility to (82%); P. aeruginosa susceptible to CAR and AG averaged at 88% and 97% respectively (2011-17). However, reintroduction PTZ, resulted in improved susceptibility of P. aeuruginosa to CEF by 40% within a year. Conclusion Judicious antimicrobial use and antibiotic rotation play a significant role in reversing drug resistance in P. aeuruginosa. Disclosures All Authors: No reported disclosures