1882. Resistance (R) Trends in Gram Negative Bacilli (GNB) to Fluoroquinolones (FQ), [Ciprofloxacin (CIP), Levofloxacin (LEV), Moxifloxacin (MOX)], Trimethoprim-sulfamethoxazole (TMP/SMX) and Nitrofurantoin (NFT) over a 7-year period: Pre- and Post- Implementation of FQ Restriction at a Tertiary Care Veterans Affairs Medical Center (VAMC).
Session: Poster Abstract Session: Antimicrobial Stewardship: Potpourri
Saturday, October 6, 2018
Room: S Poster Hall
  • ID WEEK -2018 QUINOLONES-1.pdf (309.6 kB)
  • Background: Unrestricted use of FQ has been associated with emergence of drug resistance in GNB. Active surveillance measures are essential components of antibiotic stewardship practice. Aim: To evaluate antibiotic utilization, assess the impact of FQ restriction on resistance to FQ, TMP/SMX, and NFT, and identify quality improvement measures to prevent emergence of resistance in GNB.

    Methods: A retrospective records review and comparison of antimicrobial susceptibility data for GNB isolated at the Detroit VAMC over a 7-year period, pre- and post- FQ restriction, implemented in 2013. Susceptibility testing was performed by reference broth micro-dilution methods in a central laboratory. Antibiotic usage data were obtained from pharmacy computer records from 2011-17. Antibiotic use in inpatients was expressed as days of therapy/1000 patient-days (DOT/PD) and as number of prescriptions filled for outpatients. Data were analyzed using Pearson correlation coefficient score.

    Results: In 2016-17, the most common GNB isolated in our institution were E. coli (n=303), Klebsiella pneumoniae (n=100) and P. aeruginosa (n=70). Inpatient: During 2011-12, DOT/1000 PD for CIP, LEV and MOX were 34, 10 and 5 respectively, that dropped to 14, 5 and 3 during 2014-17, post- FQ restriction initiated in 2013. Outpatient: During 2013-17, outpatient CIP and MOX prescriptions decreased from 1936 to 781 and from 478 to 86 respectively; however, prescriptions for LEV, TMP/SMX and NFT increased from 33 to 128, 680 to 1074 and 95 to 322 respectively. Overall: Resistance to CIP, LEV and MOX had increased by 8% in E. coli (14 to 22%) and by 7% in P. aeruginosa (10 to 17%) during 2015-17; FQ-R in K. pneumonia and NFT-R in E coli stayed low at 7% and 2% respectively. Also, isolates of TMP/SMX-resistant E. coli and NFT-resistant K. pneumonia increased from 20- to 27% and 40-51% respectively.


    Use of FQ among outpatients was still high (781 scripts in 2017) despite a 4-year restriction, resulting in high FQ-R in E. coli and P. aeruginosa; a concomitant increase in TMP/SMX and NFT resistance was noted, attributed to a compensatory increased use of these agents during the study period (p<0.05). Reversal of resistance trends may take a few years. Antimicrobial stewardship activities need to be enhanced in both ambulatory and inpatient settings in order to achieve optimal results.

    Suganthini Krishnan Natesan, MD, Medicine, John D. Dingell VA Medical Center/Wayne State University, Detroit, MI and Ryan Kuhn, PharmD, BCPS-AQ ID, John D. Dingell VA Medical Center, Detroit, MI


    S. Krishnan Natesan, None

    R. Kuhn, None

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