508. Gentamicin Non-susceptibility is Associated with Persistence of Carbapenem-Resistant Klebsiella pneumoniae in the Urinary Tract

BACKGROUND: Urinary tract infection (UTI) is the most common clinical manifestation of carbapenem-resistant Klebsiella pneumoniae (CRKp). Persistent CRKp bacteriuria is associated with the spread of CRKp and antibiotic overuse. Risk factors for persistent CRKp bacteriuria are uncertain. METHODS: CRACKLE-1 was a multicenter, prospective study that included 960 patients with at least one carbapenem-resistant Enterobacteriaceae (CRE)-positive culture from December 2011 to June 2016 collected from 18 hospitals encompassing 8 healthcare systems in the Midwestern US and North Carolina. Patients with CRKp bacteriuria who were discharged alive from index hospitalization were included in the current study, and sporadic (single positive CRKp urine culture) and persistent (≥2 CRKp urine cultures during independent hospital admissions occurring at least 2 days apart) cases were compared. Antibiotic susceptibility testing was performed by local laboratories. Amikacin, gentamicin (GENT), and trimethoprim/sulfamethoxazole were included in the analysis based on variance and frequency of testing. The CDC/National Healthcare Safety Network criteria for UTI were used. RESULTS: CRKp was the most common CRE isolate (n = 869, prevalence 91%). In patients with CRKp, 527 had CRKp isolated from the urine (prevalence 61%, 95% CI 0.57, 0.64). Of these, 486 patients, of whom 129 (27%) were diagnosed with a UTI, were discharged alive. Notably, 135/486 (28%) patients with CRKp bacteriuria were readmitted and yielded a second urine culture of CRKp. Most patients with persistent bacteriuria, 99/135 (73%), were asymptomatic at initial admission. Of these patients, 20/99 (20%) were diagnosed with a UTI at second admission. In multivariable analysis, only GENT non-susceptibility was associated with an increased risk (adjusted OR 1.66, 95% CI 1.10–2.49) of persistent bacteriuria. Persistent bacteriuria was independent of GENT treatment during index hospitalization (GENT was used in 15% of patients). CONCLUSION: Bacteriuria with GENT non-susceptible CRKp strains was associated with persistent bacteriuria. As this was independent of GENT treatment, GENT resistance determinants may be co-transmitted along with traits that promote bacterial persistence in CRKp. [Image: see text] DISCLOSURES: All authors: No reported disclosures.