2477. Antimicrobial Resistance Patterns of Enterobacteriaceae and Pseudomonas Aeruginosa from Colombian Clinical Isolates. 2017–2018

Abstract Background The Study for Monitoring Antimicrobial Resistance Trends (SMART) is a worldwide initiative to monitor in vitro susceptibility of clinical Gram-negative isolates to several antimicrobial agents. Surveillance initiatives are essential to provide real-world evidence to support local guidelines development. Colombia has participated since 2012 with isolates from complicated intrabdominal infections (cIAI), complicated urinary tract infections (cUTI) and respiratory tract infections (RTI). This study describes resistant patterns of Escherichia coli (Eco), Klebsiella pneumoniae (Kpn) and Pseudomonas aeruginosa (Pae) clinical isolates collected in Colombian hospitals in a 2 years period (2017–2018). Methods Isolates from patients with cIAI, cUTI and RTI were collected. Identification confirmation was done in central laboratory. Minimum inhibitory concentrations (MIC) were performed by broth microdilution and interpreted according to 2018 CLSI guidelines, same criteria for Extended-spectrum β-lactamase (ESBL) classification. The antimicrobial activity was evaluated for aztreonam (ATM), ceftolozane/tazobactam (C/T), ceftazidime (CAZ), colistin (COL), ertapenem (ETP), cefepime (FEP), imipenem (IMP), meropenem (MEM) and piperacillin–tazobactam (TZP). Results During 2017–2018, 1492 isolates were collected. The main organism was Eco (51%) followed by Kpn (29%) and Pae (20%). In vitro susceptibility activity is presented in Table 1. COL, C/T, ETP, MEM and IPM exhibited over 95% susceptibility in Eco. ESBL prevalence was 18% for Eco (53/314) and 22% for Kpn (36/165). COL and C/T were the most active agents against Pae isolates. For Kpn, MIC50/90 values were: MEM (0.12 / 8), C/T (0.5 / 8) and for TZP (8 / > 64), meanwhile for Pae were MEM (0.5 / 32), C/T (0.5 / 32) and for TZP (8 / > 64). Conclusion Continued antimicrobial resistance surveillance initiatives are critical to guide the empiric treatments decision in a multidrug resistance era. This study shows that Ceftolozane/Tazobactam, MEM and COL have the best susceptibility profile against Eco, Kpn and Pae of cIAI, cUTI and RTI cases in Colombia. The C/T susceptibility rates and low MIC distribution provide evidence to support its use as a non-carbapenem therapeutic alternative for Gram-negative infections. Disclosures All authors: No reported disclosures.