Pseudomonas aeruginosa (PAE) is intrinsically resistant to numerous classes of antimicrobials such as tetracycline and β-lactam antibiotics. More epidemiological surveillance studies on the antimicrobial susceptibility profiles of PAE are needed to generate clinically significant data and better guided therapeutic options. We describe and analyze in a retrospective study the epidemiologic trends of 1827 Pseudomonas spp. isolates (83.5% PAE, 16.4% Pseudomonas sp., and 0.2% Pseudomonas putida) from various clinical specimens with their resistance patterns to antimicrobial consumption at a tertiary medical center in Lebanon between January 2010 and December 2018. We report a significant drop in the incidence of PAE from sputum (p-value = 0.05), whereas bloodstream infection isolation density showed no trend over the study period. We also registered a minimal but statistically significant drop in resistance of Pseudomonas to certain antibiotics and a decrease in the consumption of antipseudomonal antibiotics (p-value < 0.001). Only 61 PAE isolates from a total of 1827 Pseudomonas cultures (3.33%) were difficult to treat, of which only one was a bacteremia. Interestingly, we found that the carbapenem susceptibility of Pseudomonas was unaffected by the decrease in their consumption. These results augur that antimicrobial pressure may not be the sole contributor to resistance emergence. Finally, antimicrobial stewardship seems to have a positive impact on nosocomial epidemiology.

Background The multiple classical benefits of reducing antimicrobial consumption extend beyond the impact on rates of antimicrobial resistance and infections to include a cost-saving effect of 100,000$-300,000$ per intervention as estimated by the CDC. However, the recent introduction of novel antimicrobial molecules with a high price tag and the fall in the prices of older agents presents a substantial challenge in maintaining cost-effectiveness. Methods We retrieved from the antimicrobial stewardship program(ASP) database the consumption of the Gram-negative broad-spectrum antibacterial agents (GNBS): imipenem, meropenem, ertapenem, piperacillin-tazobactam, amikacin, colistin, ceftazidime, ceftolozane-tazobactam and cefepime from January 2015-August 2019 at Saint George Hospital(SGH), a 333-bed tertiary care center in Lebanon. The yearly cost of all antibacterials consumed during this period were obtained from SGH billing records. GNBS consumption was calculated as Daily Defined Doses (DDD)/1000 Patient Days(PD) per WHO guidelines. Results The carbapenem consumption significantly dropped from a peak of 205 DDD/1000PD in 2015 to 33 DDD/1000PD in 2019. This drop was not accompanied by an increase in the consumption of other GNBS. The total use of GNBS dropped by 54% from 288 DDD/1000PD in 2015 to 132 DDD/1000PD by August 2019. Currently, SGH serves a yearly average of 82,000 patient-days. Hence, this reduction in total GNBS consumption corresponds to 12,792 fewer daily defined doses of antimicrobial therapy per year. The average annual cost of all antibacterials at SGH is 1,100,000 $ (U.S. Dollars), ranging from 955679 $ to 1340109 $ for the period 2015–2019. (Table 1) Consumption of Gram-negative Broad-Spectrum Antimicrobial Agents and Cost of Antibiotics at Saint George Hospital, Lebanon Conclusion The striking decrease in GNBS consumption, namely carbapenems, was not mirrored with a reduction of total antibacterial cost. Although novel antimicrobials carry great potential, they come at a significant increase in overall cost. Modeling ASP interventions solely around cost-effectiveness will limit the better placement of these new agents in institutional therapeutic guidelines. Strict continuous analysis of consumption, antimicrobial resistance, and cost within an ASP provides a proactive and vigilant approach to navigate through the complexity of difficult to treat bacterial infections. Disclosures All Authors: No reported disclosures