Previous Antibiotic Exposure and Antimicrobial Resistance Patterns of spp. and aeruginosa Isolated from Patients with Nosocomial Infections.

Background: The alarming spread of antibiotic-resistant bacteria causing healthcare-associated infections has been extensively reported in recent medical literature.

Aims: To compare trends in antimicrobial consumption and development of resistance among isolates of spp. and that cause hospital infections.

Study Design: Cross-sectional study.

Methods: A study was conducted in a tertiary healthcare institution in central Serbia, during the 7-year period between January 2009 and December 2015. The incidence rate of infections caused by or , as well as their resistance density to commonly used antibiotics, were calculated. Utilization of antibiotics was expressed as the number of defined daily doses per 1000 patient-days.

Results: A statistically significant increase in resistance density in 2015 compared to the first year of observation was noted for , but not for , to third-generation cephalosporins (p=0.008), aminoglycosides (p=0.005), carbapenems (p=0.003), piperacillin/tazobactam (p=0.025), ampicillin/sulbactam (p=0.009) and tigecycline (p=0.048).

Conclusion: Our study showed that there is an association between the resistance density of spp. and utilization of carbapenems, tigecycline and aminoglycosides. A multifaceted intervention is needed to decrease the incidence rate of and hospital infections, as well as their resistance density to available antibiotics.