Investigation of In Vitro Activity of Mecillinam Against Isolates of Enterobacteriaceae

Introduction: Mecillinam is an oral antibiotic with excellent clinical efficacy in the treatment of uncomplicated UTIs. It is a betalactam antibiotic and active against Enterobactericeae but has little activity against Gram positive bacteria. In this study, we aimed to investigate the in vitro activity of mecillinam against Enterobactericeae isolates that were isolated from different clinical specimens. Materials and methods: Identification of the bacterial isolates were tested by conventional methods and Phoenix (Becton Dickinson, USA) and Vitek MS (Biomeriux, France) automated systems. Antimicrobial susceptibility was performed by using the disk diffusion method and Phoenix (Becton Dickinson, USA) and Vitek2 Compakt (Biomeriux, France) autometed systems. Mecillinam susceptibility of the isolates were determined by disc diffusion method by using 10 μg mecillianm disc and interpreted according to the EUCAST criteria. Results: Total of 338 Enterobactericeae (E. coli n=162, Klebsiella spp. n=142, Enterobacter spp. n=18, Proteus spp. n=10, Citrobacter spp. n=4, Salmonella spp. n=2) isolates were tested. Most of the clinical specimens were urinary specimens (n=272, 80.5%). Mecillinam susceptibility was detected as 82.5%. Mecillinam susceptibility for urinary tract isolates was 87.1%. In this study, 57% of imipenem resistant isolates were determined susceptible for mecillinam. Conclusion: In conclusion, Mecillinam could be a good option, especially for urinary tract infections.