Investigation of In Vitro Activity of Colistin and Tygecyclin Against Stenotrophomonas Maltophilia Isolates

Abstract

Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen, causing infections whose management is often problematic due to its inherent resistance to many antibiotics. In this study, we aimed to investigate the antimicrobial susceptibility of colistin and tygecyclin as an alternative treatment options for S. maltophilia infections. A total of 122 S. maltophilia isolates were tested. Minimum inhibitory concentration (MIC) values of colistin and tygecycline were determined by broth microdilution method. Susceptibility of TMP/SMX and levofloxacin (LVX) were determined by disc diffusion method and MIC value of ceftazidime (CAZ) was determined by using E-test. Out of 122 S. maltophilia isolates, 5 (4%) of them were resistant to TMP-SXM. MIC range was 0.125- >512 μg/ml and MIC<inf>50</inf>64 μg/ml, MIC<inf>90</inf>512 μg/ml for colistin. MIC range for tygecyclin was detected as 0.5- >8, MIC<inf>50</inf>2 μg/ml and MIC<inf>90</inf>8 μg/ml. Tygecyclin resistance was detected as 66.4% according to the EUCAST guideline and 13.1% according to the USA-FDA breakpoints. And colistin resistance was determined as 86.9% according to both guidelines. © 2021 Ondokuz Mayis Universitesi. All rights reserved.