TITLE:
Comparative Study of the Mutant Prevention Concentrations of Sulfamethoxazole-Trimethoprim Alone and in Combination with Levofloxacin against Stenotrophomonas maltophilia
AUTHORS:
Xihai Xu, Xi Chen, Nian Sun, Jun Yin, Jiabin Li
KEYWORDS:
Stenotrophomonas maltophilia, Mutant Prevention Concentration, Sulfamethoxazole-Trimethoprim, Levofloxacin
JOURNAL NAME:
Advances in Infectious Diseases,
Vol.7 No.2,
June
22,
2017
ABSTRACT: Objectives: To determine the mutant prevention
concentration (MPC) of sulfamethoxazole-trimethoprim (SXT) alone and in combination with levofloxacin (LVX) against Stenotrophomonas
maltophilia (S. maltophilia)
and to determine if the combination may decrease the emergence of resistant mutants. Methods: The MPC
with 20 S. maltophilia strains which were both susceptible to SXT and
LVX were determined by inhibiting visible growth among 1010 CFU on
four agar plates after 72 hours incubation at 37°C. Results: All
except two strains (18/20) showed a mutant prevention concentration ≥ 152/8 μg/mL for SXT and the range of the mutant prevention
concentration for the SXT in combination with LVX is 9.5/0.5~608/32 μg/mL, which demonstrates
at least 2 fold reduction except one strain. There was a significant difference
(P Conclusions: The MPC/MIC values were
narrowed for SXT by combining with LVX against the S maltophilia. The
combination may decrease the enrichment of mutant bacterial populations. Much
study is needed to verify whether the using of drug combinations may restrict
or even block the selection of S. maltophilia mutants.