Antibiotic susceptibility and outer membrane proteins of clinical Xanthomonas maltophilia isolates.

Twenty clinical Xanthomonas maltophilia isolates were studied for their susceptibility to various antibiotics and for their outer membrane protein profiles and compared to Pseudomonas aeruginosa isolates. Among the antibiotics studied, fleroxacin and ciprofloxacin exhibited the greatest activity (MIC90 4 micrograms/ml). All the X. maltophilia isolates exhibited similar outer membrane protein profiles with 40, 23 and 21 major proteins, whereas the outer membrane of P. aeruginosa revealed at least 7 major outer membrane proteins, as is known from the literature. Thus, it is assumed that the outer membrane profile of X. maltophilia contributes to the resistance of this nosocomial pathogen to most antibiotics.