ABSTRACT
OBJECTIVE:To investigate synergistic effect of carbapenems combined with fosfomycin(FOS)on carbapenems-re-sistant Pseudomonas aeruginosa isolates from urinary tract infections in vitro. METHODS:The minimum inhibitory concentration was detected using agar double dilution method. The fractional inhibitory concentration index was determined by checkerboard meth-od. The effect of carbapenems combined with FOS on biofilm of P. aeruginosa isolates was determined using 96 crystal violet stain-ing. RESULTS:12 strains of carbapenem-resistant P. aeruginosa isolates were highly sensitive to FOS and amikacin,and were com-pletely resistant to imipenem and meropenem. The combination of imipenem with FOS could induce a synergistic effect on 4 strains (33.3%);meropenem combined with FOS could induce a synergistic effect on 5 strains(41.7%);no antagonistic effect of carbap-enems combined with FOS appeared. FOS combined with carbapenems could inhibit the biofilm of carbapenems-resistant P. aerugi-nosa(P<0.05 or P<0.01). CONCLUSIONS:The combination of carbapenems with FOS possesses in vitro synergistic antibacteri-al effect on part of carbapenems-resistant P. aeruginosa isolates,the mechanism of which may be associated with inhibiting the bio-film.