Study on the Antibacterial Effects of Queous Extract of Phryma leptostachya L.var. asiatica Hara Combined with Antibiotics in vitro against ESBLs-producing E.coli

In order to study the antibacterial effects in vitro of the aqueous extracts of Phryma leptostachya L.var.asiatica Hara combined with antibiotics against ESBLs-producing E.coli,we used broth micro-dilution method and micro-dilution checker-board technique to measure the minimal inhibitory concentrations (MIC) and the fractional inhibitory concentrations index (FICI) of Phryma leptostachya L.var.asiatica Hara and antibiotics.The results showed that the FICI of Phryma leptostachya L.var.asiatica Hara combined with ceftriaxone sodium,ceftazidime,cefotaxime sodium,ceftiofur sodium,amoxicillin,amikacin,azithromycin,fosfomycin,colistin,sulfamonomethoxine,rifampicin,ciprofloxacin,norfloxacin,levofloxacin,mequindox,lincomycin were 0.75,0.75,1.00,0.75,0.53,0.51,0.75,4.5,4.5,4.5,4.5 and 2.5,respectively.The results of the tests indicated that the aqueous extracts of Phryma leptostachya L.var.asiatica Hara combining with ceftriaxone sodium,ceftazidime,cefotaxime sodium,ceftiofur sodium,amoxicillin,amikacin,azithromycin,fosfomycin,colistin,sulfamonomethoxine and rifampicin showed additive effect;Combining with ciprofloxacin,norfloxacin,levofloxacin,mequindox and lincomycin had the antagonistic effect.