绿脓假单胞菌对环丙沙星和Tienam等8种药物体外交叉耐药研究

绿脓假单孢菌（约１０＾７ｃｆｕ／ｍｌ）接种于含环丙沙星（ＣＰＬＸ）次抑菌浓度肉汤中传代培养，可筛选到以对ＣＰＬＸ耐药的变异株。然而在４倍最小抑菌浓度中，耐药变异株出现的频率低。ＣＰＬＸ耐药变朱对其它氟喹诺酮类药物亦耐药。

Study on cross-resistance between ciprofloxacin and tienam and/or other eight drugs with Pseudomonas aeruginosa in vitro

Selection and growth of ciprofloxacin-resistant variants, which were present in low frequencies at 4 time the minimum inhibitory concentration(MIC), were seen when 107 cfu/ml inocula of Pseudomeonas aeruginosa incubated and transferred with subinhibitory coocentrations of ciprofloxacin. These variants showed cross resistance to other quinolones. In 5 of 17 strains tested, ciprofloxacin selected tienam-resistant variants were also isolated in a similar way.The opposite phenomenon of ciprofloxacin-tienam cross resistance after exposure to tienam was not detedted.None of the ciprofloxacin-resistant variants showed cross resistance to ceftaxidime,cefoperozone,piperacillin, or amikacin.These finding indicate that prevalent and without careful use of ciprofloxacin gives a potential risk of development of resistacne in P. aeruginosa not only to quinolones but also to another useful agent tienam. These results suggested that cliniciansshould pay attention to in-vitro susceptibility testing of antibiotics.