In vitro antibacterial activity of triclosan in combination with different antibacterial agents against triclosan-resistant multidrug-resistant Acinetobacter baumannii / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the in vitro antibacterial activity of triclosan combined with different antibacterial agents against triclosan-resistant multidrug-resistant Acinetobacter baumannii ( A. bau-mannii) . Methods A total of 626 A. baumannii strains were collected from the First Affiliated Hospital of Wenzhou Medical University from 2016 to 2017. The sensitivity of these A. baumannii strains to common an-tibiotics was detected by VITEK 2-compact automatical microbiological analyzer and the minimum inhibitory concentrations ( MIC) of triclosan were detected by agar dilution method. Checkerboard method was used to detect the changes in MIC values of triclosan against 16 triclosan-resistant multidrug-resistant A. baumannii strains after it was used in combination with four external ointments, including gentamicin, erythromycin, chloramphenicol and kanamycin, and three common antibiotics of imipenem, meropenem and ciprofloxacin, respectively. Fractional inhibitory concentration index ( FICI) was used to evaluate the joint bacteriostatic effects. Results Among the 626 A. baumannii strains, 17 were resistant to triclosan with a drug resistance rate of 2. 7％ (17/626). These triclosan-resistant strains had high MIC values for ciprofloxacin, imipenem,ceftazidime and other commonly used clinical antibiotic and most of them were multidrug-resistant. After tri-closan was used in combination with seven different antibacterial drugs, the MIC values of all drugs de-creased to various degrees compared with those when they were used alone. Triclosan in combination with gentamicin, chloramphenicol and ciprofloxacin showed synergistic effects on 62. 5％, 56. 25％ and 62. 5％of the 16 strains and additive effects on 37. 5％, 43. 75％ and 37. 5％, respectively. When it was used in combination with erythromycin, kanamycin, imipenem and meropenem, synergistic effects on 37. 5％, 25％, 12. 5％ and 12. 5％, additive effects on 37. 5％, 56. 25％, 62. 5％ and 62. 5％, and indifferent effects on 25％, 18. 75％, 25％ and 25％ of the strains were detected, respectively. No antagonistic effect was found between triclosan and any of the above antibiotics. Conclusions Triclosan combined with genta-micin, chloramphenicol and ciprofloxacin had better in vitro antibacterial effects against the triclosan-resist-ant multidrug-resistant A. baumannii strains in this study with synergistic and additive effects. Some indiffer-ent effects were found between triclosan and kanamycin, erythromycin, imipenem and meropenem, but no antagonistic effects were detected.