Activity of ciprofloxacin and azithromycin on biofilms produced in vitro by Haemophilus influenzae

Background It is recognized that Haemophilus influenzae isolated from patients with otitis media forms biofilms both in vitro and in vivo, suggesting that biofilm formation in vivo might play an important role in the pathogenesis and chronicity of otitis media, but the effect of antibiotics on biofi...

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Bibliographic Details
Published in:Chinese medical journal 2009-06, Vol.122 (11), p.1305-1310
Main Authors: Wang, Dong, Wang, Ying, Liu, You-ning
Format: Article
Language:English
Subjects:
Anti-Bacterial Agents - pharmacology
Azithromycin - pharmacology
Biofilms - drug effects
Ciprofloxacin - pharmacology
Haemophilus influenzae - drug effects
Haemophilus influenzae - isolation & purification
Humans
Lung Diseases, Obstructive - microbiology
Microbial Sensitivity Tests
Microscopy, Electron, Scanning
体外研究
慢性阻塞性肺疾病
最低抑菌浓度
流感嗜血杆菌
环丙沙星
生物膜形成
生物被膜形成
阿奇霉素
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Summary:Background It is recognized that Haemophilus influenzae isolated from patients with otitis media forms biofilms both in vitro and in vivo, suggesting that biofilm formation in vivo might play an important role in the pathogenesis and chronicity of otitis media, but the effect of antibiotics on biofilm has not been well studied. We investigated the impact of ciprofloxacin and azithromycin on bacterial biofilms formed by Haemophilus influenzae in vitro in this study. Methods Eleven strains of Haemophilus influenzae were isolated from sputum specimens collected from patients with acute exacerbation of chronic obstructive pulmonary diseases. Formation of bacterial biofUm was examined by crystal violet assay and a scanning electron microscope. Alterations of biofilms were measured under varying concentrations of azithromycin and ciprofloxacin. Results Striking differences were observed among strains with regard to the ability to form biofilm. Typical membrane-like structure formed by bacterial cells and extracellular matrix was detected. Initial biofilm synthesis was inhibited by azithromycin and ciprofloxacin at concentrations higher than two-fold minimal inhibitory concentration. Disruption of mature biofilms could be achieved at relatively higher concentration, and ciprofloxacin displayed more powerful activity. Conclusions Haemophilus influenzae is capable of forming biofilm in vitro. Sufficient dosage might control early formation of biofilms. Ciprofloxacin exerts better effects on breakdown of biofilm than azithromycin at conventional concentration in clinics.
ISSN:0366-6999
2542-5641
DOI:10.3760/cma.j.issn.0366-6999.2009.11.013