Biofilm Formation and its Effects on Ciprofloxacin Sensitivity in Mixed Gram Negative Bacteria Cultures
Project no. 21368 · Status: Kapanmış · 2019
Summary
Biofilm structures are formed by the attachment of microorganisms on biotic and abiotic surfaces, their proliferation, and their living in the matrix they form. In this study, it was aimed to investigate the changes in biofilm levels formed by gram-negative microorganisms together and its effects on ciprofloxacin (CIP) sensitivity. The susceptibility of Escherichia coli ATCC 29998, Klebsiella pneumoniae ATCC 13883 and Pseudomonas aeruginosa ATCC 27853 strains were investigated by microdilution and disk diffusion method. Biofilm forming properties were tested in microplates by the crystal violet method, individually for each strain and by preparing double / triple mixed suspensions. CIP sensitivity of the culture mixes prepared for biofilm study was also tested. Minimum inhibition concentration (MIC) values were found to be 0.008; 0.016 and 0.250 mg/L for E. coli, K. pneumoniae and P. aeruginosa, respectively. According to the disc (5µg/disk) diffusion test, zone diameters were above 30 mm for all three bacteria. MIC values were determined as 0.016 mg/L in mixed culture of E. coli - K. pneumoniae, and 0.250 mg/L in combination of P. aeruginosa with two other bacteria and mixed culture of three bacteria. Bacteria formed strong biofilms under standard conditions when they were single species and in double / triple mixtures. When ciprofloxacin was added, a weak or no biofilm was observed on the MIC and above, and a strong biofilm was detected at values below the MIC. In conclusion, this study, which contains important data on biofilm formation and reduction of sensitivity to ciprofloxacin, which is a major problem especially in hospitals and intensive care units, is thought to be a guide for clinicians in combating biofilm-related infections that cause a long, costly and difficult treatment process for patients. This research was supported by Ege University Scientific Research Committee as Undergraduate Student Participated Research Project (Project No: TLP-2019-21368). Keywords: Biofilm; mixed bacterial culture; ciprofloxacin.