Investigation of the biofilm structure of P. aeruginosa strains in linezolid medium

The aim of this study was to determine the biofilm formation abilities and degree of P. aeruginosa isolates in the resistant linezolid medium. The susceptibility of 40 isolated P. aeruginosa to various antibiotics was tested by the disk diffusion method. According to the test results, the isolates were resistant to kanamycin, oxacillin, teicoplanin, rifampicin, streptomycin, and linezolid. However, gentamicin (97.5%), amikacin (87.5%), cefoperazone/sulbactam (75%) and netilmicin (57.5%) were also found to be susceptible. According to the biofilm test results performed with congo red agar, crystal violet and the safranin method, biofilm formation was observed in 70%, 75%, and 72.5% of the isolates, respectively. As a result, the minimum inhibitory concentrations (MIC) of P. aeruginosa isolates in planktonic structure were determined as 64 mg/L after treatment with linezolid. Biofilm inhibitor concentration (BIC) of 128 mg/L was determined in the medium with linezolid for P. aeruginosa isolates. Biofilm-forming P. aeruginosa have become more resistant to linezolid than the planktonic form. The mechanisms of resistance in antibiotic therapy of infections caused by P. aeruginosa need to be examined in more detail. Today, with the developing technology, it is necessary to develop new antibacterial drugs that can affect the biofilm structure and resistance mechanism of P. aeruginosa.