Investigation of biofilm production and antibacterial susceptibility in hospital-acquired pneumonia caused by klebsiella and acinetobacter species

Aim: Biofilm structure is formed by the adhesion of microorganisms to each other and to the surface. Biofilm formation has a key role for the formation of infectious diseases. It negatively affects the outcome of illnesses via causing relapse and antibiotic resistance. This study aimed to investigate biofilm-forming characteristics and antibacterial susceptibility of two Ventilator Associated Pneumonia (VAP) pathogens including Acinetobacter spp and Klebsiella spp strains. Method: Acinetobacter spp or Klebsiella spp was isolated in the tracheal secretion samples between October 2019 and June 2021. Patients with Clinical Pulmonary Infection Score (CPIS)> 6 and time of intubation > 48 hours were included. The antibacterial susceptibility of the isolated strains was investigated using E-test and microdilution method. The biofilm-forming capacity of the isolated strains was investigated by String test, Congo Red Agar (CRA) Method, Tube Method (TM) and Tissue Culture Plate Method (TCPM). Results: In the 98 samples included this study, there was no significant relationship between biofilm formation and colistin, meropenem and amikacin susceptibility. Likewise the association between biofilm production and the outcome of VAP was not statistically significant. The sensitivity of the String test is 5.75%, the specificity is 90.91% (p=0.001). The sensitivity of the Congo Red Agar Method is 22.99%, the specificity is 90.91% (p=0.001), and the sensitivity of the Tube Method is 83.91% and specificity of the Tube Method is 0% (p=0.690). Discussion: Microorganisms had high rates of biofilm production and antibiotic resistance in our study. No relationship was found between biofilm formation and clinical outcomes. Keywords: Biofilm, antibiotic resistance, VIP, mortality