Evaluation of Biofilm Formations of ESKAPE Group Bacteria Isolated from Clinical Samples: Experience with Different Methods

Introduction:The "ESKAPE" group of bacteria is a group of pathogens that poses a global health threat due to their ability to escape the biocidal effects of antibiotics.This group includes Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.This study aimed to determine the biofilm-forming activities of ESKAPE group bacteria from different clinical specimens using two different methodologies and to compare the results of these two approaches. Materials and Methods: In cultures obtained from various clinical specimens collected from patients in Sivas Cumhuriyet UniversityFaculty of Medicine Practice and Research Hospital services and intensive care units, 27 isolates of E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and 26 isolates of Enterobacter spp.were identified.The biofilm production capacities of these microorganisms were assessed using the Congo red agar method and the microtiter plate assay.Statistical analyses were conducted using the McNemar test and Cohen's kappa test. Results:No concordance was observed between the methods in S. aureus, A. baumannii, and P. aeruginosa isolates.In A. baumannii and P. aeruginosa isolates, the microtiter plate assay appears to be more sensitive than other methods.Using this method, biofilm formation was detected at a higher frequency.For E. faecium and K. pneumoniae, a moderate level of concordance was observed between the methods, whereas for Enterobacter spp., both methods demonstrated perfect agreement.The p-values determined for S. aureus, E. faecium, A. baumannii, P. aeruginosa, K. pneumoniae, and Enterobacter spp.were found to be 0.023, 0.025, <0.001, <0.001, and 0.366, respectively.The corresponding kappa values were calculated as -0.068, 0.501, 0, 0.13, 0.375, and 1. Conclusion:Since different methods used for biofilm detection may yield varying results, it is of paramount importance to select the most appropriate research method.This study demonstrated the consistency of the methods in biofilm research.It showed that the microtiter plate method provides more consistent results, especially in biofilm detection in non-fermenting bacteria such as P. aeruginosa and A. baumannii.