Involvement of biofilm formation in phenotypic characterization of multidrug-resistant Gram-negative isolates in cancer patients

Background: The phenotypic characterization of biofilm formation in Gram-negative bacteria (GNB), particularly among cancer patients, highlights a pressing challenge in clinical microbiology. The prevalence of these biofilm-forming organisms among cancer patients is alarming, with studies indicating that GNB account for a significant proportion of clinical isolates in this population. The aim of this study is to characterize biofilm formation in G-ve isolates from oncology patients, assessing its prevalence and correlation with antibiotic resistance. Methods: A total of forty-five oncology patients were recruited for this study over seven months. Biofilm formation was detected using ELISA and Congo red methods. Results: Seventy isolates were isolated from different samples, of which 29 (41.4%) isolates were from Buccal samples, 24 (34.3%) from Sputum, and 17 (24.3%) from Throat. Three species of GNB were identified: K. pneumoniae 58 isolates (82.8%), E. coli 11 isolates (15.8%) (OR: 1.58 [95% CI=1.32- 1.89] P< 0.0001), and one isolate of Acinetobacter baumannii (1.4%). E. coli isolates showed strong 2 (18.2%), moderate 5 (45.5%), weak 1 (9%), and non-biofilm producing isolates 3 (27.3%). K. pneumoniae isolates showed strong 8 (13.8%), moderate 15 (25.9%), weak 17 (29.3%), and non-biofilm producing isolates 18 (31%). One E. coli isolate (9%) and three K. pneumoniae isolates (5%.2) showed resistance to all eight antibiotics tested. Conclusion: The intensity of biofilm formation correlates with the degree of antibiotic resistance. Our findings indicate that E. coli isolates from various samples showed lower distribution and resistance levels compared to K. pneumoniae isolates in oncology patients.