Abstract
Background: Pantoea species are emerging opportunistic pathogens that are increasingly implicated in nosocomial infections, particularly among immunocompromised individuals. Understanding their virulence mechanisms, specifically biofilm formation and associated genetic determinants, is essential for addressing these resilient infections. Objectives: This study aimed to isolate clinical Pantoea spp., evaluate their biofilm-forming capacity, and detect the prevalence of virulence-associated genes (zapA, fimH, and mrkD). Methodology: Pantoea spp. were isolated from 220 clinical samples and identified using biochemical tests and the VITEK 2 system. Biofilm formation was assessed phenotypically using Congo Red Agar (CRA) and quantified using a Microtiter Plate (MTP) assay. The zapA, fimH, and mrkD genes were detected using Polymerase Chain Reaction (PCR). Results: Thirty-two Pantoea spp. isolates were identified in this study. The MTP assay revealed that 100% of the isolates were strong biofilm producers. The CRA method demonstrated that 56.2% of the isolates produced a strong slime layer. Gelatinase activity was observed in 62% of the isolates. PCR detected zapA, fimH, and mrkD in 37.5%, 56.2%, and 25% of the isolates, respectively. Conclusion: Clinical Pantoea isolates exhibit a robust capacity for biofilm formation, which correlates with the presence of key virulence genes in the biofilm. The synergistic action of adhesion and protease genes likely facilitates persistent colonization and immune evasion, highlighting their pathogenic potential in healthcare settings and underscoring the need for targeted therapeutic strategies against biofilm-mediated infection.