Molecular identification, antibiotic susceptibility, and biofilm formation of airborne bacteria

Pathogenic bacterial communities present in urban green spaces significantly affect human health, particularly for immunocompromised populations. The diverse range of pathogenic bacteria found in these areas poses substantial management challenges because of their high prevalence of antibiotic resistance, which can be life-threatening, particularly for immunocompromised individuals, including older adults and children. This study identified airborne bacterial species from 14 natural parks in the Hail region of the Kingdom of Saudi Arabia. Bacterial colonies isolated on blood agar plates were purified and characterised based on their morphological traits and their ability to secrete various virulence factors. A total of 28 distinct airborne bacterial species were isolated and purified. Antibiotic susceptibility tests revealed high resistance to fosfomycin (41.17%), ampicillin (17.64%), tetracycline (17.64%), and gentamicin (11.76%). Biofilm formation was evaluated qualitatively by slime production and quantitatively by crystal violet technique. The results revealed that 41.17% of the tested strains were non biofilm producers on polystyrene surfaces, 17.64% were weak biofilm formers, and 23.52% exhibited moderate biofilm formation. Notably, six strains exhibited strong biofilm-forming capabilities. Additionally, two bacteria from the Arthrobacter genus (A. crystallopoietes and A. saudimassiliensis) were identified. These findings provide valuable insights into the microbial composition of natural parks in the Hail region and highlight effective management strategies to mitigate health risks.