Comprehensive Analysis of Biofilm Formation in Intensive Care Unit Isolates: Biofilm-associated Genes (mrkA, fimA, bap, and ompA) of Klebsiella pneumoniae and Acinetobacter baumannii

• Published in: Biomedical and Biotechnology Research Journal Vol. 9; no. 3; pp. 335 - 344
• Main Authors: Anees, T. M. Mohammed, Shetty, A. Veena, Mehandale, Sripada G, Karnaker, Vimal Kumar, Deekshit, Vijaya Kumar
• Format: Journal Article
• Language: English
• Published: India Wolters Kluwer - Medknow 01.07.2025; Medknow Publications and Media Pvt. Ltd
• Edition: 2
• Subjects: Analysis; Antibiotics; Bacterial pneumonia; Beta lactamases; Drug resistance in microorganisms; Gene expression; Genes; Health aspects; Hospital patients; Original Article; Pneumonia; India; mrkA gene; multidrug resistance; ompA gene; intensive care unit; Biofilm formation
• ISSN: 2588-9834; 2588-9842
• DOI: 10.4103/bbrj.bbrj_214_25

Background: Multidrug-resistant (MDR) Klebsiella pneumoniae and Acinetobacter baumannii nosocomial infections provide a challenge to intensive care unit (ICU) care because of their capacity to build biofilms, which increases antibiotic resistance and persistence, especially in immunocompromised patients undergoing invasive procedures. Methods: This work investigated the involvement of 47 clinical isolates of K. pneumoniae and A. baumannii from ICU patients at a tertiary care hospital in antimicrobial resistance (AMR) by looking at biofilm formation dynamics at 24, 48, and 72 h as well as biofilm-associated gene expression. The Vitek system and Double Disc Synergy Test were used to assess AMR, including carbapenemase and extended-spectrum beta-lactamase (ESBL) synthesis, as per CLSI guidelines. Strong, moderate, weak, and non-biofilm production were measured using the 96-well microtiter plate method. The polymerase chain reaction (PCR) detection of biofilm-related genes (mrkA, fimA in K. pneumoniae; bap, ompA in A. baumannii) was followed by quantitative-PCR analysis of mrkA and ompA expression in specific isolates. Results: With 64% (16/25) of K. pneumoniae and 95.45% (21/22) of A. baumannii exhibiting resistance, 78.72% (37/47) of the isolates were MDR. Carbapenem resistance was found in 66% (31/47) and ESBL production in 80.85% (38/47) of cases. 63.63% (14/22) of A. baumannii and 60% (15/25) of K. pneumoniae formed biofilms. Ninety-five percent of A. baumannii had bap and ompA, 72% had fimA, and all K. pneumoniae had mrkA. The expression of mrkA and ompA was enhanced in strong biofilm makers, indicating their function in persistence and AMR. Conclusion: This study underscores how important biofilm development is for MDR and the persistence of A. baumannii and K. pneumoniae in ICUs. K. pneumoniae biofilms peaked at 48 h, according to time-dependent research, whereas A. baumannii biofilms formed earlier. Strong biofilm development in K. pneumoniae was associated with elevated mrkA expression. Improving ICU patient outcomes requires targeted treatments to break down biofilms and improve infection management.