Phenotypic Profiling of Biofilm Development and Efflux Pump Mechanisms in Multidrug-Resistant (MDR) Klebsiella pneumoniae

Klebsiella pneumoniae causes diverse healthcare- and community-associated infections, frequently affecting patients with indwelling medical devices. Its ability to form biofilms and activate efflux pumps enhances antibiotic resistance. These two mechanisms work synergistically, accelerating the emergence of multidrug-resistant K. pneumoniae strains..This study investigated the antibiotic resistance patterns of Klebsiella pneumoniae isolates in relation to their potential for biofilm formation and efflux pump activity. A total of Sixteen (16) K. pneumoniae isolates were obtained from the Department of Microbiology, University of Lagos, Lagos State. Confirmation of K. pneumoniae was conducted through culture, microscopy, and biochemical assays. Antibiotic susceptibility testing was performed using six routinely prescribed antibiotics. Phenotypic assessment of efflux pump activity and biofilm formation was conducted using the ethidium bromide (EtBr) cartwheel assay and Congo red agar method, respectively. The results indicated that all isolates were multidrug-resistant, exhibiting high resistance to Ofloxacin (12, 75.00%), Cephalexin (9, 56.25%), and Ampicillin (8, 50.00%). Four 4(25%)isolates demonstrated biofilm-forming ability, while only two 2(12.5%) isolates exhibited efflux pump activity. The results highlight biofilm formation and efflux pump activity as key virulence mechanisms contributing to the pathogenicity and multidrug resistance of K. pneumoniae, highlighting the need for targeted therapeutic strategies to overcome these resistance mechanisms.