Abstract
Background
This study aims to distinguish hypervirulent Klebsiella pneumoniae (hvKp) from its classical counterpart (cKp) by utilizing Potassium tellurite agar (PTA) and the String test, with a focus on biofilm formation. The magA gene is investigated as a potential biomarker for identifying robust biofilm-producing hvKp strains, highlighting the significance of this research in addressing the global health threat posed by hvKp.
Methods
From January to December 2022, 102 Klebsiella pneumoniae isolates were collected from patients at AVMC&H, Puducherry. The identification of hvKp was performed using both phenotypic (PTA and the String test) and genotypic methods, including antimicrobial susceptibility testing and 96-well plate biofilm assays. The expression of hvKp-associated genes (rmpA, rmpA2, and magA) was assessed through conventional PCR.
Results
Phenotypic tests identified 28 isolates as hvKp via PTA and 23 through the String test. All rmpA-positive isolates were PTA positive, with 8 also positive in the String test. For rmpA2-positive isolates, 14 were positive in both tests. Fifteen isolates expressed the magA gene, with all showing positivity in the String test and 14 in PTA. Biofilm assays categorized isolates into non-biofilm producers (1.02%), moderate (36.73%), and strong biofilm producers (62.24%). Strong biofilm producers showed resistance to multiple antibiotics.
Conclusions
PTA and the String test are effective in identifying hvKp, with the magA gene serving as a promising biomarker for strong biofilm-producing isolates. The study reveals a concerning trend of antibiotic resistance among biofilm-producing isolates, indicating the potential for hvKp to evolve into a pan-drug-resistant superbug. This underscores the need for heightened global attention to mitigate the threats posed by hvKp.