Phenotypic Detection and Antimicrobial Resistance Profile of Metallo-β-Lactamase-Producing Klebsiella pneumoniae Clinical Isolates in Tehran, Iran, 2024
Novelty in Biomedicine,
Vol. 14 No. 4 (2026),
13 October 2026
,
Page 198-204
https://doi.org/10.22037/nbm.v14i4.52800
Abstract
Background: Klebsiella pneumoniae is a major cause of healthcare-associated infections, and the emergence of carbapenem-resistant and metallo-β-lactamase (MBL)-producing strains poses a major therapeutic and infection-control challenge. The aim of this study was to detect metallo-β-lactamases (MBLs) and determine the antimicrobial resistance profile of Klebsiella pneumoniae Clinical Isolates.
Materials and Methods: A total of Forty-four non-duplicate consecutive K. pneumoniae isolates were obtained from patients admitted to tertiary care hospitals in Tehran between January 2024 and June 2024. These isolates were cultured from various clinical specimens, including sputum and urine. Antimicrobial susceptibility testing was performed using both disk diffusion (16 disks) and microdilution methods for five antibiotics, imipenem, meropenem, ciprofloxacin, ceftazidime, and colistin, according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Additionally, the combined disk diffusion test (CDDT) was used to confirm the production of metallo-β-lactamases (MBLs).
Results: The lowest rate of resistance was observed against tigecycline (n = 2, 4.6%), and fosfomycin (n = 7, 15.9%). The resistance rates determined by the broth microdilution method were 31.8% for imipenem, 29.6% for meropenem, 68.2% for Ciprofloxacin, 79.5% for ceftazidime, and 15.9% for colistin. The number of isolates with multidrug-resistant (MDR) and extensively drug-resistant (XDR) phenotypes was 28 (63.6%) and 16 (36.4%), respectively. Using the DDST, 34.09% of K. pneumoniae isolates were positive for MBL production.
Conclusion: The high prevalence of multidrug-resistant and extensively drug-resistant Klebsiella pneumoniae isolates, along with significant MBL production, emphasizes the urgent need for antimicrobial stewardship, continuous monitoring, and effective infection control measures.
- Klebsiella pneumoniae
- Antibiotic resistance
- Metallo-beta-Lactamase
- Extensively drug resistance
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