Synergistic Effect of Bacteriophage vB_KpnS_Pey and Antibiotic Combinations against Clinical Carbapenem-Resistant Klebsiella pneumoniae Isolates.
8 affiliations
- 1Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran.
- 2Herbal and Traditional Medicines Research Center, Institute of Pharmaceutical Sciences, Kerman University of Medical Sciences, Kerman, Iran.
- 3Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran.
- 4Medical Mycology and Bacteriology Research Center, Kerman University of Medical Sciences, Kerman, Iran.
- 5Department of Medical Microbiology (Bacteriology and Virology), Afzalipour School of Medicine, Kerman, Iran.
- 6Department of Biology, University of Aveiro, Aveiro, Portugal.
- 7Department of Medical Microbiology (Bacteriology and Virology), Afzalipour School of Medicine, Kerman, Iran. [email protected].
- 8Department of Medical Microbiology (Bacteriology and Virology), Afzalipour School of Medicine, Kerman, Iran. [email protected].
Abstract
Background
The global rise of antimicrobial resistance, particularly among carbapenem-resistant Klebsiella pneumoniae (CRKP), presents a serious therapeutic challenge. This study aimed to isolate and characterize a bacteriophage effective against prophage-free CRKP and to evaluate its potential synergistic effects with ciprofloxacin, meropenem, gentamicin, and colistin.Materials and methods
A total of 30 non-duplicate clinical blaNDM-positive CRKP isolates were collected from hospitalized patients in Kerman, Iran. Prophage-free isolates were identified using mitomycin C induction assays. A bacteriophage was isolated from hospital wastewater using enrichment and double-layer agar methods. Phage morphology was identified by transmission electron microscopy (TEM). Host range and efficiency of plating (EOP) were determined using spot assays. The optimal multiplicity of infection (MOI) was assessed by optical density at 600 nm (OD₆₀₀), and phage replication dynamics, including latent period and burst size, were evaluated using a one-step growth curve. Antibiotic susceptibility profiles and minimum inhibitory concentrations (MICs) for ciprofloxacin, meropenem, gentamicin, and colistin were determined by disk diffusion and broth microdilution. Phage-time-kill experiments were used to evaluate antibiotic interactions.Results
TEM revealed that phage vB_KpnS_Pey is a member of the class Caudoviricetes, with an icosahedral head and a long, non-contractile tail. This phage produced clear, halo-form plaques and exhibited lytic activity against 13.3% of CRKP isolates. It showed high EOP against most susceptible strains, a latent period of approximately 30 minutes, and a burst size of 315 plaque-forming units (PFU) per infected cell. The optimal MOI was determined to be 1,000 PFU/colony-forming unit. Combination assays demonstrated phage-antibiotic synergy between vB_KpnS_Pey and subinhibitory concentrations of ciprofloxacin and meropenem, resulting in enhanced bacterial clearance in time-kill experiments. No synergistic effect was observed with gentamicin and colistin.Conclusion
These findings highlight the therapeutic potential of phage vB_KpnS_Pey, particularly when combined with ciprofloxacin and meropenem, as an alternative or combined strategy for treating infections caused by CRKP. Further research is required to fully understand the bacteriophage's mechanisms of action and its associated limitations.
Related
- Genome-wide transposon screening uncovers phage resistance mechanisms and bidirectional effects on antibiotic susceptibility in carbapenem-resistant Klebsiella pneumoniae
- Closely related ST11 Klebsiella pneumoniae isolates with transient attenuation and re-emergence of carbapenem resistance during prolonged hospitalization: a case report
- Capsule types driving carbapenem-resistant Klebsiella pneumoniae in Pakistan are largely absent from the phage literature
- PBT2 potentiates carbapenem antibiotics against diverse Klebsiella pneumoniae strains
- Phenotypic Characterization and Preliminary In Vivo Evaluation of a Locally Isolated Klebsiella pneumoniae Bacteriophage.
BibTeX
@article{farmehr2026synergistic,
title = {{Synergistic Effect of Bacteriophage vB_KpnS_Pey and Antibiotic Combinations against Clinical Carbapenem-Resistant Klebsiella pneumoniae Isolates.}},
author = {Parva Farmehr and Salehe Sabouri and Roya Ahmadrajabi and Saereh Mohammadpour and Hossein Hosseini-Nave and Sanaz Rastegar},
journal = {Infection \& chemotherapy},
year = {2026},
month = sep,
doi = {10.3947/ic.2025.0156},
url = {https://europepmc.org/article/MED/42847627},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Synergistic Effect of Bacteriophage vB_KpnS_Pey and Antibiotic Combinations against Clinical Carbapenem-Resistant Klebsiella pneumoniae Isolates.
AU - Parva Farmehr
AU - Salehe Sabouri
AU - Roya Ahmadrajabi
AU - Saereh Mohammadpour
AU - Hossein Hosseini-Nave
AU - Sanaz Rastegar
PY - 2026
DA - 2026/09/01
JO - Infection & chemotherapy
DO - 10.3947/ic.2025.0156
UR - https://europepmc.org/article/MED/42847627
AB - Background The global rise of antimicrobial resistance, particularly among carbapenem-resistant Klebsiella pneumoniae (CRKP), presents a serious therapeutic challenge. This study aimed to isolate and characterize a bacteriophage effective against prophage-free CRKP and to evaluate its potential synergistic effects with ciprofloxacin, meropenem, gentamicin, and colistin.Materials and methods A total of 30 non-duplicate clinical blaNDM-positive CRKP isolates were collected from hospitalized patients in Kerman, Iran. Prophage-free isolates were identified using mitomycin C induction assays. A bacteriophage was isolated from hospital wastewater using enrichment and double-layer agar methods. Phage morphology was identified by transmission electron microscopy (TEM). Host range and efficiency of plating (EOP) were determined using spot assays. The optimal multiplicity of infection (MOI) was assessed by optical density at 600 nm (OD₆₀₀), and phage replication dynamics, including latent period and burst size, were evaluated using a one-step growth curve. Antibiotic susceptibility profiles and minimum inhibitory concentrations (MICs) for ciprofloxacin, meropenem, gentamicin, and colistin were determined by disk diffusion and broth microdilution. Phage-time-kill experiments were used to evaluate antibiotic interactions.Results TEM revealed that phage vB_KpnS_Pey is a member of the class Caudoviricetes, with an icosahedral head and a long, non-contractile tail. This phage produced clear, halo-form plaques and exhibited lytic activity against 13.3% of CRKP isolates. It showed high EOP against most susceptible strains, a latent period of approximately 30 minutes, and a burst size of 315 plaque-forming units (PFU) per infected cell. The optimal MOI was determined to be 1,000 PFU/colony-forming unit. Combination assays demonstrated phage-antibiotic synergy between vB_KpnS_Pey and subinhibitory concentrations of ciprofloxacin and meropenem, resulting in enhanced bacterial clearance in time-kill experiments. No synergistic effect was observed with gentamicin and colistin.Conclusion These findings highlight the therapeutic potential of phage vB_KpnS_Pey, particularly when combined with ciprofloxacin and meropenem, as an alternative or combined strategy for treating infections caused by CRKP. Further research is required to fully understand the bacteriophage's mechanisms of action and its associated limitations.
SN - 2093-2340
SN - 2092-6448
ER -