Faculty mentor/PI email address
carabetta@rowan.edu
Keywords
antibiotic resistance, bacteriophages, infections, resensitization, Acinetobacter baumannii
Date of Presentation
5-6-2026 12:00 AM
Poster Abstract
Introduction:
Antibiotic resistance poses a major global health threat, particularly with multidrug-resistant (MDR) pathogens such as Acinetobacter baumannii, which exhibits resistance to multiple antibiotic classes, including carbapenems.1 As conventional treatments become less effective, alternative therapies such as bacteriophage therapy are gaining attention. Bacteriophages offer targeted antibacterial activity and may enhance antibiotic efficacy or resensitize resistant strains. This study investigates the synergistic effects of bacteriophage ΦCO03 combined with antibiotics against MDR A. baumannii.
Methods:
Clinical isolates (M20, M5) of A. baumannii were cultured in LB broth at 37°C. Bacteriophage ΦCO03 was isolated and purified using plaque assays. Synergy between phage and antibiotics (notably Imipenem) was evaluated using checkerboard assays, with bacterial growth measured via OD₆₀₀. Fractional inhibitory concentration (FIC) indices were calculated to assess interaction effects. Growth curve assays were performed over 16 hours to confirm sustained antibacterial activity.
Results:
Checkerboard assays demonstrated strong synergy between ΦCO03 and Imipenem, with FIC values frequently < 0.05, indicating enhanced antimicrobial activity. The minimum inhibitory concentration (MIC) of Imipenem decreased significantly in the presence of phage, suggesting bacterial resensitization. Growth curve analysis showed that monotherapy (phage or antibiotic alone) resulted in initial suppression followed by regrowth, whereas combination therapy achieved sustained inhibition of bacterial proliferation.
Discussion:
These findings highlight the potential of bacteriophage-antibiotic combination therapy as an effective strategy against MDR A. baumannii. By targeting bacterial virulence mechanisms and reducing resistance, phage therapy may restore antibiotic susceptibility while preserving the microbiome. This approach represents a promising direction for combating antibiotic-resistant infections and warrants further investigation in broader clinical settings.
References
-
Howard A, O'Donoghue M, Feeney A, Sleator RD. Acinetobacter baumannii: an emerging opportunistic pathogen. Virulence. 2012 May 1;3(3):243‑50. doi:10.4161/viru.19700. PMID:22546906.
Disciplines
Bacterial Infections and Mycoses | Chemicals and Drugs | Medicine and Health Sciences
Resensitization of clinical isolates of MDR-Acinetobacter baumannii to antibiotics using bacteriophage therapy
Introduction:
Antibiotic resistance poses a major global health threat, particularly with multidrug-resistant (MDR) pathogens such as Acinetobacter baumannii, which exhibits resistance to multiple antibiotic classes, including carbapenems.1 As conventional treatments become less effective, alternative therapies such as bacteriophage therapy are gaining attention. Bacteriophages offer targeted antibacterial activity and may enhance antibiotic efficacy or resensitize resistant strains. This study investigates the synergistic effects of bacteriophage ΦCO03 combined with antibiotics against MDR A. baumannii.
Methods:
Clinical isolates (M20, M5) of A. baumannii were cultured in LB broth at 37°C. Bacteriophage ΦCO03 was isolated and purified using plaque assays. Synergy between phage and antibiotics (notably Imipenem) was evaluated using checkerboard assays, with bacterial growth measured via OD₆₀₀. Fractional inhibitory concentration (FIC) indices were calculated to assess interaction effects. Growth curve assays were performed over 16 hours to confirm sustained antibacterial activity.
Results:
Checkerboard assays demonstrated strong synergy between ΦCO03 and Imipenem, with FIC values frequently < 0.05, indicating enhanced antimicrobial activity. The minimum inhibitory concentration (MIC) of Imipenem decreased significantly in the presence of phage, suggesting bacterial resensitization. Growth curve analysis showed that monotherapy (phage or antibiotic alone) resulted in initial suppression followed by regrowth, whereas combination therapy achieved sustained inhibition of bacterial proliferation.
Discussion:
These findings highlight the potential of bacteriophage-antibiotic combination therapy as an effective strategy against MDR A. baumannii. By targeting bacterial virulence mechanisms and reducing resistance, phage therapy may restore antibiotic susceptibility while preserving the microbiome. This approach represents a promising direction for combating antibiotic-resistant infections and warrants further investigation in broader clinical settings.
References
-
Howard A, O'Donoghue M, Feeney A, Sleator RD. Acinetobacter baumannii: an emerging opportunistic pathogen. Virulence. 2012 May 1;3(3):243‑50. doi:10.4161/viru.19700. PMID:22546906.