Authors : VinodKumar C.S, Ananya V Swamy, Shreshta Shamanur, Arpitha Venkatareddy, V.L Jayasimha, Sriman Narayan Reddy, Susan Jyothica Dsouza, Srinivasa H
DOI : 10.18231/j.ijirm.2022.029
Volume : 7
Issue : 3
Year : 2022
Page No : 130-137
Introduction: Multidrug-resistant strains of Acinetobacter baumannii, a significant hospital pathogen, have developed resistance to virtually all available antibiotics. Carbapenems antibiotics are among the most commonly used antibiotics against Acinetobacter infections, but they can be rendered ineffective by the metallo-beta-lactamase enzyme. In this study, bacteriophage isolated against blaSPM-1 producing Acinetobacter baumannii was evaluated for its therapeutic potential in the rabbit pneumonia model.
Materials and Methods: Acinetobacter baumannii was isolated from the sputum and was speciated as per the standard microbiological techniques. Bacteriophage specific for blaSPM-1 producing Acinetobacter baumannii from the sewage water. Pneumonia was introduced in the rabbits as per Esposito Pennington method and efficacy of the bacteriophage in resolving pneumonia was evaluated. For in-vivo experiments, five groups of rabbits were used including infection-free, phage control, bacteria-infected control, and the other two groups infected with Acinetobacter baumannii and treated either with an antibiotic, colistin (2.5 mg/kg, twice a day intraperitoneally) or Acinetobacter phage (3×109 PFU/mL, given once through
nebulizer). The experimental animals were monitored for 72 hours for mortality, and the surviving rabbits were killed for bacteriological and histopathological analysis.
Results: In the infected group, pneumonia was developed within 48 hours, and 6/10 animals were dead after 72 hours. All the animals in the antibiotic group survived but showed signs of pneumonia, and there was up to 4 log CFU/g±0.24 reduction in the bacterial count. In phage treated group, all the animals survived at the end of 72 hours and all the animals were healthy with no signs of pneumonia.
Conclusions: The experiment showed new insights into the application of bacteriophage through nebulization, a non-invasive method of phage delivery to rescue rabbits from pneumonia caused by blaSPM-1-producing Acinetobacter baumannii.
Keywords: Rabbit models, bla SPM1, Acinetobacter baumannii, Nebulization, Phage therapy, Pneumonia.