Related Experiment Video
Updated: Oct 9, 2026
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Effects of pentoxifylline on in vivo leukocyte function and clearance of group B streptococci from preterm rabbit
M P Mah1, E E Aeberhard, M B Gilliam
1Department of Pediatrics, School of Medicine, University of California, Los Angeles.
Insights
Pentoxifylline enhanced group B streptococci inactivation in preterm rabbit lungs, despite reducing inflammatory markers. This suggests pentoxifylline may aid newborns with streptococcal pneumonia.
Area of Science:
- Neonatal immunology
- Pharmacology
- Infectious disease
Background:
- Group B streptococci (GBS) pose a significant threat to premature infants.
- Effective treatments for GBS infections in neonates are crucial.
- Pentoxifylline is a phosphodiesterase inhibitor with immunomodulatory properties.
Purpose of the Study:
- To evaluate pentoxifylline's efficacy in clearing GBS from the lungs of premature rabbits.
- To investigate the mechanisms of GBS clearance and pentoxifylline's pharmacodynamics.
- To assess the anti-inflammatory effects of pentoxifylline in this model.
Main Methods:
- A randomized, controlled animal trial was conducted using 123 preterm New Zealand rabbits.
- Rabbits were infected with GBS aerosols and treated with pentoxifylline or placebo.
- Lung GBS burden, leukocyte activity, and inflammatory markers were quantified.
Main Results:
- Pentoxifylline treatment significantly reduced GBS proliferation in the lungs at 24 hours.
- No significant differences were observed in leukocyte numbers or phagocytic activity.
- Pentoxifylline lowered lysozyme and tumor necrosis factor levels in bronchoalveolar lavage fluid.
Conclusions:
- Pentoxifylline enhances GBS inactivation in preterm rabbit lungs, likely through an anti-inflammatory mechanism.
- Therapeutic drug levels were achieved in blood and lung tissue.
- Pentoxifylline shows potential as an adjunctive therapy for neonatal GBS pneumonia.
Objectives:
Pentoxifylline was evaluated for its ability to enhance inactivation of group B streptococci in lungs of prematurely born rabbits. Mechanisms associated with intrapulmonary streptococcal clearance and the pharmacodynamics of pentoxifylline were also investigated.
Design:
Randomized, controlled animal trial.
Setting:
University research laboratory.
Subjects:
A total of 123 New Zealand rabbits were delivered prematurely by cesarean section and were used for clearance studies. Twenty-three preterm pups were additionally utilized to study the pharmacodynamics of pentoxifylline.
Interventions:
Preterm rabbits were infected with group B streptococcal aerosols and given intraperitoneal injections of either pentoxifylline (25, 12.5, and 12.5 mg/kg) or placebo at 0, 6, and 12 hrs after infection.
Measurements And Main Results:
At 0, 4, and 24 hrs, the numbers of streptococci were determined in the left lung, while the right lung underwent bronchoalveolar lavage to quantify intra-alveolar leukocytes, phagocytosis of inhaled bacteria, and concentrations of lysozyme and tumor necrosis factor. In a separate experiment, blood and bronchoalveolar fluid from infected animals were analyzed for pentoxifylline content. Streptococcal proliferation was less in pentoxifylline-treated animals than in controls at 24 hrs (p < .01). Pulmonary macrophages and polymorphonuclear leukocytes recovered from bronchoalveolar lavage fluid did not differ in numbers or phagocytic activity. Pentoxifylline-treated animals had lower levels of lysozyme (p < .02) and tumor necrosis factor (p < .005) in bronchoalveolar lavage fluid compared with placebo-treated pups. Therapeutic levels of pentoxifylline were achieved in blood and bronchoalveolar lavage fluid.
Conclusions:
Despite lowering lysozyme and tumor necrosis factor content in epithelial lining fluid, pentoxifylline improves the inactivation of group B streptococci in preterm rabbit lungs. These findings suggest that increased group B streptococcal clearance was coincident with an anti-inflammatory effect due to pentoxifylline. We conclude pentoxifylline may be clinically useful as an adjunctive therapy for group B streptococcal pneumonia in newborns.
More Related Videos
09:17A Robust Pneumonia Model in Immunocompetent Rodents to Evaluate Antibacterial Efficacy against S. pneumoniae, H. influenzae, K. pneumoniae, P. aeruginosa or A. baumannii
Published on: January 2, 2017
09:26Antibiotic Efficacy Testing in an Ex vivo Model of Pseudomonas aeruginosa and Staphylococcus aureus Biofilms in the Cystic Fibrosis Lung
Published on: January 22, 2021