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Bactrim reduces the inflammatory response in a murine model of acute rhinosinusitis
Y S Won1, A Brichta, F Baroody
1Section of Otolaryngology-Head and Neck Surgery, University of Chicago, Illinois, USA.
Objective:
To determine whether treatment with an antibiotic (trimethoprim-sulfamethoxazole) reduced the inflammatory response in a murine form of Streptococcus pneumoniae-induced rhinosinusitis.
Design:
We randomized 18 C57BL/6 mice to either treatment with intraperitoneal trimethoprim-sulfamethoxazole (Bactrim, 30 mg/kg) or no treatment (control). After 2 days, we inoculated all C57BL/6 mice intranasally with a Bactrim-susceptible strain of Streptococcus pneumoniae, ATCC 49619, suspended in Trypticase soy broth. At day 5 after bacterial inoculation, we sacrificed the mice and prepared histopathologic sections of their sinuses after culturing their nasal cavities by lavage.
Setting:
Animal care facility at a tertiary, academic institution.
Methods:
The histopathologic sections of the sinuses were examined in a blind manner for the percent of sinus cavity area occupied by neutrophil clusters, and for the number of neutrophils per square millimeter of sinus mucosa.
Results:
The Bactrim group had a significantly smaller sinus area occupied by neutrophil clusters (1.58% +/- 1.13 vs 4.38% +/- 3.41; P < 0.05), significantly fewer neutrophils infiltrating the mucosa (58.81 +/- 29.63/mm2 vs 105.85 +/- 48.49/mm2; P < 0.05), and significantly less growth of Streptococcus pneumoniae colonies in the intranasal cultures (8 few and 1 moderate vs 3 few, 3 moderate, and 1 many; P = 0.05) compared to the control group.
Conclusion:
In our murine model of acute rhinosinusitis, Bactrim decreased the number of neutrophil clusters in the sinus cavities, the number of neutrophils infiltrating the sinus mucosa, and the growth of Streptococcus pneumoniae. We propose that our murine model can be used for the study of the pathophysiology and treatment of acute rhinosinusitis.
Insights
Trimethoprim-sulfamethoxazole (Bactrim) reduced inflammation and Streptococcus pneumoniae growth in a mouse model of acute rhinosinusitis. This study suggests the model
Area of Science:
- Microbiology
- Immunology
- Pharmacology
Background:
- Bacterial rhinosinusitis is a common condition often treated with antibiotics.
- The inflammatory response plays a key role in the pathophysiology of rhinosinusitis.
- Understanding the efficacy of antibiotics in modulating this response is crucial for effective treatment.
Purpose of the Study:
- To investigate the anti-inflammatory effects of trimethoprim-sulfamethoxazole (Bactrim) in a murine model of Streptococcus pneumoniae-induced rhinosinusitis.
- To evaluate the impact of Bactrim on neutrophil infiltration and bacterial load in the sinuses.
Main Methods:
- Eighteen C57BL/6 mice were randomized into two groups: treatment with trimethoprim-sulfamethoxazole (30 mg/kg) or a control group.
- Mice were intranasally inoculated with Streptococcus pneumoniae (ATCC 49619).
- Histopathological analysis of sinus tissues assessed neutrophil clusters and mucosal infiltration; bacterial cultures quantified Streptococcus pneumoniae growth.
Main Results:
- The Bactrim-treated group showed significantly reduced sinus area occupied by neutrophil clusters (1.58% vs 4.38%, P < 0.05).
- Significantly fewer neutrophils infiltrated the sinus mucosa in the Bactrim group (58.81/mm2 vs 105.85/mm2, P < 0.05).
- Reduced growth of Streptococcus pneumoniae colonies was observed in the intranasal cultures of the treated group (P = 0.05).
Conclusions:
- Trimethoprim-sulfamethoxazole effectively decreased neutrophil infiltration and Streptococcus pneumoniae growth in a murine model of acute rhinosinusitis.
- The study validates a murine model for investigating the pathophysiology and treatment of acute rhinosinusitis.
- These findings support the use of trimethoprim-sulfamethoxazole in managing bacterial rhinosinusitis by reducing inflammation.