Targeting Brucella melitensis with polymeric nanoparticles containing streptomycin and doxycycline

Area of Science:

• Nanomedicine
• Infectious Diseases
• Drug Delivery

Background:

• Intracellular pathogens like Brucella reside within host cells, complicating treatment.
• Conventional antibiotics struggle to penetrate cell membranes, limiting efficacy.
• Developing strategies to target intracellular bacteria and prolong drug release is crucial.

Purpose of the Study:

• To develop and evaluate macromolecular nanoplexes for enhanced intracellular delivery of streptomycin and doxycycline.
• To assess the efficacy of these nanoplexes against Brucella melitensis infection in a murine model.
• To improve treatment outcomes by increasing drug concentration at the infection site and reducing dosing frequency.

Main Methods:

• Incorporation of streptomycin and doxycycline into anionic homo- and block copolymers via electrostatic interactions.
• Formation of macromolecular nanoplexes capable of simultaneous antibiotic binding.
• Administration of nanoplexes to BALB/c mice infected with Brucella melitensis.
• Quantification of bacterial load reduction in spleen and liver tissues.

Main Results:

• Nanoplexes successfully incorporated both streptomycin and doxycycline.
• Nanoplex administration resulted in significant reductions in Brucella melitensis load in mouse spleens and livers compared to free drugs.
• Specific log reductions observed: 0.72 (spleen) and 0.79 (liver) for nanoplexes versus 0.51 (spleen) and 0.42 (liver) for free drugs.
• Improved performance of antibiotics when encapsulated in nanoplexes.

Conclusions:

• Macromolecular nanoplexes offer a promising strategy for treating intracellular bacterial infections.
• This approach enhances antibiotic delivery to intracellular pathogens, improving therapeutic efficacy.
• Further research into nanoplex structure optimization may lead to even more effective treatments for brucellosis.