moxifloxacin + rifabutin + para-aminosalicylic acid + pyrazinamide + ethambutol

This is a combination regimen consisting of five antibiotics—moxifloxacin, rifabutin, para-aminosalicylic acid (PAS), pyrazinamide, and ethambutol—used primarily for the treatment of drug-resistant tuberculosis (TB), including multidrug-resistant TB (MDR-TB). Each component targets Mycobacterium tuberculosis through distinct mechanisms: - **Moxifloxacin** is a fluoroquinolone that inhibits bacterial DNA gyrase and topoisomerase IV, enzymes essential for DNA replication and repair[3][4]. - **Rifabutin** is a rifamycin antibiotic that inhibits bacterial DNA-dependent RNA polymerase, suppressing RNA synthesis. - **Para-aminosalicylic acid** acts as an antimetabolite interfering with folic acid synthesis in mycobacteria. - **Pyrazinamide** is converted by mycobacterial pyrazinamidase to its active form, pyrazinoic acid; it disrupts membrane transport and energy production under acidic conditions within macrophages where M. tuberculosis resides[6][7][8][10]. - **Ethambutol** inhibits arabinosyl transferases involved in cell wall biosynthesis. This combination aims to maximize bactericidal activity while minimizing resistance development by attacking the pathogen at multiple metabolic points. It is typically reserved for cases where first-line agents are ineffective or not tolerated.