aztreonam + clindamycin

Aztreonam + clindamycin is a combination of two antibiotics used primarily for the treatment of polymicrobial infections, especially in settings where both aerobic gram-negative and anaerobic or certain gram-positive bacteria are likely pathogens. Aztreonam is a monobactam antibiotic with specific activity against aerobic gram-negative bacilli, including Enterobacteriaceae and Pseudomonas species. It works by inhibiting bacterial cell wall synthesis through binding to penicillin-binding protein 3 (PBP3), leading to cell lysis and death. Clindamycin is a lincosamide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, providing coverage against anaerobic bacteria as well as some streptococci and staphylococci. This combination has been studied for use in gynecologic infections (such as endometritis, pelvic cellulitis), lower respiratory tract infections caused by mixed flora, intra-abdominal infections, and perioperative prophylaxis in surgeries at risk for both aerobic gram-negative and anaerobic infection[1][3][5][10]. The rationale for combining these agents is their complementary spectra—aztreonam covers aerobic gram-negatives while clindamycin targets anaerobes and some gram-positives.