linezolid + aztreonam

**Linezolid + aztreonam** is a combination of two antibiotics, used together primarily for the broad-spectrum empiric treatment of severe infections. **Linezolid** is a synthetic oxazolidinone-class antibiotic that inhibits bacterial protein synthesis by binding to the 23S rRNA of the 50S ribosomal subunit, preventing the formation of the functional 70S initiation complex. This mechanism is effective against multidrug-resistant gram-positive organisms, including MRSA, VRE, and penicillin-resistant Streptococcus pneumoniae[1][2][3][6]. **Aztreonam** is a monobactam beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, providing potent activity against aerobic gram-negative bacteria, including Pseudomonas aeruginosa. The combination is sometimes used in critical infections where both gram-positive and gram-negative coverage is required. Pharmacokinetic studies show no significant interaction between the two drugs when co-administered[3][5][7], although in vitro data suggest that linezolid may attenuate the bactericidal activity of aztreonam against some E. coli strains and may influence resistance development[4]. Both drugs are available as individual products but may be administered together as part of hospital protocols for severe, mixed infections.