Aztreonam is a synthetic monobactam antibiotic designed to treat infections caused by Gram-negative bacteria. It is especially effective against pathogens like Pseudomonas aeruginosa and various members of the Enterobacteriaceae family. Its mechanism of action involves disrupting bacterial cell wall synthesis, which ultimately leads to the death of the bacteria.
How Aztreonam Works
Aztreonam targets bacterial cell walls by binding to specific penicillin-binding proteins (PBPs). This inhibits the synthesis of peptidoglycan, an essential component of the bacterial wall, causing the bacteria to weaken and rupture. This antibiotic is bactericidal—it kills bacteria rather than merely inhibiting their growth.
Antibacterial Spectrum
Effective Against:
Aztreonam is highly effective against aerobic Gram-negative organisms, including:
- Pseudomonas aeruginosa
- Escherichia coli (E. coli)
- Klebsiella species
- Proteus species
- Enterobacter species
- Serratia species
Not Effective Against:
- Gram-positive bacteria
- Anaerobic bacteria
For broader coverage, aztreonam is sometimes used in combination with other antibiotics that target different bacterial classes.
Available Forms & Administration
Aztreonam can be administered in two main forms:
- Intravenous (IV): Used for systemic and serious infections
- Inhalation (e.g., Cayston®): Specifically used in cystic fibrosis patients with chronic Pseudomonas lung infections
The choice of formulation depends on the infection type and the patient’s condition.
Clinical Applications
Aztreonam is used in several types of infections where Gram-negative bacteria are involved:
- Respiratory Tract Infections: Especially beneficial for cystic fibrosis patients with chronic lung infections
- Urinary Tract Infections (UTIs): Caused by susceptible Gram-negative organisms
- Intra-abdominal Infections: Typically combined with agents effective against anaerobic bacteria
- Skin and Soft Tissue Infections: Due to Gram-negative pathogens
- Septicemia: In cases where Gram-negative organisms are the suspected cause
Key Benefits of Aztreonam
- Low cross-reactivity with other beta-lactam antibiotics, making it safer for patients with penicillin or cephalosporin allergies
- Minimal disruption to healthy gut flora, reducing the likelihood of Clostridioides difficile (C. diff) infections
- Available in inhaled form for targeted treatment in lung conditions
Possible Side Effects
Aztreonam is generally well-tolerated. However, some individuals may experience:
- Rashes or skin irritation
- Nausea, vomiting, or diarrhea
- Pain or swelling at the injection site (IV)
- Bronchospasms or cough (inhaled form)
Always report any adverse effects to your healthcare provider.
Resistance Considerations
While aztreonam is effective against many Gram-negative pathogens, bacterial resistance may develop through:
- Beta-lactamase enzyme production
- Altered penicillin-binding proteins
To ensure effectiveness, use should be guided by culture and sensitivity testing.
Conclusion
Aztreonam is a valuable antibiotic option for treating serious Gram-negative bacterial infections, especially in patients with beta-lactam allergies or those with cystic fibrosis. As with all antibiotics, its use should be based on proper diagnosis and under the guidance of a healthcare professional.
Consult your doctor or infectious disease specialist before starting any antibiotic treatment, including aztreonam.