What Infections Is Tigecycline Approved For?
Tigecycline, a glycylcycline antibiotic, is FDA-approved for complicated skin and skin structure infections (cSSSI), complicated intra-abdominal infections (cIAI), and community-acquired bacterial pneumonia (CABP) in adults and children over 8 years.[1] It targets multidrug-resistant pathogens like Acinetobacter baumannii, Stenotrophomonas maltophilia, and certain Enterobacteriaceae where other options fail.
Why Is Tigecycline Effective Against Resistant Bacteria?
Tigecycline overcomes common resistance mechanisms, such as efflux pumps and ribosomal protection, that limit tetracyclines. It has broad-spectrum activity against Gram-positive (e.g., MRSA, VRE), Gram-negative (e.g., ESBL-producing E. coli, Klebsiella), anaerobes, and some atypicals. MIC90 values are low (≤2 mcg/mL) for many resistant strains, outperforming standard tetracyclines.[2][3]
How Does Tigecycline Compare to Other Antibiotics?
| Infection Type | Tigecycline Advantage | Common Alternatives | Notes |
|---------------|-----------------------|---------------------|-------|
| cSSSI with MRSA | High susceptibility (>95%) | Vancomycin, linezolid | Better tissue penetration |
| cIAI with resistant Gram-negatives | Covers anaerobes + Acinetobacter | Piperacillin-tazobactam, carbapenems | Avoid in P. aeruginosa (inactive) |
| CABP | Active vs. Legionella, atypicals | Levofloxacin, ceftriaxone | Inferior mortality vs. comparators in trials |
Tigecycline succeeds where beta-lactams or quinolones fail due to resistance, but meta-analyses show higher all-cause mortality (1.28 OR) from inadequate dosing against severe infections.[4]
When Is Tigecycline Less Effective or Riskier?
Pseudomonas aeruginosa, Proteus spp., and Burkholderia are intrinsically resistant. FDA warnings highlight increased mortality risk in ventilator-associated pneumonia (VAP) and bloodstream infections—use only as salvage therapy.[1] Nausea (26%) and vomiting (18%) limit tolerability; static bacteriostatic action delays clearance in high-burden infections.
Clinical Trial Data on Effectiveness
Phase 3 trials (e.g., TEST program) showed non-inferiority to imipenem in cIAI (86-91% cure) and vancomycin in cSSSI (83-92% cure).[5] Post-approval studies confirm efficacy against CRAB (carbapenem-resistant Acinetobacter), with 70-80% success in compassionate use, but overall survival lags in sepsis.[3]
[1]: FDA Label for Tygacil
[2]: Clinical Microbiology Reviews - Tigecycline Spectrum
[3]: Antimicrobial Agents and Chemotherapy - Activity vs. Resistant Pathogens
[4]: JAMA Meta-Analysis on Mortality
[5]: New England Journal of Medicine - Tigecycline Trials