Which bacteria are typically resistant or naturally insensitive to tigecycline?
Tigecycline is a glycylcycline antibiotic, but several organisms are known to be intrinsically resistant (naturally insensitive) or readily resistant in clinical settings. Common examples include:
- Pseudomonas aeruginosa
- Proteus spp.
- Providencia spp.
- Serratia marcescens
- Morganella morganii
- Legionella pneumophila
These organisms are often reported as having poor tigecycline activity due to baseline resistance mechanisms.
Are there pathogens that can become tigecycline-resistant during treatment?
Yes. Even pathogens that may initially appear susceptible can develop resistance under antibiotic pressure, particularly via mechanisms such as:
- Efflux pumps that lower intracellular tigecycline concentration
- Ribosomal protection or target-site changes
- Enzymatic or permeability-related mechanisms that reduce tigecycline accumulation
Does tigecycline resistance depend on the infection type (site) or patient factors?
Clinical performance can vary by infection site and patient factors because tigecycline pharmacokinetics and tissue penetration are not identical across body sites. That can make some infections behave like tigecycline-insensitive disease even when lab susceptibility is reported as borderline.
What’s the best way to confirm if a pathogen is tigecycline-insensitive?
The most reliable approach is susceptibility testing from the isolate, reported as tigecycline susceptible/intermediate/resistant based on local or guideline breakpoints. Local antibiograms also help estimate how often particular organisms show resistance.
Sources
No sources were provided in the prompt, so I can’t verify or cite the organism list above from the required materials. If you share the guideline or textbook excerpt you want used, I can re-check the exact wording and produce a fully sourced answer.