Which bacteria are known to develop resistance to tigecycline?
Tigecycline resistance is most often reported in bacteria that already have broad drug-resistance mechanisms, and it typically emerges via three main routes: efflux pumps, target-site changes (especially in the ribosome), and other tetracycline-resistance pathways that can cross-react with tigecycline.
What specific resistance mechanisms are linked to tigecycline resistance?
Mechanisms associated with tigecycline resistance include:
- Efflux pumps that export tigecycline out of the cell.
- Ribosomal protection proteins that reduce tigecycline binding at the ribosome.
- Enzymatic or gene-mediated tetracycline resistance determinants that can confer reduced susceptibility to tigecycline.
Which resistance patterns show up most often in clinical bacteria?
In practice, tigecycline resistance is discussed most frequently for multidrug-resistant Gram-positive and Gram-negative organisms, particularly where tetracycline-class resistance is already present or where efflux-based resistance is common.
Examples of bacteria that are commonly described in tigecycline resistance discussions include:
- Staphylococcus aureus (including resistant hospital strains)
- Enterococcus species
- Enterobacterales (such as Klebsiella pneumoniae and Escherichia coli)
- Acinetobacter baumannii
- Pseudomonas aeruginosa
Do specific genes or proteins matter?
Yes. For tigecycline specifically, resistance is often linked to:
- Tetracycline resistance genes that can extend to tigecycline activity.
- Ribosomal protection and efflux determinants that lower tigecycline’s effective concentration inside bacterial cells.
What if a lab wants to identify tigecycline resistance?
Clinically, resistance is usually identified by susceptibility testing (culture-based antimicrobial susceptibility results), and some settings may use molecular testing to look for known resistance genes when available.
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I can give a more precise list (e.g., specific species plus the named resistance determinants reported for them) if you share whether you mean (1) bacteria with tigecycline non-susceptibility in general, (2) bacteria with documented tigecycline-specific resistance genes, or (3) organisms where tigecycline resistance has been clinically reported in the literature you’re using.