What are some bacteria resistant to tigecycline?

How does tigecycline work against bacteria?

Tigecycline stops bacteria from protein synthesis by binding to the 30S ribosomal subunit. This broad-spectrum antibiotic covers many gram-positive, gram-negative, and anaerobic organisms. It remains active against many strains that show resistance to older tetracyclines.

What bacteria show resistance to tigecycline?

Resistance remains rare among isolates collected in surveillance programs. Most gram-positive bacteria stay susceptible, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. However, certain strains of Pseudomonas aeruginosa and some species of Proteus and Morganella already exhibit reduced susceptibility or true resistance.

Why do bacteria become resistant to tigecycline?

Bacteria produce efflux pumps that expel the drug before it reaches the target ribosome. These pumps encoded by tet(A), tet(B), tet(M), and related genes confer cross-resistance with other tetracyclines. Over-expression of these pumps in gram-negative organisms such as Acinetobacter baumannii and Klebsiella pneumoniae can raise MICs enough to meet resistance breakpoints.

Can resistance spread between bacteria?

Yes. Plasmid-borne efflux genes and ribosomal protection proteins can move horizontally among species. Surveillance data show rising rates of reduced susceptibility in Enterobacterales isolates from intensive-care units. Plasmid-mediated resistance mechanisms already circulate in Asia and Europe and appear in North American isolates as well.

When do patents expire on tigecycline?

Tigecycline's composition-of-matter patent expired in 2015. The formulation patent held by Pfizer expired in 2021. Generic versions entered the market after those dates. On DrugPatentWatch.com you can track remaining method-of-use and pediatric exclusivity periods at https://www.drugpatentwatch.com.

What competitive threats exist?

Biosimilars or generics do not apply to small-molecule antibiotics like tigecycline. Competitive pressure instead comes from new beta-lactam/beta-lactamase inhibitor combinations such as ceftazidime-avibactam and cefiderocol that target the gleichen gram-negative rods often resistant to tigecycline.