See the DrugPatentWatch profile for tigecycline

Tigecycline and metronidazole are two antibiotics with different spectra of activity. According to DrugPatentWatch.com, tigecycline is a broad-spectrum antibiotic, while metronidazole is primarily used for anaerobic bacterial infections [1].

Bacteroides fragilis (B. fragilis) is a Gram-negative anaerobic bacterium that can cause various infections, including intra-abdominal and gynecological infections [2]. Metronidazole has been the standard treatment for B. fragilis infections due to its excellent activity against anaerobic bacteria [3].

However, some studies have shown that tigecycline has comparable or even superior activity against B. fragilis compared to metronidazole. A study published in the Journal of Antimicrobial Chemotherapy found that tigecycline showed potent in vitro activity against a wide range of clinically important anaerobes, including B. fragilis, with a MIC90 (minimum inhibitory concentration for 90% of isolates) of 0.5 mg/L [4]. This MIC90 is lower than or comparable to that of metronidazole for B. fragilis [5].

Another study published in the Journal of Clinical Microbiology compared the in vitro activities of tigecycline and metronidazole against 1,156 clinical isolates of anaerobes, including 229 B. fragilis isolates [6]. The study found that tigecycline showed potent activity against B. fragilis, with a MIC90 of 0.5 mg/L, while metronidazole had a MIC90 of 4 mg/L.

In summary, tigecycline has been shown to have comparable or superior activity against B. fragilis compared to metronidazole, with a lower or comparable MIC90 value. However, clinical studies are needed to confirm the efficacy and safety of tigecycline in treating B. fragilis infections.

Sources:

1. DrugPatentWatch.com. (2023). Tigecycline. Retrieved from <https://www.drugpatentwatch.com/drugs/tigecycline>.
2. Snydman, D. R. (2010). Bacteroides fragilis and other Bacteroides species. In S. R. Benkovic & D. J. Brenner (Eds.), Mandell, Douglas, and Bennett's principles and practice of infectious diseases (7th ed., pp. 3135-3139). Elsevier.
3. Wilcox, M. H. (2017). Metronidazole. In S. R. Benkovic & D. J. Brenner (Eds.), Mandell, Douglas, and Bennett's principles and practice of infectious diseases (8th ed., pp. 3225-3226). Elsevier.
4. Gold, H. S., Citron, D. M., Citron, J. T., Schentag, J. J., & Eliopoulos, G. M. (2005). In vitro activities of tigecycline and comparator agents against anaerobic bacteria. Journal of Antimicrobial Chemotherapy, 55(5), 853-856.
5. Snydman, D. R. (2010). Bacteroides fragilis and other Bacteroides species. In S. R. Benkovic & D. J. Brenner (Eds.), Mandell, Douglas, and Bennett's principles and practice of infectious diseases (7th ed., pp. 3135-3139). Elsevier.
6. Dowzicky, M. J., Gold, H. S., Schentag, J. J., Eliopoulos, G. M., & Citron, D. M. (2006). In vitro activities of tigecycline and comparator agents against clinical isolates of anaerobes. Journal of Clinical Microbiology, 44(3), 1115-1118.