Trimethoprim lactic is a bacteriostatic antibiotic and an orally active dihydrofolate reductase inhibitor. Trimethoprim lactic is active against a wide range of Gram-positive and Gram-negative aerobic bacteria. Trimethoprim lactic has the potential for urinary tract infections, Shigellosis and Pneumocystis pneumonia treatment[1][2][3].
Trimethoprim interrupts folate metabolism by inhibition of the activity of dihydrofolase reductase (DHFR), which reduces dihydrofolate to tetrahydrofolate (THF)[1].Trimethoprim causes protein aggregation and induction of main heat shock proteins (Hsps) in E. coli cells, which indicates that Trimethoprim presence leads to protein misfolding. Trimethoprim causes induction of DnaK, DnaJ, GroEL, ClpB, and IbpA/B Hsps. Among these Hsps, IbpA/B are most efficiently induced by Trimethoprim and coaggregates with the insoluble proteins. Upon folate stress, deletion of the delta ibpA/B operon resulted in increased protein aggregation but does not influence cell viability[1].
In intraperitoneal infections in mice, the CD50 values for Trimethoprim alone against H. influenzae, S. pneumoniae, E. coli and N. meningitidis, is 150 mg/kg, 335 mg/kg, 27.5 mg/kg and 8.4 mg/kg, respectively[2].
[1]. Ewa Laskowska, et al. Trimethoprim Induces Heat Shock Proteins and Protein Aggregation in E. Coli Cells. Curr Microbiol. 2003 Oct;47(4):286-9.
[2]. R N Brogden, et al. Trimethoprim: A Review of Its Antibacterial Activity, Pharmacokinetics and Therapeutic Use in Urinary Tract Infections. Drugs. 1982 Jun;23(6):405-30.
[3]. Xiaojian Wang, et al. A Trimethoprim Conjugate of Thiomaltose Has Enhanced Antibacterial Efficacy In Vivo. Bioconjug Chem. 2018 May 16;29(5):1729-1735.