Chlorhexidine

Chlorhexidine is a bis(biguanide) antimicrobial disinfectant and antiseptic agent.¹ It inhibits growth of clinical methicillin-resistant S. aureus (MRSA) isolates (MIC₉₀ = 4 μg/ml).² It is also active against canine isolates of MRSA, methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. pseudintermedius (MRSP), and methicillin-susceptible S. pseudintermedius (MSSP; MIC₉₀s = 4, 2, 2, and 1 mg/L, respectively).³ Chlorhexidine inhibits growth of E. faecium strains (MICs = 1.2-19.6 μg/ml) and C. albicans (MIC = 5.15 μg/ml).^4,5 It generates cations that bind to and destabilize the bacterial cell wall to induce death.⁶ Chlorhexidine also completely inhibits matrix metalloproteinase-2 (MMP-2) and MMP-9 when used at concentrations of 0.0001 and 0.002%, respectively, in a gelatin degradation assay.⁷ Formulations containing chlorhexidine have been used in antiseptic wound dressings, mouthwash, and toothpaste.

1.Karpiński, T.M., and Szkaradkiewicz, A.K.Chlorhexidine--Pharmaco-biological activity and applicationEur. Rev. Med. Pharmacol. Sci.19(7)1321-1326(2015) 2.McDanel, J.S., Murphy, C.R., Diekema, D.J., et al.Chlorhexidine and mupirocin susceptibilities of methicillin-resistant Staphylococcus aureus from colonized nursing home residentsAntimicrob. Agents Chemother.57(1)552-558(2013) 3.Clark, S.M., Loeffler, A., and Bond, R.Susceptibility in vitro of canine methicillin-resistant and -susceptible staphylococcal isolates to fusidic acid, chlorhexidine and miconazole: Opportunities for topical therapy of canine superficial pyodermaJ. Antimicrob. Chemother.70(7)2048-2052(2015) 4.Bhardwaj, P., Hans, A., Ruikar, K., et al.Reduced chlorhexidine and daptomycin susceptibility in vancomycin-resistant enterococcus faecium after serial chlorhexidine exposureAntimicrob. Agents Chemother.62(1)e01235-01217(2017) 5.Scheibler, E., da Silva, R.M., Leite, C.E., et al.Stability and efficacy of combined nystatin and chlorhexidine against suspensions and biofilms of Candida albicansArch. Oral Biol.8970-76(2018) 6.Barrett-Bee, K., Newboult, L., and Edwards, S.The membrane destabilising action of the antibacterial agent chlorhexidineFEMS Microbiol. Lett.119(1-2)249-253(1994) 7.Gendron, R., Grenier, D., Sorsa, T., et al.Inhibition of the activities of matrix metalloproteinases 2, 8, and 9 by chlorhexidineClin. Diag. Lab. Immun.6(3)437-439(1999)