Oral microbes exhibit bacterial resistance to conventional antiseptics

Streptococcus mutans, Lactobacillus acidophilus and other oral microbes may exhibit bacterial resistance to antiseptics, including chlorhexidine, according to a review. Moreover, resistance may increase over time.

Cavity microbes mouths exhibit bacterial resistance to conventional antiseptics.

This is believed to be the first review to examine the prevalence and proportions of antiseptic-resistant species in dental patients assessed in randomized clinical trials.

“This review may help clinicians and public health leaders make important decisions and better understand the importance of judicious use of antiseptics,” write the authors, led by Dr. Carlos Ardila, Ph.D., a periodontist and professor at the University of Antioquia in Colombia.

Antimicrobial resistance is a public health threat that resulted in more than 1.2 million deaths worldwide in 2019, according to the US Centers for Disease Control and Prevention (CDC). According to the CDC, approximately 3 million antimicrobial-resistant infections are diagnosed each year in the United States.

Recently, much attention has been paid to antibiotic resistance, and less attention has been paid to the directly related problem of resistance to antiseptics, including triclosan and chlorhexidine, which are widely used in dentistry as mouthwashes.

To examine the prevalence and proportions of bacterial resistance to antiseptics commonly used in dentistry, the authors reviewed five randomized clinical trials that were published between 1994 and 2021 and included 442 patients. The review included only studies that included healthy participants, as well as phenotypic analysis and antimicrobial susceptibility data. According to the authors, the trials lasted from 10 days to 12 months.

In patients at risk of developing caries, Streptococcus mutans and Lactobacillus acidophilus showed resistance to chlorhexidine, and this resistance only increased during the observation period. In patients with gingivitis, Veillonella species showed resistance to triclosan at baseline and during testing. In addition, after six months of follow-up, a slight increase in the proportion of resistant strains was observed.

Although four of the trials reviewed were classified as high quality, one was still at risk of bias. However, it was important to highlight that the trials showed great heterogeneity in their design, as well as great variability in study patient characteristics and microbiological identification.

“While adjunctive antimicrobials are useful tools during dental practice, there are underlying concerns about oral changes resulting from their use,” Ardila and colleagues write.