In findings that underscore concern and confusion about the implications of antibiotic resistance and dentistry, a 20-year study shows a marked increase in resistance of Porphyromonas gingivalis, the main pathogen of gingivitis, as well as other periodontitis-associated bacteria.
Using biofilm samples from three sets of patients with severe periodontitis from three time frames—1999–2000, 2009–2010, and 2019–2020—researchers from the Temple University School of Dentistry and the University Medical Center Groningen in the Netherlands determined that in the earliest set of patients, resistance to clindamycin affected .6% of patients, but by the last set, that percentage rose to 9.3%. P. gingivalis resistance to amoxicillin increased from 0.1% of patients in 1999–2000 to 2.8% in 2019–2020, a 28-fold increase.
Regional exposure plays an important role in antibiotic resistance, according to the study, which notes that the prevalence of antibiotic-resistant P. gingivalis and other periodontal pathogens varies considerably between countries and geographic regions, “[underscoring] the need for region-specific surveillance monitoring of antibiotic resistance trends among periodontopathic bacterial species.”
The study authors say the findings are the first to show substantial increases over 20 years in clindamycin-resistant and amoxicillin-resistant P. gingivalis in US periodontitis patients, calling the current rate of US clindamycin resistance “alarming.”
“Clindamycin was shown over 3 decades ago to be useful in resolving P. gingivalis-associated refractory cases of periodontitis and arresting progressive periodontal attachment loss… Clindamycin is additionally recommended by the American Academy of Periodontology as an empirical antibiotic choice in the treatment of periodontal abscesses, where P. gingivalis is often part of the associated microbial etiology,” the study states. “However, due to the increased prevalence of clindamycin-resistant P. gingivalis, as documented in the present study, these recommendations likely need to be reconsidered and appropriately modified.”
Dentists are the top prescribers of clindamycin, the most common antibiotic leading to Clostridioides difficile (C. diff). Per the American Heart Association, clindamycin is no longer recommended for antibiotic premedication for dental procedures.
The study also determined that the P. gingivalis resistance rates of several other antibiotics—metronidazole, metronidazole plus amoxicillin, and doxycycline—showed no significant changes over the 20-year period studied, supporting their continued use.
Access the study: Emergence of Antibiotic-Resistant Porphyromonas gingivalis in United States Periodontitis Patients
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