Abstract
Testing the sensitivity of periodontal pathogens requires the selection of an easier and more reliable method to be used with such anaerobic bacteria that need a long period of time for growth. Natural materials are a new era of antibacterial agents to control periodontal infections. The aims of the current study were to test the antibacterial activity of two natural agents, namely olibanum and alum, against three types of red complex periodontal pathogens and compare the application of agar diffusion and microdilution methods for testing the susceptibility. Gingival crevicular fluid from pockets with chronic infections was sampled as a source for the three types of bacteria, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola (the red complex pathogens). The samples (n= 30) were cultured on three types of media, namely Schaedler Anaerobe Agar, Tannerella forsythia (TF) agar, and Trypton Yeast extract Gelatin Volatile fatty acids and Serum (TYGVS) agar for the three types of red complex pathogens. After anaerobic growth, the isolates of red complex pathogens were identified by cultural and cellular morphological characteristics and confirmed by molecular diagnosis. The antibacterial activity of the two natural materials was tested by agar (disk and well) diffusion and microdilution method (spectrophotometer- and resazurin- based). Ciprofloxacin (CIP) and chlorhexidine (CHX) were used as controls. Minimal Inhibitory Concentrations (MICs) of the four reagents (olibanum, alum, CIP, and CHX) were determined on the three types of bacteria. MIC values by each susceptibility method were compared and analyzed statistically at p- value ≤ 0.05. The results showed that resazurin- based microdilution method was the easiest and simplest approach which gave reliable reads. MIC values of the four regents differed from a method to another and from one bacterium to another. Statistically, there were no significant values among these differences, except for olibanum which was statistically more significant than the other reagents.
Highlights
Screening the activity of crude extracts or purified compounds form natural substances requires the employment of a simple, rapid, reliable, sensitive and cost- effective in vitro assay
Anaerobic susceptibility testing (AST) methods standardized by the Clinical and Laboratory Standards Institute (CLSI) include agar dilution, broth microdilution, and E- test [2]
Standard diameters of the inhibition zone are available for comparing the results of only the tests for standard antibiotics, but there are no standard explanations for comparing the results of the tests of natural materials [4]
Summary
Screening the activity of crude extracts or purified compounds form natural substances requires the employment of a simple, rapid, reliable, sensitive and cost- effective in vitro assay. 96-Well plate microdilution and Resazurin- based assay: As formerly designated [4], two sets of plates, one for spectrophotometer assay and the other for resazurin assay, were prepared as follows: A stock solution of each reagent was prepared in a broth medium of each bacterial type at 50% (w/v) for olibanum, 60% (w/v) for alum, and 50% (v/v) for CIP and CHX.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
