title: In vitro evaluation of MTAD and nisin in combination against common pathogens associated with root canal infection.
abstract: BACKGROUND
  Many pathogenic microorganisms were found in an infected root canal. The object of this study was to evaluate the effect of MTAD in combination with nisin on the pathogens associated with root canal infection.
  
  
  METHODS
  The survival rates of 9 pathogenic bacteria were determined after 1-, 5-, and 10-minute treatment with MTAD, MTAN (substitution of doxycycline with nisin), and MTADN (nisin in combination with doxycycline). The survival rates of Enterococcus faecalis in the starvation phase and pretreatment alkalization as well as in the normal physiological state under MTAD, MTAN, and MTADN challenge for 1, 5, and 10 minutes were evaluated and compared. Furthermore, scanning electron microscopy was used to observe the morphologic modification of Actinomyces naeslundii, Lactobacillus paracasei, and Porphyromonas gingivalis after MTAD and MTADN treatment.
  
  
  RESULTS
  L. fermenti, L. paracasei, A. viscosus, A. naeslundii, Streptococcus gordonii, and Peptostreptococcus were more sensitive to MTADN and MTAN than to MTAD. MTAD, MTAN, and MTADN showed a rapid antibacterial effect on P. gingivalis, Prevotella intermedia, and Fusobacterium nucleatum. Enterococcus faecalis in the stress state was as sensitive to MTAD, MTAN, and MTADN as the control E. faecalis. Furthermore, in the observation of scanning electron microscopy, the membranes in A. naeslundii and L. paracasei presented significant rupture, and P. gingivalis did not exhibit significant damage after MTADN treatment.
  
  
  CONCLUSIONS
  MTAD in combination with nisin improved antibacterial efficacy against pathogens, especially for some gram-positive bacteria associated with persistent intracanal infection. Therefore, the combination had the potential to be used as an effective intracanal irrigation.
authors.affiliation: Department of Operative Dentistry and Endodontics, School of Stomatology, Fourth Military Medical University, Shaanxi, China.
authors.forename: Zhongchun
authors.initials: Z
authors.lastname: Tong
authors.forename: Lin
authors.initials: L
authors.lastname: Zhou
authors.forename: Rong
authors.initials: R
authors.lastname: Kuang
authors.forename: Haipeng
authors.initials: H
authors.lastname: Lv
authors.forename: Tiejun
authors.initials: T
authors.lastname: Qu
authors.forename: Longxing
authors.initials: L
authors.lastname: Ni
mesh_terms: D000190:Actinomyces / Q000187:drug effects; D016924:Actinomyces viscosus / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018407:Bacterial Physiological Phenomena / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D019343:Citric Acid / Q000494:pharmacology*; D003788:Dental Pulp Diseases / Q000382:microbiology*; D004318:Doxycycline / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D013293:Enterococcus faecalis / Q000187:drug effects; D016967:Fusobacterium nucleatum / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D007778:Lactobacillus / Q000187:drug effects; D052197:Limosilactobacillus fermentum / Q000187:drug effects; D050296:Microbial Viability / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D009561:Nisin / Q000494:pharmacology*; D010462:Peptostreptococcus / Q000187:drug effects; D011136:Polysorbates / Q000494:pharmacology*; D016966:Porphyromonas gingivalis / Q000187:drug effects; D018713:Prevotella intermedia / Q000187:drug effects; D012388:Root Canal Irrigants / Q000494:pharmacology*; D054773:Streptococcus gordonii / Q000187:drug effects; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; C475043:MTAD (intracanal irrigant); D011136:Polysorbates; D012388:Root Canal Irrigants; D009561:Nisin; D019343:Citric Acid; D004318:Doxycycline