The Antibacterial Action of the Various Components of the Lactoperoxidase System on a Cariogenic Strain of Streptococcus mutans (original) (raw)
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The lactoperoxidase (LPO) system shows promise in the prevention of dental caries, a common chronic disease. This system has antimicrobial properties and is part of the non-specific antimicrobial immune system. Understanding the efficacy of the LPO system in the fight against biofilms could provide information on alternative strategies for the prevention and treatment of caries. In this study, the enzymatic system was modified using four different (pseudo)halide substrates (thiocyanate, thiocyanate-iodide mixture, selenocyanate, and iodide). The study evaluated the effects of such modifications on the ability of Streptococcus mutans to form a biofilm, the synthesis of insoluble polysaccharides, the synthesis of lactate, the consumption of glucose and sucrose, the concentrations of intracellular NAD+ and NADH and the efficiency of transmembrane glucose transport by phosphoenolpuryvate PEP-carbohydrate phosphotransferase (PTS). The results showed that the LPO-iodide system had the str...
Isolation and Antimicrobial Activity of Lactic Acid Bacteria against Streptococcus Mutans
2020
The aim of this study was to isolate lactic acid bacteria (LAB) from fermented food, to determine its antibacterial activity, and to identify the LAB in order to select candidate probiotic strains for preventing caries. The probiotic strains were isolated from eight fermented food which are tapai ubi, tapai pulut, rebung, tauchu, kimchi, cincalok, tempeh and tempoyak, taucu. Ten-fold serial dilutions of the fermented food samples were made in sterile peptone water before plating on de Man Rogosa and Sharpe (MRS) agar. The pure cultures were then randomly picked and biochemically identified. Then, the antibacterial activity of LAB against Streptococcus mutans was assessed by using the disk diffusion method. A total of 120 LAB were isolated from eight different fermented foods. The morphologies of the isolates were circular, convex, dull opaque white or translucent white. Gram staining identification showed that the isolates were Gram-positive rods. Of the 120 LAB isolates, five strai...
Infection and …, 1994
In secreted fluids, the enzyme lactoperoxidase (LP) catalyzes the oxidation of thiocyanate ion (SCN-) by hydrogen peroxide (H202), producing the weak oxidizing agent hypothiocyanite (OSCN-), which has bacteriostatic activity. However, H202 has antibacterial activity in the absence of LP and thiocyanate (SCN-). Therefore, LP may increase antibacterial activity by using H202 to produce a more effective inhibitor of bacterial metabolism and growth, or LP may protect bacteria against the toxicity of H202 by converting H202 to a less-potent oxidizing agent. To clarify the role of LP, the antibacterial activities of H202 and the LP-H202-SCNsystem were compared by measuring loss of viability and inhibition of bacterial metabolism and growth. The relative toxicity of H202 and the LP system to oral streptococci was found to depend on the length of time that the bacteria were exposed to the agents. During incubations of up to 4 h, the LP system was from 10 to 500 times more effective than H202 as an inhibitor of glucose metabolism, lactic acid production, and growth. However, if no more H202 was added, the concentration of the inhibitor OSCNfell because of slow decomposition of OSCN-, and when OSCNfell below 0.01 mM, the bacteria resumed metabolism and growth. In contrast, the activity of H202 increased with time. H202 persisted in the medium for long periods of time because H202 reacted slowly with the bacteria and streptococci lack the enzyme catalase, which converts H202 to oxygen and water. After 24 h of exposure, H202 was as effective as the LP system as an inhibitor of metabolism. H202 also caused a time-dependent loss of viability, whereas the LP system had little bactericidal activity. The concentration of H202 required to kill half the bacteria within 15 s was 1.8 M (6%) but fell to 0.3 M (1%) at 2 min, to 10 mM (0.03%) at 1 h, and to 0.2 mM (0.0007%) with a 24-h exposure. The results indicate that if high levels of H202 can be sustained for long periods of time, H202 is an effective bactericidal agent, and the presence of LP and SCNprotects streptococci against killing by H202. Nevertheless, the combination of LP, H202, and SCNis much more effective than H202 alone as an inhibitor of bacterial metabolism and growth.
Beneficial effects of Lactobacillus sp. against Streptococcus mutans
2018
Probiotics are known for their beneficial effects to health and their action is often linked to the GI health. Oral health is owed to the ecological balance in the oral cavity, still considering the pathogen Streptococcus mutans primarily responsible for initiating dental caries and tooth decay, as well as periodontal disease. Studies have shown that different Lactobacillus species can exert beneficial effects in oral health as well as GI health. The main goal of this research is to examine the reported positive effect of Lactobacillus against oral diseases, caused by S. mutans. Several studies have shown that co-culture of S. mutans with different Lactobacillus strains significantly reduced the numbers of S. mutans and total bacteria in the mixed biofilm cultures compared with the control group. Different Lactobacillus strains have varying inhibition activity against S. mutans. In one study, it has been shown that Lactobacillus acidophilus has a reducing power to gene expression, a...
BMC Microbiology, 2009
Background: The positive antimicrobial effects of increasing concentrations of thiocyanate (SCN-) and H 2 O 2 on the human peroxidase defence system are well known. However, little is known about the quantitative efficacy of the human peroxidase thiocyanate H 2 O 2 system regarding Streptococcus mutans and sanguinis, as well as Candida albicans. The aim of this study was to evaluate the effect of the enzyme lactoperoxidase on the bactericidal and fungicidal effectiveness of a thiocyanate-H 2 O 2 combination above the physiological saliva level. To evaluate the optimal effectiveness curve, the exposure times were restricted to 1, 3, 5, and 15 min. Results: The bactericidal and fungicidal effects of lactoperoxidase on Streptococcus mutans and sanguinis and Candida albicans were evaluated by using two test mixtures of a 2.0% (w/v; 0.34 M) thiocyanate and 0.4% (w/v; 0.12 M) hydrogen peroxide solution, one without and one with lactoperoxidase. Following the quantitative suspension tests (EN 1040 and EN 1275), the growth of surviving bacteria and fungi in a nutrient broth was measured. The reduction factor in the suspension test without lactoperoxidase enzyme was < 1 for all three tested organisms. Thus, the mixtures of 2.0% (w/v; 0.34 M) thiocyanate and 0.4% (w/v; 0.12 M) hydrogen peroxide had no in vitro antimicrobial effect on Streptococcus mutans and sanguinis or Candida albicans. However, the suspension test with lactoperoxidase showed a high bactericidal and fungicidal effectiveness in vitro. Conclusion: The tested thiocyanate and H 2 O 2 mixtures showed no relevant antimicrobial effect. However, by adding lactoperoxidase enzyme, the mixtures became not only an effective bactericidal (Streptococcus mutans and sanguinis) but also a fungicidal (Candida albicans) agent.
Mode of action of lactoperoxidase as related to its antimicrobial activity: a review
Enzyme research, 2014
Lactoperoxidase is a member of the family of the mammalian heme peroxidases which have a broad spectrum of activity. Their best known effect is their antimicrobial activity that arouses much interest in in vivo and in vitro applications. In this context, the proper use of lactoperoxidase needs a good understanding of its mode of action, of the factors that favor or limit its activity, and of the features and properties of the active molecules. The first part of this review describes briefly the classification of mammalian peroxidases and their role in the human immune system and in host cell damage. The second part summarizes present knowledge on the mode of action of lactoperoxidase, with special focus on the characteristics to be taken into account for in vitro or in vivo antimicrobial use. The last part looks upon the characteristics of the active molecule produced by lactoperoxidase in the presence of thiocyanate and/or iodide with implication(s) on its antimicrobial activity.
Antibacterial Effect of Salivary Peroxidases on a Cariogenic Strain of Streptococcus mutans
Journal of Dental Research, 1977
The antibacterial effect of purified human salivary lactoperoxidase on a cariogenic strain of Streptococcus mutans was demonstrated while another oral peroxidase, probably of leukocytic origin, did not affect the growth. Lactoperoxidase was rapidly adsorbed by bacterial cells indicating the necessity of the contact between the enzyme and the cells before inhibition.
Evaluation of Probiotic Effects of Lactobacilli on Mutans Streptococci: An In Vitro Study
The Journal of Contemporary Dental Practice, 2022
Aim: The aim of the present study is to evaluate the probiotic effect of Lactobacillus acidophilus and Lactobacillus rhamnosus on clinical isolates of Mutans Streptococci (MS) and antibiotic susceptibility of these strains to commonly used antibiotics in dentistry. Materials and methods: Plaque samples from permanent first molars were collected and transferred aseptically onto Mitis-Salivarius agar and incubated at 37°C for 24 hours in the presence of 5-10% CO 2. Mutans streptococci colonies were identified biochemically using Hi-Strep identification kit. The inhibitory activity of the clinical strains of MS on Lactobacilli was investigated using agar-overlay interference technique. Positive inhibition was appreciated as a clear zone around the Lactobacilli. Disk diffusion assay was done as described by CLSI M100-S25 for antibiotic susceptibility. The zone of growth inhibition caused by Lactobacilli and antibiotics on MS clinical strains was measured directly using a vernier caliper. Statistical analysis was done using independent t-test. Results: Mutans streptococci exhibited positive inhibition with both the probiotic strains and L. acidophilus showed more zones of inhibition than L. rhamnosus. Antibiotic susceptibility of clinical strains of MS showed sensitivity to penicillin and vancomycin, however, tetracycline and erythromycin showed very few resistant strains. The highest zone of inhibition was shown by cephalothin followed by penicillin, tetracycline, ciprofloxacin, erythromycin, and vancomycin. Conclusion: L. rhamnosus and L. acidophilus have strong inhibitory effects on clinical strains of MS. Lactobacillus acidophilus showed a higher zone of inhibition. All the clinical strains of MS were sensitive to penicillin and vancomycin. The highest zone of inhibition was shown by cephalothin. Clinical significance: Dental caries remains silent epidemic and increasing antibiotic resistance is another major challenge that threatens the world. Newer methods such as whole-bacteria replacement therapy using probiotics for decreasing harmful oral pathogens and reducing the intake of antibiotics must be explored. More researches to promote use of probiotics should be initiated due to its possible preventive and health maintenance benefits providing an end to new cavities and antibiotic resistance.
Archives of Oral Biology, 1985
Teeth were inoculated with either the organisms separately or with a freshly-prepared mixture of both. The apparatus was swept with 5 per cent (v/v) CO, in either air or N, , and incubated for 90 h. A nutrient supplement containing 1 per cent (w/v) glucose was supplied for 1 h in every 6 h. Both organisms achieved similar numbers when grown aerobically in pure culture, yet in mixed culture there was pronounced inhibition of BHT (p < 0.001). When the synthetic saliva was supplemented with catalase the strain BHT count in mixed culture was much higher (p < 0.001). It was concluded, therefore, that the strain LPA-I produced inhibitory levels of hydrogen peroxide (H,O,) on the tooth surface under aerobic conditions. This was supported by finding that a lower viable count of LPA-I in pure culture was attained when lactoperoxidase (LPO) was included in the saliva (p i 0.005), as all components of the LPGSCN-H,O, system were presumably present. With the Nr-CO, mixture, conditions were not strictly anaerobic and both catalase and LPO increased all viable counts. Under these conditions, therefore, when H,O, was limiting, LPO protected bacteria against its bactericidal effect.