Toothbrush
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Description of Niche
Introduction
The toothbrush is a tool used by everybody on a daily basis, so it is one of the most important pieces of equipment known for good dental hygiene. But sadly, toothbrushes are most commonly found in a bathroom near the sink, which is a good place to harvest hundreds of microorganisms no matter how well one cleans them because it is constantly exposed to open air and not well stored. According to researchers at the University of Arizona, the bathroom sink is the third most germ infested place in the house. The study also shows the bathroom floor, bathroom counter, and toilet seat stealing spots in the top 10. Many objects in the bathroom, like a toothbrush, are thus vulnerable to bacteria as well. ****Although not a very favorable location for bacteria such as Candidas and Streptococcus, they are passed along from the mouth onto a toothbrush.****--> this sentence doesn't make sense-Natalie
Toothbrush as a niche
What are the conditions in your niche? Temperature, pressure, pH, moisture, etc.
A new toothbrush is usually not a favorable habitat for bacteria and fungi, but in some cases, toothbrushes are already slightly infected because there is not a regulation that states toothbrushes must be sold in a sterile package1 [Glass RT, Lare MM]. Usually, the presence of microbes on the toothbrush is due to brushing. Tooth brushing introduces the toothbrush into the mouth, which is a niche hospitable to many kinds of microbes. Therefore, the bacteria will transfer from the inside of the mouth to the toothbrush2. In this way, the toothbrush is considered a niche for many microbes.
A toothbrush contains little nutrients; usually food particles that are trapped after brushing serve as the nutrients for the microorganisms. Bacteria in mouths can transfer to toothbrushes, so active brushing will cause bacteria to always be present on the toothbrush. While on the toothbrush, bacteria do a small amount of multiplying and the population decreases with time. In fact, right after the toothbrush is put away after use, the transferred bacteria can survive up to 6 hours of air drying on the toothbrush niche [K. Kozai]. Another study on Streptococcus mutans by a group of scientists in National University of Tucumán, Tucumán, Argentina verified that these organisms can survive on the toothbrush bristles up to 8-10 hours2 in open air. Moreover, a study showed that the majority of reduction of microorganisms happens within 0 to 4 hours after brushing. Within 4 to 24 hours, the decrease in bacteria population was less apparent. When toothpaste was used, brushes showed substantially lower numbers of "colony-forming units" compared to those without the use of toothpaste [M. Efstratiou]. People brush at least twice a day, so the bacteria population never completely dies out, but is rather reharvest each time the toothbrush comes in contact with the mouth again.
Influence by Adjacent Communities (if any)
Is your niche close to another niche or influenced by another community of organisms?
Microbes that inhabit a toothbrush must come from somewhere, and a good amount of bacteria on the toothbrush originate from just the mouth, a niche that inhabits a plethora of microbes. The contact of the toothbrush with an oral cavity will thus cause microbes to transfer to the toothbrush.
In addition, a toothbrush's niche can be affected by another nearby toothbrush through cross contamination in a communal environment is likely, since a typical household uses a holder to store multiple toothbrushes. Bacteria living on one toothbrush can thus be transferred to another nearby toothbrush during accidental contact [Peter R. Neal]. Occurrences like these will spread disease and cause another person to be sick when using the newly infected toothbrush. The same idea of bacteria transfer applies when sharing a toothbrush, which is bad hygiene practice.
Therefore, it makes sense that individuals should store their toothbrushes in separate holders or locations. The exception is storing a toothbrush in a closed container or cabinet. According to the American Dental Association, dark and moist environments are more favorable towards the growth of microorganisms than open air. A study on Streptococcus mutans by a group of scientists in National University of Tucumán, Tucumán, Argentina verified that organisms like Candida Albicans can survive on the toothbrush bristles up to 8-10 hours depending on condition of the environment. In addition, though many studies and dentists take a different stance on when to change a toothbrush, one should do it every 2-3 months at the very least.
An experiment performed by Dr. Charles Peter Gerba tested whether bacteria ejected from the toilet bowl were landing on surfaces in the bathroom. Results showed that during the first two hours, bacteria were mostly found in a limited area near the toilet. After longer intervals, bacterial colonies were found to be more randomly distributed. The detection of coliform bacteria onto surfaces
after flushing was also observed [GERBA]
Conditions under which the environment changes
The environments of toothbrushes are typically ambient for most cases. The chemicals in the toothpaste can alter the pH of the toothbrush by making it more basic because most toothpaste has basic chemical compositions1. The active ingredient is the reactive fluoride ions which are acidic but their concentrations are negligible compared to other chemical agents in the toothpaste1. The pH of a toothbrush is strictly determined by the chemical residues left behind after brushing which is the toothpaste itself with other minor factors. If the toothbrush is thoroughly washed with tap water, then the pH generally varies from 6-8 which is the pH of tap water. Once the toothbrush has dried, the microbe is no long affected by the environmental pH.
Who lives there?
There is a surprising number of microbes that live on a toothbrush which evaluated by Fernandes, V. H. and Cesar, D. L. A commonly identified pathogenic fungus is Candida and some pathogenic bacteria include Streptococcus, Staphylococcus and Lactobacillus which are all gram positive. These microorganisms could potentially cause diseases like gingivitis, pharyngitis, candidiasis, laryngitis, and dental decay if oral hygiene is not well maintained.
Which microbes are present?
You may refer to organisms by genus or by genus and species, depending upon how detailed the your information might be. If there is already a microbewiki page describing that organism, make a link to it.
Are there any other non-microbes present?
Plants? Animals? Fungi? etc. Candida albicans is a type of yeast that can be found on a toothbrush. It prefers to live in environments with low pH levels and a lot of moisture. Candida albicans are opportunistic human fungal pathogens that can cause disease in individuals who are immunocompromised such as HIV/AIDS patients, individuals undergoing chemotherapy or individuals who have had a recent organ transplant (I, II).
Candida albicans are one type of many organisms that prefer the human mouth as their primary habitat but have abilities that allow them to survive on the barren surface of a toothbrush if they find themselves stranded there. C. albicans can do this by morphing from a free floating or planktonic form to one that is sessile and grows as a community in a biofilm. Biofilms may allow for overpopulation and nutrient load regulation. The formation of a biofilm requires C. albicans to grow hyphae which are multinucleated cell filments that absorb nutrients. They decide to build communities and grow hyphae based on different environmental and cell signals such as an increase in temperature, increase in pH levels, nutrient starvation and increased cell density (Martins)
Do the microbes that are present interact with each other?
Describe any negative (competition) or positive (symbiosis) behavior
Not only does Candida form biofilms among each other, but they also incorporate a variety of microbes into the biofilm that can benefit one other. A study was done on the effect of Streptococcus mutans and Candida glabrata on Candida albicans biofilms to better understand the interactions between multiple species of microbes and their environment. This is important because yeasts can easily re-colonize the oral cavity of an individual who has just undergone antimycotic treatment for oral candidosis, a fungal infection of the mucus membranes in the mouth (IV).
In their study, they observed that when Streptococcus mutans were present, the growth of both Candida albicans and Candida glabrata increased. These results suggest that the microorganisms may co-aggregate in order to enhance the adhesion process in biofilm formation. Not only did S. mutans increase the growth of both Candida species, but they also found a stimulatory effect between C. glabrata and C. albicans when they were co-cultured. By better understanding how these microbes survive in remote sites, such as a toothbrush, oral cavity re-colonization can be avoided by developing better sterilization techniques (IV).
Do the microbes change their environment?
Do they alter pH, attach to surfaces, secrete anything, etc. etc.
One way that C. albicans obtain what nutrients are on a toothbrush is through a regulatory cascade that controls the secretion of aspartic protease (Saps). C. albicans secrete Saps into their environment to degrade proteins and use them as a nitrogen source when there are no other nitrogen sources available such as ammonium or amino acids (III). This may also benefit other microbes in the biofilm by producing nitrogen in the environment that is available to be taken up.
Do the microbes carry out any metabolism that affects their environment?
Do they ferment sugars to produce acid, break down large molecules, fix nitrogen, etc. etc.
C. albicans and C. glabrata grow in higher numbers in the presence of glucose when compared with sucrose but can survive and grow when either one is available on a toothbrush (IV).
Current Research
Enter summaries of the most recent research. You may find it more appropriate to include this as a subsection under several of your other sections rather than separately here at the end. You should include at least FOUR topics of research and summarize each in terms of the question being asked, the results so far, and the topics for future study. (more will be expected from larger groups than from smaller groups)
References
Edited by [James Lin, Natalie Nguyen, Nicholas Phung, Sarah Fernandes], students of Rachel Larsen
