Dental equipment is never clean of bacteria

Dental equipment is never clean of bacteria, reports a new study published in Water Research. Dental equipment is particularly prone to contamination with bacteria, yeasts and other microbes because it comes into contact with people’s mouths and even though they are regularly disinfected and cleaned after each use, the water they use is questionable. Dentists also use dental unit water lines to keep their electrical equipment cool. A team of researchers from Université de Poitiers in France analyzed three disinfectants used by some European dentists to control biofilms in dental water lines: Calbenium®, Oxygenal 6® and Sterispray®. The team tested how well the disinfectants removed biofilms from dental water lines and found that none of them were completely effective on a polymicrobial biofilm. Calbenium® was most effective at clearing biofilms and stopping new ones from forming, however, it did not kill the free living amoebae – Vermamoeba vermiformis which are also known as “Trojan horses” because they carry some bacteria that can infect humans, like Legionella pneumophila, which causes Legionnaire’s disease. “Infections may occur if this potentially microbiologically contaminated water is inhaled or splashed”, says Dr. Damien Costa, lead author of the study. Preventing the formation of biofilms as long as possible is key to keeping the lines clean, as once they have formed, they can’t be killed using disinfectant. Read the press release byEurekAlert, Science Codex and Medical Xpress.

This paper published in the European Journal of Microbiology and Immunology was highlighted in a press release by the University of New Haven. The study is the first to show the presence of Borrelia biofilm in human infected skin tissues, confirming that these structures indeed can exist in the human body. Lyme borreliosis, caused by the spirochete Borrelia burgdorferi sensu lato, has grown into a major public health problem. Often, it seems to recur as soon as the antibiotics are discontinued, and doctors are reluctant to offer more and more rounds of antibiotics. Researchers led by Professor Eva Sapi, professor and head of biology and environmental science at the University of New Haven, reexamined the archived skin biopsy tissues from borrelial lymphocytomas (BL) for the presence of B. burgdorferi sensu lato using Borrelia-specific immunohistochemical staining (IHC), fluorescent in situ hybridization, combined fluorescent in situhybridization (FISH)—IHC, polymerase chain reaction (PCR), and fluorescent and atomic force microscopy methods. Morphological and histological analyses revealed the presence of Borrelia biofilm in human infected skin tissues. The findings demonstrate that the microorganisms that cause Lyme Disease are resistant to treatment because they form a biofilm in the body that allows it to “hide out” from antibiotics. Researchers hope that the discovery will leave clues for future therapies down the road.

A new paper published in Cell Reports was picked up by several media outlets including EurekAlert, Newsweekand Genome Web. The study sheds light on how lifestyle and diet changes have impacted the evolution of human gut microbiome. An international team led by researchers from the University of Minnesota used 16S ribosomal RNA gene sequencing to identify microbial community members in fecal samples from dozens of individuals from Central African Republic’s Dzanga region, including members of a rainforest hunter-gatherer group — the BaAka — and individuals from a Bantu-speaking population practicing subsistence agriculture with some westernized diet and lifestyle practices. The findings revealed a diet-related gut microbiome continuum: the Bantu gut microbiomes edged closer to those described in individuals from the US. At the other end of the spectrum, the BaAka individuals had gut microbiomes that seemed to coincide with more traditional diets. Although the microbiome of both groups was compositionally similar, the abundance of traditional bacterial groups was diminished in the Bantu. Further analyzing the functions of the different bacterial communities, researchers found a potential gradient between the BaAka and western microbes in pathways involved in processing carbohydrates and foreign substances. “We suspect that the enrichment in carbohydrate- and xenobiotic-processing pathways that we see in Bantus and US Americans is related to access to more digestible sugars and therapeutic drugs, while the hunter-gatherers consume more fibrous plants and do not have access to drugs or antibiotics,” said first author Andres Gomez, a microbial ecologist and staff scientist at the J. Craig Venter Institute in California. “The study supports the idea that diet is the most important driver of microbiome composition in humans. We are what we eat, and our microbiome is a very important reflection of lifestyle.”

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