This Week In Biofilms And Microbiomes: Monday May 23, 2016

A round-up of what we read last week in the media's coverage of biofilms and microbiomes research.

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Does the antibiotic agent in toothpaste and soap impact our gut microbiome? There is a divided view coming from the scientific community. The studies published in the journals, mSphere and Plos One voice different opinions. Triclosan, a common anti-microbial ingredient, which is also found in various household items such as toothpaste, shampoo, soap, deodorant and even some toys, bedding and bin bags, can be easily absorbed through the skin and gut. In this study, scientists from Oregon State University exposed forty-five adult zebrafish to triclosan-laden food for four or seven days or a control diet, and analyzed their microbial communities using 16S rRNA amplicon sequencing. They noticed that Triclosan exposure was associated with rapid shifts in microbiome structure and diversity. The team found evidence that several operational taxonomic units (OTUs) associated with the family Enterobacteriaceae appear to be susceptible to triclosan exposure, while OTUs associated with the genus Pseudomonas appeared to be more resilient and resistant to exposure. It was also observed that triclosan exposure is associated with topological alterations to microbial interaction networks and results in an overall increase in the number of negative interactions per microbe in these networks, suggesting that triclosan exposure results in altered composition and ecological dynamics of microbial communities in the gut. But this doesn't mean we should panic, according to Dr. Julie Parsonnet, a professor at Stanford School of Medicine. After leading a "small randomised" study into the effects of Triclosan, she disputed the notion that it is potentially harmful. Her team recruited 13 healthy volunteers to take part in a novel eight-month-long experiment. Randomly divided into two groups, half regularly used soaps and toothpastes containing triclosan and triclocarban (TCS), while the other half was told to avoid any such products (nTCS). After four months, the groups switched their roles. During each leg of the experiment, the researchers mapped out the microbial environment, or microbiome, of the volunteers’ mouths and guts, looking for any subtle changes. They also tested their blood and urine. Although there was a significant difference in the amount of triclosan in the urine between the TCS and nTCS phases, no differences were found in microbiome composition, metabolic or endocrine markers, or weight. Both papers have been in limelight this week and were picked up by several media outlets, including, Science Daily, Medical Daily, Pulse Headlines and many more.

A compound extracted from Antarctic sea sponge can kill the deadly bacterial infection, methicillin-resistant Staphylococcus aureus (MRSA), reports a new study published in the American Chemical Society's journal Organic Letters. The compound comes from a sea sponge known as Dendrilla membranosa and has been named "darwinolide" by the team of researchers from the University of South Florida. In tests, the extract was able to kill more than 98 percent of methicillin-resistant Staphylococcus aureus (MRSA) cells, which is a type of staph bacteria that has grown resistant to many antibiotics. MRSA is unique in that it can cause infections in almost every niche of the human host, from skin infections, to pneumonia, to endocarditis, a serious infection of tissues lining the heart. MRSA was once a serious problem only in health care settings, such as hospitals and nursing homes. But the infection is now common in locker rooms, gyms and schools. "When we screened darwinolide against MRSA we found that only 1.6 percent of the bacterium survived and grew. This suggests that darwinolide may be a good foundation for an urgently needed antibiotic effective against biofilms," said Professor Dr. Bill Baker, whose research team created the darwinolide by chemically rearranging the compounds from freeze-dried sponges in Shaw's lab. Read the press release here.

We’d love to hear what you’ve been reading this week. Please comment below.

Richa Dandona

Partnerships and Operations Manager, Nature Partner Journals, Nature Research