microbiology

A review published in Science estimates that 2 % of rodent species are hyper-reservoirs, hosting and transmitting more than three pathogens to humans, including Lyme disease, Lassa fever and plague. In addition, the authors estimate that 10 % of rodents are reservoirs for one to three pathogens. These are especially so-called synanthropic species - animals that live close to humans and are able to adapt to these environments - such as black rats, Norway rats and house mice.

An international team with Spanish participation has developed a database with the metagenome of bacteria, fungi, and yeasts present in more than 2,500 foods, mostly dairy products, followed by beverages and fermented meats. The authors identified more than 10,800 microorganisms, half of which were previously unknown species. The study, published in Cell, shows that food-associated microorganisms are present in 3% of the adult gut microbiome and 56% of that of newborns.

Researchers at France's National Institute of Public Health have identified priority pathogens for wastewater surveillance during the Paris Olympic and Paralympic Games - to be held from 26 July to 11 August and 28 August to 8 September, respectively. The six pathogens selected, as reported in Eurosurveillance magazine, were poliovirus, influenza A virus, influenza B virus, mpox virus, SARS-CoV-2 and measles virus. Their choice was based on three criteria: analytical feasibility, relevance to the Olympic Games and characteristics of the pathogens, and their value in informing public health policy. In recent weeks, higher than recommended levels of E. coli bacteria have been found in the Seine River, according to the Associated Press.

A new study in mice, published in Science Immunology, challenges the so-called 'hygiene hypothesis', the idea that a contributing factor to allergies is that there is an under-stimulated immune system that has not seen enough exposure to germs from current hygienic conditions. In the research, laboratory mice still developed allergies when exposed to various microbes.

An opinion piece signed by researchers from the Universities of Aberdeen and Nottingham (UK) has outlined some of the inaccuracies, exaggerations and misconceptions they say are taking place around research on the human microbiome. Some of these are curiosities, like the false belief that we have ten bacteria for every human cell. Others are more relevant, such as the fact that many specific associations between the microbiome and disease have not been confirmed in follow-up studies. According to the authors, it is important to raise awareness about myths and misconceptions to avoid unproductive research projects and preserve public confidence in microbiome science. The article is published in the journal Nature Microbiology.

An international team has discovered a new type of molecular fossil in sedimentary rocks from the mid-Proterozoic - which spans from 2.5 billion to 542 million years ago. Protosteroids, a type of lipids found in abundance in those rocks, indicate that eukaryotes were a dominant life form in aquatic environments between 1.6 billion and 800 million years ago, the authors explain in Nature. The finding would confirm the theory of Nobel laureate Konrad Bloch, who predicted the existence of these primordial molecules. 

After the World Cup in Qatar, National Microbiology Centre researcher María Iglesias wonders where the social alarm about an alleged outbreak of MERS came from and takes the opportunity to explain some concepts of the virus and its surveillance.

A study published in PLOS ONE reveals that more than 2,600 bacteria live on average on each floating microfibre in the Mediterranean Sea, belonging to 195 bacterial species. This waste from plastic pollution, textiles and fishing activities, once colonised, smells like food and is consumed by marine animals. Among them, pathogenic Vibrio species have been found, a bacterium that can be a threat to bathing and seafood consumption.

Bacterial infections were the second leading cause of death in 2019. This is according to research published in The Lancet, which estimates that one in eight deaths that year was associated with bacterial pathogens. Five of these - S. aureus, E. coli, S. pneumoniae, K. pneumoniae and P. aeruginosa - accounted for more than half of all bacteria-related deaths.

The rise in cases of asthma, allergies and digestive tract diseases, among others, could be linked to changes in the microbiome. US researchers are propose to combat this trend by having us all save samples of our own gut microbiota when we are young and healthy, for later use in an autologous faecal microbiota transplant.