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Many diseases related to bacteria, such as inflammatory bowel disease or colorectal cancer, are associated with an overgrowth of gut bacteria considered 'bad'. However, a study published in the journal Cell suggests that changes in microbial load, rather than the disease itself, could be the driving factor behind the presence of these harmful species associated with pathologies.

The Royal Swedish Academy of Sciences has awarded the Nobel Prize in Chemistry 2024 on the one hand to David Baker for computational protein design, which makes it possible to construct proteins with functions not present in nature. On the other hand, jointly to Demis Hassabis and John M. Jumper of Google DeepMind, for the development of AlphaFold2, which allows the structure of the 200 million known proteins to be predicted at high speed. 

Research has identified 31 biomarkers in the gut microbiota of children that are associated with autism spectrum disorder (ASD) and could have diagnostic value. The gut microbiota includes bacteria, viruses, fungi and archaea. The team replicated the results, published in Nature Microbiology, in three cohorts and analysed faecal samples from more than 1,600 children and children in total, with and without ASD, in China.

After the first year of life, the father's contribution to his baby's microbiota is comparable to the mother's contribution, whether born vaginally or by caesarean section, says a study published in Cell Host & Microbe. In addition, faecal microbiome transplants from the mother to her baby can restore the microbiome in the case of caesarean birth, says the study, which included 74 babies and involved Spanish participants. 

The risk of developing resistant bacteria is higher in some people, such as those who have to take long-term antibiotics after organ transplantation. To try to reduce them, a phase 1 clinical trial has performed a fecal transplant on 10 people who had previously received a kidney transplant and had resistant bacteria. The fecal transplants accelerated decolonization, shortened the time it took to test negative for multidrug-resistant organisms, and, according to the authors, may also "reduce the recurrence of infections." The results are published in the journal Science Translational Medicine.

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.

Faecal microbiota transplantation can be administered by oral capsules, colonoscopy or rectal enema, among other routes. Two meta-analyses evaluate its benefits and side effects for treating two types of disease. The first focuses on recurrent infections with Clostridioides difficile, a bacterium that can cause very severe diarrhoea; it includes six studies in Europe and North America involving 320 adults and concludes that in immunocompetent people, faecal transplantation is more effective than antibiotics. The second focuses on irritable bowel diseases, such as ulcerative colitis and Crohn's disease; it includes 12 studies with 550 participants and has less clear results.

Two studies have found changes in the microbiome of patients affected by chronic fatigue syndrome. In particular, they have found a decrease in both butyrate and certain bacteria that produce butyrate. Butyrate is a factor related to the protection of the intestinal barrier and appears to play a role in the regulation of the immune system. Both papers are published in the journal Cell Host and Microbe.

An international team including researchers from Spain has analysed the level of exchange of microbial strains between different generations (vertical transmission) and between people who share a household or are close contacts (horizontal transmission). The analysis, published in the journal Nature, is based on about 9,700 microbiome samples from the faeces and saliva of people with different lifestyles from countries. According to the research, the transmission of bacteria is more frequent for the mouth microbiome than for the gut microbiome among people living together.   

A metagenomic comparison of the infant gut microbiome of industrialised and non-industrialised populations reveals robust differences that researchers say are lifestyle-dependent. The research involved samples from infants of Hadza, a group of modern hunter-gatherers living in Tanzania, and is published in the journal Science.