Thames study: Rivers can be a major source antibiotic resistance

Rivers and streams could be a major source of antibiotic resistance in the environment.

The discovery comes following a study on the Thames river by scientists at the University of Warwick's School of Life Sciences and the University of Exeter Medical School.

The study found that greater numbers of resistant bacteria exist close to some waste water treatment works, and that these plants are likely to be responsible for at least half of the increase observed.

Antimicrobial resistance is one of the largest threats to human health for a century, the researchers argue. Increasingly large amounts of antibiotics are released into the environment through both human and agricultural use, with surface run off from farming activities (including fertiliser and animal slurry) washed straight into rivers after heavy rainfall.

Co-lead on the research, Professor Elizabeth Wellington of the University of Warwick, said: "Antibiotic resistance naturally occurs in the environment, but we don't yet know how human and agricultural waste is affecting its development. We've found that waste water discharges effect resistance levels and that improvements in our treatment processes could hold the key to reducing the prevalence of resistant bacteria in the environment.

"We found antibiotic resistance in the group Enterobacteriaceae which includes gut bacteria and pathogens."

Published in Nature's The ISME Journal, the study has also shown that different types of waste water treatment plant release varying amounts of resistant bacteria. Professor Wellington explains: We produced a model based on our data which showed that there was a big difference between secondary and tertiary activated sludge plant where the latter resulted in a predicted 100-fold decrease in resistance levels.

Study co-lead author, Dr William Gaze of the University of Exeter Medical School said: "Our research has shed further light on links between environmental pollutants and antibiotic resistance. It has allowed us to uncover an association between a number of compounds -- such as zinc, phosphorus and silicon -- and antibiotic resistance. We think those bacteria that have developed to survive in environments rich in metals may also possess antibiotic resistance mechanisms -- highlighting the complexity of this global issue."

The researchers analysed water and sediment samples from 13 sites across the Thames river catchment and developed detailed models to predict the distribution of antibiotic resistant bacteria.

The team also found that several other factors affected the prevalence of antibiotic resistance, such as changes in rainfall and land cover. For example, heavy rainfall at a point surrounded by grassland raised resistance levels; whereas a heavy rainfall at a point surrounded by woodland reduced the levels seen.

The findings have allowed the research team to develop a robust model that will predict the level of antibiotic resistance in other catchments, without the need for detailed water sampling.

Increased levels of antibiotic resistance in the aquatic environment could lead to increased risk of human exposure. More research is required to fully understand the risk posed via this route and the possible implications for public health.

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The above story is based on materials provided by University of Warwick . Note: Materials may be edited for content and length.

Bacteria protect intestinal tumor model from being killed by immune cells

Bacteria that are commonly found in the mouth are often abundant in patients with colon cancer, but the potential role these microbes play in tumor development has not been clear. A study published by Cell Press February 18th in the journal Immunity reveals that the oral pathogen Fusobacterium nucleatum protects a variety of tumor cells from being killed by immune cells. The findings could open new avenues for the treatment of cancer in human patients.

"Certain bacteria have previously been shown to fight cancer, so the surprising finding of this paper is that bacteria such as Fusobacterium nucleatum can grant tumors an anti-immune defense mechanism," says co-senior study author Ofer Mandelboim, PhD, of The Hebrew University Hadassah Medical School. "Blocking the interaction between these bacteria and immune cells might improve anti-tumor immunity both in general and with regard to colon cancer in particular."

Immune cells called natural killer cells defend the body against a variety of health threats, including viruses and parasites. These cells can also kill tumors, but cancer cells have evolved ways to evade this immune response. In the early 1890s, a surgeon named William Coley recognized that certain bacteria can enhance anti-tumor immunity, and he even used bacterial extracts to successfully treat cancer patients. But the relationship between bacteria and tumors is complex, and until now, it was not known whether other types of bacteria that are common in cancer patients could have the opposite effect: protecting developing tumors from immune cell attack.

To address this question, Mandelboim teamed up with co-senior author Gilad Bachrach of the Hebrew University-Hadassah School of Dental Medicine to study how the anti-cancer activity of natural killer cells might be affected by Fusobacterium nucleatum--an oral pathogen that has been linked to periodontal diseases and is also present in human colorectal tumors.

They found that this bacterium protects a variety of human tumor cells from destruction by human natural killer cells. Moreover, this immune evasion depends on the binding of a bacterial protein called Fap2 to an immune cell receptor called TIGIT. "The implications are that if we either remove the Fusobacterium nucleatum bacteria from the tumors or inhibit TIGIT with antibodies, we might enable immune cells to kill the colon tumors more efficiently," says first author Chamutal Gur of The Hebrew University Hadassah Medical School.

The researchers now intend to test whether this bacterium is found in other types of tumors and whether additional bacteria that colonize tumors affect the activity of immune cells. They also plan to study Fap2-TIGIT interactions in more detail and develop ways to block these interactions. "Because Fusobacterium nucleatum specifically targets tumors, it may be possible in the future to use a Fap2-deleted Fusobacterium nucleatum to guide therapeutic agents to kill the tumors," Mandelboim says.

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The above story is based on materials provided by Cell Press . Note: Materials may be edited for content and length.

Mapping the gut microbiome to better understand its role in obesity

Several recent science studies have claimed that the gut microbiome--the diverse array of bacteria that live in the stomach and intestines--may be to blame for obesity. But Katherine Pollard, PhD, a senior investigator at the Gladstone Institutes, says it is not that simple.

Dr. Pollard will be presenting at the Obesity and Microbiome symposium at the AAAS Annual Meeting in San Jose, CA on Friday, February 13, 2015 at 3:00 PM PT.

Using powerful computational tools, Dr. Pollard and her team have reanalyzed several previous studies and revealed that there is no significant relationship between body mass index (BMI) and the types of microbes in one's gut. In fact, her lab found that there was greater variability in gut bacteria between the different studies than between the lean and obese individuals within each study.

Instead, Dr. Pollard thinks that it is the genetic make-up of the different strains of bacteria that is most important. This is because the DNA in bacteria can vary wildly. For example, while the genomes of two humans may only differ by 0.1%, two strains of the same bacteria can vary by to 30%--similar to the variation between human and mice genomes! What's more, the differences in the bacterial genomes are often important pieces that are involved in metabolism or the processing of sugar and fat.

Besides reflecting important functional changes in bacterial genomes, losses and gains of genes also affect genome size. When microbiomes are studied using metagenomics--sequencing their total DNA--differences in bacterial genome size can bias the estimation of the proportion of each gene in the sample. By developing a computational shortcut to rapidly estimate genome size using statistical modeling, Dr. Pollard's team has been able to improve the accuracy of microbiome studies.

"It's not enough to say what type of bacterial species are present, because that doesn't tell you what they're doing," explains Dr. Pollard. "Since two strains of the same species can have such different genomes, you really need to know what genes are there and what role they play in order to link someone's gut microbiota to BMI or disease."

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The above story is based on materials provided by Gladstone Institutes . Note: Materials may be edited for content and length.

The Joseph Grado Inventions That Shaped the Way We Hear Music

Late last week, one of the great innovators in consumer audio passed away. The loss of Joseph Grado is felt deeply by all of us who love and care about great audio gear.

The company Joseph started, Grado Labs, continues to be a huge name in the hi-fi audio industry. The Grado of today makes several different styles of headphones, from world-class high-end models to sub-$100 consumer models, as well as headphone amplifiers and phono cartridges for record players. It has always followed Joseph’s original vision of making products that try to reproduce music as faithfully and accurately as possible, so you hear your favorite songs the way they were meant to be heard.

Flip through the photo gallery above to see some of Joseph Grado’s most important and enduring contributions to the world of quality audio. Expand the gallery to full-size to see the large versions of the photos and illustrations.

“My uncle, foremost, was a lover of music,” says John Grado, Joseph’s nephew and current President & CEO of Grado Labs. He shared some family photos with us, along with some product photos showcasing the company’s innovations, which we’ve collected above. One picture in particular highlight’s Joe’s love of music: the illustration of him in costume as Otello. He was a tenor, and a big fan of the stage.

But even though Joseph Grado displayed obvious talent and ambition early in life, Joe never planned a future in audio. In fact, when he began working in the field, he scarcely knew what a decibel was, and he certainly wasn’t well-acquainted with the finer points of audio component design.

Joseph was watchmaker by trade, and while he didn’t have much experience in the audio world, he had a passion for perfection and an ear for sound. It was at the insistence of Saul Marantz (the mind behind Marantz pre-amps) that Joseph met with Sherman Fairchild, who wanted his “expert” advice on improving the manufacturing process of his phono pickups. Joe obliged, and Fairchild all but offered him a job on the spot.

Grado left his watchmaking position at Tiffany & Co. to helm Fairchild’s struggling hi-fi operation and used his talents to design and manufacture quality phono pickups. Not long after, in 1953, Joe struck out on his own to begin making the very first Grado Labs cartridges in his kitchen in Brooklyn. Sixty-two years, almost 50 patents, and dozens of products later, Grado Labs is one of the foremost names in the audiophile world.

Among his most important patented inventions is the stereo moving-coil cartridge, a new (in 1959, anyway) design for the record player stylus that offered a significant improvement in audio fidelity. Joe Grado also created the HP-1000 headphones, an iconic design that’s not only still sought-after by collectors, but one which still technically and visually informs all of the modern headphone designs Grado makes today.