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Tag: antibiotics (page 1 of 4)

04.10.2016

yvette fay francis-mcbarnette

The New York Times ran an obituary commemorating the life of Dr. Yvette Francis-McBarnette. I had never heard of her but found her life story inspirational, especially for budding minority scientists.

Yvette Francis McBarnette

Dr Yvette Fay Francis-McBarnette

Yvette immigrated to New York City from Jamaica with her parents and at 14 years old she began studies at Hunter College. After completing a bachelor’s degree in physics, she began a master’s degree in chemistry at Columbia University. Then she went on to be come only the second black woman to earn a medical degree from Yale University.

As a physician, she made tremendous progress in studying and treating sickle cell anemia in young patients. Sickle cell disease deforms the shape of red blood cells, making them rigid and harder to pass through capillaries. It can lead to oxygen deprivation in organs and tissues and also severe pain. The disease is more prevalent in black and Mediterranean populations.Yvette pioneered new antibiotic treatments for the disease and established the Foundation for Research and Education in Sickle Cell Disease. And she did all of this work during the 1950s and 60s when women had fewer opportunities and less support than exists today, doubly so for black women.

 

06.06.2015

antibiotic advances

Staph aureus

Drug resistant Staph aureus

Over on nature.com, Sara Reardon provides a brief rundown on different alternatives to traditional antibiotic treatments. These alternatives are among some of the most promising solutions to growing antibiotic resistance. Sara mentions peptides, phages, metals and gene editing techniques. Phages have been used clinically for many years especially in Eastern Europe. And metals like silver and copper have been used as antibiotics since at least the 4th century B.C. Silver in particular causes bacteria to act like zombies and kill other live bacteria after they’ve been treated.

Antibiotic peptides are commonly isolated from the skin of frogs, and also in fungi. These peptides are typically 10–50 amino acid residues long and have many cationic residues. They can act in multiple ways, but most permeabilize and disrupt cellular membranes causing bacterial contents to leak out of the cell.

Gene editing is gaining popularity as scientists makes continued improvements to CRISPR technologies.  Bacteria usually use CRISPR to develop resistance to phages and viruses, but scientists are engineering ways to use this to make bacteria attack themselves. As the technology develops, some scientists believe antibiotic CRISPR systems have the potential to be much better than traditional antibiotic treatments.

Taken as a whole, development on all these fronts signals that research on new antibiotics will continue to progress, even as traditional small molecule antibiotics are becoming harder to find.

11.22.2013

bacteria aid chemotherapy response

Bacteria

Image from Discover Magazine

In the latest edition of Science magazine, two papers describe how bacteria in the stomach and intestines can help improve chemotherapy outcomes – at least in mice.

In the first study, Iida et al. dosed a group of mice with antibiotics for a prolonged period before exposing them to cancer therapies. The antibiotic treatment eliminated their populations of gut microbes. Tumors in these mice did not shrink in response to the therapy as they did in the control group, which received no antibiotics. Similarly, mice brought up in a sterile environment also had showed no chemotherapeutic response. Mice brought up in sterile environments never develop diverse microbial populations since they don’t get exposed to them. Mice lacking the bacterial populations don’t show the production of a protein called tumor necrosis factor that generates the tumor killing response in the organism.

The researchers also found that when the chemotherapeutic drug oxaliplatin was administered to mice who were germ-free or given antibiotics, the cancer killing response was much weaker and ineffective when compared to the control.

The second group of researchers performed similar studies with a chemotherapy drug called cyclophosphamide, or CTX. CTX is used to treat breast cancers and some brain cancers and works by increasing the number of Th17/Th1 immune cells. As in the previously mentioned study, mice that were dosed with antibiotics or that were raised in sterile environments exhibited a weaker anti-tumor response to the CTX.

Results from both of  these studies indicate that microbes influence anti-tumor responses. So what does that mean for cancer patients? Dr. Zitvogel, who led one of the research teams, is taking considering the implications saying “We are going to be very careful about prescribing antibiotics during chemotherapy.” Dr. Trinchieri, who led another team, says that we should be cautious about extrapolating any results from mice to humans. He also suggests studies in healthy humans examining the effect of gut bacteria on immune cell production. His sentiment would likely be seconded by most scientists. As a matter of fact, Science magazine has another article in the same issue titled “When Mice Mislead”.

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