Stories about: bacteria

Scientists find link between increases in local temperature and antibiotic resistance

Image representing the rise of antibiotic resistance
Illustration by Fawn Gracey

Over-prescribing has long been thought to increase antibiotic resistance in bacteria. But could much bigger environmental pressures be at play?

While studying the role of climate on the distribution of antibiotic resistance across the geography of the U.S., a multidisciplinary team of epidemiologists from Boston Children’s Hospital found that higher local temperatures and population densities correlate with higher antibiotic resistance in common bacterial strains. Their findings were published today in Nature Climate Change.

“The effects of climate are increasingly being recognized in a variety of infectious diseases, but so far as we know this is the first time it has been implicated in the distribution of antibiotic resistance over geographies,” says the study’s lead author, Derek MacFadden, MD, an infectious disease specialist and research fellow at Boston Children’s Hospital. “We also found a signal that the associations between antibiotic resistance and temperature could be increasing over time.”

During their study, the team assembled a large database of U.S. antibiotic resistance in E. coli, K. pneumoniae and S. aureus, pulling from hospital, laboratory and disease surveillance data documented between 2013 and 2015. Altogether, their database comprised more than 1.6 million bacterial specimens from 602 unique records across 223 facilities and 41 states.

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Microbial murder mystery solved

Bacteria, pictured in Petri dish culture here, can become resistant to antibiotics - but not killer cells. Why? New research from Boston Children's Hospital helps solve this microbial murder mystery.Immune cells called “killer cells” target bacteria invading the body’s cells, but how do they do this so effectively? Bacteria can quickly evolve resistance against antibiotics, yet it seems they have not so readily been able to evade killer cells. This has caused researchers to become interested in finding out the exact mechanism that killer cells use to destroy bacterial invaders.

Although one way that killer cells can trigger bacterial death is by inflicting oxidative damage, it has not yet been at all understood how killer cells destroy bacteria in environments without oxygen.

Now, for the first time, researchers have caught killer cells red-handed in the act of microbial murder

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Another microbiome perspective: The host holds the leash

Abstract depiction of the microbiome

Most scientists and clinicians accept that the human microbiome impacts a person’s nutrition, immune system function, physical health and perhaps even mental illness, but exactly how or why is not well understood. Now, taking an evolutionary approach, a Boston Children’s Hospital infectious disease researcher suggests the host may play a more active role in controlling the microbiome than previously appreciated.

“I think we need to re-evaluate the way in which we think about the microbiome,” says Seth Rakoff-Nahoum, MD, PhD, a physician-scientist at Boston Children’s in the Divisions of Infectious Diseases and Gastroenterology, whose perspective was published today in Nature.

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Our T-cells have been hiding something: Another way to kill bacteria

Listeria intracellular bacteria infection T-cell immunity granzymes granulysins
Listeria bacteria on a plate. The biology of HIV/AIDS suggests T-cells have a hitherto unrecognized way of killing pathogens like these.

The immune system, despite its immense complexity, really has only a few ways to kill bacteria:

  • Neutrophils and macrophages can capture and digest extracellular bacteria (ones that live free in tissues and the bloodstream).
  • Peptides (protein fragments) can punch holes in bacterial membranes or cross the membranes to disrupt bacterial processes.
  • T-cells can kill cells infected by intracellular bacteria (ones that take up residence within cells).

It’s this last mechanism that I want you to pay attention to. The conventional wisdom has long held that T-cells can only kill intracellular bacteria indirectly by eliminating the cells they’ve infected. But a paper by Judy Lieberman, MD, PhD, of Boston Children’s Hospital’s Program in Cellular and Molecular Medicine, reveals that T-cells have a hitherto unnoticed way of directly killing intracellular bacteria And she only found it because of HIV/AIDS.

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