IN THE NEWS

A New Way To Kill Bacteria

A new group of antibiotics with a unique approach to attacking bacteria has been discovered. These may help combat antimicrobial resistance, according to researchers at McMaster University in Hamilton, Ontario, Canada. The new antibiotics blocked infections from drug-resistant Staphylococcus aureus in mice. Bacteria have a wall around the outside of their cells that give them shape, said study first author Beth Culp, PhD candidate in biochemistry and biomedical sciences at McMaster. “Antibiotics like penicillin kill bacteria by preventing building of the wall, but the antibiotics we found actually work by doing the opposite – they prevent the wall from being broken down,” she said. “In order for a cell to grow, it has to divide and expand. If you completely block the breakdown of the wall, it is like it is trapped in a prison and can’t expand or grow.” The discovery comes from a family of antibiotics called glycopeptides that are produced in soil bacteria. The researchers looked into the family tree of known members of glycopeptides and studied genes lacking known resistance mechanisms, theorizing they killed bacteria differently. “This approach can be applied to other antibiotics and help us discover new ones with different mechanisms of action,” said Culp. “We found one completely new antibiotic in this study, but since then, we’ve found a few others in the same family that have this same new mechanism.” The findings were published in the journal Nature on Feb. 12.

By Angela S. Hoover, Staff Writer

What Makes Bat Viruses So Deadly?

It’s no coincidence that some of the worst viral disease outbreaks in recent years – SARS, MERS, Ebola, Marburg and likely the current 2019-nCoV virus – originated in bats. Bats’ immune systems drive viruses to higher virulence, making them deadlier in humans. A new University of California, Berkeley study finds bats’ fierce immune response to viruses could drive viruses to replicate faster, so when they jump to mammals with average immune systems, such as humans, the viruses wreak deadly havoc. This study of cultured bat cells shows their strong immune responses are constantly primed to respond to viruses. Modeling bat immune systems on a computer, the researchers showed when bat cells quickly release interferon upon infection, other cells wall themselves off. This drives viruses to faster production. While this protects bats from getting infected with high viral loads, it encourages these viruses to reproduce more quickly within a host before a defense can be mounted. This makes bats a unique reservoir of rapidly reproducing and highly transmissible viruses. The researchers also caution that disrupting bat habitat appears to stress the animals and makes them shed even more virus in their saliva, urine and feces that can infect other animals. Bat One Health explores the link between loss of bat habitat and the spillover of bat viruses into other animals and humans. “The bottom line is that bats are potentially special when it comes to hosting viruses,” said Mike Boots, a disease ecologist and UC Berkeley professor of integrative biology. “It is not random that a lot of these viruses are coming from bats. Bats are not even that closely related to us, so we would not expect them to host many human viruses. But this work demonstrates how bat immune systems could drive the virulence that overcomes this.”