Antibiotic-resistant bacteria pose an ever-growing global threat, currently claiming the lives of at least 23,000 people in the United States each year. Research published this year shows that certain strains of a deadly, multidrug-resistant bacterium have now developed resistance to the last-resort antibiotic colistin.

That’s worrisome news, but scientists at Harvard University have discovered a weakness in the protective covering of most bacteria that could offer a glimmer of hope in the battle against superbugs.

A shell, or wall, that encapsulates bacteria serves to keep them structurally intact and safe from toxins, drugs, and viruses that could kill them. Many current antibiotics work by disrupting the proteins that build this protective shield, but superbug proteins have adapted and many of those drugs can no longer stop the shell-building process.

In the study published in the April 5 issue of Nature, the Harvard research team discovered a weak spot—an externally accessible, pocketlike cavity—in RodA, a wall-building protein present in almost all bacteria.

When the researchers mildly altered these pockets in two of the most common disease-producing bacteria, RodA became disabled and the bacterial cells burst.

If scientists can develop new drugs that bind to these pockets, they would disable the protein in the same way. “That would, in essence, crack the wall, weaken the cell and set off a cascade that eventually causes it to die,” David Rudner, co-leader of the study, said in a statement.

Because most bacterial species contain RodA, a drug made to disrupt the protein should work against many different kinds of harmful bacteria.

Touchy feeling

Researchers at the California Institute of Technology recently developed a method to help a man, paralyzed from the shoulders down, feel the natural sensations of touch and movement in his arm.

In their study, published on April 10 in eLife, the researchers implanted tiny electrodes into the patient’s somatosensory cortex, the region of the brain that governs the sense of touch, movement, and the body’s position in space. They then stimulated the electrodes with very small pulses of electricity.

The patient reported feeling sensations such as squeezing, tapping, and a sense of upward motion, depending on the frequency, magnitude, and location of the stimulation. The researchers believe the same technique could one day allow paralyzed people using prosthetic or robotic limbs to feel physical sensations through sensors placed on the devices, making the prostheses feel more like a normal part of the body. —J.B.

Dust observed

Thanks to a powerful planet-finding instrument at the European Southern Observatory’s Very Large Telescope in Chile, astronomers can view the dusty disks surrounding nearby stars in more detail than ever before.

The dim, reflected light of the disks is difficult to see because of the brightness of their parent stars. But the telescope instrument allows scientists to block the starlight, making the regions around them visible.

The new images from the telescope show the disks, made of gas, dust, and rocky matter, come in a surprising range of shapes and sizes, with bright rings, dark rings, or even a shape like a hamburger.

Many scientists think the disks are responsible for forming planets around their host stars, though some dispute that theory. —J.B.