A Clever New Approach to an Old Problem

Antibiotic resistance is one of the most pressing threats in modern medicine. Drug-resistant bacteria already contribute to nearly 5 million deaths worldwide each year, and the World Health Organization warns that number could climb to 10 million annually by 2050 if new solutions don't emerge.

Now, scientists at Cold Spring Harbor Laboratory (CSHL) and Scripps Research have found a way to breathe new life into one of medicine's oldest and most important last-resort antibiotics — vancomycin.

Instead of designing a brand-new drug from scratch — a process that takes over a decade and costs billions — the researchers took a different approach. They paired vancomycin with a small molecule called pghi-4, which blocks a bacterial enzyme that had been helping superbugs resist treatment.

How It Works

The target is an enzyme called secreted antigen A (SagA), which vancomycin-resistant Enterococcus faecium (VREfm) — one of the most dangerous hospital-acquired superbugs — uses to remodel its cell wall. By reinforcing its outer defenses, the bacteria had become effectively untreatable with vancomycin alone.

Pghi-4 inhibits SagA, stripping the bacteria of this defense. In laboratory tests, the combination reduced the amount of vancomycin needed to kill VREfm by up to 8-fold. The effect held across multiple clinical isolates and significantly reduced bacterial burden in infected mice.

"To demonstrate you can pharmacologically target this enzyme family is a big step forward," said Professor Howard Hang of Scripps Research.

First-in-Class Discovery

SagA belongs to a family of cell-wall-remodeling enzymes called NlpC/P60 peptidoglycan hydrolases — an enzyme family that no drug had ever successfully targeted before. Pghi-4 is the first-ever inhibitor of its kind, opening an entirely new category of antibiotic adjuvants: compounds that don't kill bacteria directly but disable their specific resistance mechanisms so existing antibiotics can work again.

"This discovery came from fundamental chemical research," said Professor Joshua Moses of CSHL, whose lab first identified pghi-4 in 2020. **"Reaction development led to the discovery of the first inhibitor of an important enzyme involved in antibiotic resistance."**

What Comes Next

The research was published in Nature Communications on June 16, 2026, with the public announcement on July 22. While the findings are still preclinical, the team is already developing more potent second-generation derivatives of pghi-4 and exploring whether the approach can be extended to other resistant bacteria, including drug-resistant Staphylococcus aureus.

For patients and healthcare workers, this is promising early-stage science — years from clinical use, but addressing a genuine and growing public health crisis through a mechanism that is entirely new.

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