Dr. Ryan Cirz, a microbiologist and a co-founder of Achaogen, a company whose drug, Zemdri, showed promise in treating U.T.I.s.
Credit: Brian L. Frank for The New York Times

At a time when germs are growing more resistant to common antibiotics, many companies that are developing new versions of the drugs are hemorrhaging money and going out of business, gravely undermining efforts to contain the spread of deadly, drug-resistant bacteria.

Antibiotic start-ups like Achaogen and Aradigm have gone belly up in recent months, pharmaceutical behemoths like Novartis and Allergan have abandoned the sector and many of the remaining American antibiotic companies are teetering toward insolvency. One of the biggest developers of antibiotics, Melinta Therapeutics, recently warned regulators it was running out of cash.

Experts say the grim financial outlook for the few companies still committed to antibiotic research is driving away investors and threatening to […]