Tetraphase Pharmaceuticals Inc. said Monday that U.S. regulators have given its experimental antibiotic a special designation to speed up the review and approval process and, if it’s approved, give the drug more years without competition.

The drug, eravacycline (eh-RAH’vah-SEYE’cleen), is being developed as both a pill and an intravenous antibiotic for treating different types of infections resistant to multiple drugs.

Such drug resistance has become an increasingly serious problem over the past two decades as bacteria have mutated to become more dangerous and drugmakers have focused their research on more-lucrative treatments for chronic diseases. Resistance increases the cost and duration of treatment — usually in hospitals — and sometimes leads to patient deaths from pathogens including E. coli, MRSA and C. difficile.

Watertown, Mass.-based Tetraphase, which focuses on developing antibiotics to address this problem, said the Food and Drug Administration has designated eravacycline a Qualified Infectious Disease Product, one of the first medicines to get such a designation.

That was granted under 2012 legislation called the GAIN Act, for Generating Antibiotic Incentives Now, meant to encourage pharmaceutical companies to invest in antibiotic research. It gives drugmakers incentives that include expedited review of their testing data and an additional five years on the market without generic competition.

“Antibiotic resistance, particularly among the difficult-to-treat populations with (certain) infections, represents a potential global health crisis,” Guy Macdonald, the company’s CEO, said in a statement.

Eravacylcine, which could become the first product for the company, is a synthetic drug similar to the widely used antibiotic tetracycline.

The company said that in the second half of the year it will begin two late-stage patient tests. Those are needed to win federal approval.