Infectious disease specialists are raising the alarm over a variant of the e.coli bacteria that is resistant to most of the antibiotics used to treat bladder infections and could be responsible for more than 3,000 deaths a year.

E.coli ST131, an aggressive strain of multi-drug-resistant e.coli bacteria, may be responsible for as many as 1 million bladder infections a year, according to a recent study conducted by Dr. James Johnson, an infectious disease expert at the Veterans Affairs Medical Center in Minneapolis.