Maryland health officials are reporting the state's first two known cases of swine flu resistant to Tamiflu.

Johns Hopkins Hospital in Baltimore announced Wednesday that the two patients were treated there and have been discharged.

The hospital says the federal Centers for Disease Control and Prevention and Maryland health officials confirmed the patients had a drug-resistant form of the virus.

Last month, health officials in North Carolina announced four patients at a one hospital tested positive for Tamiflu-resistant swine flu, the biggest cluster seen in the U.S.

Tamiflu is one of two common swine flu treatments, and health officials have been watching for signs of resistance to the drugs. More than 50 resistant cases have been reported since April, including 21 in the U.S.