Six babies infected with MRSA at a Pittsburgh hospital are stable, according to hospital officials.

That's after a dozen cases of MRSA were reported at UPMC Children's Hospital.

An Allegheny Health Department epidemiologist said two in 100 people have MRSA in their nose or on their skin, and it only occasionally develops into infection.

UPMC is saying all six babies in the Children's Hospital Neonatal Intensive Care Unit (NICU) who tested positive for the MRSA bacteria are expected to be okay.

"They are not demonstrating signs of clinical infection such as a fever, such as rashes," said Diane Hupp, chief nursing officer.

The six staff members who tested positive for MRSA are not allowed back to work until they show a negative test for the bacteria.

Meanwhile, the hospital is still running a battery of tests, including some to determine where the MRSA came from.

Doctors believe at least one person got MRSA from a visitor, but it's unclear if that strain of MRSA bacteria was transmitted to all 12.