St. John's Riverside Hospital officials say the MRSA infection that had been detected in seven newborn babies was likely brought into the maternity ward from the outside by a staffer.

Hospital officials, however, have yet to pinpoint the exact source of the staphylococcus infection, which ended up causing skin rashes on seven infants in the nursery at St. John's.

"We're actually fairly certain that there is no individual who touched all seven, and we're confused,? says St. John?s President Jim Foy.

The hospital tested 100 employees who work on the third floor of the medical facility, and four of them tested positive for the same strain of MRSA that was found in the newborns.

"More likely that this is attributable to an individual who brought this into the hospital in some way, had contact sufficiently with these infants and transmitted MRSA probably through skin contact,? says infectious disease specialist Dr. Berkey.

The first case of MRSA appeared Sept. 24, and over the past week three more babies have been infected with the Superbug. Hospital officials say the children had been treated for minor rashes and cured, but News 12 Westchester learned that one of the babies with a severe case of the infection had been transported to Westchester Medical Center.

On Wednesday, hospital administrators said the maternity ward had been thoroughly cleaned. In addition, the hospital limited visitation hours and introduced new rules requiring all visitors and employees to sanitize their hands before entering the nursery.