Maryland public health officials said yesterday that three of the state’s four pending cases of E. coli O157 illness are not linked to a nationwide outbreak caused by bad spinach.

Officials told the Washington Post they continue to investigate the death of an 86-year-old Hagerstown woman and hope to receive test results within a week. But those results might prove inconclusive, because of problems associated with a sample.  All told, only three of the state’s 10 cases have conclusively been linked to the bad bagged spinach from California.

The nationwide outbreak, which has infected 175 people in 25 states, has been traced to fresh spinach from three counties in and around Salinas Valley in California, according to the Centers for Disease Control and Prevention. Among those ill, the CDC said, 53 percent were hospitalized; 16 percent developed a type of kidney failure called hemolytic uremic syndrome; and an adult in Wisconsin died. Two other deaths — a child in Idaho and the Hagerstown woman — might be linked to the bad spinach.