A second Hamilton hospital has declared an outbreak of C. difficile. (Jessica Young/CBC)

A second C. difficile outbreak has been declared at a Hamilton hospital, this time in the surgical trauma unit of Hamilton General.

There have been four confirmed cases of C. difficile at the Hamilton Health Sciences site, three in the unit known as 6 South. On Saturday, St. Joseph's Healthcare also declared a C. difficile outbreak. Eleven patients currently are isolated with the infection.

The 6 South unit remains open, and there are no other symptomatic patients under investigation at Hamilton General, the hospital said in a statement.

There have been no deaths at Hamilton General of patients with C. difficile as a result of the outbreak, said Dr. Dominik Mertz, the hospital's medical director of infection control and prevention.

The outbreak in the surgical trauma unit at Hamilton General is likely unrelated to the outbreak at St. Joseph's, Mertz said.

"We don't see any links currently," he said. "It's not like we have an influx of patients from St. Joseph's and vice versa."

The hospital has implemented prevention and control measures to try to prevent the spread of the disease. It is not unusual for hospitals the size of Hamilton General to have cases of C. difficile at any given time, he said.

"When we see a cluster of cases, we become even more vigilant than usual, ramping up our cleaning procedures, hand-washing practices, and ensuring that antibiotics are used appropriately. Infection control is always our top priority."

Strategies include:

• Promoting good hand hygiene among staff, patients and visitors.
• Isolating C. difficile patients in rooms that are cleaned twice daily.
• Heightened cleaning procedures in the unit.
• Early detection and intervention by the infection prevention and control team.
• All staff and/or visitors to affected patients wear protective equipment.

One patient with C. difficile at St. Joseph's Healthcare's Charlton campus died on July 11. But a preliminary review shows that the infection "is not thought to be highly significant in that patient's death," Winnie Doyle, vice-president of clinical programs, told CBC News on Monday afternoon.

The Hamilton General surgical trauma unit has more than 20 patients at any given time. When three patients are diagnosed with C. difficile, an outbreak is declared, Mertz said.

Hamilton's public health department declares C. difficile outbreaks, looking at criteria such as the number of patients in a unit, the number of C. difficile cases typically in that facility and how quickly new cases are diagnosed, said Hamidah Meghani, Hamilton's associate medical officer of health.

In 2011, there were 34 outbreaks declared at hospitals in the province, Meghani said.

"Many hospitals will have an outbreak at some point," she said. "It's not an uncommon thing."