It comes after two Shepparton Villages staff members returned positive COVID-19 tests this weekend.
Shepparton Villages interim chief executive officer Greg Pullen said the Maculata Place resident had her test fast-tracked after she was displaying symptoms around the time initial testing took place.
"I have already spoken to the relatives and the resident has been informed," Mr Pullen said.
"Under the advice of authorities, the resident is being isolated and treated at Maculata Place."
Mr Pullen said the test results for remaining Maculata Place residents should return within the next 24 hours.
"Testing and results are out of our control," he said.
"Families and residents will be notified of the result as soon as we receive them.
"All residents have been isolated within their own room since Thursday and staff have been utilising full personal protective equipment (PPE) since then as well.
"Supplies of PPE remain adequate as are supplies of other items, such as food and linen."
Mr Pullen said the atmosphere was "calm" at Maculata place, and residents were "responding well" to the circumstances.
"We will continue to keep residents, families and staff informed," he said.
Mr Pullen said all 19 residents at Bertram House, where the first staff member who tested positive mostly worked, had returned negative COVID-19 tests, as had all other close contacts of the first staff member at Maculata Place.
He said the second staff member who tested positive was believed not to have worked while infectious.
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