While Gov. Gavin Newsom issued an urgent call Monday for retired healthcare workers and students nearing graduation to join in caring for an expected surge of coronavirus patients, officials scrambled to contain a rash of outbreaks in nursing homes and find space for thousands of new hospital beds.

Authorities in Los Angeles County moved to isolate and quarantine patients at 11 assisted living facilities, up from just three on Friday. And nine employees and two patients tested positive at the 780-bed Laguna Honda Hospital and Rehabilitation Center in San Francisco, prompting the Centers for Disease Control and Prevention to send physicians and epidemiologists to manage a potentially devastating outbreak of COVID-19.