Baltimore’s problem with Legionella bacteria in its courthouses continues, as elevated levels of the dangerous bacteria were again detected in the water at three buildings on Friday, the mayor’s office announced.

The affected court buildings — the Baltimore City District Court on East Fayette Street, along with the Clarence M. Mitchell Jr. and Elijah E. Cummings courthouses on Calvert Street — were previously closed for two days in December for remediation efforts following positive tests for Legionella, which can cause Legionnaires’ disease, a serious form of pneumonia.

Legionella bacteria can grow and spread in water systems, and exposure to the bacteria can occur when people breathe in mist that contains it, according to the Centers for Disease Control and Prevention.

In response to the latest positive tests, the city is conducting mitigation efforts this weekend, per the mayor’s office’s announcement.

Several Baltimore government buildings have been battling the Legionella bacteria in recent months. In November, it was detected at the State Center complex, which led to a temporary closure and raised concerns among the unions representing thousands of State Center workers.

“It’s really frustrating and deflating to the workers,” Todd Reynolds, political coordinator for AFT-Maryland, said at the time.

Then in December, City Hall and the Abel Wolman building, along with two city District Court buildings (5800 Wabash Ave. in Northwest Baltimore and 700 E. Patapsco Ave. in South Baltimore), also tested positive for the bacteria.

The city, which cited the courthouses’ aging plumbing systems as a likely contributor to the bacteria detection, said it will install “additional mechanical water management systems” to prevent bacterial growth in the coming weeks to further address the problem.

Baltimore’s health department has not received any confirmed reported cases of Legionnaires’ disease related to the elevated levels of the bacteria in city buildings, according to the mayor’s office.