Former US president Bill Clinton has remained in hospital for a second day, where he has reportedly been recovering from a urological infection.

The 75-year-old was visited by his wife, Hillary Clinton, at the University of California Irvine Medical Center.

He went to the hospital on Thursday after suffering from fatigue and has received both IV antibiotics and fluids, his doctors said.

CNN reported that his doctors believe he has a urinary tract infection that has spread to his bloodstream.

It is unclear when he will be released.

On Friday, President Joe Biden said he has been “exchanging calls” about Mr Clinton and added that “he seems to be, God willing, doing well”.

Mr Biden and Mr Clinton spoke by phone on Friday afternoon, White House spokesperson Karine Jean-Pierre said.

“President Biden and President Clinton look forward to seeing each other again soon,” Ms Jean-Pierre said in a statement. “President Biden wishes President Clinton a speedy recovery.”

Speaking on Thursday, Mr Clinton’s spokesman Angel Ureña said: “He is on the mend, in good spirits and is incredibly thankful to the doctors, nurses, and staff providing him with excellent care.”

Another statement from Mr Ureña quoted Mr Clinton’s doctors, Dr Alpesh Amin and Dr Lisa Bardack, who said the former president has been “administered IV antibiotics and fluids”.

“After two days of treatment, his white blood cell count is trending down and he is responding to antibiotics well,” the doctors said.

“The California-based medical team has been in constant communication with the president’s New York-based medical team, including his cardiologist. We hope to have him go home soon.”

The former US president has seen several health scares since he left the White House in 2001.

Mr Clinton underwent quadruple bypass surgery after he experienced prolonged chest pains and shortness of breath in 2004.

He also went to hospital for surgery for a partially collapsed lung in 2005. In 2010, he had a pair of stents implanted in a coronary artery.