ROME (AP) - Pope Francis showed a “marked improvement” Thursday after being given intravenous antibiotics for a bronchitis infection and could be released from the hospital in the coming days, the Vatican and his doctors reported.

The 86-year-old pontiff, who had part of one lung removed as a young man, ate breakfast, read the newspapers, rested and worked from his hospital room at Rome's Gemelli hospital, according to Vatican spokesman Matteo Bruni.

An additional update provided late Thursday by doctors revealed Francis had been diagnosed with bronchitis. The infection “required the administration of antibiotic therapy on an infusion basis which produced the expected effects with a marked improvement in his state of health,” the doctors' statement said.

“Based on the expected course, the Holy Father could be discharged in the coming days,” it concluded.

The timeframe brought into question Francis' participation in Palm Sunday Mass in St. Peter's Square this weekend, as well as his presence during Holy Week activities. They include Holy Thursday, Good Friday, the Easter Vigil and Easter Sunday on April 9.

Francis was hospitalized Wednesday after having trouble breathing in recent days.

It was the first time he had back to Gemelli since he had 33 centimeters (13 inches) of his colon removed and spent 10 days there in July 2021.

Despite his absence, the Holy See was abuzz with activity Thursday: Two Vatican offices issued a historic statement repudiating the “Doctrine of Discovery,” the legal theory backed by 15th century papal bulls that legitimized the colonial-era seizure of Native lands and form the basis of some property law today.

And there was continued fallout over the sudden resignation of a founding member of the pope's sex abuse prevention board, with Boston Cardinal Sean O'Malley pushing back against Rev. Hans Zollner's critiques in his remarkable resignation statement issued the previous day.

He said soon after the intestinal surgery that he had recovered fully and could eat normally. But in a Jan. 24 interview with The Associated Press, Francis said his diverticulosis, or bulges in the intestinal wall, had “returned.”

Francis has used a wheelchair for over a year due to strained ligaments in his right knee and a small knee fracture, though he had been walking more with a cane of late.

Francis has said he resisted having surgery for the knee problems because he didn't respond well to general anesthesia during the 2021 intestinal surgery.