UNITED NATIONS — Diplomats and heads of state addressed a dizzying array of issues at the UN Wednesday with topics ranging from stopping the health threat of drug-resistant “super bugs” to ending the killing on the battlefields of Syria.

As the second day of the annual General Debate got underway, national leaders delivered their formal speeches in the gilded General Assembly hall, perhaps the most visible spectacle of the annual gathering.

But the focus shifted to meetings and panels on water and sanitation, the death penalty, a nuclear test ban treaty, adequate opportunities for employment and, most notably, a Security Council consultation on several setbacks in Syria.

The talks on Syria, attended by foreign ministers and the top leaders of some nations, discussed the most recent incidents, including a deadly attack on a humanitarian convoy Monday and an airstrike Saturday on Syrian troops.

Two unfortunate developments followed and formed the backdrop for spirited talks Wednesday: The weeklong cessation of hostilities was scuttled and the UN suspended humanitarian deliveries of food, medicine and water to besieged populations now enduring 5-1/2 years of a war that the UN’s humanitarian chief once called “breathtakingly savage.”

The earlier attack has been attributed to, but not acknowledged by, the Syrian-Russian alliance, while blame for the airstrike on Syrian troops went to forces led by the United States, which has acknowledged it as a mistake.

“The attack on a UN-Syrian Arab Red Crescent humanitarian convoy two days ago was an outrage, resulting in several casualties and forcing the UN to suspend aid operations,” said UN Secretary-General Ban Ki-moon, at the meeting, where he also urged the parties to resume the cease-fire. “I am looking at options for vigorously investigating this and other similar atrocities against civilians. I am also concerned about the earlier attack in Deir al-Zour in which dozens of lives were lost. I take note of the rapid acknowledgment by the U.S. of this strike and look forward to more information. We must remain determined that the cease-fire will be revived.”

Diplomats, including U.S. Secretary of State John Kerry, who echoed the UN chief’s call for a cease-fire and pushed for a ban on aircraft in the areas of aid delivery, proceeded to trade barbs over who was most responsible for sabotaging the effort to bring peace to Syria.

In another part of the UN complex, health ministers and officials of UN-affiliated agencies shared ideas and concerns about how to slow the advance of bacteria that are becoming evermore resistant to antibiotics used to combat them.

Margaret Chan, director general of the World Health Organization, said antimicrobial resistance, also known as AMR, is “a global crisis and some call it a slow-motion tsunami. . . . The situation is bad and it’s getting worse.”

Chan and others pointed out a paradox of fighting infections: the more people use the drugs that kill bacteria, the more savvy the bacteria become in mutating, to blunt the effects of the drugs. Overuse accelerates the ability of bacteria to adapt and find new ways to survive, eventually rendering the drugs ineffective. Still, underuse of the antibiotics allows diseases to spread.

Common ailments treated with antibiotics, like a skinned knee or gonorrhea, may become deadly if humans don’t win what public health officials view as a race against time.

Pharmaceutical firms, Chan said, are less likely to research and develop antibiotics because the profit margins for those drugs are low, compared with the yield for other drugs due to vaccines and antibiotics being taken for a short period of time while maintenance drugs may be used over a lifetime.

In a statement, Pfizer Inc., a global pharmaceutical manufacturer headquartered a block away from the UN, said it was reinvesting in antibiotics and vaccines after scaling back research and development of them a few years ago.

“As a signer of both the Industry Roadmap and the Declaration on AMR, Pfizer is proud to be a part of these unprecedented steps taken by our industry to help address the growing public burden of antimicrobial resistance,” said Freda Lewis-Hall, chief medical officer. “With these commitments by industry, we call on governments and the public health community to take further action to strengthen public health systems and support measures that will enable continued innovation in the development of new antibiotics and vaccines.”