Why is the FDA curbing antibiotic use in animals?

CBS News chief medical correspondent Dr. Jon LaPook and CBS News contributor Dr. Holly Phillips joined "CBS This Morning: Saturday" to discuss the major medical stories of the week.

The Food and Drug Administration announced what will be a major change in the U.S. food supply. The use of antibiotics will be rolled back in beef, pork and poultry. The goal is to reduce the development of new, drug- resistant bacteria that have become a major public health threat.  

For decades farmers have added antibiotics to animal feed to stimulate growth in poultry, cattle and pigs, but the antibiotics have been overused and bacteria in the animals have become resistant to the drugs.

Eventually these resistant bacteria have come into contact with humans. The FDA’s mandate would eliminate over-the-counter use for the main purpose of boosting growth in healthy animals. Antibiotics can only be used to treat or prevent disease and must be prescribed by a veterinarian.

LaPook told the “CBS This Morning: Saturday” co-hosts that more than two million Americans are affected by these resistant infections.

He said that the new regulations will be start off being voluntary and the FDA is doing that because “it’s just quicker.”

“They’re going to take another look in three years, and depending upon how many people are on board, they may have to reassess,” he said.

LaPook also said that the reaction was from the food industry is good and many of them seem to be on board.

“The major pork trade association said they’re on board, and two of the biggest suppliers of the antibiotics that go into the feed say they’re on board,” he said. “So we’ll see.”

Also, the city that banned transfats, required calorie counts on menus, and tried to limit the size of soft drinks made headlines again.  New York’s Board of Health voted on Wednesday to make flu shots mandatory for all children under the age of 5 in public schools and daycare facilities.

Phillips told the “CBS This Morning: Saturday” co-hosts that this is the “Department of Health responding to just incredible numbers.

“Forty percent of children in New York City between the age of 6 months and 5 years old get the flu every season, especially if they’re in this setting - nursery school, day care,” she said. “Four kids died last year in New York City, so they’re really reeling from these numbers. The push is to get more people vaccinated and to recognize that also kids are the first vector of flu in the community. They tend to get it earlier, and they get it in large numbers and pass it to the rest of the population.”

Phillips said that “vaccines are, of course, a sensitive topic” but the flu shot is "not the first vaccine that is required.”

“We are required to give our kids measles, mumps, tetanus and other things,” she said. “This is one that can make a really big difference in just a short amount of time.”

For Dr. Jon LaPook and Dr. Holly Phillips' full roundup on this week's medical stories, watch the video in the player above.

Check out more from Morning Rounds with Dr. LaPook