Antibiotic-resistant "super bugs" have become a major threat to public health around the world, the United Nations says in a report released this week.

The U.N. World Health Organization report focuses on bacteria that have evolved to the point where current antibiotics no longer can combat them to treat the infections they're responsible for.

The report is not a warning for a future time, U.N. officials say, because the threat is here today and puts persons of any age living in any country in the world at risk.

The time to act is now, they say.

 "Without urgent, coordinated action by many stakeholders, the world is headed for a post-antibiotic era, in which common infections and minor injuries which have been treatable for decades can once again kill," said Keiji Fukuda, WHO Assistant Director-General for Health Security.

The United Nations' concern over the issue is shared by a number of world health entities.

The U.S. Centers for Disease Control and Prevention has predicted "potentially catastrophic consequences" that could prevail if bacteria continue to evade treatment, noting super bug infections are involved in the deaths of around 23,000 in the United States annually.

Elevated resistance rates have been found globally in common bacteria involved in infections of the bloodstream, wounds, and the urinary tract.

Drug-resistant strains of bacteria that cause pneumonia and tuberculosis have also been seen worldwide, the U.N. report noted.

Pneumonia bacteria that are increasingly resistant to penicillin are now showing up in more than 50 percent of pneumonia cases in some areas of the world, it said.

In some parts of the Americas, the reported noted, as many as nine out of 10 infections involving Staphylococcus aureus are proving resistant to the antibiotic methicillin, a situation garnering its own acronym, MRSA.

As more bacteria show signs of antibiotic resistance, it raises the specter of diseases spreading more quickly and a corresponding higher death rate, Fukuda said.

"Effective antibiotics have been one of the pillars allowing us to live longer, live healthier, and benefit from modern medicine," he said.

Changes are needed in the way in which antibiotics are produced, prescribed and used or more and more of them will become ineffective with disastrous implications for the future, he said.