An antibiotic-resistant sinus infection like the one Edmonton Oilers owner Daryl Katz is fighting can slowly poison the entire body, says a microbiologist.

"Bacteria need to eat and when they're in your nose, there is really only one thing that they can eat and that is your cartilage and your cells," said Jason Tetro, an independent researcher in health-related microbiology and immunology, from Toronto.

"You may start off with a breakage in the septum, or it may create holes that are going to need reconstructive surgery.

"But more importantly, if it goes into your bloodstream, you're going to need antibiotics through an IV which is part of the reason why Katz has been seen with an IV bag."

News of Katz's ongoing health issues surfaced Tuesday following a rare public appearance by the reclusive billionaire.

A noticeable change in Katz's appearance at a news conference prompted wild speculation on social media.

Katz speaks during the ribbon-cutting ceremony at Rogers Place Arena on Sept. 8, 2016. (Jason Franson/The Canadian Press)

The Oilers Entertainment Group responded with a statement confirming that Katz has been dealing with a life-threatening sinus infection. He has reportedly undergone three surgeries in the past 10 months.

Even when treated, bacterial sinusitis can be deadly, Tetro said.

"It really comes down to one thing and that is antibiotic resistance," Tetro said in an interview Friday with CBC Radio's Edmonton AM.

Antibiotic-resistant infections are becoming more prevalent, he said. When they are resistant to multiple forms of antibiotics, the results can be dire.

People can spend years undergoing treatment and trying to find the right drug regimen to fight off stubborn bacteria.

"In some cases, as many as six out of 10 isolated strains are going to be antibiotic resistant," he said

When that happens, instead of a couple of weeks, you probably have months to years, to possibly even a lifetime fighting this from taking over your body."

Sportsnet hockey analyst John Shannon said he was told by the Oilers that Katz has been fighting the infection for years, including last time the Oilers were in the playoffs in the spring of 2017.

"[Katz] carried an IV bag 24/7 during the playoff run, 2 seasons ago. The infection has a 50-50 survival rate. He's had 3 surgeries over the past 10 months with 1 more surgery to go. It is the primary reason why he hasn't been around Edmonton and the team," tweeted Shannon.

"He is through the worst of it and the long-term prognosis is positive."

'Just like the flu'

Tetro said the infections are highly contagious and easily transmitted from person to person. He said good hand hygiene practices are the best way to guard against an infection.

"It's actually just like the flu," Tetro said. "It could be as easy as shaking hands with someone who has just sneezed. That's why people like myself are so adamant about hand-hygiene practices.

"I would rather make sure that my hands are clean than go to the doctor's office and find out that I have a long journey ahead trying to fight off a bacterium."