A strain of Salmonella Newport in some beef in the United States and in some soft cheeses in Mexico has been found to be resistant to antibiotic treatment, according to a release from the Centers for Disease Control and Prevention published Friday.
The CDC reported the results of a study conducted on Salmonella Newport that was not responding to two oral agents that are frequently recommended to treat Salmonella infections.
Resistance to antibiotics is rare in human cases of Salmonella, though most Salmonella patients don't actually need antibiotics at all.
For those who do, doctors are concerned that commonly recommended treatments won't be effective in the future if there are more antibiotic-resistant strains, Ian Plumb, an epidemiologist in CDC’s Enteric Disease Epidemiology Branch, and an author on the study, told USA TODAY.
"Salmonella Newport is one of the most common types of Salmonella, which is a major cause of foodborne illness in the United States," said Plumb.
This particular, antibiotic-resistant strain wasn't detected until 2016, said Plumb. It has since been detected on multiple occasions in cecal and beef samples along with a mix of queso fresco and Oaxaca cheese in the United States and Mexico.
Last year, there were 255 cases in the United States spread across 32 states, between March 2018 and June 2019.
The CDC, Plumb said, is monitoring any new cases of infection.
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"For patients infected with this strain of Salmonella Newport and who need antibiotic treatment, alternative drugs may need to be considered," said Plumb.
Plumb said that the CDC is concerned that the strain appears to be newly emerging. That means there could be more antibiotic-resistant infections in the future.
The CDC isn't alone in their worries.
Greg Frank, director of Working to Fight AMR, a group that fights drug resistant infections, told USA TODAY the report underscores the importance of antibiotic-resistant infections as a problem.
"Drug-resistant superbugs are now evolving much faster than we are inventing new antibiotics and other treatments to fight back against them," said Frank.
This strain in question, found only in beef and soft cheese, was linked to dairy cows. That's also worrisome, Plumb said, since the findings suggest that the strain could be spread in cattle.
"We know that any use of antibiotics, in people, animals, and the environment, can lead to the development and spread of resistant bacteria," said Plumb.
In the last few years, he said, there has been increased awareness about antibiotic-resistant bacteria, which can limit treatment options, said Plumb. So, when this happens, it can be a reminder to consider antibiotics a "precious resource" that should only be used in humans and animals when necessary.
To avoid Salmonella infection when eating beef or cheese, Plumb has a few tips:
Cook beef at a safe temperature. Ground beef should be cooked to at least 160°F and steaks and roasts should be cooked to at least 145°F.
Avoid eating soft cheese made with raw (unpasteurized) milk. A label can help you tell when a cheese is “made with pasteurized milk.”
Follow Morgan Hines on Twitter: @MorganEmHines.
This article originally appeared on USA TODAY: Antibiotic-resistant Salmonella strain found by CDC worries scientists