A multidrug-resistant strain of salmonella that has sickened hundreds has been linked to Mexican-style soft cheese and beef, the Centers for Disease Control and Prevention (CDC) said in a warning this week.
The strain — salmonella Newport — sickened 255 people in 32 states from June 2018 to March of this year. At least 60 people were hospitalized and two died, the CDC said in its Morbidity and Mortality Weekly Report published Thursday.
The illnesses were mostly linked to soft cheeses purchased in Mexico and beef in the U.S., officials said.
Roughly 43 percent of patients reported visiting Mexico prior to falling ill, officials said, adding a number of them also recalled eating soft cheese and beef prior to infection.
In fact, “among patients who traveled to Mexico with information on food consumption, 87 [percent] reported eating beef, and 63 [percent] reported eating soft cheese; among those, 79 [percent] recalled obtaining the cheese in Mexico,” the CDC said.
In particular, many of the patients reported eating queso fresco — a soft cheese typically made with raw, unpasteurized milk from cows or goats — before they were infected.
In this outbreak, “consumption of cheese and consumption of beef were both associated with illness, indicating that dairy cattle were a likely source of these infections,” the CDC said.
“The reported consumption of queso fresco, travel to various regions in Mexico, and detection of indistinguishable Newport strains in beef and cheese suggests that contamination of soft cheese resulted from carriage by cattle rather than poor hygiene during cheese production. Dairy cattle often are used as a source of ground beef and have been implicated in previous [multidrug-resistant] Newport outbreaks.”
Specific brands were not identified.
The strain — which is “emerging" because it was not detected prior to 2016, according to the CDC — is resistant to azithromycin and ciprofloxacin, two antibiotics commonly prescribed to patients with severe salmonella infections.
Symptoms of salmonella usually develop 12 to 72 hours after being exposed to the bacteria, with most people developing diarrhea, fever, and stomach cramps. The illness usually lasts four to seven days and most people recover without treatment.
"In some people, the illness may be so severe that the patient needs to be hospitalized," according to the CDC. "Salmonella infection may spread from the intestines to the bloodstream and then to other places in the body."
Federal health officials say that children younger than 5 years of age, pregnant women, adults 65 and older, and people with weakened immune systems are more likely to have a severe illness.
The CDC estimates salmonella causes about 1.2 million illnesses, 23,000 hospitalizations, and 450 deaths in the U.S. every year. Food is the source for about 1 million of those illnesses.
To prevent infection, especially in this case, the CDC warns that consumers should avoid eating soft cheese made with unpasteurized milk. Beef should also be cooked to the appropriate temperature. Per the CDC, “145°F for steaks and roasts followed by a 3-minute rest time, and 160°F for ground beef or hamburgers."
Additionally, “avoiding the unnecessary use of antibiotics in cattle” could also help prevent multidrug-resistant salmonella strains, the agency added.
Fox News' Travis Fedschun contributed to this report.