"We are continuing to see cases occurring among patients," Dr. Ian Plumb, an epidemiologist at the CDC's Enteric Diseases Epidemiology Branch and lead author of the report, said in an email to CNN.
"The antibiotic resistance pattern of this strain is alarming because primary oral antibiotics used to treat patients with this type of Salmonella infection may not work, "he said.
The salmonella infections were linked to beef obtained in the United States and soft cheese obtained in Mexico, suggesting that this strain could be present in cattle in both countries, the CDC found. Eighty-nine of people who contracted the infection had recently traveled to Mexico.
"To prevent infection, consumers should avoid eating soft cheese that could be made with unpasteurized milk, and when preparing beef they should use a thermometer to ensure appropriate cooking temperatures are reached: 1
strain did not respond to ciprofloxacin and had "decreased susceptibility" to azithromycin – two antibiotic drugs often prescribed to treat Salmonella infections.
Most patients with salmonella infections recover without antibiotics, but those with severe infections need antibiotic tics. Resistant infections may be more difficult to treat, and patients may be at increased risk for developing serious complications.
The CDC said that avoiding the unnecessary use of antibiotics in cattle, especially those that are important for the treatment of human infections, could help prevent the spread of this drug-resistant salmonella strain.