Salmonella is getting stronger in Michigan and could be a model for what’s happening in other states, according to a new study by Michigan researchers, including those from East Lansing’s Michigan State University, that appears in Frontiers in Medicine.
The new research shows there is an uptick in antibiotic resistant strains to salmonella, resulting in longer hospital stays.
“If you get a salmonella infection that is resistant to antibiotics today, you are more likely to be hospitalized longer, and it will take you longer to recover,” says Shannon Manning, MSU Foundation professor in the Department of Microbiology and Molecular Genetics and senior author of the study. “We need better detection methods at the clinical level to identify resistant pathogens earlier so we can treat them with the right drugs the first time.”
A day or more of misdiagnosis or improper treatment allows symptoms to get worse and resistant bacteria to become stronger while only a subpopulation may be killed.
Salmonella is a diverse group of bacterial pathogens that cause foodborne infections. Infected patients often develop diarrhea, nausea, vomiting, and abdominal pain. Some infections are more severe and can be life-threatening.
Each salmonella strain reacts differently to the range of antibiotics available for prescription by doctors, making getting treatment right the first time important.
In Michigan, doctors are seeing more strains that are resistant to ampicillin, a common antibiotic prescribed to treat salmonella. Multidrug resistance, or resistance to more than three classes of antibiotics, has also increased in Michigan and could further complicate patient treatment plans.
“We’re still uncertain as to why this is happening. It could be that these antibiotics have been overprescribed in human and veterinary medicine and that possessing genes for resistance has allowed these bacteria to grow and thrive in the presence of antibiotics,” says Manning. “Each state has its own antibiotic-resistance issues. It’s important that the medical profession remains vigilant to ever-changing patterns of resistance in salmonella and other foodborne pathogens, rather than look for a blanket national solution.”
Historically, salmonella has affected young children and the elderly, but there has been a rise in adult cases, suggesting that the epidemiology of the infections has changed in Michigan.
Patients with the Typhimurium strain are more likely to have resistant infections, as were patients infected during the fall, winter, or spring months.
Enteritis strain infections tend to have a higher occurrence in rural areas. This may be attributed to rural residents’ exposure to farm animals or untreated sources of water.
“Our results show the importance of surveillance, monitoring resistance frequencies, and identifying risk factors specific to each state and region,” Manning says. “The trends that are revealed can lead to new prevention strategies.”
Other researchers involved are from Wayne State University, Sparrow Hospitals, and the Michigan Department of Health and Human Services.
The full report is available here.