There’s an arms race between microorganisms that cause disease and our efforts to fight them with antibiotics.
Antibiotics are supposed to kill off the bad bugs, and they do. But sometimes a few have protective factors that enable them to survive. They live on, multiply, and often result in strains of bacteria that are resistant to the particular antibiotic meant to kill them.
This antibiotic resistance is spreading rapidly. Through natural selection, the pathogens that resist antibiotics flourish. “This is a war we will never win,” explains Michael Sadowsky, head of the University of Minnesota’s BioTechnology Institute. “The selection pressure is on microorganisms to survive. They want to live just as much as we do.”
Antibiotic resistance is a global phenomenon. It kills, hampers control of infectious diseases, increases the cost of health care, damages the economy, and threatens to send us back to a pre-antibiotic era. The list of antibiotic-resistant microbes and the diseases they cause read like the cast of a comic book:
- MRSA. This stands for methicillin-resistant Staphylococcus aureus. MRSA describes a number of strains of the bacteria that are resistant to several antibiotics, including methicillin. These bacteria can cause boils, abscesses, impetigo, septic wounds, heart-valve problems and toxic shock syndrome.
- Flesh-eating bacteria. While not all flesh-eating bacteria are antibiotic resistant, some are, and can cause necrotizing fasciitis, the fast progressing, sudden onset disease which leads to the rapid destruction of skin and muscle tissue. This disease can be caused by a variety of bacteria, including Group A streptococcus (Streptococcus pyogenes) and some MRSA strains of Staphylococcus aureus .
- Drug-resistant tuberculosis. In 2011, there were 630,000 cases of drug-resistant TB, or about five percent of the total cases.
- Antimalarial resistance. Resistance to sulfadoxine-pyrimethamine is widespread in most malaria-endemic countries.
U of M scientists rise to the challenge
Fortunately, there are some genuine super-heroes fighting the bad guys. A number of these heroes are at the University of Minnesota. In fact, enter the term “antibiotic resistance” in the Experts@Minnesota search engine and you’ll uncover more than 200 links. Here are just a few of the ongoing projects.
Randall Singer, D.V.M, M.P.V.M., Ph.D. Singer, associate professor of epidemiology, Department of Veterinary and Biomedical Sciences, has worked for over 15 years to understand the factors that affect the emergence, spread and persistence of antibiotic resistant bacteria in animal and human populations as well as in the environment. He uses molecular microbiology, mathematical biology, risk assessment and epidemiology methods to design strategies that reduce the risks associated with antibiotic resistance. He is currently working with the FDA and USDA to redesign the on-farm component of the National Antimicrobial Resistance Monitoring System (NARMS). Learn more
Linda Kinkel, Ph.D. Kinkel, professor, Department of Plant Pathology, has been researching the ecology of plant-associated microorganisms, especially antibiotic-producing bacteria, in native prairie and in agricultural soils. She is working to understand why soil microbes (Streptomyces) vary so much in their capacities to resist different antibiotics, and why certain soil bacteria maintain their antibiotic resistance even when antibiotics are not present. Her work will help to reduce the prevalence of resistance to medically important antibiotics in the environment. Learn more
Tim Johnson, Ph.D. Johnson, associate professor in microbiology, Department of Veterinary and Biomedical Sciences, is seeking to circumvent the spread of antibiotic-resistant bacteria in animal agriculture and healthcare settings. He focuses on mobile elements called plasmids that enable bacteria such as E. coli and Salmonella to become resistant to multiple antibiotics used to treat human and animal infections. These plasmids are responsible for the recent emergence of “CRE superbugs,” which are resistant to all antibiotic options in humans and represent a global threat to human health. Learn more
Satish Gupta, Ph.D. Gupta, Raymond Allmaras Professor of Emerging Issues in Soil and Water, Department of Soil, Water, and Climate, has collaborated with others to evaluate how antibiotic feeding in livestock affects the emergence and spread of antimicrobial resistance in the environment. Gupta’s group has evaluated the appearance of resistant microbes in manure, soil and dog fecal samples on farms using antibiotics. Their research has shown that antibiotic resistance is higher in manure from antibiotic-using farms. They have also examined the potential spread of antibiotics in land-applied manure through soil leaching and runoff as well as their uptake by vegetable plants. They have also explored to what extent manure composting can degrade different antibiotics. Learn more
Timothy LaPara, Ph.D. LaPara, associate professor of civil engineering, has been researching ways in which the spread of antibiotic resistant bacteria could be reduced by inexpensively changing our sewage sludge treatment processes. He has found that using methane generated by sewage-digesting microbes to heat the sludge to 130 degrees can effectively destroy the resistant bacteria that concentrate in sewage. Learn more
Michael Sadowsky, Ph.D. and Alexander Khoruts, M.D. Sadowsky, director of the university’s BioTechnology Institute, and Khoruts, associate professor of medicine, have collaborated to develop a novel treatment for Clostridium difficile infections, or C. diff, which kill 14,000 to 30,000 people annually and affect 340,000 people a year. While C. diff itself is not antibiotic resistant, its ability to take over the GI tract is caused by antibiotic use. The process they have developed to treat C. diff was recently licensed and planning for clinical trials is underway. Learn more
Post by Vincent Hyman, a freelance writer based in St. Paul, Minn.