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Bacterial infection vs. viral infection: What's the difference?
By Mayo Clinic staff
- With Mayo Clinic internist
James M. Steckelberg, M.D.
read biographyclose windowBiography of
James M. Steckelberg, M.D.
James Steckelberg, M.D.
Dr. James Steckelberg is chairman of the Division of Infectious Diseases at Mayo Clinic, a consultant and a professor of medicine at Mayo Medical School.
A native of Fremont, Neb., Dr. Steckelberg was a Rhodes Scholar and graduated from the Mayo Graduate School of Medicine as a resident in internal medicine and a fellow in infectious diseases, and is board certified in both. He is the former director of the Infectious Diseases Research Laboratory at Mayo Clinic.
Dr. Steckelberg belongs to numerous professional organizations. He is a founding member of the Musculoskeletal Infection Society of America and a fellow with the American College of Physicians and the Infectious Diseases Society of America. He has served on many Mayo Clinic committees and is a member of the Department of Medicine Leadership Committee and the executive committee of the Division of Infectious Diseases. He also served on the editorial boards of "Mayo Clinic Proceedings" and "Antimicrobial Agents & Chemotherapy" and has been an editorial reviewer for more than a dozen publications.
Dr. Steckelberg's research interests include experimental models of infection, epidemiology of infection, and antimicrobial resistance and therapy of bacterial infections.
Tests and diagnosis (1)
- Lumbar puncture: Why is it performed?
Prevention (1)
- E. coli: How can I tell if food is contaminated?
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Question
Bacterial infection vs. viral infection: What's the difference?
What's the difference between a bacterial infection and a viral infection?
Answer
from James M. Steckelberg, M.D.
Simply put, bacterial infections are caused by bacteria and viral infections are caused by viruses. Infections caused by bacteria include strep throat, tuberculosis and urinary tract infections. Diseases that result from viruses include chickenpox, AIDS and the common cold.
Bacteria are single-celled microorganisms that thrive in many different types of environments. Some varieties live in extremes of cold or heat, while others make their home in people's intestines, where they help digest food. Most bacteria cause no harm to people.
Viruses are even smaller than bacteria and require living hosts — such as people, plants or animals — to multiply. Otherwise, they can't survive. When a virus enters your body, it invades some of your cells and takes over the cell machinery, redirecting it to produce the virus.
Perhaps the most important distinction between bacteria and viruses is that antibiotic drugs usually kill bacteria, but they aren't effective against viruses. In some cases, it may be difficult to determine whether bacteria or a virus is causing your symptoms. Many ailments — such as pneumonia, meningitis and diarrhea — can be caused by either type of microbe.
Inappropriate use of antibiotics has helped create strains of bacterial disease that are resistant to treatment with different types of antibiotic medications.
Next questionLumbar puncture: Why is it performed?
- Understanding microbes in sickness and in health. National Institute of Allergy and Infectious Diseases. http://www3.niaid.nih.gov/topics/microbes/PDF/microbesbook.pdf. Accessed Aug. 12, 2009.
- Litin SC, et al. Mayo Clinic Family Health Book. 3rd ed. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2003:485.
