Bacteria develop coping mechanisms, and they block the antibiotic from getting inside or they produce enzymes that deactivate it, Parker says.
The bacteria mutate only when exposed to antibiotics, he says.
A person doesn't build resistance to antibiotics; the resistance occurs in the bacteria the person acquires, says Dr. Dino Delaportas, an infectious disease specialist with a practice in Hagerstown.
Patients sometimes insist on getting an antibiotic, and doctors have to persuade them that they don't need one, Delaportas says.
Antibiotics don't work against viruses and are not effective against the flu or the common cold, says Evans Prieston, assistant director of clinical services in the pharmacy at The Chambersburg Hospital in Chambersburg, Pa.
Antibiotics are used to treat serious bacterial infections, including pneumonia, kidney or bladder infections, infections of the brain and brain lining, meningitis and blood poisoning.
The bacteria streptococcus pneumoniae, which causes pneumonia, middle ear infections and meningitis, is a major concern because it is becoming increasingly resistant to antibiotics, says Dr. Diane Dwyer, director of the Epidemiology and Disease Control Program at Maryland Department of Health and Mental Hygiene.
The department is working with Johns Hopkins University, University of Maryland and Centers for Disease Control and Prevention on a campaign stressing the importance of using antibiotics safely.
Details of the program, which will target the Baltimore metro area, were announced Friday. Materials will be shared with local health departments in Maryland, Dwyer says.
"It's time to draw attention to the problem," Dwyer says.
The message isn't that antibiotics are bad; it's that their use needs to be limited, Dwyer says.
"Clearly antibiotics are a major lifesaver, and they have much improved life expectancy and quality of life when used safely," Dwyer says.
Overuse of antibiotics can lead to resistant strains of bacteria that are more difficult and more costly to treat.
Once a pool of bacteria has learned how to become resistant, it can pass genetic information along to other bacteria.
The resistance problem has been occurring since antibiotics were developed in the 1930s.
People in nursing homes and children in day-care centers are more prone to picking up resistant bacteria, Delaportas says.
Because of problems with resistance, new antibiotics constantly are being developed.
There are several hundred antibiotics available, and 50 to 100 commonly are used, Delaportas says.
The widespread availability also contributes to the resistance problem.
Antibiotics only can be obtained by prescription in the United States, but they can be purchased over-the-counter in many overseas countries.
Antibiotics can have side effects, including skin rash, upset stomach and diarrhea.
Recovery doesn't depend on the antibiotic alone, and you have take care of yourself by eating well and exercising, Delaportas says.
Tips for taking your medication
If an antibiotic is prescribed for you, it's important to follow the physician's instructions. Here are some tips for taking antibiotics safely:
- Take the proper number of doses per day, and never skip a dose. Follow the directions until a prescription is finished. If you don't complete a course of therapy, you risk developing resistant organisms.
- All antibiotics don't work the same.
- Always read the directions on the label. Some antibiotics are better absorbed into the bloodstream with food, while others work better on an empty stomach.
- Never take an antibiotic prescribed for someone else. You might be allergic or develop an adverse reaction.
- Ask your pharmacist about your prescriptions if you have any questions.