Preventing Antibiotic Resistance

Missed Antibiotic Doses Lead to Ineffective Drugs

Apr 13, 2006 Georgene A. Bramlage

When antibiotic prescriptions are not followed, drug resistant bacteria evolve and antibiotics become less effective. Proper use of antibiotics is essential.

Did you know viruses not only plague humanity in the form of the common cold, influenza, and exotic diseases like Ebola- viruses also infect bacteria? In fact those bacteria infecting you may also have a virus. Of course, Salmonella doesn’t get a runny nose and E. coli isn’t sneezing when infected by viruses known as bacteriophage.

Bacteriophage: Viruses Infecting Bacteria Contribute to Antibiotic Resistance

Bacteriophage take their toll by a reduction in reproductive fitness. Infected bacteria don’t multiply as rapidly and may have a more limited range of viability. Under most circumstances uninfected bacteria dominate the population. But bacteriophage can confer special traits such as increased virulence and antibiotic resistance. In fact, the E. coli 0157:H7 that you fear in undercooked hamburger is so deadly precisely because it is infected with its own virus.

At times, these virus-infested bacteria gain the upper hand in bacterial reproduction. Many forms of antibiotic resistance are borne on a form of bacterial viruses called plasmids. When you take an antibiotic prescription to fight off bacterial infection, the uninfected bacteria are eliminated and bacterial strains with even the slightest resistance increase in number.

Proper Use of Antibiotics is Critical to Avoid Resistance

Two factors become critical when using antibiotics. You must take your doses on time and complete the whole course. If you miss a dose, your blood levels of antibiotic fall below the MIC, or minimum inhibitory concentration, and drug resistant bacteria will reproduce. When you eventually take your next dose, the bacteria inhabiting your body will consist of a greater proportion of resistant strains and your medicine will be less effective.

What if you start feeling better and leave your antibiotic to gather dust in the medicine cabinet? Bacteria with greater antibiotic susceptibility are killed in the first few days of treatment, leaving those pesky resistant strains to be knocked out later in the course. There may be too few resistant bacteria present for you to feel sick, but with bacterial competition wiped out and lax adherence to your doctor’s orders, in a few days they will multiply and you will feel sick again. This time your infection will consist predominantly of resistant strains and the next treatment may fail. That person you just coughed on also has the added bonus of infection with a drug resistant strain.

Take your antibiotics on time and always finish your prescription. When you don’t, the drugs we use to fight bacterial infection become less effective as resistant bacteria selectively survive resulting in bacterial evolution.

Tips for Proper Antibiotic Use

Centers for Disease Control and Prevention guidelines:

• Ask your doctor if your outcome will improve from taking an antibiotic.
• Don't take antibiotics for viruses like the common cold or influenza. Antibiotics are only useful for bacterial infections.
• Take your antibiotic exactly as prescribed. Don't skip doses, finish the full course, and do not save or share medicine.
• If your doctor says your illness will not improve with antibiotics, do not pressure your provider for a prescription. Ask about other ways to relieve your symptoms.

The copyright of the article Preventing Antibiotic Resistance in General Medicine is owned by Georgene A. Bramlage. Permission to republish Preventing Antibiotic Resistance in print or online must be granted by the author in writing.