Avoiding Antibiotic Resistance Evolution
Missed Antibiotic Doses Lead to Ineffective Drugs
May 27, 2008
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.
If You Miss an Antibiotic Dose
When you miss a dose of antibiotics, the best course of action is to take a dose immediately and reset the clock on timing your doses. For example, if you normally take your dose at 6 AM and 6 PM and realize at 8 AM that you forgot a dose, take it immediately and then take your next dose 12 hours later at 8 PM.
If you don't remember a missed dose until it is almost time for your next antibiotic dose, it is generally not okay to take two doses as this increases side effects. When in doubt check your patient information leaflet, talk to your pharmacist, or call a nurse at your doctor's office for specific instructions.
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