1. Why do I have to take antibiotics for so long if I feel better already?
It is important to eliminate all of the bacteria that are causing your infection. For some infections, several weeks of treatment are necessary. This is especially important if you have endocarditis, which requires weeks of antibiotic therapy to cure.
The bacteria or fungi must grow to sufficient numbers in the nutrient media before they can be detected and identified. Usually this happens within a couple of days, but in some cases and with some microorganisms, it can take longer. Furthermore, some microorganisms are present in the blood in very small numbers. They must have sufficient time to reproduce and grow to quantities that can be detected.
3. Why did my doctor order more blood cultures after the initial cultures were drawn?
Additional blood cultures may be drawn to determine if bacteria present in the culture are persistent in the bloodstream (true pathogens). If they are not present in follow-up cultures, then bacteria from the skin may have contaminated the initial cultures. Additional blood cultures may also be drawn if you continue to have signs of sepsis but no microorganism is recovered from the first cultures collected.
This article was last reviewed on October 24, 2013. | This article was last modified on February 24, 2015.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
The modified date indicates that one or more changes were made to the article. Such changes may or may not result from a full review of the article, so the two dates may not always agree.