View Full Version : Broth Culture
09-01-2003, 09:50 PM
I asked this question before, but I don't remember the answer. I'm getting older you know. When I have urine cultures done, the lab does not give any result before 3 days and will grow it longer if you want. Does that mean it's a broth culture or does a broth culture require something more?
09-02-2003, 12:29 AM
I could be misunderstanding, but my understanding is that the broth culture uses a different method of culturing.
09-02-2003, 05:18 AM
That's what I thought too but I have no idea how to explain it to the lab technician. I always assumed 'cause they were growing it a week that it was the same thing, but now I'm not so sure. So if someone knows for sure, please fill us in.
07-23-2004, 03:06 AM
what the bacteria are grown on - which labs call a "medium." In a regular culture, labs try to identify bacteria that grow out on an agar medium plate, which is a sort of jello for bacteria. There are lots of different types of "jello" to choose from - types with blood (called blood or "chocolate" agar) and some that have special things added in to help specific types of bacteria grow. However, some species that are fastidious, or "picky", aren't very good at breaking down the jello to get at the nutrients in plate agar. They grow better in medium without agar, which is a nutrient broth. That's the only difference.
In a related note, some bacteria won't grow on cell-free media at all. Chlamydia's one example that has to grow on a special cell culture. :dogrun:
07-23-2004, 05:27 AM
The reason most labs prefer to do the agar cultures is that the plates come prefilled with the agar medium, and they can just grab one, spread the urine on it, and wait three days for bacterial colonies to grow up. These colonies look like little dots on the surface of the jello -- actually, if you've ever seen actual jello get moldy and gross in a fridge, you pretty much know what the plates look like once the culture grows up ;)
Then, sometimes it's really easy to identify bacteria, as many species form colonies of specific shapes and colors. In addition, if grown on the "blood" agar, strep and other bacteria with hemolytic activity (blood-destroying activity) can be differentiated if there is a clear circle around the colony.
Anyway, the broth cultures are more of a pain for a lab -- you have to mix up the liquid media yourself, often, and most diagnostic labs don't stock it. Then, when the culture grows, the bacteria are in solution and you can't do the colony identifying tricks -- the bacteria have to be spun out of solution and ID'd by other means. SOOOOOO, it's more labor intensive and may require a special lab.
07-23-2004, 02:11 PM
I have learned some things from the descriptions of different culturing techniques. Agar is the mainstay of the labs and is easy and faster (cheaper). But broth can enable the slower more fastidious to grow. It is more time consuming and slower (expensive). I know of two labs near DC that will do broth culturing and patients can send the specimens on their own.
I am involved in a research project using broth culturing and the PCR. The PCR is a molecular machine that uses the DNA in the urine to find bacteria. Both these are more sensitive and find bacteria when agar testing does not. If a lab tells a patient there is "no growth" on agar and the patient has chronic symptoms there should be a more extensive test done. Most doctors are satisfied with agar (been used for 50 years so must be good even though patients continue to suffer). We hope our research will prove that there are more extensive tests than agar. We have developed the PCR test and the results will be available and published this fall.
Have you seen the Swiss study published in the Journal of Urology? http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15201781
They used doxycycline even though they did not culture a bacterial species and 70% got better. They say their results argue for a search for better microbiological testing. It already exists if the labs would just use it. It is not rocket science either.
01-09-2008, 01:45 AM
broth culture is usually a 5 day culture. its more accuarate than a reg culture
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.