Confirmed: Urine Is Not Sterile

15

The popular notion that urine is sterile is a myth, new research finds.

Yes, the myth that comes up every time someone pees in a pool (or drinking water reservoir) is actually false. In fact, bacteria do live in urine, Loyola University researchers reported this week at the general meeting of the American Society for Microbiology in Boston.

Some of the bacteria may even be linked to certain bladder conditions that have long been believed to be neuromuscular, not infectious, in origin.

"We need to reassess everything we think we know about urine," study researcher Evann Hilt, a graduate student at Loyola, told Live Science.

Not-so-sterile pee

For years, even doctors believed urine was sterile. The myth goes back 50 years, Hilt said, when a screening method for kidney infections was developed. It was a simple and easy test that was soon applied to bladder infections, too.

But the test involved culturing only a small amount of urine in open air, at a temperature of 95 degrees Fahrenheit (35 degrees Celsius) for 24 hours. Not all bacteria grow in those conditions.

Hilt and her colleagues suspected bacteria might be present in healthy urine because a previous Loyola study found bacterial DNA in healthy urine. But those results, published in April 2012 in the Journal of Clinical Microbiology, did not prove that the bacteria were living.

To get to the bottom of the mystery, the researchers cultured urine (collected via catheter) on various substrates and in different conditions, such as without oxygen or with more carbon dioxide. If the original test was like a single seed planted in sandy soil in full sun, this new version was like planting 100 seeds in a variety of soils and locations. The researchers also let the bacteria grow for 48 hours, not just 24.

Written By: Stephanie Pappas
continue to source article at livescience.com

15 COMMENTS

  1. Bacteria has been found in the urine of people attending a clinic. Some of it in people with bladder problems. So no actual evidence that the urine of healthy people contains bacteria. Snappy title though.

    • I work summers in a hospital medical lab as a Hematology Technician. I have always assumed that urine was sterile while in the bladder. Therefore, a specimen collected with a syringe directly from the bladder would be bacteria free (in a healthy patient).

      However, once voided, all sorts of shit is present. The urine passes through some potentially “bacteria infested” terrain on the way out of the urethra. Any lab tech will tell you that opening a day old urine specimen unleashes some awful odors — generated (I’ve always thought) by bacterial growth.

      Under the microscope urine can be a visual circus. It contains casts and blood cells and epithelial cells and lotsa times bacteria. WHile it is true that working in a hospital means that most of the samples are from sick folks, “man on the street” collection would (IMO) bear out that you are correct –

      In reply to #2 by mmurray:

      Bacteria has been found in the urine of people attending a clinic. Some of it in people with bladder problems. So no actual evidence that the urine of healthy people contains bacteria. Snappy title though.

      • I hated working with urine. You’re right about urine under the scope. a veritable cornucopia of nastiness. Even the cleanest specimens would have the occasional white and red cells, a hyaline cast here or there, epi cells as mentioned, trace bacteria, and even some talcum powder crystals for obvious reasons. And these were the clean specimens. The less clean ones would be full of organic landmines – all of the aforementioned cells in addition to plenty of other urinary/bladder goodies – and would resemble the bottom of a murky lake or river. Nothing about urine ever seemed sterile to me. Even urine from a suprapubic tap would contain something.

        Back in the day, even though blood always held a far greater likelihood of infection, I hated getting urine on my hands far more than blood. Yes, of course I was gloved up for the most part but there were always occasion for some spillage/leakage. Ugh.

        In reply to #5 by crookedshoes:

        I work summers in a hospital medical lab as a Hematology Technician. I have always assumed that urine was sterile while in the bladder. Therefore, a specimen collected with a syringe directly from the bladder would be bacteria free (in a healthy patient).

        However, once voided, all sorts of shit i…

        • I actually love working with blood. The lab where I work has stations we call benches and you learn your assigned bench when you see the schedule. I love the CBC station. I love chemistry. I do not like the Coagulation station (I feel i am the most likely to make a mistake and mistakes in coag can be deadly). Blood bank is also kinda scary. We have a bench called block 5 where the tech does all manual stuff. Microscopy (cell counts etc), sed rates, sperm counts, and verification of abnormal results from the CBC station.

          My point: Blood is cool and interesting to work with. Piss is not. However, my very very least favorite thing to work with is sputum.

          In reply to #7 by Steven007:

          I hated working with urine. You’re right about urine under the scope. a veritable cornucopia of nastiness. Even the cleanest specimens would have the occasional white and red cells, a hyaline cast here or there, epi cells as mentioned, trace bacteria, and even some talcum powder crystals for obvious…

          • My last hospital position was at a large teaching hospital, Tampa General. We had an independent ER Stat Lab that was “fun” to work in because we were a level 1 trauma center. This is where I worked for a while. Understandably it was either very busy or very slow but I got to work autonomously, which I enjoyed for a time. And I was part of the ER team which was more fun than the general lab and held more cachet, though I didn’t really care about that. When the new pneumatic tube system moved us upstairs that was the end of my dalliance in the ER. I worked midnight shift and to echo a point of yours, my rotation through Micro for setups was always the lowlight of my week. Sputum’s of every conceivable color, consistency, volume, you name it. I even think I saw the face of a few favorite deities in some of those horrific sputum’s.

            Blood is cool indeed. I was lucky enough to work with some skilled pathologist’s who really helped with peripheral smear (differential) readings. In our setup the tech would get first crack at the diff and would set aside perceived abnormal smears. A pathologist would then review to either confirm or change the presumptive analysis. It was always very satisfying to get a concurrence on a diff that had significant abnormalities, particularly with no known prior condition. A step further than this were bone marrow biopsies, which were daunting in their invasive nature and also exhilarating, again, if you got the right hematologist/oncologist to work with. The tech is very involved in this procedure as the physician generally hands off the syringe full of marrow to the tech who then quickly makes a series of slides which will later be specially stained. Anyway, reminiscing obviously. But to bring it all home, much better than urinalysis.

            In reply to #9 by crookedshoes:

            I actually love working with blood. The lab where I work has stations we call benches and you learn your assigned bench when you see the schedule. I love the CBC station. I love chemistry. I do not like the Coagulation station (I feel i am the most likely to make a mistake and mistakes in coag c…

          • In reply to #9 by crookedshoes:

            However, my very very least favorite thing to work with is sputum.

            Stool for parasite ova“… on a requisition accompanying a pint “ice cream” carton would have been my least favorite task. At least we had a laminar flow fume hood!

            Once when I was a med tech student a couple of my classmates and I submitted a sample of gravy from the hospital cafeteria for “Ova and Parasites”. The tech rejected it because “the patient has obviously had a barium enema”. We had a good laugh. The cafeteria manager did not find the story so amusing. :-D

            Steve [formerly MT(ASCP) ]

          • Ah, parasitology, how I loathe thee. We of course used to call it “parashit” for short. I’m in FL though so we have/had plenty of goodies here.

            In reply to #12 by Agrajag:

            In reply to #9 by crookedshoes:

            However, my very very least favorite thing to work with is sputum.

            “Stool for parasite ova”… on a requisition accompanying a pint “ice cream” carton would have been my least favorite task. At least we had a laminar flow fume hood!

            Once when I was a med tech stude…

          • I took a week long state training in O and P (here in Pa) to add to my certification. 8 hours a day searching through stool samples for critters and their spawn. The head of the lab had a 50 plus foot long tapeworm in a big pickle jar. Some poor woman passed the damn thing and thought she had crapped out her insides!

            Let’s just say that i had never imagined that there were so many shades of brown!

            Hey, I am gonna write a book “the many shades of brown”. It will rival 50 shades of grey. It may not out sell it, but at least I’ll know the grammar and sentence construction will be better!

            In reply to #12 by Agrajag:

            In reply to #9 by crookedshoes:

            However, my very very least favorite thing to work with is sputum.

            “Stool for parasite ova”… on a requisition accompanying a pint “ice cream” carton would have been my least favorite task. At least we had a laminar flow fume hood!

            Once when I was a med tech stude…

      • In reply to #5 by crookedshoes:

        I have not read the actual study so I can’t really say, but one would think serious scientists would be able to find ways to exclude the problems you mention. In fact, the article actually suggests they have put some thought into their study. We know quite well what kind of bacteria that cause infections. The bacteria they found apparently weren’t the usual ones that we know cause infections. They extracted the urine through a catheter. If conducted properly that is no different from extracting urine direct from the bladder with a syringe. There is of course always the risk of contamination or that the people they examined were in fact unhealthy to begin with. But, given that you have a large enough sample and use proper methods these risks are manageable. If they weren’t most medical studies would not be worth the paper they are written on (or the binary code they are made up of is perhaps a better analogy these days).

        • I do like the research. I do like the attitude of the research team regarding

          “We don’t know if they’re a consequence of overactive bladder or if they are a cause of overactive bladder,” Hilt said. “We still have to perform more studies.”

          Awesome statement.
          But, wouldn’t the fact that the bacteria is causing a syndrome mean that it is not normal flora in a healthy individual?

          I love that they are “thinking outside the box” as far as culturing the samples at different temperatures and subject to different environments. “Let’s learn something” is a great way to approach science.

          It is just a bit puzzling. Let’s say they find a bacteria in some percentage of folks’ urine. But, the bacteria (let’s call it Urinam improba)
          only grows at 22 degrees celsius and under anaerobic conditions. The environment where the urine is being made is NOT 22 degrees and NOT anaerobic. So, what have we got???

          If the environment necessary for U. improba’s growth is most certainly not the environment in the human body, exactly what is being demonstrated? I’d be interested to see if, for example U. improba sits dormant in a human and then comes out of dormancy upon the death of the human (with the lowered body temp and the onset of anaerobic conditions).

          It is good research; it has stimulated thought and new questions to be explored.

          In reply to #8 by Nunbeliever:

          In reply to #5 by crookedshoes:

          I have not read the actual study so I can’t really say, but one would think serious scientists would be able to find ways to exclude the problems you mention. In fact, the article actually suggests they have put some thought into their study. We know quite well what…

  2. Well, although I’m sure this study is important for health professionals I can’t really say it impacts my life very much. But, I guess it’s bad news for all the “urophagists” out there.

  3. It must be old news week on RDFRS. Anyway, of course urine is sterile…unless you have an active or latent infection. And then – poof – not sterile. To quote Clarence Darrow out of context, this fact would not beguile a fairly bright child of 5 years of age. As a former Laboratory Scientist I can attest that we would see plenty of urine that was very far from sterile.

    Anyway, to echo another poster the title suggests this confirmation goes against all conventional wisdom. I’m not sure how conventional wisdom ever strayed from the likelihood of a waste product not being sterile in the first place. It’s always seemed a strange presumption to me though I suppose seeing cloudy urine at the lab every day certainly helped.

  4. For people who drink this stuff as a therapy: Evolution created the kiddneys very clever over time. they decontaminate the body usually very good. It doesn’t make sense to put it back in on the top. (Dr. Eckart von Hischhausen m.D and comedian …)

Leave a Reply