Test Miss Bacteria That Cause Infections
- Culture tests are insensitive and miss many pathogens that cause infection it favours fast-growing bacteria, like e-coli, and is unable to culture slow-growing bacteria orpathogens that die on contact with oxygen. The culture test detects as little as 12% of other clinically significant species that can cause infections. 1
- The dipstick test only looks for the presence of gram-negative bacteria, as e-coli, ignoring other possible pathogens that cause infections.
- The dipstick detects the nitrites which are produced by gram-negative bacteria and white blood cells, produced when the body is fighting an infection. But even then the dipstick test misses infections Positive for nitrite in less than 18% of UTIs and positive for leucocytes in less than 40% of acute UTIs with a positive MSU culture. 2,3,4
- The dipstick and culture test do not detect bacteria that are dormant and embedded in the bladder wall, so they fail to detect embedded, chronic infections. Dipstick test fail to detect 40% of chronic infections. The MSU test fails to detect 90% of chronic infections. 2,3
Patients With Colovesical Fistula
Q18: Are patients with colovesical fistula excluded from meeting the NHSN UTI definition?
No. Patients with colovesical, enterovesical, or rectovesical fistulae are not excluded from meeting the NHSN UTI definition. NHSN surveillance for infection is aimed at identifying risk to the patient that is the result of device use in general, not aimed at a specific device. An indwelling urinary catheter in place puts the patient at risk and, therefore, is included in CAUTI surveillance.
The purpose of submitting a urine specimen for culture is to determine infection. The NHSN definitions currently account for contamination of urine specimens. NSHN excludes specimens with a culture results of more than two organisms for use in meeting UTI definitions.
Number Of Organisms In Cultures
Q6. I have a patient that had a positive urine culture with 100,000 CFU/ml of E. coli and then, within the repeat infection time frame , another urine culture that had greater than 100,000 CFU/ml of K. pneumoniae and E. faecium. Can I use these cultures to meet the UTI criteria or, because there are more than 3 organisms in the UTI RIT, would they be excluded?
Do not add multiple cultures together. More than 2 organisms in a single urine culture suggests the possibility of contamination of the specimen. The same is not true for separate urine cultures with less than 3 organisms in each.
In this example the first culture would be eligible for a UTI. If no UTI was associated with that urine culture, then the second urine culture could be considered for UTI, since no previous UTI RIT was set and there were not more than 2 organisms in that urine culture.
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What Happens During A Urine Culture
A urine culture requires a clean catch urine sample. This term means a urine sample as free of outside contaminants as possible, such as normal bacteria that live on your skin. You might provide this sample at your healthcare providers office or a lab testing facility. In certain situations, you might collect the urine sample at home.
Uti Symptoms: Urinary Urgency Urinary Frequency And Dysuria
Q10: If a patient has a history of urinary urgency, urinary frequency or dysuria can another recognized cause be determined?
No, with no other recognized cause does not apply to these symptoms. In the presence of a positive urine culture which may have been collected as a differential diagnosis for suspicion of UTI it would be very rare that there is another associated cause for urinary urgency, urinary frequency and dysuria which are hallmark UTI symptoms.
Q11: Can these symptoms be used on the same day when the indwelling urinary catheter was removed and reinserted?
Yes. IF these symptoms occurred when the indwelling urinary catheter was not in place at the time of the symptom, it can be used as an element even on a day when the indwelling urinary catheter was in place for part of the day.
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What This Means For Your Treatment
Probiotics are often used alongside antibiotic treatment. When it comes to overseeing your own microbiome treatment, Dr. Thomas-White notes that the probiotics commonly sold as supplements are safe to try.
However, depending on the quality and your own microbiome, they may not help.
If you are looking to apply an idea from a study to your own treatment, your personal results may not be the same as those described in the literature.
Because probiotics are live organisms and prone to mutation, they are practically impossible to regulate by the Food and Drug Administration . Therefore, as with many natural supplements, whats in the product may not match whats on the label.
Its important to look into the companies producing probiotics and other supplements to determine whether or not the product they provide is high quality.
While probiotics are an unregulated product, there are third-party companies that test supplements and other natural products and post their findings online.
Dr. Thomas-White recommends selecting a probiotic that is refrigerated, as only Clostridia and Bacillus organisms are shelf-stable.
What Uti Strip Test Indicators Mean
Studies show that UTI test strips may only be reliable about 30% of the time.
|My urine was visibly cloudy and it burned when I went to pee. My doctor used a UTI test strip in my urine sample and said everything on the test strip was normal. I was told I didnt have an infection even though Ive had UTIs before and I know exactly what they feel like.|
Some studies have bluntly concluded that UTI test strips should be abandoned as a tool for the diagnosis of UTIs in patients with lower urinary tract symptoms.
Given the low accuracy of UTI test strips, if the results are negative but you have UTI symptoms, it would generally be recommended that you have a urine culture test done in a lab.
Which brings us to the next problem
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How To Culture Urine
Bacteria will continue to multiply in the warm medium of freshly voided urine. It is therefore mandatory that urinalysis and culture tests should be performed without delay. The average time of replication of E. coli is n minutes, so that the number of bacteria increases exponentially with time . If bacterial examination is delayed by more than 2 h, specimens must be stored at 4°C, but for no more than 48 h. Dip-slide culture or a similar semiquantitative method of culture is generally preferable. These methods offer the advantage of reflecting the true approximate concentration of bacteria at the time the sample is taken so that storage at low temperature is unnecessary.
Occasionally, unusual or fastidious bacteria may induce UTI. These bacteria are difficult to detect without examination of the urine using Gram stain . For example, Haemophilus influenzae and Haemophilus parainfluenza do not grow well in culture media commonly used for enteric bacteria and as a result may go undetected. Other unusual organisms include Pneumococcus, Campylobacter, Legionella pneumophila, Salmonella, Shigella, Corynebacterium group D2, acid-fast bacilli , and fungi . Gram and acid-fast stains should be performed for patients with urinary symptoms and pyuria when routine cultures are reported to be negative.
The Science Behind Probiotics
Many people with chronic UTI do not feel they receive adequate information from their doctors. Therefore, they often do their own research.
In your own research, you may have come across in vitro and in vivo in the scientific literature. But what do these mean and what significance do they have to your treatment methods?
|Dr. Thomas-White explains that in vitro refers to what happens in a test tube. In comparison, in vivo is what happens in a live organism, such as a mouse.|
Dr. Thomas-White explains that in vitro refers to what happens in a test tube. In comparison, in vivo is what happens in a live organism, such as a mouse.
The difference is important because sometimes an experiment will produce one set of results in vitro and another set of results in vivo.
Similarly, an experiment may produce one set of results in a mouse and a different set of results in a human. Dr. Thomas-White describes how, when it comes to the microbiome, these differences can apply to human demographics as well.
Diet, antibiotic exposure, and living in an urban versus a rural area all impact a persons microbiome.
A microbiome is like an ecosystem. One small change produces a series of changes, like a domino effect.
Consequently, the same experiment performed on people in various parts of the world may lead to different results.
Ive Gained My Life Back: New Tests May Help Those With Persistent Urinary Tract Infections
In 2015, Jessica Price, a 29-year-old Air Force veteran in Illinois, started experiencing urinary tract infection symptoms, including an unrelenting urge to urinate and bladder pain. But standard dipstick testing, where a doctor dips a plastic stick into a urine sample to check it for signs of bacteria, kept coming back negative. Based on her symptoms and the negative tests, doctors told Price she had interstitial cystitis , an incurable syndrome of unknown cause and suggested several invasive procedures that only worsened her pain.
I was on more medications than I can remember, none of which helped and some which made the symptoms worse, she remembers. The urologists told me things such as, This is just like having blue or brown eyes you were destined to have it.
But when a nurse practitioner turned to a new type of test that used DNA analysis of her urine, she found bacteria she said was abnormal, and Price began two years of antibiotic treatments that after some time finally brought her relief.
Other Influences Of The Bladder Microbiome
When it comes to fungi, research has shown that 100% of women have had a fungus identified. Compared to only 50-75% of women demonstrating bacteria in the bladder, this is a surprising finding.
While these fungi appear to be harmless, we ultimately have no idea of their impact on the microbiome or immune system. We know we sound like a broken record, but more research is needed into how fungi may be shaping bladder health.
The bladder biome includes two types of viruses: one that infects the person and another that infects the bladder-dwelling bacteria.
Viruses that can infect bacteria are known as bacteriophages, or simply phages. Phages and bacteria evolved side by side, with bacteria mutating to better protect itself against phages
In turn, phages have mutated to better side-step the bacterias defenses.
Phage therapy is based on the principle that, since specific phages attack specific bacteria, introducing that phage into an infected microbiome will eradicate the problematic bacteria without harming the beneficial organisms the way antibiotics do.
However, the rate of mutation of both the bacteria and the phages is a major challenge to phage therapy.
We recently wrote an in-depth article about bacteriophages, including how they work and ways to access phage therapy. Wed love to hear your thoughts on the topic!
Furthermore, since Lactobacillus feeds on estrogen, there is a direct link between estrogen levels and bladder health.
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Alternative Uti Test Methods You Could Try
We cannot reiterate enough No evidence of infection is not the same thing as evidence of no infection.
Or, to put it in a less mind-bending phrase just because your UTI test comes back negative, it does not mean you do not have an infection, particularly if the test used was a standard urine culture .
There ARE other testing options available, ranging from a modified urine culture test, right up to high tech genetic sequencing methods like those described below.
In addition to the information included here, weve also covered these testing alternatives in a resource and diagnostic directory you can download and share with your doctor. You can download this resource through our page about how to talk to your doctor about chronic and recurrent UTI or by completing the form below.
Check out our expert video series to learn more about how standard urine cultures are misleading and can lead to an inaccurate diagnosis.
|Theres an old expression, if it looks like a duck, walks like a duck, and quacks like a duck. It’s gotta be a duck. And so to have somebody who has pain, urgency, frequency and burning, and yet they’re told they don’t have an infection because a urine culture was negative, who do you believe? Are you treating a lab result? Or are you treating a person?|
If you feel you have exhausted your current options and you are still experiencing symptoms that impact your life, it could be time to learn more about how to move forward.
How Negative Urine Cultures Can Be Misleading
As many people with recurrent UTI have likely suspected, there is a high rate of false negative urine cultures. But if the bladder is not sterile, then why are so many standard urine cultures negative?
Dr. Thomas-White explains that in the 1950s, Dr. Edward Kass, an epidemiologist, designed a test to determine which patients were at risk of a kidney infection during or after surgery.
He did this by placing a drop of urine in a specific environment and noting what grew in 24 hours.
While this test was successfully able to identify the risk of kidney infections in patients, it was only useful for growing E. coli bacteria. The test failed to accurately grow and identify other organisms.
If E. coli is not present in high enough levels, a patient may receive a negative urine culture, despite possibly having imbalances of other bacteria.
The reason E. coli is used as a model organism across the world since the 50s is because it grows just about anywhere. Its the microbial weed of the scientific community.
Unfortunately, this urine culture was introduced into other areas of healthcare and used as a test for all UTIs, despite the fact that it did not successfully detect other bacteria.
For people who have UTI symptoms but receive negative urine culture results, the test can only determine that they are negative for E. coli.
The test cannot confirm that they are negative for a UTI caused by other organisms.
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Why Its Important To Find The Right Practitioner
While you may be able to request UTI testing independently, the results have limited usefulness without a practitioner who can interpret the information and prescribe an appropriate treatment regimen.
Because the types of UTI testing covered above are not widely available, many practitioners may not be aware of them at all. Or they may be aware of them but have no experience using them, or may believe them to be unhelpful.
Always find a practitioner to work with before ordering testing. Weve covered recurrent UTI treatment approaches in a separate article, so dive in there for more insight.
|With Microbiome testing, you don’t often get one bacteria. Certainly, I have found the usual suspects like E. coli. Ive even detected some STIs, and anaerobes that cant be grown by culture. Sometimes, you get long lists of bacteria that we know very little about, and I’ll do extensive literature searches and sometimes barely come up with one or two papers. And so what I generally do in that situation is to try and figure out which are likely to be pathogenic, and treat those. This is a really different way of prescribing antibiotics compared to when I was trained.”|
Negative Urine Tests With Kidney Infection
I’m a 61 year old woman, generally healthy but have just recently had a kidney infection. This was my second, previous one 2 years ago. First infection came on totally out of the blue with no preceding UTI. This time did have a UTI and stupidly accepted 3 days of Trimethoprim! 3 weeks later after feeling nauseous and exhausted for days, started back pain but it was Friday night! Had to go to emergency doctor who refused to believe it was a kidney infection due to negative urine test Long story short, eventually after 2 days got Cefalexin and have very slowly recovered. Have seen urologist who is concerned by the fact that my urine tests show no infection although he says that from my symptoms I have progressed to septicaemia on both occasion. This has frightened me a lot! Anyone got any advice for me? Please.
0 likes, 8 replies
4 years ago
I’ve recently gone through something similar. It was either a bladder infection or kidney infection , ALL tests come back negative and guess what happened next…an ultrasound months later due to stabbing pain showed my kidney had shrunk significantly in size! I’m really mad about this. I was going to donate a kidney to my mom, as she is likely gonna need one. It’s very unfair. I tried hard to get help for the symptoms, and was diagnosed with IC. Which the bladder does show I have. But still…They said it was likely due to infection.
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