The UTI Dilemma

The UTI Dilemma

Most of us know someone who has had frequency, urgency and burning when they urinate but when they go to the doctor, they are told they don’t have a UTI. Sometimes they get better, sometimes they just deal with it, and sometimes it progresses until they have a fever and are treated. Earlier in my career I personally looked someone in the eye, thought they had a UTI and told them that they didn’t. What is going on?

The urine culture is the gold standard (or is it?)

For years clinicians have used >100,000 colony forming units (CFU) on a standard agar-based culture as the gold standard for diagnosis. Agar based cultures have been around since the 19th century and haven’t changed much. The >100,000 CFU number came from literature looking at asymptomatic women over 60 years ago. Some studies have shown symptoms with a pathogen growing out at >1,000 CFU can be diagnostic. Two problems with this:

1) most physicians have been taught you need higher counts to mean significance

2) Most labs don’t differentiate bacteria in lower numbers.

Research has shown >50% of UTIs involve polymicrobial infection, standard culture fails to identify >80% of these. Standard cultures do not find fastidious organisms, fungi or viruses. In complex patients we need to look beyond the standard culture.

The urine should be sterile (or should it?)

Newer techniques that use polymerase chain reaction (PCR) and next gen sequencing (NGS) show that many healthy patients without any symptoms have a complex microbial community within their bladder. Not only is this normal but it may be protective against symptomatic infections. This urinary microbiome is actively being studied and is not well understood. It may be detrimental to treat any organism found on these more sensitive studies as we risk damaging healthy bacteria.

I was diagnosed with Interstitial Cystitis (do I really have that?)

Patients with symptoms of a UTI but with a negative culture are often given other diagnoses. The diagnosis of Interstitial Cystitis, pelvic floor dysfunction or food intolerances are often given to patients with symptoms of recurrent UTI but negative cultures. New technology using PCR and NGS will often find pathologic bacteria in these patients.

I was diagnosed with recurrent UTI and now my cultures are negative (but I still hurt)

Recurrent UTI (rUTI) is diagnosed when a patient has 2 UTI’s in 6 month or 3 in 12 months. Treatment for rUTI may include prophylactic antibiotic, post-coital antibiotic, vaginal estrogen, or self-diagnosis and treatment (working with your doctor). Sometimes after treatment the cultures will change. This can happen for a few reasons.

Recurrent or Chronic UTI – You are clearing the bladder but have a source for reinfection. This can be a kidney stone, a urethral diverticulum, or other anatomic abnormality.

Embedded UTI – When your bladder is infected it damages the lining, or urothelium. Occasionally when the body is trying to heal itself it will bury living bacteria under a new lining. This can grow and erupt into the bladder causing flares of UTI symptoms. Culture results will be variable.

Biofilm – Biofilms are collaborative collections of microorganisms that work together to stay alive. They can include bacteria, fungi and viral particles and are kept together by a matrix of extracellular polymeric substances (EPS). Think of this like the slime we used to play with mixed with millions of microorganisms. Biofilms can change how they behave and become resistant to antibiotics. It is very difficult to diagnose and eradicate biofilms from the bladder.

If you are caught in the merry-go-round of UTI symptoms it’s time to get the right diagnosis, treat what is going on and then prevent it from happening again.