UTI microbiology Flashcards
bacteriauria
refers to the presence of bacteria in the urine
uncomplicated UTI symptoms
Pain during micturition (Dysuria)
Nocturia
Cloudy Urine/Foul smelling urine
Frequency/Urgency
Lower abdominal pain
Haematuria/Pyuria
Pyuria is a condition where there are high levels of white blood cells or pus in the urine. It can make urine appear cloudy or discolored
the two main criteria used in laboratory reporting or diagnosis or bacteriuria or infection in the urine
greater than 10^5 CFU/ml (colony-forming units per milliliter) is significant: This means that if there are 100,000 or more bacteria per milliliter of urine, this level of bacteria is generally considered sufficient to cause an infection. This threshold is used in asymptomatic and symptomatic patients to diagnose a UTI.
The rationale is that a higher number of bacteria is more likely to be causing a significant infection in the urinary tract.
greater than 10^4 CFU/ml with WBCs in urine can also be considered significant: This criterion recognizes that 10,000 CFU/ml of bacteria might not always be enough to diagnose an infection on its own, but when combined with the presence of white blood cells (WBCs) in the urine (a sign of inflammation or infection), it can be an indicator of a significant UTI.
White blood cells in the urine (known as pyuria) are a marker of the body’s immune response to infection. Even if there are fewer bacteria present (less than 100,000 CFU/ml), the presence of WBCs suggests that the body is fighting off an infection, and therefore, the bacterial presence is likely significant and warrants attention.
how are the mutistix SG test strips used to screen for UTIs
by testing for leukocyte esterase and nitrates in the urine.
When the leukocyte esterase test is positive, it indicates that there are white blood cells in the urine, which is a strong indication of a UTI. However, if the test is negative, it means that WBCs (and thus significant inflammation) are not present in the urine, reducing the likelihood of a UTI.
for the nitrate test, If nitrites are detected, it strongly suggests a bacterial infection, as only certain bacteria(E coli) can perform the conversion from nitrates to nitrites
If the test is negative, it suggests that there are no bacteria capable of reducing nitrates to nitrites in the urine, making a UTI less likely.
Leukocyte esterase is an enzyme produced by white blood cells (WBCs)
The nitrate reduction test detects whether bacteria that typically cause UTIs (e.g., E. coli) can reduce or convert nitrates (naturally present in urine) to nitrites.
if both tests in he mutltistix 10SG test strips are negative then sure can we be that the patient is UTI negative
93%
In other words, if these two tests carried out in the multistix strips are negative , the probability of a UTI being present is low.
does not completely rule out UTI but lowers its likelihood
