Urinary Tract Infections, UPEC, and P. mirabilis Flashcards
Why are urinary tract infections more common in healthy adult women compared to healthy adult males?
The male urethra is longer, so bacteria have to travel farther to infect
Why does age affect the occurrence of urinary tract infections in men?
At infancy, the immune system isn’t fully developed yet.
At older age, the prostate is less active and the bladder doesn’t empty as much, which causes for an increase in prevalence
What is an uncomplicated urinary tract infection?
Disease is limited to the lower urinary tract
No physiological/anatomical abnormalities of the tract
No recent hospital admissions
What is a complicated urinary tract infection?
Disease has most likely spread to the kidneys
Some structural abnormality in urinary tract
Recently admitted to the hospital
What is cystitis?
Inflammation of the bladder
What is pyelonephritis?
Kidney inflammation associated with P fimbrae
What is the most common bacterial pathogen(s) that cause uncomplicated UTI?
Uropathogenic E. coli (UPEC)
What is the most common bacterial pathogen(s) that cause complicated UTI?
Uropathogenic E. coli (UPEC)
Proteum mirabilis
What are the natural barrier defenses found in the urinary tract?
Complete voidance of bladder Urovesicle valves Mucous layer Normal microbiota pH
How does the UPEC adhere to urinary tract tissue?
Through fimbrae
Which UPEC adhesin is associated with cystitis?
Fimbral antigen FimH
Which UPEC adhesin is associated with pyelonephritis?
P fimbrae
Why are aerobactin and hemolysin important?
They are produced by UPEC.
Aerobactin prevents host cells from getting iron
Hemolysin has the ability to lyse host cells
Virulence factors of Proteus mirabilis
Flagella
Hemolysin
IgA protease
Urease
Whys is flagella important for P mirabilis virulence?
Allows for motility and chemotaxis
Why is hemolysin important for P mirabilis virulence?
Can destroy blood cells
Why is IgA protease important for P mitabilis virulence?
IgA is an antibody on the surface of host cells. IgA protease breaks down those antibodies.
Why is urease important for P mirabilis virulence?
It raises the pH of urine, making it easier for P mirabilis to survive, and cause further damage
Why is the production of urease dangerous in the urinary system?
It neutralizes the pH of urine (or makes it slightly alkaline) creating an environment that is beneficial for P mirabilis, and toxic for renal cells. It also enhances the formation of struvite urinary stones, which can lead to a chronic infeciton
How are UTIs diagnosed?
It is difficult because there is always bacteria in the urine, but it is hard to tell where they’re coming from.
Count the bacteria in the urine. Healthy bacteria >10^5 CFU/mL
Individual with dysuria >10^2 CFU/mL
When would antibiotics be prescribed in a healthy (or asymptomatic) individual for P. mirabilis?
If a woman was pregnant. We don’t want her to pass P mirabilis to the baby.
When would antibiotics be prescribed in a symptomatic patient?
3 day TMP/SMX therapy for acute cystitis
10-14 day therapy for someone with polynephritis
How can P. mirabilis be diagnosed?
Consistently alkaline urine
Or, the production of urease is a good indication
