Urinary Tract Infections Flashcards
What would you call the presence of bacteria in the urine? Does the presence of bacteria in urine imply an infection?
Bacteriuria. Bacteriuria does not always imply a UTI.
A patient presents with dysuria, urinary frequency and urgency and no other symptoms. What type of infection do you suspect?
Cystitis: bladder infection or urethritis
A febrile patient presents with flank pain, dysuria, nausea and chills. What type of infection do you suspect?
Pyelonephritis: inflammation of the kidney and/or renal pelvis
What characterizes a complicated UTI?
- structural or functional abnormality present in the urinary tract
- pregnant women, the elderly, men, children
- chronic symptoms
- co morbidity or immuno compromised
- upper urinary tract disease (pyelonephritis)
Describe how UTIs generally start and factors that may complicate or increase the risk of infection
Usually due to patients own intestinal flora ascending route of infection: the organisms enter the urinary tract in a retrograde fashion.
Complicating factors such as catheters, nephrostomy tubes, surgery, urinary stones.
Risk factors include: aging, in females: short urethra, intercourse, pregnancy, contraceptives that alter normal flora, males: anal intercourse, prostatic hypertrophy, urinary tract obstructions, impaired bladder innervation,
Describe the etiology of UTIs, what bacteria is the most common cause?
Most are monomicrobial. Enterobacteriaceae account for 90% of all UTIs and E coli is the most commonly isolated pathogen (70%)
What are the 4 virulence factors of uropathogenic E coli
- p fimbriae: adherence to uro epithelial cells
- hemolysins/colicin 5: resistance to complement
- k antigen
- type 1 fimbria: interbacterial binding and biofilm formation
What makes proteus, morganella and providencia uropathogenic?
They are urease producing organisms. Urease degrades urea into ammonia which increase the pH of the urinary tract. Increased pH leads to struvite stone formation which obstructs urine flow and provides a matrix for bacterial growth
A young, sexually active female presents with cystitis. A urine sample is taken and a gram positive, coagulase negative cocci growing in clusters is isolated. It is resistant to novobiocin. What is the identity of the bacteria?
Staphylococcus saphrophyticus
How must urinary tract samples be transported/submitted to the lab?
State method collection, time and date collected.
Must be refrigerated if older than 1-2 hours
Unless transported in a boric acid tube, any samples older than 24 hours or not refrigerated will be rejected
Should all patients with a suspected UTI be cultured?
No, a dipstick test is positive for gram negatives 90% of the time. You would culture during a recurrent infection, if the patient is pregnant or if the infection is complicated
If a patient has uncomplicated cystitis, what would your choice of drugs be?
Nitrofurantoin, fosfomycin, TMP/SMX
If a patient has pyelonephritis, what would your choice of antibiotics be?
Ciprofloxacin or a beta lactam and aminoglycoside
