UTI Flashcards
What are the rates of infections in 65+ between men and women? Under 65?
The same rate in both genders
Under 65: females get it more
Where is urine sterile? Where is it not?
Sterile: kidney, bladder
Non-sterile: Urethra
What type of tests quantitative/qualititative of urine examination can yield meaningful results?
Quantitative
Define where Lower vs Upper UTI are from? What are they called?
Lower: cystitis (bladder, urethra)
Upper: pyelonephritis (kidney, renal pelvis)
Differentiate between ascending and descending (hematogenous blood-borne) route of infections?
Ascending route
- self-inoculation of the urethra with fecal bacteria
Descending route
- usually a result of bacteremia
- spread of bacteria from bloodstream to other organs
- not person to person
- movement of urine in body
What are risk Factors of UTI
- Diabetes
- Obstruction of urine flow (kidney stones, tumour)
- female
- Catheterization
- Previous antibiotic use
- Pregnancy
- Hospitalization
What are the 4 host defence mechanisms. Give examples of the first 2.
- inhibit bacterial growth:
- Low pH, prostatic secretions in male - Anti-adherence factors:
- Glycosaminoglycan (found on bladder), Tamm-Horsfall protein (uromodulin) - Lactobacillus in vaginal flora
- Estrogen level
What are potential microflora that are present in the distal portion of urethra (3)
- coagulase negative staph (Epidemidis, saprophyticus)
- lactobacilli (non-spore forming)
- diphtheroids
What are potential pathogens that can be transient colonizers in the urethra (2)
- enterobacteriaceae (gram-neg aerobic)
- occasional yeast
What bacteria accounts for uncomplicated UTI
E. coli
Which bacteria accounts for complicated UTI (3)
- Enterobacteriacae (klebsiella, proteus)
- Pseudomonas species
- some gram-positive bacteria
Which bacteria is common in UTI with sexually active women
Staph Saprophyticus
Which gram-positive bacteria is the most common pathogen in UTI
Enterococci
When can you isolate Candida Albicans (yeast) species from (3)
- Catheterized patients receiving antibacterial therapy
- Diabetic individuals
- Hospitalized patients
What are examples of virulence factors of E. coli (2)
Fimbriae (bacterial adhesion)
Hemolysin (a cytotoxic proteins that lyses cells)
Which is more severe? lower UTI, Upper UTI
Upper UTI
What are signs of symptoms of lower UTI?
- frequency of micturition
- dysuria
- suprapubic heaviness
- urgency
- Darker browner urine (gross hematuria)
What are signs and symptoms of Upper UTI?
- Pain and tenderness involving the flank
- Fever
- Nausea
- Chills
- malaise, headache
T/F Clinical symptoms correlate highly with PRESENCE or EXTENT of infection
False
Explain the condition acute urethral syndrome?
Who gets it?
Quantitative culture result #?
Most common symptom + lab findings?
Explain
- symptomatic abacteriuria (not caused by bacteria)
Who gets it?
- most common in sexually active women
Quantitative culture result #?
- less than 10^5 CFU/mL urine
Most common symptom?
- Pyuria (presence of WBC in urine)
- 8+ WBCs/mL of unspun urine OR
- 2-5 WBC/HPF of centrifuged urine
What do gram stain microscopic examination help with?
Differentiating between bacteria or yeast
What do pyuria microscopic examination test for? Lab values for diagnosis? Is it a definite diagnosis?
Examine urine for leukocytes
- 8+ WBC of unspun urine OR
- 2-5 WBC HPF of centrifuged urine
Pyuria can also be associated with other diseases
Explain leukocyte esterase test
- host response to infections in the prescence of PMNs (polymorphonuclear neutrohpils)
Explain Nitrate Reductase Test
Looks for presence of urinary nitrite, indicator of UTIs
- Pathogens reduce nitrate to NITRITE, looks for enzyme nitrate reductase
Which 2 tests if positive are strongly suggestive of a bacterial UTI
Positive leukocyte esterase & nitrate reductase test
What are reasons Nitrate tests may be negative? What strains?
- if the pathogen cannot reduce nitrates
ex. Staph saprophyticus and Enterococcus faecalis - or if the bacteria are few in the urine
What are limitations of screening methods for sensitivity (1) and specificity (2)
Sensitivity: not enough specimen
Specificity:
- cannot differentiate pyuria (bacterial) vs sterile pyuria (cannot culture, could be yeast)
- Some bacteria cannot reduce nitrate
How do we culture the urine? What are limitations of culturing the urine?
MacConkey agar
- 24+ hrs and 35 degrees anaerobically
Limitations
- not all bacteria can be cultured (eg. funghi)
What are diagnostic criteria for UTI (4)
1. Symptomatic patients
2. Symptomatic female
3. Asymptomatic patients
4. growth where?
- Symptomatic patients: 10^5+ CFU/mL
- Symptomatic FEMALE: 10^2+ CFU/mL
- Asymptomatic patients 10^5+ CFU/mL in 2 consecutive tests
- Any growth in the suprapubic aspiration (sticking needle in bladder) in a symptomatic patient
What examples of patients with UTI who can yield LESS THAN 10^5 CFU/mL (2)
- Patients who received antimicrobial agents
- Patients with urinary obstruction
Which condition is confused with UTI that has less than 10^5 CFU/mL as well?
Acute urethral syndrome
- do NOT have UTI
- symptoms not caused by bacteria
Explain sterile pyruria (abacterial pyuria)? What factors can cause this? (3)
UTI but no bacterial growth
Factors
- Chlamidya, trichonomas or virus
- Anaerobic bacteria (chlamydia)
- Kidney disease or autoimmune disease
Which treatments are used for UTI (3)? and complicated UTI (1 class)
Sulfamethoxazole, nitrofurantoin, cephalexin
Complicated UTI: fluoroquinolines (eg. cipro, levo)
