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47 Cards in this Set
- Front
- Back
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Ports of entry for UTI
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1. blood (Str. Salmonella, Brucella, etc.)
2. lymphatics (esp. enteric bacilli) by connection bet. intestine and UT 3. iatrogenic --> medical devices: cathers, cytoscopes, etc. 4. injuries, chirurgic interventions, accidents 5. secondary infections b/c of stasis: calculi, pregnancy, tumors |
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inflammation of urethra =
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urethritis
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inflammation of urinary bladder =
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cystitis
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inflammation of renal pelvis =
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pyelitis
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inflammation of renal parenchyma =
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pyelonephritis
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2 microorgnisms causing acute infections
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E. coli (80-85%)
Proteus (8-12%) |
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2 microorganisms causing chronic infections
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Klebsiella
Pseudomonas aeruginosa (mixed infections of these two) |
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most common microorganism in bladder infections
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E. coli
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most common microorganism in upper UT infection
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Proteus
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UTI microoganism response to antibiotics
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Most microorganisms in UTI are resistant to antibiotics
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tests of urine: macroscopic and microscopic
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macroscopic: quantity, pH, proteins
microscopic: erythrocytes, leukocytes, epithelial cells, casts |
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bacteriologic evaluation: qualitative & quantitative
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qualitative: Pellet (after centrifugation) who?
quantitative: general count. how many? |
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instruments for urine collection
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-SPA - suprapelvic aspiration
-catheter |
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conditions of urine collection
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-devices (SPA, catheter) must be sterile
-urine should be tested immediately or kept in refrigerator till then b/c microorganisms can multiply & change quantity |
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hematuria
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-RBCs in urine
-tell us that something is wrong, that at the glomeruli level filtration is not good and RBCs are coming out |
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dysuria
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-can't give urine
-happens w/tumor, enlarged prostate, etc. |
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pyuria
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-pus in urine
-see a lot of leukocytes |
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nephropathogenic E. coli
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not all E. coli cause UTI but some types more commonly cause UTI than others (mostly O Ag 4, 7, 75)
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pyelonephritis is associated w/ a particular structure...
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associated w/ a particular pilus which connects bacteria to the tissue & therefore are not washed out.
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problem w/ Proteus mirabilis & Proteus vulgaris
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-they possess urease which breaks down urea into ammonia --> pH increases. this results in:
1. produce stones of bicarbonate phosphate (b/c minerals remain dissolved at acidic pH) 2. inactivates C4 in kidney tissue which inactivates bactericidal effect. This plus stasis of the stones result in infection |
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antibiotic treatment: bacteriological & pharmacological factors
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-sensitivity of microorganisms to the antibiotic
-place of infection: tubule vs. tissue -pH |
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importance of place of infection in antibiotic treatment
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the tissue site vs. the tubuli site
-antibiotics remain longer in the tissue than in the tubule -tissue site --> antibiotics w/glomerular excretion -tubuli site --> antibiotics w/ tubular excretion |
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importance of pH in antibiotic treatment
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there are antibiotics which act better in high pH and some which act better in low pH. so along w/ antibiotic can give compounds that alter the pH so drug will work better
-ammonium chloride and methionine decrease pH -Na2CO3, acetazolaminde increase pH |
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effect of fluid intake on antibiotics treatment
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-get dilution of the antibiotics as through the kidney there is filtration of 180 L/day
-part of the treatment is drinking, but this dilutes the antibiotics |
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duration of treatment
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usually 12-24 days
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recurrentis (return infections)
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So there are some infections where -you treat it and it goes away and returns again
-It could be the same microorganism but this microorganism has changed its sensitivity. -Or it could be by a different microorganism- so it is a different episode. |
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sometimes there is no cure, why?
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-the causative organism is different from what was isolated (b/c urine was not sterile)
-the same microorganisms which became resistant -the antibiotics did not reach the microorganism; persisters, protoplasts; bacteria can form biofilms by quorum sensing. biofilm is produced in vivo by the bacterium. sensitive to antibiotic on plate, but resistant in vivo. |
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best type of antibiotics for UTI
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quinolones: b/c don't have many side effects and don't have to be given IV. of course there are some bacteria that are resistant
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use of polymyxin
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used only in research purposes b/c it disrupts our cell membrane along w/ that of bacterium.
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use of tetracycline
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-stopped giving it to pregnant women
-can go to heart tissue and bones -good for external use |
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True or False?:
most bacterial UTI are due to the normal intestinal flora |
True
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medical device that is the main source of UTI
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catheter
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acute UTI
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Acute meaning coming suddenly with back pain, urinating with short times or at least feeling like you have to urinate. And occasionally temperature, not always. Acute is usually treated and that is it. Acute infections are caused only by one bacteria, most cases is due to E. coli (80-85% of the cases) and less often Proteus.
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chronic UTI
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mild in terms of symptoms.
lasts for longer period of time. caused by mixed infection of Pseudomonas and Klebsiella. |
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mixed infection UTI
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The problem with mixed infection (as we will see later) is that each has another pattern of resistance or sensitivity. And it maybe that one is sensitive to x and second is sensitive to y and may not give treatment to both because they are antagonistic, we will see later. S. coagulase neative that cause urinary tract the name was changed from S. epidermidis to S. saprophyties
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bacterurea
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bacteria in the urine
> 100,000 /ml midstream |
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2 risk factors for renal damage in UTI
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-obstruction
-underlying renal disease |
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bacterial virulence factors that favor UTI
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-urease
-fimbriae (can adhere to uroepithelium) |
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host factors that favor UTI
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-calculi
-ureteric reflux (some urine doesn't always go all the way down, there is a reflux) -catheterization (bacteria can enter at the point of contact bet. urethra and catheter. catheterization can also cause erosion to urethral epithelium which is a UTI risk factor) -tumor -prostatic hypertrophy (enlarged prostate presses on the urethra, narrowing it, so urine does not go out the normal way) |
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2 mechanisms of urease in bacteria that favor UTI
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urease splits urea into ammonia which is basic. pH increases. results:
1. produces stones of bicarbonate phosphate (calculi) b/c acidic pH would typically dissolve them. calculi lead to stasis which causes infections. 2. inactivates C4 in kidney tissue which inactivates bactericidal effect |
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diagnosis
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lab tests are very important for diagnosis of UTI
(bacterurea (infection) is considered at 100,000 bacteria/ml (10^5 bact/ml) b/c urine collection is not sterile so there is a base level of bacteria always. patients are asked to clean genitalia and only to collect urine at midstream.) there are grey areas: patient may only have 10^4 bactera/ml but if they have symptoms, then it is UTI |
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True or False:
Most microorganisms causing UTI are resistant to antibiotics |
True.
b/c most of these microorganisms are from the enteron and if you take antibiotics per os only the resistant flora of the GI will survive |
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some synthetic agents used in treatng UTI
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nitrofurantoin - furadantin
manedelamine nalidixic acid |
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antibiotics used in treatment of UTI
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gentamycin, kanamycin, neomycin
ampicillin, carbpenicillin, cephalosporins, streptomycin, polymixin tetracyclins, chloramphenicol, erythromycin quinolones |
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main Proteus species causing UTI
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P. morganii
P. vulgaris P. mirabilis P. rettgeri |
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main Klebsiella species causing UTI
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K. pneumoniae
K. rhinoscleromatis K. ozaenae K. aerogenes |
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main enterococci causing UTI
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Strep. fecalis
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