Microbiology : UTI Flashcards
Who is more at risk for UTI: Young Man or Elderly Female ?
Elderly Female . Much more
Females > Males
Elderly > Young, Adults
Old Woman = A walking UTI machine.
Which is the more common way for bacteria to get into the kidney: Ascending UTI Infection or hematogenous spread ?
Ascending UTI (Urethra –> Bladder–> Ureters –> Kidney)
What doe most renal infections seeding from bacteremia produce ?
Abscess !
Infection is usually seen in the parenchyma
What are common causes of Ascending UTI’s ?
Sexual Intercourse (Staph Saprophyticus)
Fecal Incontinence
Urinary Catheters (Staph epidermidis)
Retrograde Urine flow
Which local factors would render a person more susceptible to UTI ?
Physiological obstruction Infrequent voiding Neurogenic or Neuropathic bladder Detrusor muscle instability Congenital abnormality Retrograde urine flow Catheter Instrumentation Trauma Malnutrition Diabetes Hyperosmolality IC Tolerance to pathogen (cross-reactivity of host)
What is vesicoureteral reflux ?
Urine from the bladder flows retrograde back into the ureters and causes a backup of in the kidney. This flow of urine can lead to seeding of bladder infection into the kidneys .
Another variant is urethravesicular flow (urine flows from urethra into the bladder )
How does hyperosmolarity predispose someone for UTIs ?
Inhibits PMN migration to damaged tissue
Describe the inherent anti-microbial (UTI protection) in humans
Antibacterial activity of urine :
low pH; high organic acids
high urea concentration
high urine osmolality
Low vaginal pH
Flushing mechanism of bladder
Peristaltic movement of ureters
Estrogen (young women)
Anti-adherence effect of uromucoid
Local secretion of immunoglobulins (IgA)
Antibacterial activity of prostate secretions of post-pubescent males
Long urethra in malesWhat do indwelling catheters form that lead to UTI susceptibility ?
A nidus.
Allows for bacterial colonization
What common disease state in older males may lead to UTI ?
Prostatic hyperplasia
What is the most important factor that allows for bacterial colonization in the urinary tract ?
ADHESION !
Adhesion determines the extent of bacterial colonization
What is adherence specificity >
The type of adhesion molecules determines where in the urinary tract a bacteria can colonize
p-Fimbrae and Pilli are bacterial constituents that allow for …
adhesion !
Mutant fimbrae –> decreased pathogenicty
Maternal ab’s protect against pFimbrae
Define K-antigens
capsular acidic polysaccharides that show resistance to bactericidal action of Ig and complement … mainly anti-phagocytic.
What is the most important adhesion molecule made by UTI causing E.coli ?
p-Fimbrae
Besides reflux, what allows for the ability to ascend in the GU system ?
Intrinsic motility of the organism
Where in the GU is Acute Cystitis often seen ?
Lower (bladder)
Typically a superficial infection
What demographic often gets Acute Cystitis ?
Young Women
Do individuals who get Acute Cystitis, often have physiologic or anatomical aberrations that lead to the infection ?
NOPE…
However, residual bladder urine is associated with it
What are common signs of acute cystitis ?
Frequent urination (urgency) Lower abdominal discomfort BURNING PAIN and Feeling of FULLNESS
May see hematuria but not always
Where is inflammation seen in Tuberointerstitial disease ?
Kidney parenchyma and renal pelvis.
What will be seen on the kidney in uberointerstitial disease ?
Small abscesses
What are common symptoms associated with uberointerstitial disease ?
Fever and back pain (may see renal dysfunction)
Describe the clinical onset of Acute Pyelonephritis
Abrupt onset
Chills, fever, headache, back pain
Tenderness over costovertebral angle
bladder irritation in Acute Pyelonephritis will lead to …
dysuria, frequency and urgency.
Proteus mirabilis invlovement in Acute pyelonephritis causes what to occur ?
Magnesium ammonium stones
What occurs to the renal pelvis in Chronic Pyelonephritis ?
Scarring and deformation of pelvis
Is chronic pyelonephritis a cause of renal failure ?
YES !
Loss of tubular function in Chronic Pyelonephritis leads to
Polyuria
Nocturia
Mild proteinuria
Acute Urethral Sndrome occurs in 50% of women who also show …
Dysuria and frequency
Acute urethral Syndrome usually always presents with …..
Acute Cystitis
What infections typically present like Acute Urethral Syndrome ?
Chlamydia and Herpes
What percentage of pregnancies result in an Upper RTI ?
33%
What events in pregnancy predispose women to UTI ?
Estrogen and progesterone induced dilation of uterus, bladder, pelvis
increased bladder capacity
decreased ureteral peristalsis
vesicoureteral reflux
Who typically gets Complicated UTI (Cystitis and Pyelonephritis ) ?
Pre-menstral girla
Post-menopausal women
HOWEVER, if a man gets a UTI its is most likely going to be COMPLICATED
What percentage of nosocomial infections are catheter related ?
35-40%
Most asymptomatic
Greater risk in women
What class of bacteria are most commonly seen in catheter associated bacteremia ?
Gram -‘s
CATHETER ASSOCIATED BACTERIMIA IS MOST COMMONLY ASSOCIATED WITH CATHETER USE !
List the most common causative agents of G - UTI
Enterobacters
E.coli
Proteus mirabilis
Morganell morganii
Kleb pneumo
Psedomonas aeruginosa
MycoplasmaWhat are the most common forms of G + bacteria associated with UTI ?
Staph. saprophyticu
Staph epidermidis
Less common: Staph aureus, Clostridium
What is the most common yeast associated with UTI
candida
What is the most common pathogen seen in UTI ?
E.coli (90% of acute bacterial cystitis)
80% community
30-50% nosocomial UTI’s
K Antigens associated with E.cloi ?
O1, O2, O4, O6, O7, O75
E.coli K groups associated with Children ?
11, 24, 36, 37
What type of Pilli do all serotypes of E.coli have ?
Type I
What does Type I pilli bind to in order to adhere ?
Mannose Receptors
Strains that causes cystitis have a higher affinity for what than fecal strains ?
uroepithelial cells
Describe the symptoms seen in HUS caused by EHEC
Acute Renal Failure
Microangiopic Hemolytic Anemia
Thrombocytopenia
HUS due to EHEC is seen in what age group predominantly ?
Children under 10 years of age
What foods often contain EHEC ?
Contaminated (undercooked) beef
Unpasteurized milk
Fruit juices
EHEC infection often presents with bloody diarrhea. What is the most common serotype of EHEC ? What will it not do on MacKonkey agar ?
O-157: H7
It will not ferment sorbitol !!
What is phase variation ?
Although a bacteria has the potential to produce many different fimbrae with affinity for different body cavities, it usually will not produce all of them at once making the infection very specific for a certain type of fimbrae.
E.coli is associated with which disease which causes entrapment of air within the kidney ?
Emphysematous pyelonephritis
Who is most at risk for emphysematous pyelonephritis ?
Diabetics (especially women)
What are the main treatment options for emphysematous pyelonephritis ?
Nephrectomy
Anti-bacterial
Is Proteus mirabilis more associated with community acquired UTI or nosocomial ?
Nosocomial
Proteus produces which kind of pilli ?
Type I
Why is proteus’ ability to change its surface composition important ?
Allows it to adapt to conditions that may need a different attachment protein
Escape from phagocytosis
What kind of motility does proteus have ?
SWARMING
Proteus is urease + or - ?
+ !
Salmonella can cause what condition, which is associated with sepsis ?
Bacteriuria (often seen in the elderly)
Klebsiella: Nosocomial or CA UTI ?
Nosocomial
Enterobacter:Nosocomial or CA UTI
Nosocomial
Pseudomonas: Nosocomial or CA UTI
Nosocomial
Psedomonas, like salmonella, is a cause of bacteriuria. Unrelated to this is the fact that it is Oxidase (+/-) ?
+ !
Mycoplasma genitalium can be found in the healthy male urethra but also may be associated with which two infective states ?
Pelvic Inflammatory Disease
Non-gonnococal urethritis
Ureaplasma urealyticum causes what complication in pregnancy ?
Chorioamniotis
Premature delivery
In addition :
frequently transmitted from mothers to their infants, causing
pneumonia,
persistent pulmonary hypertension,
chronic infection of the central nervous system and
bronchopulmonary dysplasia.
What are the lab diagnostics for S.aureus
G+
Catalase +
Coagulase +
Non-Motile
What deadly complication can be seen with S.aureus UTI ?
Bacteremia
Lab diagnostics for S. saprophyticus
Gram +
Catalase and Coagulase -
Who is most at risk for UTI due to S. saprophyticus
young sexually active women (Honeymoon Cystitis)
Does Staph. epidermis typically cause infection in healthy adults ?
Nope, it is opportunistic
Which pathogen(s) are commonly found in patients with diabetes ?
Clostridia
Yeasts: Candida Torulopsis glabrata
Clostria, yeast and e.coli can often cause which disease that results from a direct UTI or a fistula from the GI tract connecting to the UT ?
Empysematous cystitis
In addition to chemotherapy and radiation. Which three viruses are responsible for hemorrhagic cystitis ?
Adenovirus (Type 11, more selective for UT) Varicella Zonster BK polyoma (may also be indicated in bladder cancer)
What are the four most common bacterial causes of prostatitis ?
E.coli
Proteus
Klebsiella
Enterococcus
In urinary tuberculosis where will you see the first lesion in this infection ?
Kidney
May progress to gall bladder, prostate, seminal vesicles.
How is TB spread to the UT ?
hematogenous spread
In which patients do you often see Urinary TB
Older patients with latent TB
In schistasomiasis, the eggs lead to what kind of reaction ?
granulomatous
What other disease is associated with schistosomiasis ?
BLADDER CANCER
What is the best way to diagnose UTI ?
Urine sample !
Use a hemocytometer on uncentrifuged urine
You can also gram stain centrifuged urine
