UTI

Question 1

Host Defenses of the Urinary Tract

Answer 1

1) pH below 5.5
2) Chemical content (HIGH UREA)
3) Flushing mechanisms of urine

Question 2

Lower UTI Diseases

Answer 2

Cystitis, Urethritis, and Prostatitis

Question 3

Upper UTI/Ascending UTI

Answer 3

Nephritis and Pyelonephritis

Question 4

Urethritis and Cystitis Symptoms

Answer 4

Dysuria, Frequency, Urgency, Hematuria, Positive urine culture, NO DISCHARGE

Question 5

Prostatitis Symptoms

Answer 5

Lower back pain and perirectal area and testicular pain

Positive urine culture

Question 6

Pyelonephritis

Answer 6

FLANK PAIN, frequency, urgency, dysuria

Positive urine culture

May cause premature birth in pregnant women (20 to 50%)

Question 7

UTI (Diagnosis)

Answer 7

Urine Sample showing:

Positive Leukocyte Esterase (PYURIA = pus)
Positive Nitrite  (E. coli reduce nitrate to nitrite

Question 8

UTI (Community- vs. Hospital-Acquired)

Answer 8

Community: largely due to FECAL flora
-E. coli and Staph saprophyticus (Coagulase NEGATIVE)

Hospital: most often due to CATHETERIZATION
-Klebsiella, Enterobacter, Serratia, Pseudomonas aerugenosa, Enterococcus

Question 9

Enterobacteriaceae Family

Answer 9

Gram-negative rods
Normal INTESTINAL FLORA
Ferment glucose, reduce nitrate, catalase POSITIVE, oxidase NEGATIVE

Serology due to LPS: O antigen, K (capsular) antigen, and H (flagellar) antigen

Question 10

E. Coli (Characteristics)

Answer 10

Normal flora of colon
Virulence due to acquisition of PLASMIDS, INTEGRATED PROPHAGES, and PATHOGENICITY ISLANDS
Fimbriae or Pili
Ferment LACTOSE (unlike Salmonella or Shigella)

Causes –> Gastroenteritis, UTI, Sepsis, Nenonatal meningitis

Question 11

E. Coli (Virulence Factors)

Answer 11

1) Adhesins: bind to cells lining bladder and upper urinary tract (e.g. Type 1 Pili –> P PILI (UPEC) bind to sugar on uroepithelial cells)
2) Hemolysin: lyses erythrocytes and other cell types leading to induction of an inflammatory response
3) Endotoxin: inflammation

Question 12

Staphylococci (Characteristics)

Answer 12

Gram Positive, Facultatie anaerobe, form grape-like CLUSTERS

Catalase POSITIVE (unlike Strep)

Non-flagellate, non-motile, non-spore forming

Question 13

Staphylococci (Coagulase Testing)

Answer 13

Positive = S. aureus

Negative = S. epidermidis and S. saprophyticus

Question 14

Coagulase Negative Staphylococci (CoNS) (Characteristics)

Answer 14

Form BIOFILMS
Significant cause of community acquired UTI

Most common are:
1) S. epidermidis –> infections of IMPLANTED DEVICES/PROSTHETICS, BACTEREMIA, BIOFILM

2) S. saprophyticus –> UTIs
* Novobiocin RESISTANT* (unlike other CoNS)

Question 15

Proteus mirabilis

Answer 15

HOSPITAL ACQUIRED UTI
Gram negative enteric
20-45% of UTIs in chronically catheterized patients is caused by this

UREASE (alkalization of urine due to urea –> ammonia)
KIDNEY STONES
BIOFILMS

Question 16

Pseudomonas aeruginosa

Answer 16

***HOSPITAL ACQUIRED UTI***
Gram negative, aerobic, motile rod
***OXIDASE POSITIVE***
Non-fermenter
***Minimalist*** (Wide temperature range w/ minimal nutrition)
Opportunistic pathogen
Water-soluble pigments ***Pyocanin***
Hot tubs, sinks, hospitals
***Long-term indwelling catheters, obstruction in the GU system, urinary tract instrumentation or surgery***

Question 17

Enterococcus (Characteristics)

Answer 17

Gram positive cocci
Catalase NEGATIVE
Group D carbohydrate
Common endogenous flora of GI tract
***Tolerates HIGH salt and NOT sensitive to optochin*** (differentiates it from Streptococcus pneumoniae)

Question 18

Asymptomatic Bacteriuria

Answer 18

Older men and women (25-50%) NORMAL

Treatment (ONLY in 3 situations): 1) Pregnant women, 2) Prior Urologic surgery, 3) After renal transplantation

Question 19

UTI Treatment

Answer 19

Cystitis: Trimethoprim/Sulfamethoxazole

Pyelonephritis: AGGRESSIVE treatment with Fluoroquinolones (for Gram negatives), Amoxicillin (for Gram positives)

Asymptomatic Bacteriuria: NONE or Amoxicillin, Cephalexin or Nitrofurantoin