Lecture 29

Question 1

main etiology of ascending and descending UTI

Answer 1

Enterobacteriaceae (E. coli)

Question 2

uncomplicated UTI

Answer 2

– Infection involving structurally and functionally normal urinary tract.
– Healthy, young, non-pregnant women
– ~95% monomicrobial (E. coli)

Question 3

complicated UTI

Answer 3

– Infection involving structurally and functionally abnormal urinary tract.
– Predisposing anatomic, functional, or metabolic abnormalities, catheter.
– Male
– Requires more aggressive evaluation and follow-up
– Often polymicrobial (E. Coli)
– Pyelonephritis, renal abscess

Question 4

clinical presentation of UTI

Answer 4

– Dysuria
– Urgency
– Frequency of micturition
– Associated pain and discomfort (suprapubic, costovertebral angle)
– Cloudy, blood-tinged urine with strong odor
– Fever, chills, weakness?
– For elderly: asymptomatic, confusion, tachypnea, tachycardia (urosepsis)

Question 5

normal microbes in the urethra

Answer 5

– Lactobacilli
– Streptococci
– Coagulase-negative Staphylococci

Question 6

Lactobacilli

Answer 6

Gram + and non-spore forming
Facultative or strict anaerobes
A low vaginal pH level is an important factor
reducing colonization

usually doesn’t lead to UTI, unless reduced immunity

Question 7

Pyelonephritis (Upper UTI)

Answer 7

infection in both or one kidney

cause:
usually due to ascending infection
Hematogenous spread to the kidneys

acute: due to a bacterial infection due to E.coli

RF: Indwelling urinary catheters, urinary tract obstruction, vesicoureteral reflux, diabetes, pregnancy

chronic: recurrent acute episodes

RF: Vesicoureteral reflux, chronically obstructing kidney stones

Question 8

Cystitis

Answer 8

INF of the bladder
due to E coli mot likely

non-infectious: certain drugs, radiation therapy or potential irritants, long-term catheter use

protective: anti-microbial properties of urine
presence of normal flora
Tamm-Horsfall protein (uromodulin, most abundant protein excreted, constitutive inhibitor of calcium crystallization, defense against UTI)

Question 9

Pyelonephritis (Upper UTI)

Answer 9

infection in both or one kidney

cause:
usually due to ascending infection
Hematogenous spread to the kidneys

acute: due to a bacterial infection due to E.coli

RF: Indwelling urinary catheters, urinary tract obstruction, vesicoureteral reflux, diabetes, pregnancy

chronic: recurrent acute episodes

RF: Vesicoureteral reflux, chronically obstructing kidney stones

Question 10

clinical features of pyelonephritis

Answer 10

Fever
Chills
Nausea; vomiting
Hypotension
Costovertebral angle
tenderness

Question 11

symptoms of cystitis

Answer 11

• Dysuria.
• Urinary urgency and frequency.
• A sensation of bladder fullness or lower abdominal discomfort.
• Suprapubic tenderness.

Question 12

Acute hemorrhagic cystitis

Answer 12

Sudden onset of hematuria combined with bladder pain and irritative bladder symptoms

Clinical features:
•Dysuria
•Urinary frequency, urgency, incontinence

Adenoviruses

Question 13

Cystitis vs Pyelonephritis

Answer 13

A big difference is that hypotension will be seen in pyelonephritis

Question 14

Organisms predominately responsible for remaining UTIs

Answer 14

– Staphylococcus saprophyticus (uncomplicated UTI)
– Klebsiella pneumoniae
– Proteus mirabilis

catheter associated = E coli.

Question 15

Uropathogenic E. coli (UPEC)

Answer 15

Motile, Gram-negative bacilli, facultatively anaerobic, ferment lactose and glucose

+ nitrite test

Key virulence features:
• Type I fimbriae (cystitis)
• P fimbriae (pyelonephritis)
• Lipid A (endotoxic component of LPS)

Question 16

Proteus mirabilis

Answer 16

Gram-negative, facultatively anaerobic
lots of flagella
swarming colonies
can be due to catheter

Virulence factors:
– Proteases
– Hemolysins
– Urease positive
– LPS (lipid A; endotoxin)

Question 17

Staphylococcus saprophyticus

Answer 17

Gram positive cocci, non-motile
usually in sexually active young women

Catalase positive, coagulase negative, Novobiocin resistant, negative nitrite test , urease positive

Clinical Features:
• Dysuria.
• Increased Urinary urgency and frequency.
• Suprapubic tenderness

Question 18

Klebsiella pneumoniae

Answer 18

Facultative anerobic
gram - bacilli
Large mucoid capsulated, non-motile, viscous colonies on MAC, nitrite positive, lactose fermenter, urease positive

can be seen in UTI, pneumonia, and septicemia

• Capsule: anti phagocytotic
• Siderophore: Increased iron binding capacity
• Fimbriae 1/3: attachment
• Biofilm formation: resistance to host cell and antibiotic killing