Urinary Tract Infections

Question 1

Urinary Tract Infections (General)

Answer 1

• very common bacterial infection
• more frequent in women due to anatomic difference
• can be single, recurrent, uncomplicated or complicated
• Urinary tract normally resistant to infection due to urine characteristics

Question 2

Upper UTI’s

Answer 2

infection of renal parenchyma or ureters

Question 3

Lower UTI’s

Answer 3

infection of bladder, urethra or prostate (males)

Question 4

Recurrent UTI’s

Answer 4

• Relapse: re-infection with the same bacteria

- Reinfection: second UTI infection by different organism

Question 5

Uncomplicated UTI’s

Answer 5

UTI’s in sexually active women with normal GU tracts; no procedures

Question 6

Complicated UTI’s

Answer 6

UTI’s due to one or more structural or functional abnormalities

Question 7

Urine infection resistance

Answer 7

• extremely high osmolarity to inhibit growth of most organisms
• low pH
• dilute urine grows less
• prostatic fluid (men)
• flow has washing affect to inhibit adherence

Question 8

UTI Risk factors

Answer 8

• AGE (kids with long-term medical problems, adults with GU abnormalities, elderly because of catheterization, prostate problems, bladder prolapse)
• INSTITUTIONALIZE CARE (catheters, asymptomatic bacteruria)
• PREGNANCY (increased ASB)
• RENAL TRANSPLANT (leads to septicemia)
• BLADDER CATHETERIZATION

Question 9

Route of Infection

Answer 9

• Ascending route: most common route, migration from bladder, acquired UTI’s
• Descending route: infection via blood, < 5% of UTI’s

Question 10

UTI’s (Clinical Signs/Symptoms)

Answer 10

• failure to thrive, vomiting, lethargy, fever in kids < 2 y/o
• dysuria, frequency and abdominal/flank pain in kids
• dysuria, frequency, urgency, suprapubic pain, hematuria in adults
• fever, costovertebral angle tenderness, flank pain, chills, vomiting in upper UTI’s

Question 11

Infections in urine cultures that aren’t UTI’s

Answer 11

• Herpes simplex (HSV)
• Chlamydia trachomatis
• Neisseria gonorrhoeae

Question 12

UTI pathogenesis (women)

Answer 12

• infection via ascending route

- due to shorter ureter

Question 13

UTI pathogens

Answer 13

• Gram-positives (S. sapro, Enterococcus, S. epi) via ascending route
• Gram-negatives (E. coli, Pseudomonas, Proteus, Kleb, Acinetobacter, Enterobacter) via ascending route - from catheterization (except E. coli)
• GPR’s (Bacillus, MAC, Listeria)
• Chlamydia, N. gonorrhoeae, Mycoplasma, Ureaplasma, Gardnerella, Adenovirus, HSV
• Bacteremias, endocarditis, , mycobacteria, Candida, fungal infections via hematogenous route

Question 14

UTI virulence factors

Answer 14

• adherence
• biofilms
• calculi formation

Question 15

• Gram positive cocci
• catalase positive, coagulase negative
• Bacitracin resistant, Novobiocin resistant

Answer 15

S. saprophyticus

Question 16

• Gram positive cocci
• catalse -
• Bile esculin +, growth in 6.5% NaCl, PYR +

Answer 16

Enterococcus

Question 17

• Gram positive cocci
• catalase +, coagulase -
• Bacitracin resistant, Novobiocin susceptible

Answer 17

S. epidermidis

Question 18

• GNR
• oxidase -, glucose fermenter, nitrate reducer, motile
• IMVC (++–)
• H2S -, citrate -, PAD -, A/A

Answer 18

E. coli

Question 19

• blue-green hue on MAC (pyoverdin and pyocyanin)
• beta hemolytic
• oxidase +, catalase +, ADH +, citrate +
• glucose oxidizer
• grows at 42C

Answer 19

P. aeruginosa

Question 20

• GNR
• H2S +, swarm, PAD +, urease +
• vulgaris (indole +, ODC -, A/A)
• mirabilis (indole -, ODC +, K/A)

Answer 20

Proteus

Question 21

• GNR
• citrate +, H2S -, PAD -, urease -, IMVC (–++)
• oxytoca (indole +)

Answer 21

Klebsiella

Question 22

• GNR
• oxidase -, glucose oxidizer
• NLF, but purple on MAC

Answer 22

Acinetobacter

Question 23

• GNR
• oxidase -, IMVC (–++), LDC + (except cloacae), ODC +
• citrate +, H2S -, PAD -, urease -

Answer 23

Enterobacter

Question 24

• Gram positive bacilli
• grows at 4C, catalase +
• umbrella motility at 25C, tumbling motility
• CAMP positive (block)

Answer 24

Listeria

Question 25

- Gram positive bacilli - motile, beta hemolytic - catalase positive

Answer 25

Bacillus (cereus)

Question 26

- inactive in most tests - heat-stable catalase - common Mycobacteria in US

Answer 26

M. avium complex (MAC)

Question 27

- intracellular parasites - specimen on Dacron swab - EB and RB stages of life cycle - won't grow on a normal plate

Answer 27

Chlamydia trachomatis

Question 28

- Gram negative dipplococci - oxidase - - grows on MTM - utilizes glucose

Answer 28

Neisseria gonorrhoeae

Question 29

Lab Diagnosis of UTI

Answer 29

- colony count: leukocyte count at least 10/mm^3 in more than 96% of patients with bacteruria - Urine culture and other tests for diagnosis

Question 30

Types of urinary infections (women)

Answer 30

- Symptomatic pyuria without bacteruria | - Asymptomatic bacteruria (with or without pyuria)

Question 31

Specimen collection

Answer 31

- Voided midstream specimen collection (CCMS) - Catheterized specimen collection (best for kids) - Suprapubic aspiration (for anaerobes) - 24hr old specimen is unacceptable - first morning urine is best

Question 32

Specimen processing

Answer 32

- processed within 2 hours - refrigerated if not processed immediately - avoid contamination of specimen - rapid nonculture screening or manual screening

Question 33

Microscopy

Answer 33

- pyuria: 5-10 leukocytes in urine - detect fungi and mycobacteria (use acid fast stain) - chemical tests

Question 34

Specimen rejection

Answer 34

Reject if inadequate collection/transportation

Question 35

Culturing urine specimens

Answer 35

- usually BAP and MAC - incubate 24 hours - plate to more plates for fastidious organisms

Question 36

Interpreting culture results

Answer 36

- colony count indicates level of pyuria | - presence of symptoms also indicative

Question 37

Culture with 3 or more uropathogens

Answer 37

probably contamination

Question 38

Culture with 2 significant uropathogens (>10^5)

Answer 38

identify and perform susceptibility

Question 39

Culture with 1 or 2 uropathogens (small numbers >10^2)

Answer 39

identify if clinical situation warrants

Question 40

Reportable results

Answer 40

- a pure culture of S. aureus is significant - yeast in any culture is significant - unusual organisms are reportable - only report significant UTI antibiotics