Urinary Tract Infections

Question 1

describe local and systemic host defenses of the urinary tract against infection

Answer 1

local defenses:
1. microflora
2. mechanical: peristalsis, urethral length, unidirectional voiding
3. mucosal barriers: GAG, secretory IgA, epithelial exfoliation
4. urine characteristics: high osmolality, high urea concentration, organic acid

systemic defenses: humoral and cellular immunity

Question 2

describe what determines if a microbe will cause an infection?

Answer 2

1. virulence and other fitness factors
   -pathogenic features
   -biofilm formation (unsure how much contributes to infection rn in vet med)

Question 3

describe common signs of UTIs

Answer 3

1. straining when urinating (stranguria)
2. licking around the genital area
3. decreased urine flow
4. frequents attempts to urinate (pollakuria)
5. incontinence
6. blood in urine (hematuria; not specific to LUT)

or could be subclinical!!

Question 4

how to diagnose UTI?

Answer 4

1. collect urine sample 3-5ml
   -cystocentesis is best way to collect FOR CULTURE
2. hematuria: >5-10 RBC/hpf
3. pyuria: >5 WBC/hpf
4. bacteria: can be hard to see! need to stain (unstained positive predictive value is only 40%)
   - >10,000-100,000 cfu/ml

Question 5

how to determine if bacteruria is real or not real?

Answer 5

1. stain it! (Wright’s stain)
2. culture it

Question 6

describe line smear microscopic exam of urine sample

Answer 6

1. place drop toward frosted end
2. take another slide, hold at steeper angle than blood smear
3. when get to middle of slide, lift up
4. stain: bacteria line up
   -a way to concentrate and stain bacteria! for the cost of a slide and can use oil since not using cover slip

Question 7

describe urine culture

Answer 7

the gold standard! can even do in practice

1. streak with calibrated loop
2. blood agar or blood agar + on MacConkey
3. incubate in incubator or place under 60W bulb for 38C surface temp for 24-48 hours and check for growth; if no growth, no infection, if there is growth, can send to lab for susceptibility!

Question 8

describe point of care tests for UTIs

Answer 8

1. can point of care culture
2. don’t give susceptibility though!
3. tabletop PCR machines for in practice exist!
   -picks up specific organisms, but doesn’t tell if alive or dead

Question 9

what organisms cause active UTIs?

Answer 9

1. E. coli!!!!!!!!!
2. gram + cocci
   -staphylococcus (alkaline urine), streptococcus, enterococcus
3. miscellaneous:
   -proteus, klebsiella, pasteurella, pseudomonas, corynebacterium, mycoplasma, ureaplasma

Question 10

what are the 4 categories of clinical, real, bacteruria?

Answer 10

1. sporadic bacterial cystitis
2. recurrent bacterial cystitis
3. upper bacterial UTI
4. bacterial prostatitis

Question 11

describe diagnosis of sporadic bacterial cystitis

Answer 11

1. LUT signs
2. frequency:
   - <3 infections within 12 months and no more than 2 in previous six months
3. UA: bacteria, white cells, red cells
4. culture: positive
   -cysto collection is best
   -NOT voided sample
5. casts: can confirm urine culture/sensitivity
6. consider comorbidities

Question 12

describe treatment of sporadic bacterial cystitis

Answer 12

1. anti-inflammatories: inflammation in response to bacteria is what causes clinical signs!!
   -NOT steroids (don’t want to suppress immune system)
2. antibiotic therapy:
   -empiric while wait for C&S or if don’t culture: amoxicillin, clavamox, trimethoprim-sulfa
   -then based on urinary C & S
   -length: 3-5 days (clin signs should get better in 2-3 days if you are right about abx choice, if not, rethink and try different approach)
   -NOT

Question 13

describe follow up for sporadic bacterial cystitis

Answer 13

1. eval after at least 48 hours
   -if no signs, good job and no further culture or tx needed
2. if signs: do another C&S to check for resistance and if need to change abx
3. avoid antibiotic alphabet game!!

Question 14

describe recurrent bacterial cystitis

Answer 14

1. at least 3 within 12 month period and more than 2 within last 6 months
2. repeat antibiotics will likely not cure!!
   -there is something else going on!!
3. diagnosis:
   -culture!!!!
   -ID and manage risk factors
4. if clinical signs with a negative culture: bladder biopsy
5. for relapsing/refractory/persistent:
   -need to be very careful with using correct antibiotic (bug, drug, rug)
6. can be due to:
   -recessed vulva
   -ectopic ureter
   -indwelling catheter
   -polyps
7. deep seated infections can be due to:
   -L/P urethritis/cystitis
   -polypoid cystitis
   -bladder TCC
   -pyelopnephritis
   -urolithiasis
   -prostatis
   -uterine infection
8. can also be related to systemic diseases:
   -diabetes mellitus
   -hyperadrenocorticism: dogs
   -hyperthyroidism: cats
   -renal failure
9. bacterial factors:
   -antimicrobial resistance
   -unusual organism

Question 15

describe treatment of recurrent bacterial cystitis

Answer 15

1. 5-7d (dead bugs won’t mutate, if it kills it kills)
   -right bug, drug, rug
2. analgesics +/- empiric WHILE WAITING for culture!! You NEED to culture
3. ID and control comorbidities

Question 16

describe follow up for recurrent bacterial cystitis

Answer 16

1. eval in 48 hours
2. if culture and find resistance, change abx
3. avoid abx alphabet game!