Rational Antimicrobials 5

Question 1

most frequently isolated bacteria in UTIs is

Answer 1

E.coli
§ Uropathogenic E.coli account for a lot of UTIs

Question 2

bacterial cystitis - what animals is it common in?

Answer 2

§ Sporadic bacterial cystitis is a common condition in dogs and occasionally encountered in cats; generally in older cats vs the young
§ Prevalence of bacterial cystitis is very low in cats (particularly young cats) presenting with an initial episode of signs related to lower urinary tract disease

Question 3

in ruminants, bacterial cystitis is associated with:

Answer 3

n ruminants, bacterial cystitis is associated with catheterization or parturition, or urolithiasis in males

Question 4

in horses, bacterial cystitis is associated with:

Answer 4

Bacterial cystitis in horses is uncommon and associated with bladder paralysis, urolithasis or urethral damage

Question 5

Bacterial UTI diagnosed how? for cats and dogs:

Answer 5

urine examination and microbiological culture
> cystocentesis is the best method for obtaining a urine sample
§ complete U/A, urine sp. gr., urine glucose and sediment exam including presence of crystals……….minimum database
§ Aerobic culture should be performed in cats; empiric tx in lieu of
§ culture in dogs with sporadic cystitis is acceptable

Question 6

best method for obtaining a urine sample when looking for bacterial UTI?

Answer 6

§ cystocentesis is the best method for obtaining a urine sample

Question 7

what urine results support becterial UTI?

Answer 7

§ hematuria, pyuria, bacteriuria and proteinuria supports bacterial UTI

Question 8

clinical signs of bacterial UTI?

Answer 8

§ Clinical signs: pollakiuria, dysuria, stranguria, hematuria

Question 9

what is sporadic bacterial cystitis

Answer 9

§ otherwise healthy non-pregnant female or neutered male
§ no known anatomical or functional urinary tract abnormalities or relevant comorbidities
§ fewer than 3 episodes of known or suspected bacterial cystitis in preceding 12 months

Question 10

If urine from a UTI is alkaline, what do we suspect?

Answer 10

suspect urease producing pathogens
§ Staphylococcus (cocci)
§ Proteus (rods)

Question 11

If urine from a UTI is acidic, what do we suspect?

Answer 11

likely pathogens
§ E.coli (rods)
§ Enterococcus (cocci)
§ Streptococcus (cocci)

Question 12

what are the keys to developing a bacterial cystitis (UTI) and the persistence of challenging UTIs?

Answer 12

Underlying pathology and/or abnormalities of host defences involving the urinary tract

Question 13

most common agents implicated in bacterial UTIs

Answer 13

• E. coli
• S. pseudintermedius
• Enterococcus spp.
• proteus spp.
• streptococcus spp.
• staphylococcus spp.

Question 14

staph pseudointermedius UTI: treatment and antimicrobial choice? what should we keep in mind about antimicrobial choice?

Answer 14

Treatment:
- Stone dissolving diet
- Antibiotic choice recommended by guidelines > use amoxicillin alone, and clavamox is a reasonable choice if amoxicillin is not available
- Duration of therapy: 7 days
- Client compliance is important !!

> our suscpetibility report may say R for amicillin (also represents result for amoxicillin and hetacillin)
these drugs are eliminated unchanged in the urine and acheieve very high concentrations in the bladder
R is for blood, not urine

Question 15

when treating a UTI: What if my empiric therapy shows “R” on C/S, but Cx signs are resolving? what if signs not resolving?

Answer 15

• continue with original choice if signs resolving
  > ensure you do a followup urinalysis and culture after treatment to ensure resolutoin of the infection

-if signs not resolving:
> do not switch from original antibiotic of choice
> further workup is needed, unless poor compliance or some mistake has been made

Question 16

what monitoring is needed when treating bacterial UTI?

Answer 16

• for sporadic, no followup is needed provided treatment is complete and clinical signs have resolved
• with complicated / recurring cases, C/S 5-7d after initiating treatment is recomended, and 7d after treatment is completed
• lack of bacterial response within 48h of starting therapy should prompt investigation

Question 17

case: dog with recurring UTI, treated with clavaseptin, was doing well but now urinating frequently again. she is just a puppy.
> what do we do when the infection does not resolve?

Answer 17

• this is a puppy, and our previous choice of AB was appropriate
  > think anatomical problem!
  > dont waste money with antibiotics, will just cause resistance
  > shows value of initial C/S - was this E. coli ever susceptible, if it is not now?

Question 18

CASE:
- 7.5 yr old Canine FS German Shepherd
- Routine wellness exam indicated calcium oxalate crystals on U/A
- C/S done on free-flow urine sample
> we see many pathogens, why?

Answer 18

-free catch sample, probably

Question 19

Urine collection recommendations: how to collect, how to ship urine? pros and cons of different methods? what are considered significant results?

Answer 19

• Refrigerate immediately; ship as quickly as possible (within 24 hrs) to lab
• Cystocentesis sample is recommended unless contraindicated
• ≥10^3 cfu/mL bacterial counts deemed significant
• Catheterized sample
• ≥10^4 cfu/mL for males; ≥10^5 cfu/mL for females
• positive cultures should be confirmed by cystocentesis unless medically
  contraindicated
• Free-flow (midstream) sample; refrigerate and ship within a few hours to lab for culture
• ≥10^5 cfu/mL and pure growth of common uropathogens
• contamination a concern
• positive cultures should be confirmed with cystocentesis unless medically contraindicated

Question 20

what do we do with an enterococcus UTI case?

Answer 20

• problematic as broad resistance profile, and readily acquire resistance genes
  > these are not problematic in GI tract but can cause problems in other parts of the body
  > chloramphenicol & nitrophurintone are often good choices
  > chloramphenicol has some negative effects for humans and animals

Question 21

Recurrent UTI definition

Answer 21

involve 3 or more episodes of UTI in the preceding 12 mos, or 2 or more in the preceding 6 mos
>relapses or reinfections

Question 22

what is a UTI relapse?

Answer 22

• isolation of an indistinguishable organism from previous one
• tend to occur faster than reinfections ie. days to weeks vs months
• period of bladder sterility during treatment

Question 23

what is a UTI reinfection (vs relapse)?

Answer 23

• reinfections are similar to relapses, but……
  > isolation of a different organism (species or strain)
  > usually re-inoculation of the urinary tract by GI flora

Question 24

what is a refractory UTI?

Answer 24

similar to relapse except no period of elimination of bacteriuria during treatment

Question 25

Subclinical bacteriuria; what is this, what do we do?

Answer 25

• Presence of bacteria in urine based on positive culture, but the absence of clinical evidence of UTI
  > treatment is rarely indicated and generally discouraged
  > treatment considered if concern of ascending or systemic infection
  -Should not automatically assume bacteriuria indicates cystitis and a need
  to treat

Question 26

issues with indwelling urinary catheters and UTIs? when should we treat associated issues?

Answer 26

UTIs and subclinical bacteriuria often associated with indwelling catheters
- Routine culture for presence of bacteriuria not recommended in the absence
of clinical signs suggesting an active infection

• Not necessary to treat bacteriuria with no supporting clinical evidence of an infection
• Prophylactic antimicrobials not appropriate for prevention of a UTI from indwelling catheter

-If infection suspected then culture of urine collected by cystocentesis recommended
> Catheter removal best for successful treatment