Rational Antimicrobials 5 Flashcards
most frequently isolated bacteria in UTIs is
E.coli
§ Uropathogenic E.coli account for a lot of UTIs
bacterial cystitis - what animals is it common in?
§ 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
in ruminants, bacterial cystitis is associated with:
n ruminants, bacterial cystitis is associated with catheterization or parturition, or urolithiasis in males
in horses, bacterial cystitis is associated with:
Bacterial cystitis in horses is uncommon and associated with bladder paralysis, urolithasis or urethral damage
Bacterial UTI diagnosed how? for cats and dogs:
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
best method for obtaining a urine sample when looking for bacterial UTI?
§ cystocentesis is the best method for obtaining a urine sample
what urine results support becterial UTI?
§ hematuria, pyuria, bacteriuria and proteinuria supports bacterial UTI
clinical signs of bacterial UTI?
§ Clinical signs: pollakiuria, dysuria, stranguria, hematuria
what is sporadic bacterial cystitis
§ 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
If urine from a UTI is alkaline, what do we suspect?
suspect urease producing pathogens
§ Staphylococcus (cocci)
§ Proteus (rods)
If urine from a UTI is acidic, what do we suspect?
likely pathogens
§ E.coli (rods)
§ Enterococcus (cocci)
§ Streptococcus (cocci)
what are the keys to developing a bacterial cystitis (UTI) and the persistence of challenging UTIs?
Underlying pathology and/or abnormalities of host defences involving the urinary tract
most common agents implicated in bacterial UTIs
- E. coli
- S. pseudintermedius
- Enterococcus spp.
- proteus spp.
- streptococcus spp.
- staphylococcus spp.
staph pseudointermedius UTI: treatment and antimicrobial choice? what should we keep in mind about antimicrobial choice?
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
when treating a UTI: What if my empiric therapy shows “R” on C/S, but Cx signs are resolving? what if signs not resolving?
- 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
what monitoring is needed when treating bacterial UTI?
- 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
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?
- 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?
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?
-free catch sample, probably
Urine collection recommendations: how to collect, how to ship urine? pros and cons of different methods? what are considered significant results?
- 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
what do we do with an enterococcus UTI case?
- 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
Recurrent UTI definition
involve 3 or more episodes of UTI in the preceding 12 mos, or 2 or more in the preceding 6 mos
>relapses or reinfections
what is a UTI relapse?
- 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
what is a UTI reinfection (vs relapse)?
- reinfections are similar to relapses, but……
> isolation of a different organism (species or strain)
> usually re-inoculation of the urinary tract by GI flora
what is a refractory UTI?
similar to relapse except no period of elimination of bacteriuria during treatment
Subclinical bacteriuria; what is this, what do we do?
- 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
issues with indwelling urinary catheters and UTIs? when should we treat associated issues?
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
