Urinary tract infection and subclinical bacteriuria Flashcards
Give a definition of urinary tract infection
Urinary tract infection refers to the adherence, multiplication and persistence of an infectious agent within the urogenital system that causes an associated inflammatory response and clinical signs
- more than 99% are caused by bacteria
Give a definition of subclinical bacteriuria
Presence of a significant number of bacteria (>10^3 CFU/ml in a cystocentesis derived urine sample), with or without signs of inflammation in the urine sediment, in an animal that has no clinical signs referable to UTI
Cite the different categories of significant bacteriuria in cats
Sporadic bacterial cystitis
Recurrent bacterial cystitis
Pyelonephritis
Subclinical bacteriuria
Bacteriuria in cats with indwelling urinary catheters
Bacteriuria in cats undergoing urological surgery or minimally invasive urological procedures and/or with urologic implants
Give a definition of sporadic bacterial cystitis
Sporadic (fewer than three episodes in the preceding 12 months) bacterial infection of the bladder with compatible lower urinary tract signs in an animal with or without predisposing factors
Give a definition of recurrent bacterial cystitis and give the subcategories of it
Three or more episodes of clinical bacterial cystitis in the preceding 12 months or two or more episodes in the preceding 6 months
Relapse
- infection with the same microorganism that recurs after successful treatment of the initial UTI
Reinfection
- infection with a different microorganism after the initial microorganism responded to therapy
Persistent infection
- persistently positive urine cultures with the same organism during treatment with appropriate antimicrobial agents
Superinfection
- infection with new organisms that develop during antimicrobial treatment for the initial infecting organism
Give sub-classification of pyelonephritis
Acute pyelonephritis
- uncomplicated: no underlying comorbidity
- complicated: presence of a predisposing systemic disease or an anatomical/obstructive disorder
Chronic pyelonephritis
Give three examples of complicated lower UTI
Emphysematous cystitis
- characterized by gaz accumulation within the bladder wall and lumen secondary to infection with glucose-fermenting bacteria (mainly E. coli)
- animals with diabetes mellitus are predisposed
Encrusting cystitis
- the hallmark of encrusting cystitis is adherent bladder mucosal plaques
- urea-splitting bacteria (e.g., Corynebacterium urealyticum) may lead to mineral precipitation, resulting in bladder wall encrustatio
Polypoid cystitis
- refers to mass-like proliferations or diffuse thickening of the bladder mucosa induced by chronic inflammation
- most commonly associated with Proteus sp. infections
What are the risk factors for UTIs
UTIs are significantly more common in
- spayed female cats
- Abyssinian cats
- cats older than 10 years
A predisposing comorbidity can be identify in 80% of cats with UTI or subclinical bacteriuria
- the most common systemic comorbidities in affected cats are
- CKD
- diabetus mellitus
- hyperthyroidism
What are the major host defences against bacterial colonisation
Frequent and complete voiding of an adequate urine volume
Presence of a normal resident microflora
A physiological urinary tract anatomy
Antimicrobial characteristics of the urine
Systemic immunocompetence
Which pathogen is more often associated with subclinical bacteriuria and what are its characteristics
Enterococcus faecalis is more likely to be present in cats with sub-clinical bacteriuria than in cats with UTIs
E. faecalis has intrinsic resistance to numerous antibiotics including fluoroquinolone
E. faecalis form biofilms and can thus evade antimicrobials
Which examination is important after pyelonephritis treatment and why
Cultures 1-2 weeks post-treatment are recommended
what is the current recommendation of treatment for subclinical bacteriuria
Consider treatment of subclinical bacteriuria only in animals with suspected pyelonephritis, patients undergoing surgical procedures of the urinary tract, patients undergoing endoscopic procedures of the urinary tract, in diabetic animals if subclinical bacteriuria is thought to be the reason for insulin antagonism or ketosis
Is routine culture for CKD cats without clinical signs and without evidence of infection in the urine sediment (hematuria or pyuria +/- bacteriuria) recommended
It is not recommended as most cats with positive urine cultures also have evidence of inflammation in the urine sediment
In CKD cats without any clinical signs but with hematuria or pyuria +/- bacteriuria, urine culture is recommended
- if the culture is positive and it is the first time then treatment could be done
- if culture is positive and the cat a recurrent subclinical bacteriuria with stable renal function then treatment is not mandatory
Treatment of subclinical bacteriuria is typically not warranted if the urine culture reveals growth of Enterococcus species
How would you define pseudomembranous cystitis
Pseudomembranous cystitis is a rare condition
This pathology is associated with severe diffuse ulceration, necrosis, and hemorrhage of the bladder wall, with intraluminal necrotic, fibrinous and hemorrhagic material causing urine outflow obstruction
What is the specific ultrasonographic appearance suggesting pseudomembranous cystitis
The ultrasound examination shows multiple hyperechoic luminal septa and/or strips resembling membranes, associated to urinary bladder wall thickening and intraluminal suspended echogenic debris
