Transcript Urinary Tract Infections Gram negative

Urinary Tract Infections
UTI
• UTI - common affliction for which patients seek medical
attention
• UTI can occur from infancy through old age
• more common in females than males
~20% of all females will experience a UTI during
their lifetime
UTI
Definitions
The term “UTI” represents a wide range of clinical syndromes
Bacteriuria: the presence of bacteria in urine
- does not necessarily imply infection
• Asymptomatic bacteriuria: presence of bacteria in the
urinary tract in the absence of symptoms
- clinical significance controversial outside certain patient
populations
- pregnant women
- patients undergoing invasive procedures
of the urinary tract
UTI
Definitions
• Cystitis: UTI presumed to be confined to the bladder
- painful/burning urination
- urgency or frequency
- absence of symptoms or physical signs suggesting
inflammation at other sites within the urinary tract
• Note: clinical criteria are notoriously inaccurate in
identifying the actual anatomic site of infection
UTI
Definitions
• Pyelonephritis: clinical diagnosis which implies a more
invasive infection
- inflammation of the kidney and renal pelvis is assumed to
be present when patients have pain or tenderness involving
the flank, together with other clinical or laboratory
evidence of UTI
-fever, nausea, chills, malaise, headache, etc
UTI
Definitions
• Prostatitis: inflammation / infection of the prostate gland
- may present as acute or chronic
• Intrarenal abscess / perinephric abscess: collection of pus
in the kidney or in the soft tissue surrounding the kidney
UTI
Definitions
• Complicated infections
- underlying abnormality that predisposes patient to UTI
or makes UTI more difficult to treat effectively
• Recurrent Infections
Relapse - recurrence of infection by same organism after
discontinuation of treatment
Reinfection - recurrence of infection by a different
organism after discontinuation of treatment
UTI
Pathogenesis
• UTI usually due to patients own intestinal flora
- ascending route of infection
- organisms enter the urinary tract in a retrograde
fashion via the urethra
• Complicating factors such as catheters, nephrostomy tubes,
surgery, urinary stones, etc
- allow organisms to enter and persist in urinary tract
- alter the typical spectrum of organisms
- may have multiple etiologies
UTI
Pathogenesis
• Elderly patients
- incontinant
- functionally impaired
- postmenopausal changes
- neurological alterations
• Pregnant women
- altered anatomy
• Hematogenous route
- endocarditis, bacteremias, tuberculosis
- disseminated infections
UTI
Etiology
• Majority of UTI are due to a single pathogen
• The Enterobacteriaceae responsible for 90% of all UTI
- gram negative bacilli
- facultatively anaerobic
- common intestinal flora
• Escherichia coli most commonly isolated pathogen
~80% of all UTI
Community-Acquired UTI
E.coli
S.epi &
gm - enterics
Enterococcus
Proteus
K.pneumoniae S.saprophyticus
Uro-pathogens
• E.coli, Klebsiella spp.
-intrinsic gut organisms
-highly motile
-produce fimbriae (pili) >>attachment
• Proteus, Morganella, Providencia
-Urease producing organisms
-increases urinary pH - leads to crystal formation
>>biofilms
>>colonization of catheter
>>protects bacteria from host defenses & antibiotics
Nosocomial UTI
catheter associated
Short Term
Long Term
E.coli
Enterococcus
Enterobacter
E.coli
Proteus
Candida
Proteus
Providencia
Morganella
S.aureus
Pseudomonas
Pseudomonas
Urinalysis
• usually have increased numbers of WBC
• leukocyte esterase test is often positive
• nitrate test is often positive
Urinalysis
• Urine culture: significant bacteriuria usually defined as
> 105 bacteria / ml. (108 / litre)
• lower numbers may be significant in children and in
catheter collected specimens
Specimen collection
• Should all patients with a suspected UTI be cultured?
• Community acquired vs nosocomial?
• Should all isolates be identified?
Susceptibility testing?
Specimen collection
• Clean catch mid stream specimens
- most frequently used method
- urethra cleaned prior to collection
- first void urine allowed to pass to clear urethra
- mid-stream collected in sterile container
• Collection bags (children)
- used in young children lacking bladder control
- often contaminated
- most meaningful result is a negative culture
Specimen collection
• Suprapubic aspiration / straight catheters
- invasive
- specimen obtained directly from bladder
• Indwelling catheters
- urine obtained by inserting needle into catheter or
through diaphram
- preferable to obtain specimen from new catheter, rather
than old catheter
Specimen transport
• Sent to and processed by lab as quickly as possible
- Require: method of collection
time of collection
patient’s antibiotics
• Specimens not received by lab in 1-2 hours MUST be
refridgerated
• Urines not received within 24 hours or not refridgerated
will be rejected by laboratory
Antimicrobial Therapy
• Empiric Therapy
- based on most probable pathogens
- local rates of resistance
- acute infection vs chronic
- reinfection or relapse
- indwelling catheter etc
Management of UTI
• Anatomical/Functional Predisposition to
UTI
– Impaired bladder emptying
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Dysfunction
Neuropathy
VUR
BOO
Diverticulum
Management of UTI
• Anatomical/Functional Predisposition to
UTI
– Obstruction
• Any level
– VUR
– Calculi
• very difficult to eradicate if UTI and stones
Management of UTI
• Anatomical/Functional Predisposition to
UTI
– Intrarenal
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Renal scars
Interstitial nephritis
Papillary necrosis
Medullary sponge kidney
APKD
Congenital calyceal obstruction
Management of UTI
• Anatomical/Functional Predisposition to
UTI
– Associated conditions
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Diabetes mellitus
Pregnancy
Immunosuppression
Elderly
Management of Female UTI
• Bacterial Factors
– Adherence
• Adhesins
• Fimbriae
• Non-fimbrial Adhesins
– Biofilms
• Important in catheter UTI
– Soluble Virulence Factor Production
• Disrupt bladder protective mucus layer
Management of Female UTI
• Bacterial Factors
– Iron Acquisition Mechanisms
• Siderophores and Haemolysins
• Allow growth
– Serogroup and Serum R
• O ag LPS outer G -ve
• Prevent complement destruction
– Capsules
• K ag covers bacteria capsule
• Protects v phagocytosis and complement attack
Management of Female UTI
• Bacterial Factors
– Ig Proteases
• Cleave gut IgA
– Ureteric Paralysis
• P. Fimbriae and endotoxin
– Motility
• Ascent of LUT
– Urease Production
• Hydrolyse urea and increases ammonia which
increases bacterial adherence
Management of Female UTI
• Host Factors
– Colonisation of vagina, introitus, urethra
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Biological predisposition
Hormone deficiency vaginal atrophy
Spermicidal jelly increases vaginal pH
Antibiotics reduce vaginal lactobacilli and increase
pH
– Ascent to bladder
• Sexual milkback
• Catheterisation
Management of Female UTI
• Host Factors
– Establishment of bacteria in bladder
• Urine composition (extremes inhibit bacterial
growth)
• Reduced IgA and IgG
• Reduced GAG layer in the bladder
• Low urine flow
• Incomplete emptying
Management of Female UTI
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MSSU when symptomatic
USS renal tract with post void residual
KUB
Targeted flexible cystoscopy (8% yield)
– macroscopic haematuria
– microscopic haematuria between UTIs
– persistent UTI
Management of Female UTI
• 3 days oral antibiotics or x1 high dose if
compliance poor
• 14 days antibiotics if pyelonephritis
• Address any underlying cause (rare)
• General advice
– increase fluid intake
– cranberry juice
– void before and after si
Management of Female UTI
• Hygiene
– wash without soap
– pat or air dry
– cotton pants
• 6 months low dose prophylactic antibiotics
– alter gut flora
– may affect COCP
• Self-start antibiotic therapy
Management of Male UTI
• MSSU when symptomatic
• USS renal tract with flow rate and post void
residual
• KUB
• Flexible cystoscopy
– macroscopic haematuria
– microscopic haematuria
– persistent UTI
Management of Male UTI
• UTI - 7 days oral antibiotics
• Address underlying cause
Management of Childhood UTI
• History
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fevers and rigors
irritative LUTS
incontinence
change in voiding pattern
bowel dysfunction
• Examination
– including neurology
Management of Childhood UTI
– TREAT IMMEDIATELY AFTER MSSU
COLLECTED WITH THERAPEUTIC
ANTIBIOTICS AND CONTINUE
PROPHYLACTIC ANTIBIOTICS UNTIL
INVESTIGATIONS COMPLETED
– ONLY DISCONTINUE IF ALL
INVESTIGATIONS NEGATIVE
Management of Childhood UTI
• MSSU/Suprapubic aspiration/Bladder
catheterisation when symptomatic
• USS renal tract with post void residual
• DMSA/MAG3 (if hydronephrosis)
• VCUG (if DMSA or MAG3 +ve)
– at least 6 weeks post UTI
• KUB (if ? SB/sacral agenesis)
• MRI (if spinal anomalies)
Management of Childhood UTI
• UTI
– 3-5 days antibiotics
• Pyelonephritis
– non-toxic/ > 3 months : im ab x1 + 10-14 days
antibiotics
– toxic/ < 3 months: iv antibiotics + 10-14 days
antibiotics when stable
• Asymptomatic bacteriuria: no treatment
unless have VUR
• Thank you!