Microbiology 10 - Urinary Tract Infections Flashcards
Which organism is the most common cause of UTI?
E coli (95%)
What are the symptoms of UTI in babies?
Vomiting and failure to thrive
What are the symptoms of pyelonephritis?
Fever, rigors, flank pain and urinary symptoms
What are squamous epithlial cells in a MSU indicative of?
Contamination
For how long should antibiotics be taken in uncomplicated UTI?
3 days
What is the most common route of infection for candida UTIs?
Urinary catheters
note oral fluconazole is not useful
do not treat asymptomatic fungal infection
What is the empirical antibiotic treatment for pyelonephritis?
Co-amoxiclav +/- gentamycin
what’s the 2nd most common cause of UTI in younger women`?
staph saprophyticus (coagulase -ve staph)
what organism causes UTI in presence of prosthesis?
staph epidermis
e.g in a long term catheter
are the urethra and bladder sterile?
urethra - not
bladder is sterile
define complicated vs uncomplicated UTI? in whom is it complicated
complicated =infection w functional or structural abnormalities
complicated = men, pregnancy women, children (not young girls), patient in healthcare setting
uncomplicated = infection in a structurally and neurologically normal urinary tract
what does e coli have to prevent it being flushed out of urine
adherence factors
what type of cells at end of urethra
squamous epithelial
if found in MSU sample hasn’t been taken properly
fever is absent in what type of UTI?
lower
what are lower UTI symptoms
FUND - Storage/Irritative Frequency Urgency Nocturia Dysuria
HIPS Voiding/Obstructive Hesitancy Incomplete emptying Poor stream Straining Others: terminal dribbling, overflow incontinence
what’s the treatment of pyelonephritis
prior to culture results - amoxicillin
if results - coamox w/wout gentamicin
what investigations for a UTI/pyeloneph
Urine dipstick
- MSU for urine microscopy, culture and
sensitivities
- Bloods – FBC, UE, CRP (inflammatory
markers and renal function)what investigations for a complicated UTI/pyeloneph
Renal USS
Intravenous urography
negative nitrites & leucocyte esterase =
unlikely infection
if either nitrite or lecuocyte esterase are positive and patient is symptomatic?
start antibiotics and send culture
2 treatment options of uncomplicated UTI in female
nitrofurantoin 50mg QDS 7days
OR
cephalexin 500mg BD 3 days
treatment of UTI if pregnant or breastfeeding
1st = Nitrofurantoin (avoid at term) 100mg modified-release twice a day for 7 days if egfr is above 45 2nd = cephalexin 500mg BD for 7 days
treatment of UTI in a male
cephalexin 500mg BD 7days
treatment of catheter associated UTI
Nitrofurantoin (if eGFR ≥45ml/minute) 100mg modified-release twice a day for 7 days.
Trimethoprim (if low risk of resistance) 200mg twice a day for 7 days.
Amoxicillin (only if culture results available and susceptible) 500mg three times a day for 7 days.
are more organisms needed to infect medulla or cortex
few = medulla
many (10,000 x) = cortex
give 4 complications of pyelonephritis
Perinephric abscess
Chronic pyelonephritis (scarring, chronic renal impairment)
Septic shock
Acute papillary necrosis
upper UTI symptoms
similar to lower
also fever
flank pain
what culture results are diagnostic of a UTI
over 10^5 CFUs/mL
give 3 Antibacterial Host Defences in the Urinary Tract
Urine (osmolality, pH, organic acids)
Urine flow and micturition
Urinary tract mucosa (bactericidal activity, cytokines)
what condition increases the risk of ascending UTI in women
vesicoureteric reflux
what is sterile pyuria? give 5 causes
raised WCC but no growth on culture prior ABx treatment - most common Catheter TB STI - chlmaydia calculi
pink agar is what bacteria
e coli
light blue agar is what group of bacteria
gram negative
what agar is used to identify causes of UTI
chromogenic agar (changes colour)
give 2 extra renal causes of obstruction that may lead to UTI
BPH
calculi
give 2 intra renal causes of obstruction that may lead to UTI
PKD
nephrocalcinosis
give 2 neurogenic causes of obstruction that may lead to UTI
diabetic neuropathy
tabes dorsalis
define recurrent UTI
Recurrent UTI in adults is defined as repeated UTI with a frequency of 2 or more UTIs in the last 6 months or 3 or more UTIs in the last 12 months.
