UTIs Flashcards
Bladder tenesmus
Incomplete voiding
Dysuria
Pain or discomfort when urinating
Bacteriruia
The presence of bacteria in urine
Does not necessarily imply infection
Asymptomatic bacteruria
and when is it clinically significant
Presence pf bacteria in the urinary tract in the absence of symptoms
Problems in pregnant women, or patients undergoing invasive procedures of the urinary tract)
Normal mechanisms that maintain sterility of urine
Adequate urine volume
Free-flow from kidneys through urinary meatus
Complete bladder emptying
Normal acidity of urine
Peristaltic activity of ureters
Increased intra-vesicular pressure preventing reflux
In males, antibacterial effect of zinc in prostatic fluid
What are upper or lower UTIs called?
Upper: Pyelonephritis
Lower: Cystitis and urethritis
Cystitis (and 3 most common symptoms)
UTI presumed to be confined to the bladder
Most common symptoms: dysuria, urinary frequency, urinary urgency
Can have NO signs that suggest a systemic infection
Very rarely have a fever
What two bacteria mimic symptoms of a lower UTI
Chlamydia trachomatis
Neisseria gonorrhoeae
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 lab evidence of UTI
Systemic findings: fever, flank pain, nausea, chills, malasie, headache, etc
Prostatitis
Inflammation/infection of the prostate gland
May be present as acute or chronic
Can be hard to treat because you dont get great levels of antibiotics here
Intrarenal abscess/perinephric abscess
Collection of pus in the kidney or in the soft tissue surrounding the kidney
Uncomplicated UTIs
Occurs in patients with normal genitourinary tracts
Usually non-pregnant premenopausal women of childbearing age
Complicated UTIs
Structural or functional abnormality of the genitourinary tract
Pregnant women, elderly, men, and children
Chronic symptoms
Comorbid illness (ex: diabetes) or immuno-compromised
Upper tract disease (pyelonephritis)
Any underlying abnormality that predisposes patient to UTI or makes UTI more difficult to treat effectively
Relapse
Recurrence of infection by same organism after discontinuation of treatment
May be due to resistance
Re-infection
Recurrence of an infection by a different organism after discontinuation of treatment
Might be some factor that disposes the patient to UTIs
Risk factors
Aging (diabetes, urinary stasis, impaired immune response, incontinence)
Female (short urethra, sex, birth control, pregnancy)
Male (prostatic hypertrophy, anal intercourse)
Urinary tract obstruction (tumor or calculi, strictures)
Impaired bladder innervation
Hematogenous spread
What family and species is most common for UTI
The Enterobacteriaceae is responsible for 90% of all UTIs (gram negative, facultatively anaerobic, common intestinal flora)
Escherichia coli is most commonly isolated pathogen (70%)
What are some virulence factors
Adherence (major)
Motility
P fimbria (bind to P blood group antigen on uro-epithelial cells)
Hemolysins, colicin V (aid in resistance to complement dependent bactericidal effect of serum)
K antigen (associated with upper tract infections)
Type 1 fimbria (interbacterial binding and biofilm formation)
3 classical uro-pathogens
Proteus, Morganella Providencia
Urease producing organisms
Increases urinary pH (leads to crystal formation/struvite stone formation that provides substrate for biofilm)
Highly motile, produce fimbria for attachment
Staphylococcus saphrophyticus
Coagulase negative
Typically associated with younger, sexually active females
1-5% of cystitis
Identified in the lab using resistance to novobiocin
Dipstick testing
Primarily interested in the detection of nitrites and leukocytes produced by infection
Detecting nitrites is not sensitive but is specific
Detecting leukocytes is sensitive but not specific
Combined is great!
RBC detection is not sensitive or specific
Sensitivity versus specificity
Sensitivity is the ability of a test to correctly identify those WITH the disease
Specificity is the ability of the test to correctly identify those WITHOUT the disease
Chromogenic media
Has certain substances that certain bacteria will use and then change colour
Can tell what bacteria it is just by looking at the colour
2 things you MUST have labelled on specimen
Method of collection
Time/date of collection
Boric acid tube
Maintains availability of the urine for about 48 hours
Good for those in remote communities
3 drugs to treat uncomplicated cystitis
Nitrofurantoin
Fosfomycin
Septra (but a lot of resistance, so not anymore)
2 drugs to treat pyelonephritis
Ciprofloxacin
Beta lactam and an aminoglycoside
Urine culture
Use SBA and MacConkey plate
What is the most common pathogen you’re going to culture from a young women?
E. coli!
