Host defenses in the urinary tract
pH < 5.5, High urea, Flushing mechanisms of urine
Cystitis Definition
infection of the bladder
Urethritis Definition
infection of the urethra
Prostatitis Definition
infection of the prostate
Pyelonephritis
infection of the kidney (“upper UTI”)
Symptoms of urethritis and cystitis (LOWER UTIs)
BIG 3 Dysuria, frequency and urgency, Urine may be cloudy or hematuria, USUALLY NO DISCHARGE (differential from STD)
Symptoms of prostatitis
Lower back, perirectal and testicular pain
Symptoms of pyelonephritis
Pain in FLANKS + FEVER, Also frequency, urgency, dysuria precede
Pyuria
more than 10 wbc per cubic millimeter of urine
Dip Stick Components (2)
Test for ESTERASE (pyuria) and NITRITE (E. Coli)
Indication of Significant Bacteriuria
Presence of at least one bacterium per microscopic oil-immersion field (100,000 Colony Forming Units/mL), culture to find causative agent
How much more common are UTIs in women than men?
Ten times more common due to shorter urethras
Most common type of health care associated infection
UTI due to cath
Community-acquired UTI is largely due to what
Colonization of the urinary tract by fecal flora by E. Coli
E. Coli found within what family
Enterobacteriacea
**Features of E. Coli
Gram (-) rod, Part of normal flora of colon, Ferments lactose (red on MCA), Oxidase (-)
Most common Gram negative rod associated with sepsis
E. Coli
What is the most common cause of community acquired UTIs and what is its reservoir?
E. Coli (80-95%), Reservoir = intestinal tract
Virulence Factors associated with E. Coli
Adhesins +Pili (binding), Hemolysin (lysis > inflammatory response), Endotoxin (inflammation)
Type I Pili
Attachment pili expressed by MOST E coli > bind to mannose residues on epithelial surfaces, Will be FLUSHED out with urine
Type P Pili
Expressed by UPEC of E. Coli > binds to sugars residues SPECIFICALLY on UROEPITHELIAL CELLS, Does NOT get flushed out with urine
2 Cause of UTI
Staphylococcus
**Features of Staphylococcus
Gram + clusters (cocci), Catalase +, Non-flagellate, motile or spore forming
**Two groups of Staphylococci and what they are differentiated by:
S. Aureus (coagulase +, Coagulase Negative Staph (Saprophyticus + Epidermis)
**Coagulase Negative Staph Saprophyticus Features:
Normal in GI tract, SECOND leading cause of UTIs, **NOVOBIOCIN RESISTANT (unlike Staph Epidermidis)
**Features and Prevalence of Proteus Mirabilis:
Gram negative enteric, high prevalence in chronically catheterized patients
Virulence Factor of Proteus:
Produces urease > breaks down urea in urine > creates alkaline environment
Implication of Alkaline Environment set up by Proteus:
Promotes precipitation of magnesium and calcium > formation of kidney stones
**Pseudomonoas Aeruginosa features:
Gram (-) rod, oxidase (+), Have pyocyanin/pyoveridin (blue/green pigment), Primarily a nosocomial +opportunistic infection
Pseudomonoas Aeruginosa UTI:
Primarily seen in patients with long-term indwelling urinary catheters or patients who have been treated with multiple courses of Abx
**Enterococcus features
G + cocci, catalase (-), (just like S Pneumoniae)
**How to differentiate Enterococcus from S. Pneumoniae:
Enterococcus tolerates high salt/bile and is NOT SENSITIVE to OPTOCHIN
Risk Factors for Enterococcus infection:
Treatment with broad spectrum Abx and catheterization
Asymptomatic Bacteriuria:
Significant bacteria on two successive cultures in asymptomatic patient Common in older men and women.
**Cases to treat asymptomatic Bacteriuria:
Pregnant women, prior to urologic surgery, after renal transplant
**Treatment for uncomplicated cystitis:
Trimethoprim/Sulfamethoxazole
**Treatment for Pyelonephritis
Fluoroquinolones for G (-), Amoxicillin for G (+)
Treatment for Asymptomatic Bacteriuria
No treatment, or in 3 cases– Amoxicillin, cephalexin or nitrofurantoin