UTI Flashcards
Ureters are
tubes that carry urine from kidneys to bladder
-sealed by ureterovesical valves
Bladder is
-used a storage for urine
urethra
tube that passes from bladder to outside of body
What are the natural defenses to infection in urinary tract
-urine naturally has salt, urea, ammnonia + acidic pH
-lysozymes to degrade peptidoglycan and kill gram pos
-unidirectional flow to wash away bacteria that try to stick to epithelial cells
-epithelial cells have mucous, cytokines and antimicrobial agents
What are the natural defenses in men to prevent UTI
secretion for prostate contains zinc
-longer urethra
-scrotum is a barrier between anus and urethral opening
What are the natural defenses in women to prevent UTI
-Lactobacilli use h2o2 and lactic acid for a more acidic pH
-growth and attachment to epithelial cells in inhibited
Ascending route of infection
Ascending
-organism travels from urethra to bladder , common in women
-fecal flora can move up peri urethral area can get into kidneys or bloodstream to cause septicemia
occurs from
improper wiping
sex
catheterization
renal stones
shorter distance from perianal to urethra in women
descending or Hematogenous route of infection
-from blood to kidney
-bacteria from infection gets into the bloodstream and seeds the kidney
-not common <5%
-due to invasive bacteria like Salmonella, S aureus, TB, Listeria , Leptospira
-renal calculi in ureters
Symptomatic bacteriuria
-lots of organisms in urine
-UTI symptoms
-positive for leukocyte esterase and nitrate
-treat with ABtics
Asymptomatic bacteria
-presence of bacteria in urine NO symptoms
-elderly women, after sex, if there is incomplete voiding
-not treated with AB
-treatment only if pregnant, kidney transplant , immunocompromised, child with Vesicoureteral reflux
Urethritis
-infection of urethra
-associated with STI
-caused by any pathogen or N. gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis
-trauma from sex, chemical irritation
symptoms - dysuria, pus discharge
Cystitis
bladder infection
-in both men and women after catheterization
-most common type in women
-due to sex or improper wiping
-can move to kidney or become systemic if untreated
-E coli most common cause
Symptoms - dysuria , frequency , hematuria
Pyelonephritis
Kidney infection
-by a ascending route or hematogenous
-see lots of bacteria in urine
-most serious UTI because it can cause kidney damage or become systemic to cause sepsis
symptoms : fever, lower back pain, dysuria, frequency/urgency
prostatitis
-backward flow of urine into prostate
-or from surgery
Acute - men <35 fast comes and goes
Chronic 40-70 men , starts slow but lasts
-chronic can also be non bacterial
-known as pelvic pain of unknown origin
-can be caused by autoimmune response, previous viral infection or nerve damage
symptoms - fever, swollen prostate, back pain, dysuria, frequency/urgency you cant void completely
Virulence factors
flagella
swarming
fimbriae/pili
casule
biofilm
production of toxins
flagella - allows bacteria move up the urinary tract
swarming proteus - super motility occuring with an infection because of catheterization
fimbriae/pili - helps bacteria with cell attachment
capsule- helps with attachment and shields against AB/toxins
Biofilm: helps with attachment and evasion of toxins/AB
production of toxins- enzymes that destroy RBC, WBC, epithelial cells
What are biofilms used for
extracellular matric made of polysaccharide
-allows bacteria to attach to body surface, indwelling devices or water pipes
-protects against immune system
-3 stages attachment, maturation, dispersion
-can be made up of more than 1 bacteria CO BIOFILMS
Ps. aeruginosa + B. cepacia = lung infections with cystic fibrosis
-cell signalling (quorum sensing) is used by the bacteria in the biofilm
-easy for gene exchange (conjugation/plasmids)
-bacteria in biofilm have a different gene makeup then those that are freely suspended
-when nutrients are scarce thats the signal to dettach
Contributes to: necrotizing fasciitis, osteomyelitis, stones, catheters, vascular grafts, IUD colonization & infection.
types of host responses
Urinary Tract Epithelial Cells
-secrete cytokines to recruit phagocytes
-removal of growth factors from urine to prevent bacterial growth
-mucin secretion to prevent bacteria from adhering to cells
-lysosome production
-exocytosis of malfunctioning lysosome
how does the host use the innate system to respond to infection
-initiation of proinflammatory response to exfoliate top layer of infected epithelial cells
-exposed bacteria is washed away by increasing flow of urine
-signals neuts and NK to phagocytose bacteria
-mast cells are released to balance inflammatory response
What is the adaptive host response in a host to a UTI
- reponse in bladder is limited
-if infection is only in the bladder the body fails to induce an AB response which is why there is a high rate of UTIs after a bladder infection
-infections in kidneys can cause AB production
STRUCTUAL FACTORS THAT MAY RESULT IN UTI
Obstruction of urinary tract:
prostatic enlargement, urethral strictures, stones, tumour, bladder diverticula
STRUCTUAL FACTORS THAT MAY RESULT IN UTI
Incomplete bladder emptying
neurological damage due to stroke; spinal cord injuries, chronic prostatitis, kidney stones
STRUCTUAL FACTORS THAT MAY RESULT IN UTI
Instrumentation:
catheters can lead to nosocomial infections of urinary tract.
STRUCTUAL FACTORS THAT MAY RESULT IN UTI
Vesicoureteral reflux
-mostly in children
-the valves that prevent reflux of urine back into ureter dont work or the doensnt travel far enough into the wall
-recurrent UTI
why are children at risk of UTI
-infant boys have more bacteria in bladder urine because of structural abnormalities
-circumcision protects from male infant UTI
-infant UTI presents as FUO
-preschool girls have more UTIs than boys = inappropriate wiping
