Lecture 8 Flashcards
likelihood of experiencing a UTI for women and men, and is secondary infection more likely after experiencing a UTI?
women = 40-50%
men = 10-12%
- yes, secondary infection is more probable
downfalls of antibiotic treatment for UTI’s
costly, disrupts normal flora, increased likelihood of drug resistance
what is the endpoint of treatment for UTI’s?
sterilisation of urine and loss of symptoms
Bacteria that is responsible for most community-acquired UTI’s, and most susceptible gender and age groups
A uropathogenic Escherichia coli (UPEC) called Proteus mirabilis is responsible for most CA-UTI's Young women (opening of the anus is close to the urethra) and old men (enlarged prostate --> pooling of liquid (stasis) allows bacteria to grow)
Bacteria that is responsible for most hospital-acquired UTI’s, and most susceptible gender and age groups, mode of transmission, are they more or less drug-resistant than CA-UTI’s?
UPEC and other bacteria (Proteus mirabilis)
non-gender specific
device-related transmission - urinary catheter
more drug-resistant
signs of a CA-UTI
bad smelling urine, cloudy urine, hematuria (blood in urine)
symptoms of a CA-UTI
frequent toilet breaks, dysuria (pain when urinating), cystitis (infection of the urinary system and bladder), pyelonephritis (kidney infection, causes fever), flank pain (kidney), hesitancy to urinate, urgency to urinate
diagnostics of UPEC E.coli
Gram-negative, rod, oxidase negative
CA-UPEC source of bacteria
Colon (colonise there)
CA-UPEC infection route of transmission
Ascending route off infection (colon –> urethra –> bladder (cystitis) –> ureter (pyelonephritis) –> kidney)
risk factors for CA-UPEC infection
sex (women), sexual activity women (20-40), previous UTI’s, antibiotics that disrupt vaginal flora, underlying disease that leads to stasis
virulence factors of Proteus mirabilis colonisation
siderophore (iron uptake), pili (attachment to bladder, type 1 fimbriae bind to mannose residues, S-fimbriae (SFA-1), P-related fimbriae (prf), curli bind to amyloid, P-pili bind to globobiose in the membrane of kidney cells)
virulence factors of Proteus mirabilis immune evasion
flagella (motility), invades cells and colonises, escapes sick cells to infect others, form QIR (quiescent intracellular reservoirs)
toxin to cells by Proteus mirabilis
alpha-hemolysin (punctures membrane of RBC’s), cytotoxic necrotising factor (affects WBC’s)
progression of symptoms for CA-UTI Proteus mirabilis
frequency, urgency and dysuria problems, urine is smelly and cloudy - cystitis –> develops into pyelonephritis, mild fever (38degrees), pain in the suprapubic region (no higher than kidneys)
sample tested for identification of Proteus mirabilis
urine (mid-stream so there isn’t much skin bacteria, usually sterile but if it touches the walls then there will be some bacteria) analysis immediately or stored <4degrees
microscopy of urine in Px with CA-UTI
sediment, bacteria, WBC’s (neutrophils), epithelial cells (bladder sheds cells with bacteria on them) seen
type of culture used to diagnose UTI and CFU requirement for UTI
CLED agar: cysteine (requirement of UPEC), electrolyte-deficient (prevents swarming), lactose (UPEC causes blue –> yellow colour change due to change in pH)
10^5CFU/mL or 10^8CFU/L = infection
further tests to diagnose CA-UTI
MALDI-TOF (mass spectrometry for microorganisms), dipstick test: positive for nitrites (bacteria convert nitrates –> nitrites), positive for leukocyte esterase (presence of WBC’s, present in infections of the bladder)
treatment options for CA-UTI’s
fluids and pain relief, give advice to Px (hygiene, don’t hold on, go to the toilet, drink lots of fluids*, dietary changes (cranberry juice, mannose tablets (attaches to mannose so bacteria can’t), live yoghurt)
advice for antibiotic use for CA-UTI’s
advise fluid uptake, ensure antibiotic reaches kidneys and are excreted in urine, be aware of resistance issue and of persistent infections, if there is a reoccurrence it is better to change drugs to prevent resistance than to use the same drug (use non-penicillin antibiotics, e.g. trimethoprim or ciprofloxacin)
why and when no antibiotics should be used for UTI’s
increases resistance, if Px is a healthy young woman fluids and her immune system should be sufficient)
Px should return if symptoms persist or worsen (blood in urine, fever, flank/loin pain are signs of pyelonephritis)
why and when antibiotics should be used for UTI’s
If there is a clinically established infection (enumeration - 10^5CFU/mL - significant bacteriuria), UPEC infection
what disease is commonly seen for community-acquired and hospital-acquired UPEC infections?
Cystitis
