Genitourinary infections Flashcards
(44 cards)
What are most common organisms causing UTIs?
E. coli 70% Klebsiella Proteus Enterobacter spp Enterococcus faecalis
Which patients require imagining of urinary tract, if pyelonephritis suspected?
All male patients
Females if >2 episodes of pyelonephritis
any patient with Proteus species isolated
Patient on CAPD for chronic renal failure. Last 24 hours noted dialysis fluid is cloudy, with mild abdominal pain.
What is most likely cause of this infection?
Staph aureus/ CoNS - 50% infections
gram neg including pseduomonas
fungi (candida) 5% - particularly if culture results are negative
Patient on CAPD for chronic renal failure. Last 24 hours noted dialysis fluid is cloudy, with mild abdominal pain.
Fluid sent for analysis
What criteria are used to confirm microbiological diagnosis of infection?
Cell count >100mm3, usually >50% polymorphs
fluid also grown in blood culture bottles
Patient on CAPD for chronic renal failure. Last 24 hours noted dialysis fluid is cloudy, with mild abdominal pain.
What is empirical treatment?
Intraperitoneal vancomycin and gentamicin
Patient on CAPD for chronic renal failure. Last 24 hours noted dialysis fluid is cloudy, with mild abdominal pain.
Pseudomonas isolated.
Patient on vancomycin and gentamicin.
Does organism alter antibiotic management?
Can stop vancomycin
Once improved, switch to ciprofloxacin for 21 days total treatment
Need to exchange PD line, as pseudomonas forms biofilms
Renal transplant patient has rising creatinine, concerns about rejection.
Urine microscopy shows “decoy cells”
What does this mean?
Decoy cells are infected epithelial cells, which have large, abnormal nuclei. Can sometimes look like cancer cells
In this case, like due to BK virus
What is usual natural history of BK virus infection?
50% of children infected by age 4 - most asymptomatic
80% of adults infected
transmitted respiratory, faecal-oral, sexual, transplant
remains latent in renal tubular epithelial cells. First sigsn of re-activation include slowly rising creatinine
What are symptoms of BK virus reactivation in immunosuppressed/ renal transplant patients?
Tubule-interstitial nephritis
haemorrhagic cystitis
pneumonitis
meningoencephalitis
How to diagnose BK reactivation
renal biopsy gold standard
BK virus DNA PCR - blood or urine
BK virus decoy cell microscopy - can be useful as screening tool
19 year old with fever, flank pain.
Urinalysis showed >50 white cells, 10 red cells, 3+ bacteria
gram negative rod seen, which is beta haemolytic
What is significance of WCC?
normal urine <10 white cells
> 50 suggests infection/ inflammation
bacteria colonies help point towards infection
19 year old with fever, flank pain.
Urinalysis showed >50 white cells, 10 red cells, 3+ bacteria
gram negative rod seen, which is beta haemolytic
What is causative organism?
E. coli can often be beta haemolytic
Pseudomonas is only other GNEG which is beta-haemolytic. But this would be less likely as young, and no catheter
Can differentiate between these, as E. coli will be lactose fermenter, and Pseudomonas will not
19 year old with fever, flank pain.
Urinalysis showed >50 white cells, 10 red cells, 3+ bacteria
E. coli in culture
Had amoxicillin with GP, which she failed to complete.
What is explanation for deteriorating?
Amoxicillin selected for resistance organism e.g E. coli
This pressure likely caused move of antimicrobial resistance plasmid ESBL
This provides resistance to penicillin and cephalosporins
What are treatment options for ESBL UTI?
Meropenem IV
Nitrofurantoin/ fosfomycin oral
Need to check sensitivities, as can be sensitive to other agents e.g tazocin, co-trimoaxozle, cipro, get
ESBL provides resistance to penicillin/ cephalosporins, but often confers resistance to multiple other antibiotics
What are features which indicate pyelonephritis over cystitis?
Cysitis - bladder
Pyelonephritis - kidney
Systemic symptoms - fever flank pain hypotension tachycardia
urinalysis - white blood cell casts
Why is it important to differentiate cystitis from pyelonephritis?
cystitis treatment duration is 3 days female, 7 days male
pyelonephritis is 7-14 days treatment
pyelonephritis will require imaging to assess for renal stone obstruction
What are virulence factors, which allow E. coli to infect urinary tract?
P fimbriae - adhesion, and resistance to phagocytosis
haemolysin - directly cytotoxic
aerobactin - siderophore which is molecule which scavenge iron, an essential nutrient for bacteria
What are reasons that a gonococcal vaccine cannot be produced?
Vaccines normally target exotoxins or cell surface component
Gonorrhoea does not produce conventional exotoxin
Gonorrhoea can re-arrange pilin genes, called antigenic variation. Which changes the pili expressed on surface
Chlamydia used detected via NAAT
What media can be used for culture?
McCoy cells
fluorescin stain can show intracellular chlamydia
What is life cycle of chlamydia?
infectious elementary body is endocytosed
bacteria develop into reticulate bodies, which are reproductive form
reticulate bodies then reproduce, and condense to form elementary bodies, which are released when cell lyses
What infections do different serovars of chlamydia trachomatis cause?
Chlamydia trachomatis A/ B/ C - trachoma
Chlamydia trachomatis D-K - genital chlamydia
Chlamydia trachomatis L1 -L 3 - LVG
Chlamydia psitacci - pneumonia
Chlamydia pneumoniae - pneumonia
16 years old presents with crampy abdo pain, vaginal bleeding, abnormal discharge.
Considering PID
Swabs for chlamydia/ gonorrhoea NAAT are negative.
Why does treatment still need to cover for these organisms?
Swabs are often endocervical, so cannot exclude upper genital infection e.g ovaries/ fallopian tubes
What are differential diagnoses for ulcerating genital lesions?
Painful -
HSV
LVG
Chancroid
Painless
Syphilis
Donovanosis
HSV2 is usual culprit of encephalitis
Why are cases of HSV1 encephalitis rising?
Unclear
Possibly higher rates of oral sex, leading to higher HSV1 transmission
Primary HSV1 genital infection may then lead to encephalitis
