Question book 4 Flashcards
73 year old with UTI
Why are they more common in elderly men?
urethral catheterisation normal-sized prostate increase of prostatic secretions dilation of ureter vesicoureteral reflux
urethral catheterisation - not that uncommon in men of this age to have a catheter. Usually for obstructive causes
prostate secretions decrease at this age. They are normally protective
Vesicoureteral reflux is common in children, not at this age
23 year old with UTI
what increases the risk of UTI?
use of spermicidal gel avoiding anal sex use of a condom consumption of cranberry juice post-coital micturition
use of spermicidal gel - disrupts normal flora
Other 3 factors reduce risk of UTI, cranberry juice has no evidence
55 year old presents with fever, no localising signs.
Urine culture has pure growth of an organism
Which bacteria are normally associated with haematogenous dissemination when found in mid-stream urine
Staph aureus Staph saprophyticus E. coli Salmonella Typhi Mycobacterium tuberculosis
Staph aureus - rare cause of primary UTI. So need to assess for bacteraemia spillover
E.coli/ Staph saprophyticus cause UTIs - but most likely ascending from outer urinary tract
Salmonella/ TB are rare in urine
22 year old presents with dysuria, frequency, urgency.
What is most common cause of community-acquired UTIs?
Klebsiella pneumoniae Staphylococcus saprophyticus E. coli Proteus mirabilis Enterococcus faecalis
E. coli - causes 70%-90% of infections
Klebsiella/ Proteus and Enterobacter are common causes, but mostly in relation to catheter associated UTIs
Enterococcus rarely causes UTIs
Staphylococcal UTI
How to discern if this is Staphylococcus aureus or Staphylococcus saprophyticus
Staphylococcus saprophyticus is:
- coagulase negative
- resistant to novobiocin
73 year old with UTI. Has long term catheter.
Which is true
- catheter associated UTI account for 40% of nosocomial infections
- bacteriuria is present in minority of patients with indwelling catheters at 30 days
- bacteriuria is frequently monomicrobial
- asymptomatic bacteriuria should always be treated
- patients with indwelling urinary catheters should receive antibiotic prophylaxis
catheter associated UTI account for 40% of nosocomial infections
- catheters become colonised quickly in most cases, so infections often polymicrobial. And asymptomatic cases should not be treated
- may be given antibiotics around time of insertion, but do not have an ongoing need for antibiotics
73 year old female with UTI
Why are UTIs more common in elderly women?
increased vaginal lactobacilli vesicoureteric reflux cognitive decline increased albumin in urine oestrogen replacement therapy
cognitive decline
risk factor itself due to poor hygiene
but also risk factor as delay in diagnosis - patient may be mildly confused, with bacteriuria, and unclear whether it needs treatment
23 year old pregnant woman has mid-stream urine submitted. how should it be interpreted?
asymptomatic bacteriuria develops 20-40% of women
asymptomatic bacteriuria is diagnosed with bacterial count higher than 1x10power5 CFU/ml
asymptomatic bacteriuria should always be treated in pregnancy
risk of pyelonephritis is comparable between pregnant and non-pregnant women
UTI in pregnancy have no effect on foetal development
asymptomatic bacteriuria is diagnosed with bacterial count higher than 1x10power5 CFU/ml.
Because vulvo-vaginal contamination can occur, recommended to send second urine sample before commencing treatment. Hence why we should not always treat asymptomatic bacteriuria in pregnancy
asymptomatic bacteriuria develops in about 10% of pregnant women, but higher risk of pyelonephritis developing in pregnancy
asymptomatic bacteriuria are more likely to have premature babies
23 year old symptomatic UTI, sample send shows sterile pyuria
Which condition is sterile pyuria not characteristic of?
renal tract Mycobacterium tuberculosis Chlamydia trachomatis urethritis antibiotic-treated E. coli UTI Neisseria gonorrhoea Staphylococcus saprophyticus UTI
Staphylococcus saprophyticus UTI would not be sterile as grows easily
Other organisms are fastidious, and difficult to grow
Also non-infectious causes of sterile pyuria e.g sarcoidosis, malignancy
54 year old with cirrhosis develops self-limtied diarrhoea after consuming raw oysters.
Two days later, presents with overwhelming sepsis, develops blistering skin lesions and dies.
What is most likely cause
Bacillus cereus Salmonella Heidelberg Salmonella Typhi Vibrio vulnifcus Cyclospora cayetanensis
Vibrio vulnifcus - causes enteritis, skin blistering or fulminant septicaemia.
Found in coastal waters, so ingestion of filter feeders causes contamination
35 year old male develops diarrhoea. He purchases two turtles illegally a week before symptom onset.
What is most likely pathogen?
Plesiomonas shigelloides Strongyloides stercocalis Salmonella typhi Salmonella Arizonae Vibrio cholerae
Salmonella enterica serotype Arizonae is associated with reptiles
23 year old male with diarrhoea.
Possible Plesiomonas shigelloides identified on blood culture
How is this differentiated from Shigella?
Shares some antigens with Shigella sonnei, so mis-diagnosis can occur due to cross-reacting antisera
Plesiomonas is oxidase pos
Shigella is oxidase neg
Associated with water or animal exposure
Children’s nursery has outbreak of diarrhoea.
10 children agred between 4 and 7 have become symptomatic in past 2 weeks with diarrhoea. Low volume, but with blood and mucus
What is most likely cause
Shigella spp Enterotoxigenic E. coli Giardia intestinalis Rotavirus Norovirus
Shigella
Shigella sonnei is most frequent shigella infection, and does not require treatment
Enterotoxigenic E.coli is common cause of travellers diarrhoea in places with lower hygiene standards. Less likely, but not impossible in our case
49 year old goes to nearby farm and eats pork chitterlings for lunch.
5 days later has diarrhoea (no blood or mucus) with abdominal pain and fever
What is most likely cause?
Shigella Enterotoxigenic E. coli Campylobacter coli Yersinia entercolitica Vibrio parahaemloyticus
Yersinia entercolitica
Can present with abdominal pain which may be mis-interpreted as appendicitis
Is a zoonosis
Campylobacter and E. coli do not usually have fever. Fever suggests significant systemic infection
Shigella would normally have bloody diarrhoea
Vibrio parahaemolyticus is related to sea-food
29 year old presents 33rd week of gestation with temp 38.8degC, with diarrhoea
Which organism is a particularly dangerous potential cause of this presentation?
Salmonella typhimurium Listeria monocytogenes Giardia intestinalis Taenia saginata Plesiomonas shigelloides
Listeria monocytogenes
Before 20 weeks associated with miscarriage. After 20 weeks associated with pre-term labour. If delivery occurs, risk of neonatal sepsis and meningitis
Identified with tumbling motility at room temperature (not 37degC)
