Microbiology 10 - UTIs

Question 1

What does it mean if squamous epithelium cells are found in an MSU sample?

Answer 1

The sample is CONTAMINATED

Question 2

What is an uncomplicated UTI?

Answer 2

Infection in a structurally and neurologically normal urinary tract

Question 3

What groups of patients are considered as having complicated UTIs?

Answer 3

male
pregnant
indwelling catheters/ hospital setting

Question 4

most common cause of UTI

Answer 4

E.coli

Question 5

2nd most common cause of UTI in YOUNG WOMEN

Answer 5

Staphylococcus saprophyticus

Question 6

which uTI associated with stones?

Answer 6

Proteus mirabilis

Question 7

Which UTI associated with prostheses e.g. indwelling catheter?

Answer 7

Staphylococcus epidermidi

Question 8

extra renal causes of urinary tract obstruction

Answer 8

BPH

Calculi

Question 9

intrarenal causes of urinary tract obstruction

Answer 9

PKD
SCD
Nephrocalcinosis

Question 10

haematogenous route of UTI - what tends to cause this and why do we worry?

Answer 10

S.aureus bacteraemia or infective endocarditis

s.aureus does not have appropriate virulence factors to cause ascending infection so if you see it in urine, likely that there is a deeper problem

Question 11

UTI sx in older patients

Answer 11

They tend to be asymptomatic

Question 12

standard ix for lower UTI

Answer 12

Urine dip + urine MSU for MC&S

Question 13

LEUCOcyte esterase -ve nitrite +ve outcome = ?

Answer 13

ABx; further management guided by urine culture

Question 14

leucocyte esterase +ve nitrite -ve outcome = ?

Answer 14

only start abx if clinical evidence of UTI

Question 15

if there are lots of nitrites in urine sample, what is this suggestive of?

Answer 15

E.coli infection

Question 16

what could be a cause of nitrite -ve leucocyte +ve UTI?

Answer 16

UTI caused by a non-coliform i.e. not E.coli

Question 17

would you do a urine dipstick in patients >65?

Answer 17

NO, it is not reliable as asymptomatic bacteriuria v common. First rule out sepsis! If UTI still seems likely –> culture

Question 18

what culture result is diagnostic of UTI?

^exception to this rule?

Answer 18

CULTURE of single organisms >10^5 CFUs/mL + urinary symptoms = diagnostic of UTI

E.coli or saprophyticus, cut off is >10^3 CFUs/mL

Question 19

what could be a cause of sterile pyuria? (Raised WCC but no growth on culture)

Answer 19

prior treatment with antibiotics (most common)
catheterisation
TB (not grown on normal culture)
STI

Question 20

what agar is the culture done on for UTIs?

Answer 20

Chromogenic agar

Question 21

uncomplicsated lower UTI in females - treatment + duration?

Answer 21

Nitrofurantoin/Cefalexin for 3 days

Question 22

In whom would you consider a 7 day abx course for uncomplicated lower UTI ? list 3

Answer 22

Men
Previous UTI with resistant organism
>7 days of symptoms

Question 23

Tx of pyelo once you have the culture results

Answer 23

IV coamoxiclav +/- gentamicin

Question 24

Candida UTI - Main cause?

Answer 24

Indwelling catheter

Question 25

mx of candiduria + catheter

Answer 25

removal of catheter may result in cure (fluconazole is no more effective)

Question 26

complications of pyelonephritis

Answer 26

perinephric abscess
chronic peel –> scarring + renal impairment
septic shock
acute papillary necrosis