Microbiological diagnosis of urinary tract infection

Question 1

Hvilke bektrakninger bør allmennlegen ha i mente ved diagnostisering av mikroorganismer ved urinveisinfeksjoner (UVI)?

Answer 1

Question 2

Hvilke mikroorganismer er det som fører til UVI´er?

Answer 2

Uncomplicated UTI: E. coli and Staphylococcus saprophyticus Complicated UTI: E. coli and more others (gram neg rod). NOT S. saprophyticus.

https://pubmed.ncbi.nlm.nih.gov/25853778/

Question 3

Gi en forenklet oversikt over hvilke mikroorganismer som gir UVI´er?

Ukompliserte og kompliserte

Answer 3

Question 4

Hvordan er bakteriologien ved ukomplisert UVI i Norge?

Answer 4

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181106/

Question 5

Hva mener man med komplisert/ukomplisert UVI, og øvre/nedre UVI?

Answer 5

Question 6

Hva viser bildet til?

Answer 6

This table shows the likelyhood of that the bacteria found in a mid stream urine is the cause of the UTI. As you can see the likelyhood is high for E. coli , even in low concentrations. If you find Enterococci or GBS however, the likelyhood of it being the cause of the UTI is low even in high concentrations. This study compared detections in a midstream urine to that in urine sample taken by a catheter. The tables shows that the likelyhood of finding E. coli in the catheter sample is high if it is present in the midstream urine. But for enterococci and GBS the bacteria are usually only found in the midstream urine.

https://www.nejm.org/doi/full/10.1056/nejmoa1302186

Question 7

Hvilke virulensfaktorer har UPEC?

Answer 7

https://pubmed.ncbi.nlm.nih.gov/25853778/

Question 8

Hva er kateter assosiert med når det kommer til UVI?

UPEC

Answer 8

How many urinary catheters are colonised.

https://www.researchgate.net/figure/Formation-of-a-biofilm-Planktonic-cells-attach-first-reversibly-to-the-surface-and-then_fig2_281922206

Question 9

Når bør det tas en urinkultur ved UVI?

Answer 9

Question 10

Hvordan bør urinprøven til bakteriedyrkning tas?

Ikke kateter

Answer 10

https://www.bioingenioren.no/fag/fag-i-praksis/eldre-artikler/fagartikkel-riktig-provetaking-er-viktig—ogsa-for-urinprover/

https://bmcprimcare.biomedcentral.com/articles/10.1186/s12875-016-0465-4

Question 11

Hvordan bør man ta urinprøver til dyrkning hos pas. med permanent kateter?

Answer 11

The catheter should be closed for 2 hours. Then you release some urine into the hose, then close the catheter, and let that urine into the bag (that is the urine that has been in the hose and not the bladder). Then you can open the catheter again, and take a sample from the urine that comes. Interpretation of urine samples is based on the assumption that the urine has been in the bladder for 2 hours. The drainage port end has a sampling port where you can push a syringe without a needle in for sample collection.

Question 12

Hvilke andre metoder kan man bruke for å få urin til bakteriedyrkning?

Answer 12

Question 13

Hvordan skal man sende urinprøver til laben?

Answer 13

Question 14

Hva er “Dipstick agar”?

“Uricult” på kontoret

Answer 14

Question 15

Hva viser bildene?

Answer 15

Urindyppekultur: Red: MacConkey agar, White: E. coli agar, Cled: Both gram negative and gram positive bacteria Problems: difficult to distinguish 10^3 from lower number (insignificant growth), difficult to see mixed culture.

Question 16

Kan man stole på urinstiks ved UVI?

Answer 16

https://sykepleien.no/en/forskning/2017/01/can-we-trust-urine-dipsticks

Question 17

Hva er gullstandarden for urinprøver i laben? Hvordan utfører man dette?
Hvilken annen teknikk er og nyttig?

Answer 17

Flow cytometry count bacterial cells. Not as precise as culture and do not identify the bacteria. But a negative flow cytometry result means that the sample does not need to be cultured and you get a negative result much faster. This is as fast a urine culture grows due to the need of allowing bacteria to grow.

Question 18

Hva er en kvantitativ urinkultur?

Answer 18

This is very imperfect. But currently the best we have.

Question 19

Hvordan setter man “cut-off” for bakteriell vekst i en urinkultur?

Answer 19

One try to find an apporpriate balance between adequate sensitivity and specificity. Keep in mind that these numbers are only for E. coli.

https://www.nejm.org/doi/full/10.1056/nejmoa1302186

Question 20

Hva er foreslåtte nedre grense for bakteriekonsentrasjonen ved urinprøver?

Answer 20

So these are the recommonded quantities of bacteria in urine required for considering the results as possibly significant. As you can see, a midstream urine require the growth of 10^3 or more. Also note, that for this to be true, the patient must have symptoms of UTI! More bacteria are required if the the sample method is different, such as an indweling catheter, if the bacteria are doubtful pathogens or if there is more than one species in the urine.

https://www.fhi.no/globalassets/dokumenterfiler/rapporter/strategirapporter/strategirapport-nr-21-2007-bakteriologisk-diagnostikk-ved-urinveisinfeksjon.pdf

Question 21

Hvordan identifiserer man bakterien ved en UVI?

Answer 21

Chromogenic: so different bacteria may have different colours. We use an agar (UTS) where E. coli usually becomes red and Staphylococcus saprophyticus usually becomes pink. We also use a blood agar because sometimes (rarely) the bacteria dont grow well on the chromogenic agar. When there is growth on the agar we often only do biochemical tests in addition to the colour on the chromogneic agar or other morphological features (Indol + for E. coli, Esculin and telur for E. faecalis). Sometimes we must use MaldiTof to be sure of the ID.

Question 22

Hvilke patogene bakterier er vanlige ved UVI?

Answer 22

E. coli is most common. S. saprophyticus is a fairly common primary pathogen (and is seen in uncomplicated UTI). Other gram negative rods and Enterococci are fairly common as secondary pathogens (and are seen in complicated UTI).

Question 23

Hva er tolkningen av urinkulturen avhengig av?

Answer 23

Question 24

Hvordan tester man en urinkulturs sensitivitet til antimikrobielle midler?

Answer 24

Question 25

Hvilke antimikrobielle midler er E.coli sensitiv for?

Answer 25

Question 26

Hva mener man med asymptomatisk bakteriuri?
Hvilke er nasjonale anbefalninger i Norge?

Answer 26

Question 27

Hvilke andre analysemetoder brukes på urinprøver?

Answer 27

Question 28

Gi en oppsummering når det kommer til mikrobiologisk diagnostikk ved UVI

Answer 28

Question 29

Hva bør man gjøre hos denne pasienten?

Answer 29

Question 30

Hva bør man gjøre hos denne pasienten?

Answer 30

Question 31

Hva bør man gjøre hos denne pasienten?

Answer 31

Question 32

Hva bør man gjøre hos denne pasienten?

Answer 32

Question 33

Hva bør man gjøre hos denne pasienten?

Answer 33