Urinary Tract Infections Flashcards by Morgana Ramsey

What is cystitis? and what are the symptoms?

Bladder infection.
Symptoms include:
- Dysuria (painful urination)
- Frequency and urgency of urination
- Suprapubic pain

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What is pyelonephritis and what are the symptoms associated?

Kidney infection

- Cystitis symptoms plus: Flank (over kidney area) pain, back ache, fever, rigors (shaking, chills)

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What does the presence of large numbers of epithelial cells in a urine specimen indicate?

Indicates that the sample is badly collected, possibly an FVU

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What type of organisms would you expect to be present in an FVU? (list 4 types)

Normal flora:

CONS (Coagulase Negative Staphylococcus)
Corynebacteria (GPB)
Lactobacilli (GPB)
Enterobacteriaceae (from GIT/rectum)

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How many colonies would you equate to >10^8 cfu/L using the calibrated loop method of determining bacterial numbers?

> 200 colonies

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List two methods used in clinical labs to determine a urine colony count.

Filter paper foot

- Calibrated loop

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List two parasites (genus and species) that might be detected in urine?

Schistosoma haematobium

- Trichomonas vaginalis

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What does the presence of yeast in urine usually indicate?

in high number it means a yeast infection (thrush)

- usually it means a genital infection or a poorly collected specimen

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What does the presence of uric acid crystals in urine usually indicate?

Possibly Leukaemia or lymphoma

- 16% of urine with uric acid crystals may be due to gout.

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What does the presence of calcium oxalate crystals in urine usually indicate?

possibly due to kidney stone

- can be seen in normal urines as well

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What urine WCC would normally be associated with a UTI?

> 100 x 10^6 WBC/L is consistent with a UTI

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What does the presence of nitrites in a urine sample indicate?

bacterial infection in the urinary tract which could lead to a UTI

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What does the presence of nitrites in a urine sample indicate?

Indicates the presence of bacteria (Enterobacteriaceae) which reduces nitrates to nitrites

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If there were 7 PMN cells in one square mm of a disposable counting chamber from a urine sample, how many WBC would there be in 1L? (express your answer using scientific notation x10^6 WBC/L)

Count = ~7 WBC in 1mm squared
7 x 10 = 70 WBC in 1mm squared (1 microlitre)
70  x 1000 = 70000 WBC in 1mL
70000 x 1000 = 70 x 10^6 WBC per Litre
Reported as: <100 x 10^6 WBC per Litre

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True or false: UTI’s are one of the most common infections investigated in the clinical microbiology lab.

True

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What is a UTI?

A UTI is an invasion of any tissues of the urinary tract extending from the renal cortex to the urethral opening

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Are UTI’s more common in males or females?

Females by 30:1

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What is Urethritis?

An inflammation of the urethra

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What is Glomerular nephritis (GMN)?

An inflammation of the glomeruli

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What can cause Glomerular Nephritis?

A variety of causes which can include:

Post bacterial infection
cancer of the lungs or bowel
IgA nephropathy

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True or False: other than the distal urethra all other areas of the urinary system should be sterile.

True

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What is the most common organism isolated from community acquired UTI’s in WA?

Escherichia coli (75%)

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What is Urethritis?

An inflammation of the urethra

what are the different types of specimens collected for UTI testing?

MSU
Supra pubic aspirates
Catheter specimens
Nephrostomy sample (via tube inserted into kidneys)
Paediatric bags

If there will be a delay in processing the urine sample, at what temperature does the sample need to be stored at?

4 deg C

When examining Urine Specimens what lab procedures are conducted for ALL samples?

- Macroscopic examinations - Dipstrip/Dipstick test - Urine colony count - Microscopic examination (wet prep)

When examining Urine Specimens what lab procedures are conducted for samples with significant WBC or RBC present?

Full culture

For a full culture of a urine sample what is being looked at/tested?

- Isolating organisms that can be ID with rapid tests - Biochemical reactions (Microgen, API) - Antibiotic susceptibility

For macroscopic examinations of urine samples list the possible effects and what they may indicate.

- Clear = Normal - Cloudy/turbid = possible infection - Green = diet or drugs - Blood in urine = Haematuria or menstruation

What does the presence of increased protein found in a sample mean?

can indicate kidney damage or presence of organisms in the urine.

What is the normal pH range for urine and how can this be effected?

pH in urine is normally 6 but can be affected by diet and sometimes bacteria

What does the presence of blood in urine indicate?

Can indicate kidney/Urinary Tract damage, or menstrual blood contamination.

What does the presence of glucose in urine indicate?

indication of diabetes or pre-diabetes.

Urine colony counts are performed on all urine specimens. What are the two culture media used and what do they help determine?

MAC or CLED agar. These help to determine lactose fermenting bacteria which helps to ID the bacteria.

When performing a streaking out for urine colonies how is the calibrated loop used to streak out the culture plate?

1. dip into urine sample 2. touch the loop to the culture plate, creating a line down the centre of the plate. 3. Using the same loop (without flaming or re-dipping) draw the loop across the entire plate in a zig-zag fashion, crossing the centre line numerous times.

What does CLED stand for? How does it work?

Cysteine Lactose Electrolyte Deficient agar. - Electrolyte deficiency prevents swarming by Proteus sp. - Differential for lactose fermenting pathogens. - Lactose fermenters turn the plate yellow, Non-Lactose Fermenters keep the plate blue/green

Using the Calibrated Loop method for colony count, How do we calculate the CFU per ml of urine if there were exactly 200 colonies growing from 2 micro litres of urine?

200 bacteria x 500 (multiplication factor) = 100,000 bacteria per 1 ml (1000 micro litres) of urine This is the same as 1 x 10^5 cfu/L or 10^5 cfu/L

What is the significance of >200 colonies equal to?

>10^5 orgs/ml (same as >10^8 orgs/L)

What is the significance of 20 - 200 colonies equal to?

10^4 - 10^5 orgs/ml

What is the significance of 0 - 20 colonies equal to?

<10^4 orgs/ml

How do you calculate the indices when going from ml to L?

add the indices together

How do you calculate the indices when going from L to ml?

subtract the indices by 3

A pure colony count of >10^8 orgs/L AND a WCC of >100 x 10^6 WBC/L indicates what?

UTI

<10^7 cfu/L (which is equal to <10^4 per ml) indicates what?

Normal urine

A pure colony count of 10^7-10^8 orgs/L AND a WCC of >100 x 10^6 WBC/L indicates what?

Possible UTI

What type of WBC would indicate a UTI?

Neutrophils (PMN)

In a Wet Preparation if you were to see WBC or RBC under the microscope, what would this indicate?

WBC - usually associated with infection | RBC = may or may not be associated with infection

In a Wet Preparation what are casts indicative of?

``` acellular = possible dehydration cellular = pyelonephritis (WBC) or GMN, glomerular damage if RBC as well. ```

What does the presence of Tyrosine crystals indicate?

Possible liver damage

How are WCC reported if there are less than 100 in the counting chamber?

the actual number of what was counted is reported | e.g. 30 x 10^6 WBC/L

How are WCC reported if there are greater than 100 in the counting chamber?

>100 x 10^6 WBC/L

Other than microbes in the urine specimen, what other elements may be viewed in a wet prep?

- spermatozoa | - artefacts (i.e. cotton fibres)

In a wet preparation, if >10 x 10^6/L WBC are counted this is considered significant, what other testing does the sample require?

- Direct sensitivity plate on Sensitest or MHA | - Purity plate on BA or similar

How can the identity of a pathogen causing a UTI be determined?

- Colony morphology - Gram stain - Catalase test - Oxidase test - Motility - Spot indole - API20E or MALDI-TOF (if required)

If a GPC is identified in the Gram stain how do we proceed with identification of Genera and species?

By following the flow diagram in the lab manual | e.g. catalase/oxidase testing

If a GNB/C are identified in the Gram stain how do we proceed with identification of Genera and species?

Begin using the systematics tables (Cowan and Steel) and then API or MALDI-TOF

What does the "E" stand for in the API 20E test strip?

Enterobacteriaceae