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Flashcards in Urinary tract infections Deck (56)
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1
Q

What is another name for urinary tract infections?

A

Acute cystitis

2
Q

How many women are affected by UTIs in their lifetime?

A

50%

3
Q

What causes UTIs?

A

Bacteria

Fungi

4
Q

What is pyelonephritis?

A

Infection of the kidneys

Following its spread from the bladder to the kidneys

5
Q

What is urosepsis?

A

Spread of the urinary tract infection to the blood

6
Q

Do UTIs happen more often in one gender?

A

Yes

Women are affected more often

Due to the anatomy of their bladders

7
Q

What percentage of nosocomial infections are UTIs?

A

40%

8
Q

What is the most common cause of UTIs?

A

Catherization

9
Q

Why are UTIs important?

A

High prevalence

High economic burden

High human impact

Antibiotic resistance

Management is suboptimal

10
Q

How many people are affected by UTIs worldwide?

A

150 million people

11
Q

How do UTIs have large human impacts?

A

Adds one extra bed day to hospital patients

12
Q

What percentage of E.coli are resistant to first-line antibiotics?

A

50%

13
Q

Common UTI pathogens

A

Gram negative bacilli like E. coli, Klebisella, P. aeruginosa

Gram positive cocci like S.aureus, enterococcus

Candida

14
Q

Uncommon UTI pathogens

A

Mycobacterium

Chlamydia trachomatis

15
Q

What is the most common pathogen causing UTI?

A

E. coli

16
Q

Which behaviours encourage bacteria to get into the bladder?

A

Sex

Horseback riding

Poor hygiene

17
Q

What are common symptoms of cystitis?

A

Dysuria

Frequency

Pain

Blood in urine

WBC in urine

18
Q

What are common symptoms in pyelonephritis?

A

Pain

Fever

Tachycardia

Nausea

19
Q

What are common symptoms in urosepsis?

A

Increased heart rate

Low blood pressure

Rapid breathing

Shivering

20
Q

What are common diagnostic tools for UTIs?

A

Dipstick analysis

Routine culture

Urinary microscopy

21
Q

What does dipstick analysis test for?

A

Leukocyte esterase

Nitrite

22
Q

What does routine culture test for?

A

Bacterial growth above 10^5 cfu ml-1

23
Q

What does urinary microscopy test for?

A

White blood cells in the urine, observed under microscopy

24
Q

What is the sensitivity of disptick?

A

46-66% in leukocyte esterase

6-18% in nitrite

25
Q

What is the sensitivity of urinary microscopy?

A

61-70%

26
Q

What are the disadvantages of dipstick analysis?

A

Misses infections

Only tests for leukocyte esterase, indicating the presence of leukocytes in the urine, and nitrites, indicative of gram negative bacteria

27
Q

What does the nitrite on dipstick tests rely on?

A

The bacteria must be able to reduce nitrate

Only gram negative bacteria are able to do this

28
Q

What are the advantages of dipstick analysis?

A

Quick

Cheap

29
Q

What is the disadvantage of routine cultures to diagnose UTIs?

A

Guidelines show diagnostic cutoff at 100 000 colony-forming units of bacteria per ml of urine

UTIs may be present at lower numbers

Also discarded if more than one bacteria grow

30
Q

What percentage of UTIs are recurrent?

A

25%

31
Q

What are the three types of UTIs?

A

Acute

Recurrent acute

Chronic

32
Q

What are the characteristics of chronic UTIs?

A

Lower urinary tract symptoms

Overactive bladders

Usually test negative for UTI

Pyuria

33
Q

What is the treatment of chronic UTIs?

A

Requires long-term antibiotic treatments with various side-effects

34
Q

What is LUTS?

A

Subacute UTI infections that don’t reach the diagnostic cutoff for UTIs

35
Q

What is the relationship between UTIs and urinary incontinence?

A

There is a theory that UTIs are related to urinary incontinence, a condition that affects 1.5-22% of the population

36
Q

What is the significance of the relationship between UTIs and urinary incontinence?

A

If a small proportion of patients has a bacteria-treatable-aetiology, their care could be transformed

37
Q

What antibiotics are E. coli resistant to?

A

Third generation cephalosporins

Fluoroquinolones

38
Q

What treatments are UTI sufferers relying on?

A

Carbapenems

39
Q

Describe the urothelium

A

Highly specialised tissue

Highly stratified morphology

Slow turnover - 200 days to shed completely

40
Q

What is the name of the cells making up the apical layer of the urothelium?

A

The umbrella cells

41
Q

Which mechanism is used to turnover the urothelium?

A

Conveyer-belt-like mechanism

42
Q

Describe how the urothelium turns itself over

A

The progenitor cells on the basal side of the urothelium makes new epithelial cells which replace the cells on the apical membrane

In a conveyer-belt-like mechanism

43
Q

How do bacteria use the urothelium to evade immune attack?

A

Attach and invade the urothelium by going inside umbrella cells

The umbrella cells die following invasion, leaving gaps in the urothelium

Bacteria enter through these gaps to form pods or long-term reservoirs

44
Q

How do bacteria form colonies?

A

Pods

Long-term reservoirs

45
Q

What shape are bacteria in reservoirs?

A

Spherical

46
Q

What happen to bacteria when they escape their reservoirs?

A

Change from spherical to normal rod-shape

Regain motility

Form longer filaments

47
Q

List the hypotheses trying to explain the reason behind recurrent infections present in UTIs

A

Vaginal commensal dysbiosis

Genetic risks

Covert pathogens

48
Q

Describe bacterial pods

A

Inside cells, bacteria divide to form huge colonies called pods

Bacteria change from rod-shaped to spherical to accommodate for the tight packing

Pushing of the epithelium leads to the formation of pods that explode to cause recurrent infection

49
Q

What are the benefits of pods for bacteria?

A

Allows them to evade immunity and antibiotics

50
Q

How do pods cause recurrent infection?

A

Pushing of the epithelium leads to the formation of pods that explode to cause recurrent infection

51
Q

Example of an innate immune response by the urothelium to infection

A

Shedding of the umbrella cells

52
Q

How can shedding of the urothelium cause issues

A

Allows small numbers of bacteria to invade into the deeper layers of the urothelium

Forms reservoirs that evade host degenses

They form intracellular pods by infecting and multiplying inside cells

53
Q

Can bacterial pods form in immature cells?

A

No

54
Q

How does filamentation act as an immune evading mechanism?

A

Tic tac shaped E. coli form longer filaments

These stick to the bladder, which allows bacteria to resist high tensile forces from the urine flow

Also, leukocytes cannot detect these filaments, so they allow the bacteria to evade immunity

55
Q

Describe future research areas in UTI

A

Use other uropathogens

Models based on humans

Increase the understanding of the mechanisms behind UTI recurrences

Understand the role of commensal bacteria

Better antibiotic treatment

56
Q

Explain the concept of covert pathogens

A

UTIs can be driven by short-lived but powerful urinary tract exposures to vaginal bacteria that are themselves not uropathogenic in the classic sense

= G. vaginalis