Urinary tract infection Flashcards
1
Q
definition of a urinary tract infection
A
the presence of micro-organisms in the urinary tract that are causing a clinical infection
2
Q
LOWER UTI
A
infection that is confined to the bladder (cystitis)
3
Q
UPPER UTI
A
infection involving the ureters +/- the kidneys (pyelonephritis)
4
Q
Urine in the kidneys, ureters and bladder is normally
A
sterile
5
Q
the distal urethra is
A
colonised by micro-organisms from the GI tract: coliforms and enterococcus
6
Q
complicated UTI
A
is a UTI complicated by either:
- systemic symptoms OR
- urinary structural abnormality/ stones
7
Q
bacteririuria
A
bacteria present in the urine but does NOT always means infection especially in elderly patients and those with catheters (must determine whether it is symptomatic in order to rule out a UTI)
8
Q
CYSTITIS
A
INFLAMMATION OF THE BLADDER WHICH AGAIN IS NOT ALWAYS CUASED BY INFECTION
9
Q
risk factors for UTI
A
- Female= have shorter and wider urethra
- sex
- pregnancy
- indwelling catheters
- abnormalities of the urinary tract
10
Q
2 routes of infection for a UTI
A
- ascending infection
- bacteraemia
11
Q
ascending infection
A
is the most common route of infection for a UTI, bacteria from the bowel colonises the peri-anal skin which spreads to the distal urethra and then spreads upwards
12
Q
bacteraemia
A
uncommon route of infection for UTIS, bacteraemia gets seeded in the kidneys resulting in the formation of multiple abscesses
13
Q
steps to ascending infection
A
- contamination of the peri-urethral skin with a uropathogen from the gut
- colonisation of the urethra and migration to the bladder
- colonisation and invasion of the bladder mediated by PILI and adhesions causing an inflammatory respsone in the bladder
- neutrophil infiltration
- bacterial multipiclation and immune system subversion
- biofilm formation
- epithelial damage by toxins and proteases
- Ascension to the kidneys
14
Q
Most common pathogen causing UTIS
A
Uropathogenic E.coli
15
Q
E.COLI is
A
gram negative air aerobic bacill (ie a coliform)
16
Q
4 SUB-TYPES OF E.COLI
A
- EHEC
- ETEC
- EIEC
- EPEC
17
Q
EHEC
A
- stands for entero-haemorrhagic E.coli which causes blood diarrhoea and is mostly caused by contaminated red meat
- Caused by serotype E.coli O157 which produces shiga like toxin (verotoxin) which damages endothelial cells which causes intra-vascular haemolysis (breakdown offered blood cells) which leads to platelet aggregation and fibrin strand deposition mainly in the renal vasculature
18
Q
classic triad in HAEMOLYTIC URAEMIC SYNDROME
A
- Microangiopathich haemolytic anaemia
- thrombocytopenia
- renal failure
19
Q
who does haemolytic anaemic syndrome mostly occur in
A
children
20
Q
symptoms of haemolytic uraemia syndrome
A
- bloody diarrhoea
- abdominal pain
- AKI
- haematuria/ proteinuria
21
Q
investigations of E.coli O157
A
stool toxin test, urinalysis and blood which show thrombocytopenia and increased creatinine
22
Q
ETEC
A
enterotoxigenic E.coli which is also known as travellers diarrhoea it causes a watery diarrhoea which has NO blood in it
- produces enterotoxin which adheres to intestinal mucosa but does not invade
23
Q
EIEC
A
invades intestinal mucosa CAUSING DYSENRY BUT DOES NOT PRODUCE A TOXIN
24
Q
EPEC
A
- common in children
- attaches the the epithelium causing loss of micro-villi causing a mucousy diarrhoea
25
proteus
gram negative aerobic bacilli which is large (i.e. coliforms)
26
struvite renal stones are
potentiated by bacterial infection which hydrolyse urea to ammonium which increases the urinary pH to neutral or alkaline values i.e. psuedomona, proteus, klebsiella
27
pseudomonas aerguinoas
gram negative strict aerobic bacilli
28
pseudomonas aerguinosa is more common in
patients with instrumentation and catheters
29
pseudomonas aerguinosa is resistant to
all orla antibiotics except oral ciprofloxain (one of the C. difficile antibiotics)
30
Ciprofloxacin
- inhibits bacterial DNA gyrase which prevents supercoiling of bacterial DNA
31
Ciprofloxacin should not be used in
pregnancy or young children
32
gram positive causes of UTIS
- enterococcus
- staphylococcus sacrophyticus
- staphylococcus aureus
33
enterococcus
gram positive cocci in chains which is gamma haemolytic and lives in the GI tract there are different types:
- enterococcus faecalus seen in UTIS
- enterococcus faecium
34
enteroccous causino a UTI is most common in
hospital acquired UTIS
35
staphylococcus sacrophyticus is
a type of coagulase negative staphylococcus which usually affects females of child bearing age
36
staphylococcus aureus causing UTI
is uncommon and is usually seen in bacteramiea cases
37
symptoms and signs of UTI
- dysuria
- frequency of urination
- nocturia
- haematuria
- fever
- loin pain
- rigors
38
loin pain rigors and fever are more
specific to pyelonephritis rather than cystitis
39
risk factors for cystitis
female, history of UTIS, sex, vagunal infection, diabetes, obesity, genetic susceptibility
40
symptoms of cystitis
dysuria, frequency, urgency, nocturia, haematuria, supra-pubic pain
41
risk factors for pyelonephritis
diabets, HIV/AIDS. iatrogenic immunosuppression, congenital or acquired urodynamic abnormalities
42
symptoms of pyelonephritis
back and or flank pain, fever, riggers, malaise, nausea, vomiting anorexia and the symptoms of cystitis
43
organisms cases CYSTITIS AND PYELONEPHRITIS
UPEC, KLEBSILLE, STAPH SACROPHYTICUS (CYSTITIS)< STAPH AUREUA (PYELONEPHRITIS), ENTEROCOCCUS FAECALUS, PROTEUS (PYELONEPHRITIS
44
specimen collection
- first urine passed likely to be contaminated with urethral colonisers so mid stream urine is used instead
- wash perineum with sterile saline first
45
container used for specimen
boron container contains boric acid which preserves urine for 24 hours, sterile universal container must reach lab within 2 hours
46
bag urine
used in babies but commonly contaminated with the bowel flora
47
what other specimens can be used
catheter specimen of urine or supra-pubic aspiration of urine
48
urinalysis
dipstick urine may indicate infection in selected patients
49
DO NOT DIPSTICK URINE OF
The elderly or people with catheters
50
leukocyte esterase
indicates the presence of leukocytes (white blood cells) in the urine
51
nitrites
nitrites indicate the presence of bacteria in the urine however some bacteria reduce the conversion of nitrates to nitrite so nitrites can be negative in enterococcus staphylococci and pseudomonas even though there is an infection present
52
urine microscopy
only used for selected cases and is not routinely carried out
53
Culture of urine
looks for signs of significant baceiruria using Kass criteria
> 10^5 organisms/ml= significant and probable infection
<10^3 organisms/ml= not significant bacteirurua
10^4= repeat specimen
54
kass criteria used with
caution as it is for females of child bearing age, in men counts may be lower even if an infection is present because of prostatic anti-bacterial factor
55
pure growth vs mixed growth
a genuine UTI in a non-catheterised patient is usually caused by a single organism (>10^5 organism/ml of pure growth) mixed growth (2 or more organisms) even if more than 10^5 organisms/ ml is not significatn
56
exception to the pure vs mixed growth rule
this rule does not apply to catheterised or patients with abnormalities of the urinary tract
57
Treatment of an uncomplicated lower UTI the ideal antibiotic
should be excreted in high concentration into the urine, oral and have few side affects
58
abacterial cystitis/ urethral syndrome
patient has symptoms of UTI, pus cell in there urine but no significant growth on culture
59
abacterial/ urethral syndrome may be caused by
- early phase of a UTI
- honeymoon cystitis caused by urethral trauma during sex
- urethritis caused by gonorrhoea/ chlamydia
60
treatment of bacterial cystitis/ urethral syndrome
antibiotics are Not USED alkalinising the urine amy relieve symptoms
61
asymptomatic bacteriuria
more than 10^5 organisms/ ml on culture but ht patient is ASYMPTOMATIC therefore, the condition is detected incidentally
62
in asymptomatic bacteirura there are no
pus cells in the urine
63
management of asymptomatic bacteririuria
ANTIBIOTICS ARE NOT REQUIRED EXCEPT IN PREGNANCY WHERE IT IS ALWAYS TREATED:
- all woman are screen at there first ante-natal visit at 3 months if untreated 20-30% of people develop pyelonephritis and it can cause intra-uterine growth retardation and premature labour
64
catheter related UTI is
one of the commonest hospital acquired infections however, the loner a catheter is in situ the more likely it is to become colonised with bacteria so catheterised patients with > 10^5 Organisms/ml should only be given antibiotics if they are symptomatic because necessary antibiotics cause the catheter to become colonised with increasingly resistant micro-organisms
65
antibiotics used for a female lower UTI (uncomplicated cystitis)
oral trimethoprim or nitrofurantoin for 3 days
66
recurrent UTI
2 or more in 6 months or 3 or more in one year
67
prophylaxis for recurrent UTIS
trimethoprim or nitrofurantoin at night and review after 6-12 months
68
uncatheterised male UTI (uncomplicated UTI)
should always be cultured: oral trimethoprim or nitrofurantoin for 7 days
69
complicated UTI or pyelonephritis managed in general practise
oral co-amoxicla or oral co-trimoxazole for 14 dya
70
complicated UTI or pyelonephritis managed in hospital
IV amoxicillin and gentamicin for 3 dyas (co-trimoxazoel and gentamicin if penicillin allergic)
71
amoxicillin and co-trimoxazole cover
enterococci 40% of coliforms
72
gentamicin covers
coliforms
73
trimethoprim covers
the lower urinary tract
74
gentamicin can only be give
IV
75
gentamicin should not be used in
pregnancy
76
gentamicin has
a very narrow therapeutic window and is nephrotoxic and ototoxic
77
UTI AND ESBL PRODUCING BACTERIA
Bacteria is resistant to all cephalosporins and all almost all penicillin
78
ESBL is carried on a
plasmid which often carried genes for restiqtn to other antibiotics i.e. gentamicin and ciprofloxacin
79
antibiotics that may be useful in ESBL
nitrofurantoin, meropene, fosftomycin
80
carbapenemase producen enterobaceriace
gram negatice (coliform) bacilli wchih are resistant to meropenem and all current antibiotics
81
2nd line antibiotics for coliforms
aztreonam and pivmecillinam
82
2nd line antibiotics for enterococcus
vancomycin
83
trimethoprim (oral)
inhibits folic acid synthesis so DO NOT USE IN FIRST TRIMESTER OF PREGNANCY
84
Trimethoprim covers
coliforms, staph aureus, MRSA but NOT pseudomonas aerguinosa
85
nitrofurantoin is only useful for
lower uncomplicated UTIS as it only reaches effective concentrations in the bladder urine
86
do not use nitrofurantoin
late in pregnancy as there is risk of neonatal haemolysis, do not use in breastfeeding or children under 3 months old
87
nitrofurantoin covers
most coliforms, enterococci, staph aura including MRSA but NOT proteus or pseudomonas
88
amoxicillin
- high concentrations reached in urine can be given oral or IV
- SAFE IN PREGNANCY
- COVERS ENTEROCCOCUS AND SOME COLIFORMS BUT MORE THAN 50% OF E.COLI ARE NOW RESISTANT
89
Pivmecillinam (oral)
useful for treatment of lower uncomplicated uTI and has activity against ESBL but no activity against staph strep enterccoi or pseudomonas
90
temocillin
useful in treating complicated UTIS who's renal function is too poor to tolerate Gentamicin
91
carbapenems
active against ESBLS
