UTI microbiology Flashcards
(101 cards)
1
Q
what is a lower UTI
A
infection confined to the bladder= cystitis
2
Q
what is an upper UTI
A
infection onvolving the ureters +/- the kidneys (pyelonephritis)
3
Q
urine where is sterile
A
kidneys, ureters and bladder
4
Q
is the urethra sterile
A
no colonised by bacteria (coliforms and enterococci from the large bowel due to the proximity to the anus)
5
Q
what types of bacteria usually colonise the urether
A
coliforms and enterococci (from large bowel)
6
Q
what is a complicated UTI
A
UTI complicated by systemic symptoms or urinary structural abnormalities/ stones
7
Q
what is bacteriuiria
A
bacteria in the urine- doesnt always mean infection (esp in elderly patients/ catheterised patients)
8
Q
what is cystitis
A
inflammation of the bladder- not always due to infection
9
Q
what are the risk factors for a UTI
A
women > men (short, wide urethra, proximity of urethra to anus, increased risk with sexual activity/ pregnancy)
catheterisation
abnormalities of the urinary tract
10
Q
what is the path of an ascending infection
A
bacteria from bowel- perineal skin- lower end of urethra- bladder- ureters- kidneys
11
Q
what is the path of infection from the blood to the urinary system (this is rare)
A
bacteraemia- seeded into kidneys
- small multiple abscesses- bacteria in urine
12
Q
what specimen do you want to diagnose a UTI
A
mid stream urine (first part of stream washes out lower colonised urethera- in STIs want first part of urinary stream)
dipstick/ culture
microscopy
13
Q
what are coliforms
A
gram negative bacteria
14
Q
name the gram -ve bacteria that commonly cause UTIs
A
coliforms (gram -ve bacilli):
- E COLI
- klebsiella
- enterobacter
- serratia
- citribacter
- morganella
- proteus
- providencia
not coliforms:
-pseudomonas aeruginosa
15
Q
what is the most common cause of UTIs
A
e coli
16
Q
what is the only non coliform that commonly causes UTIs
A
pseudomonas aurginosa
17
Q
what type of bacteria is e coli
A
gram negative coliform
18
Q
what is the key virulence factor of e coli for UTIs
A
endotoxin in LOS layer
19
Q
what type of bacteria is proteus
A
gram negative coliform
20
Q
what is proteus associated with - why
A
struvite stones (stag horn calculi)
produces urase which breaks down urea to form ammonia - increases urinary pH- precipitation of salts
21
Q
what are the features of proteus
A
swarming cultures foul smelling (burnt chocolate)
22
Q
what is urothiasis and what infection is it associated with
A
kidney stone formation
=proteus infection
23
Q
what is pseudomonas associated with
A
catheters and instrumentation
24
Q
what antibiotics for pseudomonas aeruginosa
A
RESISTANT TO MOST ORAL except ciprofloxacin (quinolone)
25
who cant take ciprofloxacin
young children and pregnant women (is a quinolone)
26
how does ciprofloxacin work
inhibits bacterial DNA gyrase
27
what does ciproloxacin treat
pseudomonas, almost all coliforms, some enterococci but NOT s aureus or MRSA
28
how can you give ciprofloxavin
oral or IV
29
what is the only oral anti-psuedomonal antibiotic
ciprofloxacin
30
what are the SE of ciprofloxacin
tendonitis, tendon ruptures, seizures
31
what are the gram positive causes of UTIs
enterococcus:
- ENTEROCOCCUS FAECALIS
- enterococcis faecium
staph:
staphylococcus saphrophyticus
staph aureus (uncommon)
32
what is associated with gram enterococcus (gram +ve) UTI associated with
hospital acquired infections
33
what type of bacteria is staph saphrophyticus
coagulase negative staph
| usually affects women of child bearing age
34
what does a staph saphrophyticus UTI cause
UTI in women of child bearing age
| causes cystitis in community
35
when do you get staph aureus UTIs
uncommon (usually bacteraemia)
36
what are the symptoms of a UTI
dysuria
frequency of urination
nocturia
haematuria
37
what are the symptoms of an upper UTI
fever
loin pain
rigors
38
what are the symptoms of cystitis
```
frequent and urgent urination
dysuria
suprapubic pain
nocturia
haematuria
malaise
```
39
what usually causes cystitis
e coli
klebsiella
staph saprophyticus
enterococcus faecalis
40
what are the risk factors for cystitis (lower UTI)
```
female
history of UTI
vaginal infection
diabetes
obesity
genetic susceptibility
```
41
what are the risk factors for polynephritis (upper UTI)
diabetes
HIV/AIDS
iatrogenic immunosuppression
congenital or acquired urodynamic abnormalities
42
what are the symptoms of pyelonephritis
back and/or flank pain
fever, chills, malaise
nausea, vomiting, anorexia
43
what are the common causative organisms of pyelonephritis
```
e coli
klebsiella
staph aureus
enterococcus faecalis
proteus
```
44
what are the alternative methods of urine specimen collection
suprapubic aspiration
straight in/out catheter
clean catch (children, cognitive/ physical restriction)
bag urine (babies- only negative culture useful as often contaminated)
45
what is the process of collecting a mod stream specimen of urine
Label appropriate laboratory container
(Wash perineum / urethral meatus with sterile saline (not antiseptic))
Give patient a suitable wide mouthed sterile (foil) bowl
First urine passed into toilet
Without interruption ,Next part of urine stream collected in bowl
Last urine passed in toilet
Urine transfer from bowl to appropriate laboratory container
46
what are the transport options for urine samples
boricon contain (contains boric acid- stops bacteria replicating, work for 24 hrs)
sterile universal container (must get to lab in 2 hrs)
47
when and how can dipstick be used to see if there is infection
in selective patients
leukocyte esterase shows presence of leukocytes in urine (WBC)
nitrites indicate presence of bacteria in the urine
48
when would a UTI give a negative nitrite dipstick test
many coliforms reduce nitrates to nitrites so do not give a positive test
(enterococcus, staph, pseudomonas)
protein + blood
49
WHEN DO YOU NOT DO A DIPSTICK FOR UTI
DO NOT DIPSTICK URINE OF ELDERLY/ CATHETER PATIENTS FOR INFECTION!!!!
50
is microscopy of urine done commonly
no
| can be used to look for pus, bacteria +/- red cells
51
what is kass's criteria
criteria showing the likelyhood of women of childbearing age having a UTI depending on the number of organisms found in culture (>10*5 organisms/ ml= probable UTI)
52
what does pure/ mixed growth on a urine culture mean
genuine UTI (in non catheterised patients) will be caused by a single organism
mixed growth is probably not significant
53
what should an ideal antibiotic for a UTI be
excreted in urine high concentration
oral
inexpensive
few SE
54
how long a course of antibiotics for an uncomplicated UTI in women
3 day course
55
what is abacterial cystitis/ urethral syndrome
patient has symptoms of UTI and pus in urine but no significant growth on culture:
- may be an early phase of UTI
- may be due to urethral trauma (honeymoon cystitis)
- may be due to urethritis caused by chlamydia, gonnorhoea
56
what can help in abacterial cystitis/ uretheral syndrome
alkalinising the urine may provide symptomatic relief
57
what is asymptomatic bacteriuria
significant bacteruria (>10*5 orgs/mL)
patient is asymptomatic (found incidentally)
no pus cells in urine
antibiotic treatment not required, especially in elderly
if you give antibiotics will recur
58
who are the only people who should get antibiotics in asymptomatic bacteriuria
```
pregnant women (all screened at first antenatal visit for it)
if left untreated can 20-30% progress to pyelonephritis which can cause intra-uterine growth retardation/ premature labour
```
59
when should catheterised patients with >10*5 orgs/mL be given antibiotics
when there is supporting evidence of UTI (fevers, symptoms)
unnecessary antibiotics result in catheter becoming colonised with increasingly resistant organisms
60
empirical Tx for female lower UTI
nitrofurantoin or trimethoprim orally 3 days
61
empirical Tx for uncatherterised male UTI
get cultures- need to consider prostatitis
nitrofuratoin or trimethoprim orally for 7 days
62
empirical Tx for complicated UTI or pyelonephritis GP
co amoxiclav or co trimoxazole for 14 days
63
empirical Tx for complicated UTI or pyelonephritis hospital
amoxicillin and gentamicin IV for 3 days
| co trimoxazole and gentamcin if allergic
64
what antibiotics for coliforms
gentamicin IV
amoxicillin
trimethoprim (lower tract)
co trimoxazole
65
what antibiotic for enterococci
amoxicllin IV
| cotrimoxazole
66
what are the 1st and 2nd line antibiotics for UTI
```
1st line
amoxicillin (IV, oral)
trimethoprim (oral, but can be given IV as cotrimoxazole)
nitrofurantoin (oral)
gentamicin (IV)
```
```
2nd line
pivmecillinam (oral)
temocillin (IV)
cefalexin (oral)
co-amoxiclav = amoxicillin + clavulanic acid (IV, oral)
ciprofloxacin (IV, oral)
```
67
what is the workhorse for gram -ves
gentamicin (IV)
68
how do you give gentamicin
hospital use only- has to be given IV
should be prescribed for 3 days only
69
what does gentamicin not treat
enterococci
70
who should you avoid giving gentamicin to
pregnant women
71
what is ESBL
extended spectrum beta lactamase
72
what does ESBL make bacteria resistant to
all cephalosporins and to almost all penicillins
73
what antibiotics may be useful in EBSL
```
nitrofuratoin oral
pivemecillinam oral
fosfomycin oral
temocillin IV
meropenem IV
ertapenem IV
```
74
what are carbapenemase producing enterobacteriaceae
gram negative coliform that are resistent to meropenem= effectively resistant to all current antibiotics
75
what antibiotic for anterococci
amoxicillin
76
what 2nd lines doe gram -ves
```
Aztreonam
Egfr <20 , more expensive
Pivmecillinam (po)
Temocillin (ESBL
Piperacillin/tazobactam
Meropenem
Quinonoles (e.g. ciprofloxacin)
fosfomycin
```
77
what 2nd line antibiotics for enterococci
```
Vancomycin
(chloramphenicol)
Linezolid
(Daptomycin)
(tigecycline)
```
78
how does trimethoprim work
Inhibits bacterial folic acid synthesis
avoid in 1st trimester (3 months) of pregnancy
most coliforms, Staph aureus incl. MRSA but not Pseudomonas sp.
79
why is nitrofurantoin only useful for lower UTIs
as reaches effective conc in bladder
80
when should you avoid nitrofuratoin
late pregnancy (can cause neonatal haemolysis), breast feeding and children <3 months old
81
what does nitrofuratoin treat
Most coliforms, Enterococci, Staph aureus incl MRSA, but not Proteus sp and Pseudomonas sp.
82
what does amoxillin treat
Enterococcus faecalis
| Some coliforms, but >50% E coli now resistant, and many other coliforms also resistant
83
when is cefalexin used
when organisms is amoxicillin and trimethoprim resistant
84
what does co amoxiclav treat
Most coliforms, enterococci, Staph aureus but not MRSA, not Pseudomonas sp
85
when is temocillin useful and not useful
Useful for treating complicated UTI/urosepsis in patients whose renal function is too poor for gentamicin, but is NOT as effective as gentamicin clinically
NO activity against Staphylococci/Streptococci/Enterococci or Pseudomonas sp.
86
what are the carbepenems
active against ESBL producers
meropenem
ertapenem
not against staph/strep/enterococci/ pseudomonas
87
when is pevmecillinam used
has activity against ESBL, useful in uncomplicated UTI
doesnt work against staph/strep/enterococci or pseudomonas
NOT in pregnancy
88
why is e coli the most common cause of UTI
most common aerobe in bowel- proximity of anus to urethra
89
why is nitrofuratoin a suitable choice for the treatment of cystitis but not for pyelonephritis
concentrates in the bladder, not high enough concentration in kidneys to be affective
90
antibiotic for pyelonpehritis in GP
co-amoxiclav
91
what do you use to calculate the dose of gentamicin
body weight, gender, age, height, creatinine
92
what is the workhorse against gram -ves
gentamicin
93
why is erythromycin not suitable for pyelopnephritis in penicillin hypersensitive patient
not excreted by kidneys and is bacteriostatic (in pyelonephritis eant bacteriocidal)
94
in a patient with symptoms of a UTI why might a urine culture be negative
poor sample
if already started antibiotics
aseptic cystitis
95
what treatment for aseptic cystitis
emptying bladder after sex
| alkalising urine with sodium citrate but no evidence for this
96
what diagnosis if recurrent aseptic cystitis persitis
STI
| recurrent cystitis
97
what antibiotic for mild c diff
PO metronidazole
98
do you send a stool culture after c diff symptoms resolve for a test of cure
no
99
what antibiotics for a UTI in a pregnancy women
nitrofluritone oral in 1st trimester
| trimethoprim in 2nd/3rd semester
100
what can a dipstick tell you about presence of an infection
A negative dip stick test for leukocyte esterase (white cells) is a useful test to rule out UTI when combined with a negative nitrite test (negative predictive
value of 95%)
101
what should you test if both blood an protein are present on dipstick
CRP, ANA, ANCA
and protein electrophoresis to look for other causes such as vasculitis or
myeloma
