Urinary tract infection
A urinary tract infection (UTI) is an
infection that affects part of the urinary
tract.
1] When it affects the lower urinary
tract it is known as a bladder infection
(cystitis) and when it affects the upper
urinary tract it is known as kidney
infection (pyelonephritis).
Symptoms
from a lower urinary tract include pain
with urination, frequent urination, and
feeling the need to urinate despite
having an empty bladder.
Symptoms of upper urinary track infection
Symptoms of a kidney infection include fever and
flank pain usually in addition to the
symptoms of a lower UTI. Rarely the
urine may appear bloody.
In the very old and the very young, symptoms may
be vague or non-specific.
Urinary tract infection
Synonyms Acute cystitis, simple
cystitis, bladder
infection, symptomatic bacteria
referred to as a bladder infection. The
most common symptoms are burning
with urination and having to urinate
frequently (or an urge to urinate) in the
absence of vaginal discharge and
significant pain.
[4] These symptoms
may vary from mild to severe
[9] and in
healthy women last an average of
six days.
Some pain above the pubic
bone or in the lower back may be
present. People experiencing an upper
urinary tract infection, or pyelonephritis,
may experience flank pain, fever, or
nausea and vomiting in addition to the
classic symptoms of a lower urinary
Couses
Uropathogenic E. coli from the gut is
the cause of 80–85% of community-
acquired urinary tract infections,with
Staphylococcus saprophyticus being
the cause in 5–10%.
Rarely they may
be due to viral or fungal infections.
Healthcare-associated urinary tract
infections (mostly related to urinary
catheterization) involve a much broader
range of pathogens including: E. coli
(27%), Klebsiella (11%), Pseudomonas
(11%), the fungal pathogen Candida
albicans (9%), and Enterococcus (7%)
among others. Urinary tract
infections due to Staphylococcus
Pathogenesis
The bacteria that cause urinary tract
infections typically enter the bladder
via the urethra. However, infection may
also occur via the blood or lymph. It is
believed that the bacteria are usually
transmitted to the urethra from the
bowel, with females at greater risk due
to their anatomy. After gaining entry to
the bladder, E. Coli are able to attach to
the bladder wall and form a biofilm that
resists the body's immune response.
Escherichia coli is the single most
common microorganism, followed by Klebsiella and Proteus spp., to cause
urinary tract infection. Klebsiella and
Proteus spp., are frequently associated
with stone disease. The presence of
Gram positive bacteria such as
Enterococcus and Staphylococcus
increased.
The increased resistance of urinary
pathogens to quinolones has been
reported worldwide and might be the
consequence of overuse and misuse of
quinolones.
Diagnosis
In straightforward cases, a diagnosis
may be made and treatment given
based on symptoms alone without
further laboratory confirmation.
[4]
In
complicated or questionable cases, it
may be useful to confirm the diagnosis
via urinalysis, looking for the presence
Multiple bacilli (rod-shaped bacteria, here shown
as black and bean-shaped) shown between
white blood cells in urinary microscopy. These
changes are indicative of a urinary tract infection.
of urinary nitrites, white blood cells
(leukocytes), or leukocyte esterase.
Another test, urine microscopy, looks
for the presence of red blood cells,
white blood cells, or bacteria. Urine
culture is deemed positive if it shows a
bacterial colony count of greater than
or equal to 10
3 colony-forming units
per mL of a typical urinary tract
organism. Antibiotic sensitivity can also
be tested with these cultures, making
them useful in the selection of antibiotic
treatment. However, women with
negative cultures may still improve with
antibiotic treatment.
For those with recurrent infections,
taking a short course of antibiotics
when each infection occurs is
associated with the lowest antibiotic
use.
] A prolonged course of daily
antibiotics is also effective.
Medications frequently used include
nitrofurantoin and
trimethoprim/sulfamethoxazole
(TMP/SMX).
Methenamine is another
agent used for this purpose as in the
bladder where the acidity is low it
produces formaldehyde to which
resistance does not develop.
Some
recommend against prolonged use due
A urinary tract infection (UTI) is an
infection that affects part of the urinary
tract.
1] When it affects the lower urinary
tract it is known as a bladder infection
(cystitis) and when it affects the upper
urinary tract it is known as kidney
infection (pyelonephritis).
Symptoms
from a lower urinary tract include pain
with urination, frequent urination, and
feeling the need to urinate despite
having an empty bladder.
Symptoms of upper urinary track infection
Symptoms of a kidney infection include fever and
flank pain usually in addition to the
symptoms of a lower UTI. Rarely the
urine may appear bloody.
In the very old and the very young, symptoms may
be vague or non-specific.
Urinary tract infection
Synonyms Acute cystitis, simple
cystitis, bladder
infection, symptomatic bacteria
referred to as a bladder infection. The
most common symptoms are burning
with urination and having to urinate
frequently (or an urge to urinate) in the
absence of vaginal discharge and
significant pain.
[4] These symptoms
may vary from mild to severe
[9] and in
healthy women last an average of
six days.
Some pain above the pubic
bone or in the lower back may be
present. People experiencing an upper
urinary tract infection, or pyelonephritis,
may experience flank pain, fever, or
nausea and vomiting in addition to the
classic symptoms of a lower urinary
Couses
Uropathogenic E. coli from the gut is
the cause of 80–85% of community-
acquired urinary tract infections,with
Staphylococcus saprophyticus being
the cause in 5–10%.
Rarely they may
be due to viral or fungal infections.
Healthcare-associated urinary tract
infections (mostly related to urinary
catheterization) involve a much broader
range of pathogens including: E. coli
(27%), Klebsiella (11%), Pseudomonas
(11%), the fungal pathogen Candida
albicans (9%), and Enterococcus (7%)
among others. Urinary tract
infections due to Staphylococcus
Pathogenesis
The bacteria that cause urinary tract
infections typically enter the bladder
via the urethra. However, infection may
also occur via the blood or lymph. It is
believed that the bacteria are usually
transmitted to the urethra from the
bowel, with females at greater risk due
to their anatomy. After gaining entry to
the bladder, E. Coli are able to attach to
the bladder wall and form a biofilm that
resists the body's immune response.
Escherichia coli is the single most
common microorganism, followed by Klebsiella and Proteus spp., to cause
urinary tract infection. Klebsiella and
Proteus spp., are frequently associated
with stone disease. The presence of
Gram positive bacteria such as
Enterococcus and Staphylococcus
increased.
The increased resistance of urinary
pathogens to quinolones has been
reported worldwide and might be the
consequence of overuse and misuse of
quinolones.
Diagnosis
In straightforward cases, a diagnosis
may be made and treatment given
based on symptoms alone without
further laboratory confirmation.
[4]
In
complicated or questionable cases, it
may be useful to confirm the diagnosis
via urinalysis, looking for the presence
Multiple bacilli (rod-shaped bacteria, here shown
as black and bean-shaped) shown between
white blood cells in urinary microscopy. These
changes are indicative of a urinary tract infection.
of urinary nitrites, white blood cells
(leukocytes), or leukocyte esterase.
Another test, urine microscopy, looks
for the presence of red blood cells,
white blood cells, or bacteria. Urine
culture is deemed positive if it shows a
bacterial colony count of greater than
or equal to 10
3 colony-forming units
per mL of a typical urinary tract
organism. Antibiotic sensitivity can also
be tested with these cultures, making
them useful in the selection of antibiotic
treatment. However, women with
negative cultures may still improve with
antibiotic treatment.
For those with recurrent infections,
taking a short course of antibiotics
when each infection occurs is
associated with the lowest antibiotic
use.
] A prolonged course of daily
antibiotics is also effective.
Medications frequently used include
nitrofurantoin and
trimethoprim/sulfamethoxazole
(TMP/SMX).
Methenamine is another
agent used for this purpose as in the
bladder where the acidity is low it
produces formaldehyde to which
resistance does not develop.
Some
recommend against prolonged use due
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