Urinary tract infection (UTI)
Urinary tract infection (UTI)
• What is a urinary tract infection?
– Urinary tract is the system that makes urine
• and carries it out of the body
– It includes bladder and kidneys
• and the tubes that connect them
– When germs get into this system
• they can cause an infection
– Most urinary tract infections are bladder infections
• not serious if it is treated right away
– If not take care of a bladder infection
• it can spread to the kidneys
• A kidney infection is serious and can cause permanent damage
What causes urinary tract infections?
• Usually, germs get into our system through urethra
• The germs that usually cause these infections live in large intestine
– and are found in stool
• If these germs get inside urethra
– they can travel up into bladder and kidneys and cause an infection
• Women tend to get more bladder infections than men
– women have shorter urethras
– Sexual intercourse may move bacteria into the urinary tract, especially
in women
• You may be more likely to get an infection if
– you do not drink enough fluids, you have diabetes, or you are pregnant
• The chance to get a bladder infection is higher if you have any problem
that blocks the flow of urine from bladder
• Catheters are a common source of bacterial infection in people who are in
hospitals or who live in long-term care facilities
• Sometimes bacteria traveling through the blood or lymph
system cause kidney or bladder infections
• Kidney stones, an enlarged prostate in men, and structural problems in the
urinary tract can contribute to UTIs by limiting the body's ability to
eliminate urine completely
What are lower urinary tract symptoms ?
– The lower urinary tract system includes the bladder
and urethra
– In practice, the majority of LUTS are caused by urine
infections in the bladder
– LUTS are divided into two groups:
• symptoms caused by irritation of the bladder and urethra
• symptoms due to blockage (obstruction) to the flow of urine
• Symptoms due to irritation of the bladder and urethra:
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Burning or stinging when you pee (urinate)
Constant lower tummy (abdominal) ache
An urgent feeling of needing to empty your bladder
Loss of bladder control (Incontinence)
Needing to get up to urinate several times in the night and more often
than usual during the day
– Feeling generally unwell and achy
– Fever - temperature above 37°C
• Symptoms due to obstruction:
– Feeling of needing to empty your bladder even after urinating
– Difficulty urinating
– A slow stream of urine
Risk factors
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Risk factors in women
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UTIs are most common in young to middle-aged sexually active women.
Things that increase a woman's risk of getting UTIs include
Sexual activity, which pushes bacteria into the urethra
Pregnancy
Previous UTIs
Lack of estrogen, which allows bacteria that can cause UTIs to grow more easily in
the vagina or urethra
Women who have gone through menopause are at increased risk for UTIs
Risk factors in men
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Problems with the prostate gland
Men become increasingly prone to UTIs as they get older because of prostate problems
An uncircumcised penis
Anal intercourse
Unprotected sex with a woman who has a vaginal infection
HIV infection
•
Risk factors in both women and men
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Not drinking enough fluids
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Having a catheter in place
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These may block the flow of urine, raising the risk of bacterial infection
Diabetes
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Bacteria can enter the catheter and start an infection
Kidney stones and other obstructions in the urinary tract
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Drinking more fluids causes increased urination, reducing bacteria in the urinary tract and bladder
immune systems are weakened
long-term high blood sugar can damage the kidneys' filtering system (diabetic nephropathy)
Structural problems of the urinary tract
–
These may be present at birth or develop later in life
Complications
• When treated promptly and properly, lower urinary
tract infections rarely lead to complications. But left
untreated, a urinary tract infection can have serious
consequences.
• Complications of UTIs may include
– Recurrent infections, especially in women who experience
three or more UTIs
– Permanent kidney damage from an acute or chronic
kidney infection (pyelonephritis) due to an untreated UTI,
especially in young children
– Increased risk of women delivering low birth weight or
premature infants
Lower Urinary tract infection
• Cystitis
– Is the inflammation of urinary bladder (the sac that temporarily holds
urine until urination) caused by microbial colonization and infection
– This type of UTI is usually caused by Escherichia coli (E. coli)
• Hemorrhagic cystitis
– Is characterized by large quantities of visible blood in the urine
– It can be caused by an infection (bacterial or adenovirus)
• Urethritis
– It is the inflammation of urethra (the tube that carries urine from the
bladder during urination) caused by microbial infection
– This type of UTI can occur when GI bacteria spread from the anus to
the urethra
Etiology of Cystitis and Urethritis
(Non-Sexual origin)
• Causes
• Pathogens may ascending the urethra of fecal origin
• 1- Escherichia coli (80–85% of urinary tract infections)
• 2- Staphylococcus saprophyticus
• 3- Other genera of Enterobacteriaceae
– Klebsiella, Enterobacter, Proteus, and Serratia.
• 4- Pseudomonas aeruginosa
– (Hospital-acquired infection due to contaminated catheter)
• 5- Enterococcus faecalis
– ( Hospital-acquired infection due to contaminated catheter)
Tests and diagnosis
• Analyzing a urine sample
• Growing urinary tract bacteria in a lab
• Creating images of urinary tract
• Using a scope to see inside bladder
Laboratory diagnosis of UTI
• Collection of Urine Clinical Specimens
• A- Midstream catch urine: One to Ten mL
– must be collected in sterile urine container , the first portion
must be discarded to avoid contamination with urethra and
vaginal bacteria
• B- Catheterized Urine: One to Ten mL
– Must be collected in sterile urine container.
• C- Suprapubic Urine: One to Ten mL
– Aspirated from urinary bladder by fine needle collected in sterile
anaerobic tube
• (young babies, children, obstruction cases)
Cultivation of urine specimens:
• Urine specimens should be cultivated on Enriched media (blood agar) and
differential media (MacConkey’s agar or CLED) by the following methods:
• 1- Four quadrant streaking method
– depends on Calibrated Loop
– Semi-quantitative
• 2- Network Streaking method
– depends on Calibrated Loop
– quantitative
• 3- Microbroth dilution method
– Quantitative
– calibrated loop carry only one microliter
Isolation of microbe from urine and calculation of CFU :
Bacterial loop carry one microlitre.
When 50 colonies are isolated = 50 cells per/1 µl = 50 CFU/ µl
In one mL : 50 * 1000= 50000 CFU/mL.
CFU cutoff value and significant
bacteriuria
• The CFU cutoff value is associated with type of urine
specimens
• It is calculated to be equal to
– For Midstream catch urine: 50000- 100000 CFU/m L.
– For Catheterized Urine:
100 CFU/m L.
– For Suprapubic Urine:
Any growth.
• Significant bacteriuria:
– Is the isolation of microbes of infectious dose cutoff value from
urine
– Specimen in presence of signs and symptoms of UTI
– It is mainly associated with pyuria and dysuria
Isolation of Enterobacteriaceae from urine specimens:
The most important genera that could be isolated from urine are:
Escherichia coli , Klebsiella, Enterobacter, Proteus mirabilis, and
Serratia species.
Enterobacteriaceae genera are classified according to lactose
fermentation into two groups:
1- Lactose none fermenters.
2- Lactose fermenters.
Identification of E. coli:
-Some strains of uropathogenic E. coli are verotoxin producers.
-All strains are oxidase negative and catalase positive.
-Metallic green sheen on EMB agar.
-Uropathogenic E. coli species are indole positive.
Differentiation of Lactose fermenter genera by IMViC test:
A
Indole
Methyl-red
Vogus-Pros
Citrate
E.coli
+
+
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Citrobacter
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+
Klebsiella
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-
+
+
Enterobacter
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-
+
+
The Rapid biochemical identification system: The API20E:
n
Identification of Proteus species:
All species are Gram’s negative bacilli that illustrate swarming
growth on blood agar.
All are H2S and urease positive.
Isolation of Pseudomonas species from urine specimens:
Cultural characteristics:
-All species of Pseudomonas produce Water soluble Exopigment on
nutrient agar. (greenish yellowish pyoverdin) .
-All species are oxidase positive.
Isolation of Serratia marcescens from urine:
Microorganisms that produce pigment during growth are said to be
chromogenic.
Serratia marcescens produces a deep red pigment ( water-insoluble)
at 25°C, but does not produce pigment at 37°C.
Serratia marcescens
Pseudomonas
Isolation of Gram’s positive Cocci :
-The most important Gram’s positive Cocci that associated with UTI
are:
1-Staphylococcus saprophyticus.
2-Enterococcus faecalis.
-Staphylococcus aureus is also considered as a causative agent of UTI.
Differentiation of Staphylococcus aureus and other Staphylococcus
species:
-All Staphylococcus species are Gram’s positive Cocci arranged in
clusters.
-All species are Catalase positive.
-Staphylococcus aureus are coagulase positive.
-Staphylococcus epidermidis and Staphylococcus saprophyticus are
coagulase negative.
Staph. aureus
coagulase positive
Other Staph.
Coagulase negative.
n
-Staphylococcus saprophyticus species are Mannitol fermenters and
Novobiocin resistant.
Novobiocin sensitive Staph.
Mannitol fermentation pattern.
Isolation of Enterococcus faecalis from urine specimens:
Urine specimens should be cultivated on bile esculine salt agar
when Nosocomial UTI is suspected.
Black discoloration of media is a distinctive characteristics of group
D streptococcus growth (Enterococcus faecalis).
Parasitic infection of urinary system:
Schistosomiasis:
Classification (phylum): Trematoda.
Classification according to morphology:
Flattened non-segmented unisexual flukes.
Schistosoma hematobium:
• Found in Middle East, Africa, Portugal and Cyprus
• Definitive host: man
• Intermediate host: snail
• It causes urinary bilharziasis (female deposits eggs in the
vesical and pelvic plexus of venous circulation).
n
Male:
10-20 x I mm with short anterior cylindrical pan and posterior
flattened part which incurved ventrally to form the gynaeccphoric
canal.
It has well developed oral and ventral suckers.
Female:
15-25 x 0.25 mm:, cylindrical, ovary may
"be central, anterior or posterior, uterus
may be short or long containing eggs.
Schistosoma hematobium ova:
-140x50 µ, oval with terminal spine.
-Passes in urine.
Life cycle:
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CLINICAL PICTURE:
The clinical picture is divided into three stage:
1-Incubation period; (acute Schistosomiasis 6-12 Weeks) :
This stage is characterized by skin irritation after coming from
water, and coughing.
Late in the incubation period, patients complains of enlarged
liver, fever, headache, anorexia, loss of weigh.
CBC shows Eosinophilia.
2- Stage of egg deposition: (1- 5 years after infection).
Urinary bilharziasis:
caused by S.hematobium, characterized by terminal haematuria,
burning sensation during urination.
n
3-Stage of complication:
-Due to a fibrosis around the eggs in bladder, liver and
lung.
- Obstruction of bladder.
Urinary bilharziasis:
cystitis, hydronephrosis and
Pyonephrosis ,
sterility in males, renal failure,
urinary bladder carcinoma,
pulmonary hypertension and
heart failure.
Prevention
• Take these steps to reduce your risk of urinary tract
infections
– Drink plenty of liquids, especially water
• Drinking water helps dilute your urine and ensures that you'll urinate
more frequently — allowing bacteria to be flushed from your urinary
tract before an infection can begin
– Wipe from front to back
• Doing so after urinating and after a bowel movement helps prevent
bacteria in the anal region from spreading to the vagina and urethra
– Empty your bladder soon after intercourse
• Also, drink a full glass of water to help flush bacteria
– Avoid potentially irritating feminine products
• Using deodorant sprays or other feminine products, such as douches
and powders, in the genital area can irritate the urethra