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:– 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• Risk factors in women

– 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

– 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

• Not drinking enough fluids– Drinking more fluids causes increased urination, reducing bacteria in the urinary tract and bladder

• Having a catheter in place– Bacteria can enter the catheter and start an infection

• Kidney stones and other obstructions in the urinary tract– These may block the flow of urine, raising the risk of bacterial infection

• Diabetes– 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

Citrate Vogus-Pros Methyl-red Indole

- - + + E.coli

+ - - - Citrobacter

+ + - - Klebsiella

+ + - - Enterobacter

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:n

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