Patient 1

Source: http://kidney.niddk.nih.gov/kudiseases/pubs/utiadult/

Introduction

The urinary system consists of the kidneys, ureters, bladder, and urethra. The key elements in the system are the kidneys, a pair of purplish-brown organs located below the ribs toward the middle of the back. The kidneys remove excess liquid and wastes from the blood in the form of urine, keep a stable balance of salts and other substances in the blood, and produce a hormone that aids the formation of red blood cells. Narrow tubes called ureters carry urine from the kidneys to the bladder, a sack-like organ in the lower abdomen. Urine is stored in the bladder and emptied through the urethra. (http://kidney.niddk.nih.gov/kudiseases/pubs/utiadult/)

One woman in five develops a UTI during her lifetime. Women tend to get them more often because their urethra is shorter and closer to the anus. UTIs in men are not as common as in women but can be very serious when they do occur.

Bacterial UTIs can be classified according to localization as urethritis (inflammation of the urethra), cystitis (inflammation of the bladder), or pyelonephritis (inflammation of the kidney).

Causes

Usually urine is sterile, free from fungi, bacteria or viruses. An infection only occurs after microbes, usually bacteria present in the gut manage to cling onto the urethra and begin to multiply.

Escherichia (E.) coli is responsible for between 75% and 90% of uncomplicated cystitis cases in younger women and in more than half the cases in older women. Staphylococcus saprophyticus accounts for 5% to 15% of UTIs, mostly in younger women. Klebsiella, Enterococci bacteria, and Proteus mirabilis account for most of remaining bacterial agents that cause UTIs. They are generally found in UTIs in older women.

Rare bacterial causes of UTIs include ureaplasma urealyticum and Mycoplasma hominis, which are generally harmless organisms.

Organisms responsible for UTI:

• Bacteria
• Escherichia coli
• Proteus mirabilis
• Klebsiella
• Pseudomonas aeruginosa
• Serratia
  
• Enterobacter
• Staphylococcus epidermis
• Enteroccocus
  
• Salmonella typhi
• Mycobacterium tuberculosis
• Staphylococcus aureus
• Viruses
• Polyomavirus JC
• Polyomavirus BK
  
• Cytomegalovirus
• Adenovirus
• Fungi
• Candida albicans and other Candida spp.
• Histoplasma capsulatum
  

Source : http://everything2.com/index.pl?node=urinary%20tract%20infection

Sample Collection

A midstream urine specimen of 2 – 15 ml should be collected in a sterile plastic wide-mouthed container. It should reach the laboratory within 2 hours of collection; otherwise refrigeration (for up to 24 hours) is advised. Relevant clinical information should be provided along with the patient sample.

Diagnosing

UFEME

The urine specimen must first be dip tested for the presence of blood cells, both erythrocytes and leukocytes, nitrates and protein. It should then be sent of to the microbiology lab for culturing and antibiotic susceptibility tests.

A high count of leukocytes in the urine is referred to as pyuria. (A leukocyte count over 10 per microliter is considered to indicate pyuria.) This is very accurate in identifying the disease when it's present, but it also tests positive in many people who do not have a UTI. Pyuria is usually sufficient for a diagnosis of UTI in nonhospitalized patients if other standard symptoms (or just fever in small children) are also present.

Culture

The agar plates that are used in the culture of the microbe of the urine specimen are Blood agar, MacConkey agar and Cled agar. UTI is nearly always caused by a single species of bacteria, notably E. coli.

MacConkey – Differentiate between Gram-negative by inhibiting the growth of Gram-positive bacteria.

Blood – is a differential media used to isolate fastidious organisms and detect hemolytic activity.

Cled – isolation and differentiation of urinary organisms.

If microorganisms, are isolated, they are then identified by performing biochemical tests. Normally, a gram stain is done first. Depending on their colour stain, shape and their gram category, biochemical tests are done to determine their identity. Just to name a few, a catalase or coagulase test might have to be performed.

Sensitivity

After cultivation on the agar plates, the organism is then checked for resistance to any type of antibiotics. This will assist the clinician in prescribing the right type of drug to the patient for quick recovery.

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