Infection of urinary system

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Q: What is the definition of a Urinary Tract Infection (UTI) according to the source?

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A: A UTI is an infection that can occur in any area of the urinary tract, including the ureters, bladder, kidneys, or urethra1.

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Q: Where do Urinary Tract Infections usually develop first?

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A: Urinary tract infections usually develop first in the lower urinary tract (urethra, bladder)2.

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Q: What can happen if lower urinary tract infections are not treated?

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A: If these infections are not treated, they may progress to the upper urinary tract (ureters, kidneys)2.

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Q: What is considered the most common type of UTI?

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A: Bladder infection (cystitis) is the most common UTI2.

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Q: What are the names for infections of the urethra and the kidneys, respectively?

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A: Infection of the urethra is called Urethritis2. Infection of the kidneys is called Pyelonephritis2.

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Q: How serious is Pyelonephritis?

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A: Pyelonephritis is a serious condition that requires urgent treatment and can lead to reduced kidney function and possibly even death in untreated, severe cases2.

Signs and Symptoms of UTI

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Q: What are the signs and symptoms listed for Cystitis?

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A: The signs and symptoms for Cystitis are Dysuria, urgency, and frequency2.

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Q: What are the signs and symptoms listed for Pyelonephritis?

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A: The signs and symptoms for Pyelonephritis are Flank pain with tenderness, and dysuria, urgency3.

Causative Pathogens of UTI

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Q: List the causative pathogens of UTIs mentioned in the source.

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A: The causative pathogens listed include E. coli, Klebsiella, Proteus, Pseudomonas, Streptococcus faecalis, Staphylococcus aureus, S. epidermidis, S. saprophyticus, Mycobacterium tuberculosis, Ureaplasma urealyticum, and Chlamydia3.

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Q: Which of the listed pathogens are the most common causes of UTIs?

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A: The most common pathogens are E. coli, Klebsiella, Proteus and Pseudomonas3.

Characteristics of Common Causative Organisms

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Q: What are some general characteristics of Escherichia coli?

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A: E. coli inhabits the normal intestinal flora4. Morphologically, they are Gram negative bacilli, motile, and non sporulated4. They are facultative anaerobes and produce rose pink colonies on MacConkey’s agar4. They ferment glucose, maltose, mannite, and sucrose with acid and gas production4. The IMVC tests are Indole and Methyl red positive, Voges-Proskauer and Citrate negative4. Serologically, they have O antigens (heat-stable somatic), H antigens (flagellar), and K (capsular) antigen5.

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Q: How often is E. coli responsible for Urinary Tract Infections?

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A: E. coli is responsible for 80% of Urinary Tract Infection cases5.

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Q: What are some general characteristics of Klebsiella?

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A: Klebsiella are non motile and capsulated Gram negative bacilli6. They are facultative anaerobes and give pink, large, and mucoid colonies on MacConkey's agar due to their polysaccharide capsule7. Biochemically, they ferment glucose, maltose, mannite, and sucrose with acid and gas production7, and are negative for indole and methyl red, but positive for voges-proskauer and citrate7.

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Q: What are some general characteristics of Proteus?

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A: Proteus are pleomorphic Gram negative bacilli, motile by peritrichious flagella8. They are facultative anaerobes and swarm across the surface of simple media8. Biochemically, they are non lactose fermenter, H2S positive, and urease positive8.

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Q: What are some general characteristics of Pseudomonas?

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A: P. aeruginosa is a Gram negative rod, motile by a single polar flagellum9. It grows well on most laboratory media, is able to grow at 42°C, and has a specific fruity odor9. It produces two exopigments: the fluorescent pigment pyoverdin and pyorubin9. Biochemically, it is oxidase positive and ferments no sugar9.

Bacterial Pathogenesis and Virulence Factors

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Q: What are some virulence factors of E. coli that contribute to UTIs?

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A: Virulence factors include bacterial adherence to mucosal surfaces (e.g., via fimbriae like P, type 1, and S)10, Motility by flagella (helps in nutrient acquisition and dissemination)10, Biofilm formation (protects against phagocytosis and antibiotics)11, LPS (protection against immune system)11, Siderophores (scavenge iron)11, and Toxins (e.g., α-hemolysin and CNF1, which damage host tissues)12.

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Q: What are some virulence factors of Klebsiella?

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A: Virulence factors include Capsule (protects from phagocytosis)12, Adhesions or colonization factors (adhere to cells by Pili)12, and Siderophore production (supply iron)12.

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Q: What are some virulence factors of Proteus?

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A: Virulence factors include Adhesins (adhesion to uroepithelium)12, Motility (facilitates access to bladder, P. mirabilis has swarming motility)13, Toxins (e.g., Hemolysin damages cell membranes)13, Enzymes (e.g., Urease, which facilitates stone formation by increasing pH)13, Immune evasion (e.g., ZapA metalloproteinase cleaves IgA and IgG)14, and Quorum sensing14.

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Q: What are some virulence factors of Pseudomonas?

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A: Virulence factors include Siderophores (Pyoverdine and pyochelin)14, Toxins (various types)14, Biofilm formation (may protect against phagocytosis and antibiotics)14, Other secreted enzymes (most isolates are proteolytic)14, Quorum Sensing14, and Motility (important for colonization)15.

Laboratory Diagnosis of UTI

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Q: What is the recommended method for collecting a urine sample for UTI diagnosis?

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A: Mid-stream urine samples collected aseptically in universal containers are recommended15. For males, the external urethral meatus is cleaned; for females, repeated vaginal washing is recommended, and the sample is taken after separating the labia15....

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Q: How should a urine sample be collected from a catheterized patient?

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A: If a urine sample must be taken from a catheterized patient, it must be taken from the catheter itself, not from the urine bag16.

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Q: How should urine samples be transported or stored?

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A: Rapid transport of urine samples is important16. Samples can be stored for 4 hours at 4°C or with the addition of boric acid16.

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Q: How can microscopic examination help in UTI diagnosis?

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A: Direct wet film examination is used for pus cells count17. Smears are done from the urine deposit after ZN stain in suspected cases of tuberculosis17.

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Q: What is a common culture medium used for bacteriological examination of urine?

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A: Culture is often done on CLED medium17.

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Q: How is significant bacteriuria typically defined in a urine sample?

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A: More than 100,000 colonies per ml is generally considered significant bacteriuria18.

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