UTIs-Definition

1. UTIs-Definition • Infectious diseases of the urinary tract: • cystitis (bladder) • pyelonephritis (kidney) • prostatitis (prostate)

2. Etiology • Usually Acute • Majority due to a single pathogen • Usually an Enterobacteriaceae • 90% of all UTI • gram negative bacilli • common intestinal flora • Escherichia coli most commonly isolated pathogen ~80% of all UTI

3. Gram staining Gram –ve E. coli Gram +ve S. aureus

4. Organisms: • Gram -ve • Cause 90-95% of UTI’s • most often, E. coli. • Others include: • Proteus mirabilis and Klebsiella. • Gram +ve • pathogens include: • Staph saprophyticus, • Staph aureus, • group A beta hemolytic streptococci and enterococci.

5. Features of UTI • Common affliction to seek medical attention. • Infancy to old age • Bacturia: • bacteria in urine • does not necessarily imply infection

6. Features of UTI • Pyuria • Presence of WBCs in urine • Evidence of inflammatory response to infection.

7. Epidemiology • Populations with increased incidences: • School age girls • Young women>men • >50% have a UTI during their lifetime • >10% per year have a UTI • Pregnant women • Elderly of both sexes • Diabetes • Abnormal urine flow

8. Children with recurrent infection Monitoring antibiotic therapy High risk individual Who to screen for UTI?

9. How do we screen for UTIs? • Collect midstream urine • use fresh or refrigerate. • Pour about 10 ml in tube and dipstick. • Microscopy • Culture

10. Chemical Analysis • Dip-stick testing • Quick • Efficient • Inexpensive • Large number of substances

11. Chemical Analysis

12. Chemical Analysis

13. Chemical Analysis

14. Urinalysis • Dipstick findings: • leukocyte esterase + with pyuria • nitrite + with Enterobacteriaceae • alkaline pH with urea splitting bacteria, e.g., Proteus mirabilis • high specific gravity if patient is volume depleted • protein often + • blood may be +

15. What are the most useful test? • Leukocyte Esterase • Enzyme found WBCs • More reliable than microscopic analysis for WBCs • Positive results indicate inflammation in the path taken by urine. • Includes urethra, prostate, cervix and vagina • Occur in 90 to 95% of symptomatic UTI • Less sensitive asymptomatic UTI in elderly and pregnancy • Significant result: positive

16. What are the most useful test? • Nitrite • Some bacteria will convert Nitrate to Nitrite • Good indicator of contact of urine with bacteria • Detects 2/3 to ¾ of all UTIs • But… • Gram +ve bacteria do not cause a positive result • Negative results do not rule out infection • Significant Result: Positive

17. Microscopic Urinalysis

18. Urinalysis • Centrifuge for 5 min at 2000 rpm, pour off supernatant; examine sediment with microscope using high power objective. • Microscopic findings: • <5 leukocytes per high power field (hpf) • more = pyuria • 1 bacterium per hpf correlates with >100,000 per ml; • 1 bacterium = 1 colony forming unit (cfu) • hematuria

19. Urine Culture • Quantitative: uncentrifuged urine inoculated on an agar plate to do a colony count. • Appropriate agars: 5% sheep blood and eosin-methylene blue or MacConkey. • Incubate: at 35-37o C for 24 hours.

20. E. Coli in Urine Culture

21. Urine Culture • Significant bacteriuria: • by 24 hour colony count • cystitis: >100 cfu per ml • pyelonephritis: >100,000 cfu/ml • Species identification. • Susceptibility testing • urine for C&S.

22. A secure diagnosis of UTI requires a urine culture

23. How the test is done

24. Urinary Bacteria Detection Kits • Two Uses • Patients susceptible to UTI • Monitor effectiveness of Treatment • Detect urinary nitrites associated with gram-negative bacterial infections.

25. How the Test Works: Nitrites Gram -ve Pathogen Nitrite Nitrate in Acidic Urine Meat, Fish & Eggs P-Arsanilic Acid Diazonium Compound Pink Color N-(1-naphthyl) -ethylenediamine

26. How the Test Works: Leukocytes White Blood Cells in Urinary Tract White Blood Cells in Urine INFECTION/INFLAMMATORY RESPONSE Pyrrole Ester Compound Leukocyte esterase Color Diazo Reagent Pyrrole

27. Sampling precautions • Clean Dry Container • First Morning Urine or in Bladder >4 hrs • Fresh sample • Follow-up: Regardless of result. • Test Sensitivity • 90% - 3 consecutive mornings • 10% - False negative rate

28. Factors Affecting Test • Concentration of Gram -ve Bacteria • > 100,000/mL of urine • Time in the Bladder • Contamination • Blood • Adequate Dietary Nitrates • Most people Consume sufficient Quantities • Drug interference • Alkaline Urine • Ascorbic Acid (Vitamin C)>250 mg • Antibiotics and Drugs that turn urine red

29. Home Cholesterol Tests • Two Uses • Monitor progress on Lipid lowering drugs and diet • Save Time and Costs of Physician Visits • Err on the side of false positives • Multiple measurements should be evaluated • Measurement errors and day to day biological and behavioral changes contribute to variations in cholesterol levels

31. How the Test Works Few Drops of Blood 10 Filter Step 1 Plasma (Cholesterol & Cholesterol esters) Step 2a 1. Wick Flow of Plasma 2. Cholesterol Oxidase/Esterase 3.2 Step 2b Colored Dye Cholest-4-ene-3-one H2O2 Peroxidase

32. Factors Affecting Test • Finger Pricking Technique • Hanging Drops • Squeezing and Milking • Time to Collect • Low results if > 5 min. • Blood Volume

33. ?Usefulness • Test only measures Total Cholesterol • Laboratories measure LDL, HDL, triglyceride, and cholesterol. • All are required. • You cannot make a judgement on cardiovascular risk on Cholesterol alone. • If values >5.2 : Discuss with physician • If values<5.2: Check Cholesterol again at next visit with a physician

34. Other kits • Drugs of Abuse • Cannabinoids • Cocaine • Amphetamines • Benzodiazepines • Barbiturates • Opiates • Combinations • Home tests for STDs • Home tests for monitoring DM complications

35. This new product measures cholesterol plus other things using a test strip • Predict in as greatest detail you can how it might works… • What factors do you think could affect the reliability of the test results?