Infections Of The Genitourinary Tractaa.pptx

Overview of genitourinary tract Infections

1. Infections Of The Genitourinary Tract Haftom L. AD U , CMHS ) 1

2. Overview of genitourinary tract Infections Infections of the genitourinary tract include: infections of the bladder, kidney, and prostate infections of the vagina sexually transmitted infections. 2

3. Infections of the urinary tract Infections of the urinary tract include urethritis cystitis pyelonephritis prostatitis These infections are very common, each year result in over 7 million physician office visits about 1 million hospitalizations. Most UTIs result from contamination of the urethra with organisms found in the colon 3

4. Ascending urinary tract infection 4

5. INFECTIONS OF THE URETHRA, BLADDER, AND KIDNEY A urinary tract infection occurs when bacteria and white blood cells are present in the urine of a patient with symptoms of infection of the urethra, urinary bladder, or the kidney. Bacteriuria : bacteria are present in the urine Pyuria : white blood cells are present in the urine. 5

6. Symptoms of urethritis and cystitis (Lower UT) usually occur simultaneously. However, infection of the lower urinary tract does not always result in infection and symptoms of infection in the upper urinary tract (e.g. pyelonephritis ). The bacteria that cause urinary tract infections are usually of fecal origin (e.g., Escherichia coli) 6

7. The most common cause of urinary tract infections is E coli. Staphylococcus saprophyticus is the second most common cause of these infections in sexually active females. In complicated cases of urinary tract infections, the most common causes are E coli, Klebsiella pneumoniae , Proteus mirabilis, Enterococcus , and Pseudomonas aeruginosa . 7

8. MANIFESTATIONS Urethritis is an infection of the urethra that causes pain and discomfort during voiding ( dysuria ). Cystitis is an infection of the urinary bladder. Signs and symptoms of cystitis include urgency and frequency of urination , voiding small volumes of urine, and suprapubic tenderness just before or immediately after voiding . Patients who have symptoms of cystitis will also have symptoms of urethritis . 8

9. In most cases of pyelonephritis , an infection of the lower urinary tract ascends the ureters to enter the kidneys. As a result, a patient with pyelonephritis will usually experience many of the signs and symptoms of urethritis and cystitis. 9

10. EPIDEMIOLOGY Urinary tract infections rank second only to respiratory infections in their incidence Most cases of urinary tract infection occur in women female to male ratio is 30:1. The incidence of urinary tract infections increases with age and with sexual activity . About 40% of all females have at least one urinary tract infection at some time in their lives. 10

11. Postmenopausal women have higher rates of infection because of bladder or uterine prolapse loss of estrogen loss of lactobacilli in the vaginal flora 11

12. Urinary tract infections are usually endogenous ; infection follows contamination of the distal end of the urethra with bacteria from the patient’s own fecal organisms. Urinary tract infections occasionally occur following bacteremia or due to hematogenous spread of a distant infection to the urinary tract. 12

13. PATHOGENESIS The organisms that commonly cause urinary tract infections are found in feces. Ascension of the organisms up the urethra to the bladder is the most common means of acquiring a urinary tract infection. Blood-borne infections of the urinary tract can occur but are infrequent and usually lead to renal abscess 13

14. 14 Ascending urinary tract infection

15. Host factors that are important in protection from urinary tract infections include The normal daily flow of urine The constant sloughing of the uroepithelial cells lining the urinary tract The presence of large numbers of Lactobacillus in the vaginal mucosa 15

16. Females develop urinary tract infections more frequently than males the shorter urethra and the close proxim ity of the urethra to the anus. sexual intercourse promotes contamination of the urethral opening with fecal organisms Some women have many more urinary tract infections than other sexually active women in their age group have more E. coli receptors on the cells that line the urinary bladder ( uroepithelial cells). 16

17. Risk Factors for Urinary Tract Infections 17

18. Any anatomic obstruction or neurologic disorder leading to incomplete elimination of urine from the bladder can also lead to urinary tract infection. 18

19. Pyelonephritis , or infection of the kidneys, is due to ascent of bacterial infection from the urinary bladder via the ureters . The kidneys are protected from infection due to the presence of a sphincter at the distal end of each ureter by movement of urine from the kidneys to the bladder by peristalsis Any factor leading to retrograde flow of urine from the urinary bladder to the kidney will predispose the host to pyelonephritis 19

20. Predisposing Factors that Cause Pyelonephritis 20

21. Bacteria that gain access to the kidney can cause damage by production of Polysaccharide Hemolysins Endotoxin 21

22. Kidney stones can serve as a location in which bacteria can escape antibiotics and cause recurrent urinary tract infections. Proteus can cause stones to form when it produces an enzyme called urease . 22

23. DIAGNOSIS Signs and symptoms are important in determining a diagnosis in a patient with a UTI. A patient with dysuria and increased frequency and urgency is likely to have urethritis and cystitis. symptoms unique to pyelonephritis indicate that the patient also has a kidney infection. 23

24. Urinalysis should be performed in patients symptomatic for urethritis and cystitis without kidney involvement to determine the urine pH and if there is pyuria bacteriuria If the pH is > 7.9 and the urine contains bacteria and white blood cells, the patient usually has a urinary tract infection due to urease -producing Proteus species 24

25. Bacteriuria can be determined using a dipstick test to check for the presence of nitrites in the urine . Many uropathogens convert nitrates to nitrites when growing in urine. Enterococcus and S. saprophyticus do not produce nitrites in human urine and yield false-negative results. If patients have a nitrite-negative cystitis , urine should be obtained and the specimen should be plated on growth media 25

26. If there are clinical manifestations of pyelonephritis as well as cystitis,the following tests can be performed to confirm the diagnosis of pyelonephritis . An antibody-coated bacterial urine test Microscopic wet mount of spun urine Blood cultures 26

27. Escherichia coli The Most Prevalent Enteric Bacillus Causes different disease :- Sepsis, UTI , meningitis and gastroenteritis  Posses three antigens O , K and H antigens (used for classification) There are over 700 serotypes  Are the most isolates from sepsis (45%)  Responsible for 80-90% UTI  Responsible for the majority gastroenteritis in developing countries  Most infections are endogenous (except strains to meningitis and GE)  Indicator of water contamination 27

28. Virulent factors 1. Adhesins  Adhesions – are also called colonization factors and include both pili or fimbriae and non- fimbrial factors involved in attachment (e.g. intimin ). Adhesins protects from flushing of urine and intestinal motility There are at least 21 different types of adhesions. Antibodies to these may protect from colonization. 28

29. 2. Toxins Exotoxins Heat stable toxins STa and STb Shiga toxins Stx-1 and Stx-2 Hemolysin Heat labile toxin LT-1 and LT-2 Endotoxin 29

30. Specialized Virulence Factors Associated with E. coli EAEC UPEC EPEC ETEC Type 1 pili UPEC UPEC EIEC ETEC ETEC EHEC UPEC 30

31. Clinical disease UTIs (due to uropathogenic E.coli ) Is the leading cause of urinary tract infections which can lead to acute cystitis (bladder infection) and pyelonephritis (kidney infection). comes from colon (anus)  urethra  ascends to bladder  kidney or prostate  Commonly caused by strains equipped with different adhesins 31

32. Binds tightly to cells lining in bladder and upper urinary tract Produce hemolysin which lysis RBC and other cells and leads to cytokines release and stimulation of inflammation response 32

33. Staphylococcus saprophyticus belongs to the genus Staphylococcus. Staphylococci are all catalase -positive, gram-positive cocci usually arranged in clusters (singles, diplococci , and short chains in tissues). is nonhemolytic , coagulase negative, and resistant to novobiocin when cultured on blood agar. is nitrite negative. 33

34. S. saprophyticus causes urinary tract infections, particularly in sexually active young women. Most women with this infection have had sexual intercourse within the previous 24 hours. This organism is second to Escherichia coli as a cause of community-acquired urinary tract infections in young women. 34

35. Proteus mirabilis is a gram-negative, motile short rod. produces a typical swarming growth on blood agar. is primarily an opportunist, transmitted via catheters. Attributes of pathogenicity produces a powerful urease that hydrolyzes urea to ammonia and CO 2 . results in stones and calculi, leading to urinary tract obstruction 35

36. The organisms are present in the human colon as well as in soil and water Their tendency to cause urinary tract infections is probably due to their presence in the colon and to colonization of the urethra The vigorous motility of Proteus organisms may contribute to their ability to invade the urinary tract. 36

37. Enterococcus faecalis was formerly classified as group D streptococci. occurs as part of the normal intestinal and oral flora in humans and animals. is a facultative anaerobic, gram-positive coccus . Organisms are generally noninvasive opportunists; however, they are a leading cause of nosocomial infections Clinical disease includes urinary tract infections , septicemia, and associated endocarditis 37

38. Pseudomonas aeruginosa Motile (by single or multiple polar flagella) gram-negative rods Obligate (strict) aerobes (most strains) Oxidase and catalase positive Some strains produce diffusible pigments : Pyocyanin (blue); fluorescein (yellow); pyorubin (red) P. aeruginosa produces characteristic grape-like odor and blue-green pus & colonies 38

39. Virulence factors Pili : Adhere to epithelial cells 2.Exopolysaccharide: Anti- phagocytic property/ inhibit pulmonary clearance 3. Lipopolysaccharide : Endotoxic effect 4. Enzymes - Elastases: Digests protein (elastin, collagen, IgG) - Proteases - Hemolysins - Phospholipases C (heat labile): Degrade cytoplasmic membrane components 5. Exotoxin A : Cytotoxic by blocking protein synthesis 39

40. Virulence Factors Associated with Pseudomonas aeruginosa 40

41. P. aeruginosa can be found in the intestinal tract, water , soil and sewage and is frequently found in moist environments in hospitals It is able to grow in some eye drops (especially quaternary ammonium compounds), saline and other aqueous solutions. Because of this, many infections with P. aeruginosa are opportunistic hospital-acquired , affecting those already in poor health and Immuno -suppressed. 41

42. Urinary tract infections Urinary tract infections (UTI) caused by Pseudomonas aeruginosa are usually hospital-acquired and related to urinary tract catheterization , instrumentation or surgery. Pseudomonas aeruginosa is the third leading cause of hospital-acquired UTIs Accounting for about 12 percent of all infections of this type 42

43. The bacterium appears to be among the most adherent of common urinary pathogens to the bladder uroepithelium . As E. coli UTI can occur via an ascending or descending route In addition, Pseudomonas can invade the bloodstream from the urinary tract, and this is the source of nearly 40 percent of Pseudomonas bacteremias . 43

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