Urinary Tract Infections (UTIs)

1

• ??? ???? ??????? ???????

2

• Urinary Tract Infections (UTIs)

3
Introduction

• UTIs are common, especially among women
• UTIs in men are less common and primarily
• occur after 50 years of age
• UTIs infection usually occur by ascending
  route (urethra to bladder)
• UTIs infection is less common by haematogenous
  spread (kidney)
• UTIs occur in two general settings
  community-acquired and hospital (nosocomially)
  acquired

4
Definitions

• Urethritis Infection of anterior urethral
  tract
• dysuria, urgency
• and frequency of
  micturition
• - Dysuria (burning
  pain on passing urine)
• - Urgency (the urgent need to
  pas urine)
• - Frequency of micturition ???? ???? ??????
  
• Cystitis Infection of urinary bladder
• dysuria, frequency, pyuria
  and
• haematuria
• Bacteriuria Presence of bacteria in urine
• A count of 10? organisms/ml or more in urine
  
• Pyuria Presence of pus in urine
• (more than 10 cells/HPF)

5
Etiology Of Urinary Tract Infections

• Causative organisms
• Escherichia coli
• Klebsiella,
  proteus and pseudomonas
• 1- Bacterial S. aureus, S.
  epidermidis and S. saprophyticus
• Enterococci
  (Strept. faecalis)
• Mycobacterium
  tuberculosis
• Chlamydia
  trachomatis, Mycoplasma
• 2- Viral Rubella, Mumps and
  HIV
• 3- Fungal Candida, Histoplasma
  capsulatum
• 4- Protozoal T. vaginalis, S.
  haematobium

6
Notes on pathogens

• Escherichia coli the commonest urinary
  pathogen
• causing 60-90 of urinary infections
• Pseudomonas, Proteus, Klebsiella and S. aureus
  
• are associated with hospital acquired
  infections because their resistance to
  antibiotics favor their selection in hospital
  patients
• (catheterization, gynaecological surgery)
• Proteus infections are associated with renal
  stones
• Proteus produce a potent urease which act on
  ammonia, rendering the urine alkaline
• S. saprohyticus infections are found in
• sexually active young women

7
Notes on pathogens

• Candida urinary infection is usually found in
  diabetic patients and immunosuppression
• Infection of the anterior urinary tract
  (urethritis) is mainly caused by N. gonorrhoae,
  staphylococci, streptococci and chlamydiae
• M. tuberculosis is carried in blood to kidney
  from another site of infection
• (e.g. respiratory T.B.)

8
Mechanical And Functional Factors Predispose to
UTI

• Disruption of urine flow or complete emptying
  of bladder
• - Pregnancy - Renal stones -Tumor
• - Prostate hypertrophy - Strictures
  narowing of ureter
• Loss of neurologic control of bladder and
  sphincters
• Paraplegia, and multiple sclerosis
• Paraplegia ??? ???? ?? ???????
• multiple sclerosis ????? ???? ??? ????? ????
  ?????
• Vesicouretral reflux
• (reflux of urine from bladder up the ureter)
• Anatomic abnormalities in children
• Catheterization facilitate bacterial access to
  bladder
• - During insertion
• - In situ, bacteria access to bladder

9
Virulence Factors of Causative Organisms

• - Fimbriae enable adherence to urethral
  epithelium
• - Capsular polysaccharide inhibite
  phagocytosis
• - Haemolysin production by E. coli
• -Membrane damaging toxin
• - Production of urease enzyme (proteus spp.)

10
Healthy Urinary Tract

• Bacterial colonization in urinary tract is
• prevented by
• - pH of urine (acidic)
• - Chemical content of urine
• - Flushing mechanisms ?????? ?????

11
Clinical Features

• Acute lower UTIs (Urithritis and cystitis)
• Rapid onset of
• - Dysuria (burning pain on
  passing urine)
• - Urgency (the urgent need to
  pas urine)
• - Frequency of micturition
• Upper UTIs (Pyelonephritis)
• - Fever
• - Chills
• - Dysuria
• - Urgency
• - Frequency of micturition

12
Difference between infected and contaminated urine

• Infection
  Contamination
• More than 105 Organisms/ml less than
  104 Organisms/ml
• A single bacterial spp.
  More than one organism

13
Diagnosis of Urinary Tract Infections

• Specimen Urine
• - An aseptic collection technique essential to
  prevent contamination
• - The first urine passed by patient in the
  morning
• - A mid stream urine sample under a septic
  precaution
• - Boric acid is used as a preservative for
  urine specimens
• Special urine specimens are required to detect
• a- Mycobacterium tuberculosis
  
  
• Three early morning urine samples on 3
  consecutive days
• b- S.haematobium
• The last few milliliters of a morning
  urine sample after exercise

14
Diagnosis of Urinary Tract Infections

• Detection of significant bacteruria
• a- Microscopic examination
• - Wet film to detect
• . Pus cells, red cells, casts,
  yeasts
• . Bacteria T.vaginalis, S.
  haematobium
• b- Viable bacterial count
• - A measured volume (calibrated loop
  0.002 ml)
• of urine is spread on surface of a
  solid medium
• - Incubation of the solid medium at
  37C for
• 18-24 hours
• - Enumerate the number of colonies

15
Diagnosis of Urinary Tract Infections (cont.)

• c- Cultures
• - Culture is required when urine contain
  bacteria, cells, casts, protein,nitrite
• - Nutrient agar, CLED agar, Blood agar and
  MacConkeys medium at 37C
• - Isolated colonies are identified in a
  systematic way
• 1- Microscopical examination
• Gram staining to differentiate
  between Gm negative and Gm positive
• Shape, size and arrangement
• 2- Biochemical reactions
• - For Gm negative organisms Sugar
  fermentation, Indol test,
• 
  Oxidase, MR, VP and urease tests
• - For Gm positive organisms Coagulase
  test, catalase test
• 3- Serological identification
  Detection of microbial Ag by specific Ab

16
Sterile Pyuria

• - Presence of pus in urine in absence of
  bacterial growth
• - Causes
• a- Infection with Chlamydia trachomatis
• M. tuberculosis
• Ureaplasma
  
• Anaerobic
  bacteria
• Mycoplasma and
  L-forms
• Viruses
• b- Previous antibiotic therapy
• (Suppress growth of bacteria)

17
Treatment

• Uncomplicated UTI
• An oral antibacterial as a single dose or
  for 3 days
• Complicated UTI (Pyelonephritis)
• Treatment with a systematic antibacterial
  agent
• e.g. Beta-lactam (Ampicillin, amoxicillin,
  cefalexin)
• Quinolone (Ciprofloxacin,
  levofloxacin)

18

• Thank you