This document provides an overview of urinary tract infections (UTIs). It discusses what constitutes a UTI, common causes like E. coli, and risk factors like female anatomy. Symptoms vary by age but include issues like frequency and pain. Diagnosis involves urine tests to check for bacteria, white blood cells, and nitrites. Treatment generally involves antibiotics like trimethoprim that achieve high urine concentrations. Duration depends on the infection type, with uncomplicated cystitis often treated with a 3 day course and pyelonephritis requiring longer treatment.

1. UNRINARY TRACT INFECTION

2. Introduction
• UTI  presence of organisms in the urinary tract together with
symptoms and sometimes signs of inflammation
• Significant bacteriuria  presence of at least 100, 000 bacteria / ml
of urine (small number of bacteria are normally found in anterior
urethra and may be washed out into urine samples
• Count of fewer than 1000 bacteria / ml are normally considered to be
urethral contaminants  exceptional clinical circumstances such as
immunosuppressed patients.
• Asymptomatic bacteriuria  significant bacteriuria in the absence of
symptoms in the patient
• Cystitis  a syndrome of frequency, dysuria and urgency which
usually suggests infection restricted to the lower urinary tract
baldder and urethra

3. • Urethral syndrome: a syndrome of frequency and dysuria in the
absence of significant bacteriuria with a conventional pathogen.
• Acute pyelonephritis: an acute infection of one or both kidneys.
Usually, the lower urinary tract is also involved.
• Chronic pyelonephritis: It can refer to continuous excretion of
bacteria from the kidney, to frequent recurring infection of the renal
tissue or to a particular type of pathology of the kidney seen
microscopically or by radiographic imaging, which may or may not be
due to infection. Although chronic infections of renal tissue are
relatively rare, they do occur in the presence of kidney stones and in
tuberculosis.

4. • Relapse and reinfection: recurrence of urinary infection may be due
to either relapse or reinfection. Relapse is recurrence caused by the
same organism that caused the original infection.
• Reinfection is recurrence caused by a different organism, and is
therefore a new infection.

5. Etiology and Risk Factors
• Uncomplicated-community acquired  E.coli --80% of infections
• Gram-negative enteric bacteria  Klebsiella & Proteus
• Gram-positive cocci (enterococci and Staphylococcus
saprophyticus*) (20%)
• [*entirely restricted to young sexually active women]
• UTI associated with underlying structural abnormalities  congenital
anomalies, neurogenic bladder and obstructive uropathy 
Pseudomonas aeruginosa, Enterobacter and Serratia spp (more
resistant)  implicated in hospital acquired urinary infections
(patients with urinary catheters).
• Rare causes  anaerobic bacteria & fungi (associated with structural
abnormalities or catheterization)

6. Pathogenesis
• Three possible routes (organisms might reach UT)
• Ascending
• Blood-borne and
• Lymphatic (little evidence)
• Blood-borne  bacteremic illnesses (Staphylococcus aureus)
• UTI in women  colonization of the vagina, perineum and periurethral area
by the pathogen  ascends into the bladder via the urethra.
• Uropathogens colonize the urethral opening of men and women.
• Urethra in women is shorter than in men  More Chances of UTI in females
• Sexual intercourse (more chances in females)
• Circumcision (less chances in males)
•

7. Clinical Manifestation
• Most UTIs are asymptomatic.
• Symptoms, when they do occur, are principally the result of irritation of the bladder and
urethral mucosa.
• Clinical features of UTI are extremely variable and to some extent depend on the age of the
patient.
Babies and Infants
• Often overlooked or misdiagnosed because the signs may not be referable to the urinary
tract.
• Common but non-specific presenting symptoms include failure to thrive, vomiting, fever,
diarrhoea and apathy.
• UTI in infancy and childhood is a major risk factor for the development of renal scarring,
which in turn is associated with future complications such as
chronic pyelonephritis in adulthood, hypertension and renal failure.
Children
• Above the age of 2, children with UTI  classic symptoms such as frequency, dysuria and
haematuria
• children present with acute abdominal pain and vomiting, and this may be so marked as to
raise suspicions of appendicitis or other intra-abdominal pathology.

8. Adults
• Typical symptoms of lower UTI  frequency, dysuria, urgency and
haematuria.
• Acute pyelonephritis (upper UTI)  fever, rigors and loin pain in addition to
lower tract symptoms.
• Systemic symptoms may vary from insignificant to extreme malaise.
• Untreated cystitis rarely progresses to pyelonephritis, and bacteriuria does
not seem to carry the adverse long-term consequences that it does in
children.
Elderly
• UTI is frequent in the elderly, great majority of cases are asymptomatic, and
even when present, symptoms are not diagnostic because frequency,
dysuria, hesitancy and incontinence are fairly common in elderly people
without infection.

9. Investigation
• Uncontaminated urine sample  microscopy and culture
• Dipsticks  rapid near-patient for urinary blood, protein, ntrites and
leukocyte esterase (reliable when applied to fresh urine samples)
• Assessment of color changes on dipstick
• Leukocyte esterase test  enzyme released from leukocyte in urine
and is 90% sensitive to detect WBCs count of >10/mm (it is even
positive even if cells have destroyed due to delay in transport to lab)
• Presence of leukocyte is common UTI
• Nitrite test (Griess test)  urinary nitrite produced by bacteria
(commonly causing UTI)
• Other spp. Such as enterococci, group B streptococci, Pseudomonas
 do not  lack converting enzymes
• Microscopy  a drop of uncentrifuged urine is placed on a slide,
covered with coverslip and examined 40 X objective
• Excessive WBCs  symptomatic UTI

10. Investigation
• Culture  quantify the number of bacteria in urine specimen (as
when urine passes via urethra contamination occurs)
• True infections may be associated with low counts, particularly when
the urine is very dilute because of excessive fluid intake or where the
pathogen is slow growing.
• quantitative criterion for ‘significant’ bacteriuria is generally taken as
>100,000/mL, in some specific groups, it is less: for men >1000/mL
and for women with symptoms of UTI  >100/mL

11. Treatment
• Symptomatic UTI  antibiotic treatment to eradicate both
symptoms and pathogen
• Asymptomatic  may or may not need treatment depending upon
the circumstances of individual case
• Bacteriuria in children and women requires treatment (same as in the
case of surgical manipulation of UT)
• Unnecessary treatment  bacterial resistance and increased risk of
adverse drug effects including bowel infection with Clostridium
difficile (associated with cephalosporins & quinolones)
• Non-specific treatment
• Drink lot of fluids
• Urinary analgesics i.e. Potassium or Sodium citrate (alkalinise urine) +
antibiotics (avoid when nitrofurantoin is used  requires low pH)

12. Treatment
• Antimicrobial Therapy
• Principles of antimicrobial treatment are same as for other infections
(based on efficacy, safety and cost)
• Agent selected  narrow spectrum and for shortest possible time
• No evidence of superiority of bactericidal agents over bacteriostatic
• Most significant aspect is to have maximum conc. Of drug in urine
• Blood levels are important  pyelonephritis (progresses to
bacteremia)
• Cystitis  oral treatment  trimethoprim, beta-lactams (amoxicillin,
co-amoxiclav, cefalexin), quinolones (ciprofloxacin, norfloxacin,
ofloxacin & nitrofurantoin)
• I.V treatment  amoxicillin, cefuroxime, quinolones &
aminoglycosides (gentamicin)
• Penicillins and cephalosporins are relatively non-toxic  agents of
choice (renal failure)

13. Treatment
• Duration of treatment
• For men, traditionally, a course of 7–10 days and this is still the recommendation
for treating men with prostatitis
• For women short-course regimens such as 3-day or even single-dose therapy.
• The consensus of an international expert working group was that 3-day regimens
are as effective as longer regimens in the cases of trimethoprim and quinolones. β-
Lactams
• Children  The drugs of choice include β-lactams, trimethoprim and
nitrofurantoin. Children should be treated for 7–10 days
• Acute pyelonephritis  Suitable agents with good activity against E. coli and other
Gram-negative bacilli  cephalosporins (cefuroxime and ceftazidime), some
penicillins (co-amoxiclav), quinolones, and aminoglycosides (gentamicin)
• First-choice agent  cefuroxime, gentamicin or ciprofloxacin (I.V)
• Route of administration may be switched to oral therapy, typically using a
quinolone. Conventionally, treatment is continued for 10–14 days.

16. • Relapsing UTI  The main causes of persistent relapsing UTI are renal infection,
structural abnormalities of the urinary tract and chronic prostatitis (men).
• Patients who fail on a 7–10-day course should be given a 2-week course, and if that
fails, a 6-week course can be considered
• In men with prostate gland infection, it is appropriate to select antibiotics with good
tissue penetration such as trimethoprim and fluoroquinolones.
• Catheter-associated infection  (10-15% patients in hospitals are catheterized Even
with the very best catheter care, most will have infected urine after 10–14 days of
catheterization  most of these infections will be asymptomatic.
• Do not treat asymptomatic infection.
• If possible, remove the catheter before treating symptomatic infection.
• Antimicrobial catheters  antibiotics such as rifampicin and minocycline or silver-
based alloys into the catheter have shown benefit