1. infectious diseases… UTI
PHCP 402 by L. K. Sarki

2. Urinary tract infections (UTI)
UTIs are one of the most commonly occurring bacterial infections in humans.
Females have more UTIs than males
Appx. 1 in 3 females will have had a UTI by the age of 24
Appx. 25 – 40% of women in the general population will experience a UTI during their lifetime
Rate of UTI in males increases after the age of 60
UTI- presence of micro-organisms in the urinary tract
Probably bc of anatomic and physiologic diff. the female urethra iss relatively short which allow bacteria easy access to the bladde.In contrast, males are partly protected bc the urethra is longer and antimicrobial subs are secreted by the prostate

3. It becomes a problem for males after the age of 50 depending on the environment with higher incidence in long-stay hospitals
Prostatic obstruction, urethral instrumentation and surgery influence the infection rate

4. etiology
Most cases of UTI are caused by Gram-negative aerobic bacilli that originate from the bowel flora
Escherichia coli is the most common cause of community-acquired uncomplicated UTIs
upto 90% of all cases
Staphylococcus saprophyticus is also implicated
Accounting for upto 20% of UTIs in young women
Other enterobacteriaceae
Klebsiella, Proteus mirabilis

5. etiology Hospital-acquired infections
E. coli is still the most prevalent etiologic organism in hospital-acquired or other complicated UTIs
Others encountered in more often in the community-acquired infections includes
Pseudomonas aeruginosa, Serratia Enterobacter
Staphylococcus aureus
Haematogenous spread
Urinary catheterization

6. classification Based on anatomical site of involvement
Lower tract infection
Bladder (Cystitis)
Urethra (urethritis)
Prostate gland (protatitis)
Upper tract infection
Involving the kidneys (pyelonephritis)

7. classification Uncomplicated
Infection in an otherwise healthy individuals
No structural or functional abnormalities of the urinary tract that interfere with normal flow of urine or voiding mechanism
Nearly always caused by only a single organism

8. classification Complicated Obstruction to the free flow of urine
presence of a predisposing lesion of the urinary tract
e.g
Stones, indwelling catheter, prostatic hypertrophy

9. classification Recurrent Reinfection or relapse
Recurrence of bacteriuria with different micro-organism than was present before therapy
Although may occur at any time during or after completion of Tx, most appear several weeks or months later
or relapse

10. classification Relapse
Recurrence of bacteriuria caused by the same micro-organism that was present before the initiation of Tx
Mostly occur within 1-2 weeks after completion of therapy

11. classification Asymptomatic bacteriuria Common finding women
65 years of age and older
Significant bacteriuria without accompanying symptoms of a urinary tract infection

12. classification Symptomatic abacteriuria Also, acute urethral syndrome
Presence of symptoms consistent with UTI
Frequent and painful urination
but no significant bacteriuria
Commonly associated with chlamydia infection

13. pathogenesis
Heavy and persistent colonisation of the urethra and/or vaginal vestibule with intestinal bacteria leads to retrograde infection of the bladder
Defence mechanisms like
Micturation washes bacteria out of the bladder
This is effective if urine flow freely and the bladder is emptied completely

14. pathogenesis Presence of organic acids Contribute to a low pH And Urea
Contributes to a high osmolality
Prevents further spread of infection

15. pathogenesis
Infective bacteria may ascend via the ureters as a result of decreased ureteral peristalsis or vesicoureteral reflux to result in focal renal involvement

16. predisposing factors
There are many predisposing factors for the development of UTI and they include
Extremes of age
Female gender
Pregnancy
Instrumentation of the urinary tract
Urinary tract obstruction
Neurologic dysfunction

17. clinical presentation
Dysuria
Polyuria
Suprapubic pain
Loin pain
Costovertebral angle (CVA) tenderness
Fever
Chills
Haematuria
Nausea and vomiting
Usually commonly associated with Lower UTIs
Usually commonly associated with upper UTIs in addition to dysuria and polyuria

18. Lab findings Urinalysis (refer to PHCP 302) Urine culture
≥105 colonies of bacteria per millilitre confirms UTI
But note that up to 50% of actual cases of acute cystitis have <105 bacteria/ml
>103 bacteria/ml is suggestive of UTI in men
Always consider possible contamination, method of collection and time of collection of specimen in interpreting lab results

19. treatment Lower urinary tract infection (uncomplicated)
Trimethoprim-sulphamethoxazole (co-trimoxazole, bactrimR, septrinR) has been the traditional drug of choice
But resistance has developed in recent years
mg (960 mg) every 12 hours for days to be taken on empty stomach with plenty of water
Single-dose (3 tablets of 960 mg all at once) and 3-day course of therapy (960mg bid x 3/7) may be effective

20. treatment It crosses placenta and causes maternal folate antagonism
Amoxicillin + clavulanic acid (AugmentinR)
625 mg every 12 hours for 7-14 days or
Single-dose of Amoxicillin 3 g
3-day course may also be given
Nitrofurantoin
50 – 100 mg every 6 hours for 7-14 days to be taken with food or milk

21. treatment
Note that single antibiotic dose is reasonably effective in treating uncomplicated acute Lower UTIs in young adult females
The choice of agent should be based on local sensitivity pattern
Other agents used as single-dose therapy include
Nitrofurantoin 200 mg
Ciprofloxacin 500 mg
Norfloxacin 400 mg
Augmentin 625 mg

22. treatment Pyelonephritis
Because of overlap of symptoms it is usually difficult to differentiate clinically between upper and lower UTIs (i.e., subclinical pyelonephritis)
Acute pyelonephritis may lead to sepsis, therefore treatment may require hospitalisation and the use of parenteral antibiotics

23. treatment A broad-spectrum cephalosporin or quinolone may be used
E.coli remains the predominant pathogen in complicated pyelonephritis, but other Gram-negative bacteria like klebsiella, proteus and pseudomonas are found relatively more frequent

24. treatment
Third generation cephalosporin like ceftriaxone 1 g IV every 12 – 24 hours for 10 – 14 days
3rd generation cephalosporins have better coverage than 1st and 2nd generation cephalosporins against Gram-negative organisms
Aminoglycosides like gentamicin 3 mg/kg IM every 8 hours for days

25. treatment
Quinolones like ciprofloxacin mg every 12 hours for days may be used for resistant organisms
Generally, patients requiring hospitalisation should be treated with parenteral antibiotics until fluids can be taken orally, followed with a course of oral antibiotics for a total duration of antimicrobial therapy of days

26. treatment
Longer treatment for up to 21 days may be necessary in complicated pyelonephritis
Patients with mild acute pyelonephritis (no nausea, vomiting, or signs of sepsis) can be managed with oral co-trimoxazole for 14 days

27. treatment of UTI in pregnancy
Acute symptomatic pyelonephritis may develop in pregnant women with untreated bacteriuria
UTIs during pregnancy are associated with increased rates of preterm labour, premature delivery and lower birth-weight infants
Prompt screening of pregnant women for bacteriuria, and treatment with appropriate antimicrobial agent is recommended

28. treatment of UTI in pregnancy
penicillins and cephalosporins are relatively safe for use during prenancy
Co-trimoxazole, nitrofurantoin, nalidixic acid and fluoroquinolones should be avoided
Gentamicin may be used with caution when there is no suitable alternative and the benefit outweighs the risk to the fetus

29. prophylaxis
Low-dose prophylactic treatment is commonly used to manage chronic UTIs
Chronic UTIs may be managed by treating individual recurrent infection with appropriate antibacterial
Co-trimoxazole may be the drug of choice for chronic prophylaxis

30. prophylaxis
Co-trimoxazole one tablet daily or thrice weekly for 6-12 months depending on the frequency of infection
6 months course may be appropriate for women with < 3 UTIs/year and 12 months in patients with 3 or more UTIs/year
Cephalosporins and fluoroquinolones are reserved for resistant organisms or if the patient is intolerant to or failing prophylaxis with co-trimoxazole