Urinary Tract Infection Very common Significant cause of morbidity and mortality. Occurs anywhere between the glomerulus and the external os of the urethra Upper UTI is above the bladder Lower UTI is from the bladder down

Urinary Tract Infection Stages of life : Infancy Preschool Honeymoon cystitis Pregnancy Prostatism

UTI - Who is susceptible? Mostly females due to the (20cm) shorter urethra (30:1). Exceptions are neonatal boys who are 4X more likely than neonatal girls to have an UTI – reasons not clear. Elderly men become more susceptible due to prostatic hyperplasia but never overtake the females (2:1). The one equalising factor is the urethral catheter.

UTI Urinary tract and bladder are normally sterile apart from the anterior urethra which may be colonised with skin flora Presence of microflora alone does not establish significance Pyuria may or may not, reflect a response to infection

Urinary Tract Infection Sterile Pyuria: Renal TB Viral cystitis Glomerulonephritis Prostatitis Urethritis GU Fistula Pelvic Abscess Stones Schistosomiasis

UTI - Frequency and dysuria syndrome Bacterial Cystitis Characterised by significant bacteriuria, pyuria and sometimes haematuria. Abacterial cystitis. Previously known as ‘urethral syndrome’. No bacteria are cultured from urine and the cause is usually unknown. (Often gut and vaginal anaerobes)

UTI Infections are described as ‘uncomplicated’ as in most OPD or GP patients. Or ‘complicated’ eg. in patients with congenital or surgical abnormalities of the tract or those having urological procedures and / or the presence of a urethral catheter.

UTI – Urinary Catheter

Hospital-Acquired UTI Urinary catheter for relief of retention Intermittent catheterisation following head or spinal cord injury, may be required several times a day. Indwelling catheters - continuous drainage may be needed following spinal cord lesion or shorter term post TUR. Any instrumentation or surgery on the urinary tract increases the chances of HA-UTI.

Hospital-Acquired UTI Care and insertion of Urethral Catheter : Motives? Choice of catheter (smallest bore and balloon) Insertion Sterile procedure but NO disinfectant. Bag emptying - maintain closed system. Catheter toilet Urine collection Limit washouts and antibiotics.

UTI Almost all UTI’s are caused by organisms ascending the tract. Few are caused by haematogenous transport of bacteria and other agents - especially M. tuberculosis and Salmonella spp. Also rarely Schisto. haematobium, Histoplasma and viruses such as CMV and Adenovirus

Recognised Urinary Pathogens Mostly Gram-negative bacilli Enterobacteriaceae E. coli Proteus spp Klebsiella spp Enterobacter spp Citrobacter spp Serratia spp Providencia spp

Recognised Urinary Pathogens Other Gram negatives : Pseudomonadaceae Pseudomonas spp Alcaligenes spp Gram-negative coccobacilli Acinetobacter spp

Recognised Urinary Pathogens Gram-positive cocci : Micrococcaceae : Staph saprophyticus Staph aureus Staph. epidermidis Streptococcaceae : Strep faecalis and other enterococci Strep. agalactiae (Lancefield group B) Also yeasts (Candida species)

UTI – Asymptomatic Bacteriuria A significant bacteriuria (>100,000/ml) without symptoms - not treated except for at risk patients: Pregnancy (To prevent acute Pyelonephritis) Renal Disease diabetes or polycystic kidneys The immunocompromised Anatomical or neurological defects Patients about to undergo urological examination Children – require investigation for congenital reflux abnormalities

UTI – Acute Pyelonephritis Predisposing factors : Prostatic enlargement Pregnancy (3rd Trimester) Children with congenital malformations Obstruction, calculi, tumours Urethral catheterisation. Diagnosis as for UTI

UTI – Lab. Diagnosis Specimens are frequently contaminated with normal flora from perineum or genitalia. Contamination reduced by taking ‘midstream urine’ specimens (MSU) having cleaned the genitalia

UTI – Lab. Diagnosis Collection methods : MSU/CSU Adhesive bags Suprapubic stimulation (Babies) Suprapubic aspiration NEVER by catheterisation

UTI – Lab. Diagnosis Must be transported rapidly to lab and refrigerated if delayed. Use of transport kits have been recommended but often inhibitory to organisms

UTI – Lab. Diagnosis Interpretation of results for MSU: 1. >100,000 bacteria/ml urine – UTI 2. 10,000 bacteria/ml urine - usually either contamination or prior antibiotics 1,000 bacteria/ml urine – Usually contamination but may be significant with acute dysuria and frequency More than one organism or mixed growth: Contamination likely

UTI Factors affecting bacterial counts Stage of infection Fluid intake/ frequency of micturition. Presence of antibiotics and other antibacterial substances (eg. Urea) Underlying illness of the patient. Whether patient is post-operative The presence of a urinary catheter Residual urine

UTI Factors affecting bacterial counts cont’d Probably the age and sex of the patient pH of urine The growth rates of the organisms The number of bacteria in a colony forming unit The site of infection

UTI – Lab. Diagnosis White cell count in urine is normally less than 10 white cells / cubic mm of urine. Figures above this suggest an infection. Though the WCC may be raised for other reasons eg : Interstitial neuropathies (diabetes and analgesics) Acute glomerulonephritis Renal failure Neoplasms

UTI – Lab. Diagnosis Reasons for raised WCC cont’d: Postoperative Catheterisation Fevers in children Spread of inflammation of neighbouring sites (eg appendix or bowel) White cells from preputial sac or vagina may contaminate the urine

UTI - Factors predisposing bladder to bacteruria Factors which facilitate ascent of organisms up the urethra : Urethral, bladder or prostatic surgery Sexual intercourse Vaginal prolapse

UTI - Factors predisposing bladder to bacteruria Factors which result in the stagnation of urine in the bladder : Infrequent micturition Inadequate fluid intake (or urinary output) Obstruction (Urethral valves, strictures, prostatic hypertrophy, constipation, calculi and catheters) Vesico-ureteric reflux Impairment of neurogical control of bladder Bladder diverticula

UTI Treatment 1. Increase fluid intake (= urine output) Acidify urine Antibiotics Uncomplicated – 3 days Pyelonephritis – 7 -14 days IV Asymptomatic bacteriuria in pregnancy – 3-7 days