Institute for Microbiology, Medical Faculty of Masaryk University     and St. Anna Faculty Hospital
in Brno
Agents of urinary tract infections

Urinary tract infections (UTIs)
Frequency of UTIs:
The 2nd most common infections (after respiratory ones)
In adults: the most common infections
Afflicting mainly females (because of shorter urethra)




Cystitis
- the most common UTI:
- develops ascendently caused by intestinal microflora
- symptoms:
   dysuria (difficult urination with sharp and burning pain)
pollakisuria (urgent need to urinate accompanied by urination of a small amount of urine only)

Pyelonephritis
- more serious
- origin: ascendent or hematogenous
-  symptoms:
   fever, chills, flank pain, or costovertebral tenderness, urinary frequency, dysuria, hematuria
...urethritis – will be dealt with STD

Etiology of UTIs
Differs in:
•non-complicated UTIs
•infections accompanying structural abnormalities (prostatic hypertrophia, urinary stones,
strictures, pregnancy, congenital defects, permanent catheters)
•infections accompanying  functional disorders (vesicoureteral reflux, neurological disorders,
diabetes mellitus)

Etiology of non-complicated UTIs
1. 80 % Escherichia coli
2. 10 % enterococci (Enterococcus faecalis)
3. 5 % Proteus mirabilis
         - other enterobacteria (Klebsiella pneumoniae,
             Kl. oxytoca, Ent. cloacae, C. freundii etc.)
      - Streptococcus agalactiae
          - coagulase neg. staphylococci
      - yeasts (mainly Candida albicans)







http://biology.clc.uc.edu



Etiology of  complicated UTIs
circa 80 %: Escherichia coli
                 Klebsiella pneumoniae
                 Proteus mirabilis
                    Pseudomonas aeruginosa
                     enterococci
                     other enterobacteria
            acinetobacters
                     other G-neg. non-fermenting rods
           candidae

Lege artis taking a urine sample
•Only after a thorough cleaning of genital incl. external orifficium of urethra by means of soap
and water
•Take the middle stream of urine only
•Use a guaranteed sterile vessel
•Pour it into a sterile tube & stopper promptly
•If not possible to process it within 2 hours, place the specimen into 4 °C for 18 hours at most

http://www.naturalnews.com/cartoons/Expensive_Urine_600.jpg



Semi-quantitative examination of the urine sample – I
We are interested
•not only in the kind of microbe present in the urine sample, but especially
•in the amount of the microbe
Why ?
Because
•high numbers only stand for the UTI
•low numbers mean usually contamination acquired during urination

Semi-quantitative examination of the urine sample – II
Therefore, the urine is inoculated on culture media by a calibrated loop taking 1 μl of urine
In this case
    1 colony means  103 CFU/ml
  10 colonies mean 104 CFU/ml
100 colonies mean 105 CFU/ml
(CFU = colony-forming unit = 1 cell)




Significant concentrations of bacteria in urine
Type of specimen,  symptoms
Type of microbe
Significant number (CFU/ml)
Middle stream, symptoms  present
Primary urine pathogen
103
Dubious urine pathogen
105
Middle stream, no symptoms
Any
105
Suprapubic punction
Any
101

Therapy
•Trimethoprim
•Nitrofurantoin
•Cephalexin
•Amoxicillin
•in complicated UTIs ATB sensitivity assessment
•ESBL strains


Paulus Peeter Rubens (1577-1640): Goddess of health Hygiene (1615)


Detail
Paulus Peeter Rubens (1577-1640): Goddess of health Hygiene (1615)