STUDIES ON URINARY TRACT INFECTIONS (REPORT II)
1966 Volume 57 Issue 3 Pages 236-249
Details
1966 Volume 57 Issue 3 Pages 236-249
Quantitative bacterial counts of the urine were carried out by a following surface streaked plate technique method.
With a sterile pipet, 0.1ml. of serially diluted, unsedimented urine was transferred onto the surface of well-dried blood agar.
The urine was then evenly streaked out over the surface of the plate with a sterile L-shaped platinum loop. The results of the investigation were shown as follows.
1) Bacterial counts performed upon 64 urinary specimens were found to exhibit a good degree of correlation with those obtained by means of the standard dilution pour plate method.
Advantages of the plate method became apparent. Organisms could be counted its discrete colonies separately in the case of mixed infections and colonies could be picked up quickly from mixed cultures after 24 hours for final indentification and drug resistance studies.
2) When refrigerated at temperature of 4°C, variation of urinary PH had a considerable influence upon the bacterial counts of urine specimens.
3) Seventy-three patients with no clinical evidence of urinary tract infections were found to contain less than 100, 000 bacteria per ml. in their urine.
In the patients with symptoms generally recognized as those of urinary tract infections, there were two separate but overlapping population groups.
Among 48 untreated patients, 62.6 per cent were found to have more than 100, 000 bacteria per ml. of urine. Conversely, 67.6 per cent of 53 treated patients were found usually to have less than 100, 000 bacteria per ml. Criteria of infection should be decided when several successive daily specimens of urine contained fixed bacteria.
4) The growth of bacteria was inhibited by antibacterial agents and urinary PH. Also, dilution and vesical emptying (voiding) reduced bacterial counts.
5) The gram stain of the freshly collected and sedimented urine will differentiate contamination from infection, since gramstained smears of centrifuged urines were positive in 90 per cent of counts of 100, 000 and in. 182 per cent of counts between 1, 000 and 100, 000.
