It has been established that urine is an excellent culture medium for the bacteria.
The purpose of this study is to observe the fate of bacteria in healthy human urine and the rate of bacterial multiplication.
The strains, which were isolated and identified from urine from patients with urinary tract infections, were E. coli, Klebsiella, Cloaca, Citrobacter, Proteus, Morganella, Rettgerella, Staph. aureus, Staph. epidermidis, α-Streptococcus, β-Streptococcus, Enterococcus and Corynebacterium.
The urine, from healthy individuals, was sterilized, and then divided in flasks in 100 ml aliquots. The urine pH and osmolarity were adjusted to 5, 6, 7, 8 and 9 with 0.1 N-HC1 or 10 g/dl Na
2CO
3 and 200, 400, 800 m 0 sm/L with sterile distilled water.
Immediately after addition of bacterial inoculum and again after 4, 8, 12, and 16 hours of incubation at 37°C, aliquots were removed from each specimens for determination of the number of bacteria
The results were as follows:
From the number of bacteria in each specimens after 12 hours incubation, .1) The strains which markedly multiplied at a pH range 6-8 and an osmolarity of 200 mOsm/L-800 mOsm/L were E. coli, Klebsiella, Cloaca, Citrobacter, Proteus, Morganella, Enterococcus, Staph. aureus, and Staph. epidermidis. But β-Streptcoccus did not grow well at the condition of pH 6 and 800 mOsm/L of urine. Corynebaceriumt and a-Streptococcus could not grow in urine under any of those conditions.
2) The growth of most of those strains was slightly inhibited at urine pH 5 and 200 mOsm/L or 400 mOsm/L and all of those, except Pseudomonas, could not grow at 800 mOsm/L.
3) At urine pH 9, E. coli, Proteus, and Morganella multiplied at 200 mOsm/L-800 mOsm/L and Klebsiella, Cloaca, Citrobacter, β-Streptococcus, Enterococcus and Staph. epidermidis multiplied at 200 mOsm/L or 400 mOsm/L, and Pseudomonas multiplied at 400 mOsm/L and 800 mOsm/L.
The results suggested that the multiplication of bacteria in urine depends on the urine pH and osmolaxity. And urine may be a good medium at the condition of pH 6-8 and osmolarity 200 mOsm/L- 800 mOsm/L. But the growth of most of the bacterial strains was inhibited at urine pH. 5 and 9, and this inhibiting activity was in proportion as urine osmolarity decreased.
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