Bacterial Titer

Bacterial Titer

 

the maximum dilution of an aqueous suspension of bacteria in which the microorganisms can grow. To determine the bacterial titer, a certain amount of the material being examined, such as soil, water, or food, is placed in a test tube with sterile water and thoroughly mixed. Then 1 milliliter (ml) of the solution in the test tube is diluted tenfold in another test tube. Further dilutions are obtained by repeating the operation many times. By culturing samples of different dilutions in selective or differential diagnostic nutrient media intended for the growth of a given physiological group of bacteria, information may be obtained on the quantity of putrefactive, nitrifying, denitrifying, cellulose, and anaerobic bacteria in the material under study. In the testing of water and food for purposes of hygiene and sanitation, the coli index, or titer of colibacillus (Escherichia coli), is of great importance.

A. A. IMSHENETSKII

References in periodicals archive ?
Our results indicate that the produced antibodies against 3-oxo-[C.sub.12]-HSL-r-PcrV significantly decrease bacterial titer in the liver and spleen of the immunized mice in groups II and III compared to the control group.
aeruginosa infection, and concluded that these antibodies did not influence the bacterial titers in internal organs.
Aliquots (100 [micro]L) of serial dilutions of logarithmically growing cultures were plated on trypticase soy agar to determine the bacterial titer. Bacteria of each strain were added to PC samples negative for bacterial contamination to achieve a final concentration of [10.sup.9] colony-forming units (CFU)/L before nucleic acid extraction.
At 0, 5, 10, 15, and 30 minutes, 3 samples of 60 ILl were collected, and the bacterial titer (number of cfu/ml) in these samples was determined by plating 10-fold dilutions on Columbia agar with 5% sheep blood.
After 4 days of treatment, bacterial titers were determined in joint fluid, bone marrow, and bone specimens.
Also, bacterial characterization suggested that it belonged to genotype B, which had bacterial titers 3.2 and 3.89 log 50% lethal dose/ mL, respectively.
All but 1 surviving NL119 P4-infected mice had significant blood bacterial titers ([greater than or equal to] 5 x [10.sup.3] CFU/mL; geometric mean [10.sup.4] CFU/mL).