Development and evaluation of a biochemical scheme for identification of endocervical lactobacilli

A biochemical scheme for the species identification of endocervical lactobacilli was developed and evaluated with 10 isolates obtained from the American Type Culture Collection (ATCC) and 106 endocervical isolates obtained from women reporting to a local venereal disease clinic and a local hospital clinic. The scheme consisted of two stages. Stage I included six tests and was tested and modified with results obtained with ATCC strains. From the modified stage I, stage II was developed. Tests to be performed in this stage were determined from expected characteristics of lactobacilli. Stage II was also tested with the ATCC strains. Of the 106 endocervical isolates, 78 (74%) were identified with the two-stage scheme as developed with the ATCC strains. Unexpected results were obtained in one or both stages with the other 28 isolates. For 10 isolates, the final species identified were not previously expected to be recovered. A "best-fit" method was used to determine the most likely identification of the remaining 18 isolates. In a few instances, the use of a third stage was necessary to reach an identification. The final identification scheme, although complicated in appearance, generated a species identification with a total of 12 tests with a range of 7 to 10 tests per isolate.