[Streptococcus pneumoniae growth based on drug resistance genotype].

Marked Streptococcus pneumoniae tolerance is attributed to a penicillin and macrolide resistance genotypes, yet no report has, to our knowledge, compared the ability of these two genotypes to grow. Deviations in the number of clinical appearances of Streptococcus pneumoniae depend on the combination of these genotypes, thought primarily due to the individual strain growth. To test this, we compared ATCC6303 and a strain of each genotype with an absorption spectrophotometer. Time points-T0, T2, T4, T8, T10, T12, and T24-were compared to each of the following factors: initial value, dullness time, doubling time (D.B.T.), peak attainment, peak value, and stationary value. ATCC6303 and the clinical strain (PSSP8) showed no difference in time points or tested factors. Penicillin susceptible Streptcoccus pneumoniae (PSSP) 8 and Penicillin intermediately resistant Streptcoccus pneumoniae (PISP) (2b, mefA) strains showed significant differences in some time pointsT8, T10, and T12-and in certain factors-dullness time, D.B.T., and peak attainment-. In penicillin-resistant genotypes, the sequential growth rate priority was PSSP>PISP>PRSP, while in macrolide-resistant genotypes, it was mefA>non-mefA, and non-ermB>ermB. PISP (2x) and PISP (2x+2b, mefA) begin doubling immediately, suggesting that they proliferate earlier than other strains. Differences in the start of doubling time and doubling speed suggest that different strains are distributed among clinical resistant S. pneumoniae strains.