Infection dynamics of <i>Brucella</i> spp. in human macrophages and HeLa cells.

<p>THP-1 cells (A) and HeLa S3 cells (B) were challenged with <i>B. pinnipedialis</i> HS (B17), <i>B. pinnipedialis</i> reference strain (12890; harbor seal) and <i>B. suis</i> 1330 (only THP-1 cells) in a gentamicin protection assay. Both <i>B. pinnipedialis</i> strains tested entered in similar numbers in the respective cell types. None of the marine mammal <i>Brucella</i> strains were able to multiply within 48 h pi, as observed for <i>B. suis</i> 1330. At 72 and 96 h pi, slightly higher numbers of bacteria could be retrieved from certain wells, most pronounced with the reference strain (12890) in HeLa cells, but none reached the initial numbers at 1.5 h pi. Error bars correspond to the standard error. Each indicator represents the mean of four (<i>B. suis</i> 1330), six (12890) or nine (B17) replicate wells from 2 or 3 separate assays in A, and six replicate wells from 2 separate assays (B17 and 12890) in B. * (different from 12890, <i>p</i> < 0.05).