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Center for Biofilm Engineering
Abstract:
"Growth Limitation of Staphylococcus epidermidis in Biofilms
Contributes to Rifampin Tolerance"
04-009 Tolerance of Staphylococcus epidermidis in biofilms to killing
by rifampin was correlated with limitation of bacterial growth in the biofilm
state. Intact biofilm experienced a 0.62 log reduction when treated with 0.1 [mu]g
rifampin/ml for 4 h whereas the same treatment of exponential-phase planktonic
cells produced a log reduction of 4.48. Stationary-phase planktonic cells were
nearly as tolerant as intact biofilm cells, experiencing a 1.11 log reduction.
Biofilm bacteria grew at only 10% of the maximum rate at which they grew on the
same medium in planktonic culture. Killing was localized near the surface of the
biofilm adjacent to the nutrient source, as revealed by staining with a
respiratory dye. Increased nutrient concentration during antibiotic treatment
enhanced killing of biofilm cells. Changing the oxygen tension in the gas phase
above the biofilm during antibiotic treatment barely affected killing. It was
hypothesized that the biofilm harbors significant numbers of
stationary-phase-like cells in the nutrient-limited depths of the biofilm, and
that these inactive cells are the ones that survive antibiotic challenge.
Zheng, Z. and P.S. Stewart, "Growth Limitation of Staphylococcus epidermidis
in Biofilms Contributes to Rifampin Tolerance" Biofilms 1(1):31-35 (2004) |
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