TY - JOUR
T1 - Increased zinc availability enhances initial aggregation and biofilm formation of Streptococcus pneumoniae
AU - Brown, Lindsey R.
AU - Caulkins, Rachel C.
AU - Schartel, Tyler E.
AU - Rosch, Jason W.
AU - Honsa, Erin S.
AU - Schultz-Cherry, Stacey
AU - Meliopoulos, Victoria A.
AU - Cherry, Sean
AU - Thornton, Justin A.
N1 - Publisher Copyright:
© 2017 Brown, Caulkins, Schartel, Rosch, Honsa, Schultz-Cherry, Meliopoulos, Cherry and Thornton.
PY - 2017/6/7
Y1 - 2017/6/7
N2 - Bacteria growing within biofilms are protected from antibiotics and the immune system. Within these structures, horizontal transfer of genes encoding virulence factors, and promoting antibiotic resistance occurs, making biofilms an extremely important aspect of pneumococcal colonization and persistence. Identifying environmental cues that contribute to the formation of biofilms is critical to understanding pneumococcal colonization and infection. Iron has been shown to be essential for the formation of pneumococcal biofilms; however, the role of other physiologically important metals such as copper, zinc, andmanganese has been largely neglected. In this study, we investigated the effect of metals on pneumococcal aggregation and early biofilm formation. Our results show that biofilms increase as zinc concentrations increase. The effect was found to be zinc-specific, as altering copper and manganese concentrations did not affect biofilm formation. Scanning electron microscopy analysis revealed structural differences between biofilms grown in varying concentrations of zinc. Analysis of biofilmformation in a mutant strain lacking the peroxide-generating enzyme pyruvate oxidase, SpxB, revealed that zinc does not protect against pneumococcal H2O2. Further, analysis of a mutant strain lacking the major autolysin, LytA, indicated the role of zinc as a negative regulator of LytA-dependent autolysis, which could affect biofilm formation. Additionally, analysis of cell-cell aggregation via plating and microscopy revealed that high concentrations of zinc contribute to intercellular interaction of pneumococci. The findings from this study demonstrate that metal availability contributes to the ability of pneumococci to form aggregates and subsequently, biofilms.
AB - Bacteria growing within biofilms are protected from antibiotics and the immune system. Within these structures, horizontal transfer of genes encoding virulence factors, and promoting antibiotic resistance occurs, making biofilms an extremely important aspect of pneumococcal colonization and persistence. Identifying environmental cues that contribute to the formation of biofilms is critical to understanding pneumococcal colonization and infection. Iron has been shown to be essential for the formation of pneumococcal biofilms; however, the role of other physiologically important metals such as copper, zinc, andmanganese has been largely neglected. In this study, we investigated the effect of metals on pneumococcal aggregation and early biofilm formation. Our results show that biofilms increase as zinc concentrations increase. The effect was found to be zinc-specific, as altering copper and manganese concentrations did not affect biofilm formation. Scanning electron microscopy analysis revealed structural differences between biofilms grown in varying concentrations of zinc. Analysis of biofilmformation in a mutant strain lacking the peroxide-generating enzyme pyruvate oxidase, SpxB, revealed that zinc does not protect against pneumococcal H2O2. Further, analysis of a mutant strain lacking the major autolysin, LytA, indicated the role of zinc as a negative regulator of LytA-dependent autolysis, which could affect biofilm formation. Additionally, analysis of cell-cell aggregation via plating and microscopy revealed that high concentrations of zinc contribute to intercellular interaction of pneumococci. The findings from this study demonstrate that metal availability contributes to the ability of pneumococci to form aggregates and subsequently, biofilms.
KW - Biofilms
KW - Cell-cell interactions
KW - Colonization
KW - Pneumococcus
KW - Zinc
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U2 - 10.3389/fcimb.2017.00233
DO - 10.3389/fcimb.2017.00233
M3 - Article
C2 - 28638805
AN - SCOPUS:85027553217
SN - 2235-2988
VL - 7
JO - Frontiers in Cellular and Infection Microbiology
JF - Frontiers in Cellular and Infection Microbiology
IS - JUN
M1 - 233
ER -