TY - JOUR
T1 - Bacterial aggregate size determines phagocytosis efficiency of polymorphonuclear leukocytes
AU - Alhede, Maria
AU - Lorenz, Melanie
AU - Fritz, Blaine Gabriel
AU - Jensen, Peter Østrup
AU - Ring, Hans Christian
AU - Bay, Lene
AU - Bjarnsholt, Thomas
PY - 2020
Y1 - 2020
N2 - The ability of bacteria to aggregate and form biofilms impairs phagocytosis by polymorphonuclear leukocytes (PMNs). The aim of this study was to examine if the size of aggregates is critical for successful phagocytosis and how bacterial biofilms evade phagocytosis. We investigated the live interaction between PMNs and Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Staphylococcus epidermidis using confocal scanning laser microscopy. Aggregate size significantly affected phagocytosis outcome and larger aggregates were less likely to be phagocytized. Aggregates of S. epidermidis were also less likely to be phagocytized than equally-sized aggregates of the other three species. We found that only aggregates of approx. 5 μm diameter or smaller were consistently phagocytosed. We demonstrate that planktonic and aggregated cells of all four species significantly reduced the viability of PMNs after 4 h of incubation. Our results indicate that larger bacterial aggregates are less likely to be phagocytosed by PMNs and we propose that, if the aggregates become too large, circulating PMNs may not be able to phagocytose them quickly enough, which may lead to chronic infection.
AB - The ability of bacteria to aggregate and form biofilms impairs phagocytosis by polymorphonuclear leukocytes (PMNs). The aim of this study was to examine if the size of aggregates is critical for successful phagocytosis and how bacterial biofilms evade phagocytosis. We investigated the live interaction between PMNs and Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Staphylococcus epidermidis using confocal scanning laser microscopy. Aggregate size significantly affected phagocytosis outcome and larger aggregates were less likely to be phagocytized. Aggregates of S. epidermidis were also less likely to be phagocytized than equally-sized aggregates of the other three species. We found that only aggregates of approx. 5 μm diameter or smaller were consistently phagocytosed. We demonstrate that planktonic and aggregated cells of all four species significantly reduced the viability of PMNs after 4 h of incubation. Our results indicate that larger bacterial aggregates are less likely to be phagocytosed by PMNs and we propose that, if the aggregates become too large, circulating PMNs may not be able to phagocytose them quickly enough, which may lead to chronic infection.
KW - Chronic bacterial infection
KW - E. coli
KW - P. aeruginosa
KW - Phagocytosis
KW - Polymorphonuclear leukocytes (PMNs)
KW - S. aureus
KW - S. epidermidis
U2 - 10.1007/s00430-020-00691-1
DO - 10.1007/s00430-020-00691-1
M3 - Journal article
C2 - 32880037
AN - SCOPUS:85090088733
VL - 209
SP - 669
EP - 680
JO - Zeitschrift fur medizinische Mikrobiologie und Immunologie
JF - Zeitschrift fur medizinische Mikrobiologie und Immunologie
SN - 0300-8584
ER -