Chromosome replication as a measure of bacterial growth rate during Escherichia coli infection in the mouse peritonitis model

TY - JOUR

T1 - Chromosome replication as a measure of bacterial growth rate during Escherichia coli infection in the mouse peritonitis model

AU - Haugan, Maria Schei

AU - Charbon, Godefroid

AU - Frimodt-Møller, Niels

AU - Løbner-Olesen, Anders

PY - 2018/12/1

Y1 - 2018/12/1

N2 - The efficacy of most antibiotics is dependent on active bacterial growth, yet little is known about the growth dynamics during infection. Therefore, means to measure in-host bacterial growth rate is of importance. Here, we use chromosome replication as readout for in situ bacterial growth rate during infection; obtained from a single biological specimen. We have applied two independent methods: quantitative PCR (qPCR) and fluorescence microscopy, to quantify the level of chromosome replication present during Escherichia coli propagation in the mouse peritonitis model. We find that the methods complement each other and allow for quantification of growth rate, both on a population average and on a single-cell level. We demonstrate the presence of heterogeneous growth rates within bacterial populations propagating during infection. Also, no growth cessation was observed during the apparent stationary phase in vivo, and, by comparison of growth dynamics at different anatomical sites, we demonstrate that E. coli is unlikely to grow independently intravascularly. These findings provide novel insight into bacterial growth during host infection, and underscore the importance of pinpointing the primary site of infection in septicaemia of unknown origin and ensuring antibiotic availability at this site.

AB - The efficacy of most antibiotics is dependent on active bacterial growth, yet little is known about the growth dynamics during infection. Therefore, means to measure in-host bacterial growth rate is of importance. Here, we use chromosome replication as readout for in situ bacterial growth rate during infection; obtained from a single biological specimen. We have applied two independent methods: quantitative PCR (qPCR) and fluorescence microscopy, to quantify the level of chromosome replication present during Escherichia coli propagation in the mouse peritonitis model. We find that the methods complement each other and allow for quantification of growth rate, both on a population average and on a single-cell level. We demonstrate the presence of heterogeneous growth rates within bacterial populations propagating during infection. Also, no growth cessation was observed during the apparent stationary phase in vivo, and, by comparison of growth dynamics at different anatomical sites, we demonstrate that E. coli is unlikely to grow independently intravascularly. These findings provide novel insight into bacterial growth during host infection, and underscore the importance of pinpointing the primary site of infection in septicaemia of unknown origin and ensuring antibiotic availability at this site.

U2 - 10.1038/s41598-018-33264-7

DO - 10.1038/s41598-018-33264-7

M3 - Journal article

C2 - 30297723

SN - 2045-2322

VL - 8

SP - 1

EP - 13

JO - Scientific Reports

JF - Scientific Reports

M1 - 14961

ER -