PMID: 10788366May 2, 2000Paper

Cell wall chemical composition of Enterococcus faecalis in the viable but nonculturable state

Applied and Environmental Microbiology
C SignorettoP Canepari

Abstract

The viable but nonculturable (VBNC) state is a survival mechanism adopted by many bacteria (including those of medical interest) when exposed to adverse environmental conditions. In this state bacteria lose the ability to grow in bacteriological media but maintain viability and pathogenicity and sometimes are able to revert to regular division upon restoration of normal growth conditions. The aim of this work was to analyze the biochemical composition of the cell wall of Enterococcus faecalis in the VBNC state in comparison with exponentially growing and stationary cells. VBNC enterococcal cells appeared as slightly elongated and were endowed with a wall more resistant to mechanical disruption than dividing cells. Analysis of the peptidoglycan chemical composition showed an increase in total cross-linking, which rose from 39% in growing cells to 48% in VBNC cells. This increase was detected in oligomers of a higher order than dimers, such as trimers (24% increase), tetramers (37% increase), pentamers (65% increase), and higher oligomers (95% increase). Changes were also observed in penicillin binding proteins (PBPs), the enzymes involved in the terminal stages of peptidoglycan assembly, with PBPs 5 and 1 being prevalent, and in...Continue Reading

Related Concepts

LTA-2
Bacterial Proteins
Muramoylpentapeptide Carboxypeptidase
Carrier Proteins
Cell Wall
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Lipopolysaccharides
Leftose
Oligopeptides

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