J. Mclauchlin et al., SUBTYPING OF LISTERIA-MONOCYTOGENES ON THE BASIS OF PLASMID PROFILES AND ARSENIC AND CADMIUM SUSCEPTIBILITY, Journal of applied microbiology, 83(3), 1997, pp. 381-388
The susceptibilities to arsenic and cadmium together with the detectio
n of plasmid DNA were evaluated for use as epidemiological markers for
the subtyping of Listeria monocytogenes. Plasmid DNA was detected in
34% of 322 apparently unrelated isolates of L. monocytogenes. The resi
stance to cadmium and arsenic differentiated 565 apparently unrelated
cultures into four groups, the smallest being 5% of cultures resistant
to both agents, and the largest (53%) being sensitive to cadmium and
resistant to arsenic. The resistance patterns to these agents and the
presence of plasmid DNA varied markedly between the serotypes of the c
ultures. The detection of plasmid DNA was strongly associated with cad
mium resistance in serogroup 1/2 cultures, but not within those of ser
ogroup 4. Arsenic resistance was not associated with plasmid DNA. All
methods were sufficiently stable to be useful for epidemiological inve
stigations. The techniques described here offer simple methods which c
an be easily utilized in laboratories without a specialized expertise
for this bacterium.