Hemolytic activity reevaluation of putative nonpathogenic Listeria monocytogenes strains.
Identification of 12 strains originally characterized as nonpathogenic Listeria monocytogenes was reassured following the evaluation of their hemolytic capability with a newly developed horse blood agar plate. Seven of the strains were observed consistently to be hemolytic and confirmed as L. monocytogenes with the use of two commercial systems: the Gene-Trak L. monocytogenes-specific colorimetric DNA hybridization assay and the API Listeria system. Except for one strain that formed typical smooth colonies, these hemolytic strains formed rough colonies on a selective medium, lithium chloride-ceftazidime agar. The rest of the strains were nonhemolytic and did not hybridize with the DNA probe; they were identified as Listeria innocua on the basis of their API Listeria system biochemical profile. All but one of these nonhemolytic strains formed smooth colonies on lithium chloride-ceftazidime agar.
Lachica
R V
RV
U.S. Army Solider Systems Command, Natick Research, Development, and Engineering Center, Massachusetts 01760, USA.
D000362:Agar; D000818:Animals; D015373:Bacterial Typing Techniques; D001431:Bacteriological Techniques; D001769:Blood; D015342:DNA Probes; D006461:Hemolysis; D006736:Horses; D006801:Humans; D066298:In Vitro Techniques; D008087:Listeria / Q000145:classification / Q000235:genetics / Q000472:pathogenicity; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D013045:Species Specificity; D014774:Virulence
D015342:DNA Probes; D000362:Agar