[The choice of the method for determining the potential pathogenicity of shigellae]

The biological characteristics of 196 Shigella strains, isolated in regions with different levels of the geomagnetic field tension, were under study. Strains able to adsorb Congo red, characterized by antilysozyme activity, hydrophobic, resistant to gentamycin, monomycin, kanamycin, rifampicin were more frequently isolated in the regions with a higher tension of the field, this being confirmed by a stable correlation. The ability of Shigellae to fix Congo red correlated with the before signs and with colicinogenicity, therefore this test may be recommended for the assessment of Shigella virulence.