Comparative Sensitivity of the Echovirus Type 25 JV-4 Prototype Strain and Two Recent Isolates to Glutaraldehyde at Low Concentrations

The sensitivity of two recently isolated antigenic variants of echovirus type 25 (Montpellier 76-1262 and Thionville 86-222) to glutaraldehyde (GTA) at low concentrations was compared with that of the JV-4 prototype strain. The purified viruses were treated under the same conditions with GTA at concentrations ranging from 0.002 to 0.10%. The wild strains exhibited significantly lower sensitivity to GTA than did the prototype strain; with 0.10% GTA, a 2 log10 unit reduction was obtained in 5 min for JV-4 and in 60 and 80 min for Montpellier 76-1262 and Thionville 86-222, respectively. A comparison with previous results obtained with poliovirus type 1 showed that the inactivation rates of echovirus type 25 wild strains were fivefold lower than those of the poliovirus type 1 Sabin strain. The comparative electrophoretic and immunoblot analyses showed differences in the results of GTA binding with capsid proteins of the viruses. Unlike in the poliovirus type 1 Mahoney strain and in the echovirus type 25 JV-4 reference strain, GTA produced only minor intermolecular cross-linkings in the viral particles of the two wild strains of echovirus type 25. Our results suggest that there are both intertypic and intratypic differences in the GTA sensitivities of enterovirus strains. They are of relevance to disinfection procedures in digestive endoscopy and to the choice of the enterovirus strain used for evaluating the efficacy of disinfectants.