a search method in a biological sample containing an hiv 2 viral strain for possible resistance of said strain to treatment by an anti - protease agent , and nucleotide probes for the implementation thereof . according to methods known per se , the presence of at least one mutation at certain , specified , particular positions of the proteinic sequence of the protease of said viral strain from a biological sample taken from a patient contaminated by hiv 2 is searched . if said mutation is observed , the existence of a resistance to said anti - protease agent is assumed in the patient .