Specific gyrA Mutation at Codon 83 in Nalidixic Acid-Resistant Salmonella enterica Serovar Typhi Strains Isolated from Vietnamese Patients

Abstract
Typhoid fever is commonly seen in the developing countries, and the acquired resistance of Salmonella enterica serovar Typhi to antibiotics is a serious problem for the treatment of this disease. Before 1993, no nalidixic acid (NAL)-resistant strain was found in Vietnam. Since then, however, NAL- as