Transfer of Ampicillin resistance from Shigella Dysenterle type 1 to Escherichia Coli

Abstract

We have found that ampicillin resistance in Shigella dysenterice 1 (Shiga bacillus) is mediated by a plasmid. S. dysenterice 1 was endemic in Europe before the 1914-18 war and eventually became replaced by S. flexneri and S. sonnei. In the past, the disease responded to sulphonamides and tetracyclines but the outbreaks in Japan beginning around 1950 were caused by strains containing the multiple drug resistance factor (MDR+); cultures similar to these were found in the regional epidemic in Central America in 1969-71. Characteristically, resistance to sulphonamides, chloramphenicol, tetracycline, and streptomycin is transferable to recipient bacteria by conjugation the R factor being similar to or identical with the plasmid of the chloramphenicol-resistant Salmonella typhi involved in the typhoid epidemic in Mexico.