Drug resistance and plasmid profile of Shigella organisms from different outbreaks in Trinidad and Tobago in 1994.

The plasmid profiles of 16 Shigella species isolated from cases of bacillary dysentery from different areas of Trinidad and Tobago during one calendar year, and their resistance pattern to eight antibiotics were analysed. All isolates except one S. sonneistrain, were multiple resistant. Two strains (both S. sonnei) had nine plasmid bands which were the maximum found. There were several plasmid bands common among resistant strains with multiple or single resistant profiles. Resistance to ampicillin and sulphonamide were the most common (93.8%), followed by trimethroprim (25.0%), and tetracycline (6.25%). The results indicate that the outbreaks may not be related.