Preliminary epidemiological studies on tetracycline resistant plasmids isolated from enteric bacteria in Nigeria.

In an epidemiological investigation on the genetic determinants responsible for tetracycline resistance in Nigeria, 518 isolates of enteric bacteria from hospitals and clinics were screened for susceptibility to antibiotics. 305 (58.8%) were resistant to tetracycline. The commonest resistance pattern that involved tetracycline resistance was tetr ampr sxtr Smr. Of the 305 isolates, 207 (67.8%) transferred resistant plasmids to Escherichia coli K-12. Altogether, 12 types of plasmids were isolated depending on the phenotypes of antibiotics resistant character borne on the plasmids; they ranged in sizes between 3 to 180 kilobases. The plasmids were evenly distributed in the country. Thus R plasmids are a major reason for resistance to tetracycline encountered in Nigeria.