[Independence of plasmids harboured in the "Escherichia coli" of patients in hospital without antibiotics (author's transl)].

A study has been carried out of the faeces of nine patients in the same surgical ward. Viable counts and detection of drug resistance were effected by a replica plating method. Bacteria harbouring the drug resistance pattern (ST) were found in seven faeces. Among them, five R plasmids (ST) were transferred to Escherichia coli K12 and have been differentiated by incompatibility studies. As they didn't belong to the same incompatibility group it was concluded that they were not the same incompatibility group it was concluded that they were not the same plasmid acquired in the hospital. One of these R plasmids (ST) was unclassifiable into a known incompatibility group. So, a new incompatibility group, group 12, is proposed.