An investigation of the spread of gentamicin resistance in a district general hospital.

A cluster of infections caused by gentamicin-resistant gram-negative bacilli in a District General Hospital was investigated. The plasmids coding for gentamicin resistance in the infecting organisms and in isolates obtained from the ward environment and from the faeces of patients and staff were characterised. Six plasmids encoding gentamicin resistance were recognised amongst the organisms causing infection. Two of the plasmids were found in different serotypes of the same species and one plasmid was found in different genera. Three of the plasmids present in the organisms causing the infections were also present in the inanimate environment or in the bowel flora of patients and these also were found in different serotypes of the same species and in different genera.