[Use of genetic and molecular characteristics of R plasmids as an epidemiological marker in an outbreak of hospital infection].

Antibiotic sensitivity of 38 strains of enteric bacteria, such as Serratia marcescens Klebsiella pneumoniae and others and Ps. aeruginosa isolated during an outbreak of meningitis in a premature infant resuscitation department was studied. It was shown that all the isolates were multiple resistant, most frequently to 7 antibiotics. All the resistance markers were transferred on conjugation, segregation of some markers being observed. Investigation of the plasmid composition of the clinical strains and transconjugants of E. coli revaled the presence of 2 plasmids with the molecular weights of 40 and 60 Md or one of them. The restriction analysis demonstrated that the plasmids with the same molecular weights isolated from different strains were identical. It was suggested that such plasmids originated from the same source and were distributed by conjugation. The possible part of R plasmids in epidemiological analysis of hospital infections is discussed: the possible part as an additional marker in determination of the infection source and the possible part through its ability to change the host cell phenotype, including the phage and bacteriocin types.