The epidemiology of Escherichia coli strains isolated from newborn infants in the hospital was studied by using plasmid analysis, restriction endonuclease analysis, and incompatibility grouping of conjugative R plasmid in conjunction with
biotyping
and
antibiogram patern.
Nineteen of 20 E. coli isolates from 12 infants were resistant to antimicrobial drugs and 16 strains carried conjugative R plasmids.
By incompatibility grouping, 7 conjugative R plasmids resistant to streptomycin(Sm), sulisoxazole(Su), ampicillin(Ap), and kanamycin(Km), were classified into IncIa, 1 plasmid resistant to chloramphenicol and tetracycline, and the remaining 11
were
untypable.
Seven IncIa plasmids with 77 megadalton which were obtained from strains with identical plasmid profile, antibiogram, and biotype showed identical fragment pattern generated by restriction endonuclease EcoRI and HindⅢ.
Untypable R plasmids which derived from 3 infants and resistant to tetracyclinec(Tc)Sm, TcAp, Sm, or Ap also showed identical molecular size and fragment pattern one another.
But 2 plasmids resistant to ApKm showed quite different pattern. These results suggested that newborn infants in hospital carried common fecal E. coli exhibiting multiresistance derived from the hospital environments and there seemed to be
exchange
of
fecal E. coli harboring R plasmids among hospitalized infants.
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