Forty two strains of Enterobacter isolated from clinical specimens in Taegu area were tested for the antimicrobial suseptibility to 19 drugs and studies for molecular and genetic characterization of R plasmid. 38.1% of the strains were isolated
form
urine and 26.2% from sputum. All strains were susceptible to enoxatin(Ex), norfloxatin(Nf), ciprofloxacin(Cp), ofloxacin(Of) and pefloxacin(Pf).
7. 1-21.4% of the strains were resistant to gentamicin(Gm), amikacin(Ak), nalidixic acid(Na),tetracycline(Tc), and trimethoprim(Tp), 26.2-42.9% to cefamandole(Cfm), kanamycin(Km), streptomycin(Sm), chloramphenicol(Cm) and 47.6-69% to
ampicillin(Ap),
cephalothin(Clt), tobramycin(To).
MIC90 of Ex, Nf, Cp, Of and Pf were below the antimicrobia concentration teste. Most of drug resistances except to Na and Rf in 47% of resistant strains were co-transferred to recipient E. coll RG488 or RG176, indicating that multiple drug
resistance
were R plasmid mediated phenomenon.
Plasmid profiles for molecular characterization of R plasmids from Enterobacter strains were studied through the methods of alkaline SDS lysis and agarose gel electrophoresis. R plasmids were 43.1-83.4 mega dalton in molecular size. EcoR I and
Hind
III
restriction enzyme digestion patterns of R plasmid DNAs were examined. R plasmids that had different molecular weights and phenotype markers showed different restriction patterns. PDE8803 and pDE8810, which have different phenotype marker but
same
molecular weight, showed idntical EcoR I digestion pattern and similar Hind III digestion pattern, so We think these two R plasmids were derived from same source.
|