Besides the benefit of antimicrobial drugs in control of various infectious diseases, the in-crease of resistant strains and fatal superinfections following the antimicrobial therapy has been an agonizing problem to physicians and scientists. Continuous research and development for more potent new antimicrobial drugs and evaluation of the effectiveness of each antimicrobial drug have been urging problems.
We have already published a paper concerning the susceptibility pattern to 14 currently used antimicrobial drugs of E. coli isolated from a doctorless area and a hospital in Korea.
As a successive study, in summer 1976, 25 strains of Enterobacter spp. were isolated from the stool of dwellers in Socho-Myun, Weonseong-Kun, Kangween-Do, Korea which was a doctorless area(abbreviated as local strains).
From Sept. 1975 to Feb. 1976, 21 strains of Enterobacter spp. were isolated from the specimens in the Clinical Laboratory of Seoul National University Hospital(abbreviated as hospital strains).
Their susceptibility to 14 antimicrobial drugs were measured by the agar dilution method.
The results were summarized as follows:
1. With Kanamycin, Streptomycin, Tetracycline, Oxytetracycline, Minocycline, Doxycycline and Cotrimoxazole, the MIC´s of hospital strains were 6. 1, 3. 7, 7, 4. 9, 2. 2.6 and 1.6 times higher than those of local strains respectively.
On the other hand, no significant differences in susceptibilities could be found between the local strains and the hospital strains with Ampicillin, Gentamicin, Troleandomycin, Erythromycin, Penicillin, Carbenicillin and Cephalexin respectively.
2. The most potent agent to 46 strains of Enterobacter spp. isolated from both area was Cotrimoxazole, followed by Gentamicin, Kanamycin and Streptomycin.
3. Frequency of resistant strains was the highest with Troleandomycin (100%`), and decreased in the following order; Erythromycin(78.3%), Penicillin(54.3 0), Carbenicillin,41 3%), Ampicillin(39.1%) Tetracycline(21.7%), OxytetracyclineC21.7% , Streptomycin(17.40), Cephalexin
<15.2%), Kanamycin(15.2%), Doxycycline(13.0i6), Gentamicin(4.4%), Minocychne(2.25%) .and Cotrimoxazole(0/0.
4. Frequency of resistant strains in hospital Enterobacter was higher than that in local -Enterobacter with Kanamycin, Streptomycin, Tetracycline, Oxytetracycline and Doxycycline.
No significant differences in frequency of resistant strains could be found between two groups .of Enterobacter with Gentamicin, Ampicillin, Cotrimoxazole, 111inocycline, Troleandomycin, Erythromycin, Penicillin, Carbenicillin and Cephalexin.
5. Local strains were resistant to less than 7 antimicrobials, while hospital strains showed wider range of multiple resistance, i.e. 61.9% of the hospital strains were resistant to less than
antimicrobials and 38.1% of them showed multiple resistance to from 7 to 12 antimicrobials.
6. 4 Tetracycline analogues revealed high degree of relatedness in susceptibility which the 46 strains of Enterobacter showed to the agents, with high correlation coefficientsi0.800.91 .among them.
Correlation coefficients between Doxycycline and 3 aminoglyosides ranged from 0.70 to 0.-~. Correlation coefficients between Penicillin and Ampicillin and between_ Penicillin and 4 Tetracycline analogues ranged from 0.51 to 0.58.
Correlation coefficients among the 3 aminoglycosides ranged from 0. 58 to 0. 72.
Correlation coefficients between Streptorrvcin and 4 Tetracycline analogues ranged from 0.-) to 0.78.
|