Many clinicians use antibiotics on the patients with severe bacterial infectious diseases to stop process of diseases and for the effective treatments. Combined usage of the antibiotics has been widely used after sulfonamide and penicillin, and many authors have studied about these combined usage of the antibiotics on pathogens and infectious diseases.
In this study we deal with the activity of many antibacterial agents on several pathogens and antibiotic synergisms of antibacterial agents against several group of bacteria, especially gram negative bacilli isolated from clinical specimens. We provide the basic informations for clinicians about the combined usage of antibiotics on infectious diseases. Specimens were isolated from clinical materials at han yang Medical Center during the period of Jan. 1982 to Dec. 1982.
The following results were obtained.
1. Specimens used on this experiment are as following;
15 strains of sal. typhi
3 strains of sal. typhimurium
2 strains of sal. cholerasuis
9 strains of sh. flexneri
4 strains of sh. sonnei
4 strains of sh. boydii
3 strains of sh. dysenteriae
20 strains of K. pneumoniae
20 strains of P.aeruginosa
20 strains of Coliform group
2. Gentamicin produced the best result in M.I.C.(minimal inhibitory concentration) on each pathogen by dilution method. Results of MIC on each pathogen ard as following,
0.12 - 2.0 mcg/ml on Sal. species
0.5 - 100.0 mcg/ml on Sh. species
0.5 - 100.0 mcg/ml on Coliform group
1.0 - 100.0 mcg/ml on K. pneumoniae
1.0 - over 100.0 mcg/ml on P.aeruginosa
3. Results of the drug sensitivity by disk mithod ard as following;
19 Sal. strains sensitive to car benicillin
16 Sh. strains sensitive to amikacin
12 Coliform strsins sensitive to amikacin and 11 to kanamycin
19 K. pneumoniae strains sensitive to amikacin
20 P. aerufinosa strains sensitive to amikacin
4. When we compare the results of dilution method and those of disk method, comparison rate of susceptibility by two methods was 100% on each of thd followinf;
K. pneumoniae by carbenicillin
K. pneumoniae and P. aeruginosa by cephalothin
Sh. species and P. aeruginosa by kanamycin
Sal. species, K. pneumoniae and P. aeruginosa by ampicillin
However it was 85% on Sal. species and 82% on K. pneumoniae by amikacin, and very low (as low as 28-36%) on Coliform group by carbenicllin and cephalothin.
5. The following summary gives the effect of the combined usage of antibacterial agents on several pathogens;
CB/GM and CB/KM combination group excellent on Sal. species
CB/GM combination group excellent on K. pneumoniae
GM/KM combination group excellent on Sh. species and Coliform group
CB/GM and AK/CB combination group excellent on P. aeruginosa
No antagonism was seen on excellent combination group execpt Sh. species and Coliform group.
6. Two strains showed multiple drug resistance patterns on 6 antibacterial agents, 10 strains on 5 antibacterial agents, and 61 strains on above 2 antibacterial agents. K. pneumoniae was the most pathogen showing multiple drug resistance patterns in 20 strains, and the next were P. aeruginosa and Sh. species in 16 strains.
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