• YAKHAK HOEJI
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• v.40 no.3
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• pp.347-350
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• 1996

The post-antibiotic effect (PAE), which is defined as the period of time lag that the target organisms resume normal growth rate after complete removal of the antibiotics, of LB 20304 and ciprofloxacin was evaluated against Staphylococcus aureus 6538p and Escherichia coli 3190Y, respectively. The PAE was estimated by adding each antibiotic to a log phase of growth and incubating at $37^{\circ}$C for 1 h.Antibiotic was removed by centrifugation, and total viable cell counts were determined hourly for a further 10 h. The PAEs of LB20304 against S. aureus at concentrations of $1{\times}MIC\;and\;2{\mu}g/ml$ were 10 min and 93min, respectively. LB20304 showed a comparable PAE to ciprofloxacin. Against E. coli, the PAE of LB20304 was also similar to that of ciprofloxacin at concentration of $4{\times}MIC$ but it was much longer than that of ciprofloxacin at concentration of 2${\mu}g/ml$. LB20304 showed higher lethality than ciprofloxacin against both S. aureus and E. coli strains.

• YAKHAK HOEJI
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• v.42 no.2
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• pp.229-231
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• 1998

The post-antibiotic effects (PAE) of DW-116 were evaluated against Bacillus subtilis ATCC 6633, Bacillus cereus ATCC 27348, Staphylococcus aureus ATCC 25923 , Escherichia coli ATCC 25922 and Pseudomonas aeruginosa MB4-16, repectively. Against gram-positive bacteria, PAEs of DW-116 were longer duration (20-35 min) than those of rufloxacin(1O-20 min), and shorter than those of ciprofloxacin (50-90 min). Especially, against E. coli, DW-116 and ciprofloxacin obtained approximately 3 hrs of PAES.

• Biomolecules & Therapeutics
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• v.5 no.2
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• pp.187-193
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• 1997

The in vivo and in vivo antibacterial activity of DW-116, a newly synthesized fluoroquinolone, were compared with those of other quinolones. DW-116 exhibited more potent antibacterial activity than rufloxacin and lower activity than ofloxacin and ciprofloxacin in in vivo assay But, DW-116 particularly showed strong activity against the family of staphylococci including methicillin-sensitive staphylococcus and its activity was more active than that of ciprofloxacin. The time-kill curve studies showed rapid bactericidal activity for DW-116. The post-antibiotic effect of DW-116 was observed between 0.66 and 5 hours. The therapeutic efficacy of DW-116 against respiratory infection with P. aeruginosa was as strong as that of ciprofloxacin and its effect against urinary tract in(traction with E. coli was more effective than rufloxacin. The excellent therapeutic efficacy of DW-116 against these local infections is due to its good pharmacokinetic profiles.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.152-161
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• 2014

The in vitro antimicrobial potential of the unexplored Moringa oleifera seed coat (SC) was evaluated against some Gram-positive and Gram-negative bacteria and yeast pathogens. Antimicrobial studies with various solvent extracts indicated ethyl acetate to be the best extractant, which was used for the rest of the antimicrobial studies as it tested neither toxic nor mutagenic. Gram-positive bacteria including a methicillin resistant Staphylococcus aureus (MRSA) strain were more susceptible with a minimum inhibitory concentration (MIC) range of 0.03-0.04 mg/ml. The antimicrobial pharmacodynamics of the extract exhibited both concentration-dependent and time-dependent killing. Most of the test organisms exhibited a short post antibiotic effect (PAE) except Enterococcus faecalis, Staphylococcus aureus, and Klebsiella pneumoniae 1, which exhibited longer PAEs. Amongst the major phytoconstituents established, flavonoids, diterpenes, triterpenes and cardiac glycosides exhibited inhibitory properties against most of the test organisms. The identified active phytochemicals of the M. oleifera seed coat exhibited antimicrobial potential against a wide range of medically important pathogens including the multidrug-resistant bugs. Hence, the M. oleifera seed coat, which is usually regarded as an agri-residue, could be a source of potential candidates for the development of drugs or drug leads of broad spectrum that includes multidrug-resistant bugs, which are one of the greatest concerns of the $21^{st}$ century.

• Journal of Veterinary Science
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• v.22 no.6
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• pp.41.1-41.14
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• 2021

Background: Our previously prepared ceftiofur (CEF) hydrochloride oily suspension shows potential wide applications for controlling swine Streptococcus suis infections, while the irrational dose has not been formulated. Objectives: The rational dose regimens of CEF oily suspension against S. suis were systematically studied using a pharmacokinetic-pharmacodynamic model method. Methods: The healthy and infected pigs were intramuscularly administered CEF hydrochloride oily suspension at a single dose of 5 mg/kg, and then the plasma and pulmonary epithelial lining fluid (PELF) were collected at different times. The minimum inhibitory concentration (MIC), minimal bactericidal concentration, mutant prevention concentration (MPC), post-antibiotic effect (PAE), and time-killing curves were determined. Subsequently, the area under the curve by the MIC (AUC_0-24h/MIC) values of desfuroylceftiofur (DFC) in the PELF was obtained by integrating in vivo pharmacokinetic data of the infected pigs and ex vivo pharmacodynamic data using the sigmoid E_max (Hill) equation. The dose was calculated based on the AUC_0-24h/MIC values for bacteriostatic action, bactericidal action, and bacterial elimination. Results: The peak concentration, the area under the concentration-time curve, and the time to peak for PELF's DFC were 24.76 ± 0.92 ㎍/mL, 811.99 ± 54.70 ㎍·h/mL, and 8.00 h in healthy pigs, and 33.04 ± 0.99 ㎍/mL, 735.85 ± 26.20 ㎍·h/mL, and 8.00 h in infected pigs, respectively. The MIC of PELF's DFC against S. suis strain was 0.25 ㎍/mL. There was strong concentration-dependent activity as determined by MPC, PAE, and the time-killing curves. The AUC_0-24h/MIC values of PELF's DFC for bacteriostatic activity, bactericidal activity, and virtual eradication of bacteria were 6.54 h, 9.69 h, and 11.49 h, respectively. Thus, a dosage regimen of 1.94 mg/kg every 72 h could be sufficient to reach bactericidal activity. Conclusions: A rational dosage regimen was recommended, and it could assist in increasing the treatment effectiveness of CEF hydrochloride oily suspension against S. Suis infections.