• YAKHAK HOEJI
• /
• v.52 no.3
• /
• pp.219-224
• /
• 2008

Clinically isolated methicillin-resistant Staphylococcus aureus strains were exposed to subinhibitory concentration of DW286, DW-224a, gemifloxacin, trovafloxacin, sparfloxacin and ciprofloxacin during 26- to 39-days period. Subculturing led to resistance development, and most of the selected mutants were above susceptible breakpoints. Selected mutants had broad cross resistance to other quinolone antibiotics and only one mutant was completely susceptible to all fluoroquinolones. Twenty five among 42 mutants revealed mutations on DNA gyrase and topoisomerase IV by sequencing. Also 16 mutants had fluoroquinolones MICs that were 4-32 times lower in the presence of reserpine. In conclusion, alterations in DNA gyrase or topoisomerase IV and action of efflux pumping out system are the resistance mechanisms of DW-224a.

• Journal of Pharmaceutical Investigation
• /
• v.39 no.6
• /
• pp.431-435
• /
• 2009

The comparative superior in vitro activity of DW-224a was supported by the downward MIC distribution due to the weakened influence of alterations within target enzymes in ciprofloxacin-resistant Staphylococcus aureus. The MI$C_{50}$ for DW-224a was 4 $\mu$g/mL, similar to that of gemifloxacin, 8-fold less than that of sparfloxacin and 16-over-fold less than that of ciprofloxacin. We constructed combinations of amino acid changes, located at codon 80, 83 or 84 within GrlA and 84, 85 or 88 within GyrA, which were associated with MIC increase. The amino acid changes were less influential to the MIC of DW-224a compared to those of other fluoroquinolones, and it was verified from the requirement of a total of two GrlA- and two GyrA-alterations to reach the MIC of DW-224a over 32 $\mu$g/mL.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.11
• /
• pp.1853-1857
• /
• 2008

Salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. A total of 21 isolates of Salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. Among these, 18 isolates were identified as Salmonella enterica serotype Haardt (S. Haardt) and three isolates were S. enterica serotype Muenchen. When the minimal inhibitory concentrations of the S. Haardt isolates were assayed with the agar dilution method to determine susceptibility to ampicillin, chloramphenicol, sulfisoxazole, tetracycline, and nalidixic acid, all 18 isolates were resistant to tetracycline and nalidixic acid and nine of these were resistant to ampicillin. These isolates showed reduced susceptibility to eight fluoroquinolones including ciprofloxacin, enrofloxacin, levofloxacin, gatifloxacin, gemifloxacin, moxifloxacin, norfloxacin, and ofloxacin. When quinolone resistance determining regions of gyrA and gyrB were sequenced, every isolate had the same missense mutation Ser83$\rightarrow$Tyr (TCC$\rightarrow$+TAC) in gyrA, whereas no mutation was found in gyrB. Pulsed-field gel electrophoresis with XbaI revealed a close relationship among these isolates, suggesting a contamination of raw chicken meat with clonal spread of nalidixic acid-resistant and quinolone-reduced susceptibility S. Haardt in chickens. Results in this study show the importance of a well-equipped cold system and the prudent use of fluoroquinolone in chickens to prevent the occurrence of quinolone-resistant isolates.

• The Korean journal of internal medicine
• /
• v.33 no.6
• /
• pp.1203-1209
• /
• 2018

Background/Aims: Adverse drug reaction (ADR) is an appreciably harmful or unpleasant reaction, resulting from an intervention related to the use of a medicinal product. The present study was conducted in order to monitor the frequency and severity of ADR during antimicrobial therapy of septicemia. Methods: A prospective, observational, and noncomparative study was conducted over a period of 6 months on patients of septicemia admitted at a university hospital. Naranjo algorithm scale was used for causality assessment. Severity assessment was done by Hartwig severity scale. Results: ADRs in selected hospitalized patients of septicemia was found to be in 26.5% of the study population. During the study period, 12 ADRs were confirmed occurring in 9, out of 34 admitted patients. Pediatric patients experienced maximum ADRs, 44.4%. Females experienced a significantly higher incidence of ADRs, 66.7%. According to Naranjo's probability scale, 8.3% of ADRs were found to be definite, 58.3% as probable, and 33.3% as possible. A higher proportion of these ADRs, 66.7% were preventable in nature. Severity assessment showed that more than half of ADRs were moderate. Teicoplanin was found to be the commonest antimicrobial agent associated with ADRs, followed by gemifloxacin and ofloxacin. Conclusions: The incidence and severity of ADRs observed in the present study was substantially high indicating the need of extra vigilant during the antimicrobial therapy of septicemia.