• Korean Journal of Microbiology
• /
• v.45 no.2
• /
• pp.99-104
• /
• 2009

This study describes the antimicrobial susceptibility and multidrug resistance patterns in 115 isolates of Salmonella enterica serovar Enteritidis from diarrhea patients in Incheon from Jan. 2004 to Dec. 2008. Overall, the highest rate of resistance was found to the following antimicrobial agents: nalidixic acid 54.8%, ampicillin 40.0%, ticarcillin 38.3%, chloramphenicol 20.9%, and tetracycline 17.4%. 91% (104 isolates) were resistant to one or more antimicrobial agents tested. Among the described antimicrobial resistant patterns, the predominant patterns were only nalidixic acid (44.3%), ampicillin-chloramphenicol-ticarcillin (11.3%,) and ampicillin-ticarcillin (10.4%). Overall, the resistant rate to one drug was 51.9%, two drugs 18.2%, three drugs 14.5%, four drugs 5.8%, and five or more drugs 9.7%.

• Korean Journal of Clinical Laboratory Science
• /
• v.49 no.4
• /
• pp.427-434
• /
• 2017

Species that belong to the Acinetobacter calcoaceticus-baumannii (Acb) complex are major causes of hospital-acquired infections. They are important opportunistic pathogens. These species are usually multidrug resistant (MDR), and the therapeutic options to treat the infections caused by these species are limited. In the present study, we investigated fluoroquinolone resistance mechanisms in 53 ciprofloxacin resistant Acinetobacter species isolates in Chungcheong, Korea. Antimicrobial susceptibilities were determined using the disk-diffusion method. Detections of genes and identification of mutations associated with fluoroquinolone resistance were carried out using PCR and DNA sequencing. In our study, 47 out of 53 ciprofloxacin resistant Acinetobacter isolates harbored sense mutations at the 83rd residue (serine to leucine) in the gyrA gene as well as at the 80th residue (serine to leucine) in the parC gene. Among the 47 isolates harboring sense mutations in gyrA and parC gene, 44 isolates were A. baumannii and 3 isolates were A. pittii. Plasmid-mediated quinolone resistance (PMQR) determinants were detected in isolates in our study. Among the 46 ciprofloxacin resistant A. baumannii isolates, 41 showed type A, B, or F banding patterns on their REP-PCR profiles. This result suggests that clonal relation and horizontal spreading of the bacterial isolates have been around hospitals in Chungcheong area. To prevent colonization and disseminations of fluoroquinolone resistance Acb complex isolates, continuous investigation and monitoring of antimicrobial resistant determinants of MDR isolates are needed.

• Journal of fish pathology
• /
• v.7 no.1
• /
• pp.37-46
• /
• 1994

A total 103 strains of Edwardsiella tarda was isolated from eel culture-ponds and examined for drug resistance, distribution and transferabilities of R plasmids. The drugs used were lincomycin(LM), penicillin(PM), sulfamethazine(SF), sulfadimethoxine(SD), cephalosprin(CP), chloramphenicol(CH), streptomycin(SM), oxytetracycline(OT), ampicillin(AP), oxolinic acid(OA), kanamycin(KM), amikacin(AK), gentamicin(GM) and enrofloxacin(EF). Two strains were resistant to the all drugs used, and all isolates were multiply resistant to drugs(at least 8 among 14 drugs), mostly restricted to LM(103 strains), PM(103 strains), SD(103 strains), SF(103 strains), CP(102 strains), CM(101 strains), SM(100 strains), OT(94 strains), AM(92 strains), OA(80 strains), KM(60 strains), AK(30 strains), GM(19 strains) and EF(14 strains), in combination at high degree showing 34 different drug resistant patterns. The most frequently encountered patterns were LM PM SD SF CP CH SM OT AP OA KM(22 strains, 22.4%) followed by LM PM SD SF CP CH SM OT AP OT(12 strains, 11.7%). LM PM SD SF CP CH SM OT AP(7 strains, 6.8%), LM PM SD SF CP CH SM OT AP OA KM AK GM(6 strains, 5.8%) and LM PM SD SF CP CH SM OT AM OX KM AK GM(6 strains, 5.8%). Transfer experiment of drug resistance showed that of 103 resistant strains, 100 strains(97%) transferred part or all resistance to all drugs, indicating that most isolates carried conjugally transferrable R plasmids determining multiple drugs. The most frequently observed transferarble R plasmids were LM PM SD SF CP CH SM OT AP OA(10 strains), LM PM SD SF CP CH SM OT AP OX KM(7 strains) and LM PM SD SF CP CH AP OA(7 strains). These results sugested that eel culture-ponds were highly contaminated with different strains of Edwardsiella tarda, and that contaminated bacteria might be highly multiple resistant strains to drugs, carring transferable R plasmids.

• Microbiology and Biotechnology Letters
• /
• v.38 no.1
• /
• pp.77-83
• /
• 2010

The fructus of Crataegus pinnatifida Bunge (CBF) has been used as medicinal and food source in worldwide. In this study, antimicrobial activity of the methanol extract and its sequential organic solvent fractions of CBF against different pathogenic bacteria and fungi, including multidrug resistant Pseudomonas aeruginosa and Candida sp., were investigated. The methanol extract of CBF was active against various gram-positive and gram-negative bacteria, and the ethylacetate and butanol fractions of CBF showed strong antibacterial activity against Listeria monocytogenes, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Proteus vulgaris, Escherichia coli and various multidrug resistant Pseudomonas aeruginosa with minimal inhibitory concentration of 1.0~7.5 mg/mL. Also the fractions showed anti-Candida activity against C. albicans, C. kruseis and C. geochares. The methanol extract of CBF and its solvent fractions, except n-hexane fraction, did not show any hemolytic activity against human red blood cell up to $500\;{\mu}g/mL$, respectively. The hemolysis in n-hexane fraction at $500\;{\mu}g/mL$ was less than 9.9%. Our results suggest that the CBF could be developed as a potent antibacterial agent, especially for multidrug resistant Pseudomonas aeruginosa.

• Korean Journal of Microbiology
• /
• v.46 no.3
• /
• pp.303-307
• /
• 2010

Acinetobacter baumannii 1625, a clinical isolate identified by Vitek and 16S rDNA sequence, showed an extended resistance to most ${\beta}$-lactams including imipenem, kanamycin, gentamicin, tobramycin, and cephalosporins of the third and fourth generations, and produced metallo-${\beta}$-lactamase (MBL) of IMP-1 type which is rare in Korea. The isolate contained a class 1 integron of about 2.5 kb in size and the integron included accA4 (aminoglycoside resistance gene), $bla_{IMP-1}$ (carbapenem resistance gene), and $bla_{OXA-2}$ (extended-spectrum ${\beta}$-lactam resistance gene) gene cassettes in order. The coexistence of IMP-1 type and OXA-2 type ${\beta}$-lactamase gene cassettes in an integron has not been reported in Korea. The transformed integron rendered the E. coli transformant resistant more than eight folds against imipenem, ampicilin, piperacillin, cefazolin, cefoperazone, and aztreonam comparing to the reference strain. This study clearly showed that the extended multi-drug resistance of A. baumannii 1625 was mainly due to the integron.

• Korean Journal of Veterinary Research
• /
• v.26 no.2
• /
• pp.229-235
• /
• 1986

1984년 5월부터 1985년 5월까지 대구(大邱), 경북(慶北), 경남(慶南) 및 충남지역(忠南地域) 7개(個) 양돈장(養豚場)의 자돈(仔豚) 및 성돈(成豚)의 분변(糞便) 및 양돈장(養豚場)의 흙, 하수(下水), 사료(飼料), 추비(推肥), 쥐 등 7,440예(例)와 대구시(大邱市) 도축장(屠畜場)의 도축돈(屠畜豚) 장간막임파절(腸間膜淋巴節) 및 직장내용물(直腸內容物) 555예(例)로부터 분리(分離)한 319주(株)의 Salmonelia속균(屬菌)을 대상으로 항균제(抗菌劑)에 대한 내성(耐性) 및 전달성(傳達性) R plasmid의 분포상황(分布狀況)을 조사(詞査)하였던 바 그 결과(結果)는 다음과 같다. 1. 공시균(供試菌) 319주(株) 중(中) 250주(株)(78.4%)가 ampicillin(An), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su), 또는 tetracycline(Tc)에 내성(耐性)을 나타내었으며, 약제별(藥劑別)로는 Su(74.9%), Sm(53.0%) 및 Tc(28.5%)에 높은 내성(耐性)이 인정(認定)되었다. 2. 내성균(耐性菌) 250주(株)의 전달성(傳達性) R plasmid 보유율(保有率)은 51.2%(128주(株))였으며, 약제별(藥劑別)로는 Am경우 100%, Tc 92. 3% 및 Cm 75.0% 순으로 보유율(保有率)이 높았다. 3. 내성균(耐性菌) 250주(株)의 내성양상(耐性樣相)은 SmSu(91주(株)), Su(59주(株)) 및 TcSmSu(50주(株))내성형(耐性型)이 대부분이었고 R plasmid 전달후(傳達後)의 내성양상(耐性樣相)은 TcSmSu(40주(株)) 및 TcSu(28주(株)) 내성형(耐性型)이 많았다. 4. 양돈장별(養豚場別) 내성균(耐性菌) 출현빈도(出現頻度)는 48.0~93.6%로 다양(多樣)하였고, 전달성(傳達性) R plasmid 보유율(保有率)은 0~77.8%로 내성균(耐性菌) 출현빈도(出現頻度)와 일치(一致)되지 않았다. 5. 공시균(供試菌) 319주(株) 중(中) 각각(各各) 2주(株)는 Rf 및 Gm에 대해 내성(耐性)을 나타내었고, 내성균(耐性菌) 250주(株) 중(中) 73.2%(183주(株))가 다제내성(多劑耐性)이었으므로 Salmonella의 다제내성화(多劑耐性化) 경향(傾向)이 있었다. 6. 내성균(耐性菌) 250주(株) 중(中) R plasmid 전달후(傳達後) 5주(株)는 TcAmCmSmSu내성형(耐性型), 1주(株)는 TcAmKmSmSu내성형(耐性型)임이 확인되었다.

• Journal of Life Science
• /
• v.28 no.10
• /
• pp.1212-1219
• /
• 2018

The critical role of heat shock protein 90 (Hsp90) in tumorigenesis led to the development of several first- and second-generation Hsp90 inhibitors, which have demonstrated promising responses in cancers. In this study, we found second-generation Hsp90 inhibitor BIIB021-resistant multidrug-resistant (MDR) human cancer cells, although BIIB021 was shown to be active in first-generation Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG)-resistant MDR cells. MCF7-MDR and HeyA8- MDR cells were more resistant to BIIB021 than their parental counterparts, indicating that BIIB021 cannot be applicable to all cancer cells expressing MDR proteins. We revealed that dimethyl-celecoxib (DMC), one of the non-steroidal anti-inflammatory drugs (NSAIDs), potentiated cytotoxicity of BIIB021 against both BIIB021-resistant and BIIB021-sensitive MDR cells. The effectiveness of NSAIDs involving celecoxib and DMC in combination with BIIB021 led to the autophagic degradation/down-regulation of mutant p53 (mutp53) that overexpressed MDR cells and the suppression of Hsp70 induction. This resulted in sensitization of MDR cells to BIIB021. Moreover, autophagy induction by sulindac sulfide, another type of NSAID, and niclosamide, an FDA-approved anthelmintic drug, potentiated 17-AAG-mediated autophagic degradation/down-regulation of mutp53 and c-Myc, client proteins of Hsp90. Therefore, our results suggest that NSAIDs and niclosamide positively enhance the anticancer activity of Hsp90 inhibitors through an autophagic pathway. They may also be new candidates for sensitizing MDR cells to Hsp90 inhibitors.

• Journal of Life Science
• /
• v.26 no.7
• /
• pp.826-834
• /
• 2016

The present investigation was undertaken to examine the effectiveness of the combination treatment of an Hsp90 inhibitor and a SIRT1 inhibitor on suppressing the growth of chemo-resistant human cancer cells. We showed that inhibition of SIRT1 effectively potentiated the cytotoxicity of 17-allylamino-17-demethoxygeldanamycin (17-AAG) and reversed Hsp90 inhibitor resistance in multidrug-resistant (MDR) human ovarian HeyA8-MDR cells. Amurensin G, a potent natural SIRT1 inhibitor, enhanced Hsp90 inhibitor-mediated abrogation of the Hsp90 chaperone function and accelerated degradation of mutated p53 (mut p53), an Hsp90 client protein, by up-regulation of ubiquitin ligase CHIP. Knock-down of CHIP significantly attenuated amurensin G-induced mut p53 degradation. Down-regulation of mut p53 reduced the expression of heat shock factor1 (HSF1)/heat shock proteins (Hsps), a major cause of Hsp90 inhibitor resistance, which led to sensitization of the MDR cells to the Hsp90 inhibitor by the SIRT1 inhibitor. Amurensin G potentiated cytotoxicity of the Hsp90 inhibitor in HeyA8-MDR cells through suppression of 17-AAG-induced Hsp70 and Hsp27 induction via down-regulation of mut p53/HSF1, and it caused activation of PARP and inhibition of Bcl-2. Our data suggests that SIRT1 inhibitors could be used to sensitize MDR cells to Hsp90 inhibitors, possibly through suppression of the mut p53/HSF1-dependent pathway, and a novel mut p53-directed action of SIRT1 inhibition could effectively prevent mut p53 accumulation in MDR cells.

• Journal of fish pathology
• /
• v.13 no.2
• /
• pp.111-119
• /
• 2000

One hundred and twenty three strains of bacterial flora collected from Kunsan bay and examined for drug resistance to 9 antibiotics. The isolated and examined bacteria were Vibrio spp.(44 strains), Pseudomonas spp.(42 strains), Aeromonas spp.(26 strains), Moraxella spp.(9 strains), Enterobacteria spp.(6 strains), Bordetella spp.(3 strains), Alkaligenesis spp.(3 strains), Staphylococcus spp.(3 strains), and Flavobacterium spp.(2 strains). The drugs used were Ampicillin(AM), Penicillin-G(PM), Rifampicin(RF), Streptomycin(SM), Oxolinic acid (OA), Nalidixic acid(NA), Oxytetracycline(OT), Amikacin(AK), and Enorfloxacin(EF). Forty two strains were found to be sensitive to all drugs. The remaining strains showed resistance to various combinations of drugs. Among the resistant strains were mostly restricted to AM(54 strains/43.9%), PM(47 strains/38.2%), RF(35 strains/28.4%), SM(9 strains), OA(5 strains/ 4.06%), and NA(1 strains/0.8%), in combination at high degree showing 15 different drug resistant patterns. The most frequently showed resistant patterns were AM-PM-RF(16 strains/13.4%), AM-PM(8 strains/6.5%), and PM-RF(7 strains/5.6%). These results suggested that Kunsan bay were contaminated with various strains of highly resistant strains to drugs(AM, PM and RF). These results suggest that high levels of various antibiotics have already been introduced to Kunsan bay. Furthermore it seems that chemotherapy of fish disease has become extremely difficult because of the acquirement of multi-drug resistance to wide range of antibiotics.

• Korean Journal of Clinical Laboratory Science
• /
• v.54 no.2
• /
• pp.125-132
• /
• 2022

The prevalence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) are increasing. We analyzed the patterns of drug resistance and tracking period days of acquiring anti-mycobacterial resistance. From January 2010 to December 2019, drug susceptibility tests (DST) were performed by the absolute concentration method using the Löwenstein-Jensen solid medium and pyrazinamidase activity test (to assess pyrazinamide resistance) in samples from patients who were referred to the Green Cross Laboratories in Yongin. Among the cases that showed resistance to one or more anti-tuberculosis drugs, 55 patients (33.1%) were resistant to isoniazid (INH) at the time of initial referral, and the rates for the development of resistant anti-tuberculosis drugs were ethambutol (EMB) (26.6%), rifampicin (RFP) (21.9%), quinolones (QUI) (21.9%) and pyrazinamide (PZA) (10.9%), in that order. In the cases sensitive to all 10 anti-tuberculosis drugs initially, the development of resistance to INH was the most frequent, seen in 43 patients (7.2%). The average follow-up period was 435.6 days, and the resistance development was observed in the order of INH (7.2%), RFP (3.9%), SM (1.9%), QUI (0.7%), amikacin (AMK) (0.5%), and EMB (0.5%). The conversion of susceptible strains to resistant strains is an important warning sign for the patient, especially in cases of conversion to MDR or XDR. This information would be helpful for improving patient care during TB treatment.