• Korean Journal of Microbiology
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• v.49 no.2
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• pp.126-130
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• 2013

The major aim of this study was to investigate the distribution of genes that encode multidrug efflux pumps in Enterococci spp. isolates from bovine milk samples and antibiotic resistance patterns of these strains. Of the 245 isolates, 44.1% showed ampicillin resistance, 79.2% showed erythromycin resistance, 76.3% showed tetracycline resistance and 36.3% showed chloramphenicol resistance. In case of vancomycin and ciprofloxacin, all of the isolates were susceptible to these antibiotics. Of the 245 enterococcal isolates, 82.1% have MFS type eme(A) gene, 72.7% have ABC type efr(A) gene, 77.1% have ABC type efr(B) gene, and 71.8% have ABC type lsa gene. In case of Enterococcus faecalis, the original strain for these genes, 92.5% have eme(A), 87.4% have efr(A), 88.4% have efr(B), and 88.4% have lsa. Interestingly, in case of different species of Enterococci, eme(A) was also detected in four strains of E. faecium, seven strains of E. avium, four strains of E. durans and two strains of E. raffinosus. efr(A) was also detected in two strains of E. faecium and two strains of E. durans and efr(B) was also detected in four strains of E. faecium, five strains of E. avium and four strains of E. durans. This means the possibility of co-transfer of resistance genes between Enterococci species in natural environment. These results are the first report describing the presence of same multidrug efflux pumps in different species of Enterococci in Korea.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1214-1220
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• 2005

Decreased porin-mediated outer membrane penetration of hydrophilic antibiotics is a common mechanism of antibiotic resistance in Gram-negative bacteria. This study was undertaken to determine whether a null mutation in Pseudomonas putida would suppress porin synthesis, and therefore reduce the susceptibility of the organism to streptomycin, norfloxacin, and tetracycline. Inverse PCR amplification and double-stranded DNA sequencing were used to identify chromosomal genes carrying TnphoA'-1 inserts. Genome database available was used to identify putative homologue genes, one of which encodes protein with homology to domains of the MutS of P. putida, suggesting a crucial role in the multidrug resistance. Increased resistance to streptomycin, norfloxacin, and tetracycline might be due to accumulation of compensatory mutations. Either no growth or slow growth was observed in P. putida KH1027 when grown in minimal medium containing gluconate, glucose, or citrate; however, it is not clear whether the growth patterns contributed to the multidrug resistance.

• Journal of Integrative Natural Science
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• v.4 no.1
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• pp.23-30
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• 2011

Multidrug resistance (MDR) is one of the main obstacles in the chemotherapy of cancer. MDR is associated with the over expression of P-glycoprotein (P-gp), resulting in increased efflux of chemotherapy from cancer cells. Inhibiting P-gp as a method to reverse MDR in cancer patients has been studied extensively, but the results have generally been disappointing. First-generation agents were limited by unacceptable toxicity, whereas second-generation agents had better tolerability but were confounded by unpredictable pharmacokinetic interactions and interactions with other transporter proteins. Third-generation inhibitors have high potency and specificity for P-gp. Furthermore, pharmacokinetic studies to date have shown no appreciable impact on drug metabolism and no clinically significant drug interactions with common chemotherapy agents. Third-generation P-gp inhibitors have shown promise in clinical trials. The continued development of these agents may establish the true therapeutic potential of P-gp-mediated MDR reversal.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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• pp.219-220
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• 1996

The pKH2 isolated from the multidrug-resistant Staphylococcus aureus SA2 is a 40.98-kb plasmid and mediates resistance to ampicillin, clindamycin, erythromycin, kanamycin, and streptomycin. The 3.4-kb HindIII fragment conferring kanamycin resistance was cloned from the pKH2 into pBluescriptII $KS^+$ and partial sequence determination of that fragment was carried out. Sequence analysis revealed that the kanamycin resistance gene which encoded aminoglycoside 3'-phosphotransferase was linked to the streptothricin resistance gene. But a nonsense mutation was found in the streptothricin resistance gene and this mutation resulted in a truncated protein of streptothricin acetyltransferase. Homology comparison with nucleotide sequence databases revealed that the 3.4-kb HindIII fragment of pKH2 had been derived not from S. aureus but from Gram-negative Campylobacter coli.

• Biomedical Science Letters
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• v.11 no.2
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• pp.115-119
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• 2005

A total of 28 Salmonella enterica serovar Typhimurium isolated from diseased pigs and swine carcasses between 2001 and 2003 were characterized by the antimicrobial resistance profiles, PCR for detection of S. Typhimurium DT104 and pulsed-field gel electrophoresis (PFGE) with the restriction enzyme XbaI. All but one isolate presented multidrug resistance (MDR) to more than two antibiotics tested. A total of 11 resistance profiles were observed, and two phenotypes, ST and ASSuTG, were the most common among them. Two isolates were found to be S. Typhimurium DT104 isolates by PCR, and their resistance profile did not show the DT104 typical resistance type ACSSuT, but ACSSuTGK instead. PFGE identified 11 banding patterns in dendrogram, and three main clusters (designated A to C) were represented. Interestingly, sixteen of 19S. Typhimurium isolates belonging to cluster B showed an identical band pattern.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.242-246
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• 1996

Hatomarubigins inhibited the growth of various cancer cell lines including multidrug-resistance cells. Hatomarubigins were found to potentiate the colchicine- and vinblastine-induced cytotoxicity against KB-C2 cell, but not the adriamycin-induced cytotoxicity against KB-C2 cells. Hatomarubigins didn't affect the sensitive KB cells. These results suggest that hatomarubigins are specific potentiators of colchicine. Among four hatomarubigins, hatomarubigin A sho- wed the highest synergestic effect on colchine-induced cytotoxicity. Similar effect of hatomarubigin A was found against V79/ADM cells.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.779-780
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• 2009

• Natural Product Sciences
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• v.23 no.4
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• pp.286-290
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• 2017

Multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are highly dangerous nosocomial pathogens, cause the symptoms of skin infections, pressure sores, sepsis, blood stream and wound infections. Unfortunately, these pathogens are immune to the most common antibiotics, such as, carbapenem, aminoglycoside and fluoroquinolone. Therefore, it is imperative that new and effective antibiotics be developed. In the present study, the antimicrobial effects of Aloe vera MAP (modified Aloe polysaccharide) on Staphylococcus aureus and Bacillus subtilis, Escherichia coli and Enterobacter aerogenes, and clinical Pseudomonas aeruginosa and clinical Acinetobacter baumannii were comprehensibly investigated. Prior to the growth inhibition effect measurement and antibiotic disc diffusion assay on gram-positive and gram-negative bacteria and selected multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, antimicrobial resistance screening was performed for the multidrug-resistant bacteria obtained from clinical isolates. The results for showed the Aloe vera MAP had a concentration-dependent effect on all of examined bacteria, particularly on Pseudomonas aeruginosa. Anti-inflammatory and anti-oxidant experiments were also performed dose dependently effects to confirm the beneficial physiological effects of Aloe vera MAP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5012-5018
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• 2011

According to the nationwide survey of tuberculosis from 1965 to 1995, the incidence and drug resistance rate of tuberculosis have been decreased in Korea, but the prevalence of multidrug resistance of Mycobacterium tuberculosis is still a serious problem. The purpose of this study is to investigate the drug resistance rate and pattern of tuberculosis in Daejeon from 2001 to 2008. Of the total 581cases where the drug susceptibility test was performed, resistance to at least one anti-TB drug was found in 104 cases(17.9%) of these, 68(11.7%) were resistant to at least INH and 41(7.1%) were resistant to at least RFP. Single-drug resistance was found for isolates from 37(6.4%) ; 18(3.1%) of these were resistant to INH and 5(0.9%) to RFP. Multidrug resistance, where TB was resistant to at least isoniazid and refampin, was found in 35 cases(6.0%). and Factors associated with MDR-TB included age under 40-60.The drug-resistance rate of pulmonary TB, especially MDR-TB, is higher in the initial treated patients at a private referral hospital than in those in the pubulic sector. Initial drug resistance is common and the drug susceptibility test is informative for pulmonary TB patients who have not received previous TB treatment. The need for an improved control program, coupled with early diagnosis of MDR-TB, to reduce the spread and development of resistance. Multidrug resistance rate is still problem in korea. Efforts to decrease multidrug resistance rate either independently or in cooperation with the pubulic sector will be needed.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.135-144
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• 2018

The rapid increase in number and diversity of Extended Spectrum ${\beta}$-Lactamases (ESBLs) producing Enterobacteriaceae in natural aquatic environment is a major health concern worldwide. This study investigates abundance and distribution of ESBL producing multidrug resistant Enterobacteriaceae and molecular characterization of ESBL genes among isolates from highly polluted stretch of river Yamuna, India. Water samples were collected from ten different sites distributed across Delhi stretch of river Yamuna, during 2014-15. A total of 506 non duplicate Enterobacteriaceae isolates were obtained. Phenotypic detection of ESBL production and antibiotic sensitivity for 15 different antibiotics were performed according to CLSI guidelines (Clinical and Laboratory Standard Institute, 2015). A subset of ESBL positive Enterobacteriaceae isolates were identified by 16S rRNA gene and screened for ESBL genes, such as $bla_{CTX-M}$, $bla_{TEM}$ and $bla_{OXA}$. Out of 506 non-duplicate bacterial isolates obtained, 175 (34.58%) were positive for ESBL production. Susceptibility pattern for fifteen antibiotics used in this study revealed higher resistance to cefazolin, rifampicin and ampicillin. A high proportion (76.57%) of ESBL positive isolates showed multidrug resistance phenotype, with MAR index of 0.39 at Buddha Vihar and Old Delhi Railway bridge sampling site. Identification and PCR based characterization of ESBL genes revealed the prevalence of $bla_{CTX-M}$ and $bla_{TEM}$ genes to be 88.33% and 61.66%, respectively. Co-occurrence of $bla_{CTX-M}$ and $bla_{TEM}$ genes was detected in 58.33% of the resistant bacteria. The $bla_{OXA}$ gene was not detected in any isolates. This study highlights deteriorating condition of urban aquatic environment due to rising level of ESBL producing Enterobacteriaceae with multidrug resistance phenotype.