• Journal of Periodontal and Implant Science
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• 제45권6호
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• pp.223-228
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• 2015

Purpose: The goal of this study was to characterize the patterns of antimicrobial resistance and virulence genes in samples of Staphylococcus aureus (S. aureus) isolated from periodontitis patients. Methods: From July 2015 to August 2015, oral saliva was collected from a total of 112 patients diagnosed with periodontitis, including 80 outpatients in dental hospitals and 32 patients in dental clinics located in Seoul and Cheonan. The samples were subjected to a susceptibility test to evaluate the prevalence of antimicrobial resistance, and the pathogenic factors and antimicrobial resistance factors in the DNA of S. aureus were analyzed using polymerase chain reaction. Results: A susceptibility test against 15 antimicrobial agents showed that 88% of cultures were resistant to ampicillin, 88% to penicillin, and 2% to oxacillin. Resistance to at least two drugs was observed in 90% of cultures, and the most common pattern of multidrug resistance was to ampicillin and penicillin. Enterotoxins were detected in 65.9% of samples. The cell hemolysin gene hld was detected in 100% of cultures and hla was detected in 97.6% of samples. All strains resistant to penicillin and ampicillin had the blaZ gene. The aph(3')IIIa gene, which encodes an aminoglycoside modifying enzyme, was detected in 46.3% of samples. Conclusions: In the treatment of oral S. aureus infections, it is important to identify the pathogenic genes and the extent of antimicrobial resistance. Furthermore, it is necessary to study patterns of antimicrobial resistance and cross-infection in the context of periodontological specialties in which antimicrobials are frequently used, such as maxillofacial surgery, where the frequency of antimicrobial use for minor procedures such as implant placement is increasing.

• 한국수산과학회지
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• 제47권3호
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• pp.247-254
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• 2014

To investigate the acquisition of quinolone resistance, we examined mutations in the quinolone resistance-determining region (QRDR) of type II topoisomerase genes in ciprofloxacin (CIP)-resistant clinical isolates and in vitro mutants of Streptococcus parauberis. The CIP-resistant clinical isolates had one base change responsible for a Ser-79${\rightarrow}$Thr in the QRDR of parC. However, the CIP-resistant in vitro mutants had an altered QRDR of parC (Ser-79${\rightarrow}$Ile) that differed from that of the isolates. None of the CIP-resistant S. parauberis clinical isolates or in vitro mutants exhibited amino acid changes in gyrA or gyrB. However, even though involvement in the increased resistance was not clear, an Arg-449${\rightarrow}$Ser mutation outside of the QRDR of parE was detected in CIP-resistant mutant 2P1. These results suggest that the topoisomerase IV gene, parC (and possibly parE, as well), is the primary ciprofloxacin target in S. parauberis. Additionally we established a high-resolution melting (HRM) assay capable of detecting the dominant mutation in four type II topoisomerase genes conferring ciprofloxacin resistance. These rapid and reliable assays may provide a convenient method of surveillance for genetic mutations conferring antibiotic resistance.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2793-2800
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• 2015

In molecular-targeted cancer therapy, acquired resistance to gemcitabine is a major clinical problem that reduces its effectiveness, resulting in recurrence and metastasis of cancers. In spite of great efforts to reveal the overall mechanism of acquired gemcitabine resistance, no definitive genetic factors have been identified that are absolutely responsible for the resistance process. Therefore, we performed a cross-platform meta-analysis of three publically available microarray datasets for cancer cell lines with acquired gemcitabine resistance, using the R-based RankProd algorithm, and were able to identify a total of 158 differentially expressed genes (DEGs; 76 up- and 82 down-regulated) that are potentially involved in acquired resistance to gemcitabine. Indeed, the top 20 up- and down-regulated DEGs are largely associated with a common process of carcinogenesis in many cells. For the top 50 up- and down-regulated DEGs, we conducted integrated analyses of a gene regulatory network, a gene co-expression network, and a protein-protein interaction network. The identified DEGs were functionally enriched via Gene Ontology hierarchy and Kyoto Encyclopedia of Genes and Genomes pathway analyses. By systemic combinational analysis of the three molecular networks, we could condense the total number of DEGs to final seven genes. Notably, GJA1, LEF1, and CCND2 were contained within the lists of the top 20 up- or down-regulated DEGs. Our study represents a comprehensive overview of the gene expression patterns associated with acquired gemcitabine resistance and theoretical support for further clinical therapeutic studies.

• Parasites, Hosts and Diseases
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• 제50권4호
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• pp.379-384
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• 2012

Resistance of Plasmodium spp. to anti-malarial drugs is the primary obstacle in the fight against malaria, and molecular markers for the drug resistance have been applied as an adjunct in the surveillance of the resistance. In this study, we investigated the prevalence of mutations in pvmdr1, pvcrt-o, pvdhfr, and pvdhps genes in temperate-zone P. vivax parasites from central China. A total of 26 isolates were selected, including 8 which were previously shown to have a lower susceptibility to chloroquine in vitro. For pvmdr1, pvcrt-o, and pvdhps genes, no resistance-conferring mutations were discovered. However, a highly prevalent (69.2%), single-point mutation (S117N) was found in pvdhfr gene. In addition, tandem repeat polymorphisms existed in pvdhfr and pvdhps genes, which warranted further studies in relation to the parasite resistance to antifolate drugs. The study further suggests that P. vivax populations in central China may still be relatively susceptible to chloroquine and sulfadoxine-pyrimethamine.

• Fisheries and Aquatic Sciences
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• 제21권2호
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• pp.3.1-3.10
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• 2018

Background: Vibrio parahaemolyticus is one of the most common causes of seafood-borne illnesses in Korea, either directly or indirectly, by consuming infected seafood. Many studies have demonstrated the antibiotic susceptibility profile of V. parahaemolyticus. This strain has developed multiple antibiotic resistance, which has raised serious public health and economic concerns. This article reviews the food-borne outbreaks, distributions, virulence, and antibiotic resistance profiles of V. parahaemolyticus in Korea during 2003-2016. Main body: V. parahaemolyticus infections appeared to be seasonally dependent, because 69.7% of patient infections occurred in both August and September during 2003-2016. In addition, the occurrence of V. parahaemolyticus in marine environments varies seasonally but is particularly high in July, August, and September. V. parahaemolyticus isolated from aquaculture sources on the Korean coast varied in association with virulence genes, some did not possess either the tdh (thermostable direct hemolysin) or trh (tdh-related hemolysin) genes, and a few were positive for only the trh gene or both genes. The high percentage of ampicillin resistance against V. parahaemolyticus in the aquatic environment suggests that ampicillin cannot be used to effectively treat infections caused by this organism. Short conclusion: This study shows that the observed high percentage of multiple antibiotic resistance to V. parahaemolyticus is due to conventionally used antibiotics. Therefore, monitoring the antimicrobial resistance patterns at a national level and other solutions are needed to control aquaculture infections, ensure seafood safety, and avoid threats to public health caused by massive misuse of antibiotics.

• 한국습지학회지
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• 제16권2호
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• pp.269-274
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• 2014

본 연구의 목적은 항생제 내성 균과 유전자 및, 항생제 내성 전달을 제어하는데 필요한 살균능 (CT, 농도 * 접촉 시간)을 서로 비교하는데 있다. 이를 위하여, 이를 위해 각기 다른 염소 주입농도(C)와 접촉시간(T)에 따라 각각의 항생제 내성 제거를 산정하였다. 그 결과 항생제 내성균 90%(1 log)이상 제어를 위해서는 CT 값(176~353 mg min/L)이 필요하였으며, 항생제 내성 유전자의 제거를 위한 CT 값은 195~372 mg min/L 이었다. 또한 항생제 내성 유전자의 전이 90% 이상 제거를 위한 CT 값은 187~489 mg min/L이었다. 따라서, 본 연구조건에서는 항생제 내성 유전자 및 유전자의 전이에 대한 제어를 위해서는 항생제 내성균 제어보다 더 높은 소독능이 필요함을 알 수 있었다.

• Genomics & Informatics
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• 제21권2호
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• pp.20.1-20.10
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• 2023

Aromatase inhibitors (AI) are drugs that are widely used in treating estrogen receptor (ER)-positive breast cancer patients. Drug resistance is a major obstacle to aromatase inhibition therapy. There are diverse reasons behind acquired AI resistance. This study aims at identifying the plausible cause of acquired AI resistance in patients administered with non-steroidal AIs (anastrozole and letrozole). We used genomic, transcriptomic, epigenetic, and mutation data of breast invasive carcinoma from The Cancer Genomic Atlas database. The data was then separated into sensitive and resistant sets based on patients' responsiveness to the non-steroidal AIs. A sensitive set of 150 patients and a resistant set of 172 patients were included for the study. These data were collectively analyzed to probe into the factors that might be responsible for AI resistance. We identified 17 differentially regulated genes (DEGs) among the two groups. Then, methylation, mutation, miRNA, copy number variation, and pathway analyses were performed for these DEGs. The top mutated genes (FGFR3, CDKN2A, RNF208, MAPK4, MAPK15, HSD3B1, CRYBB2, CDC20B, TP53TG5, and MAPK8IP3) were predicted. We also identified a key miRNA - hsa-mir-1264 regulating the expression of CDC20B. Pathway analysis revealed HSD3B1 to be involved in estrogen biosynthesis. This study reveals the involvement of key genes that might be associated with the development of AI resistance in ER-positive breast cancers and hence may act as a potential prognostic and diagnostic biomarker for these patients.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권4호
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• pp.252-263
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• 2001

Nematode infections compromise human health and reduce agricultural productivtiy. Experiments that exploit the powerful molecular genetics of the free-living nematode Caenorhabdl - elegans have contributed to our understanding of how the major classes of anthelmintic nema-tocides kill worms and how worms might evolve resistance to these drugs In C. elegans, as in parasites, benzimidixoles interfere with microtubule polyumerization the imidazothiazoles/tetra-hydropyrimidines activate nicotinic acetylcholine receptors, and the macrocyclic la ctones activate qlutamate-gate chloride chanels. Mutant alleles of genes that encode drug targes often confer resistance in C. elegans. Preliminary evidence suggests that alleles of homologous genes in parasites will, in many cases, also play a role in resistance. Thus information acquired from C. elegans can be usefully applied to understand the mechanisms of drug sensitivity and the genetics of resis-tance in parasites.

• 한국미생물·생명공학회지
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• 제52권1호
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• pp.88-90
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• 2024

We report the whole genome sequence of a linezolid-resistant and vancomycin-susceptible Enterococcus faecalis strain, ES-2-1, which was isolated from a pig stool in South Korea. The assembled genome of ES-2-1 consists of a 2,648,168-bp circular chromosome containing the optrA gene (encoding the ABC-F type ribosomal protection protein), an 84,891-bp plasmid containing numerous antimicrobial resistance genes, and an 82,106-bp cryptic plasmid. The ES-2-1 strain belongs to sequence type 1024 (ST1024) and carries multidrug resistant genes including the optrA (oxazolidinone phenicol transferable resistance A) gene, which confers linezolid resistance.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.72.2-73
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• 2003

We found a soybean (Glycine max) cultivar 561 that was strongly resistant to a virulent bacterial strain of a Pseudomonas spp. Further identification revealed that the Pseudomonas spp. was a strain of Pseudomonas aeruginosa. Furthermore we identified specific genes involved in the resistance of soybean 561 and analyzed the pattern of gene expression against the Pseudomonas infection using differential-display reverse transcription PCR (DDRT-PCR). More than 126 cDNA fragments representing mRNAs were induced within 48 hours of bacteria inoculation. Among them, 28 cDNA fragments were cloned and sequenced. Twelve differentially displayed clones with open reading frames had unknown functions. Sixteen selected cDNA clones were homologous to known genes in the other organisms. Some of the identified cDNAs were pathogenesis-related genes (PR genes) and PR-like genes. These cDNAs included a putative calmodulin-binding protein, an endo-1,3-1,4-b-D-glucanase, a b-1,3-endoglucanase, a b-1,3-exoglucanase, a phytochelatin synthetase-like gene, a thiol pretense, a cycloartenol synthase, and a putative receptor-like sorineithreonine protein kinase. Among them, we found that four genes were putative pathogenesis-related genes (PR) induced significantly by the p. aeruginosa infection. These included a calmodulin-binding protein gene, a b-1,3-endoglucanase gene, a receptor-like sorine/threonine protein kinase gene, and pS321 (unknown function). These results suggest that the differentially expressed genes may mediate the strong resistance of soybean 561 to Pseudomonas aeruoginosa.