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Sample records for tetracycline resistance gene

  1. Transfer of tetracycline resistance gene (tet ) between replicons in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... (71.4%), gentamicin (43.5%), nalidixic acid (38.3%) and nitrofurantoin (7.7%; Table 2). The results of antibiotic susceptibility test also indicated that E. coli showed higher rates of resistance to most of the antibiotics. A total of 110 (71.4%) isolates were resistant to tetracy- cline. Tetracycline resistant gene tetr ...

  2. Transfer of tetracycline resistance gene (tetr) between replicons in ...

    African Journals Online (AJOL)

    Transfer of tetracycline resistance gene (tetr) between replicons in some enteric bacteria of diarrhoeal origin from some hospitals in South-South, Nigeria. ... Attempt was made to transfer the tetr gene from one replicon to the other within the same species and from one genus to the other. The rate of intra-species transfer of ...

  3. Tetracycline residues and tetracycline resistance genes in groundwater impacted by swine production facilities

    Science.gov (United States)

    Mackie, R.I.; Koike, S.; Krapac, I.; Chee-Sanford, J.; Maxwell, Susan; Aminov, R.I.

    2006-01-01

    Antibiotics are used at therapeutic levels to treat disease; at slightly lower levels as prophylactics; and at low, subtherapeutic levels for growth promotion and improvement of feed efficiency. Over 88% of swine producers in the United States gave antimicrobials to grower/finisher pigs in feed as a growth promoter in 2000. It is estimated that ca. 75% of antibiotics are not absorbed by animals and are excreted in urine and feces. The extensive use of antibiotics in swine production has resulted in antibiotic resistance in many intestinal bacteria, which are also excreted in swine feces, resulting in dissemination of resistance genes into the environment.To assess the impact of manure management on groundwater quality, groundwater samples have been collected near two swine confinement facilities that use lagoons for manure storage and treatment. Several key contaminant indicators-including inorganic ions, antibiotics, and antibiotic resistance genes-were analyzed in groundwater collected from the monitoring wells. Chloride, ammonium, potassium, and sodium were predominant inorganic constituents in the manure samples and served as indicators of groundwater contamination. Based on these analyses, shallow groundwater has been impacted by lagoon seepage at both sites. Liquid chromatography-mass spectroscopy (LC-MS) was used to measure the dissolved concentrations of tetracycline, chlortetracycline, and oxytetracycline in groundwater and manure. Although tetracyclines were regularly used at both facilities, they were infrequently detected in manure samples and then at relatively trace concentrations. Concentrations of all tetracyclines and their breakdown products in the groundwater sampled were generally less than 0.5 ??g/L.Bacterial tetracycline resistance genes served as distinct genotypic markers to indicate the dissemination and mobility of antibiotic resistance genes that originated from the lagoons. Applying PCR to genomic DNA extracted from the lagoon and

  4. Effect of tetracycline residues in pig manure slurry on tetracycline-resistant bacteria and resistance gene tet(M) in soil microcosms

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Wulff, Gitte; Vaclavik, Elvira

    2006-01-01

    longer than tetracycline-resistant enterococci could be isolated (limit of detection 100 CFU/g soil) probably due to viable but not culturable (VBNC) bacteria with tet(M), horizontal gene transfer of tet(M) to indigenous soil bacteria or presence of "free" DNA. The concentration of chlortetracycline......Effects of tetracycline residues from pig manure slurry on the prevalence of tetracycline-resistant bacteria and the tetracycline resistance gene, tet(M), were studied in soil microcosms. Four types of soil microcosms were established for a period of 152 days, supplemented with combinations of pig...... manure slurry and a tetracycline-resistant Enterococcus faecalis, CG I 10, containing the tetracycline resistance gene tet(m) (on the conjugative transposon, Tn916). The prevalence of both tetracycline-resistant aerobic bacteria and tetracycline-resistant enterococci declined rapidly until day 45 where...

  5. A Comprehensive Insight into Tetracycline Resistant Bacteria and Antibiotic Resistance Genes in Activated Sludge Using Next-Generation Sequencing

    OpenAIRE

    Huang, Kailong; Tang, Junying; Zhang, Xu-Xiang; Xu, Ke; Ren, Hongqiang

    2014-01-01

    In order to comprehensively investigate tetracycline resistance in activated sludge of sewage treatment plants, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential tetracycline resistant bacteria (TRB) and antibiotic resistance genes (ARGs) in sludge cultured with different concentrations of tetracycline. Pyrosequencing of 16S rRNA gene revealed that tetracycline treatment greatly affected the bacterial community structure of the sludge. Nine genera cons...

  6. Rapid Detection of Bacterial Antibiotic Resistance: Preliminary Evaluation of PCR Assays Targeting Tetracycline Resistance Genes

    Science.gov (United States)

    2007-08-01

    Doxycycline Brucella spp. Brucellosis Aminoglycosides, Doxycycline, Tetracyclines Burkholderia mallei Glanders Penicillins, Tetracyclines...antibiotics: Mode of action, applications, molecular biology, and epidemiology of bacterial resistance. Molecular Biology Reviews 65: 232-260 5

  7. The impact of a freshwater fish farm on the community of tetracycline-resistant bacteria and the structure of tetracycline resistance genes in river water.

    Science.gov (United States)

    Harnisz, Monika; Korzeniewska, Ewa; Gołaś, Iwona

    2015-06-01

    The aim of this study was to assess the impact of a fish farm on the structure of antibiotic resistant bacteria and antibiotic resistance genes in water of Drwęca River. Samples of upstream river waters; post-production waters and treated post-production waters from fish farm; as well as downstream river waters were monitored for tetracycline resistant bacteria, tetracycline resistant genes, basic physico-chemical parameters and tetracyclines concentration. The river waters was characterized by low levels of pollution, which was determined based on water temperature, pH and concentrations of dissolved oxygen and tetracycline antibiotics. Culture-dependent (heterotrophic plate counts, counts of bacteria resistant to oxytetracycline (OTC(R)) and doxycycline (DOX(R)), minimum inhibitory concentrations for oxytetracycline and doxycycline, multidrug resistance of OTC(R) and DOX(R), qualitative composition of OTC(R) and DOX(R), prevalence of tet genes in resistant isolates) and culture-independent surveys (quantity of tet gene copies) revealed no significant differences in the abundance of antibiotic-resistant bacteria and antibiotic resistance genes between the studied samples. The only way in which the fish farm influenced water quality in the Drwęca River was by increasing the diversity of tetracycline-resistance genes. However, it should also be noted that the bacteria of the genera Aeromonas sp. and Acinetobacter sp. were able to transfer 6 out of 13 tested tet genes into Escherichiacoli, which can promote the spread of antibiotic resistance in the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Diverse tetracycline resistant bacteria and resistance genes from coastal waters of Jiaozhou Bay.

    Science.gov (United States)

    Dang, Hongyue; Ren, Jing; Song, Linsheng; Sun, Song; An, Liguo

    2008-02-01

    Environmental microbiology investigation was carried out in Jiaozhou Bay to determine the source and distribution of tetracycline-resistant bacteria and their resistance mechanisms. At least 25 species or the equivalent molecular phylogenetic taxa in 16 genera of resistant bacteria could be identified based on 16S ribosomal deoxyribonucleic acid sequence analysis. Enterobacteriaceae, Pseudomonadaceae, and Vibrionaceae constituted the majority of the typical resistant isolates. Indigenous estuarine and marine Halomonadaceae, Pseudoalteromonadaceae, Rhodobacteraceae, and Shewanellaceae bacteria also harbored tetracycline resistance. All the six resistance determinants screened, tet(A)-(E) and tet(G), could be detected, and the predominant genes were tet(A), tet(B), and tet(G). Both anthropogenic activity-related and indigenous estuarine or coastal bacteria might contribute to the tet gene reservoir, and resistant bacteria and their molecular determinants may serve as bioindicators of coastal environmental quality. Our work probably is the first identification of tet(E) in Proteus, tet(G) in Acinetobacter, tet(C) and tet(D) in Halomonas, tet(D) and tet(G) in Shewanella, and tet(B), tet(C), tet(E), and tet(G) in Roseobacter.

  9. Spread of tetracycline resistance genes at a conventional dairy farm

    NARCIS (Netherlands)

    Kyselková, Martina; Jirout, Jiří; Vrchotová, Naděžda; Schmitt, Heike; Elhottová, Dana

    2015-01-01

    The use of antibiotics in animal husbandry contributes to the worldwide problem of increasing antibiotic resistance in animal and human pathogens. Intensive animal production is considered an important source of antibiotic resistance genes released to the environment, while the contribution of

  10. Transfer of tetracycline resistance genes with aggregation substance in food-borne Enterococcus faecalis.

    Science.gov (United States)

    Choi, Jong-Mi; Woo, Gun-Jo

    2015-04-01

    Enterococcus faecalis has the ability to conjugate with the aid of aggregation substance (AS) and inducible sex pheromones to exchange genetic elements in food matrix. To evaluate the food safety condition and the transferable factor, 250 tetracycline-resistant food-borne E. faecalis were collected in Korea. Among the isolates, a majority of tetracycline-resistant isolates (49.6 %) harbored both the tet(M) and tet(L) genes together, followed by tet(M) (19.6 %), and tet(L) (6.8 %) alone. Also, we found the combination of tet(L)/tet(M)/tet(O) or tet(M)/tet(O). We identified two tet(S) genes including the isolate carrying tet(M) + tet(S) genes. Additionally, most E. faecalis were positive for cpd and ccf (both 96.8 %) followed by cob (57.2 %). Through mating experiments, we confirmed E. faecalis possessing the Int-Tn gene and/or any AS gene successfully transferred tet genes to JH2-2 E. faecalis, whereas neither E. faecalis carrying AS genes nor the Int-Tn gene showed the conjugation. Pulsed-field gel electrophoresis results supported a distinct pattern, implying transfer of genetic information. Our study revealed a high occurrence of tetracycline resistance genes in E. faecalis from various foods. The widespread dissemination of tetracycline resistance genes would be promoted to transfer tetracycline resistance genes by pheromone-mediated conjugation systems.

  11. A comprehensive insight into tetracycline resistant bacteria and antibiotic resistance genes in activated sludge using next-generation sequencing.

    Science.gov (United States)

    Huang, Kailong; Tang, Junying; Zhang, Xu-Xiang; Xu, Ke; Ren, Hongqiang

    2014-06-05

    In order to comprehensively investigate tetracycline resistance in activated sludge of sewage treatment plants, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential tetracycline resistant bacteria (TRB) and antibiotic resistance genes (ARGs) in sludge cultured with different concentrations of tetracycline. Pyrosequencing of 16S rRNA gene revealed that tetracycline treatment greatly affected the bacterial community structure of the sludge. Nine genera consisting of Sulfuritalea, Armatimonas, Prosthecobacter, Hyphomicrobium, Azonexus, Longilinea, Paracoccus, Novosphingobium and Rhodobacter were identified as potential TRB in the sludge. Results of qPCR, molecular cloning and metagenomic analysis consistently indicated that tetracycline treatment could increase both the abundance and diversity of the tet genes, but decreased the occurrence and diversity of non-tetracycline ARG, especially sulfonamide resistance gene sul2. Cluster analysis showed that tetracycline treatment at subinhibitory concentrations (5 mg/L) was found to pose greater effects on the bacterial community composition, which may be responsible for the variations of the ARGs abundance. This study indicated that joint use of 454 pyrosequencing and Illumina high-throughput sequencing can be effectively used to explore ARB and ARGs in the environment, and future studies should include an in-depth investigation of the relationship between microbial community, ARGs and antibiotics in sewage treatment plant (STP) sludge.

  12. A Comprehensive Insight into Tetracycline Resistant Bacteria and Antibiotic Resistance Genes in Activated Sludge Using Next-Generation Sequencing

    Directory of Open Access Journals (Sweden)

    Kailong Huang

    2014-06-01

    Full Text Available In order to comprehensively investigate tetracycline resistance in activated sludge of sewage treatment plants, 454 pyrosequencing and Illumina high-throughput sequencing were used to detect potential tetracycline resistant bacteria (TRB and antibiotic resistance genes (ARGs in sludge cultured with different concentrations of tetracycline. Pyrosequencing of 16S rRNA gene revealed that tetracycline treatment greatly affected the bacterial community structure of the sludge. Nine genera consisting of Sulfuritalea, Armatimonas, Prosthecobacter, Hyphomicrobium, Azonexus, Longilinea, Paracoccus, Novosphingobium and Rhodobacter were identified as potential TRB in the sludge. Results of qPCR, molecular cloning and metagenomic analysis consistently indicated that tetracycline treatment could increase both the abundance and diversity of the tet genes, but decreased the occurrence and diversity of non-tetracycline ARG, especially sulfonamide resistance gene sul2. Cluster analysis showed that tetracycline treatment at subinhibitory concentrations (5 mg/L was found to pose greater effects on the bacterial community composition, which may be responsible for the variations of the ARGs abundance. This study indicated that joint use of 454 pyrosequencing and Illumina high-throughput sequencing can be effectively used to explore ARB and ARGs in the environment, and future studies should include an in-depth investigation of the relationship between microbial community, ARGs and antibiotics in sewage treatment plant (STP sludge.

  13. Construction of an extended range whole-cell tetracycline biosensor by use of the tet(M) resistance gene

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Hansen, Lars Hestbjerg; Sørensen, Søren Johannes

    2005-01-01

    protein gene. Tetracycline, oxytetracycline, chlortetracycline and minocycline all effectively induced the resulting Escherichia coli MC4100/pTGM biosensor and similar dose-response characteristics were recorded by flow cytometry for all four compounds. The novel tetracycline biosensor was responsive......An extended range whole-cell tetracycline biosensor strain was constructed by insertion of the tet(M) gene, encoding tetracycline resistance by ribosomal protection, into plasmid pTGFP2, which contains a transcriptional fusion between a tetracycline regulated promoter and the green fluorescent...

  14. Tetracycline Antibiotics and Resistance.

    Science.gov (United States)

    Grossman, Trudy H

    2016-04-01

    Tetracyclines possess many properties considered ideal for antibiotic drugs, including activity against Gram-positive and -negative pathogens, proven clinical safety, acceptable tolerability, and the availability of intravenous (IV) and oral formulations for most members of the class. As with all antibiotic classes, the antimicrobial activities of tetracyclines are subject to both class-specific and intrinsic antibiotic-resistance mechanisms. Since the discovery of the first tetracyclines more than 60 years ago, ongoing optimization of the core scaffold has produced tetracyclines in clinical use and development that are capable of thwarting many of these resistance mechanisms. New chemistry approaches have enabled the creation of synthetic derivatives with improved in vitro potency and in vivo efficacy, ensuring that the full potential of the class can be explored for use against current and emerging multidrug-resistant (MDR) pathogens, including carbapenem-resistant Enterobacteriaceae, MDR Acinetobacter species, and Pseudomonas aeruginosa. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  15. Detection of antibiotic resistance and tetracycline resistance genes in Enterobacteriaceae isolated from the Pearl rivers in South China

    Energy Technology Data Exchange (ETDEWEB)

    Tao Ran [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Su Haochang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhou Hongwei [Department of Environmental Health, School of Public Health and Tropical Medicine, Southern Medical University, 1838 North Guangzhou Street, Baiyun District, Guangzhou 510515 (China); Sidhu, Jatinder P.S. [CSIRO Land and Water, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia QLD 4067 (Australia)

    2010-06-15

    This study investigated antibiotic resistance profiles and tetracycline resistance genes in Enterobacteriaceae family isolates from the Pearl rivers. The Enterobacteriaceae isolates were tested for susceptibility to seven antibiotics ampicillin, chloramphenicol, ciprofloxacin, levofloxacin, sulphamethoxazole/trimethoprim, tetracycline and trimethoprim. In Liuxi reservoir, with an exception to ampicillin resistant strains (11%) no other antibiotic resistance bacterial strains were detected. However, multiple drug resistance in bacterial isolates from the other sites of Pearl rivers was observed which is possibly due to sewage discharge and input from other anthropogenic sources along the rivers. Four tetracycline resistance genes tet A, tet B, tet C and tet D were detected in the isolates from the rivers. The genes tet A and tet B were widely detected with the detection frequencies of 43% and 40% respectively. Ciprofloxacin and levofloxacin resistant enteric bacteria were also isolated from the pig and duck manures which suggest a wider distribution of human specific drugs in the environment. This investigation provided a baseline data on antibiotic resistance profiles and tetracycline resistance genes in the Pearl rivers delta. - High rates of antibiotic resistance in Enterobacteriaceae from river water are attributed to wastewater contamination.

  16. Molecular Identification and Quantification of Tetracycline and Erythromycin Resistance Genes in Spanish and Italian Retail Cheeses

    Science.gov (United States)

    Flórez, Ana Belén; Alegría, Ángel; Delgado, Susana

    2014-01-01

    Large antibiotic resistance gene pools in the microbiota of foods may ultimately pose a risk for human health. This study reports the identification and quantification of tetracycline- and erythromycin-resistant populations, resistance genes, and gene diversity in traditional Spanish and Italian cheeses, via culturing, conventional PCR, real-time quantitative PCR (qPCR), and denaturing gradient gel electrophoresis (DGGE). The numbers of resistant bacteria varied widely among the antibiotics and the different cheese varieties; in some cheeses, all the bacterial populations seemed to be resistant. Up to eight antibiotic resistance genes were sought by gene-specific PCR, six with respect to tetracycline, that is, tet(K), tet(L), tet(M), tet(O), tet(S), and tet(W), and two with respect to erythromycin, that is, erm(B) and erm(F). The most common resistance genes in the analysed cheeses were tet(S), tet(W), tet(M), and erm(B). The copy numbers of these genes, as quantified by qPCR, ranged widely between cheeses (from 4.94 to 10.18log⁡10/g). DGGE analysis revealed distinct banding profiles and two polymorphic nucleotide positions for tet(W)-carrying cheeses, though the similarity of the sequences suggests this tet(W) to have a monophyletic origin. Traditional cheeses would therefore appear to act as reservoirs for large numbers of many types of antibiotic resistance determinants. PMID:25302306

  17. Distribution of tetracycline resistance genes in anaerobic treatment of waste sludge: The role of pH in regulating tetracycline resistant bacteria and horizontal gene transfer.

    Science.gov (United States)

    Huang, Haining; Chen, Yinguang; Zheng, Xiong; Su, Yinglong; Wan, Rui; Yang, Shouye

    2016-10-01

    Although pH value has been widely regarded as an important factor that affects resource recovery of waste sludge, the potential influence of diverse pHs on the distribution of tetracycline resistance genes (TRGs) during sludge anaerobic treatment is largely unknown. Here we reported that in the range of pH 4-10, 0.58-1.18 log unit increase of target TRGs was observed at pH 4, compared with that at pH 7, while 0.70-1.31 log unit further removal were obtained at pH 10. Mechanism study revealed that varied pHs not only altered the community structures of tetracycline resistant bacteria (TRB), but also changed their relative abundances, benefitting the propagation (acidic pHs) or attenuation (alkaline pHs) of TRB. Further investigation indicated that the amount and gene-possessing abilities of key genetic vectors for horizontal TRGs transfer were greatly promoted at acidic pHs but restricted under alkaline conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Tetracycline resistance genes persist in soil amended with cattle feces independently from chlortetracycline selection pressure

    Czech Academy of Sciences Publication Activity Database

    Kyselková, Martina; Kotrbová, Lucie; Bhumibhamon, G.; Chroňáková, Alica; Jirout, Jiří; Vrchotová, Naděžda; Schmitt, H.; Elhottová, Dana

    2015-01-01

    Roč. 81, February (2015), s. 259-265 ISSN 0038-0717 R&D Projects: GA ČR GAP504/10/2077; GA MŠk(CZ) EE2.3.30.0032; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:60077344 ; RVO:67179843 Keywords : antibiotic resistance * cattle feces * chlortetracycline * grassland soil * tetracycline resistance genes * intI1 gene Subject RIV: EE - Microbiology, Virology; CE - Biochemistry (UEK-B) Impact factor: 4.152, year: 2015

  19. Rapid startup of thermophilic anaerobic digester to remove tetracycline and sulfonamides resistance genes from sewage sludge.

    Science.gov (United States)

    Xu, Rui; Yang, Zhao-Hui; Wang, Qing-Peng; Bai, Yang; Liu, Jian-Bo; Zheng, Yue; Zhang, Yan-Ru; Xiong, Wei-Ping; Ahmad, Kito; Fan, Chang-Zheng

    2018-01-15

    Spread of antibiotic resistance genes (ARGs) originating from sewage sludge is highlighted as an eminent health threat. This study established a thermophilic anaerobic digester using one-step startup strategy to quickly remove tetracycline and sulfonamides resistance genes from sewage sludge. At least 20days were saved in the startup period from mesophilic to thermophilic condition. Based on the results of 16S rDNA amplicons sequencing and predicted metagenomic method, the successful startup largely relied on the fast colonization of core thermophilic microbial population (e.g. Firmicutes, Proteobacteria, Actinobacteria). Microbial metabolic gene pathways for substrate degradation and methane production was also increased by one-step mode. In addition, real-time quantitative PCR approach revealed that most targeted tetracycline and sulfonamides resistance genes ARGs (sulI, tetA, tetO, tetX) were substantially removed during thermophilic digestion (removal efficiency>80%). Network analysis showed that the elimination of ARGs was attributed to the decline of their horizontal (intI1 item) and vertical (potential hosts) transfer-related elements under high-temperature. This research demonstrated that rapid startup thermophilic anaerobic digestion of wastewater solids would be a suitable technology for reducing quantities of various ARGs. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Occurrence of tetracycline-resistant fecal coliforms and their resistance genes in an urban river impacted by municipal wastewater treatment plant discharges.

    Science.gov (United States)

    Zhang, Chong-Miao; Du, Cong; Xu, Huan; Miao, Yan-Hui; Cheng, Yan-Yan; Tang, Hao; Zhou, Jin-Hong; Wang, Xiao-Chang

    2015-01-01

    Antibiotic resistance of fecal coliforms in an urban river poses great threats to both human health and the environment. To investigate the occurrence and distribution of antibiotic resistant bacteria in an urban river, water samples were collected from the Chanhe River in Xi'an, China. After membrane filtration of water samples, the tetracycline resistance rate of fecal coliforms and their resistance genes were detected by plating and polymerase chain reaction (PCR), respectively. We found that fecal coliforms were generally resistant to tetracycline and saw average resistance rates of 44.7%. The genes tetA and tetB were widely detected, and their positive rate was 60%-100% and 40%-90%, respectively. We found few strains containing tetC, tetK, tetQ and tetX, and we did not identify any strains containing tetG, tetM or tetO. The prevalence of tetA and tetB over other genes indicated that the main mechanism for resistance to tetracycline is by changes to the efflux pump. Our analysis of the types and proportion of tetracycline resistance genes in the Chanhe River at locations upstream and downstream of the urban center suggests that the increased number of tetracycline-resistant fecal coliforms and spatial variation of tetracycline resistance genes diversity were related to municipal wastewater treatment plant discharge.

  1. Prevalence of tetracycline resistance genes among multi-drug resistant bacteria from selected water distribution systems in southwestern Nigeria.

    Science.gov (United States)

    Adesoji, Ayodele T; Ogunjobi, Adeniyi A; Olatoye, Isaac O; Call, Douglas R; Douglas, Douglas R

    2015-06-25

    Antibiotic resistance genes [ARGs] in aquatic systems have drawn increasing attention they could be transferred horizontally to pathogenic bacteria. Water treatment plants (WTPs) are intended to provide quality and widely available water to the local populace they serve. However, WTPs in developing countries may not be dependable for clean water and they could serve as points of dissemination for antibiotic resistant bacteria. Only a few studies have investigated the occurrence of ARGs among these bacteria including tetracycline resistance genes in water distribution systems in Nigeria. Multi-drug resistant (MDR) bacteria, including resistance to tetracycline, were isolated from treated and untreated water distribution systems in southwest Nigeria. MDR bacteria were resistant to >3 classes of antibiotics based on break-point assays. Isolates were characterized using partial 16S rDNA sequencing and PCR assays for six tetracycline-resistance genes. Plasmid conjugation was evaluated using E. coli strain DH5α as the recipient strain. Out of the 105 bacteria, 85 (81 %) and 20 (19 %) were Gram- negative or Gram- positive, respectively. Twenty-nine isolates carried at least one of the targeted tetracycline resistance genes including strains of Aeromonas, Alcaligenes, Bacillus, Klebsiella, Leucobacter, Morganella, Proteus and a sequence matching a previously uncultured bacteria. Tet(A) was the most prevalent (16/29) followed by tet(E) (4/29) and tet30 (2/29). Tet(O) was not detected in any of the isolates. Tet(A) was mostly found with Alcaligenes strains (9/10) and a combination of more than one resistance gene was observed only amongst Alcaligenes strains [tet(A) + tet30 (2/10), tet(A) + tet(E) (3/10), tet(E) + tet(M) (1/10), tet(E) + tet30 (1/10)]. Tet(A) was transferred by conjugation for five Alcaligenes and two E. coli isolates. This study found a high prevalence of plasmid-encoded tet(A) among Alcaligenes isolates, raising the possibility that this

  2. Detection and linkage to mobile genetic elements of tetracycline resistance gene tet(M) in Escherichia coli isolates from pigs

    DEFF Research Database (Denmark)

    Jurado-Rabadan, Sonia; de la Fuente, Ricardo; Ruiz-Santa-Quiteria, Jose A.

    2014-01-01

    Background: In Escherichia coli the genes involved in the acquisition of tetracycline resistance are mainly tet(A) and tet(B). In addition, tet(M) is the most common tetracycline resistance determinant in enterococci and it is associated with conjugative transposons and plasmids. Although tet(M) ...... expected. In our study, tet(M) detected in E. coli seems not to have been transferred from enterococci, although it can not be ruled out that the horizontal transfer of this gene occurred from other intestinal tract bacteria....... from pigs, as well as the detection of mobile genetic elements linked to tet(M) in E. coli and its possible transfer from enterococci. Results: tet(A) was the most frequently detected gene (87.9%) in doxycycline-resistant isolates. tet(M) was found in 13.1% E. coli isolates. The tet(M) gene......Background: In Escherichia coli the genes involved in the acquisition of tetracycline resistance are mainly tet(A) and tet(B). In addition, tet(M) is the most common tetracycline resistance determinant in enterococci and it is associated with conjugative transposons and plasmids. Although tet...

  3. Presence of erythromycin and tetracycline resistance genes in lactic acid bacteria from fermented foods of Indian origin.

    Science.gov (United States)

    Thumu, Surya Chandra Rao; Halami, Prakash M

    2012-11-01

    Lactic acid bacteria (LAB) resistant to erythromycin were isolated from different food samples on selective media. The isolates were identified as Enterococcus durans, Enterococcus faecium, Enterococcus lactis, Enterococcus casseliflavus, Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus fermentum, Pediococcus pentosaceus and Leuconostoc mesenteroides. Of the total 60 isolates, 88 % harbored the ermB gene. The efflux gene msrA was identified in E. faecium, E. durans, E. lactis, E. casseliflavus, P. pentosaceus and L. fermentum. Further analysis of the msrA gene by sequencing suggested its homology to msrC. Resistance to tetracycline due to the genes tetM, tetW, tetO, tetK and tetL, alone or in combination, were identified in Lactobacillus species. The tetracycline efflux genes tetK and tetL occurred in P. pentosaceus and Enterococcus species. Since it appeared that LAB had acquired these genes, fermented foods may be a source of antibiotic resistance.

  4. Class 1 integrons and tetracycline resistance genes in Alcaligenes, Arthrobacter, and Pseudomonas spp. isolated from pigsties and manured soil

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Sandvang, Dorthe

    2005-01-01

    The presence of tetracycline resistance (Tc-r) genes and class I integrons (in-1), and their ability to cotransfer were investigated in Tc-r gram-negative (185 strains) and gram-positive (72 strains) bacteria from Danish farmland and pigsties. The isolates belonged to the groups or species...... tet(33). No isolates contained more than one tet gene. The in-l-positive isolates were tested for resistance to selected antimicrobial agents and showed resistance to three to nine drugs. Filter-mating experiments showed cotransfer of Tc-r and class I integrons from soil isolates to Escherichia coli...... and/or Pseudomonas putida. We conclude that soil bacteria in close contact to manure or pigsty environment may thus have an important role in horizontal spread of resistance. Use of tetracyclines in food animal production may increase not only Tc-r but also multidrug resistance (caused by the presence...

  5. PCR detection of oxytetracycline resistance genes otr(A) and otr(B) in tetracycline-resistant streptomycete isolates from diverse habitats

    NARCIS (Netherlands)

    Nikolakopoulou, T; Egan, S; van Overbeek, L; Guillaume, G; Heuer, H; Wellington, EMH; van Elsas, JD; Collard, JM; Smalla, K; Karagouni, A

    2005-01-01

    A range of European habitats was screened by PCR for detection of the oxytetracycline resistance genes otr(A) and otr(B), found in the oxytetracycline-producing strain Streptomyces rimosus. Primers were developed to detect these otr genes in tetracycline-resistant (Tc-R) streptomycete isolates from

  6. Horizontal Transfer of Tetracycline Resistance Genes in the Subsurface of a Poultry Farm

    Science.gov (United States)

    You, Y.; Ward, M.; Hilpert, M.

    2008-12-01

    Concentrated animal feeding operations (CAFOs) are considered to be important man-made reservoirs of antibiotic resistant bacteria and antibiotic resistance genes. At a poultry farm, we, together with Mr.~James Doolittle from USDA, measured the apparent subsurface electrical conductivity (ECa) using a EM38 meter. The resulting ECaR) associated with the poultry farm due to the fact that tetracycline (Tc) is one of the most frequently used antibiotics in food animal production and therefore is probably used at this farm. Soil and aquifer samples were taken from the farm. TcR bacteria were detected, with higher concentrations in the top layer of soil than in the aquifer. TcR bacteria were then enriched from a soil sample, and two classes of TcR genes were detected: tet(M) genes encoding ribosomal protection proteins and tet(L) genes encoding tet efflux pumps. Sequences of the PCR products were compared to known tet(M) and tet(L) genes in GenBank using BLASTN. Phylogenetic trees were also built based on the sequence information. The tet(M) genes found in our soil sample were highly similar to those located on transposons. In a soil microcosm experiment, we used the aforementioned soil sample as incubation medium as well as genetic donor (TcR soil bacteria), and a green fluorescent strain of E. coli as a model genetic recipient to study horizontal transfer of TcR genes from soil bacteria to naïve bacteria. Concentrations of inoculated E. coli were continuously monitored for 15 days, TcR E. coli isolated, and colony PCR performed. The tet(M) genes were found to be transferred to naïve E. coli. The highest horizontal transfer ratio, 0.62 transconjugant per recipient, was observed when Tc was supplemented to a soil microcosm at a concentration of 140 μg/kg soil. Modeling is also ongoing to obtain a better understanding of this complex phenomenon.

  7. Detection of tetracycline resistance determinant tetA gene and antimicrobial resistance pattern in Escherichia coli isolates recovered from healthy layer chickens

    Directory of Open Access Journals (Sweden)

    A. Balasubramaniam

    2014-09-01

    Full Text Available Aim: The aim was to study the occurrence of tetracycline resistance determinant tetA gene, and antibacterial resistance pattern in commensal Escherichia coli recovered from healthy non-clinical layer chickens. Materials and Methods: Twenty-four cloacal swabs were obtained from 15 flocks in five different layer farms located at around Namakkal, which is a place of high-intensity layer chicken rearing in south India. Identification of E. coli was carried out by performing cultural and biochemical tests. Antimicrobial resistance test was carried out using disc diffusion method. The polymerase chain reaction employing tetAC forward and tetAC reverse primers were carried out to detect tetA gene conferring resistance to tetracycline. Result: All the collected cloacal swabs yielded E. coli. Twenty-one isolates (88% were resistant to tetracycline antibiotic in disc diffusion method. All the isolates showed resistance to more than six antibiotics, which implied existence of multidrug resistant microbiota in intestine of poultry. Only seven (29% isolates showed the presence of tetA gene indicating the involvement of either other one or more efflux gene(s, namely tetB, tetC and tetD or ribosomal protection encoded by tetM, tetO, tetQ and tetS genes than tetA gene. Conclusion: Based on the presence of tetA gene among tetracycline-resistant bacteria in healthy non-clinical food-producing animals such as layer chickens, it can be significant in human medicine as tetA gene could easily be spread to other bacteria. This kind of phenomenon can be extrapolated in transfer of resistance for other antibacterial essential for treating bacterial infections in human. We conclude that preventing the spread of antimicrobial resistance through direct or indirect contact, consumed food/feed and through the environment is empirical in reduction of failures while treating bacterial infections.

  8. Prevalence of sulfonamide and tetracycline resistance genes in drinking water treatment plants in the Yangtze River Delta, China.

    Science.gov (United States)

    Guo, Xueping; Li, Jing; Yang, Fan; Yang, Jie; Yin, Daqiang

    2014-09-15

    The occurrence and distribution of antibiotic resistance genes (ARGs) in drinking water treatment plants (DWTPs) and finished water are not well understood, and even less is known about the contribution of each treatment process to resistance gene reduction. The prevalence of ten commonly detected sulfonamide and tetracycline resistance genes, namely, sul I, sul II, tet(C), tet(G), tet(X), tet(A), tet(B), tet(O), tet(M) and tet(W) as well as 16S-rRNA genes, were surveyed in seven DWTPs in the Yangtze River Delta, China, with SYBR Green I-based real-time quantitative polymerase chain reaction. All of the investigated ARGs were detected in the source waters of the seven DWTPs, and sul I, sul II, tet(C) and tet(G) were the four most abundant ARGs. Total concentrations of ARGs belonging to either the sulfonamide or tetracycline resistance gene class were above 10(5) copies/mL. The effects of a treatment process on ARG removal varied depending on the overall treatment scheme of the DWTP. With combinations of the treatment procedures, however, the copy numbers of resistance genes were reduced effectively, but the proportions of ARGs to bacteria numbers increased in several cases. Among the treatment processes, the biological treatment tanks might serve as reservoirs of ARGs. ARGs were found in finished water of two plants, imposing a potential risk to human health. The results presented in this study not only provide information for the management of antibiotics and ARGs but also facilitate improvement of drinking water quality. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Low minimum inhibitory concentrations associated with the tetracycline-resistance gene tet(C) in Escherichia coli

    Science.gov (United States)

    Chalmers, Gabhan; Kozak, Gosia K.; Hillyer, Elizabeth; Reid-Smith, Richard J.; Boerlin, Patrick

    2010-01-01

    Twenty-eight Escherichia coli isolates from various animal and environmental sources with defined tetracycline-resistance genotypes for tet(A), tet(B), and tet(C) were tested for their susceptibility to tetracycline by means of both broth microdilution and Etest. All tet(C)-positive isolates had tetracycline minimum inhibitory concentrations clustering around an intermediate susceptibility range of 2 to 16 μg/mL. Detecting tet(C)-positive isolates by means of susceptibility testing may therefore be difficult with use of the current breakpoint for tetracycline of the Clinical and Laboratory Standards Institute guidelines. PMID:20592845

  10. Investigation of the Genetic Basis of Tetracycline Resistance in ...

    African Journals Online (AJOL)

    Chopra I, Roberts M. Tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance. Microbiol. Mol Biol Rev 2001; 65(2): 232-260. 2. Roberts MC. Update on acquired tetracycline resistance genes. FEMS Microbiol Lett 2005;. 245(2): 195-203. 3. Speer BS, Shoemaker NB, ...

  11. Detection of AdeABC efflux pump genes in tetracycline-resistant Acinetobacter baumannii isolates from burn and ventilator-associated pneumonia patients

    Directory of Open Access Journals (Sweden)

    Maryam Beheshti

    2014-01-01

    Full Text Available Purpose: Acinetobacter baumannii is the most prevalent nosocomial pathogen which have been emerged in the past three decades worldwide. The aim of this study was to assess the distribution of the AdeABC efflux pump genes, associated with tetracycline resistance in Acinetobacter baumannii isolates collected from burn infection and Ventilator Associated Pneumonia (VAP. Materials and Methods: Ninety-eight A. baumannii isolates were collected from two different hospitals in Tehran, Iran. Tetracycline susceptibility testing was performed by disk diffusion and agar dilution methods according to the CLSI guidelines. The presence of adeSR, adeB, drug efflux system genes in resistant isolates was assessed by polymerase chain reaction (PCR. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP was used as a chemical inhibitor agent to assess the contribution of AdeABC efflux pump in tetracycline resistance isolates. Results: Approximately 48% (47 out of 98 of isolates showed resistance to tetracycline which 14 (14.2% isolates were corresponded to burn infection and the remaining 33 (33.8% strains were isolated from VAP. All tetracycline resistant isolates have AdeABC in PCR assay. The reduction of tetracycline MICs by using 50 μg/ml CCCP were as follows: in 18 isolates 2-4 fold reduction in MICs, 26 isolates showed 8 fold reduction,1 isolate showed 16 fold, 1 isolate showed 32 fold and the remaining 1 isolate showed 128 fold reduction in MICs. Conclusion: The results showed significant correlation between tetracycline resistance and AdeABC efflux pump genes in resistant A. baumannii isolates.

  12. Comparison of ozone and thermal hydrolysis combined with anaerobic digestion for municipal and pharmaceutical waste sludge with tetracycline resistance genes.

    Science.gov (United States)

    Pei, Jin; Yao, Hong; Wang, Hui; Ren, Jia; Yu, Xiaohua

    2016-08-01

    Biosolids from wastewater treatment plant (WWTP) are environmental reservoirs of antibiotic resistance genes, which attract great concerns on their efficient treatments. Anaerobic digestion (AD) is widely used for sewage sludge treatment but its effectiveness is limited due to the slow hydrolysis. Ozone and thermal hydrolysis pre-treatment were employed to improve AD efficiency and reduce antibiotic-resistant genes in municipal and pharmaceutical waste sludge (MWS and PWS, respectively) in this study. Sludge solubilization achieved 15.75-25.09% and 14.85-33.92% after ozone and thermal hydrolysis, respectively. Both pre-treatments improved cumulative methane production and the enhancements were greater on PWS than MWS. Five tetracycline-resistant genes (tet(A), tet(G), tet(Q), tet(W), tet(X)) and one mobile element (intI1) were qPCR to assess pre-treatments. AD of pre-treated sludge reduced more tet genes than raw sludge for both ozonation and thermal hydrolysis in PWS and MWS. Thermal hydrolysis pre-treatment was more efficient than ozone for reduction after AD. Results of this study help support management options for reducing the spread of antibiotic resistance from biosolids. Copyright © 2016. Published by Elsevier Ltd.

  13. Distribution of tetracycline resistance genes and AmpC β-lactamase genes in representative non-urban sewage plants and correlations with treatment processes and heavy metals.

    Science.gov (United States)

    Xu, Yan-Bin; Hou, Mao-Yu; Li, Ya-Fei; Huang, Lu; Ruan, Jing-Jing; Zheng, Li; Qiao, Qing-Xia; Du, Qing-Ping

    2017-03-01

    The mixed development of livestock breeding and industry in non-urban zones is a very general phenomenon in China. Distribution of antibiotic resistance genes (ARGs) in non-urban sewage treatment systems has not been paid enough attentions. In this study, eleven tetracycline resistance genes (tetA, tetB, tetC, tetE, tetG, tetL, tetM, tetO, tetQ, tetS and tetX), four AmpC β-lactamase genes (EBC, MOX, FOX and CIT) and four heavy metals (Cu, Zn, Cd and Pb) were detected and analyzed in four non-urban sewage plants with different sewage sources and different treatment processes in Guangzhou. The results showed that tetA and tetC were the most prevalent tetracycline resistance genes with the same detection frequency of 85% and EBC was the most prevalent AmpC β-lactamase gene with a detection frequency of 75%. The relative abundance of tetracycline resistance genes was approximately 1.6 orders of magnitudes higher than that of AmpC β-lactamase genes in all samples. A/O was the most effective process for the non-urban sewage plant receiving industrial or agricultural wastewater. Sedimentation was the most key process to eliminate ARGs from liquid phase. Most ARGs were carried in excess sludge rather than effluent. Significant correlation was found between the tet gene and Zn (r = 0.881, p gene and Cu (r = 0.847, p gene and Cu (r = 0.714, p < 0.05). Therefore, the pollution of ARGs in the sewage treatment systems of non-urban zones co-polluted by heavy metals should be paid more attentions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Seasonal dynamics of tetracycline resistance gene transport in the Sumas River agricultural watershed of British Columbia, Canada.

    Science.gov (United States)

    Keen, Patricia L; Knapp, Charles W; Hall, Kenneth J; Graham, David W

    2018-02-13

    Environmental transport of contaminants that can influence the development of antibiotic resistance in bacteria is an important concern in the management of ecological and human health risks. Agricultural regions are locales where practices linked to food crop and livestock production can introduce contaminants that could alter the selective pressures for the development of antibiotic resistance in microbiota. This is important in regions where the use of animal manure or municipal biosolids as waste and/or fertilizer could influence selection for antibiotic resistance in pathogenic bacterial species. To investigate the environmental transport of contaminants that could lead to the development of antibiotic resistance in bacteria, a watershed with one of the highest levels of intensity of agricultural activity in Canada was studied; the Sumas River located 60 km east of Vancouver, British Columbia. This two-year assessment monitored four selected tetracycline resistance genes (tet(O), tet(M), tet(Q), tet(W)) and water quality parameters (temperature, specific conductivity, turbidity, suspended solids, nitrate, phosphate and chloride) at eight locations across the watershed. The tetracycline resistance genes (Tc r ) abundances in the Sumas River network ranged between 1.47 × 10 2 and 3.49 × 10 4  copies/mL and ranged between 2.3 and 6.9 copies/mL in a control stream (located far from agricultural activities) for the duration of the study. Further, Tc r abundances that were detected in the wet season months ranged between 1.3 × 10 3 and 2.29 × 10 4  copies/mL compared with dry season months (ranging between 0.6 and 31.2 copies/mL). Highest transport rates between 1.67 × 10 11 and 1.16 × 10 12  copies/s were observed in November 2005 during periods of high rainfall. The study showed that elevated concentrations of antibiotic resistance genes in the order of 10 2 -10 4  copies/mL can move through stream networks in an

  15. Distribution and diversity of tetracycline resistance genes encoding ribosomal protection proteins in Mekong river sediments in Vietnam.

    Science.gov (United States)

    Kobayashi, Takeshi; Suehiro, Fujiyo; Cach Tuyen, Bui; Suzuki, Satoru

    2007-03-01

    We investigated the distribution and diversity of tetracycline resistance genes encoding ribosomal protection proteins (RPPs) in river and channel sediments of the Mekong Delta in Vietnam. The sediment samples were taken from nine sites in the Hau River in southern Vietnam and from 1 site in a channel in Can Tho City in May 2004 using an Ekman-Birge sediment surface sampler. The RPP genes were amplified using PCR with DNA templates obtained directly from the sediments. The tet(M), tet(S), and tet(W) genes were detected by PCR in most sediment samples. Denaturing gradient gel electrophoresis analysis of these genes and sequencing of the resulting bands showed that tet(S) and tet(W) had only one genotype each, but that tet(M) had at least two, which were tentatively called type 1 and type 2. Type 1 tet(M) was identical to the gene encoded in various plasmids and transposons of gram-positive and gram-negative bacteria, and type 2tet(M) was similar to the gene encoded in Tn1545 of Enterococcus faecalis (99% identity, 170 bp/171 bp). This study showed that various RPP genes were widely distributed in the river and channel sediments of the Mekong Delta.

  16. Occurrence of sulfonamide-, tetracycline-, plasmid-mediated quinolone- and macrolide-resistance genes in livestock feedlots in Northern China.

    Science.gov (United States)

    Mu, Quanhua; Li, Jin; Sun, Yingxue; Mao, Daqing; Wang, Qing; Luo, Yi

    2015-05-01

    Antibiotic resistance genes (ARGs) in livestock feedlots deserve attention because they are prone to transfer to human pathogens and thus pose threats to human health. In this study, the occurrence of 21 ARGs, including tetracycline (tet)-, sulfonamide (sul)-, plasmid-mediated quinolone (PMQR)- and macrolide-resistance (erm) genes were investigated in feces and adjacent soils from chicken, swine, and cattle feedlots in Northern China. PMQR and sul ARGs were the most prevalent and account for over 90.0 % of the total ARGs in fecal samples. Specifically, PMQR genes were the most prevalent, accounting for 59.6 % of the total ARGs, followed by sul ARGs (34.2 %). The percentage of tet ARGs was 3.4 %, and erm ARGs accounted for only 1.9 %. Prevalence of PMQR and sul ARGs was also found in swine and cattle feces. The overall trend of ARG concentrations in feces of different feeding animals was chicken > swine > beef cattle in the studied area. In soils, sul ARGs had the highest concentration and account for 71.1 to 80.2 % of the total ARGs, which is possibly due to the widely distributed molecular carriers (i.e., class one integrons), facilitating sul ARG propagation. Overall, this study provides integrated profiles of various types of ARGs in livestock feedlots and thus provides a reference for the management of antibiotic use in livestock farming.

  17. Behavior of tetracycline and sulfamethazine with corresponding resistance genes from swine wastewater in pilot-scale constructed wetlands.

    Science.gov (United States)

    Liu, Lin; Liu, Yu-Hong; Wang, Zhen; Liu, Chao-Xiang; Huang, Xu; Zhu, Ge-Fu

    2014-08-15

    Four pilot-scale constructed wetlands (free water surface, SF; horizontal subsurface flow, HSF; vertical subsurface flows with different water level, VSF-L and VSF-H) were operated to assess their ability to remove sulfamethazine (SMZ) and tetracycline (TC) from wastewaters, and to investigate the abundance level of corresponding resistance genes (sulI, sulII, tetM, tetW and tetO) in the CWs. The results indicated that CWs could significantly reduce the concentration of antibiotics in wastewater, and the mass removal rate range of SMZ and TC were respectively 11%-95% and 85%-95% in the four systems on the basis of hydraulic equilibrium; further relatively high removal rate was observed in VSF with low water level. Seasonal condition had a significant effect on SMZ removal in the CWs (especially SMZ in SF), but TC removal in VSFs were not considered to have statistically significant differences in winter and summer. At the end period, the relative abundances of target genes in the CWs showed obvious increases compared to initial levels, ranging from 2.98 × 10(-5) to 1.27 × 10(-1) for sul genes and 4.68 × 10(-6) to 1.54 × 10(-1) for tet genes after treatment, and those abundances showed close relation to both characteristic of wastewater and configuration of CWs. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Bacterial Resistance to the Tetracyclines and Antimicrobial ...

    African Journals Online (AJOL)

    Tetracycline antibiotics are known to exhibit their therapeutic activity against a wide range of gram-positive and gram-negative bacteria, chlamydia, mycoplasmas, rickettsiae and protozoan parasites. Moreover, during the past few decades, many bacterial groups have been exhibiting tetracycline antibiotics resistance, as a ...

  19. Diversity of the tetracycline resistance gene tet(M) and identification of Tn916- and Tn5801-like (Tn6014) transposons in Staphylococcus aureus from humans and animals

    DEFF Research Database (Denmark)

    de Vries, Lisbeth Elvira; Christensen, H.; Skov, R. L.

    2009-01-01

    to S. aureus recipients. S. aureus of human origin contained diverse tet(M) located on Tn916- and Tn5801-like (Tn6014) transposons, and S. aureus of animal origin contained Tn916-like tet(M) genes. This suggests that conjugative transposition plays an important role in the evolution and horizontal...... spread of tet(M) in S. aureus. This is the first study showing horizontal transfer of Tn5801 (Tn6014).......To analyse the sequence diversity of the tetracycline resistance gene tet(M) in Staphylococcus aureus from humans and animals and to determine mobile elements associated with tet(M) in S. aureus. In total, 205 tetracycline-resistant isolates were screened for tet(M) by PCR. tet(M) genes were...

  20. Characterization of transferable tetracycline resistance genes in Enterococcus faecalis isolated from raw food

    DEFF Research Database (Denmark)

    Wilcks, Andrea; Andersen, Sigrid Rita; Licht, Tine Rask

    2005-01-01

    '. For the 238 resistant isolates identified, the ability to transfer the resistant phenotype to a given recipient in vitro was investigated. New and interesting observations were that the tet(L) resistance determinant was more readily transferred than tet(M), and that the presence of Tn916-like elements known...... to encode tet(M) did not correlate with increased transferability of the resistant phenotype....

  1. Characterization of microbial community and antibiotic resistance genes in activated sludge under tetracycline and sulfamethoxazole selection pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ma, Haijun; Ren, Hongqiang; Xu, Ke; Ding, Lili

    2016-11-15

    To investigate the microbial community characteristics, antibiotic resistance genes (ARGs), and bioreactor effluent quality change under tetracycline (TC) and sulfamethoxazole (SMX) selection pressure, sequencing batch reactors (SBRs) were used with environmentally relevant concentration and high-level of TC and SMX concentrations (0, 5 ppb, 50 ppb and 10 ppm). Chemical oxygen demand (COD) and ammonia nitrogen (NH{sub 4}{sup +}−N) removals appeared unchanged (p > 0.05) with 5 and 50 ppb, but decreased significantly with 10 ppm (p < 0.05). Extracellular polymeric substances (EPS) concentrations increased significantly with increasing TC or SMX concentrations (p < 0.05). High-throughput 16S rRNA gene sequencing results suggested that Proteobacteria, Actinobacteria and Bacteroidetes were the three most abundant phyla in sludge samples. The Actinobacteria percentages increased with increasing TC or SMX concentration, while Proteobacteria and Bacteroidetes decreased. The microbial diversity achieved its maximum at 5 ppb and decreased with higher concentrations. The total ARGs abundances in sludge increased with addition of TC or SMX, and the higher relative abundances were in the order of sul1 > tetG > sul2 > tetA > intI1 > tetS > tetC. Pearson correlation analysis showed most ARGs (tetA, tetC, tetG, tetK, tetM, sul1) were significantly correlated with intI1 (p < 0.01). - Highlights: • COD and NH{sub 4}{sup +}−N removals significantly decrease under 10 ppm TC or SMX. • Activated sludge EPS concentrations increase with increasing TC or SMX concentrations. • TC and SMX affect the microbial community diversity of activated sludge. • Actinobacteria abundances increase with increase of TC or SMX concentration. • ARGs abundance increases with addition of TC or SMX.

  2. Assessment of Tetracyclines Residues and Tetracycline Resistant Bacteria in Conventional and Organic Baby Foods.

    Science.gov (United States)

    Guarddon, Mónica; Miranda, José M; Vázquez, Beatriz I; Cepeda, Alberto; Franco, Carlos M

    2015-07-22

    Children are very vulnerable to bacterial infections and they are sometimes subject to antimicrobials for healing. The presence of resistance genes may counteract effects of antimicrobials. This work has thereby compared the amount of tetracycline resistance genes, tet (A) and tet (B), between conventional and organic meat-based or vegetable-based baby foods and used the quantification of these genes to assess the presence of tetracycline residues in these samples. Counts of bacteria harboring the tet (A) gene were higher than those containing tet (B), and there was no difference between the organic and the conventional samples. Samples with detectable amounts of tetracycline residues were also positive for the presence of tet genes, and when the presence of the genes was not detected, the samples were also negative for the presence of residues. The percentages of tetracycline residues were higher in organic samples than in conventional ones. It cannot be concluded that organic formulas are safer than conventional ones for the studied parameters.

  3. Assessment of Tetracyclines Residues and Tetracycline Resistant Bacteria in Conventional and Organic Baby Foods

    Directory of Open Access Journals (Sweden)

    Mónica Guarddon

    2015-07-01

    Full Text Available Children are very vulnerable to bacterial infections and they are sometimes subject to antimicrobials for healing. The presence of resistance genes may counteract effects of antimicrobials. This work has thereby compared the amount of tetracycline resistance genes, tet(A and tet(B, between conventional and organic meat-based or vegetable-based baby foods and used the quantification of these genes to assess the presence of tetracycline residues in these samples. Counts of bacteria harboring the tet(A gene were higher than those containing tet(B, and there was no difference between the organic and the conventional samples. Samples with detectable amounts of tetracycline residues were also positive for the presence of tet genes, and when the presence of the genes was not detected, the samples were also negative for the presence of residues. The percentages of tetracycline residues were higher in organic samples than in conventional ones. It cannot be concluded that organic formulas are safer than conventional ones for the studied parameters.

  4. Genetic Basis of Tetracycline Resistance in Bifidobacterium animalis subsp lactis

    NARCIS (Netherlands)

    Gueimonde, M.; Florez, A.B.; Hoek, van A.H.A.M.; Stuer-Lauridsen, B.; Stroman, P.; Reyes-Gavilan, de los C.G.; Margolles, A.

    2010-01-01

    All strains of Bifidobacterium animalis subsp. lactis described to date show medium level resistance to tetracycline. Screening of 26 strains from a variety of sources revealed the presence of tet(W) in all isolates. A transposase gene upstream of tet(W) was found in all strains, and both genes were

  5. The identification of a tetracycline resistance gene tet(M), on a Tn916-like transposon, in the Bacillus cereus group

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Jensen, Lars Bogø; Givskov, Michael Christian

    2002-01-01

    In order to investigate whether resistance genes present in bacteria in manure could transfer to indigenous soil bacteria, resistant isolates belonging to the Bacillus cereus group (Bacillus cereus, Bacillus anthracis and Bacillus thuringiensis) were isolated from farm soil (72 isolates) and manure...... (12 isolates) samples. These isolates were screened for tetracycline resistance genes (tet(K), tet(L), tet(M), tet(O), tet(S) and tet(T)). Of 88 isolates examined, three (3.4%) isolates carried both tet(M) and tet(L) genes, while four (4.5%) isolates carried the tet(L) gene. Eighty-one (92.......1%) isolates did not contain any of the tested genes. All tet(M) positive isolates carried transposon Tn916 and could transfer this mobile DNA element to other Gram-positive bacteria....

  6. Toxicity of tetracyclines and tetracycline degradation products to environmentally relevant bacteria, including selected tetracycline-resistant bacteria

    DEFF Research Database (Denmark)

    Halling-Sørensen, B.; Sengeløv, G.; Tjørnelund, J.

    2002-01-01

    Tetracyclines used in veterinary therapy invariably will find their way as parent compound and degradation products to the agricultural field. Major degradation products formed due to the limited stability of parent tetracyclines (tetracycline, chlortetracycline, and oxytetracycline) in aqueous...... solution were theoretically identified at various environmental conditions, such as pH, presence of chelating, metals, and fight. Their potency was assessed on sludge bacteria, tetracycline-sensitive soil bacteria, and tetracycline-resistant strains. Several of the degradation products had potency...... at the same concentration level as tetracycline, chlortetracycline, and oxytetracycline on both the sludge and the tetracycline-sensitive soil bacteria. Further, both 5a,6-anhydrotetracychne and 5a,6-anhydrochlortetracycline had potency on tetracycline-resistant bacteria supporting a mode of action different...

  7. The frequency of tetracycline resistance genes co-detected with respiratory pathogens: a database mining study uncovering descriptive trends throughout the United States.

    Science.gov (United States)

    Huff, Matthew D; Weisman, David; Adams, John; Li, Song; Green, Jessica; Malone, Leslie L; Clemmons, Scott

    2014-08-25

    The Center for Disease Control and Prevention (CDC) indicates that one of the largest problems threatening healthcare includes antibiotic resistance. Tetracycline, an effective antibiotic that has been in use for many years, is becoming less successful in treating certain pathogens. To better understand the temporal patterns in the growth of antibiotic resistance, patient diagnostic test records can be analyzed. Data mining methods including frequent item set mining and association rules via the Apriori algorithm were used to analyze results from 80,241 Target Enriched Multiplex-PCR (TEM-PCR) reference laboratory tests. From the data mining results, five common respiratory pathogens and their co-detection rates with tetracycline resistance genes (TRG) were further analyzed and organized according to year, patient age, and geography. From 2010, all five pathogens were associated with at least a 24% rise in co-detection rate for TRGs. Patients from 0-2 years old exhibited the lowest rate of TRG co-detection, while patients between 13-50 years old displayed the highest frequency of TRG co-detection. The Northeastern region of the United States recorded the highest rate of patients co-detected with a TRG and a respiratory pathogen. Along the East-west gradient, the relative frequency of co-detection between TRGs and respiratory pathogens decreased dramatically. Significant trends were uncovered regarding the co-detection frequencies of TRGs and respiratory pathogens over time. It is valuable for the field of public health to monitor trends regarding the spread of resistant infectious disease, especially since tetracycline continues to be utilized a treatment for various microbial infections. Analyzing large datasets containing TEM-PCR results for co-detections provides valuable insights into trends of antibiotic resistance gene expression so that the effectiveness of first-line treatments can be continuously monitored.

  8. Tetracycline consumption and occurrence of tetracycline resistance in Salmonella typhimurium phage types from Danish pigs

    DEFF Research Database (Denmark)

    Emborg, Hanne-Dorthe; Vigre, Håkan; Jensen, Vibeke Frøkjær

    2007-01-01

    The aims of the present study were to investigate at the farm-owner level the effect of prescribed tetracycline consumption in pigs and different Salmonella Typhimurium phage types on the probability that the S. Typhimurium was resistant to tetracycline. In this study, 1,307 isolates were included......, originating from 877 farm owners, and data were analyzed using logistic regression. The analysis showed that both the S. Typhimurium phage type (p resistance. In particular, the phage type...... was strongly associated with tetracycline resistance. A further analysis of data from the Danish Integrated Antimicrobial Resistance Monitoring and Research Programme (DANMAP) indicates that the tetracycline-susceptible phage types only slowly become tetracycline resistant, although tetracycline consumption...

  9. Monitoring and source tracking of tetracycline resistance genes in lagoons and groundwater adjacent to swine production facilities over a 3-year period

    Science.gov (United States)

    Koike, S.; Krapac, I.G.; Oliver, H.D.; Yannarell, A.C.; Chee-Sanford, J. C.; Aminov, R.I.; Mackie, R.I.

    2007-01-01

    To monitor the dissemination of resistance genes into the environment, we determined the occurrence of tetracycline resistance (Tcr) genes in groundwater underlying two swine confinement operations. Monitoring well networks (16 wells at site A and 6 wells at site C) were established around the lagoons at each facility. Groundwater (n = 124) and lagoon (n = 12) samples were collected from the two sites at six sampling times from 2000 through 2003. Total DNA was extracted, and PCR was used to detect seven Tcr genes [tet(M), tet(O), tet(Q), tet(W), tet(C), tet(H), and tet(Z)]. The concentration of Tcr genes was quantified by real-time quantitative PCR. To confirm the Tcr gene source in groundwater, comparative analysis of tet(W) gene sequences was performed on groundwater and lagoon samples. All seven Tcr genes were continually detected in groundwater during the 3-year monitoring period at both sites. At site A, elevated detection frequency and concentration of Tcr genes were observed in the wells located down-gradient of the lagoon. Comparative analysis of tet(W) sequences revealed that the impacted groundwater contained gene sequences almost identical (99.8% identity) to those in the lagoon, but these genes were not found in background libraries. Novel sequence clusters and unique indigenous resistance gene pools were also found in the groundwater. Thus, antibiotic resistance genes in groundwater are affected by swine manure, but they are also part of the indigenous gene pool. Copyright ?? 2007, American Society for Microbiology. All Rights Reserved.

  10. The tetracycline resistance determinant Tet 39 and the sulphonamide resistance gene sulII are common among resistant Acinetobacter spp. isolated from integrated fish farms in Thailand

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Petersen, Andreas

    2007-01-01

    genes [tet(A), tet(B), tet(H), tet(M) and tet(39)] and class II integrons by PCR. One hundred and thirty-four of these isolates were also sulphonamide resistant and these isolates were screened for sulphonamide resistance genes (sulII and sulIII) as well as class I integrons. Plasmid extraction...

  11. Autoclave treatment of pig manure does not reduce the risk of transmission and transfer of tetracycline resistance genes in soil: successive determinations with soil column experiments.

    Science.gov (United States)

    Kang, Yijun; Gu, Xian; Hao, Yangyang; Hu, Jian

    2016-03-01

    The increasing use of antibiotics, especially tetracycline, in livestock feed adversely affects animal health and ecological integrity. Therefore, approaches to decrease this risk are urgently needed. High temperatures facilitate antibiotic degradation; whether this reduces transmission risk and transfer of tetracycline-resistant bacteria (TRBs) and tetracycline resistance genes (TRGs) in soil remains unknown. Successive experiments with soil columns evaluated the effects of autoclaving pig manure (APM) on soil TRB populations and TRGs over time at different soil depths. The data showed sharp increases in TRB populations and TRGs in each subsoil layer of PM (non-APM) and APM treatments within 30 days, indicating that TRBs and TRGs transferred rapidly. The level of TRBs in the upper soil layers was approximately 15-fold higher than in subsoils. TRBs were not dependent on PM and APM levels, especially in the late phase. Nevertheless, higher levels of APM led to rapid expansion of TRBs as compared to PM. Moreover, temporal changes in TRB frequencies in total culturable bacteria (TCBs) were similar to TRBs, indicating that the impact of PM or APM on TRBs was more obvious than for TCBs. TRBs were hypothesized to depend on the numbers of TRGs and indigenous recipient bacteria. In the plough layer, five TRGs (tetB, tetG, tetM, tetW, and tetB/P) existed in each treatment within 150 days. Selective pressure of TC may not be a necessary condition for the transfer and persistence of TRGs in soil. High temperatures might reduce TRBs in PM, which had minimal impact on the transmission and transfer of TRGs in soil. Identifying alternatives to decrease TRG transmission remains a major challenge.

  12. Analysis of the prevalence of tetracycline resistance genes in clinical isolates of Enterococcus faecalis and Enterococcus faecium in a Japanese hospital.

    Science.gov (United States)

    Nishimoto, Yutaka; Kobayashi, Nobumichi; Alam, Mohammed Mahbub; Ishino, Masaho; Uehara, Nobuyuki; Watanabe, Naoki

    2005-01-01

    Prevalence of seven tetracycline resistance (TC(R)) genes--tet(L), tet(M), tet(K), tet(O), tet(S), tet(T), and tet(U)--which are known to be distributed to gram-positive cocci was analyzed for 224 Enterococcus faecalis and 46 Enterococcus faecium clinical isolates obtained in a Japanese hospital. Any of the TC(R) genes was detected in 75.9% of all the enterococcal strains. The tet(M) was detected at highest rates in both E. faecalis (75.0%) and E. faecium (69.6%), followed by tet(L), which was harbored in 6.7% of E. faecalis isolates and 30.4% of E. faecium isolates. The tet(O), tet(S), and tet(T) were detected in E. faecalis at low frequencies mostly associated with tet(M), while tet(K) and tet(U) were not detected. Nucleotide sequences of tet(S) from E. faecalis strains were identical to that reported in Listeria monocytogenes. Sequences of tet(O) from two E. faecalis strains were almost identical to each other and also to those from Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus mutans, Campylobacter jejuni, and Campylobacter coli, although minor sequence divergence was observed. The tet(T), which had been reported only in Streptococcus pyogenes, was found in five E. faecalis strains. Sequence of the enterococcal tet(T) differed from that of S. pyogenes by only four nucleotides (four amino acids) and showed high sequence identity (99.8%, amino acid level). Enterococcal strains with any one TC(R) gene or those with two TC(R) genes showed generally similar MICs of tetracyclines, and no evident difference in resistance level was observed.

  13. A Functional Metagenomic Analysis of Tetracycline Resistance in Cheese Bacteria

    Directory of Open Access Journals (Sweden)

    Ana B. Flórez

    2017-05-01

    Full Text Available Metagenomic techniques have been successfully used to monitor antibiotic resistance genes in environmental, animal and human ecosystems. However, despite the claim that the food chain plays a key role in the spread of antibiotic resistance, metagenomic analysis has scarcely been used to investigate food systems. The present work reports a functional metagenomic analysis of the prevalence and evolution of tetracycline resistance determinants in a raw-milk, blue-veined cheese during manufacturing and ripening. For this, the same cheese batch was sampled and analyzed on days 3 and 60 of manufacture. Samples were diluted and grown in the presence of tetracycline on plate count milk agar (PCMA (non-selective and de Man Rogosa and Sharpe (MRS agar (selective for lactic acid bacteria, LAB. DNA from the cultured bacteria was then isolated and used to construct four fosmid libraries, named after the medium and sampling time: PCMA-3D, PCMA-60D, MRS-3D, and MRS-60D. Clones in the libraries were subjected to restriction enzyme analysis, PCR amplification, and sequencing. Among the 300 fosmid clones analyzed, 268 different EcoRI restriction profiles were encountered. Sequence homology of their extremes clustered the clones into 47 groups. Representative clones of all groups were then screened for the presence of tetracycline resistance genes by PCR, targeting well-recognized genes coding for ribosomal protection proteins and efflux pumps. A single tetracycline resistance gene was detected in each of the clones, with four such resistance genes identified in total: tet(A, tet(L, tet(M, and tet(S. tet(A was the only gene identified in the PCMA-3D library, and tet(L the only one identified in the PCMA-60D and MRS-60D libraries. tet(M and tet(S were both detected in the MRS-3D library and in similar numbers. Six representative clones of the libraries were sequenced and analyzed. Long segments of all clones but one showed extensive homology to plasmids from Gram

  14. Environmental Macrolide-Lincosamide-Streptogramin and Tetracycline Resistant Bacteria

    Directory of Open Access Journals (Sweden)

    Marilyn C Roberts

    2011-03-01

    Full Text Available Bacteria can become resistant to antibiotics by mutation, transformation and/or acquisition of new genes which are normally associated with mobile elements (plasmids, transposons, and integrons. Mobile elements are the main driving force in horizontal gene transfer between strains, species and genera and are responsible for the rapid spread of particular elements throughout a bacterial community and between ecosystems. Today, antibiotic resistant bacteria are widely distributed throughout the world and have even been isolated from environments that are relatively untouched by human civilization. In this review macrolides, lincosamides, streptogramins, and tetracycline resistance genes and bacteria will be discussed with an emphasis on the resistance genes which are unique to environmental bacteria which are defined for this review as species and genera that are primarily found outside of humans and animals.

  15. Tetracycline resistance in semi-arid agricultural soils under long-term swine effluent application.

    Science.gov (United States)

    Popova, Inna E; Josue, Rosemarie D R; Deng, Shiping; Hattey, Jeffory A

    2017-05-04

    Annually, millions pounds of antibiotics are released unmetabolized into environment along with animal wastes. Accumulation of antibiotics in soils could potentially induce the persistence of antibiotic resistant bacteria. Antibiotics such as tetracyclines and tetracycline-resistant bacteria have been previously detected in fields fertilized with animal manure. However, little is known about the accumulation of tetracyclines and the development of tetracycline resistance in semi-arid soils. Here we demonstrate that continuous land application with swine effluent, containing trace amounts of chlortetracycline, does not necessarily induce tetracycline resistance in soil bacteria. Based on the testing of more than 3,000 bacteria isolated from the amended soils, we found no significant increase in the occurrence and level of chlortetracycline resistant bacteria in soils after 15 years of continuous swine effluent fertilization. To account for a possible transfer of tetracycline-resistant bacteria originated from the swine effluent to soils, we analyzed two commonly found tetracycline resistant genes, tet(O) and tet(M), in the swine effluent and fertilized soils. Both genes were present in the swine effluent, however, they were not detectable in soils applied with swine effluent. Our data demonstrate that agronomic application of manure from antibiotic treated swine effluent does not necessarily result in the development of antibiotic bacterial resistance in soils. Apparently, concentrations of chlortetracycline present in manure are not significant enough to induce the development of antibiotic bacterial resistance.

  16. Novel tetracycline resistance determinant isolated from an environmental strain of Serratia marcescens.

    Science.gov (United States)

    Thompson, Stuart A; Maani, Elizabeth V; Lindell, Angela H; King, Catherine J; McArthur, J Vaun

    2007-04-01

    Resistances to tetracycline and mercury were identified in an environmental strain of Serratia marcescens isolated from a stream highly contaminated with heavy metals. As a step toward addressing the mechanisms of coselection of heavy metal and antibiotic resistances, the tetracycline resistance determinant was cloned in Escherichia coli. Within the cloned 13-kb segment, the tetracycline resistance locus was localized by deletion analysis and transposon mutagenesis. DNA sequence analysis of an 8.0-kb region revealed a novel gene [tetA(41)] that was predicted to encode a tetracycline efflux pump. Phylogenetic analysis showed that the TetA(41) protein was most closely related to the Tet(39) efflux protein of Acinetobacter spp. yet had less than 80% amino acid identity with known tetracycline efflux pumps. Adjacent to the tetA(41) gene was a divergently transcribed gene [tetR(41)] predicted to encode a tetracycline-responsive repressor protein. The tetA(41)-tetR(41) intergenic region contained putative operators for TetR(41) binding. The tetA(41) and tetR(41) promoters were analyzed using lacZ fusions, which showed that the expression of both the tetA(41) and tetR(41) genes exhibited TetR(41)-dependent regulation by subinhibitory concentrations of tetracycline. The apparent lack of plasmids in this S. marcescens strain, as well as the presence of metabolic genes adjacent to the tetracycline resistance locus, suggested that the genes were located on the S. marcescens chromosome and may have been acquired by transduction. The cloned Tet 41 determinant did not confer mercury resistance to E. coli, confirming that Tet 41 is a tetracycline-specific efflux pump rather than a multidrug transporter.

  17. Effect of red mud addition on tetracycline and copper resistance genes and microbial community during the full scale swine manure composting.

    Science.gov (United States)

    Wang, Rui; Zhang, Junya; Sui, Qianwen; Wan, Hefeng; Tong, Juan; Chen, Meixue; Wei, Yuansong; Wei, Dongbin

    2016-09-01

    Swine manure has been considered as the reservoir of antibiotic resistance genes (ARGs). Composting is one of the most suitable technologies for treating livestock manures, and red mud was proved to have a positive effect on nitrogen conservation during composting. This study investigated the abundance of eight tetracycline and three copper resistance genes, the bacterial community during the full scale swine manure composting with or without addition of red mud. The results showed that ARGs in swine manure could be effectively removed through composting (reduced by 2.4log copies/g TS), especially during the thermophilic phase (reduced by 1.5log copies/g TS), which the main contributor might be temperature. Additionally, evolution of bacterial community could also have a great influence on ARGs. Although addition of red mud could enhance nitrogen conservation, it obviously hindered removal of ARGs (reduced by 1.7log copies/g TS) and affected shaping of bacterial community during composting. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Effects of chlortetracycline and copper on tetracyclines and copper resistance genes and microbial community during swine manure anaerobic digestion.

    Science.gov (United States)

    Wang, Rui; Chen, Meixue; Feng, Feng; Zhang, Junya; Sui, Qianwen; Tong, Juan; Wei, Yuansong; Wei, Dongbin

    2017-08-01

    As antibiotic and heavy metals are over used in the livestock industry, animal manure is a reservoir of antibiotic resistance genes (ARGs). Anaerobic digestion has been reported to have the potential to reduce ARGs. However, few studies investigated whether reduction of ARGs would be affected by different external pressures including antibiotics and heavy metals during anaerobic digestion. The purpose of this study was thus to investigate effects of both chlortetracycline (CTC) and Cu on reduction of ARGs, heavy metal resistance genes (HMRGs) and mobile genetic elements (MGEs) during the swine manure anaerobic digestion. The results showed that the predominant ARGs (tetO, tetW, tetX, tetL) could be effectively reduced (approximately 1.00 log copies/g TS) through mesophilic anaerobic digestion. Microbial community evolution was the main driver. It was interesting that Treponema might indicate the termination of anaerobic digestion and compete with ARGs host bacteria. Addition of CTC, Cu and CTC+Cu affected microbial community change and hindered removal of ARGs, especially, CTC+Cu seriously affected Treponema and ARGs during anaerobic digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Tetracycline

    Science.gov (United States)

    ... tetracycline. Do not take tetracycline with food, especially dairy products such as milk, yogurt, cheese, and ice ... swelling unusual bleeding or bruising chest pain a return of fever, sore throat, chills, or other signs ...

  20. Lack of doxycycline antimalarial prophylaxis impact on Staphylococcus aureus tetracycline resistance.

    Science.gov (United States)

    Mende, Katrin; Beckius, Miriam L; Zera, Wendy C; Yu, Xin; Li, Ping; Tribble, David R; Murray, Clinton K

    2016-10-01

    There is concern that susceptibility of Staphylococcus aureus to tetracyclines may decrease due to use of antimalarial prophylaxis (doxycycline). We examined characteristics related to tetracycline resistance, including doxycycline exposure, in S. aureus isolates collected via admission surveillance swabs and inpatient clinical cultures from United States military personnel injured during deployment (June 2009-January 2012). Tetracycline class resistance was determined using antimicrobial susceptibility testing. The first S. aureus isolate from 168 patients were analyzed, of which 38 (23%) isolates were resistant to tetracyclines (class). Tetracycline-resistant isolates had a higher proportion of resistance to clindamycin (P=0.019) compared to susceptible isolates. There was no significant difference in tetracycline resistance between isolates collected from patients with and without antimalarial prophylaxis; however, significantly more isolates had tet(M) resistance genes in the doxycycline exposure group (P=0.031). Despite 55% of the patients receiving doxycycline as antimalarial prophylaxis, there was no association with resistance to tetracyclines. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Incidence, distribution, and spread of tetracycline resistance determinants and integron-associated antibiotic resistance genes among motile aeromonads from a fish farming environment

    DEFF Research Database (Denmark)

    Schmidt, Anja S.; Bruun, Morten Sichlau; Dalsgaard, Inger

    2001-01-01

    A collection of 313 motile aeromonads isolated at Danish rainbow trout farms was analyzed to identify some of the genes involved in high levels of antimicrobial resistance found in a previous field trial (A. S. Schmidt, M. S. Bruun, I. Dalsgaard, K. Pedersen, and J. L. Larsen, Appl. Environ....... Microbiol. 66:4908-4915, 2000), the predominant resistance phenotype (37%) being a combined oxytetracycline (OTC) and sulphadiazine/trimethoprim resistance. Combined sulphonamide/trimethoprim resistance (135 isolates) appeared closely related to the presence of a class 1 integron (141 strains). Among...... the isolates containing integrons, four different combinations of integrated resistance gene cassettes occurred, in all cases including a dihydrofolate reductase gene and a downstream aminoglycoside resistance insert (87 isolates) and occasionally an additional chlor-amphenicol resistance gene cassette (31...

  2. Various pAQU plasmids possibly contribute to disseminate tetracycline resistance gene tet(M) among marine bacterial community.

    Science.gov (United States)

    Nonaka, Lisa; Maruyama, Fumito; Onishi, Yuki; Kobayashi, Takeshi; Ogura, Yoshitoshi; Hayashi, Tetsuya; Suzuki, Satoru; Masuda, Michiaki

    2014-01-01

    Emergence of antibiotic-resistant bacteria in the aquaculture environment is a significant problem for disease control of cultured fish as well as in human public health. Conjugative mobile genetic elements (MGEs) are involved in dissemination of antibiotic resistance genes (ARGs) among marine bacteria. In the present study, we first designed a PCR targeting traI gene encoding essential relaxase for conjugation. By this new PCR, we demonstrated that five of 83 strains isolated from a coastal aquaculture site had traI-positive MGEs. While one of the five strains that belonged to Shewanella sp. was shown to have an integrative conjugative element of the SXT/R391 family (ICEVchMex-like), the MGEs of the other four strains of Vibrio spp. were shown to have the backbone structure similar to that of previously described in pAQU1. The backbone structure shared by the pAQU1-like plasmids in the four strains corresponded to a ~100-kbp highly conserved region required for replication, partition and conjugative transfer, suggesting that these plasmids constituted "pAQU group." The pAQU group plasmids were shown to be capable of conjugative transfer of tet(M) and other ARGs from the Vibrio strains to E. coli. The pAQU group plasmid in one of the examined strains was designated as pAQU2, and its complete nucleotide sequence was determined and compared with that of pAQU1. The results revealed that pAQU2 contained fewer ARGs than pAQU1 did, and most of the ARGs in both of these plasmids were located in the similar region where multiple transposases were found, suggesting that the ARGs were introduced by several events of DNA transposition into an ancestral plasmid followed by drug selection in the aquaculture site. The results of the present study indicate that the "pAQU group" plasmids may play an important role in dissemination of ARGs in the marine environment.

  3. Various pAQU plasmids possibly contribute to disseminate tetracycline resistance gene tet(M among marine bacterial community

    Directory of Open Access Journals (Sweden)

    Lisa eNonaka

    2014-05-01

    Full Text Available Emergence of antibiotic-resistant bacteria in the aquaculture environment is a significant problem for disease control of cultured fish in as well as in human public health. Conjugative mobile genetic elements (MGEs are involved in dissemination of antibiotic resistance genes (ARGs among marine bacteria. In the present study, we first designed a PCR targeting traI gene encoding essential relaxase for conjugation. By this new PCR, we demonstrated that five of 83 strains isolated from a coastal aquaculture site had traI-positive MGEs. While one of the five strains that belonged to Shewanella sp. was shown to have an integrative conjugative element of the SXT/R391 family (ICEVchMex, the MGEs of the other four strains of Vibrio spp. were shown to have the backbone structure similar to that of previously described in pAQU1. The backbone structure shared by the pAQU1-like MGEs in the four strains corresponded to a ~100-kbp highly conserved region required for replication, partition and conjugative transfer, suggesting that these MGEs are plasmids that constitute pAQU group. The pAQU group plasmids were shown to be capable of conjugative transfer of tet(M and other ARGs from the Vibrio strains to E. coli. The pAQU group plasmid in one of the examined strains was designated as pAQU2, and its complete nucleotide sequence was determined and compared with that of pAQU1. The results revealed that pAQU2 contained fewer ARGs than pAQU1 did, and most of the ARGs in both of these plasmids were located in the similar region where multiple transposases were found, suggesting that the ARGs were introduced by several events of DNA transposition into an ancestral plasmid followed by drug selection in the aquaculture site. The results of the present study indicate that the pAQU group plasmids may play an important role in dissemination of ARGs in the marine environment.

  4. Size-related bacterial diversity and tetracycline resistance gene abundance in the air of concentrated poultry feeding operations.

    Science.gov (United States)

    Gao, Min; Jia, Ruizhi; Qiu, Tianlei; Han, Meilin; Wang, Xuming

    2017-01-01

    Concentrated animal-feeding operations (CAFOs) are considered a source of airborne human pathogens and antibiotic resistance genes. Although bacterial abundance and diversity have been well studied, limited information on the size distribution of bioaerosols has prevented a clear understanding of the health effects of exposure to bioaerosols from CAFOs. Here, different sizes of particles were sampled from the inside and outside of atmospheric environments of layer and broiler feeding operations using 8-stage Andersen samplers. The quantitative real-time polymerase chain reaction (qPCR) and 16S rDNA-based sequencing were used to analyze the characteristics of biological abundance and diversity, respectively, according to size. The results indicated that size-related differences occurred in terms of airborne bacterial richness, diversity, and concentration at poultry-feeding operations. The richness of biological genera in the urban atmospheric environment was lower than in concentrated poultry-feeding operations. The biological diversity of airborne bacterial genera, including genera associated with potential pathogens, varied according to size. The bacterial lineages of bioaerosols present in the 7 size stages for layers clustered apart from those for broilers, suggesting that the type of poultry house is a more important factor than the particle size in shaping the microbial communities. In most cases, the concentrations of the 16S rDNA, Escherichia coli, tetW, and tetL genes increased as the particle size increased, with the geometric mean diameters varying from 4.7 to 5.8 μm. These results regarding the size-related differences in the diversity and abundance of bioaerosols will facilitate a better understanding of the potential health impact on both poultry and humans working in such environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Investigation of the Genetic Basis of Tetracycline Resistance in ...

    African Journals Online (AJOL)

    Purpose: To determine the prevalence and genetic basis of tetracycline resistance in Staphylococcus aureus. Methods: One hundred and thirty (130) clinical isolates of S. aureus were collected from Khyber Teaching Hospital, Peshawar, Pakistan. Susceptibility to antibiotics (doxycycline, tetracycline and minocycline) was ...

  6. Prevalence and diversity of tetracycline resistant lactic acid bacteria and their tet genes along the process line of fermented dry sausages.

    Science.gov (United States)

    Gevers, Dirk; Masco, Liesbeth; Baert, Leen; Huys, Geert; Debevere, Johan; Swings, Jean

    2003-06-01

    In order to study the prevalence and diversity of tetracycline resistant lactic acid bacteria (Tc(r) LAB) along the process line of two different fermented dry sausage (FDS) types, samples from the raw meat, the meat batter and the fermented end product were analysed quantitatively and qualitatively by using a culture-dependent approach. Both the diversity of the tet genes and their bacterial hosts in the different stages of FDS production were determined. Quantitative analysis showed that all raw meat components of both FDS types (FDS-01 and FDS-08) contained a subpopulation of Tc(r) LAB, and that for FDS-01 no Tc(r) LAB could be recovered from the samples after fermentation. Qualitative analysis of the Tc(r) LAB subpopulation in FDS-08 included identification and typing of Tc(r) LAB isolates by (GTG)5-PCR fingerprinting, plasmid profiling, protein profiling and a characterization of the resistance by PCR detection of tet genes. Two remarks can be made when the results of this analysis for the different samples are compared. (i) The taxonomic diversity of Tc(r) LAB varies along the process line, with a higher diversity in the raw meat (lactococci, lactobacilli, streptococci, and enterococci), and a decrease after fermentation (only lactobacilli). (ii) Also the genetic diversity of the tet genes varies along the process line. Both tet(M) and tet(S) were found in the raw meat, whereas only tet(M) was found after fermentation. A possible relationship was found between the disappearing of species other than lactobacilli and tet(S), because tet(S) was only found in lacotocci, enterococci, and streptococci. These data suggest that fermented dry sausages are among those food products that can serve as vehicles for Tc(r) LAB and that the raw meat already contains a subpopulation of these bacteria. Whether these results reflect the transfer of resistant bacteria or of bacterial resistance genes from animals to man via the food chain is difficult to ascertain and may

  7. Association Between Tetracycline Consumption and Tetracycline Resistance in Escherichia coli from Healthy Danish Slaughter Pigs

    DEFF Research Database (Denmark)

    Vieira, Antonio; Houe, Hans; Wegener, Henrik Caspar

    2009-01-01

    It has been recognized that exposure to antimicrobial agents can exert a selective pressure for the emergence of antimicrobial resistance. The objective of this study was to investigate an association between the probability of isolating a tetracycline-resistant Escherichia coli isolate from...... the intestinal tract of healthy pigs and patterns of tetracycline Consumption in the herds of origin, together with other risk factors. Data oil antimicrobial resistance, antimicrobial consumption, and pig herd demographics were obtained from different Danish surveillance programs. Descriptive statistics were...... performed for the risk factors in relation to the susceptibility status. Logistic regression analysis was performed to identify risk factors with significant effect on the log odds of tetracycline resistance of E. coli isolates. The model showed that an increase in the interval between last prescription...

  8. Tetracycline Antibiotics: Mode of Action, Applications, Molecular Biology, and Epidemiology of Bacterial Resistance

    Science.gov (United States)

    Chopra, Ian; Roberts, Marilyn

    2001-01-01

    Tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. They are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. The first tetracycline-resistant bacterium, Shigella dysenteriae, was isolated in 1953. Tetracycline resistance now occurs in an increasing number of pathogenic, opportunistic, and commensal bacteria. The presence of tetracycline-resistant pathogens limits the use of these agents in treatment of disease. Tetracycline resistance is often due to the acquisition of new genes, which code for energy-dependent efflux of tetracyclines or for a protein that protects bacterial ribosomes from the action of tetracyclines. Many of these genes are associated with mobile plasmids or transposons and can be distinguished from each other using molecular methods including DNA-DNA hybridization with oligonucleotide probes and DNA sequencing. A limited number of bacteria acquire resistance by mutations, which alter the permeability of the outer membrane porins and/or lipopolysaccharides in the outer membrane, change the regulation of innate efflux systems, or alter the 16S rRNA. New tetracycline derivatives are being examined, although their role in treatment is not clear. Changing the use of tetracyclines in human and animal health as well as in food production is needed if we are to continue to use this class of broad-spectrum antimicrobials through the present century. PMID:11381101

  9. Abundances of tetracycline, sulphonamide and beta-lactam antibiotic resistance genes in conventional wastewater treatment plants (WWTPs) with different waste load

    DEFF Research Database (Denmark)

    Laht, Mailis; Karkman, Antti; Voolaid, Veiko

    2014-01-01

    Antibiotics and antibiotic resistant bacteria enter wastewater treatment plants (WWTPs), an environment where resistance genes can potentially spread and exchange between microbes. Several antibiotic resistance genes (ARGs) were quantified using qPCR in three WWTPs of decreasing capacity located ...

  10. 16S rRNA mutation-mediated tetracycline resistance in Helicobacter pylori

    NARCIS (Netherlands)

    M.M. Gerrits (Monique); M.R. de Zoete; N.L.A. Arents (Niek); E.J. Kuipers (Ernst); J.G. Kusters (Johannes)

    2002-01-01

    textabstractMost Helicobacter pylori strains are susceptible to tetracycline, an antibiotic commonly used for the eradication of H. pylori. However, an increase in incidence of tetracycline resistance in H. pylori has recently been reported. Here the mechanism of tetracycline

  11. Antimicrobial susceptibility and tetracycline resistance determinant genotyping of Gallibacterium anatis

    DEFF Research Database (Denmark)

    Bojesen, Anders M.; Vazquez, Maria E.; Bager, Ragnhild J.

    2011-01-01

    . Multidrug resistance (resistance towards≥three drugs) was observed for 65% of the field strains and only two strains were susceptible to all compounds. Most prominently, resistance to tetracycline and sulfamethoxazole was observed in 92% and 97% of the field strains, respectively. For comparison...... these figures were 67% and 42%, respectively, for the reference strains.Genotyping of tetracycline resistance determinants was performed with primers specific for tet(A–E, H, K–M, O). Strains positive for tet(B), tet(H) and tet(L) were identified, however, in 20 out of 49 tetracycline resistant strains...... no determinant was identified.This is the first study to determine the antimicrobial susceptibility of Gallibacterium anatis by MIC revealing that multidrug resistance is very common among G. anatis field isolates. tet(B) was by far the most common determinant identified but future work should aim at identifying...

  12. Phenotypic and genotypic characteristics of tetracycline resistant Acinetobacter baumannii isolates from nosocomial infections at Tehran hospitals

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Maleki

    2014-01-01

    Full Text Available   Objective(s: To date, the most important genes responsible for tetracycline resistance among Acinetobacter baumannii isolates have been identified as tet A and tet B. This study was carried out to determine the rate of resistance to tetracycline and related antibiotics, and mechanisms of resistance.   Materials and Methods: During the years 2010 and 2011, a total of 100 A. baumannii isolates were recovered from patients in different hospitals of Tehran, Iran. Antimicrobial susceptibility to tetracycline, minocycline, doxicycline and tigecycline was evaluated by E-test. Polymerase chain reaction (PCR of the tet A and tet B genes was performed using specific primers, after which the isolates were subjected to Repetitive Extragenic Palindromic-PCR (PCR to identify the major genotypes. Results: Of all isolates, 89% were resistant to tetracycline (MIC50 = 32 μg/ml, MIC90 = 512 μg/ml. Minocycline with the resistant rate of 35% (MIC50 = 16 μg/ml, MIC90 =32 μg/ml and doxicycline with the resistant rate of 25% (MIC50 = 16 μg/ml, MIC90= 32 μg/ml have a good activity against A. baumannii isolates. All isolates were sensitive to tigecycline. Frequencies of tet B and tet A genes and coexistence of tet A and tet B among the isolates resistant to tetracycline, were 87.6%, 2.2% and 1.1%, respectively. Distribution of REP-types among A. baumannii isolates was types A (40%, B (30%, C (10%, D (5% and E (5%.   Conclusion: It seems that tet A and tet B genes play an important role in the induction of resistance towards tetracyclines used in this study. It is suggested that further studies focus on other antimicrobial drugs and combinations in order to achieve a successful therapy against multi drug resistance (MDR A. baumannii strains in Iran.

  13. Identification and prevalence of tetracycline resistance in enterococci isolated from poultry in Ilishan, Ogun State, Nigeria

    Directory of Open Access Journals (Sweden)

    Funmilola A Ayeni

    2016-01-01

    Full Text Available Background: Tetracycline is one of the most frequently used antibiotics in Nigeria both for human and animal infections because of its cheapness and ready availability. The use of tetracycline in animal husbandry could lead to horizontal transfer of tet genes from poultry to human through the gut microbiota, especially enterococci. Therefore, this study is designed to identify different enterococcal species from poultry feces in selected farms in Ilishan, Ogun State, Nigeria, determine the prevalence of tetracycline resistance/genes and presence of IS256 in enterococcal strains. MaterialsandMethods: Enterococci strains were isolated from 100 fresh chicken fecal samples collected from seven local poultry farms in Ilishan, Ogun State, Nigeria. The strains were identified by partial sequencing of 16S rRNA genes. Antibiotic susceptibility of the isolates to vancomycin, erythromycin, tetracycline, gentamicin, amoxycillin/claulanate, and of loxacin were performed by disc diffusion method. Detection of tet, erm, and van genes and IS256 insertion element were done by polymerase chain reaction amplification. Results: Sixty enterococci spp. were identified comprising of Enterococcus faecalis 33 (55%, Enterococcus casseliflavus 21 (35%, and Enterococcus gallinarium 6 (10%. All the isolates were resistant to erythromycin (100%, followed by tetracycline (81.67%, amoxicillin/clavulanic acid (73.33%, ofloxacin (68.33%, vancomycin (65%, and gentamicin (20%. None of the enterococcal spp. harbored the van and erm genes while tet(M was detected among 23% isolates and is distributed mostly among E. casseliflavus. IS256 elements were detected only in 33% of E. casseliflavus that were also positive for tet(M gene. Conclusion: This study provides evidence that tetracycline resistance gene is present in the studied poultry farms in Ilishan, Ogun State, Nigeria and underscores the need for strict regulation on tetracycline usage in poultry farming in the studied

  14. Resistance to the tetracyclines and macrolide-lincosamide-streptogramin group of antibiotics and its genetic linkage - a review.

    Science.gov (United States)

    Marosevic, Durdica; Kaevska, Marija; Jaglic, Zoran

    2017-06-12

    An excessive use of antimicrobial agents poses a risk for the selection of resistant bacteria. Of particular interest are antibiotics that have large consumption rates in both veterinary and human medicine, such as the tetracyclines and macrolide-lincosamide-streptogramin (MLS) group of antibiotics. A high load of these agents increases the risk of transmission of resistant bacteria and/or resistance determinants to humans, leading to a subsequent therapeutic failure. An increasing incidence of bacteria resistant to both tetracyclines and MLS antibiotics has been recently observed. This review summarizes the current knowledge on different tetracycline and MLS resistance genes that can be linked together on transposable elements.

  15. Comparison of metals and tetracycline as selective agents for development of tetracycline resistant bacterial communities in agricultural soil

    DEFF Research Database (Denmark)

    Song, Jianxiao; Rensing, Christopher; Holm, Peter Engelund

    2017-01-01

    Environmental selection of antibiotic resistance may be caused by either antibiotic residues or coselecting agents. Using a strictly controlled experimental design, we compared the ability of metals (Cu or Zn) and tetracycline to (co)select for tetracycline resistance in bacterial communities. Soil...... microcosms were established by amending agricultural soil with known levels of Cu, Zn, or tetracycline known to represent commonly used metals and antibiotics for pig farming. Soil bacterial growth dynamics and bacterial community-level tetracycline resistance were determined using the [(3)H......]leucine incorporation technique, whereas soil Cu, Zn, and tetracycline exposure were quantified by a panel of whole-cell bacterial bioreporters. Tetracycline resistance increased significantly in soils containing environmentally relevant levels of Cu (≥365 mg kg(-1)) and Zn (≥264 mg kg(-1)) but not in soil spiked...

  16. Prevalence of Chlamydia trachomatis, Ureaplasma spp., Mycoplasma genitalium and Mycoplasma hominis among outpatients in central Greece: absence of tetracycline resistance gene tet(M over a 4-year period study

    Directory of Open Access Journals (Sweden)

    A. Ikonomidis

    2016-01-01

    Full Text Available A total of 301 men and women attending local urologists and gynaecologists in the state of Thessaly, central Greece, were tested for Chlamydia trachomatis, Ureaplasma spp., Mycoplasma genitalium and Mycoplasma hominis DNA. Investigation of the tet(M gene, which confers tetracycline resistance in these genera, was also performed. Low incidence of C. trachomatis and Mycoplasma spp. as well as high prevalence of Ureaplasma spp., especially among women, were found. The tet(M gene was absent in all cases, notably in a region where doxycycline administration remains the first therapeutic option unless special medical conditions direct otherwise.

  17. Tetracycline inducible gene manipulation in serotonergic neurons.

    Directory of Open Access Journals (Sweden)

    Tillmann Weber

    Full Text Available The serotonergic (5-HT neuronal system has important and diverse physiological functions throughout development and adulthood. Its dysregulation during development or later in adulthood has been implicated in many neuropsychiatric disorders. Transgenic animal models designed to study the contribution of serotonergic susceptibility genes to a pathological phenotype should ideally allow to study candidate gene overexpression or gene knockout selectively in serotonergic neurons at any desired time during life. For this purpose, conditional expression systems such as the tet-system are preferable. Here, we generated a transactivator (tTA mouse line (TPH2-tTA that allows temporal and spatial control of tetracycline (Ptet controlled transgene expression as well as gene deletion in 5-HT neurons. The tTA cDNA was inserted into a 196 kb PAC containing a genomic mouse Tph2 fragment (177 kb by homologous recombination in E. coli. For functional analysis of Ptet-controlled transgene expression, TPH2-tTA mice were crossed to a Ptet-regulated lacZ reporter line (Ptet-nLacZ. In adult double-transgenic TPH2-tTA/Ptet-nLacZ mice, TPH2-tTA founder line L62-20 showed strong serotonergic β-galactosidase expression which could be completely suppressed with doxycycline (Dox. Furthermore, Ptet-regulated gene expression could be reversibly activated or inactivated when Dox was either withdrawn or added to the system. For functional analysis of Ptet-controlled, Cre-mediated gene deletion, TPH2-tTA mice (L62-20 were crossed to double transgenic Ptet-Cre/R26R reporter mice to generate TPH2-tTA/Ptet-Cre/R26R mice. Without Dox, 5-HT specific recombination started at E12.5. With permanent Dox administration, Ptet-controlled Cre-mediated recombination was absent. Dox withdrawal either postnatally or during adulthood induced efficient recombination in serotonergic neurons of all raphe nuclei, respectively. In the enteric nervous system, recombination could not be detected. We

  18. Presence of Chlamydia trachomatis and Mycoplasma spp., but not Neisseria gonorrhoeae and Treponema pallidum, in women undergoing an infertility evaluation: high prevalence of tetracycline resistance gene tet(M).

    Science.gov (United States)

    Li, Min; Zhang, Xiaomei; Huang, Ke; Qiu, Haixiang; Zhang, Jilei; Kang, Yuan; Wang, Chengming

    2017-11-17

    Chlamydia trachomatis, Mycoplasma spp., Neisseria gonorrhoeae and Treponema pallidum are sexually transmitted pathogens that threaten reproductive health worldwide. In this study, vaginal swabs obtained from women (n = 133) that attended an infertility clinic in China were tested with qPCRs for C. trachomatis, Mycoplasma spp., N. gonorrhoeae, T. pallidum and tetracycline resistance genes. While none of vaginal swabs were positive for N. gonorrhoeae and T. pallidum, 18.8% (25/133) of the swabs were positive for Chlamydia spp. and 17.3% of the swabs (23/133) were positive for Mycoplasma species. All swabs tested were positive for tetracycline resistance gene tet(M) which is the most effective antibiotic for bacterial sexually transmitted infections. The qPCRs determined that the gene copy number per swab for tet(M) was 7.6 times as high as that of C. trachomatis 23S rRNA, and 14.7 times of Mycoplasma spp. 16S rRNA. In China, most hospitals do not detect C. trachomatis and Mycoplasma spp. in women with sexually transmitted infections and fertility problems. This study strongly suggests that C. trachomatis and Mycoplasma spp. should be routinely tested in women with sexually transmitted infections and infertility in China, and that antimicrobial resistance of these organisms should be monitored. Further studies are warranted to determine the prevalences in different regions and associated risk factors.

  19. Mosaic tetracycline Genes and their Flanking Regions in Bifidobacterium thermophilum and lactobacillus johnsonii

    NARCIS (Netherlands)

    Hoek, van A.H.A.M.; Mayrhofer, S.; Domig, K.J.; Flórez, A.B.; Ammor, M.S.; Mayo, B.; Aarts, H.J.M.

    2008-01-01

    For the first time, mosaic tetracycline resistance genes were identified in Lactobacillus johnsonii and in Bifidobacterium thermophilum strains. The L. johnsonii strain investigated contains a complex hybrid gene, tet(O/W/32/O/W/O), whereas the five bifidobacterial strains possess two different

  20. Susceptibility of Escherichia coli and Enterococcus faecium isolated from pigs and broiler chickens to tetracycline degradation products and distribution of tetracycline resistance determinants in E-coli from food animals

    DEFF Research Database (Denmark)

    Sengeløv, G.; Halling-Sørensen, B.; Aarestrup, Frank Møller

    2003-01-01

    One hundred Escherichia coli isolates from diseased and healthy pigs, cattle and broiler chickens were screened for the presence of tetracycline resistance genes tet(A), (13), (C), (D) or (E). The tet(A) gene was the most abundant (71% of the 100 isolates) followed by tet(B) (25%). The predominan...... and 18 tetracycline resistant and 10 sensitive Enterococcus faecium to tetracyclines and tetracycline degradation products was determined. The resistant isolates showed reduced resistance to anhydrotetracycline, 4-epi-anhydrotetracycline, anhydrochlortetracycline and 4-epi......-anhydrochlortetracycline. In general both the tetracycline resistant and susceptible E. faecium were more susceptible to the compounds tested than E. coli. (C) 2003 Elsevier B.V.. All rights reserved....

  1. Novel plasmid conferring kanamycin and tetracycline resistance in turkey-derived Campylobacter jejuni strain 11601MD

    Science.gov (United States)

    In Campylobacter spp., resistance to the antibiotics kanamycin and tetracycline is frequently associated with plasmid-borne genes. However, relatively few plasmids of Campylobacter jejuni have been fully characterized to date. A novel plasmid (p11601MD; 44,095 bp.) harboring tet(O) was identified in...

  2. The role of zero valent iron on the fate of tetracycline resistance genes and class 1 integrons during thermophilic anaerobic co-digestion of waste sludge and kitchen waste.

    Science.gov (United States)

    Gao, Pin; Gu, Chaochao; Wei, Xin; Li, Xiang; Chen, Hong; Jia, Hanzhong; Liu, Zhenhong; Xue, Gang; Ma, Chunyan

    2017-03-15

    Activated sludge has been identified as a potential significant source of antibiotic resistance genes (ARGs) to the environment. Anaerobic digestion is extensively used for sludge stabilization and resource recovery, and represents a crucial process for controlling the dissemination of ARGs prior to land application of digested sludge. The objective of this study is to investigate the effect of zero valent iron (Fe 0 ) on the attenuation of seven representative tetracycline resistance genes (tet, tet(A), tet(C), tet(G), tet(M), tet(O), tet(W), and tet(X)), and the integrase gene intI1 during thermophilic anaerobic co-digestion of waste sludge and kitchen waste. Significant decrease (P genes was observed at Fe 0 dosage of 5 g/L, whereas no significant differences (P > 0.05) were found for all gene targets between digesters with Fe 0 dosages of 5 and 60 g/L. A first-order kinetic model favorably described the trends in concentrations of tet and intI1 gene targets during thermophilic anaerobic digestion with or without Fe 0 . Notably, tet genes encoding different resistance mechanisms behaved distinctly in anaerobic digesters, although addition of Fe 0 could enhance their reduction. The overall results of this research suggest that thermophilic anaerobic digestion with Fe 0 can be a potential alternative technology for the attenuation of tet and intI1 genes in waste sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The Gut as Reservoir of Antibiotic Resistance: Microbial Diversity of Tetracycline Resistance in Mother and Infant

    DEFF Research Database (Denmark)

    de Vries, Lisbeth Elvira; Valles, Yvonne; Agersø, Yvonne

    2011-01-01

    study using a metagenomic approach to determine the diversity of microorganisms conferring tetracycline resistance (Tc-r) in the guts of a healthy mother-infant pair one month after childbirth, and to investigate the potential for horizontal transfer and maternal transmission of Tc-r genes. Fecal fosmid...... the infant's gut. In addition, although not found in the infant metagenomic library, tet(O) and tet(W) could be detected in the uncloned DNA purified from the infant fecal sample. This is the first study to reveal the diversity of Tc-r bacteria in the human gut, to detect a likely transmission of antibiotic......The microbiota in the human gastrointestinal tract (GIT) is highly exposed to antibiotics, and may be an important reservoir of resistant strains and transferable resistance genes. Maternal GIT strains can be transmitted to the offspring, and resistances could be acquired from birth. This is a case...

  4. Effect of chlorination and ultraviolet disinfection on tetA-mediated tetracycline resistance of Escherichia coli.

    Science.gov (United States)

    Huang, Jing-Jing; Hu, Hong-Ying; Wu, Yin-Hu; Wei, Bin; Lu, Yun

    2013-02-01

    Antibiotic-resistant bacteria are an emerging threat to public health during drinking water consumption and reclaimed water reuse. Several studies have shown that the proportions of antibiotic-resistant bacteria in waters may increase when exposed to low doses of UV light or chlorine. In this study, inactivation of tetracycline-resistant Escherichia coli and antibiotic-sensitive E. coli by UV disinfection and chlorination was compared to determine the tolerance of tetracycline-resistant E. coli to UV light and chlorine, and tetracycline resistance of a tetracycline-resistant E. coli population was studied under different doses of the disinfectants. Our results showed that relative to antibiotic-sensitive E. coli, tetracycline-resistant E. coli had the same tolerance to UV light and a potentially higher tolerance to chlorination. The mortality frequency distributions of tetracycline-resistant E. coli exposed to tetracycline were shifted by both chlorination and UV disinfection. When compared to the hemi-inhibitory concentrations (IC(50)) of tetracycline-resistant E. coli with no exposure to UV or chlorination, the IC(50) of tetracycline-resistant E. coli treated with tetracycline was 40% lower when inactivation by UV light or chlorination reached 3-log but was 1.18 times greater when inactivation by chlorination reached 4.3-log. Chlorination applied to drinking water or reclaimed water treatment may increase the risk of selection for highly tetracycline-resistant E. coli. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Mini-Mu insertions in the tetracycline resistance determinant from Proteus mirabilis

    Directory of Open Access Journals (Sweden)

    Magalhães V.D.

    1997-01-01

    Full Text Available The inducible tetracycline resistance determinant isolated from Proteus mirabilis cloned into the plasmid pACYC177 was mutagenized by insertion of a mini-Mu-lac phage in order to define the regions in the cloned sequences encoding the structural and regulatory proteins. Three different types of mutants were obtained: one lost the resistance phenotype and became Lac+; another expressed the resistance at lower levels and constitutively; the third was still dependent on induction but showed a lower minimal inhibitory concentration. The mutant phenotypes and the locations of the insertions indicate that the determinant is composed of a repressor gene and a structural gene which are not transcribed divergently as are other known tetracycline determinants isolated from Gram-negative bacteria

  6. Relation between tetR and tetA expression in tetracycline resistant Escherichia coli

    National Research Council Canada - National Science Library

    Møller, Thea S B; Overgaard, Martin; Nielsen, Søren S; Bortolaia, Valeria; Sommer, Morten O A; Guardabassi, Luca; Olsen, John E

    2016-01-01

    Tetracyclines are among the most used antibiotics in livestock worldwide. Resistance is widely disseminated in Escherichia coli, where it is generally mediated by tetracycline efflux pumps, such as TetA...

  7. Relation between tetR and tetA expression in tetracycline resistant Escherichia coli

    DEFF Research Database (Denmark)

    Møller, Thea S. B.; Overgaard, Martin; Nielsen, Søren S.

    2016-01-01

    Background: Tetracyclines are among the most used antibiotics in livestock worldwide. Resistance is widely disseminated in Escherichia coli, where it is generally mediated by tetracycline efflux pumps, such as TetA. Expression of tetracycline efflux pumps is tightly controlled by the repressor Tet......R, which has been shown to be tetracycline-responsive at sub-MIC tetracycline concentrations. The objective of this study was to investigate the effects of increasing tetracycline concentrations on the growth of TetA-producing E. coli, and to determine how expression of tetA and tetR related to each other...... in different growth phases in the presence of tetracycline. Results: A tetracycline resistant E. coli strain containing tetA and tetR on the chromosome was constructed and cultured in the presence of increasing concentrations of tetracycline. Expression of tetR and tetA was measured at four time points...

  8. Changes of bacterial diversity and tetracycline resistance in sludge from AAO systems upon exposure to tetracycline pressure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Manhong, E-mail: egghmh@163.com; Qi, Fangfang; Wang, Jue; Xu, Qi; Lin, Li

    2015-11-15

    Highlights: • High-throughput sequencing was used to compare sludge bacteria with and without TC. • Bacterial diversity increased with TC addition despite of various oxygen conditions. • Total TRGs proliferated with TC addition in three kinds of sludge. • The concentration of efflux pump genes was the highest in the three groups of TRGs. - Abstract: Two lab-scale anaerobic-anoxic-oxic (AAO) systems were used to investigate the changes in tetracycline (TC) resistance and bacterial diversity upon exposure to TC pressure. High-throughput sequencing was used to detect diversity changes in microorganisms at the level of class in sludge from different bioreactors with and without TC. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the abundances of eight tetracycline resistance genes (TRGs), tetA, tetB, tetC, tetE, tetM, tetO, tetS and tetX. The results showed that the diversities of the microbial communities of anoxic, anaerobic and aerobic sludge all increased with the addition of TC. TC substantially changed the structure of the microbial community regardless of oxygen conditions. Bacteroidetes and Proteobacteria were the dominant species in the three kinds of sludge and were substantially enriched with TC pressure. In sludge with TC added, almost all target TRGs proliferated more than those in sludge without TC except tetX, which decreased in anaerobic sludge with TC addition. The concentration of efflux pump genes, tet(A–C, E), was the highest among the three groups of TRGs in the different kinds of sludge.

  9. Biochemical and molecular characterization of tetracycline-resistant Aeromonas veronii isolates from catfish.

    Science.gov (United States)

    Nawaz, Mohamed; Sung, Kidon; Khan, Saeed A; Khan, Ashraf A; Steele, Roger

    2006-10-01

    Eighty-one tetracycline-resistant Aeromonas sp. strains were isolated from farm-raised catfish. Morphological and biochemical characteristics indicated that 23 of the 81 aeromonads were Aeromonas hydrophila, 7 isolates were Aeromonas trota, 6 isolates were Aeromonas caviae, 42 isolates were Aeromonas veronii, and 3 isolates were Aeromonas jandaei. However, the AluI and MboI restriction fragment length polymorphism (RFLP) patterns of the PCR-amplified 1.4-kb 16S rRNA gene from all 81 tetracycline-resistant aeromonads from catfish were identical to the RFLP banding patterns of A. veronii ATCC 35626, indicating that all 81 isolates were strains of A. veronii. A multiplex PCR assay successfully amplified the 5 tetracycline-resistant genes (tetA to E) from the genomic DNA of all 81 isolates. The assay determined that tetE was the dominant gene occurring in 73/81 (90.0%) of the aeromonads. Plasmids (2.0 to 20 kb) were isolated from 33 of the 81 isolates. Dendrogram analysis of the SpeI pulsed-field gel electrophoresis identified 15 distinct macrorestriction patterns among the isolates. Our results indicate the need for use of 16S rRNA in the identification of Aeromonas spp. and the prevalence of catfish as a reservoir of tet genes.

  10. Fate of tetracycline resistance in synthetic livestock carcass leachate for two years.

    Science.gov (United States)

    Salcedo, Dennis Espineli; Kim, Sungpyo

    2017-02-01

    To simulate the fate of antibiotic resistance in leachate from anaerobic carcass landfill site, anaerobic reactors were set-up and their antibiotic resistance activities were monitored for 2 years. Initially, Escherichia coli DH5α with tetracycline resistance pB10 plasmid was inoculated in nutrient rich anaerobic reactors. The fate of tetracycline resistant bacteria (TRB) was tracked by analysis using culture-based method, EC50 (half maximal effective concentration), and quantitative polymerase chain reaction (qPCR). Based on the temporal pattern of EC50 during the study period, TRB continuously increased during Phase I (0-250th day), went down in Phase II (after 250th day to 500th day), and then increased again by the end of Phase III (after 500th day to the 774th day). Interestingly, pB10 plasmid accumulated in the system as the community diversities increased over time. At the end of experiment, the tetracycline resistance microbial communities were investigated by 16s RNA gene-based pyro sequencing. The results of this study indicated that leachate with high organic strength in anaerobic conditions could be an antibiotic resistant point source in several year periods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. The gut as reservoir of antibiotic resistance: microbial diversity of tetracycline resistance in mother and infant.

    Directory of Open Access Journals (Sweden)

    Lisbeth E de Vries

    Full Text Available The microbiota in the human gastrointestinal tract (GIT is highly exposed to antibiotics, and may be an important reservoir of resistant strains and transferable resistance genes. Maternal GIT strains can be transmitted to the offspring, and resistances could be acquired from birth. This is a case study using a metagenomic approach to determine the diversity of microorganisms conferring tetracycline resistance (Tc(r in the guts of a healthy mother-infant pair one month after childbirth, and to investigate the potential for horizontal transfer and maternal transmission of Tc(r genes. Fecal fosmid libraries were functionally screened for Tc(r, and further PCR-screened for specific Tc(r genes. Tc(r fosmid inserts were sequenced at both ends to establish bacterial diversity. Mother and infant libraries contained Tc(r, although encoded by different genes and organisms. Tc(r organisms in the mother consisted mainly of Firmicutes and Bacteroidetes, and the main gene detected was tet(O, although tet(W and tet(X were also found. Identical Tc(r gene sequences were present in different bacterial families and even phyla, which may indicate horizontal transfer within the maternal GIT. In the infant library, Tc(r was present exclusively in streptococci carrying tet(M, tet(L and erm(T within a novel composite transposon, Tn6079. This transposon belongs to a family of broad host range conjugative elements, implying a potential for the joint spread of tetracycline and erythromycin resistance within the infant's gut. In addition, although not found in the infant metagenomic library, tet(O and tet(W could be detected in the uncloned DNA purified from the infant fecal sample. This is the first study to reveal the diversity of Tc(r bacteria in the human gut, to detect a likely transmission of antibiotic resistance from mother to infant GITs and to indicate the possible occurrence of gene transfers among distantly related bacteria coinhabiting the GIT of the same

  12. Resistance to β-lactam and tetracycline in Campylobacter spp.isolated from broiler slaughterhouses in southern Brazil

    Directory of Open Access Journals (Sweden)

    Yuli M. Sierra-Arguello

    2015-07-01

    Full Text Available Abstract The study was carried out to screen and analyze the genetic characteristics of antimicrobial resistance in Campylobacter spp. from poultry sources. A total of 141 strains of Campylobacter isolated from samples of broilers of slaughterhouses in southern Brazil was identified by phenotypic and genotypic methods. Campylobacter isolates were evaluated for its antimicrobial susceptibility and the presence of resistance genes. The strains were investigated for antimicrobial susceptibility against two agents (ampicillin and tetracycline by disk diffusion method. PCR assay was used to confirm the specie and the presence of ampicillin (blaOXA-61, tetracycline tet(O, and the energy-dependent multi-drug efflux pump (cmeB genes. Campylobacter jejuni was the most ubiquitous; its presence was determined in 140 samples out of 141 (99.3%, whereas Campylobacter coli was found only in one of the contaminated samples (0.70%. The results obtained showed 65% and 35.5% of Campylobacter isolates resistant to β-lactams and tetracyclines, respectively. The cmeB gene responsible for multidrug resistance was detected in 26 isolates out 141 strains (18.5%. Moreover, 36 out of 141 Campylobacter strains (25.6% were found to be resistant to at least two different antimicrobia resistance markers (β-lactams and tetracyclines.

  13. Monitoring of drug resistance amplification and attenuation with the use of tetracycline-resistant bacteria during wastewater treatment

    Science.gov (United States)

    Harnisz, Monika; Korzeniewska, Ewa; Niestępski, Sebastian; Osińska, Adriana; Nalepa, Beata

    2017-11-01

    The objective of this study was to monitor changes (amplification or attenuation) in antibiotic resistance during wastewater treatment based on the ecology of tetracycline-resistant bacteria. The untreated and treated wastewater were collected in four seasons. Number of tetracycline-(TETR) and oxytetracycline-resistant (OTCR) bacteria, their qualitative composition, minimum inhibitory concentrations (MICs), sensitivity to other antibiotics, and the presence of tet (A, B, C, D, E) resistance genes were determined. TETR and OTCR counts in untreated wastewater were 100 to 1000 higher than in treated effluent. OTCR bacterial counts were higher than TETR populations in both untreated and treated wastewater. TETR isolates were not dominated by a single bacterial genus or species, whereas Aeromonas hydrophila and Aeromonas sobria were the most common in OTCR isolates. The treatment process attenuated the drug resistance of TETR bacteria and amplified the resistance of OTCR bacteria. In both microbial groups, the frequency of tet(A) gene increased in effluent in comparison with untreated wastewater. Our results also indicate that treated wastewater is a reservoir of multiple drug-resistant bacteria as well as resistance determinants which may pose a health hazard for humans and animals when released to the natural environment.

  14. Molecular basis and transferability of tetracycline resistance in Enterococcus italicus LMG 22195 from fermented milk.

    Science.gov (United States)

    Zago, Miriam; Huys, Geert; Giraffa, Giorgio

    2010-08-15

    A tetracycline-resistant Enterococcus italicus strain from fermented milk, LMG 22195, was found to contain a tet(S) gene located on a plasmid of approximately 20kb. Filter mating demonstrated that the tet(S) gene was transferable from LMG 22195 to the recipient Enterococcus faecalis JH2-2. PCR-based detection and Southern blot experiments revealed that the confirmed transconjugants acquired the tet(S)-carrying plasmid. Similar to the donor strain, transconjugants displayed a tetracycline MIC of 64 microg/ml. Results of this study suggest that E. italicus, like other enterococcal species, is able to disseminate antibiotic-resistance genes, although a more definitive proof on this statement will be provided when a higher number of strains will be tested. Because of the recent isolation of E. italicus from human clinical specimens and its concomitant presence in various dairy products, the ability of this organism to horizontally transfer tet(S) or other resistance genes may potentially pose safety concerns, especially for its possible use in food fermentations. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Two Different Tetracycline Resistance Mechanisms, Plasmid-Carried tet(L) and Chromosomally Located Transposon-Associated tet(M), Coexist in Lactobacillus sakei Rits 9▿

    Science.gov (United States)

    Ammor, Mohammed Salim; Gueimonde, Miguel; Danielsen, Morten; Zagorec, Monique; van Hoek, Angela H. A. M.; de los Reyes-Gavilán, Clara G.; Mayo, Baltasar; Margolles, Abelardo

    2008-01-01

    Lactobacillus sakei is extensively used as functional starter culture in fermented meat products. One of the safety criteria of a starter culture is the absence of potentially transferable antibiotic resistance determinants. However, tetracycline-resistant L. sakei strains have already been observed. In this paper, we show that tetracycline resistance in L. sakei Rits 9, a strain isolated from Italian Sola cheese made from raw milk, is mediated by a transposon-associated tet(M) gene coding for a ribosomal protection protein and a plasmid-carried tet(L) gene coding for a tetracycline efflux pump. pLS55, the 5-kb plasmid carrying the tet(L) gene, is highly similar to the pMA67 plasmid recently described for Paenibacillus larvae, a species pathogenic to honeybees. pLS55 could be transferred by electroporation into the laboratory strain L. sakei 23K. While the L. sakei 23K transformant containing pLS55 displayed an intermediate tetracycline resistance level (MIC, <32 μg/ml), L. sakei Rits 9, containing both tetracycline-resistant determinants, had a MIC of <256 μg/ml, suggesting that Tet L and Tet M confer different levels of resistance in L. sakei. Remarkably, in the absence of tetracycline, a basal expression of both genes was detected for L. sakei Rits 9. In addition, subinhibitory concentrations of tetracycline affected the expression patterns of tet(M) and tet(L) in different ways: the expression of tet(M) was induced only at high tetracycline concentrations, whereas the expression of tet(L) was up-regulated at lower concentrations. This is the first time that two different mechanisms conferring resistance to tetracycline are characterized for the same strain of a lactic acid bacterium. PMID:18192429

  16. Two different tetracycline resistance mechanisms, plasmid-carried tet(L) and chromosomally located transposon-associated tet(M), coexist in Lactobacillus sakei Rits 9.

    Science.gov (United States)

    Ammor, Mohammed Salim; Gueimonde, Miguel; Danielsen, Morten; Zagorec, Monique; van Hoek, Angela H A M; de Los Reyes-Gavilán, Clara G; Mayo, Baltasar; Margolles, Abelardo

    2008-03-01

    Lactobacillus sakei is extensively used as functional starter culture in fermented meat products. One of the safety criteria of a starter culture is the absence of potentially transferable antibiotic resistance determinants. However, tetracycline-resistant L. sakei strains have already been observed. In this paper, we show that tetracycline resistance in L. sakei Rits 9, a strain isolated from Italian Sola cheese made from raw milk, is mediated by a transposon-associated tet(M) gene coding for a ribosomal protection protein and a plasmid-carried tet(L) gene coding for a tetracycline efflux pump. pLS55, the 5-kb plasmid carrying the tet(L) gene, is highly similar to the pMA67 plasmid recently described for Paenibacillus larvae, a species pathogenic to honeybees. pLS55 could be transferred by electroporation into the laboratory strain L. sakei 23K. While the L. sakei 23K transformant containing pLS55 displayed an intermediate tetracycline resistance level (MIC, <32 microg/ml), L. sakei Rits 9, containing both tetracycline-resistant determinants, had a MIC of <256 microg/ml, suggesting that Tet L and Tet M confer different levels of resistance in L. sakei. Remarkably, in the absence of tetracycline, a basal expression of both genes was detected for L. sakei Rits 9. In addition, subinhibitory concentrations of tetracycline affected the expression patterns of tet(M) and tet(L) in different ways: the expression of tet(M) was induced only at high tetracycline concentrations, whereas the expression of tet(L) was up-regulated at lower concentrations. This is the first time that two different mechanisms conferring resistance to tetracycline are characterized for the same strain of a lactic acid bacterium.

  17. Real-time PCR detection of 16S rRNA novel mutations associated with Helicobacter pylori tetracycline resistance in Iran.

    Science.gov (United States)

    Dadashzadeh, Kianoosh; Milani, Morteza; Rahmati, Mohammad; Akbarzadeh, Abolfazl

    2014-01-01

    Tetracycline is an antibiotic widely used for the treatment of Helicobacter pylori infection, but its effectiveness is decreasing due to increasing bacterial resistance. The aim of this study was to investigate the occurrence of 16S rRNA mutations associated with resistance or reduced susceptibility to tetracycline of Helicobacter pylori by real-time PCR (RT-PCR) assays from culture. Tetracycline susceptibility and minimal inhibition concentration (MIC) was determined by the Epsilometer test (Etest) method. A LightCycler assay developed to detect these mutations was applied to DNA extracted from culture. The 16S rRNA of these isolates was sequenced and resistance-associated mutations were identified. From 104 isolates of H. pylori examined, 11 showed resistance to tetracycline. LightCycler assay was applied to DNA extracted from 11 tetracycline-susceptible and 11 tetracycline resistance H. pylori isolates. In our study the sequencing of the H. pylori wild types in 16 s rRNA gene were AGA 926-928 with MIC (0.016 to 0.5 μg/ml), while the sequencing and MIC for resistant were GGA and AGC, (0.75 to 1.5 μg/ml), respectively. Also we found a novel mutation in 2 strains with 84° as their melting temperatures and exhibition of an A939C mutation. We conclude that real-time PCR is an excellent method for determination of H. pylori tetracycline resistance related mutations that could be used directly on biopsy specimens.

  18. The Gut as Reservoir of Antibiotic Resistance: Microbial Diversity of Tetracycline Resistance in Mother and Infant

    DEFF Research Database (Denmark)

    de Vries, Lisbeth Elvira; Valles, Yvonne; Agersø, Yvonne

    2011-01-01

    library, Tc-r was present exclusively in streptococci carrying tet(M), tet(L) and erm(T) within a novel composite transposon, Tn6079. This transposon belongs to a family of broad host range conjugative elements, implying a potential for the joint spread of tetracycline and erythromycin resistance within...

  19. The rarely reported tet(31) tetracycline resistance determinant is common in Gallibacterium anatis

    DEFF Research Database (Denmark)

    Bojesen, Anders M.; Bager, Ragnhild J.; Ifrah, Dan

    2011-01-01

    The present investigation was undertaken to identify and characterize the tetracycline resistance determinant in 22 Gallibacterium anatis strains for which no determinant was identified using primers specific for tet(A, B, C, D, E, G, H, K, L, M, O). A recent study found tet(B) to be the most...... prevalent tetracycline resistance determinant in a larger collection of G. anatis field strains from Mexico and Denmark. However, in 41% of the tetracycline resistant strains no determinant could be assigned. Here we demonstrate that tet(31) is a common determinant in G. anatis originating from chickens...

  20. Previously undescribed plasmids recovered from activated sludge confer tetracycline resistance and phenotypic changes to Acinetobacter oleivorans DR1.

    Science.gov (United States)

    Hong, Hyerim; Ko, Hyeok-Jin; Choi, In-Geol; Park, Woojun

    2014-02-01

    We used culture-dependent and culture-independent methods to extract previously undescribed plasmids harboring tetracycline (TC) resistance genes from activated sludge. The extracted plasmids were transformed into naturally competent Acinetobacter oleivorans DR1 to recover a non-Escherichia coli-based plasmid. The transformed cells showed 80-100-fold higher TC resistance than the wild-type strain. Restriction length polymorphism performed using 30 transformed cells showed four different types of plasmids. Illumina-based whole sequencing of the four plasmids identified three previously unreported plasmids and one previously reported plasmid. All plasmids carried TC resistance-related genes (tetL, tetH), tetracycline transcriptional regulators (tetR), and mobilization-related genes. As per expression analysis, TC resistance genes were functional in the presence of TC. The recovered plasmids showed mosaic gene acquisition through horizontal gene transfer. Membrane fluidity, hydrophobicity, biofilm formation, motility, growth rate, sensitivity to stresses, and quorum sensing signals of the transformed cells were different from those of the wild-type cells. Plasmid-bearing cells seemed to have an energy burden for maintaining and expressing plasmid genes. Our data showed that acquisition of TC resistance through plasmid uptake is related to loss of biological fitness. Thus, cells acquiring antibiotic resistance plasmids can survive in the presence of antibiotics, but must pay ecological costs.

  1. Spread of Staphylococcus aureus resistant to penicillin and tetracycline within and between dairy herds

    DEFF Research Database (Denmark)

    Waage, S.; Bjorland, J.; Caugant, D. A.

    2002-01-01

    One hundred and seven bovine isolates of penicillin and tetracycline resistant Staphylococcus aureus, recovered from 25 different dairy herds in various parts of Norway, were characterized using antimicrobial susceptibility testing, multilocus enzyme electrophoresis, ribotyping, plasmid analysis...... different counties, were assigned to 6 different strains. Seven out of these 8 isolates had the same plasmid restriction profile. In conclusion, penicillin and tetracycline resistant S. aureus occurring in dairy herds in Norway mainly seems to represent one particular strain that has achieved widespread...

  2. Tetracycline Resistance in the Subsurface of a Poultry Farm: Influence of Poultry Wastes

    Science.gov (United States)

    You, Y.; Ball, W. P.; Ward, M. J.; Hilpert, M.

    2007-12-01

    Concentrated animal feeding operations (CAFOs) are considered to be important man-made reservoir of antibiotic resistant bacteria. Using the electromagnetic induction (EMI) method of geophysical characterization, we measured the apparent subsurface electrical conductivity (ECa) at a CAFO site in order to assess the movement of pollutants associated with animal waste. The map of ECa and other available data suggest that (1) soil surrounding a poultry litter storage shed is contaminated by poultry waste, (2) a contamination plume in the subsurface emanates from that shed, and (3) the development of that plume is due to groundwater flow. We focused on understanding the spread of tetracycline resistance (Tc\\tiny R), because tetracycline is one of the most frequently used antibiotics in food animal production and therefore probably used at our field site. Microbiological experiments show the presence of Tc\\tiny R bacteria in the subsurface and indicate higher concentrations in the top soil than in the aquifer. Environmental DNA was extracted to identify CAFO- associated Tc\\tiny R genes and to explore a link between the presence of Tc\\tiny R and CAFO practices. A "shot-gun" cloning approach is under development to target the most prevalent Tc\\tiny R gene. This gene will be monitored in future experiments, in which we will study the transmission of Tc\\tiny R to naive E.~coli under selective pressure of Tc. Experimental results will be used to develop a mathematical/numerical model in order to describe the transmission process and to subsequently make estimates regarding the large-scale spread of antibiotic resistance.

  3. Sequence-Based Characterization of Tn5801-Like Genomic Islands in Tetracycline-Resistant Staphylococcus pseudintermedius and Other Gram-positive Bacteria from Humans and Animals

    DEFF Research Database (Denmark)

    de Vries, Lisbeth Elvira; Hasman, Henrik; Jurado Rabadán, Sonia

    2016-01-01

    Antibiotic resistance in pathogens is often associated with mobile genetic elements, such as genomic islands (GI) including integrative and conjugative elements (ICEs). These can transfer resistance genes within and between bacteria from humans and/or animals. The aim of this study......-like GIs appear to be relatively common in tetracycline-resistant S. pseudintermedius in Denmark. Almost identical Tn5801-like GIs were identified in different Gram-positive species of pet and human origin, suggesting that horizontal transfer of these elements has occurred between S. pseudintermedius...... was to investigate whether Tn5801-like GIs carrying the tetracycline resistance gene, tet(M), are common in Staphylococcus pseudintermedius from pets, and to do an overall sequences-based characterization of Tn5801-like GIs detected in Gram-positive bacteria from humans and animals. A total of 27 tetracycline...

  4. Characterisation of penicillin and tetracycline resistance in Staphylococcus aureus isolated from bovine milk samples in Minas Gerais, Brazil.

    Science.gov (United States)

    Martini, Caroline L; Lange, Carla C; Brito, Maria Avp; Ribeiro, João B; Mendonça, Letícia C; Vaz, Eliana K

    2017-05-01

    This Regional Research Communication describes the characterisation of ampicillin, penicillin and tetracycline resistance in Staphylococcus aureus isolated from bovine subclinical mastitis in Minas Gerais State, Brazil. Ninety S. aureus isolates from bovine mastitis exhibiting phenotypic resistance to ampicillin, penicillin and/or tetracycline were selected for this study. The minimum inhibitory concentration (MIC) of each antibiotic was determined using the E-Test® and the production of beta-lactamase was determined by cefinase disks. The resistance genes blaZ, tet(K), tet(L), tet(M), and tet(O) were investigated by PCR in all of the isolates. The MIC results classified 77, 83 and 71% of the isolates as resistant to ampicillin, penicillin and tetracycline, respectively. The MIC50 and MIC90 were, respectively, 1 and 2 µg/ml for ampicillin, 0·5 and 1 µg/ml for penicillin and 32 and 64 µg/ml for tetracycline. Eighty-six per cent of beta-lactamase producing isolates were detected. Of the 90 isolates investigated, 97% amplified blaZ, 84% amplified tet(K), 9% amplified tet(L), 2% amplified tet(M) and 1% amplified tet(O). Seventy-nine isolates (88%) showed blaZ together with at least one tet gene. S. aureus isolates showed high MIC50 and MIC90 values for the three antimicrobials. The blaZ and tet(K) genes were widespread in the herds studied, and most of the isolates harboured blaZ and tet(K) concomitantly.

  5. Performance of vertical up-flow constructed wetlands on swine wastewater containing tetracyclines and tet genes.

    Science.gov (United States)

    Huang, Xu; Liu, Chaoxiang; Li, Ke; Su, Jianqiang; Zhu, Gefu; Liu, Lin

    2015-03-01

    Antibiotics and antibiotic resistance genes (ARGs) pollution in animal feeding farms received more public attention recently. Livestock wastewater contains large quantities of antibiotics and ARGs even after traditional lagoon treatment. In this study, the performance of vertical up-flow constructed wetlands (VUF-CWs) on swine wastewater containing tetracycline compounds (TCs) and tet genes was evaluated based on three aspects, TCs and tet genes removal efficiencies, residual TCs and tet genes in soils and plants, and the effect of TCs accumulation on nutrients removal and tet genes development. High removal efficiencies (69.0-99.9%) were achieved for oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) with or without OTC spiked in the influent additionally. TCs concentrations in surface soils increased at first two sampling periods and then decreased after plants were harvested. Satisfactory nutrients removal efficiencies were also obtained, but TN and NH4-N removal efficiencies were significantly negative correlated with total concentration of TCs (∑TCs) in the soils (p < 0.01). The absolute abundances of all the target genes (tetO, tetM, tetW, tetA, tetX and intI1) were greatly reduced with their log units ranging from 0.26 to 3.3. However, the relative abundances of tetO, tetM and tetX in some effluent samples were significantly higher than those in the influent (p < 0.05). The relative abundances of tet genes except for tetO were significantly correlated with ∑TCs in the soils (p < 0.05). In summary, the proposed VUF-CWs are effective alternative for the removal of TCs and tet genes. But it is of great importance to prevent large accumulation of TCs in the soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The inhibition the Tet(K) efflux pump of tetracycline resistant Staphylococcus epidermidis by essential oils from three Salvia species.

    Science.gov (United States)

    Chovanová, R; Mezovská, J; Vaverková, Š; Mikulášová, M

    2015-07-01

    The inhibition of efflux pumps is an attractive and powerful response to the emergence of bacteria resistant to antibiotics. Essential oils (EOs) from Salvia fruticosa, Salvia officinalis and Salvia sclarea reduce the minimal inhibition concentration of tetracycline, decrease efflux of antibiotic and decrease the expression of tet(K) gene in tetracycline resistant clinical isolates of Staphylococcus epidermidis. In all the cases S. fruticosa was the best one. By using checkerboard and time-killing methods, we found synergistic interactions of EOs with tetracycline. Our data from molecular and functional analyses of inhibitory effect of Salvia's essential oils, namely from S. fruticosa, on Tet(K) pump of Staphylococcus epidermidis and from modulatory studies may be the starting point for consecutive study of pharmacokinetic and pharmacodynamic parameters and their perspective use in combination therapy. Combination of antibiotic with efflux pump inhibitor would be expected to re-establish susceptibility of the bacteria to antibiotics that became no longer effective due to bacterial resistance through the efflux pumps. The inhibition of an efflux pump can potentially improve the clinical efficacy of an antibiotic and simultaneously decrease the selection of resistant mutants. © 2015 The Society for Applied Microbiology.

  7. Coselection for resistance to multiple late-generation human therapeutic antibiotics encoded on tetracycline resistance plasmids captured from uncultivated stream and soil bacteria.

    Science.gov (United States)

    Herrick, J B; Haynes, R; Heringa, S; Brooks, J M; Sobota, L T

    2014-08-01

    Transmissible plasmids captured from stream and soil bacteria conferring resistance to tetracycline in Pseudomonas were evaluated for linked resistance to antibiotics used in the treatment of human infections. Cells released from stream sediments and soils were conjugated with a rifampicin-resistant, plasmid-free Pseudomonas putida recipient and selected on tetracycline and rifampicin. Each transconjugant contained a single 50-80 kb plasmid. Resistance to 11 antibiotics, in addition to tetracycline, was determined for the stream transconjugants using a modification of the Stokes disc diffusion antibiotic susceptibility assay. Nearly half of plasmids conferred resistance to six or more antibiotics. Resistance to streptomycin, gentamicin, and/or ticarcillin was conferred by a majority of the plasmids, and resistance to additional human clinical use antibiotics such as piperacillin/tazobactam, ciprofloxacin and aztreonam was observed. MICs of 16 antibiotics for representative sediment and soil transconjugants revealed large increases, relative to the Ps. putida recipient, for 11 of 16 antibiotics tested, including the expanded spectrum antibiotics cefotaxime and ceftazidime, as well as piperacillin/tazobactam, lomefloxacin and levofloxacin. Resistance to multiple antibiotics-including those typically used in clinical Pseudomonas and enterobacterial infections-can be conferred by transmissible plasmids in streams and soils. Selective pressure exerted by the use of one antibiotic, such as the common agricultural antibiotic tetracycline, may result in the persistence of linked genes conferring resistance to important human clinical antibiotics. This may impact the spread of resistance to human use antibiotics even in the absence of direct selection. © 2014 The Society for Applied Microbiology.

  8. Molecular epidemiology, antimicrobial susceptibilities and resistance mechanisms of Streptococcus pyogenes isolates resistant to erythromycin and tetracycline in Spain (1994–2006)

    Science.gov (United States)

    2012-01-01

    Background Group A Streptococcus (GAS) causes human diseases ranging in severity from uncomplicated pharyngitis to life-threatening necrotizing fasciitis and shows high rates of macrolide resistance in several countries. Our goal is to identify antimicrobial resistance in Spanish GAS isolates collected between 1994 and 2006 and to determine the molecular epidemiology (emm/T typing and PFGE) and resistance mechanisms of those resistant to erythromycin and tetracycline. Results Two hundred ninety-five out of 898 isolates (32.8%) were erythromycin resistant, with the predominance of emm4T4, emm75T25, and emm28T28, accounting the 67.1% of the 21 emm/T types. Spread of emm4T4, emm75T25 and emm28T28 resistant clones caused high rates of macrolide resistance. The distribution of the phenotypes was M (76.9%), cMLSB (20.3%), iMLSB (2.7%) with the involvement of the erythromycin resistance genes mef(A) (89.5%), msr(D) (81.7%), erm(B) (37.3%) and erm(A) (35.9%). Sixty-one isolates were tetracycline resistant, with the main representation of the emm77T28 among 20 emm/T types. To note, the combination of tet(M) and tet(O) tetracycline resistance genes were similar to tet(M) alone reaching values close to 40%. Resistance to both antibiotics was detected in 19 isolates of 7 emm/T types, being emm11T11 and the cMLSB phenotype the most frequent ones. erm(B) and tet(M) were present in almost all the strains, while erm(A), mef(A), msr(D) and tet(O) appeared in less than half of them. Conclusions Spanish GAS were highly resistant to macrolides meanwhile showed minor resistance rate to tetracycline. A remarkable correlation between antimicrobial resistance and emm/T type was noticed. Clonal spread of emm4T4, emm75T25 and emm28T28 was the main responsable for macrolide resistance where as that emm77T28 clones were it to tetraclycline resistance. A wide variety of macrolide resistance genes were responsible for three macrolide resistance phenotypes. PMID:22998619

  9. Molecular epidemiology, antimicrobial susceptibilities and resistance mechanisms of Streptococcus pyogenes isolates resistant to erythromycin and tetracycline in Spain (1994–2006

    Directory of Open Access Journals (Sweden)

    Rubio-López Virginia

    2012-09-01

    Full Text Available Abstract Background Group A Streptococcus (GAS causes human diseases ranging in severity from uncomplicated pharyngitis to life-threatening necrotizing fasciitis and shows high rates of macrolide resistance in several countries. Our goal is to identify antimicrobial resistance in Spanish GAS isolates collected between 1994 and 2006 and to determine the molecular epidemiology (emm/T typing and PFGE and resistance mechanisms of those resistant to erythromycin and tetracycline. Results Two hundred ninety-five out of 898 isolates (32.8% were erythromycin resistant, with the predominance of emm4T4, emm75T25, and emm28T28, accounting the 67.1% of the 21 emm/T types. Spread of emm4T4, emm75T25 and emm28T28 resistant clones caused high rates of macrolide resistance. The distribution of the phenotypes was M (76.9%, cMLSB (20.3%, iMLSB (2.7% with the involvement of the erythromycin resistance genes mef(A (89.5%, msr(D (81.7%, erm(B (37.3% and erm(A (35.9%. Sixty-one isolates were tetracycline resistant, with the main representation of the emm77T28 among 20 emm/T types. To note, the combination of tet(M and tet(O tetracycline resistance genes were similar to tet(M alone reaching values close to 40%. Resistance to both antibiotics was detected in 19 isolates of 7 emm/T types, being emm11T11 and the cMLSB phenotype the most frequent ones. erm(B and tet(M were present in almost all the strains, while erm(A, mef(A, msr(D and tet(O appeared in less than half of them. Conclusions Spanish GAS were highly resistant to macrolides meanwhile showed minor resistance rate to tetracycline. A remarkable correlation between antimicrobial resistance and emm/T type was noticed. Clonal spread of emm4T4, emm75T25 and emm28T28 was the main responsable for macrolide resistance where as that emm77T28 clones were it to tetraclycline resistance. A wide variety of macrolide resistance genes were responsible for three macrolide resistance phenotypes.

  10. Novel plasmid conferring kanamycin and tetracycline resistance in the turkey-derived Campylobacter jejuni strain 11601MD.

    Science.gov (United States)

    Crespo, M D; Altermann, E; Olson, J; Miller, W G; Chandrashekhar, K; Kathariou, S

    2016-07-01

    In Campylobacter spp., resistance to the antimicrobials kanamycin and tetracycline is frequently associated with plasmid-borne genes. However, relatively few plasmids of Campylobacter jejuni have been fully characterized to date. A novel plasmid (p11601MD; 44,095nt) harboring tet(O) was identified in C. jejuni strain 11601MD, which was isolated from the jejunum of a turkey produced conventionally in North Carolina. Analysis of the p11601MD sequence revealed the presence of a high-GC content cassette with four genes that included tet(O) and a putative aminoglycoside transferase gene (aphA-3) highly similar to kanamycin resistance determinants. Several genes putatively involved in conjugative transfer were also identified on the plasmid. These findings will contribute to a better understanding of the distribution of potentially self-mobilizing plasmids harboring antibiotic resistance determinants in Campylobacter spp. from turkeys and other sources. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Effect of Ampicillin, Streptomycin, Penicillin and Tetracycline on Metal Resistant and Non-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Dagmar Chudobova

    2014-03-01

    Full Text Available There is an arising and concerning issue in the field of bacterial resistance, which is confirmed by the number of deaths associated with drug-resistant bacterial infections. The aim of this study was to compare the effects of antibiotics on Staphylococcus aureus non-resistant strain and strains resistant to cadmium or lead ions. Metal resistant strains were created by the gradual addition of 2 mM solution of metal ions (cadmium or lead to the S. aureus culture. An increasing antimicrobial effect of ampicillin, streptomycin, penicillin and tetracycline (0, 10, 25, 50, 75, 150, 225 and 300 µM on the resistant strains was observed using a method of growth curves. A significant growth inhibition (compared to control of cadmium resistant cells was observed in the presence of all the four different antibiotics. On the other hand, the addition of streptomycin and ampicillin did not inhibit the growth of lead resistant strain. Other antibiotics were still toxic to the bacterial cells. Significant differences in the morphology of cell walls were indicated by changes in the cell shape. Our data show that the presence of metal ions in the urban environment may contribute to the development of bacterial strain resistance to other substances including antibiotics, which would have an impact on public health.

  12. Chloramphenicol- and tetracycline-resistant uropathogenic Escherichia coli (UPEC) exhibit reduced virulence potential.

    Science.gov (United States)

    Starcic Erjavec, Marjanca; Rijavec, Matija; Krizan-Hergouth, Veronika; Fruth, Angelika; Zgur-Bertok, Darja

    2007-11-01

    It is well documented that uropathogenic Escherichia coli (UPEC) isolates resistant to nalidixic acid have reduced virulence potential. Our goal was to assess whether UPEC isolates resistant to chloramphenicol, tetracycline and streptomycin also exhibit reduced virulence potential. Among 110 human UPEC isolates, the prevalences of the virulence factors fimH, papC, papGII, papGIII, sfa/focDE, afa, hlyA, cnf1, usp, ibeA, fyuA, iroN, iucD, ireA, and K1 and K5 capsules as well as of pathotypes, phylogenetic groups, O antigens and a pathogenicity island (PAI) marker were compared between chloramphenicol-, tetracycline-, streptomycin- and, as a control, nalidixic acid-resistant and -susceptible strains. Our findings show that among human UPEC isolates, not only nalidixic acid-resistant but also chloramphenicol- and tetracycline-resistant isolates have reduced virulence potential compared with susceptible strains. To our knowledge, this is the first report of a statistically significant reduction in virulence traits among chloramphenicol- and tetracycline-resistant isolates.

  13. Effect of tetracycline dose and treatment mode on selection of resistant coliform bacteria in nursery pigs

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders

    2017-01-01

    This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig...... by the time that the pigs left the nursery unit. The counts and proportions of tetracyclineresistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated...... with tiamulin did not show significant changes in the numbers or proportions of tetracycline-resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin- and sulfonamide-resistant strains but not to selection for cefotaximeresistant strains...

  14. Changes in diversity of cultured bacteria resistant to erythromycin and tetracycline in swine manure during simulated composting and lagoon storage.

    Science.gov (United States)

    Wang, L; Gutek, A; Grewal, S; Michel, F C; Yu, Z

    2015-09-01

    This study investigated the impact of composting and lagoon storage on survival and change in diversity of tetracycline-resistant (Tc(r) ) and erythromycin-resistant (Em(r) ) bacteria and the resistance genes they carry in swine manure. Treatments were arranged as a 2 × 2 factorial design: composting vs lagoon storage and 0 vs 1% Surround WP Crop Protectant (a clay product) in three replicates. After 48 days of treatments, resistant bacteria were enumerated by selective plating and identified by 16S rRNA gene sequencing. The erm and the tet gene(s) carried by the resistant isolates were screened using class-specific PCR assays. The plate counts of Tc(r) and Em(r) bacteria decreased by 4-7 logs by composting, but only by 1-2 logs by the lagoon treatment. During the treatments, Acinetobacter gave way to Pseudomonas and Providencia as the largest resistant genera. The clay product had little effect on survival or diversity of resistant bacteria. Of six classes of erm and seven classes of tet genes tested, changes in prevalence were also noted. The results indicate that composting can dramatically shift Tc(r) and Em(r) bacterial populations, and composting can be an effective and practical approach to decrease dissemination of antibiotic resistance from swine farms to the environment. The presented research provided evidence that composting is much more effective than lagoon storage in dramatically decreasing culturable bacteria resistant to erythromycin and tetracycline in swine manure. Considerable diversity changes of resistant bacteria were also demonstrated during composting or lagoon storage. Overall, Acinetobacter was the major resistant genus in untreated swine manure, but pseudomonads and Providencia became the major resistant genera after the treatments. This is the first study that investigated diversity changes of cultured bacteria resistant to these two antibiotics during composting and lagoon storage of swine manure. New genes encoding resistance to

  15. Antibiotic resistance genes and residual antimicrobials in cattle feedlot surface soil

    Science.gov (United States)

    Antibiotic residues and resistant bacteria in cattle feedlot manure may impact antibiotic resistance in the environment. This study investigated common antimicrobials (tetracyclines and monensin) and associated resistance genes in cattle feedlot soils over time. Animal diets and other feedlot soil...

  16. Occurrence of integrons and resistance genes among sulphonamide-resistant Shigella spp. from Brazil

    DEFF Research Database (Denmark)

    Peirano, G.; Agersø, Yvonne; Aarestrup, Frank Møller

    2005-01-01

    of 2214 bp harbouring a gene cassette array conferring resistance to trimethoprim, streptothricin and spectinomycin/streptomycin. The genes coding for resistance to chloramphenicol (catA1), tetracycline [tet(A) and tet(B)] and ampicillin (bla(OXA) and bla(TEM)), were detected in resistant strains...

  17. Factors influencing the survival and leaching of tetracycline-resistant bacteria and Escherichia coli through structured agricultural fields

    DEFF Research Database (Denmark)

    Bech, Tina Bundgaard; Rosenbom, Annette E.; Kjær, Jeanne

    2014-01-01

    Intense use of antibiotics in agricultural production may lead to the contamination of surface and groundwater by antibiotic-resistant bacteria. In the present study, the survival and leaching of E. coli and tetracycline-resistant bacteria were monitored at two well-structured agricultural fields....... Non-spiked pig slurry was injected in accordance with agricultural practice in the area. In both fields, the concentration of E. coli and tetracycline-resistant bacteria in the injected part of the plough layer decreased to the detection limit within 46–49 days. At Silstrup the decay was initiated...... with a lag phase and a decimal reduction time of 16 days for E. coli and 18 days for tetracycline-resistant bacteria. At Estrup the decay was immediate and the decimal reduction time was 22 days for E .coli and 26 days for tetracycline-resistant bacteria. Despite the two fields being prone to rapid...

  18. Composite IS1-tetracycline resistance elements in aerobactin-encoding FIme plasmids from epidemic Salmonella wien.

    OpenAIRE

    Casalino, M.; Nicoletti, M; Junakovic, N; Maimone, F

    1988-01-01

    Class B tetracycline resistance determinants have been identified in two aerobactin-encoding FIme plasmids representative of those isolated from epidemic Salmonella wien. Genetic data, restriction enzyme analysis of recombinant and mutant plasmids, and Southern blot hybridizations indicate that in both plasmids the class B determinant so far found and described only on Tn10-like transposons is part of a different genetic element. This composite insertion sequence element is about 7 kilobases ...

  19. A previously functional tetracycline-regulated transactivator fails to target gene expression to the bone

    Directory of Open Access Journals (Sweden)

    Schmidt Eva

    2011-08-01

    Full Text Available Abstract Background The tetracycline-controlled transactivator system is a powerful tool to control gene expression in vitro and to generate consistent and conditional transgenic in vivo model organisms. It has been widely used to study gene function and to explore pathological mechanisms involved in human diseases. The system permits the regulation of the expression of a target gene, both temporally and quantitatively, by the application of tetracycline or its derivative, doxycycline. In addition, it offers the possibility to restrict gene expression in a spatial fashion by utilizing tissue-specific promoters to drive the transactivator. Findings In this study, we report our problems using a reverse tetracycline-regulated transactivator (rtTA in a transgenic mouse model system for the bone-specific expression of the Hutchinson-Gilford progeria syndrome mutation. Even though prior studies have been successful utilizing the same rtTA, expression analysis of the transactivator revealed insufficient activity for regulating the transgene expression in our system. The absence of transactivator could not be ascribed to differences in genetic background because mice in a mixed genetic background and in congenic mouse lines showed similar results. Conclusions The purpose of this study is to report our negative experience with previously functional transactivator mice, to raise caution in the use of tet-based transgenic mouse lines and to reinforce the need for controls to ensure the stable functionality of generated tetracycline-controlled transactivators over time.

  20. Effect of Tetracycline Dose and Treatment Mode on Selection of Resistant Coliform Bacteria in Nursery Pigs.

    Science.gov (United States)

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders; Herrero-Fresno, Ana; Larsen, Inge; Holm, Anders; Nielsen, Jens Peter; Christiansen, Lasse Engbo; Angen, Øystein; Ahmed, Shahana; Folkesson, Anders; Olsen, John Elmerdahl

    2017-06-15

    This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig herds were treated with oxytetracycline for Lawsonia intracellularis -induced diarrhea. Each group was randomly allocated to one of five treatment groups: oral flock treatment with a (i) high (20 mg/kg of body weight), (ii) medium (10 mg/kg), or (iii) low (5 mg/kg) dose, (iv) oral pen-wise (small-group) treatment (10 mg/kg), and (v) individual intramuscular injection treatment (10 mg/kg). All groups were treated once a day for 5 days. In all groups, treatment caused a rise in the numbers and proportions of tetracycline-resistant coliform bacteria right after treatment, followed by a significant drop by the time that the pigs left the nursery unit. The counts and proportions of tetracycline-resistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated with tiamulin did not show significant changes in the numbers or proportions of tetracycline-resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin- and sulfonamide-resistant strains but not to selection for cefotaxime-resistant strains. In conclusion, the difference in the dose of oxytetracycline and the way in which the drug was applied did not cause significantly different levels of selection of tetracycline-resistant coliform bacteria under the conditions tested. IMPORTANCE Antimicrobial resistance is a global threat to human health. Treatment of livestock with antimicrobials has a direct impact on this problem, and there is a need to improve the ways that we use antimicrobials in livestock

  1. Effect of Tetracycline Dose and Treatment Mode on Selection of Resistant Coliform Bacteria in Nursery Pigs

    Science.gov (United States)

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders; Herrero-Fresno, Ana; Larsen, Inge; Holm, Anders; Nielsen, Jens Peter; Christiansen, Lasse Engbo; Angen, Øystein; Ahmed, Shahana

    2017-01-01

    ABSTRACT This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig herds were treated with oxytetracycline for Lawsonia intracellularis-induced diarrhea. Each group was randomly allocated to one of five treatment groups: oral flock treatment with a (i) high (20 mg/kg of body weight), (ii) medium (10 mg/kg), or (iii) low (5 mg/kg) dose, (iv) oral pen-wise (small-group) treatment (10 mg/kg), and (v) individual intramuscular injection treatment (10 mg/kg). All groups were treated once a day for 5 days. In all groups, treatment caused a rise in the numbers and proportions of tetracycline-resistant coliform bacteria right after treatment, followed by a significant drop by the time that the pigs left the nursery unit. The counts and proportions of tetracycline-resistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated with tiamulin did not show significant changes in the numbers or proportions of tetracycline-resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin- and sulfonamide-resistant strains but not to selection for cefotaxime-resistant strains. In conclusion, the difference in the dose of oxytetracycline and the way in which the drug was applied did not cause significantly different levels of selection of tetracycline-resistant coliform bacteria under the conditions tested. IMPORTANCE Antimicrobial resistance is a global threat to human health. Treatment of livestock with antimicrobials has a direct impact on this problem, and there is a need to improve the ways that we use antimicrobials in

  2. Helicobacter pylori resistance rates for levofloxacin, tetracycline and rifabutin among Irish isolates at a reference centre.

    LENUS (Irish Health Repository)

    O'Connor, A

    2013-04-27

    INTRODUCTION: Helicobacter pylori eradication rates using conventional triple therapies are falling, making viable second-line and rescue regimens necessary. Levofloxacin, tetracycline and rifabutin are three efficacious antibiotics for rescue therapy. AIM: We aimed to assess the resistance rates for H. pylori against these antibiotics in an Irish cohort. METHODS: Gastric biopsies were collected from 85 patients infected with H. pylori (mean age 46 years) in the Adelaide and Meath Hospital, Dublin in 2008 and 2009. Susceptibility to antibiotics was tested using the Etest. Clinical information was obtained from endoscopy reports and chart review. RESULTS: 50.6 % of patients were females. Mean age was 47 years. Ten had prior attempts at eradication therapy with amoxicillin-clarithromycin-PPI, two had levofloxacin-based second-line therapy. 11.7 % [95 % CI (6.5-20.3 %)] (N = 10) had strains resistant to levofloxacin. There were no strains resistant to rifabutin or tetracycline. Levofloxacin resistance in the under 45 age group was 2.6 % (1\\/38) compared to 19.1 % (9\\/47) of above 45 age group (p = 0.02). DISCUSSION: The levofloxacin rates illustrated in this study are relatively low by European standards and in line with other studies from the United Kingdom and Germany, with younger patients having very low levels of resistance. Levofloxacin, tetracycline and rifabutin are all valid options for H. pylori eradication in Irish patients but the importance of compliance cannot be underestimated.

  3. Pharmacokinetic-Pharmacodynamic Model To Evaluate Intramuscular Tetracycline Treatment Protocols To Prevent Antimicrobial Resistance in Pigs

    DEFF Research Database (Denmark)

    Ahmad, Amais; Græsbøll, Kaare; Christiansen, Lasse Engbo

    2015-01-01

    High instances of antimicrobial resistance are linked to both routine and excessive antimicrobial use, but excessive or inappropriate use represents an unnecessary risk. The competitive growth advantages of resistant bacteria may be amplified by the strain dynamics; in particular, the extent...... protocol for intramuscular administration of tetracycline and the composition of bacterial strains in a pig affect the level of resistance in the intestine of a pig. Predictions were generated by a mathematical model of competitive growth of Escherichia coli strains in pigs under specified plasma...... the resistance levels. The number of competing strains had no apparent effect on the resistance level during treatment, but possession of fewer strains reduced the time to reach equilibrium after the end of treatment. To sum up, epidemiological parameters may have more profound influence on growth dynamics than...

  4. Quantitative proteome analysis of an antibiotic resistant Escherichia coli exposed to tetracycline reveals multiple affected metabolic and peptidoglycan processes.

    Science.gov (United States)

    Jones-Dias, Daniela; Carvalho, Ana Sofia; Moura, Inês Barata; Manageiro, Vera; Igrejas, Gilberto; Caniça, Manuela; Matthiesen, Rune

    2017-03-06

    Tetracyclines are among the most commonly used antibiotics administrated to farm animals for disease treatment and prevention, contributing to the worldwide increase in antibiotic resistance in animal and human pathogens. Although tetracycline mechanisms of resistance are well known, the role of metabolism in bacterial reaction to antibiotic stress is still an important assignment and could contribute to the understanding of tetracycline related stress response. In this study, spectral counts-based label free quantitative proteomics has been applied to study the response to tetracycline of the environmental-borne Escherichia coli EcAmb278 isolate soluble proteome. A total of 1484 proteins were identified by high resolution mass spectrometry at a false discovery rate threshold of 1%, of which 108 were uniquely identified under absence of tetracycline whereas 126 were uniquely identified in presence of tetracycline. These proteins revealed interesting difference in e.g. proteins involved in peptidoglycan-based cell wall proteins and energy metabolism. Upon treatment, 12 proteins were differentially regulated showing more than 2-fold change and pcoli provides novel insight into tetracycline related stress. The lack of new antibiotics to fight infections caused by multidrug resistant microorganisms has motivated the use of old antibiotics, and the search for new drug targets. The evolution of antibiotic resistance is complex, but it is known that agroecosystems play an important part in the selection of antibiotic resistance bacteria. Tetracyclines are still used as phytopharmaceutical agents in crops, selecting resistant bacteria and changing the ecology of farm soil. Little is known about the metabolic response of genetically resistant populations to antibiotic exposure. Indeed, to date there are no quantitative tetracycline resistance studies performed with the latest generation of high resolution mass spectrometers allowing high mass accuracy in both MS and MS

  5. Escherichia coli tetracycline efflux determinants in relation to tetracycline residues in chicken.

    Science.gov (United States)

    S N, Al-Bahry; B M, Al-Mashani; A S, Al-Ansari; A E, Elshafie; I Y, Mahmoud

    2013-09-01

    To screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS). Strains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tc(r)) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%). PCR analysis indicated that Tc(r)E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels. Tetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  6. Fate of antibiotic resistant bacteria and genes during wastewater chlorination: implication for antibiotic resistance control.

    Science.gov (United States)

    Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

    2015-01-01

    This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L). The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L). By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L). However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination.

  7. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters

    OpenAIRE

    Miller, Jennifer H.; Novak, John T.; Knocke, William R.; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) versus their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1- a Pseudomonas sp.) and thermophilic (Iso T10- a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts ...

  8. Survival and leaching of Tetracycline resistant bacteria and fecal indicators from manure in field scale experiments

    DEFF Research Database (Denmark)

    Bech, Tina; Amin, Mostofa; Lægdsmand, Mette

    The spreading of manure on agricultural land is an economic and practical solution for improving soil quality; however, animal manure frequently contains zoonotic pathogenic bacteria, such as certain Eschericia coli, Salmonella spp. and Campylobacter spp. The present experiment was conducted...... as a large multidisciplinary project. Pig manure with a natural content of Tetracycline resistant bacteria and fecal indicator organisms was followed in soil columns and a field scale experiment. In the field experiment pig manure was injected into agricultural soil. The distribution and survival of natural...... occurring indicator bacteria around a manure slurry slit in the soil was followed. During a period of two months, sections of soils with different distance to the manure string were assayed to obtain information on survival and spread of bacteriophage, faecal indicators (Enterococci, Bacterioides, E. coli...

  9. Escherichia coli resistant to tetracyclines and to other antibiotics in the faeces of U.K. chickens and pigs in 1980.

    OpenAIRE

    Smith, H. W.; Lovell, M. A.

    1981-01-01

    A survey conducted in 1980, 9 years after the banning of the use of tetracyclines as feed additives in the U.K., indicated that table chickens and pigs were still a large reservoir of tetracycline-resistant Escherichia coli; the incidence of transferable tetracycline resistance was greater in chicken E. coli strains (68%) than in pig E. coli strains (20%). Large amounts of sulphonamide-resistant and of furazolidone-resistant E. coli were found in the faeces of chickens; E. coli resistant to b...

  10. Stochastic simulations of the tetracycline operon

    Directory of Open Access Journals (Sweden)

    Kaznessis Yiannis N

    2011-01-01

    Full Text Available Abstract Background The tetracycline operon is a self-regulated system. It is found naturally in bacteria where it confers resistance to antibiotic tetracycline. Because of the performance of the molecular elements of the tetracycline operon, these elements are widely used as parts of synthetic gene networks where the protein production can be efficiently turned on and off in response to the presence or the absence of tetracycline. In this paper, we investigate the dynamics of the tetracycline operon. To this end, we develop a mathematical model guided by experimental findings. Our model consists of biochemical reactions that capture the biomolecular interactions of this intriguing system. Having in mind that small biological systems are subjects to stochasticity, we use a stochastic algorithm to simulate the tetracycline operon behavior. A sensitivity analysis of two critical parameters embodied this system is also performed providing a useful understanding of the function of this system. Results Simulations generate a timeline of biomolecular events that confer resistance to bacteria against tetracycline. We monitor the amounts of intracellular TetR2 and TetA proteins, the two important regulatory and resistance molecules, as a function of intrecellular tetracycline. We find that lack of one of the promoters of the tetracycline operon has no influence on the total behavior of this system inferring that this promoter is not essential for Escherichia coli. Sensitivity analysis with respect to the binding strength of tetracycline to repressor and of repressor to operators suggests that these two parameters play a predominant role in the behavior of the system. The results of the simulations agree well with experimental observations such as tight repression, fast gene expression, induction with tetracycline, and small intracellular TetR2 amounts. Conclusions Computer simulations of the tetracycline operon afford augmented insight into the

  11. Identification of Tet 39, a novel class of tetracycline resistance determinant in Acinetobacter spp. of environmental and clinical origin

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Guardabassi, L.

    2005-01-01

    A novel tetracycline resistance determinant named Tet 39 was found in unrelated Acinetobacter strains isolated from freshwater trout farms (n=4) and sewage (n=6) in Denmark, and from a clinical specimen in the Netherlands (n=1). The determinant was located on transferable plasmids and consisted o...

  12. A Simple Model of Tetracycline Antibiotic Resistance in the Aquatic Environment (with Application to the Poudre River

    Directory of Open Access Journals (Sweden)

    Sarah Sanchez

    2011-02-01

    Full Text Available Antibiotic resistance is a major concern, yet it is unclear what causes the relatively high densities of resistant bacteria in the anthropogenically impacted environment. There are various possible scenarios (hypotheses: (A Input of resistant bacteria from wastewater and agricultural sources is significant, but they do not grow in the environment; (B Input of resistant bacteria is negligible, but the resistant bacteria (exogenous or endogenous grow due to the selection pressure of the antibiotic; (C Exogenous bacteria transfer the resistance to the endogenous bacteria and those grow. This paper presents a simple mechanistic model of tetracycline resistance in the aquatic environment. It includes state variables for tetracyclines, susceptible and resistant bacteria, and particulate and dissolved organic matter in the water column and sediment bed. The antibiotic partitions between freely dissolved, dissolved organic matter (DOM-bound and solids-bound phases, and decays. Bacteria growth is limited by DOM, inhibited by the antibiotic (susceptible bacteria only and lower due to the metabolic cost of carrying the resistance (resistant bacteria only. Resistant bacteria can transfer resistance to the susceptible bacteria (conjugation and lose the resistance (segregation. The model is applied to the Poudre River and can reproduce the major observed (literature data patterns of antibiotic concentration and resistance. The model suggests observed densities of resistant bacteria in the sediment bed cannot be explained by input (scenario A, but require growth (scenarios B or C.

  13. Development of a miniaturised microarray-based assay for the rapid identification of antimicrobial resistance genes in Gram-negative bacteria

    DEFF Research Database (Denmark)

    Batchelor, Miranda; Hopkins, Katie L; Liebana, Ernesto

    2008-01-01

    We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and beta-lactams, including extended-spectrum ......We describe the development of a miniaturised microarray for the detection of antimicrobial resistance genes in Gram-negative bacteria. Included on the array are genes encoding resistance to aminoglycosides, trimethoprim, sulphonamides, tetracyclines and beta-lactams, including extended...

  14. Effects of tetracycline and zinc on selection of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 398 in pigs

    DEFF Research Database (Denmark)

    Moodley, Arshnee; Nielsen, Søren Saxmose; Guardabassi, Luca

    2011-01-01

    An in vivo experiment was conducted to evaluate the effects of tetracycline and zinc on pig colonization and transmission of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398. Eight piglets naturally colonized with MRSA ST398 and 8 MRSA-negative piglets of the same age...... and breed were assigned to three groups treated with tetracycline and zinc (Group 1), zinc (Group 2) or tetracycline alone (Group 3) and one non-treated group (Group 4), each containing two MRSA-positive and two MRSA-negative animals. Two additional non-treated control groups composed of only MRSA......-positive (Group 5) and MRSA-negative (Group 6) animals were used to check for stability of MRSA carriage status. Nasal swabs and environmental wipes were collected on Days 0, 7, 14, and 21, and the occurrence of MRSA in each sample was quantified by bacteriological counts on Brilliance™ MRSA agar. Significantly...

  15. Characterisation of penA and tetM resistance genes of Neisseria ...

    African Journals Online (AJOL)

    Objective. To investigate penA and tetM resistance gene variation of Neisseria gonorrhoeae in order to define gene types for epidemiological monitoring and resistance development. Design. Isolates of N. gonorrhoeae which were susceptible and resistant to penicillin and/or tetracycline were selected. Strains comprised ...

  16. Tetracycline improved the efficiency of other antimicrobials against Gram-negative multidrug-resistant bacteria.

    Science.gov (United States)

    Mawabo, Isabelle K; Noumedem, Jaurès A K; Kuiate, Jules R; Kuete, Victor

    2015-01-01

    Treatment of infectious diseases with antimicrobials constituted a great achievement in the history of medicine. Unfortunately, the emergence of resistant strains of bacteria to all classes of antimicrobials limited their efficacy. The present study was aimed at evaluating the effect of combinations of antibiotics on multi-drug resistant Gram-negative (MDRGN) bacteria. A liquid micro-broth dilution method was used to evaluate the antibacterial activity of 10 different classes of antimicrobials on 20 bacterial strains belonging to six different species. The antimicrobials were associated with phenylalanine β-naphthylamide (PAβN), an efflux pump inhibitor, and with other antimicrobials at their sub-inhibitory concentrations. The effectiveness of each combination was monitored using the minimal inhibitory concentration (MIC) and the fractional inhibitory concentration (FIC). Most of the antimicrobials tested showed low antibacterial activity with a MIC value of 128 mg/L on a majority of the bacterial strains, justifying their multidrug-resistant (MDR) profile. Synergistic effects were mostly observed (FIC≤0.5) when ampicillin (AMP), cloxacillin (CLX), erythromycin (ERY), chloramphenicol (CHL), kanamycin (KAN) and streptomycin (STR) were combined with tetracycline (TET) at the sub-inhibitory concentration of MIC/5 or MIC/10. The results of the present work suggest that the association of several antimicrobials with TET could improve the fight against MDRGN bacterial species. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  17. Chemosensitization of Trypanosoma congolense strains resistant to isometamidium chloride by tetracyclines and enrofloxacin.

    Directory of Open Access Journals (Sweden)

    Vincent Delespaux

    Full Text Available BACKGROUND: Because of the development of resistance in trypanosomes to trypanocidal drugs, the livelihood of millions of livestock keepers in sub-Saharan Africa is threatened now more than ever. The existing compounds have become virtually useless and pharmaceutical companies are not keen on investing in the development of new trypanocides. We may have found a breakthrough in the treatment of resistant trypanosomal infections, through the combination of the trypanocide isometamidium chloride (ISM with two affordable veterinary antibiotics. METHODOLOGY/PRINCIPAL FINDINGS: In a first experiment, groups of mice were inoculated with Trypanosoma congolense strains resistant to ISM and either left untreated or treated with (i tetracycline, (ii ISM or (iii the combination of the antibiotic and the trypanocide. Survival analysis showed that there was a significant effect of treatment and resistance to treatment on the survival time. The groups treated with ISM (with or without antibiotic survived significantly longer than the groups that were not treated with ISM (P<0.01. The group treated with the combination trypanocide/antibiotic survived significantly longer than the group treated with ISM (P<0.01. In a second experiment, groups of cattle were inoculated with the same resistant trypanosome strain and treated with (i ISM, (ii ISM associated with oxytetracycline or (iii ISM associated with enrofloxacine. All animals treated with ISM became parasitaemic. In the groups treated with ISM-oxytetracycline and ISM-enrofloxacine, 50% of the animals were cured. Animals from the groups treated with a combination trypanocide/antibiotic presented a significantly longer prepatent period than animals treated with ISM (p<0.001. The impact of the disease on the haematocrit was low in all ISM treated groups. Yet, it was lower in the groups treated with the combination trypanocide/antibiotic (p<0.01. CONCLUSIONS/SIGNIFICANCE: After optimization of the administration

  18. In vivo activity of fluconazole/tetracycline combinations in Galleria mellonella with resistant Candida albicans infection.

    Science.gov (United States)

    Gu, Wenrui; Yu, Qiong; Yu, Cuixiang; Sun, Shujuan

    2017-11-27

    The treatment of azoles-resistant Candida albicans infections continues to pose significant challenges. With limited options of licensed agents, the drug's combination turns out to be a practical way. In our previous studies, minocycline/fluconazole (MINO/FLC) and doxycycline/fluconazole (DOXY/FLC) combinations shown synergistic effect in vitro. It is necessary to explore appropriate dosage, potential toxicity and in vivo efficacy. The Galleria mellonella infection model was employed to study the in vivo efficacy of MINO/FLC and DOXY/FLC by survival analysis, quantification of C. albicans CFU/mL, and histological analysis. The survival rates of G. mellonella larvae infected with lethal doses of C. albicans increased significantly when drug combination was given compared to fluconazole treatment alone. The fungal burden reduced by almost 4-fold and histopathology study showed that fewer infected areas in larvae were observed and the destructive degree was slighter when larvae were exposed to combined drugs. The findings suggest that the combination of tetracycline and fluconazole has antifungal activity against azoles-resistant Candida albicans in vivo. This is in agreement with several previous in vitro studies and provides preliminary in vivo evidence that such a combination might be useful therapeutically. Copyright © 2017. Published by Elsevier Ltd.

  19. Technical advance: transcriptional activator TGV mediates dexamethasone-inducible and tetracycline-inactivatable gene expression

    Science.gov (United States)

    Bohner; Lenk; Rieping; Herold; Gatz

    1999-07-01

    A chemically regulated gene expression system that can be switched on with dexamethasone and switched off with tetracycline was constructed. It is based on a transcriptional activator (TGV) that consists of the Tn10 encoded Tet repressor, the rat glucocorticoid receptor hormone binding domain and the transcriptional activation domain of Herpes simplex virion protein VP16. When stably expressed in transgenic tobacco plants, it mediates dexamethasone-inducible transcription from a synthetic promoter (PTop10) consisting of seven tet operators upstream of a TATA-box. Tetracycline interferes with induction by negatively regulating the DNA-binding activity of the TetR moiety of TGV. The boundaries of the expression window of the TGV-driven PTop10 reach from undetectable levels of the reporter enzyme beta-glucuronidase in the absence of dexa- methasone to induced levels reaching 15-20% of the Cauliflower Mosaic Virus 35S promoter (PCaMV35S). By modifying the sequence of PTop10, we generated a new target promoter (PTax) that is stably expressed over several generations and that can be activated to levels comparable to PCaMV35S, while yielding only slightly elevated background activities.

  20. Behavioral and socioeconomic risk factors associated with probable resistance to ceftriaxone and resistance to penicillin and tetracycline in Neisseria gonorrhoeae in Shanghai.

    Directory of Open Access Journals (Sweden)

    Molly A Trecker

    Full Text Available Globally, incidence of Neisseria gonorrhoeae infection is once again the highest of the bacterial sexually transmitted infections. The bacterium can produce serious complications in those infected, and emerging resistance to third generation cephalosporins could usher in an era of potentially untreatable gonorrhea. This research aimed to identify risk factors for antibiotic resistant gonorrhea infection among clients at a Shanghai sexually transmitted infection clinic over two time periods, 2004-2005 and 2008-2011. Demographic and risk factor behavior data, and biological samples for antimicrobial resistance analysis, were collected. Statistical models were built to identify risk factors associated with probable resistance to ceftriaxone and resistance to penicillin and tetracycline. High levels of ciprofloxacin resistance (98% in our sample precluded examining its risk factors; all isolates were susceptible to spectinomycin. Overall (P<0.001, chromosomal (P<0.001, and plasmid-mediated (P = 0.01 penicillin resistance decreased from the first to second period of the study. For tetracycline, chromosomal resistance decreased (P = 0.01 and plasmid-mediated resistance increased (P<0.001 between the first and second periods of study. In multi-level multivariable regression models, male gender (P = 0.03 and older age (P = 0.01 were associated with increased minimum inhibitory concentrations to ceftriaxone. Male gender (P = 0.03 and alcohol use (P = 0.02 were associated with increased odds of overall tetracycline resistance. Male gender was associated with increased odds of chromosomally-mediated tetracycline resistance (P = 0.04, and alcohol use was associated with increased odds of plasmid-mediated tetracycline resistance (P = 0.02. Additionally, individuals in middle-salary categories were found to have lower odds of plasmid-mediated resistance to tetracycline compared with those in the lowest salary category (P≤0

  1. Fate of antibiotic resistance genes and metal resistance genes during thermophilic aerobic digestion of sewage sludge.

    Science.gov (United States)

    Jang, Hyun Min; Lee, Jangwoo; Kim, Young Beom; Jeon, Jong Hun; Shin, Jingyeong; Park, Mee-Rye; Kim, Young Mo

    2018-02-01

    This study examines the fate of twenty-three representative antibiotic resistance genes (ARGs) encoding tetracyclines, sulfonamides, quinolones, β-lactam antibiotics, macrolides, florfenicol and multidrug resistance during thermophilic aerobic digestion (TAD) of sewage sludge. The bacterial community, class 1 integrons (intI1) and four metal resistance genes (MRGs) were also quantified to determine the key drivers of changes in ARGs during TAD. At the end of digestion, significant decreases in the quantities of ARGs, MRGs and intI1 as well as 16S rRNA genes were observed. Partial redundancy analysis (RDA) showed that shifts in temperature were the key factors affecting a decrease in ARGs. Shifts in temperature led to decreased amounts of ARGs by reducing resistome and bacterial diversity, rather than by lowering horizontal transfer potential via intI1 or co-resistance via MRGs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. PROFILES OF GENE EXPRESSION ASSOCIATED WITH TETRACYCLINE OVER EXPRESSION OF HSP70 IN MCF-7 BREAST CANCER CELLS

    Science.gov (United States)

    Profiles of gene expression associated with tetracycline over expression of HSP70 in MCF-7 breast cancer cells. Heat shock proteins (HSPs) protect cells from damage through their function as molecular chaperones. Some cancers reveal high levels of HSP70 expression in asso...

  3. Sequence-based characterization of Tn5801-like genomic islands in tetracycline-resistant Staphylococcus pseudintermedius and other Gram-positive bacteria from humans and animals

    Directory of Open Access Journals (Sweden)

    Lisbeth Elvira De Vries

    2016-04-01

    Full Text Available Antibiotic resistance in pathogens is often associated with mobile genetic elements, such as genomic islands (GI including integrative and conjugative elements (ICEs. These can transfer resistance genes within and between bacteria from humans and/or animals. The aim of this study was to investigate whether Tn5801-like GIs carrying the tetracycline resistance gene, tet(M, are common in Staphylococcus pseudintermedius from pets, and to do an overall sequences-based characterization of Tn5801-like GIs detected in Gram-positive bacteria from humans and animals. A total of 27 tetracycline-resistant S. pseudintermedius isolates from Danish pets (1998-2005 were screened for tet(M by PCR. Selected isolates (13 were screened for GI- or ICE-specific genes (intTn5801 or xisTn916 and their tet(M gene was sequenced (Sanger-method. Long-range PCR mappings and whole-genome-sequencing (Illumina were performed for selected S. pseudintermedius-isolates (7 and 3 isolates, respectively as well as for human Staphylococcus aureus isolates (7 and 1 isolates, respectively and one porcine Enterococcus faecium isolate known to carry Tn5801-like GIs. All 27 S. pseudintermedius were positive for tet(M. Out of 13 selected isolates, 7 contained Tn5801-like GIs and 6 contained Tn916-like ICEs. Two different Tn5801-like GI types were detected among S. pseudintermedius (Tn5801 and GI6287 - both showed high similarity compared to GenBank sequences from human pathogens. Two distinct Tn5801-like GI types were detected among the porcine E. faecium and human S. aureus isolates (Tn6014 and GI6288. Tn5801-like GIs were detected in GenBank-sequences from Gram-positive bacteria of human, animal or food origin worldwide. Known Tn5801-like GIs were divided into 7 types. The results showed that Tn5801-like GIs appear to be relatively common in tetracycline-resistant S. pseudintermedius in Denmark. Almost identical Tn5801-like GIs were identified in different Gram-positive species of pet

  4. Insight into synergetic mechanisms of tetracycline and the selective serotonin reuptake inhibitor, sertraline, in a tetracycline-resistant strain of Escherichia coli

    DEFF Research Database (Denmark)

    Li, Lili; Kromann, Sofie; Olsen, John Elmerdahl

    2017-01-01

    '1). RNA data suggest changes in respiration that is likely to decrease intracellular pH and thereby the proton-motive force, which provides the energy for the tetracycline efflux pump. Furthermore, sertraline and tetracycline may induce a change from oxidation to fermentation in the E.coli, which...

  5. Graphene oxide in the water environment could affect tetracycline-antibiotic resistance.

    Science.gov (United States)

    Guo, Mei-Ting; Zhang, Guo-Sheng

    2017-09-01

    In recent years, the influence of new materials like nanoparticles in the water environment on biological substances has been widely studied. Antibiotic resistance genes (ARGs) represent a new type of pollutant in the environment. Graphene oxide (GO), as a nano material, because of its unique structure, may have an impact on antibiotic resistance bacteria (ARB) and ARGs; however the research in this area is rarely reported. Therefore, this study mainly investigated the effects of GO on bacterial antibiotic resistance. The results showed that GO had a limited effect on ARB inactivation. A high concentration of GO (>10 mg/L) can damage resistant plasmids to reduce bacterial resistance to antibiotics, but low concentrations of GO (antibiotic resistance needs further investigation. Copyright © 2017. Published by Elsevier Ltd.

  6. Resistência do Plasmodium falciparum ao fansidar, quinina e tetraciclina Resistance of Plasmodium falciparum to fansidar, quinine and tetracycline

    Directory of Open Access Journals (Sweden)

    Fernando Hélio Alencar

    1982-10-01

    Full Text Available Descreve-se pela primeira vez uma cêpa amazônica de Plasmodium falciparum resistente ao Fansidar (pirimetamina mais sulfadoxina e quinino mais tetraciclina simultaneamente. O paciente, com 13 anos de idade, residia há cinco anos em Ariquemes, Estado de Rondônia, na Amazônia brasileira. A infecção foi curada com dose elevada de cloroquina administrada em dose única intravenosa (IV. É evidenciado o alto valor da cloroquina na cura da malária falciparum resistente, quando administrada em doses maiores que as usadas nos esquemas convencionais de tratamento.For the first time an Amazonian strain of Plasmodium falciparum resistant to FansidarR (pyrimethamine + sulfadoxine and quinine + tetracycline, taken sequentially is described. This case involves a female patient 13 years old, living for five years in Ariquemes County, State of Rondônia, in the Brazilian Amazon. The infection was cured with a single high dose of chloroquine administered intravenously. The authors point out the high valor of chloroquine in treating falciparum-resistant malaria, especially when given in higher doses than the standard one used for malaria therapy.

  7. Tigecycline resistance in clinical isolates of Enterococcus faecium is mediated by an upregulation of plasmid-encoded tetracycline determinants tet(L) and tet(M).

    Science.gov (United States)

    Fiedler, S; Bender, J K; Klare, I; Halbedel, S; Grohmann, E; Szewzyk, U; Werner, G

    2016-04-01

    Tigecycline represents one of the last-line therapeutics to combat multidrug-resistant bacterial pathogens, including VRE and MRSA. The German National Reference Centre for Staphylococci and Enterococci has received 73 tigecycline-resistant Enterococcus faecium and Enterococcus faecalis isolates in recent years. The precise mechanism of how enterococci become resistant to tigecycline remains undetermined. This study documents an analysis of the role of efflux pumps in tigecycline resistance in clinical isolates of Enterococcus spp. Various tigecycline MICs were found for the different isolates analysed. Tigecycline-resistant strains were analysed with respect to genome and transcriptome differences by means of WGS and RT-qPCR. Genes of interest were cloned and expressed in Listeria monocytogenes for verification of their functionality. Detailed comparative whole-genome analyses of three isogenic strains, showing different levels of tigecycline resistance, revealed the major facilitator superfamily (MFS) efflux pump TetL and the ribosomal protection protein TetM as possible drug resistance proteins. Subsequent RT-qPCR confirmed up-regulation of the respective genes. A correlation of gene copy number and level of MIC was inferred from further qPCR analyses. Expression of both tet(L) and tet(M) in L. monocytogenes unequivocally demonstrated the potential to increase tigecycline MICs upon acquisition of either locus. Our results indicate that increased expression of two tetracycline resistance determinants, a tet(L)-encoded MFS pump and a tet(M)-encoded ribosomal protection protein, is capable of conferring tigecycline resistance in enterococcal clinical isolates. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Tetracycline-inducible system for regulation of skeletal muscle-specific gene expression in transgenic mice

    Science.gov (United States)

    Grill, Mischala A.; Bales, Mark A.; Fought, Amber N.; Rosburg, Kristopher C.; Munger, Stephanie J.; Antin, Parker B.

    2003-01-01

    Tightly regulated control of over-expression is often necessary to study one aspect or time point of gene function and, in transgenesis, may help to avoid lethal effects and complications caused by ubiquitous over-expression. We have utilized the benefits of an optimized tet-on system and a modified muscle creatine kinase (MCK) promoter to generate a skeletal muscle-specific, doxycycline (Dox) controlled over-expression system in transgenic mice. A DNA construct was generated in which the codon optimized reverse tetracycline transactivator (rtTA) was placed under control of a skeletal muscle-specific version of the mouse MCK promoter. Transgenic mice containing this construct expressed rtTA almost exclusively in skeletal muscles. These mice were crossed to a second transgenic line containing a bi-directional promoter centered on a tet responder element driving both a luciferase reporter gene and a tagged gene of interest; in this case the calpain inhibitor calpastatin. Compound hemizygous mice showed high level, Dox dependent muscle-specific luciferase activity often exceeding 10,000-fold over non-muscle tissues of the same mouse. Western and immunocytochemical analysis demonstrated similar Dox dependent muscle-specific induction of the tagged calpastatin protein. These findings demonstrate the effectiveness and flexibility of the tet-on system to provide a tightly regulated over-expression system in adult skeletal muscle. The MCKrtTA transgenic lines can be combined with other transgenic responder lines for skeletal muscle-specific over-expression of any target gene of interest.

  9. The effect of production type and antimicrobial usage on the occurrence of tetracycline resistant E. coli in danish slaughter pig farms

    DEFF Research Database (Denmark)

    Struve, Tina; Vigre, Håkan; Wingstrand, Anne

    systems. At nine different slaughterhouses 1500 ceacum samples were collected from slaughter pigs originating from 226 farms. One thousand samples were analyzed and one E. coli isolate per sample was susceptibility tested to Tetracycline. Data on management practice and health status at farm level...... was collected through telephone interviews. Data on antimicrobial consumption at farm level was collected from the Danish surveillance program VetStat. In total, 99 farms used Tetracycline and participated in the interview and from these farms, 411 isolates were available. We assumed that production type...... (organic, free range and conventional farms) was a risk factor for occurrence of antimicrobial resistance and Tetracycline usage was regarded as an intervening factor between production type and occurrence of antimicrobial resistance. Therefore, the effect of production type and Tetracycline usage...

  10. Occurrence of antibiotic resistance and characterization of resistant genes and integrons in Enterobacteriaceae isolated from integrated fish farms south China

    Science.gov (United States)

    Su, Hao-Chang; Ying, Guang-Guo; Tao, Ran; Zhang, Rui-Quan; Fogarty, Lisa R.; Kolpin, Dana W.

    2011-01-01

    Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase chain reaction (PCR) assays were carried out to test antibiotic susceptibility and resistance genes, respectively. Relatively high antibiotic resistance frequencies were found, especially for ampicillin (80%), tetracycline (52%), and trimethoprim (50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more antibiotics tested. Multiple antibiotic resistance (MAR) was found highest in animal manures with a MAR index of 0.56. Tetracycline resistance genes (tet(A), tet(C)) and sulfonamide resistance genes (sul2) were detected in more than 50% of the isolates. The intI1 gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes, aadA5, aadA22, dfr2, and dfrA17, were detected. To our knowledge, this is the first report for molecular characterization of antibiotic resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array dfrA17-aadA5 has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant antibiotic resistant genes and gene cassettes. Integrons may play a key role in multiple antibiotic resistances posing potential health risks to the general public and aquaculture.

  11. Effect of tetracycline dose and treatment-mode on selection of resistant coliform bacteria in nursery pigs

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Damborg, Peter; Mellerup, Anders

    2017-01-01

    with oxytetracycline against Lawsonia intracellularis induced diarrhea in five pig herds. Each group was randomly allocated to one of five treatment groups: oral flock treatment with (i) high (20 mg/kg), (ii) medium (10 mg/kg) and (iii) low (5 mg/kg) dosage, (iv) oral-pen-wise (small group) treatment (10 mg...... and the way the drug was applied did not cause significantly different selection of tetracycline resistant coliform bacteria, under the conditions tested.IMPORTANCE Antimicrobial resistance is a global treat to human health. Treatment of livestock with antimicrobials has a direct impact on this problem...... the environment with treated animals and take up resistant bacteria from the environment....

  12. Cell-to-cell diversity in protein levels of a gene driven by a tetracycline inducible promoter

    Directory of Open Access Journals (Sweden)

    Yli-Harja Olli

    2011-05-01

    Full Text Available Abstract Background Gene expression in Escherichia coli is regulated by several mechanisms. We measured in single cells the expression level of a single copy gene coding for green fluorescent protein (GFP, integrated into the genome and driven by a tetracycline inducible promoter, for varying induction strengths. Also, we measured the transcriptional activity of a tetracycline inducible promoter controlling the transcription of a RNA with 96 binding sites for MS2-GFP. Results The distribution of GFP levels in single cells is found to change significantly as induction reaches high levels, causing the Fano factor of the cells' protein levels to increase with mean level, beyond what would be expected from a Poisson-like process of RNA transcription. In agreement, the Fano factor of the cells' number of RNA molecules target for MS2-GFP follows a similar trend. The results provide evidence that the dynamics of the promoter complex formation, namely, the variability in its duration from one transcription event to the next, explains the change in the distribution of expression levels in the cell population with induction strength. Conclusions The results suggest that the open complex formation of the tetracycline inducible promoter, in the regime of strong induction, affects significantly the dynamics of RNA production due to the variability of its duration from one event to the next.

  13. Two Different Tetracycline Resistance Mechanisms, Plasmid-Carried tet(L) and Chromosomally Located Transposon-Associated tet(M), Coexist in Lactobacillus sakei Rits 9

    NARCIS (Netherlands)

    Ammor, M.S.; Gueimonde, M.; Danielsen, M.; Zagorec, M.; Hoek, van A.H.A.M.; Reyes-Gavilán, de los C.G.; Mayo, B.; Margolles, A.

    2008-01-01

    Lactobacillus sakei is extensively used as functional starter culture in fermented meat products. One of the safety criteria of a starter culture is the absence of potentially transferable antibiotic resistance determinants. However, tetracycline-resistant L. sakei strains have already been

  14. The prevalence and epidemiology of plasmid-mediated penicillin and tetracycline resistance among Neisseria gonorrhoeae isolates in Guangzhou, China, 2002-2012.

    Science.gov (United States)

    Zheng, Heping; Wu, Xingzhong; Huang, Jinmei; Qin, Xiaolin; Xue, Yaohua; Zeng, Weiying; Lan, Yinyuan; Ou, Jiangli; Tang, Sanmei; Fang, Mingheng

    2015-10-09

    Gonococcal antimicrobial resistance is a global problem. Different resistance plasmids have emerged and spread among the isolates of Neisseria gonorrhoeae worldwide and in China. We conducted this study to monitor the plasmid-mediated penicillin and tetracycline resistance among N. gonorrhoeae isolates in Guangzhou from 2002 to 2012. Consecutive isolates of N. gonorrhoeae were collected from outpatients with gonorrhea attending the STD clinic in Guangdong Provincial Centre for Skin Diseases and STIs Control and Prevention. Penicillinase-producing N. gonorrhoeae (PPNG) isolates were analyzed by the paper acidometric method. Plasmid-mediated resistance to tetracycline in N. gonorrhoeae (TRNG) isolates was screened by the agar plate dilution method. Plasmid types were determined for TRNG and PPNG isolates using polymerase chain reaction (PCR). Minimum inhibitory concentrations (MICs) to penicillin and tetracycline were detected by the agar plate dilution. Of 1378 consecutive N. gonorrhoeae isolates, 429 PPNG and 639 TRNG isolates were identified. The prevalence of PPNG, TRNG, and PPNG/TRNG increased from 18.3 to 47.1 % (χ (2) = 31.57, p penicillin G and tetracycline persisted at high levels and the MIC90s were 32-fold higher than the resistant cutoff point over 11 years. The prevalence rates of penicillin- and tetracycline-resistant N. gonorrhoeae varied from 90.9 to 91.1 % and from 88.3 to 89.3 % during 2002 to 2012, respectively. Resistance to penicillin and tetracycline among N. gonorrhoeae isolates remained at high levels in Guangzhou. The Asian type PPNG continued to spread and Dutch type TRNG was still the dominant strain. The African type PPNG has emerged and is spreading rapidly.

  15. Antimicrobial resistance of Neisseria gonorrhoeae isolates in south-west Germany, 2004 to 2015: increasing minimal inhibitory concentrations of tetracycline but no resistance to third-generation cephalosporins.

    Science.gov (United States)

    Regnath, Thomas; Mertes, Thomas; Ignatius, Ralf

    2016-09-08

    Increasing antimicrobial resistance of Neisseria gonorrhoeae, particularly to third-generation cephalosporins, has been reported in many countries. We examined the susceptibility (determined by Etest and evaluated using the breakpoints of the European Committee on Antimicrobial Susceptibility Testing) of 434 N. gonorrhoeae isolates collected from 107 female and 327 male patients in Stuttgart, south-west Germany, between 2004 and 2015. During the study period, high proportions of isolates were resistant to ciprofloxacin (70.3%), tetracycline (48.4%; increasing from 27.5% in 2004/2005 to 57.7% in 2014/2015; p = 0.0002) and penicillin (25.6%). The proportion of isolates resistant to azithromycin was low (5.5%) but tended to increase (p = 0.08). No resistance and stable minimum inhibitory concentrations were found for cefixime, ceftriaxone, and spectinomycin. High-level resistance was found for ciprofloxacin (39.6%) and tetracycline (20.0%) but not for azithromycin; 16.3% of the isolates produced betalactamase. Thus, cephalosporins can still be used for the treatment of gonorrhoea in the study area. To avoid further increasing resistance to azithromycin, its usage should be limited to patients allergic to cephalosporins, or (in combination with cephalosporins) to patients for whom no susceptibility testing could be performed or those co-infected with chlamydiae. This article is copyright of The Authors, 2016.

  16. PCR detection of oxytetracycline resistance genes from diverse habitats in total community DNA and in streptomycete isolates.

    NARCIS (Netherlands)

    Nikolakopoulou, T.L.; Egan, S.; Overbeek, van L.S.; Guillaume, G.; Heuer, H.; Wellington, E.M.H.; Elsas, van J.D.; Collard, J.M.; Smalla, K.; Karagouni, A.D.

    2005-01-01

    A range of European habitats was screened by PCR for detection of the oxytetracycline resistance genes otr(A) and otr(B), found in the oxytetracycline-producing strain Streptomyces rimosus. Primers were developed to detect these otr genes in tetracycline-resistant (TcR) streptomycete isolates from

  17. Characterization of tetracycline and methicillin resistant Staphylococcus aureus strains in a Spanish hospital: is livestock-contact a risk factor in infections caused by MRSA CC398?

    Science.gov (United States)

    Benito, Daniel; Lozano, Carmen; Rezusta, Antonio; Ferrer, Isabel; Vasquez, Maria Alejandra; Ceballos, Sara; Zarazaga, Myriam; Revillo, Maria José; Torres, Carmen

    2014-11-01

    Tetracycline-resistance (Tet(R)) has been postulated as a marker of the livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) lineage CC398. to determine the spa-types and assigned MLST clonal complexes (CCs) among all 98 MRSA-Tet(R) strains recovered during 2011-2012 (from different patients) in a Spanish Hospital, analyzing the possible correlation with livestock-contact of the patients. All 98 strains were assigned to 9 CCs: CC398 (60.2%), CC1 (19.4%), CC5 (12.2%), and other CCs (8.2%). The 98 patients were classified into three groups: (A) contact with livestock-animals (n=25); (B) no-contact with livestock-animals (n=42); (C) no information about animal contact (n=31). A significant higher percentage of CC398 strains was obtained in group A (76%) than in group B (50%) (pMRSA-Tet(R)-CC398 strains presented a multi-resistance phenotype, including erythromycin, clindamycin, and ciprofloxacin, and the most prevalent detected genes were tet(M) and erm(C). Three strains presented the phenotype macrolide-susceptibility/lincosamide-resistance and contained the vga(A) gene. MRSA-CC1 strains showed higher percentages of erythromycin/clindamycin resistance (95%/89%) than MRSA-CC398 strains (58%/63%), and this resistance was usually mediated by erm(C) gene. Most of MRSA-CC5 strains showed resistance to ciprofloxacin, tobramycin/kanamycin and erythromycin. None of the strains presented the genes lukF/lukS-PV, tsst-1, eta, etb or etd. All MRSA-CC398 strains lacked the genes of the immune-evasion-cluster, but MRSA-CC1 strains carried these genes (type E). In conclusion, although MRSA CC398 is detected in a significant higher proportion in patients with livestock-contact; its detection in people without this type of contact also indicates its capacity for human-to-human transmission. Copyright © 2014 Elsevier GmbH. All rights reserved.

  18. Antimicrobial resistance genes in Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida isolated from Australian pigs.

    Science.gov (United States)

    Dayao, Dae; Gibson, J S; Blackall, P J; Turni, C

    2016-07-01

    To identify genes associated with the observed antimicrobial resistance in Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida isolated from Australian pigs. Isolates with known phenotypic resistance to β-lactams, macrolides and tetracycline were screened for the presence of antimicrobial resistance genes. A total of 68 A. pleuropneumoniae, 62 H. parasuis and 20 P. multocida isolates exhibiting phenotypic antimicrobial resistance (A. pleuropneumoniae and P. multocida) or elevated minimal inhibitory concentrations (MICs) (H. parasuis) to any of the following antimicrobial agents - ampicillin, erythromycin, penicillin, tetracycline, tilmicosin and tulathromycin - were screened for a total of 19 associated antimicrobial resistance genes (ARGs) by PCR. The gene bla ROB-1 was found in all ampicillin- and penicillin-resistant isolates, but none harboured the bla TEM-1 gene. The tetB gene was found in 76% (74/97) of tetracycline-resistant isolates, 49/53 A. pleuropneumoniae, 17/30 H. parasuis and 8/14 P. multocida. One A. pleuropneumoniae isolate harboured the tetH gene, but none of the 97 isolates had tetA, tetC, tetD, tetE, tetL, tetM or tetO. A total of 92 isolates were screened for the presence of macrolide resistance genes. None was found to have ermA, ermB, ermC, erm42, mphE, mefA, msrA or msrE. The current study has provided a genetic explanation for the resistance or elevated MIC of the majority of isolates of Australian porcine respiratory pathogens to ampicillin, penicillin and tetracycline. However, the macrolide resistance observed by phenotypic testing remains genetically unexplained and further studies are required. © 2016 Australian Veterinary Association.

  19. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters.

    Science.gov (United States)

    Miller, Jennifer H; Novak, John T; Knocke, William R; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1-a Pseudomonas sp.) and thermophilic (Iso T10-a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457-0.829, P horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and/or horizontal gene transfer between raw sludge bacteria and the digester microbial community.

  20. Antibiotic resistance and virulence genes in coliform water isolates.

    Science.gov (United States)

    Stange, C; Sidhu, J P S; Tiehm, A; Toze, S

    2016-11-01

    Widespread fecal pollution of surface water may present a major health risk and a significant pathway for dissemination of antibiotic resistance bacteria. The River Rhine is one of the longest and most important rivers in Europe and an important raw water source for drinking water production. A total of 100 coliform isolates obtained from River Rhine (Germany) were examined for their susceptibility to seven antimicrobial agents. Resistances against amoxicillin, trimethoprim/sulfamethoxazole and tetracycline were detected in 48%, 11% and 9% of isolates respectively. The antibiotic resistance could be traced back to the resistance genes blaTEM, blaSHV, ampC, sul1, sul2, dfrA1, tet(A) and tet(B). Whereby, the ampC gene represents a special case, because its presence is not inevitably linked to a phenotypic antibiotic resistance. Multiple antibiotics resistance was often accompanied by the occurrence of class 1 or 2 integrons. E. coli isolates belonging to phylogenetic groups A and B1 (commensal) were more predominant (57%) compared to B2 and D groups (43%) which are known to carry virulent genes. Additionally, six E. coli virulence genes were also detected. However, the prevalence of virulence genes in the E. coli isolates was low (not exceeding 4.3% per gene) and no diarrheagenic E. coli pathotypes were detected. This study demonstrates that surface water is an important reservoir of ARGs for a number of antibiotic classes such as sulfonamide, trimethoprim, beta-lactam-antibiotics and tetracycline. The occurrence of antibiotic resistance in coliform bacteria isolated from River Rhine provides evidence for the need to develop management strategies to limit the spread of antibiotic resistant bacteria in aquatic environment. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. Prevalence of tetracycline resistance and genotypic analysis of populations of Escherichia coli from animals, carcasses and cuts processed at a pig slaughterhouse

    DEFF Research Database (Denmark)

    Shuyu, Wu; Dalsgaard, Anders; Vieira, Antonio R

    2009-01-01

    A Danish pig slaughterhouse was visited in this study to investigate the impact of carcass processing on prevalence of tetracycline-resistant Escherichia coli, and to identify the origins of carcass contaminations with E. coli by assessing genetic diversity of E. coli populations on carcasses. A ...

  2. [Integrons and antimicrobial resistance gene cassettes in Shigella flexneri strains ].

    Science.gov (United States)

    Muñoz, Jeannette; Bello, Helia; Domínguez, Mariana; Mella, Sergio; Zemelman, Raúl; González, Gerardo

    2003-07-01

    The resistance of Shigella flexneri to antimicrobial agents can be associated to the presence of integrons that may contain and express antimicrobial resistance gene cassettes. To study antimicrobial resistance and the presence of integrons and antimicrobial gene cassettes in Shigella flexneri strains. In vitro susceptibility to 27 antimicrobials was studied in twenty four Shigella flexneri strains isolated from stools. The presence of integrons class 1, 2 and 3 and antimicrobial resistance gene cassettes was investigated by polymerase chain reaction (PCR) using specific primers for each gene. Most strains were resistant to one of the following antimicrobials: ampicillin, sulphonamide, trimethoprim, tetracycline, streptomycin, sulfamethoxazole-trimethoprim or chloramphenicol. Twenty nine percent were simultaneously resistant to all these antimicrobials. Integrons class 1 and 2 were found in 19 strains (79%). Class 3 integrons were not found. Gene cassettes dfrA1 and ant(3")I were associated to integrons class 2 in most strains (15/20, 75%). Genes cat, tetB and blarTEM were detected in 18/24 (75%), 7/24 (29%) and 4/24 (17%) of the strains, respectively and were not associated to any of the studied integrons. Genes that codify enzymes AAC(6')Ib and APH(3')VI were not detected in any strain. The high frequency of integrons found in the studied strains, could partly explain the increasing antimicrobial resistance of Shigella flexneri strains, isolated in Chile.

  3. Detection and coexistence of six categories of resistance genes in Escherichia coli strains from chickens in Anhui Province, China

    Directory of Open Access Journals (Sweden)

    Lin Li

    2015-12-01

    Full Text Available The aim of this study was to characterise the prevalence of class 1 integrons and gene cassettes, tetracycline-resistance genes, phenicol-resistance genes, 16S rRNA methylase genes, extended-spectrum β-lactamase genes and plasmid-mediated fluoroquinolone resistance determinants in 184 Escherichia coli isolates from chickens in Anhui Province, China. Susceptibility to 15 antimicrobials was determined using broth micro-dilution. Polymerase chain reaction and DNA sequencing were used to characterise the molecular basis of the antibiotic resistance. High rates of antimicrobial resistance were observed; 131 out of the 184 (72.3% isolates were resistant to at least six antimicrobial agents. The prevalences of class 1 integrons, tetracycline-resistance genes, phenicol-resistance genes, 16S rRNA methylase genes, extended-spectrum β-lactamase genes and plasmid-mediated fluoroquinolone resistance determinants were 49.5, 17.4, 15.8, 0.5, 57.6 and 46.2%, respectively. In 82 isolates, 48 different kinds of coexistence of the different genes were identified. Statistical (χ2 analysis showed that the resistance to amoxicillin, doxycycline, florfenicol, ofloxacin and gentamicin had significant differences (P<0.01 or 0.01resistance genes, which showed a certain correlation between antimicrobial resistance and the presence of resistance genes.

  4. Pediatric fecal microbiota harbor diverse and novel antibiotic resistance genes.

    Directory of Open Access Journals (Sweden)

    Aimée M Moore

    Full Text Available Emerging antibiotic resistance threatens human health. Gut microbes are an epidemiologically important reservoir of resistance genes (resistome, yet prior studies indicate that the true diversity of gut-associated resistomes has been underestimated. To deeply characterize the pediatric gut-associated resistome, we created metagenomic recombinant libraries in an Escherichia coli host using fecal DNA from 22 healthy infants and children (most without recent antibiotic exposure, and performed functional selections for resistance to 18 antibiotics from eight drug classes. Resistance-conferring DNA fragments were sequenced (Illumina HiSeq 2000, and reads assembled and annotated with the PARFuMS computational pipeline. Resistance to 14 of the 18 antibiotics was found in stools of infants and children. Recovered genes included chloramphenicol acetyltransferases, drug-resistant dihydrofolate reductases, rRNA methyltransferases, transcriptional regulators, multidrug efflux pumps, and every major class of beta-lactamase, aminoglycoside-modifying enzyme, and tetracycline resistance protein. Many resistance-conferring sequences were mobilizable; some had low identity to any known organism, emphasizing cryptic organisms as potentially important resistance reservoirs. We functionally confirmed three novel resistance genes, including a 16S rRNA methylase conferring aminoglycoside resistance, and two tetracycline-resistance proteins nearly identical to a bifidobacterial MFS transporter (B. longum s. longum JDM301. We provide the first report to our knowledge of resistance to folate-synthesis inhibitors conferred by a predicted Nudix hydrolase (part of the folate synthesis pathway. This functional metagenomic survey of gut-associated resistomes, the largest of its kind to date, demonstrates that fecal resistomes of healthy children are far more diverse than previously suspected, that clinically relevant resistance genes are present even without recent selective

  5. Unravelling a vicious circle: animal feed marketed in Costa Rica contains irregular concentrations of tetracyclines and abundant oxytetracycline-resistant Gram-positive bacteria.

    Science.gov (United States)

    Granados-Chinchilla, Fabio; Alfaro, Margarita; Chavarría, Guadalupe; Rodríguez, César

    2014-01-01

    Diverse tetracyclines are used to prevent and control bacterial infections in livestock and farmed fish. These drugs are administered through the diet, but farmers seldom check whether feed contains antibiotic-resistant bacteria that may colonise their crops or transfer their resistance traits to species of veterinary relevance. To examine whether antibiotic dosage defines the abundance of antibiotic-resistant bacteria in animal feed, we determined the concentration of parental compounds and epimers of oxytetracycline (OTC), doxycycline, tetracycline and chlortetracycline, as well as the abundance and resistance level of OTC-resistant bacteria in samples of fish (n = 21), poultry (n = 21), swine (n = 21), and shrimp feed (n = 21) marketed in Costa Rica. Fish feed contained the highest amounts of tetracyclines (119-8365 mg kg(-1)) and the largest proportion of bacteria resistant to 10 μg ml(-1) (1.8-92.4%) or 100 μg ml(-1) of OTC (12.5-63.8%). Poultry (78-438 mg kg(-1)) and swine (41-1076 mg kg(-1)) feed had intermediate concentrations of tetracyclines and OTC-resistant bacteria (0.2-66% and 0.3-49%, respectively), whereas shrimp feed showed the lowest amounts of tetracyclines (21.5-50.3 mg kg(-1)), no OTC and no culturable OTC-resistant bacteria. In line with these results, the MIC50 of OTC for 150 isolates from fish and poultry feed was > 256 µg ml(-1), while that of 150 bacteria isolated from swine feed was 192 µg ml(-1). Phenotypic tests, fatty acid profiles and proteotypic analyses by matrix-assisted laser desorption/ionisation-time of flight mass-spectroscopy revealed that most OTC-resistant isolates were Gram-positive bacteria of low G+C% content from the genera Staphylococcus and Bacillus. Clear correlations between OTC dosage and feed colonisation with OTC-resistant bacteria were seen in medicated feed for fish (r = 0.179-0.651). Nonetheless, some unmedicated feed for fish, swine and poultry contained large populations of OTC-resistant bacteria

  6. The lactococcal secondary multidrug transporter LmrP confers resistance to lincosamides, macrolides, streptogramins and tetracyclines

    NARCIS (Netherlands)

    Putman, M; van Veen, HW; Degener, JE; Konings, WN

    2001-01-01

    The active efflux of toxic compounds by (multi)drug transporters is one of the mechanisms that bacteria have developed to resist cytotoxic drugs. The authors describe the role of the lactococcal secondary multidrug transporter LmrP in the resistance to a broad range of clinically important

  7. Pharmacokinetic-Pharmacodynamic Model To Evaluate Intramuscular Tetracycline Treatment Protocols To Prevent Antimicrobial Resistance in Pigs

    DEFF Research Database (Denmark)

    Ahmad, Amais; Græsbøll, Kaare; Christiansen, Lasse Engbo

    2015-01-01

    High instances of antimicrobial resistance are linked to both routine and excessive antimicrobial use, but excessive or inappropriate use represents an unnecessary risk. The competitive growth advantages of resistant bacteria may be amplified by the strain dynamics; in particular, the extent...... to which resistant strains outcompete susceptible strains under antimicrobial pressure may depend not only on the antimicrobial treatment strategies but also on the epidemiological parameters, such as the composition of the bacterial strains in a pig. This study evaluated how variation in the dosing...

  8. Increasing tetracycline concentrations on the performance and communities of mixed microalgae-bacteria photo-bioreactors

    KAUST Repository

    Xiong, Yanghui

    2017-12-11

    This study investigated the impact of varying concentrations of tetracycline on the performance of mixed microalgae-bacteria photo-bioreactors. Photo-bioreactors were assessed for their ability to remove carbon dioxide (CO2) from the biogas of anaerobic membrane bioreactor (anMBR), and nutrients from the anaerobic effluent. The varying concentrations of tetracycline had no impact on the removal of CO2 from biogas. 29% v/v of CO2 was completely removed to generate >20% v/v of oxygen (O2) in all reactors. Removal of nutrients and biomass was not affected at low concentrations of tetracycline (≤150μg/L), but 20mg/L of tetracycline lowered the biomass generation and removal efficiencies of phosphate. Conversely, high chlorophyll a and b content was observed at 20mg/L of tetracycline. High tetracycline level had no impact on the diversity of 18S rRNA gene-based microalgal communities but adversely affected the 16S rRNA gene-based microbial communities. Specifically, both Proteobacteria and Bacteroidetes phyla decreased in relative abundance but not phylum Chloroplast. Additionally, both nitrogen-fixing (e.g. Flavobacterium, unclassified Burkholderiales and unclassified Rhizobiaceae) and denitrifying groups (e.g. Hydrogenophaga spp.) were significantly reduced in relative abundance at high tetracycline concentration. Phosphate-accumulating microorganisms, Acinetobacter spp. and Pseudomonas spp. were similarly reduced upon exposure to high tetracycline concentration. Unclassified Comamonadaceae, however, increased in relative abundance, which correlated with an increase in the abundance of tetracycline resistance genes associated with efflux pump mechanism. Overall, the findings demonstrate that antibiotic concentrations in municipal wastewaters will not significantly affect the removal of nutrients by the mixed microalgae-bacteria photo-bioreactors. However, utilizing such photo-bioreactors as a polishing step for anMBRs that treat wastewaters with high tetracycline

  9. Tetracycline and oxytetracycline resistance determinants detected in Bacillus cereus strains isolated from honey samples Detección de determinantes de resistencia a tetraciclina y oxitetraciclina en cepas de Bacillus cereus aisladas de muestras de miel

    Directory of Open Access Journals (Sweden)

    A. C. López

    2008-12-01

    Full Text Available The aim of this study was to investigate the presence of tetracycline and oxytetracycline resistance determinants in Bacillus cereus strains isolated from honey samples. Of a total of 77 isolates analyzed, 30 (39% exhibited resistance to tetracyclines according to the results of a disk diffusion method. Resistant strains (n=30 were screened by PCR for the presence of the resistant determinants tetK, tetL, tetM, tetO, tetW, otrA and otrB and their MIC values for tetracycline, oxytetracycline and minocycline were assessed. According to the PCR results, 23 isolates (77% presented at least one tetracycline or oxytetracycline resistance determinant. The tetK genotype was present in 10 isolates while the tetL, tetM, and otrA genotypes were present in 3, 2, and 5 isolates, respectively. In addition, 2 isolates of the tetK plus tetM genotype, 1 of the tetK plus tetL genotype, and 1 of the tetK plus otrA genotype were found. All isolates were tetW, tetO and otrB negatives. On the other hand, 7 isolates (23% showed a tetracycline-resistant and/or minocyclineresistant phenotype (MIC but did not carry any of the tet or otr determinants investigated in this study. This research has shown that B. cereus isolates from honey samples contain a variety of tetracycline and oxytetracycline resistance genes, including the tetK and tetL determinants which encode for efflux proteins, and tetM and otrA, which encode for ribosomal protection proteins. These findings indicate that strains isolated from honeys could represent a reservoir for tetracycline resistance genes. To our knowledge, this is the first report of tetracycline-resistant and oxytetracyclineresistant B. cereus strains carrying the tetK determinant, and also the first report of oxytetracycline-resistant and tetracycline- resistant Bacillus species carrying the otrA determinant.El objetivo del presente estudio ha sido investigar la presencia de diversos determinantes de resistencia a tetraciclina y

  10. Increasing Incidence of High-Level Tetracycline-Resistant Neisseria gonorrhoeae due to Clonal Spread and Foreign Import.

    Science.gov (United States)

    Lee, Hyukmin; Kim, Hyunsoo; Kim, Hyo Jin; Suh, Young Hee; Yong, Dongeun; Jeong, Seok Hoon; Lee, Kyungwon; Chong, Yunsop

    2016-03-01

    The detection of high-level tetracycline-resistant strains of Neisseria gonorrhoeae (TRNG) can make important epidemiological contributions that are relevant to controlling infections from this pathogen. In this study, we aimed to determine the incidence of TRNG isolates over time and also to investigate the characteristics and genetic epidemiology of these TRNG isolates in Korea. The antimicrobial susceptibilities of 601 isolates of N. gonorrhoeae from 2004 to 2011 were tested by standard Clinical and Laboratory Standards Institute methods. To determine the molecular epidemiological relatedness, N. gonorrhoeae multi-antigen sequence typing was performed. The incidence of TRNG increased from 2% in 2004 to 21% in 2011. The minimum inhibitory concentration distributions of ceftriaxone and susceptibility of ciprofloxacin in TRNG were different from non-TRNG and varied according to the year of isolation. Most of the TRNG isolates collected from 2004 to 2007 exhibited genetic relatedness, with sequence type (ST) 1798 being the most common. From 2008 to 2011, the STs of the isolates became more variable and introduction of genetically unrelated TRNG were noted. The increased incidence of TRNG strains until 2007 appears to be due, at least in part, to clonal spread. However, we propose that the emergence of various STs since 2008 could be associated with foreign import.

  11. Excretion of antibiotic resistance genes by dairy calves fed milk replacers with varying doses of antibiotics

    OpenAIRE

    Callie H. Thames; Amy ePruden; Robert E. James; Partha P. Ray; Katharine F. Knowlton

    2012-01-01

    Elevated levels of antibiotic resistance genes (ARGs) in soil and water have been linked to livestock farms and in some cases feed antibiotics may select for antibiotic resistant gut microbiota. The purpose of this study was to examine the establishment of ARGs in the feces of calves receiving milk replacer containing no antibiotics versus subtherapeutic or therapeutic doses of tetracycline and neomycin. The effect of antibiotics on calf health was also of interest. Twenty-eight male and fema...

  12. Improved Tet-On and Tet-Off systems for tetracycline-regulated expression of genes in Candida.

    Science.gov (United States)

    Bijlani, Swati; Nahar, Anubhav S; Ganesan, K

    2018-02-01

    Tetracycline-regulated expression of genes is often used for functional analysis of Candida albicans genes. However, the widely used Tet-On system has certain limitations such as prolonged lag time (up to 8 h) for induction and non-uniform expression among the cells. We speculated that poor expression of tetracycline-controlled transactivator (Tet-transactivator) from CaADH1 promoter could be responsible for this, and thus compared the effect of expressing this protein under the control of CaADH1, CaTDH3 and CaRP10 promoters on the expression of GFP from the TET promoter. Only CaRP10 promoter facilitated a more uniform and rapid induction of GFP. However, a high concentration of doxycycline was needed for induction, which is not desirable for assessing certain phenotypes. Tet-Off systems are known to require a low concentration of doxycycline, but a limitation of the widely used Tet-Off system for C. albicans is the use of CaENO1 promoter, which is known to be repressed in the presence of gluconeogenic carbon source, for expression of transactivator. Thus, we have converted the above-mentioned Tet-On systems to Tet-Off systems by site-directed mutagenesis of the Tet-transactivator. Compared to the Tet-On systems, the Tet-Off systems required about 200-fold less concentration of doxycycline for modulation of gene expression. Only the Tet-Off system with CaRP10 promoter driving the expression of transactivator allowed rapid and high level expression of GFP compared to those with CaADH1 or CaTDH3 promoters. The utility of CaRP10 based Tet-On and Tet-Off systems was further validated by the conditional expression of the CaTUP1 gene. We have also adapted these systems for use with Candida tropicalis and find that the Tet-Off system is functional in this species. The Tet systems reported here will be useful for conditional expression of genes in C. albicans as well as C. tropicalis.

  13. The transport of antibiotic resistance genes and residues in groundwater near swine production facilities

    Science.gov (United States)

    Lin, Y. F.; Yannarell, A. C.; Mackie, R. I.; Krapac, I. G.; Chee-Sanford, J. S.; Koike, S.

    2008-12-01

    The use of antibiotics at concentrated animal feeding operations (CAFOs) for disease prevention, disease treatment, and growth promotion can contribute to the spread of antibiotic compounds, their breakdown products, and antibiotic resistant bacteria and/or the genes that confer resistance. In addition, constitutive use of antibiotics at sub-therapeutic levels can select for antibiotic resistance among the bacteria that inhabit animal intestinal tracts, onsite manure treatment facilities, and any environments receiving significant inputs of manure (e.g. through waste lagoon leakage or fertilizer amendments to farm soils). If the antibiotic resistant organisms persist in these new environments, or if they participate in genetic exchanges with the native microflora, then CAFOs may constitute a significant reservoir for the spread of antibiotic resistance to the environment at large. Our results have demonstrated that leakage from waste treatment lagoons can influence the presence and persistence of tetracycline resistance genes in the shallow aquifer adjacent to swine CAFOs, and molecular phylogeny allowed us to distinguish "native" tetracycline resistance genes in control groundwater wells from manure-associated genes introduced from the lagoon. We have also been able to detect the presence of erythromycin resistance genes in CAFO surface and groundwater even though erythromycin is strictly reserved for use in humans and thus is not utilized at any of these sites. Ongoing research, including modeling of particle transport in groundwater, will help to determine the potential spatial and temporal extent of CAFO-derived antibiotic resistance.

  14. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters

    Science.gov (United States)

    Miller, Jennifer H.; Novak, John T.; Knocke, William R.; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1—a Pseudomonas sp.) and thermophilic (Iso T10—a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457–0.829, P digested sludge or thermophilic digested sludge (Spearman rho = 0.130–0.486, P = 0.075–0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and/or horizontal gene transfer between raw sludge bacteria and the digester microbial community. PMID:27014196

  15. Performance and microbial community variations of anaerobic digesters under increasing tetracycline concentrations

    KAUST Repository

    Xiong, Yanghui

    2017-04-01

    The impact of different concentrations of tetracycline on the performance of anaerobic treatment was evaluated. Results revealed that for all of the tested tetracycline concentrations, no major sustained impact on methane production was observed. Instead, a significant increase in propionic acid was observed in the reactor subjected to the highest concentration of tetracycline (20 mg/L). Microbial community analyses suggest that an alternative methanogenic pathway, specifically that of methanol-utilizing methanogens, may be important for ensuring the stability of methane production in the presence of high tetracycline concentrations. In addition, the accumulation of propionate was due to an increase in volatile fatty acids (VFA)-producing bacteria coupled with a reduction in propionate utilizers. An increase in the abundance of tetracycline resistance genes associated with ribosomal protection proteins was observed after 30 days of exposure to high concentrations of tetracycline, while other targeted resistance genes showed no significant changes. These findings suggest that anaerobic treatment processes can robustly treat wastewater with varying concentrations of antibiotics while also deriving value-added products and minimizing the dissemination of associated antibiotic resistance genes.

  16. Bismuth, Metronidazole, and Tetracycline

    Science.gov (United States)

    Helidac® (as a kit containing Bismuth Subsalicylate, Metronidazole, Tetracycline) ... Bismuth, metronidazole, and tetracycline is used along with other ulcer medications to treat duodenal ulcers. It is ...

  17. Cryo-EM structure of the tetracycline resistance protein TetM in complex with a translating ribosome at 3.9-Å resolution.

    Science.gov (United States)

    Arenz, Stefan; Nguyen, Fabian; Beckmann, Roland; Wilson, Daniel N

    2015-04-28

    Ribosome protection proteins (RPPs) confer resistance to tetracycline by binding to the ribosome and chasing the drug from its binding site. Current models for RPP action are derived from 7.2- to 16-Å resolution structures of RPPs bound to vacant or nontranslating ribosomes. Here we present a cryo-electron microscopy reconstruction of the RPP TetM in complex with a translating ribosome at 3.9-Å resolution. The structure reveals the contacts of TetM with the ribosome, including interaction between the conserved and functionally critical C-terminal extension of TetM with a unique splayed conformation of nucleotides A1492 and A1493 at the decoding center of the small subunit. The resolution enables us to unambiguously model the side chains of the amino acid residues comprising loop III in domain IV of TetM, revealing that the tyrosine residues Y506 and Y507 are not responsible for drug-release as suggested previously but rather for intrafactor contacts that appear to stabilize the conformation of loop III. Instead, Pro509 at the tip of loop III is located directly within the tetracycline binding site where it interacts with nucleotide C1054 of the 16S rRNA, such that RPP action uses Pro509, rather than Y506/Y507, to directly dislodge and release tetracycline from the ribosome.

  18. Healing Potentials of Oral Moringa Oleifera Leaves Extract and Tetracycline on Methicillin Resistant Staphylococcus Aureus Infected Wounds of Wistar rats.

    Science.gov (United States)

    Eyarefe, Oghenemega D; Idowu, Aderayo; Afolabi, Jeremiah M

    2015-12-20

    The effects of oral dose of aqueous extract of Moringa oleifera and tetracycline antibiotics on cutaneous wounds infected with Staphylococcus aureus were studied in eighteen adult wistar rats (159±31.5g) randomized into three groups: Group A, n = 6, Moringa oleifera-(300 mg/kg). Group B, n = 6, tetracycline (9.4 mg/kg) and Group C, n = 6, Sterile water (control). Six millimetres diameter nape wound, created on each rat under 2% xylazine (5 mg/kg) and 5% ketamine (35 mg/kg), was contaminated with Staphylococcus aureus (108 Colony Forming Unit (CFU). Following infection, treatment was commenced with daily oral dose of test preparations and the wounds were evaluated every other day i.e., day 3, 5, 7, 9, 11, 13 and 15 for wetness (wound exudation), wound edge oedema, hyperaemia, granulation tissues and contraction (diameter). Severe wound exudation existed in all the groups between days 0-3 (p = 1.00). A significantly less wound exudation was observed at days 3-5 (p = 0.000) and 5-9 (p = 0.003) (ControlMoringa). Wound edge oedema was significantly less on days 5-9 (p = 0.000) and 9-15 (p = 0.001) (ControlMoringaMoringa Moringa> Tetracycline). Differences in wound diameter was not significant except at days 5-9 (p = 0.013) (Control> Moringa >Tetracycline). Oral doses of Moringa oleifera extract (300mg/kg) and tetracycline (9.4mg/kg) are not effective as antimicrobial or immune-boosting agents to enhance healing of wounds infected with Staphylococcus aureus and hence not recommended for rapid clearance of Staphylococcus aureus infected wounds.

  19. dfrA25, a novel trimethoprim resistance gene from Salmonella Agona isolated from a human urine sample in Brazil

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Peirano, Gisele; Aarestrup, Frank Møller

    2006-01-01

    Objectives: To describe a novel trimethoprim resistance gene, designated dfrA25, which was detected as a gene cassette within a class 1 integron in Salmonella Agona. Methods: The gene was cloned into Escherichia coli MT102 and resistance to 10 different antimicrobial drugs was measured. A phyloge...... a dihydrofolate reductase of 157 amino acids with closest identity (85%) to dfrA5 dihydrofolate reductase. dfrA25 was located on a transferable plasmid (similar to 150 kb) that also harboured the tetracycline resistance gene tet(A)....

  20. Effect of tetracycline on transfer and establishment of the tetracycline-inducible conjugative transposon Tn916 in the guts of gnotobiotic rats

    DEFF Research Database (Denmark)

    Bahl, Martin I.; Sørensen, Søren J.; Hansen, Lars H.

    2004-01-01

    We have investigated the transfer of Tn916 among strains of Enterococcus faecalis OG1 colonizing in the intestines of gnotobiotic rats. This animal model allows a low limit of detection and efficient colonization of the chosen bacteria. The animals continuously received tetracycline in drinking...... water. A tetracycline-sensitive recipient strain was allowed to colonize the animals before the resistant donor was introduced. The numbers of donors, recipients, and transconjugants in fecal samples and intestinal segments were estimated. The bioavailable amounts of tetracycline in fecal samples...... and intestinal segments were monitored by using bacterial biosensors carrying a transcriptional fusion of a tetracycline-regulated promoter and a lacZ reporter gene. Chromosomal locations of Tn916 in transconjugants isolated either from the same animal or from different animals were compared by Southern blot...

  1. Characterization of Antibiotic Resistance Genes from Lactobacillus Isolated from Traditional Dairy Products.

    Science.gov (United States)

    Guo, Huiling; Pan, Lin; Li, Lina; Lu, Jie; Kwok, Laiyu; Menghe, Bilige; Zhang, Heping; Zhang, Wenyi

    2017-03-01

    Lactobacilli are widely used as starter cultures or probiotics in yoghurt, cheese, beer, wine, pickles, preserved food, and silage. They are generally recognized as safe (GRAS). However, recent studies have shown that some lactic acid bacteria (LAB) strains carry antibiotic resistance genes and are resistant to antibiotics. Some of them may even transfer their intrinsic antibiotic resistance genes to other LAB or pathogens via horizontal gene transfer, thus threatening human health. A total of 33 Lactobacillus strains was isolated from fermented milk collected from different areas of China. We analyzed (1) their levels of antibiotic resistance using a standardized dilution method, (2) their antibiotic resistance gene profiles by polymerase chain reaction (PCR) using gene-specific primers, and (3) the transferability of some of the detected resistance markers by a filter mating assay. All Lactobacillus strains were found to be resistant to vancomycin, but susceptible to gentamicin, linezolid, neomycin, erythromycin, and clindamycin. Their susceptibilities to tetracycline, kanamycin, ciprofloxacin, streptomycin, quinupristin/dalfopristin, trimethoprim, ampicillin, rifampicin, and chloramphenicol was different. Results from our PCR analysis revealed 19 vancomycin, 10 ciprofloxacin, and 1 tetracycline-resistant bacteria that carried the van(X), van(E), gyr(A), and tet(M) genes, respectively. Finally, no transferal of the monitored antibiotic resistance genes was observed in the filter mating assay. Taken together, our study generated the antibiotic resistance profiles of some milk-originated lactobacilli isolates and preliminarily assessed their risk of transferring antibiotic gene to other bacteria. The study may provide important data concerning the safe use of LAB. © 2017 Institute of Food Technologists®.

  2. A new chloramphenicol and florfenicol resistance gene flanked by two integron structures in Salmonella typhimurium DT104.

    Science.gov (United States)

    Arcangioli, M A; Leroy-Sétrin, S; Martel, J L; Chaslus-Dancla, E

    1999-05-15

    A new chloramphenicol resistance gene from Salmonella typhimurium DT104, designated floR, also conferring resistance to florfenicol, was characterized. Sequence analysis of the deduced FloR protein suggested that it belongs to the 12-TMS (transmembrane segments) multidrug efflux pumps family. The floR gene, and the downstream sequenced tetR and tetA tetracycline resistance genes, were surrounded by two class 1 integrons. The first one contained the resistance gene aadA2 and a deleted sulI resistance gene. The second one contained the beta-lactamase gene pse1 and a complete sulI gene. Thus, the floR gene is included in a multiresistance locus of at least 12.5 kb. Its particular organization and chromosomal location could be involved in the antibioresistance pattern stability of the DT104 Salmonella typhimurium strains.

  3. Molecular typing, antibiotic resistance, virulence gene and biofilm formation of different Salmonella enterica serotypes.

    Science.gov (United States)

    Turki, Yousra; Mehr, Ines; Ouzari, Hadda; Khessairi, Amel; Hassen, Abdennaceur

    2014-01-01

    Salmonella enterica isolates representing commonly isolated serotypes in Tunisia were analyzed using genotyping and phenotyping methods. ERIC and ITS-PCR applied to 48 Salmonella spp. isolates revealed the presence of 12 and 10 different profiles, respectively. The distribution of profiles among serotypes demonstrated the presence of strains showing an identical fingerprinting pattern. All Salmonella strains used in this study were positive for the sdiA gene. Three Salmonella isolates belonging to serotypes Anatum, Enteritidis and Amsterdam were negative for the invA gene. The spvC gene was detected in thirteen isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Gallinarum and Montevideo. Antibiotic resistance was frequent among the recovered Salmonella isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Zanzibar and Derby. The majority of these isolates exhibited resistance to at least two antibiotic families. Four multidrug-resistant isolates were recovered from food animals and poultry products. These isolates exhibited not only resistance to tetracycline, sulphonamides, and ampicillin, but also have shown resistance to fluoroquinolones. Common resistance to nalidixic acid, ciprofloxacin and ofloxacin in two S. Anatum and S. Zanzibar strains isolated from raw meat and poultry was also obtained. Furthermore, wastewater and human isolates exhibited frequent resistance to nalidixic acid and tetracycline. Of all isolates, 33.5% were able to form biofilm.

  4. Antibiotic resistance genes and virulence factors in Enterococcus faecium and Enterococcus faecalis from diseased farm animals: pigs, cattle and poultry.

    Science.gov (United States)

    Seputiene, V; Bogdaite, A; Ruzauskas, M; Suziedeliene, E

    2012-01-01

    Eighty enterococcal isolates (E. faecium, n = 38, E. faecalis, n = 42) from diseased farm animals (swine, cattle, poultry) in Lithuania have been studied for the prevalence of antibiotic resistance and for resistance and virulence genetic determinants. 86% of E. faecium and 71% of E. faecalis isolates were multidrug resistant (resistant to three or more unrelated antibiotics). Resistance to aminoglycosides, tetracycline and erythromycin was found most frequently in both species (61%, 69%) and was linked to aph(3')-IIIa, aac(6')-Ie-aph(2")-Ia, ant(6)-Ia (aminoglycoside resistance), tetM, tetL (tetracycline resistance), ermA, ermB (erythromycin resistance) gene combinations, which were supplemented with chloramphenicol resistance genes catA7, catA8 (E. faecalis) and catA9 (E. faecium). All E. faecalis isolates harboured genes coding for virulence factors agg, esp, fsr gelE alone or in combinations with the high prevalence of esp gene in isolates from cattle (63%) and pigs (79%). The origin-dependent incidence of agg gene variants prgB and asp1 was observed. The results indicate the existence of a large pool of potentially virulent and multidrug resistant E. faecalis in diseased farm animals posing risk to humans.

  5. Anthropogenic antibiotic resistance genes mobilization to the polar regions

    Directory of Open Access Journals (Sweden)

    Jorge Hernández

    2016-12-01

    Full Text Available Anthropogenic influences in the southern polar region have been rare, but lately microorganisms associated with humans have reached Antarctica, possibly from military bases, fishing boats, scientific expeditions, and/or ship-borne tourism. Studies of seawater in areas of human intervention and proximal to fresh penguin feces revealed the presence of Escherichia coli strains least resistant to antibiotics in penguins, whereas E. coli from seawater elsewhere showed resistance to one or more of the following antibiotics: ampicillin, tetracycline, streptomycin, and trim-sulfa. In seawater samples, bacteria were found carrying extended-spectrum β-lactamase (ESBL-type CTX-M genes in which multilocus sequencing typing (MLST showed different sequence types (STs, previously reported in humans. In the Arctic, on the contrary, people have been present for a long time, and the presence of antibiotic resistance genes (ARGs appears to be much more wide-spread than was previously reported. Studies of E coli from Arctic birds (Bering Strait revealed reduced susceptibility to antibiotics, but one globally spreading clone of E. coli genotype O25b-ST131, carrying genes of ESBL-type CTX-M, was identified. In the few years between sample collections in the same area, differences in resistance pattern were observed, with E. coli from birds showing resistance to a maximum of five different antibiotics. Presence of resistance-type ESBLs (TEM, SHV, and CTX-M in E. coli and Klebsiella pneumoniae was also confirmed by specified PCR methods. MLST revealed that those bacteria carried STs that connect them to previously described strains in humans. In conclusion, bacteria previously related to humans could be found in relatively pristine environments, and presently human-associated, antibiotic-resistant bacteria have reached a high global level of distribution that they are now found even in the polar regions.

  6. Resistance of potential probiotic lactic acid bacteria and bifidobacteria of African and European origin to antimicrobials: Determination and transferability of the resistance genes to other bacteria

    DEFF Research Database (Denmark)

    Ouoba, Labia Irene Ivette; Lei, Vicki; Jensen, Lars Bogø

    2008-01-01

    antimicrobials, detection of resistance genes by PCR reactions using specific primers and sequencing of positive amplicons. The ability of Lb. reuteri from Africa to transfer the erythromycin resistance gene erm(B) to closely related bacteria was investigated by conjugation. Variations were observed and high...... found in Lb. reuteri L4: 12002 from Africa contained a homologous sequence to previously published sequences. This gene could be transferred in vitro to enterococci. Higher prevalence of phenotypic resistance for aminoglycoside was found in isolates from Europe. (C) 2007 Elsevier B.V. All rights...... levels of intrinsic resistance were found among the tested species. Positive amplicons were obtained for resistance genes encoding aminoglycoside (aph(3')-III, aadA, aadE) and tetracycline (tet(S)) from isolates from Europe and macrolide (erm(B)) from an isolate from Africa. However, only the erm(B) gene...

  7. Survival of antibiotic resistant bacteria and horizontal gene transfer control antibiotic resistance gene content in anaerobic digesters

    Directory of Open Access Journals (Sweden)

    Jennifer Hafer Miller

    2016-03-01

    Full Text Available Understanding fate of antibiotic resistant bacteria (ARB versus their antibiotic resistance genes (ARGs during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1- a Pseudomonas sp. and thermophilic (Iso T10- a Bacillus sp. anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic or 1-log above baseline (mesophilic while levels of the ARG present in the spiked isolate (tet(G remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O, tet(W, and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457 to 0.829, P<0.05 with the raw feed sludge. There was no correlation in tet(O or tet(W ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130 to 0.486, P = 0.075 to 0.612. However, in the thermophilic digester, the tet(O and tet(W ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and

  8. Prevalence of antibiotic resistance genes of wastewater and surface water in livestock farms of Jiangsu Province, China.

    Science.gov (United States)

    Chen, Biao; Hao, Lijun; Guo, Xinyan; Wang, Na; Ye, Boping

    2015-09-01

    The overuse of antibiotics in livestock farms is general, leading to a wide distribution of antibiotic resistance genes (ARGs) in aquatic environment adjacent to livestock farms. However, researches of the distribution and types of ARGs in aquatic environment of China are still in the initial stage. In this study, wastewater and surface water samples were collected from 12 livestock farms (four pig farms, four cattle farms, and four chicken farms) in Jiangsu Province of China. The prevalence, abundance, and distribution of 22 ARGs were investigated, which were categorized into six groups, including nine tetracyclin resistance genes, three sulfonamides resistance genes, three quinolone resistance genes, two macrolide resistance genes, three aminoglycoside resistance genes, and two multidrug resistance genes, employing quantitative real-time PCR (qPCR). The results suggested that all of the 22 ARGs were detected in samples. Sul1, sul2, and tetM were the most abundant with the average concentration of 3.84 × 10(1) copies/16S recombinant RNA (rRNA) gene copies, 1.62 × 10(1) copies/16S rRNA gene copies, 2.33 × 10(1) copies/16S rRNA gene copies, respectively. Principle component analysis revealed that the comprehensive pollution of ARGs in northern Jiangsu was more serious. ARGs in wastewater were more abundant when compared to that in surface water. A preliminary study regarding the fate of ARGs after an aerobiotic process showed that tetA, tetC, sul1, sul2, oqxB, and qnrS were significantly increased. And, among the tetracycline resistance genes, the efflux pump genes were enriched while the ribosomal protection protein encoding genes were decreased in the aerobiotic process. The prevalance of ARGs in water environment is of concern; more surveillance is required to determine the pollution level and pattern of antibiotic resistance genes.

  9. Pharmacodynamics of Doxycycline and Tetracycline against Staphylococcus pseudintermedius: Proposal of Canine-Specific Breakpoints for Doxycycline

    Science.gov (United States)

    Papich, Mark G.; Turnidge, John; Guardabassi, Luca

    2013-01-01

    Doxycycline is a tetracycline that has been licensed for veterinary use in some countries, but no clinical breakpoints are available for veterinary pathogens. The objectives of this study were (i) to establish breakpoints for doxycycline and (ii) to evaluate the use of tetracycline as a surrogate to predict the doxycycline susceptibility of Staphylococcus pseudintermedius isolates. MICs and inhibition zone diameters were determined for 168 canine S. pseudintermedius isolates according to Clinical and Laboratory Standards Institute (CLSI) standards. Tetracycline resistance genes were detected by PCR, and time-kill curves were determined for representative strains. In vitro pharmacodynamic and target animal pharmacokinetic data were analyzed by Monte Carlo simulation (MCS) for the development of MIC interpretive criteria. Optimal zone diameter breakpoints were defined using the standard error rate-bounded method. The two drugs displayed bacteriostatic activity and bimodal MIC distributions. Doxycycline was more active than tetracycline in non-wild-type strains. MCS and target attainment analysis indicated a certainty of ≥90% for attaining an area under the curve (AUC)/MIC ratio of >25 with a standard dosage of doxycycline (5 mg/kg of body weight every 12 h) for strains with MICs of ≤0.125 μg/ml. Tetracycline predicted doxycycline susceptibility, but current tetracycline breakpoints were inappropriate for the interpretation of doxycycline susceptibility results. Accordingly, canine-specific doxycycline MIC breakpoints (susceptible, ≤0.125 μg/ml; intermediate, 0.25 μg/ml; resistant, ≥0.5 μg/ml) and zone diameter breakpoints (susceptible, ≥25 mm; intermediate, 21 to 24 mm; resistant, ≤20 mm) and surrogate tetracycline MIC breakpoints (susceptible, ≤0.25 μg/ml; intermediate, 0.5 μg/ml; resistant, ≥1 μg/ml) and zone diameter breakpoints (susceptible, ≥23 mm; intermediate, 18 to 22 mm; resistant, ≤17 mm) were proposed based on the data generated

  10. Distribution of genes related to antimicrobial resistance in different oral environments: a systematic review.

    Science.gov (United States)

    Moraes, Ludmila Coutinho; Só, Marcus Vinícius Reis; Dal Pizzol, Tatiane da Silva; Ferreira, Maria Beatriz Cardoso; Montagner, Francisco

    2015-04-01

    The oral cavity is the main source of microorganisms for odontogenic infections. It is important to perform an extensive analysis regarding the reports on the presence of bacteria that carry resistance genes to antimicrobial agents. The aim of the study was to verify the reports on the distribution of genes associated with resistance to antibiotics prescribed in dentistry in different human oral sites. A systematic review was conducted in electronic databases and gray literature to analyze clinical studies that detected genes of bacterial resistance to antibiotics in saliva, supragingival biofilm, and endodontic infections. Data regarding the research group, geographic location, sample source, number of subjects, methods for sample analysis, the targeted gene groups, and the detection rates were collected. Descriptive data analysis was performed. Preliminary analysis was performed in 152 titles; 50 abstracts were reviewed, and 29 full texts were obtained. Nine articles matched the inclusion criteria (saliva = 2, supragingival biofilm = 1, and endodontic infections = 6). The presence of 33 different targeted genes was evaluated. The most frequently investigated groups of genes were tetracycline and lactamics (tetM, tetQ, tetW, and cfxA). There was a wide range for the detection rates of each resistance gene among studies and for each specific gene group. This systematic review highlights the presence of resistance genes to antimicrobial agents in saliva, dental biofilm, and endodontic infections, especially for tetracycline and lactamics. There is a lack of reports on the presence of genes and resulting outcomes obtained through the therapeutic approaches for infection control. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Fungal treatment for the removal of antibiotics and antibiotic resistance genes in veterinary hospital wastewater.

    Science.gov (United States)

    Lucas, D; Badia-Fabregat, M; Vicent, T; Caminal, G; Rodríguez-Mozaz, S; Balcázar, J L; Barceló, D

    2016-06-01

    The emergence and spread of antibiotic resistance represents one of the most important public health concerns and has been linked to the widespread use of antibiotics in veterinary and human medicine. The overall elimination of antibiotics in conventional wastewater treatment plants is quite low; therefore, residual amounts of these compounds are continuously discharged to receiving surface waters, which may promote the emergence of antibiotic resistance. In this study, the ability of a fungal treatment as an alternative wastewater treatment for the elimination of forty-seven antibiotics belonging to seven different groups (β-lactams, fluoroquinolones, macrolides, metronidazoles, sulfonamides, tetracyclines, and trimethoprim) was evaluated. 77% of antibiotics were removed after the fungal treatment, which is higher than removal obtained in conventional treatment plants. Moreover, the effect of fungal treatment on the removal of some antibiotic resistance genes (ARGs) was evaluated. The fungal treatment was also efficient in removing ARGs, such as ermB (resistance to macrolides), tetW (resistance to tetracyclines), blaTEM (resistance to β-lactams), sulI (resistance to sulfonamides) and qnrS (reduced susceptibility to fluoroquinolones). However, it was not possible to establish a clear link between concentrations of antibiotics and corresponding ARGs in wastewater, which leads to the conclusion that there are other factors that should be taken into consideration besides the antibiotic concentrations that reach aquatic ecosystems in order to explain the emergence and spread of antibiotic resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Pharmacodynamics of doxycycline and tetracycline against Staphylococcus pseudintermedius

    DEFF Research Database (Denmark)

    Maaland, Marit Gaastra; Papich, Mark G.; Turnidge, John

    2013-01-01

    doxycycline susceptibility of Staphylococcus pseudintermedius.MICs and inhibition zone diameters were determined according to CLSI standards in 168 canine S. pseudintermedius isolates. Tetracycline resistance genes were detected by PCR, and time-kill curves were determined for representative strains. In vitro...

  13. Distribution and characterization of ampicillin- and tetracycline-resistant Escherichia coli from feedlot cattle fed subtherapeutic antimicrobials

    Directory of Open Access Journals (Sweden)

    Yanke L Jay

    2011-04-01

    Full Text Available Abstract Background Feedlot cattle in North America are routinely fed subtherapeutic levels of antimicrobials to prevent disease and improve the efficiency of growth. This practice has been shown to promote antimicrobial resistance (AMR in subpopulations of intestinal microflora including Escherichia coli. To date, studies of AMR in feedlot production settings have rarely employed selective isolation, therefore yielding too few AMR isolates to enable characterization of the emergence and nature of AMR in E. coli as an indicator bacterium. E. coli isolates (n = 531 were recovered from 140 cattle that were housed (10 animals/pen in 14 pens and received no dietary antimicrobials (control - 5 pens, CON, or were intermittently administered subtherapeutic levels of chlortetracycline (5 pens-T, chlortetracycline + sulfamethazine (4 pens-TS, or virginiamycin (5 pens-V for two separate periods over a 9-month feeding period. Phenotype and genotype of the isolates were determined by susceptibility testing and pulsed field gel electrophoresis and distribution of characterized isolates among housed cattle reported. It was hypothesized that the feeding of subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR E. coli from cattle. Results Overall, patterns of antimicrobial resistance expressed by E. coli isolates did not change among diet groups (CON vs. antibiotic treatments, however; isolates obtained on selective plates (i.e., MA,MT, exhibited multi-resistance to sulfamethoxazole and chloramphenicol more frequently when obtained from TS-fed steers than from other treatments. Antibiograms and PFGE patterns suggested that AMR E. coli were readily transferred among steers within pens. Most MT isolates possessed the tet(B efflux gene (58.2, 53.5, 40.8, and 50.6% of isolates from CON, T, TS, and V steers, respectively whereas among the MA (ampicillin-resistant isolates, the tem1-like determinant was predominant (occurring in 50, 66

  14. Characterization and Horizontal Transfer of Antimicrobial Resistance Genes and Integrons in Bacteria Isolated from Cooked Meat Products in China.

    Science.gov (United States)

    Yu, Tao; Jiang, Xiaobing; Liang, Yu; Zhu, Yanping; Tian, Jinhe; Ying, Hao; Wang, Xuannian; Shi, Lei

    2017-11-17

    The aim of this study was to investigate antimicrobial resistance and the presence and transferability of corresponding resistance genes and integrons in bacteria isolated from cooked meat samples in the People's Republic of China. A total of 150 isolates (22 species belonging to 15 genera) were isolated from 49 samples. Resistance of these isolates to antimicrobials was commonly observed; 42.7, 36.0, and 25.3% of the isolates were resistant to tetracycline, streptomycin, and ampicillin, respectively. Multidrug resistance was observed in 41 (27.3%) of the isolates. Sixteen resistance genes, i.e., blaTEM-1 and blaCTX-M-14 (β-lactams), aac(3)-IIa (gentamicin), strA and strB (streptomycin), qnrB and qnrS (fluoroquinolone), sul1, sul2, and sul3 (sulfamethoxazole), cat1 and cat2 (chloramphenicol), and tetM, tetA, tetS, and tetB (tetracycline), were found in 54 isolates. One isolate of Pseudomonas putida carried qnrB, and sequence analysis of the PCR product revealed 96% identity to qnrB2. The qnr genes were found coresiding and were cotransferred with bla genes in two isolates. Twelve isolates were positive for the class 1 integrase gene, and four isolates carried the class 2 integrase gene. However, no class 3 integrase gene was detected. One isolate of Proteus mirabilis carried dfrA32-ereA-aadA2, and this unusual array could be transferred to Escherichia coli. Nonclassic class 1 integrons lacking qacEΔ1 and sul1 genes were found in 2 of the 12 intI1-positive isolates. Our results revealed the presence of multidrug-resistant bacteria in cooked meats and the presence and transferability of resistance genes in some isolates, suggesting that cooked meat products may act as reservoirs of drug-resistant bacteria and may facilitate the spread of resistance genes.

  15. Evolution of corresponding resistance genes in the water of fish tanks with multiple stresses of antibiotics and heavy metals.

    Science.gov (United States)

    He, Xiaolin; Xu, Yanbin; Chen, Jinliang; Ling, Jiayin; Li, Yafei; Huang, Lu; Zhou, Xiao; Zheng, Li; Xie, Guangyan

    2017-11-01

    Abuse of antibiotics and heavy metals in aquaculture has been widely concerned and might aggravate the spread of resistance genes in environment. To investigate the occurrence and proliferation of antibiotic resistance genes (ARGs) and heavy metal resistance genes (HMRGs), three commonly used antibiotics (tetracycline, sulfanilamide, cefotaxime) and two heavy metals (Zn and Cu) were designed to add individually or jointly in nine fish tanks including five individual exposure tanks of tetracycline (tet), sulfanilamide (sul), cefotaxime (cef), Cu, Zn and four combination exposure tanks of tetracycline + sulfanilamide (tet + sul), tetracycline + sulfanilamide + cefotaxime (tet + sul + cef), tetracycline + sulfanilamide + Cu (tet + sul + Cu), tetracycline + sulfanilamide + Zn (tet + sul + Zn) as well as the control during the experiment period of 180 days. Nineteen ARGs (tetA, tetB, tetC, tetD, tetE, tetG, tetM, tetO, tetQ, tetS, tetW, tetX, tetY, sul1, sul2, sul3, blaDHA, blaMOX, blaFOX), two HMRGs (copA, czcA) and the class 1 integron gene (intI 1) in fish tanks water were investigated. The results showed that the residual rate of antibiotics and heavy metals ranged from 0.03% to 2.46% and 9.25%-52.97%, respectively, positively related to their original concentration and types. Tetracycline resistance genes were more sensitive to antibiotics and easier to be induced and developed than sulfanilamide resistance genes and AmpC β-lactamase resistance genes. The total relative abundances of ARGs in combined stresses exposure tanks (tet + sul, tet + sul + cef, tet + sul + Cu, tet + sul + Zn) were about 1.01-1.55 times more than the sum of their individual ones. The co-selective effects of cefotaxime on the abundance and diversity of tetracycline resistance genes were stronger than Zn and Cu. Besides, multivariate correlation analysis revealed that tetO, tetQ, tetW and sul3 were in significant correlation with the concentrations of

  16. Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China.

    Science.gov (United States)

    Yang, Yuyi; Cao, Xinhua; Lin, Hui; Wang, Jun

    2016-11-01

    Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg-1 (dry weight (dw)) with mean value of 278.21 μg kg-1 dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg-1 dw, mean value of 195.70 μg kg-1 dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p  tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.

  17. Antimicrobial susceptibility and presence of resistance genes in staphylococci from poultry

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Agersø, Yvonne; Ahrens, Peter

    2000-01-01

    The species distribution, susceptibility to 19 antimicrobial agents and presence of selected genes encoding resistance to macrolides, streptogramins and tetracyclines were examined among 118 staphylococcal isolates from infections of poultry in Denmark. Isolates were identified using a combination...... of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant...... to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin...

  18. Fate of antibiotic resistant cultivable heterotrophic bacteria and antibiotic resistance genes in wastewater treatment processes.

    Science.gov (United States)

    Zhang, Songhe; Han, Bing; Gu, Ju; Wang, Chao; Wang, Peifang; Ma, Yanyan; Cao, Jiashun; He, Zhenli

    2015-09-01

    Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants of environmental concern. Heterotrophic bacteria in activated sludge have an important role in wastewater treatment plants (WWTPs). However, the fate of cultivable heterotrophic ARB and ARGs in WWPTs process remains unclear. In the present study, we investigated the antibiotic-resistant phenotypes of cultivable heterotrophic bacteria from influent and effluent water of three WWTPs and analysed thirteen ARGs in ARB and in activated sludge from anoxic, anaerobic and aerobic compartments. From each influent or effluent sample of the three plants, 200 isolates were randomly tested for susceptibility to 12 antibiotics. In these samples, between 5% and 64% isolates showed resistance to >9 antibiotics and the proportion of >9-drug-resistant bacteria was lower in isolates from effluent than from influent. Eighteen genera were identified in 188 isolates from influent (n=94) and effluent (n=94) of one WWTP. Six genera (Aeromonas, Bacillus, Lysinibacillus, Microbacterium, Providencia, and Staphylococcus) were detected in both influent and effluent samples. Gram-negative and -positive isolates dominated in influent and effluent, respectively. The 13 tetracycline-, sulphonamide-, streptomycin- and β-lactam-resistance genes were detected at a higher frequency in ARB from influent than from effluent, except for sulA and CTX-M, while in general, the abundances of ARGs in activated sludge from two of the three plants were higher in aerobic compartments than in anoxic ones, indicating abundant ARGs exit in the excess sledges and/or in uncultivable bacteria. These findings may be useful for elucidating the effect of WWTP on ARB and ARGs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. RESISTANCE-RELATED GENE TRANSCRIPTION AND ...

    African Journals Online (AJOL)

    jdx

    2014-02-05

    related gene, antioxidant enzyme activity. INTRODUCTION ... oxygen and nitrogen species, through changes in ion flux across the plasma ... A better understanding of the gene network underlying anthracnose resistance in ...

  20. Tetracycline-resistant coliforms in the effluent of the main sewage treatment plant in Hamilton, Ontario - do they have a common ancestral strain?

    Science.gov (United States)

    Sorger, George J; Quinn, James S

    2010-07-01

    Sewage, a major source of bacterial contamination of the environment, can be an important health hazard. The presence of antibiotic-resistant bacteria in sewage can exacerbate this problem. The sources of antibiotic-resistant bacteria in sewage are, for this reason, worth identifying and addressing. The bacterial flora in the effluent of the Woodward Avenue Wastewater Treatment Plant (WAWTP) in Hamilton, Ontario, Canada, contains many antibiotic-resistant coliforms. Here we ask, are the antibiotic resistance genes in the coliforms in the effluent of WAWTP descended from a recent common ancestor strain? If so, the source could be identified and eliminated. If, on the other hand, the antibiotic resistance genes in the bacterial flora of the WAWTP have more than one origin, identification and elimination of the source(s) could be difficult. There was considerable diversity of antibiotic resistance patterns and antibiotic resistance genes among the effluent and influent coliform isolates of the WAWTP, suggesting multiple genetic ancestry. The patterns of horizontal transmissibility and sequence differences in the genes tetA and tetE among these coliform isolates also suggest that they have no one predominant ancestral strain. Using the same logic, the evidence presented here is not compatible with a single ancestral origin of the antibiotic resistance genes in the isolates described herein.

  1. Abundance and persistence of antibiotic resistance genes in livestock farms: a comprehensive investigation in eastern China.

    Science.gov (United States)

    Cheng, Weixiao; Chen, Hong; Su, Chao; Yan, Shuhai

    2013-11-01

    Increases of antibiotic resistance genes in the environment may pose a threat to public health. The purpose of this study was to investigate the abundance and diversity of tetracycline (tet) and sulfonamide (sul) resistance genes in eight livestock farms in Hangzhou, eastern China. Ten tet genes (tetA, tetB, tetC, tetG, tetL, tetM, tetO, tetQ, tetW, and tetX), two sul genes (sulI and sulII), and one genetic element associated with mobile antibiotic resistance genes [class 1 integron (intI1)] were quantified by real-time polymerase chain reaction. No significant difference was found in the abundance of the tet and sul genes in various scales of pig, chicken, and duck farms (P>0.05). The average abundance of ribosomal protection protein genes (tetQ, tetM, tetW, and tetO) in the manure and wastewater samples was higher than most of the efflux pump genes (tetA, tetB, tetC, and tetL) and enzymatic modification gene (tetX) (Pantibiotic resistance emanating from agricultural activities. © 2013.

  2. Stormwater loadings of antibiotic resistance genes in an urban stream.

    Science.gov (United States)

    Garner, Emily; Benitez, Romina; von Wagoner, Emily; Sawyer, Richard; Schaberg, Erin; Hession, W Cully; Krometis, Leigh-Anne H; Badgley, Brian D; Pruden, Amy

    2017-10-15

    Antibiotic resistance presents a critical public health challenge and the transmission of antibiotic resistance via environmental pathways continues to gain attention. Factors driving the spread of antibiotic resistance genes (ARGs) in surface water and sources of ARGs in urban stormwater have not been well-characterized. In this study, five ARGs (sul1, sul2, tet(O), tet(W), and erm(F)) were quantified throughout the duration of three storm runoff events in an urban inland stream. Storm loads of all five ARGs were significantly greater than during equivalent background periods. Neither fecal indicator bacteria measured (E. coli or enterococci) was significantly correlated with sul1, sul2, or erm(F), regardless of whether ARG concentration was absolute or normalized to 16S rRNA levels. Both E. coli and enterococci were correlated with the tetracycline resistance genes, tet(O) and tet(W). Next-generation shotgun metagenomic sequencing was conducted to more thoroughly characterize the resistome (i.e., full complement of ARGs) and profile the occurrence of all ARGs described in current databases in storm runoff in order to inform future watershed monitoring and management. Between 37 and 121 different ARGs were detected in each stream sample, though the ARG profiles differed among storms. This study establishes that storm-driven transport of ARGs comprises a considerable fraction of overall downstream loadings and broadly characterizes the urban stormwater resistome to identify potential marker ARGs indicative of impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Metagenomic profiling of antibiotic resistance genes and mobile genetic elements in a tannery wastewater treatment plant.

    Directory of Open Access Journals (Sweden)

    Zhu Wang

    Full Text Available Antibiotics are often used to prevent sickness and improve production in animal agriculture, and the residues in animal bodies may enter tannery wastewater during leather production. This study aimed to use Illumina high-throughput sequencing to investigate the occurrence, diversity and abundance of antibiotic resistance genes (ARGs and mobile genetic elements (MGEs in aerobic and anaerobic sludge of a full-scale tannery wastewater treatment plant (WWTP. Metagenomic analysis showed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria dominated in the WWTP, but the relative abundance of archaea in anaerobic sludge was higher than in aerobic sludge. Sequencing reads from aerobic and anaerobic sludge revealed differences in the abundance of functional genes between both microbial communities. Genes coding for antibiotic resistance were identified in both communities. BLAST analysis against Antibiotic Resistance Genes Database (ARDB further revealed that aerobic and anaerobic sludge contained various ARGs with high abundance, among which sulfonamide resistance gene sul1 had the highest abundance, occupying over 20% of the total ARGs reads. Tetracycline resistance genes (tet were highly rich in the anaerobic sludge, among which tet33 had the highest abundance, but was absent in aerobic sludge. Over 70 types of insertion sequences were detected in each sludge sample, and class 1 integrase genes were prevalent in the WWTP. The results highlighted prevalence of ARGs and MGEs in tannery WWTPs, which may deserve more public health concerns.

  4. Metagenomic profiling of antibiotic resistance genes and mobile genetic elements in a tannery wastewater treatment plant.

    Science.gov (United States)

    Wang, Zhu; Zhang, Xu-Xiang; Huang, Kailong; Miao, Yu; Shi, Peng; Liu, Bo; Long, Chao; Li, Aimin

    2013-01-01

    Antibiotics are often used to prevent sickness and improve production in animal agriculture, and the residues in animal bodies may enter tannery wastewater during leather production. This study aimed to use Illumina high-throughput sequencing to investigate the occurrence, diversity and abundance of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in aerobic and anaerobic sludge of a full-scale tannery wastewater treatment plant (WWTP). Metagenomic analysis showed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria dominated in the WWTP, but the relative abundance of archaea in anaerobic sludge was higher than in aerobic sludge. Sequencing reads from aerobic and anaerobic sludge revealed differences in the abundance of functional genes between both microbial communities. Genes coding for antibiotic resistance were identified in both communities. BLAST analysis against Antibiotic Resistance Genes Database (ARDB) further revealed that aerobic and anaerobic sludge contained various ARGs with high abundance, among which sulfonamide resistance gene sul1 had the highest abundance, occupying over 20% of the total ARGs reads. Tetracycline resistance genes (tet) were highly rich in the anaerobic sludge, among which tet33 had the highest abundance, but was absent in aerobic sludge. Over 70 types of insertion sequences were detected in each sludge sample, and class 1 integrase genes were prevalent in the WWTP. The results highlighted prevalence of ARGs and MGEs in tannery WWTPs, which may deserve more public health concerns.

  5. Diversity, distribution and quantification of antibiotic resistance genes in goat and lamb slaughterhouse surfaces and meat products.

    Science.gov (United States)

    Lavilla Lerma, Leyre; Benomar, Nabil; Knapp, Charles W; Correa Galeote, David; Gálvez, Antonio; Abriouel, Hikmate

    2014-01-01

    The distribution and quantification of tetracycline, sulfonamide and beta-lactam resistance genes were assessed in slaughterhouse zones throughout meat chain production and the meat products; this study represents the first to report quantitatively monitor antibiotic resistance genes (ARG) in goat and lamb slaughterhouse using a culture independent approach, since most studies focused on individual bacterial species and their specific resistance types. Quantitative PCR (qPCR) revealed a high prevalence of tetracycline resistance genes tetA and tetB in almost all slaughterhouse zones. Sulfonamide resistance genes were largely distributed, while beta-lactam resistance genes were less predominant. Statistical analysis revealed that resistant bacteria, in most cases, were spread by the same route in almost all slaughterhouse zones, except for tetB, blaCTX and blaTEM genes, which occurred in few zones as isolated 'hot spots.' The sum of all analyzed ARG indicated that slaughterhouse surfaces and end products act as reservoirs of ARG, mainly tet genes, which were more prevalent in slaughtering room (SR), cutting room (CR) and commercial meat products (MP). Resistance gene patterns suggest they were disseminated throughout slaughterhouse zones being also detected in commercial meat products, with significant correlations between different sampling zones/end products and total resistance in SR, CR and white room (WR) zones, and also refrigerator 4 (F4) and MP were observed. Strategically controlling key zones in slaughterhouse (SR, CR and WR) by adequate disinfection methods could strategically reduce the risks of ARG transmission and minimize the issues of food safety and environment contamination.

  6. Diversity, distribution and quantification of antibiotic resistance genes in goat and lamb slaughterhouse surfaces and meat products.

    Directory of Open Access Journals (Sweden)

    Leyre Lavilla Lerma

    Full Text Available The distribution and quantification of tetracycline, sulfonamide and beta-lactam resistance genes were assessed in slaughterhouse zones throughout meat chain production and the meat products; this study represents the first to report quantitatively monitor antibiotic resistance genes (ARG in goat and lamb slaughterhouse using a culture independent approach, since most studies focused on individual bacterial species and their specific resistance types. Quantitative PCR (qPCR revealed a high prevalence of tetracycline resistance genes tetA and tetB in almost all slaughterhouse zones. Sulfonamide resistance genes were largely distributed, while beta-lactam resistance genes were less predominant. Statistical analysis revealed that resistant bacteria, in most cases, were spread by the same route in almost all slaughterhouse zones, except for tetB, blaCTX and blaTEM genes, which occurred in few zones as isolated 'hot spots.' The sum of all analyzed ARG indicated that slaughterhouse surfaces and end products act as reservoirs of ARG, mainly tet genes, which were more prevalent in slaughtering room (SR, cutting room (CR and commercial meat products (MP. Resistance gene patterns suggest they were disseminated throughout slaughterhouse zones being also detected in commercial meat products, with significant correlations between different sampling zones/end products and total resistance in SR, CR and white room (WR zones, and also refrigerator 4 (F4 and MP were observed. Strategically controlling key zones in slaughterhouse (SR, CR and WR by adequate disinfection methods could strategically reduce the risks of ARG transmission and minimize the issues of food safety and environment contamination.

  7. Diversity, Distribution and Quantification of Antibiotic Resistance Genes in Goat and Lamb Slaughterhouse Surfaces and Meat Products

    Science.gov (United States)

    Lavilla Lerma, Leyre; Benomar, Nabil; Knapp, Charles W.; Correa Galeote, David; Gálvez, Antonio; Abriouel, Hikmate

    2014-01-01

    The distribution and quantification of tetracycline, sulfonamide and beta-lactam resistance genes were assessed in slaughterhouse zones throughout meat chain production and the meat products; this study represents the first to report quantitatively monitor antibiotic resistance genes (ARG) in goat and lamb slaughterhouse using a culture independent approach, since most studies focused on individual bacterial species and their specific resistance types. Quantitative PCR (qPCR) revealed a high prevalence of tetracycline resistance genes tetA and tetB in almost all slaughterhouse zones. Sulfonamide resistance genes were largely distributed, while beta-lactam resistance genes were less predominant. Statistical analysis revealed that resistant bacteria, in most cases, were spread by the same route in almost all slaughterhouse zones, except for tetB, blaCTX and blaTEM genes, which occurred in few zones as isolated ‘hot spots.’ The sum of all analyzed ARG indicated that slaughterhouse surfaces and end products act as reservoirs of ARG, mainly tet genes, which were more prevalent in slaughtering room (SR), cutting room (CR) and commercial meat products (MP). Resistance gene patterns suggest they were disseminated throughout slaughterhouse zones being also detected in commercial meat products, with significant correlations between different sampling zones/end products and total resistance in SR, CR and white room (WR) zones, and also refrigerator 4 (F4) and MP were observed. Strategically controlling key zones in slaughterhouse (SR, CR and WR) by adequate disinfection methods could strategically reduce the risks of ARG transmission and minimize the issues of food safety and environment contamination. PMID:25479100

  8. Tetracycline and Pregnancy

    Science.gov (United States)

    ... teeth. JAMA. 188:178. Kutscher, et al. 1966. Discoloration of deciduous teeth induced by administration of tetracycline antepartum. Am J ... Liss. Vennila V, et al. 2014. Tetracycline-induced discoloration of deciduous teeth: case series. J Int Oral Health 6(3): ...

  9. Bacteriophages Isolated from Chicken Meat and the Horizontal Transfer of Antimicrobial Resistance Genes.

    Science.gov (United States)

    Shousha, Amira; Awaiwanont, Nattakarn; Sofka, Dmitrij; Smulders, Frans J M; Paulsen, Peter; Szostak, Michael P; Humphrey, Tom; Hilbert, Friederike

    2015-07-01

    Antimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested into Escherichia coli ATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P = 0.01) relationship between the presence of phages transducing kanamycin resistance and E. coli isolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance to E. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed in E. coli isolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  10. Dynamics of antibiotic resistance genes and their relationships with system treatment efficiency in a horizontal subsurface flow constructed wetland.

    Science.gov (United States)

    Nõlvak, Hiie; Truu, Marika; Tiirik, Kertu; Oopkaup, Kristjan; Sildvee, Teele; Kaasik, Ants; Mander, Ülo; Truu, Jaak

    2013-09-01

    Municipal wastewater treatment is one of the pathways by which antibiotic resistance genes from anthropogenic sources are introduced into natural ecosystems. This study examined the abundance and proportion dynamics of seven antibiotic resistance genes in the wetland media biofilm and in the influent and effluent of parallel horizontal subsurface flow mesocosm cells of a newly established hybrid constructed wetland treating municipal wastewater. The targeted genes (tetA, tetB, tetM, ermB, sul1, ampC, and qnrS) encode resistance to major antibiotic classes such as tetracyclines, macrolides, sulfonamides, penicillins, and fluoroquinolones, respectively. All targeted antibiotic resistance genes were detectable in the tested mesocosm environments, with the tetA, sul1, and qnrS genes being the most abundant in the mesocosm effluents. After initial fluctuation in the microbial community, target gene abundances and proportions stabilized in the wetland media biofilm. The abundance of 16S rRNA and antibiotic resistance genes, and the proportion of antibiotic resistance genes in the microbial community, were reduced during the wastewater treatment by the constructed wetland. The concentration of antibiotic resistance genes in the system effluent was similar to conventional wastewater treatment facilities; however, the mesocosms reduced sulfonamide resistance encoding sul1 concentrations more effectively than some traditional wastewater treatment options. The concentrations of antibiotic resistance genes in the wetland media biofilm and in effluent were affected by system operation parameters, especially time and temperature. The results also revealed a relationship between antibiotic resistance genes abundance and the removal efficiencies of NO2-N, NH4-N, and organic matter. Correlation analysis between the abundance of individual antibiotic resistance genes in the mesocosms influent, effluent and wetland media biofilm indicated that depending on antibiotic resistance gene

  11. Development of a DNA microarray to detect antimicrobial resistance genes identified in the National Center for Biotechnology Information database.

    Science.gov (United States)

    Frye, Jonathan G; Lindsey, Rebecca L; Rondeau, Gaelle; Porwollik, Steffen; Long, Fred; McClelland, Michael; Jackson, Charlene R; Englen, Mark D; Meinersmann, Richard J; Berrang, Mark E; Davis, Johnnie A; Barrett, John B; Turpin, Jennifer B; Thitaram, Sutawee N; Fedorka-Cray, Paula J

    2010-03-01

    To understand the mechanisms and epidemiology of antimicrobial resistance (AR), the genetic elements responsible must be identified. Due to the myriad of possible genes, a high-density genotyping technique is needed for initial screening. To achieve this, AR genes in the National Center for Biotechnology Information GenBank database were identified by their annotations and compiled into a nonredundant list of 775 genes. A DNA microarray was constructed of 70mer oligonucelotide probes designed to detect these genes encoding resistances to aminoglycosides, beta-lactams, chloramphenicols, glycopeptides, heavy metals, lincosamides, macrolides, metronidazoles, polyketides, quaternary ammonium compounds, streptogramins, sulfonamides, tetracyclines, and trimethoprims as well as resistance transfer genes. The microarray was validated with two fully sequenced control strains of Salmonella enterica: Typhimurium LT2 (sensitive) and Typhi CT18 (multidrug resistance [MDR]). All resistance genes encoded on the MDR plasmid, pHCM1, harbored by CT18 were detected in that strain, whereas no resistance genes were detected in LT2. The microarray was also tested with a variety of bacteria, including MDR Salmonella enterica serovars, Escherichia coli, Campylobacter spp., Enterococcus spp., methicillin-resistant Staphylococcus aureus, Listeria spp., and Clostridium difficile. The results presented here demonstrate that a microarray can be designed to detect virtually all AR genes found in the National Center for Biotechnology Information database, thus reducing the subsequent assays necessary to identify specific resistance gene alleles.

  12. Antimicrobial resistance and resistance genes in Salmonella strains isolated from broiler chickens along the slaughtering process in China.

    Science.gov (United States)

    Zhu, Yuanting; Lai, Haimei; Zou, Likou; Yin, Sheng; Wang, Chengtao; Han, Xinfeng; Xia, Xiaolong; Hu, Kaidi; He, Li; Zhou, Kang; Chen, Shujuan; Ao, Xiaolin; Liu, Shuliang

    2017-10-16

    A total of 189 Salmonella isolates were recovered from 627 samples which were collected from cecal contents of broilers, chicken carcasses, chicken meat after cutting step and frozen broiler chicken products along the slaughtering process at a slaughterhouse in Sichuan province of China. The Salmonella isolates were subjected to antimicrobial susceptibility testing to 10 categories of antimicrobial agents using the Kirby-Bauer disk diffusion method. Those antibiotics-resistant isolates were further investigated for the occurrence of resistance genes, the presence of class 1 integron as well as the associated gene cassettes, and the mutations within the gyrA and parC genes. Consequently, the prevalence of Salmonella was 30.14% (47.96% for cecal content, 18.78% for chicken carcasses, 31.33% for cutting meat and 14.00% for frozen meat, respectively). The predominant serotypes were S. Typhimurium (15.34%) and S. Enteritidis (69.84%). High resistance rates to the following drugs were observed: nalidixic acid (99.5%), ampicillin (87.8%), tetracycline (51.9%), ciprofloxacin (48.7%), trimethoprim/sulfamethoxazole (48.1%), and spectinomycin (34.4%). Antimicrobial resistance profiling showed that 60.8% of isolates were multidrug resistant (MDR), and MDR strains increased from 44.7% to 78.6% along the slaughtering line. 94.6% (n=157) of beta-lactam-resistant isolates harbored at least one resistance gene of bla TEM or bla CTX-M . The relatively low prevalence of aminoglycoside resistance genes (aac(3)-II, aac(3)-IV, and ant(2″)-I) was found in 49 (66.2%) of antibiotic-resistant isolates. The tetracycline resistance genes (tet(A), tet(B), tet(C), and tet(G) and sulfonamide resistance genes (sul1, sul2, and sul3) were identified in 84 (85.7%) and 89 (97.8%) antibiotic-resistant isolates respectively. floR was identified in 44 (97.8%) florfenicol-resistant isolates. Class 1 integron was detected in 37.4% (n=43) of the MDR isolates. Two different gene cassettes, bla OXA-30 -aad

  13. Complete sequence of a plasmid from a bovine methicillin-resistant Staphylococcus aureus harbouring a novel ica-like gene cluster in addition to antimicrobial and heavy metal resistance genes.

    Science.gov (United States)

    Feßler, Andrea T; Zhao, Qin; Schoenfelder, Sonja; Kadlec, Kristina; Brenner Michael, Geovana; Wang, Yang; Ziebuhr, Wilma; Shen, Jianzhong; Schwarz, Stefan

    2017-02-01

    The multiresistance plasmid pAFS11, obtained from a bovine methicillin-resistant Staphylococcus aureus (MRSA) isolate, was completely sequenced and analysed for its structure and organisation. Moreover, the susceptibility to the heavy metals cadmium and copper was determined by broth macrodilution. The 49,189-bp plasmid harboured the apramycin resistance gene apmA, two copies of the macrolide/lincosamide/streptogramin B resistance gene erm(B) (both located on remnants of a truncated transposon Tn917), the kanamycin/neomycin resistance gene aadD, the tetracycline resistance gene tet(L) and the trimethoprim resistance gene dfrK. The latter three genes were part of a 7,284-bp segment which was bracketed by two copies of IS431. In addition, the cadmium resistance operon cadDX as well as the copper resistance genes copA and mco were located on the plasmid and mediated a reduced susceptibility to cadmium and copper. Moreover, a complete novel ica-like gene cluster of so far unknown genetic origin was detected on this plasmid. The ica-like gene cluster comprised four different genes whose products showed 64.4-76.9% homology to the Ica proteins known to be involved in biofilm formation of the S. aureus strains Mu50, Mu3 and N315. However, 96.2-99.4% homology was seen to proteins from S. sciuri NS1 indicating an S. sciuri origin. The finding of five different antibiotic resistance genes co-located on a plasmid with heavy metal resistance genes and an ica-like gene cluster is alarming. With the acquisition of this plasmid, antimicrobial multiresistance, heavy metal resistances and potential virulence properties may be co-selected and spread via a single horizontal gene transfer event. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Comparison of antimicrobial resistance phenotypes and resistance genes in Enterococcus faecalis and Enterococcus faecium from humans in the community, broilers and pigs in Denmark

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Agersø, Yvonne; Gerner-Smidt, P.

    2000-01-01

    Enterococcus faecalis and E. faecium isolated from humans in the community (98 and 65 isolates), broilers (126 and 122), and pigs (102 and 88) during 1998 were tested for susceptibility to 12 different antimicrobial agents and for the presence of selected genes encoding resistance using PCR....... Furthermore, the presence of vancomycin resistant enterococci was examined in 38 human stool samples using selective enrichment. Widespread resistance to chloramphenicol, macrolides, kanamycin, streptomycin, and tetracycline was found among isolates from all three sources. All E. faecium isolates from humans...... and pigs were susceptible to avilamycin, whereas 35% of isolates from broilers were resistant. All E. faecium isolates from humans were susceptible to vancomycin, whereas 10% and 17% of isolates from broilers and pigs, respectively, were resistant. A vancomycin resistant E. faecium isolate was found in one...

  15. Contemporary tetracycline susceptibility testing: doxycycline MIC methods and interpretive criteria (CLSI and EUCAST) performance when testing Gram-positive pathogens.

    Science.gov (United States)

    Jones, Ronald N; Stilwell, Matthew G; Wilson, Michael L; Mendes, Rodrigo E

    2013-05-01

    International susceptibility testing breakpoint organizations and regulatory agencies have markedly differing interpretive criteria for the tetracycline class. Here we examined the magnitude of these differences for doxycycline and tetracycline hydrochloride (HCL) when tested against a collection of 13,176 Gram-positive cocci from a worldwide surveillance network (SENTRY Antimicrobial Surveillance Program, 2010). Clinical and Laboratory Standards Institute (CLSI) breakpoints are routinely higher, usually 4-fold, compared to those of the European Committee on Antimicrobial Susceptibility Testing (EUCAST); however, CLSI recently (2013) modified Streptococcus pneumoniae breakpoints (≤ 2 μg/mL in 2012) to ≤ 0.25 and ≤ 1 μg/mL for doxycycline and tetracycline HCL, respectively. We report that these changes are a promising step toward international breakpoint harmonization, but lack a comprehensive approach needed for testing tetracyclines against all Gram-positive cocci. Generally, EUCAST breakpoint criteria showed i) lower spectrums (reduced susceptibility rates) for the tetracyclines, but highest for doxycycline versus all species examined; ii) greater test accuracy (lower predictive categorical errors), especially for tetracycline to predict doxycycline susceptibility (99.91%); and iii) zone diameter correlate breakpoints which are generally available online. Molecular tests for tet resistance genes demonstrate that tet (K) and tet (M) containing strains can occur in the susceptible population of MIC results by both CLSI and EUCAST breakpoint criteria. In summary, doxycycline continues to show greater comparative potency versus tetracycline HCL against all monitored Gram-positive species and the international harmonization of tetracycline breakpoints should be a priority, as the most recent CLSI update only addressed 1 streptococcal species and 2 tetracycline agents. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Antibiotic Susceptibility Profiles of Dairy Leuconostoc, Analysis of the Genetic Basis of Atypical Resistances and Transfer of Genes In Vitro and in a Food Matrix

    Science.gov (United States)

    Delgado, Susana; Alegría, Ángel; Salvetti, Elisa; Felis, Giovanna E.; Mayo, Baltasar; Torriani, Sandra

    2016-01-01

    In spite of a global concern on the transfer of antibiotic resistances (AR) via the food chain, limited information exists on this issue in species of Leuconostoc and Weissella, adjunct cultures used as aroma producers in fermented foods. In this work, the minimum inhibitory concentration was determined for 16 antibiotics in 34 strains of dairy origin, belonging to Leuconostoc mesenteroides (18), Leuconostoc citreum (11), Leuconostoc lactis (2), Weissella hellenica (2), and Leuconostoc carnosum (1). Atypical resistances were found for kanamycin (17 strains), tetracycline and chloramphenicol (two strains each), and erythromycin, clindamycin, virginiamycin, ciprofloxacin, and rifampicin (one strain each). Surprisingly, L. mesenteroides subsp. mesenteroides LbE16, showed resistance to four antibiotics, kanamycin, streptomycin, tetracycline and virginiamycin. PCR analysis identified tet(S) as responsible for tetracycline resistance in LbE16, but no gene was detected in a second tetracycline-resistant strain, L. mesenteroides subsp. cremoris LbT16. In Leuconostoc mesenteroides subsp. dextranicum LbE15, erythromycin and clindamycin resistant, an erm(B) gene was amplified. Hybridization experiments proved erm(B) and tet(S) to be associated to a plasmid of ≈35 kbp and to the chromosome of LbE15 and LbE16, respectively. The complete genome sequence of LbE15 and LbE16 was used to get further insights on the makeup and genetic organization of AR genes. Genome analysis confirmed the presence and location of erm(B) and tet(S), but genes providing tetracycline resistance in LbT16 were again not identified. In the genome of the multi-resistant strain LbE16, genes that might be involved in aminoglycoside (aadE, aphA-3, sat4) and virginiamycin [vat(E)] resistance were further found. The erm(B) gene but not tet(S) was transferred from Leuconostoc to Enterococcus faecalis both under laboratory conditions and in cheese. This study contributes to the characterization of AR in the

  17. Expression of Bacillus thuringiensis delta-endotoxin genes during vegetative growth.

    OpenAIRE

    Mettus, A M; Macaluso, A

    1990-01-01

    Bacillus thuringiensis delta-endotoxin (crystal protein) genes are normally expressed only during sporulation. It is possible to produce crystal protein during vegetative growth by placing B. thuringiensis crystal protein genes downstream of a strong vegetative promoter. By removing a possible transcriptional terminator of the tetracycline resistance gene of pBC16 and inserting a multiple cloning site, delta-endotoxin genes can be cloned downstream from the tetracycline resistance gene promot...

  18. Retail ready-to-eat food as a potential vehicle for Staphylococcus spp. harboring antibiotic resistance genes.

    Science.gov (United States)

    Chajęcka-Wierzchowska, Wioleta; Zadernowska, Anna; Nalepa, Beata; Sierpińska, Magda; Laniewska-Trokenheim, Lucja

    2014-06-01

    Ready-to-eat (RTE) food, which does not need thermal processing before consumption, could be a vehicle for the spread of antibiotic-resistant microorganisms. As part of general microbiological safety checks, staphylococci are routinely enumerated in these kinds of foods. However, the presence of antibiotic-resistant staphylococci in RTE food is not routinely investigated, and data are only available from a small number of studies. The present study evaluated the pheno- and genotypical antimicrobial resistance profile of Staphylococcus spp. isolated from 858 RTE foods (cheeses, cured meats, sausages, smoked fishes, salads). Of 113 strains isolated, S. aureus was the most prevalent species, followed by S. xylosus, S. saprophyticus, and S. epidermidis. More than half (54.9%) of the isolates were resistant to at least one class of tested antibiotic; of these, 35.4% of the strains were classified as multidrug resistant. Most of the isolates were resistant to cefoxitin (49.6%), followed by clindamycin (39.3%), tigecycline (27.4%), quinupristin-dalfopristin (22.2%), rifampin (20.5%), tetracycline (17.9%), and erythromycin (8.5%). All methicillin-resistant staphylococci harbored the mecA gene. Among the isolates resistant to at least one antibiotic, 38 harbored tetracycline resistance determinant tet (M), 24 harbored tet (L), and 9 harbored tet (K). Of the isolates positive for tet (M) genes, 34.2% were positive for the Tn916-Tn1545-like integrase family gene. Our results indicated that retail RTE food could be considered an important route for the transmission of antibiotic-resistant bacteria harboring multiple antibiotic resistance genes.

  19. Antibiotic susceptibility/resistant gene profiles of Group B streptococci isolates from pregnant women in a tertiary institution in Nigeria

    Directory of Open Access Journals (Sweden)

    Charles J Elikwu

    2016-01-01

    Full Text Available Background: Penicillin is recommended as the first-line agent for intrapartum antibiotic prophylaxis (IAP. Although Group B Streptococcus (GBS strains are generally susceptible to penicillin with only occasional resistance, they show varying resistance to erythromycin, clindamycin, and tetracycline. Therefore, knowledge of the resistance profile of GBS in the local environment will be useful for administration of appropriate intrapartum antibiotics prophylaxis. Methodology: Rectovaginal swabs collected from pregnant women were cultured for GBS using conventional media. Kirby-Bauer disc diffusion method was performed according to the Clinical and Laboratory Standards Institute guidelines on GBS isolates to determine the antibiotic susceptibility patterns of the isolates. Inducible clindamycin resistance was detected by using the D-zone test. Resistance determinants genes were discerned with conventional polymerase chain reaction. Results: Carriage rates of GBS among pregnant women studied were 19.7%. GBS colonizing the pregnant mothers were uniformly susceptible (100% to penicillin, vancomycin, and ceftriaxone. Only three (6.5% of the isolates showed inducible clindamycin resistance. ermA gene was present in all three GBS isolates with inducible macrolide-lincosamide-streptogramin resistance. ermB was absent in all the strains tested. mefA/E gene was carried by two of the macrolide-clindamycin resistance isolates. tetM gene was carried by all isolates with tetracycline resistance phenotypes. Conclusion: In this study, all GBS isolates were susceptible to penicillin G, the recommended antibiotic for IAP. The presence of resistance to erythromycin and inducible resistance to clindamycin excludes the use of these agents as alternatives in cases of penicillin allergy. In this case, vancomycin is the drug of choice as recommended in the updated Centers for Disease Control guideline.

  20. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes.

    Science.gov (United States)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang; Zhang, Zhijian

    2015-11-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P biofertilizer in agroecosystems. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  1. Detection of sulfonamide resistant bacteria and resistance genes in soils

    Science.gov (United States)

    Wu, Nan; Zhang, Weiyu; Liu, Huifen; Wang, Xiaobo; Yang, Fan; Zeng, Ming; Chen, Pinpin; Wang, Xiao

    2017-04-01

    Manure application could accelerate the environmental dissemination of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in soils. In this study, the prevalence of sulfonamide resistant bacteria and resistance genes was investigated in agricultural soils to which organic manures had been applied in Tianjin, China. Anti-sulfonamide bacteria were found in the range of 3.29 × 104 to 1.70 × 105 CFU/g dry soil, occupying 1.5% to 2.2% of total viable counts. And sulI and sulII genes were detected in all sampling sites, with relative abundances of 5.69 × 10-5 to 6.95 × 10-4 and 4.28 × 10-4 to 1.25 × 10-3 respectively. No significant correlations between cultivable sulfonamide resistant bacteria and sul genes were found in this study. While sulI showed significant positive correlation with soil organic matter. Overall, the results highlight that soil plays an important role in resistance genes capture as the environmental reservoir.

  2. Tetracycline susceptibility of the ingested Lactobacillus acidophilus LaCH-5 and Bifidobacterium animalis subsp. lactis Bb-12 strains during antibiotic/probiotic intervention.

    Science.gov (United States)

    Saarela, Maria; Maukonen, Johanna; von Wright, Atte; Vilpponen-Salmela, Terttu; Patterson, Andrea J; Scott, Karen P; Hämynen, Heikki; Mättö, Jaana

    2007-03-01

    We investigated the effects of oral therapy with doxycycline, a tetracycline group antibiotic, on the gastrointestinal (GI) survival and tetracycline susceptibility of probiotic strains Lactobacillus acidophilus LaCH-5 and Bifidobacterium animalis subsp. lactis Bb-12. In addition, the influence of doxycycline therapy on the diversity of the predominant faecal microbiota was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Faecal samples from the antibiotic group (receiving antibiotics and probiotics) and the control group (receiving probiotics only) were analysed for anaerobically and aerobically growing bacteria, bifidobacteria and lactic acid bacteria as well as for the dominant microbiota. Although doxycycline consumption did not have a large impact on GI survival of the probiotics, it had a detrimental effect on the bifidobacteria and on the diversity of the dominant faecal microbiota. A higher proportion of tetracycline-resistant anaerobically growing bacteria and bifidobacteria was detected in the antibiotic group than in the control group. Several antibiotic group subjects had faecal B. animalis subsp. lactis Bb-12-like isolates with reduced tetracycline susceptibility. This was unlikely to be due to the acquisition of novel tetracycline resistance determinants, since only tet(W), which is also present in the ingested B. animalis subsp. lactis Bb-12, was found in the resistant isolates. Thus, concomitant ingestion of probiotic L. acidophilus LaCH-5 and B. animalis subsp. lactis Bb-12 with the antibiotic did not generate a safety risk regarding the possible GI transfer of tetracycline resistance genes to the ingested strains.

  3. Antimicrobial resistance and antimicrobial resistance genes in marine bacteria from salmon aquaculture and non-aquaculture sites.

    Science.gov (United States)

    Shah, Syed Q A; Cabello, Felipe C; L'abée-Lund, Trine M; Tomova, Alexandra; Godfrey, Henry P; Buschmann, Alejandro H; Sørum, Henning

    2014-05-01

    Antimicrobial resistance (AR) detected by disc diffusion and antimicrobial resistance genes detected by DNA hybridization and polymerase chain reaction with amplicon sequencing were studied in 124 marine bacterial isolates from a Chilean salmon aquaculture site and 76 from a site without aquaculture 8 km distant. Resistance to one or more antimicrobials was present in 81% of the isolates regardless of site. Resistance to tetracycline was most commonly encoded by tetA and tetG; to trimethoprim, by dfrA1, dfrA5 and dfrA12; to sulfamethizole, by sul1 and sul2; to amoxicillin, by blaTEM ; and to streptomycin, by strA-strB. Integron integrase intl1 was detected in 14 sul1-positive isolates, associated with aad9 gene cassettes in two from the aquaculture site. intl2 Integrase was only detected in three dfrA1-positive isolates from the aquaculture site and was not associated with gene cassettes in any. Of nine isolates tested for conjugation, two from the aquaculture site transferred AR determinants to Escherichia coli. High levels of AR in marine sediments from aquaculture and non-aquaculture sites suggest that dispersion of the large amounts of antimicrobials used in Chilean salmon aquaculture has created selective pressure in areas of the marine environment far removed from the initial site of use of these agents. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Identification of acquired antimicrobial resistance genes

    DEFF Research Database (Denmark)

    Zankari, Ea; Hasman, Henrik; Cosentino, Salvatore

    2012-01-01

    -novo-sequenced isolates.ResultsWhen testing the 1862 GenBank files, the method identified the resistance genes with an ID = 100% (100% identity) to the genes in ResFinder. Agreement between in silico predictions and phenotypic testing was found when the method was further tested on 23 isolates of five different bacterial......ObjectivesIdentification of antimicrobial resistance genes is important for understanding the underlying mechanisms and the epidemiology of antimicrobial resistance. As the costs of whole-genome sequencing (WGS) continue to decline, it becomes increasingly available in routine diagnostic...... laboratories and is anticipated to substitute traditional methods for resistance gene identification. Thus, the current challenge is to extract the relevant information from the large amount of generated data.MethodsWe developed a web-based method, ResFinder that uses BLAST for identification of acquired...

  5. Prevalence of antibiotic resistance genes from effluent of coastal aquaculture, South Korea.

    Science.gov (United States)

    Jang, Hyun Min; Kim, Young Beom; Choi, Sangki; Lee, Yunho; Shin, Seung Gu; Unno, Tatsuya; Kim, Young Mo

    2018-02-01

    The wide use of antibiotics in aquaculture for prophylactic and therapeutic purposes can potentially lead to the prevalence of antibiotic resistance genes (ARGs). This study reports for the first time the profile of ARGs from effluents of coastal aquaculture located in South Jeolla province and Jeju Island, South Korea. Using quantitative PCR (qPCR), twenty-two ARGs encoding tetracycline resistance (tetA, tetB, tetD, tetE, tetG, tetH, tetM, tetQ, tetX, tetZ, tetBP), sulfonamide resistance (sul1, sul2), quinolone resistance (qnrD, qnrS, aac(6')-Ib-cr), β-lactams resistance (bla TEM , bla CTX , bla SHV ), macrolide resistance (ermC), florfenicol resistance (floR) and multidrug resistance (oqxA) and a class 1 integrons-integrase gene (intI1) were quantified. In addition, Illumina Miseq sequencing was applied to investigate microbial community differences across fish farm effluents. Results from qPCR showed that the total number of detected ARGs ranged from 4.24 × 10 -3 to 1.46 × 10 -2 copies/16S rRNA gene. Among them, tetB and tetD were predominant, accounting for 74.8%-98.0% of the total ARGs. Furthermore, intI1 gene showed positive correlation with tetB, tetD, tetE, tetH, tetX, tetZ tetQ and sul1. Microbial community analysis revealed potential host bacteria for ARGs and intI1. Two genera, Vibrio and Marinomonas belonging to Gammaproteobacteria, showed significant correlation with tetB and tetD, the most dominant ARGs in all samples. Also, operational taxonomic units (OTUs)-based network analysis revealed that ten OTUs, classified into the phyla Proteobacteria, Cyanobacteria/Chloroplast, Bacteroidetes, Verrucomicrobia and an unclassified phylum, were potential hosts of tetracycline resistance genes (i.e., tetA, tetG, tetH, tetM, tetQ and tetZ). Further systematic monitoring of ARGs is warranted for risk assessment and management of antibacterial resistance from fish farm effluents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Antimicrobial susceptibility and antibiotic resistance gene transfer analysis of foodborne, clinical, and environmental Listeria spp. isolates including Listeria monocytogenes.

    Science.gov (United States)

    Bertsch, David; Muelli, Mirjam; Weller, Monika; Uruty, Anaïs; Lacroix, Christophe; Meile, Leo

    2014-02-01

    The aims of this study were to assess antibiotic resistance pheno- and genotypes in foodborne, clinical, and environmental Listeria isolates, as well as to elucidate the horizontal gene transfer potential of detected resistance genes. A small fraction of in total 524 Listeria spp. isolates (3.1%) displayed acquired antibiotic resistance mainly to tetracycline (n = 11), but also to clindamycin (n = 4) and trimethoprim (n = 3), which was genotypically confirmed. In two cases, a tetracycline resistance phenotype was observed together with a trimethoprim resistance phenotype, namely in a clinical L. monocytogenes strain and in a foodborne L. innocua isolate. Depending on the applied guidelines, a differing number of isolates (n = 2 or n = 20) showed values for ampicillin that are on the edge between intermediate susceptibility and resistance. Transferability of the antibiotic resistance genes from the Listeria donors, elucidated in vitro by filter matings, was demonstrated for genes located on transposons of the Tn916 family and for an unknown clindamycin resistance determinant. Transfer rates of up to 10(-5) transconjugants per donor were obtained with a L. monocytogenes recipient and up to 10(-7) with an Enterococcus faecalis recipient, respectively. Although the prevalence of acquired antibiotic resistance in Listeria isolates from this study was rather low, the transferability of these resistances enables further spread in the future. This endorses the importance of surveillance of L. monocytogenes and other Listeria spp. in terms of antibiotic susceptibility. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  7. Excretion of antibiotic resistance genes by dairy calves fed milk replacers with varying doses of antibiotics

    Directory of Open Access Journals (Sweden)

    Callie H. Thames

    2012-04-01

    Full Text Available Elevated levels of antibiotic resistance genes (ARGs in soil and water have been linked to livestock farms and in some cases feed antibiotics may select for antibiotic resistant gut microbiota. The purpose of this study was to examine the establishment of ARGs in the feces of calves receiving milk replacer containing no antibiotics versus subtherapeutic or therapeutic doses of tetracycline and neomycin. The effect of antibiotics on calf health was also of interest. Twenty-eight male and female dairy calves were assigned to one of the three antibiotic treatment groups at birth and fecal samples were collected at weeks 6, 7 (prior to weaning, and 12 (5 weeks after weaning. ARGs corresponding to the tetracycline (tetC, tetG, tetO, tetW, and tetX, macrolide (ermB, ermF, and sulfonamide (sul1, sul2 classes of antibiotics along with the class I integron gene, intI1, were monitored by quantitative polymerase chain reaction as potential indicators of direct selection, co-selection, or horizontal gene transfer of ARGs. Surprisingly, there was no significant effect of antibiotic treatment on the absolute abundance (gene copies/ g wet manure of any of the ARGs except ermF, which was lower in the antibiotic-treated calf manure, presumably because a significant portion of host bacterial cells carrying ermF were not resistant to tetracycline or neomycin. However, relative abundance (gene copies normalized to 16S rRNA genes of tetO was higher in calves fed the highest dose of antibiotic than in the other treatments. All genes, except tetC and intI1, were detectable in feces from 6 weeks onwards, and tetW and tetG significantly increased (P<0.10, even in control calves. Overall, the results provide new insight into the colonization of calf gut flora with ARGs in the early weeks. Although feed antibiotics exerted little effect on the ARGs monitored in this study, the fact that they also provided no health benefit suggests that the greater than conventional

  8. Biofilm-Forming ClinicalStaphylococcusIsolates Harbor Horizontal Transfer and Antibiotic Resistance Genes.

    Science.gov (United States)

    Águila-Arcos, Sandra; Álvarez-Rodríguez, Itxaso; Garaiyurrebaso, Olatz; Garbisu, Carlos; Grohmann, Elisabeth; Alkorta, Itziar

    2017-01-01

    Infections caused by staphylococci represent a medical concern, especially when related to biofilms located in implanted medical devices, such as prostheses and catheters. Unfortunately, their frequent resistance to high doses of antibiotics makes the treatment of these infections a difficult task. Moreover, biofilms represent a hot spot for horizontal gene transfer (HGT) by bacterial conjugation. In this work, 25 biofilm-forming clinical staphylococcal isolates were studied. We found that Staphylococcus epidermidis isolates showed a higher biofilm-forming capacity than Staphylococcus aureus isolates. Additionally, horizontal transfer and relaxase genes of two common staphylococcal plasmids, pSK41 and pT181, were detected in all isolates. In terms of antibiotic resistance genes, aac6-aph2a, ermC , and tetK genes, which confer resistance to gentamicin, erythromycin, and tetracycline, respectively, were the most prevalent. The horizontal transfer and antibiotic resistance genes harbored on these staphylococcal clinical strains isolated from biofilms located in implanted medical devices points to the potential risk of the development and dissemination of multiresistant bacteria.

  9. Detection of antibiotic resistance genes in samples from acute and chronic endodontic infections and after treatment.

    Science.gov (United States)

    Rôças, Isabela N; Siqueira, José F

    2013-09-01

    The purpose of this study was twofold: survey samples from acute and chronic endodontic infections for the presence of genes encoding resistance to beta-lactams, tetracycline and erythromycin, and evaluate the ability of treatment to eliminate these genes from root canals. DNA extracts from samples of abscess aspirates (n=25) and root canals of teeth with asymptomatic apical periodontitis (n=24) were used as template for direct detection of the genes blaTEM, cfxA, tetM, tetQ, tetW, and ermC using real-time polymerase chain reaction (PCR). Bacterial presence was determined using PCR with universal bacterial primers. Root canals of the asymptomatic cases were also sampled and evaluated after chemomechanical procedures using NiTi instruments with 2.5% NaOCl irrigation. All abscess and initial root canal samples were positive for bacteria. At least one of the target resistance genes was found in 36% of the abscess samples and 67% of the asymptomatic cases. The most prevalent genes in abscesses were blaTEM (24%) and ermC (24%), while tetM (42%) and tetW (29%) prevailed in asymptomatic cases. The blaTEM gene was significantly associated with acute cases (p=0.02). Conversely, tetM was significantly more prevalent in asymptomatic cases (p=0.008). Treatment eliminated resistance genes from most cases. Acute and chronic endodontic infections harboured resistance genes for 3 classes of widely used antibiotics. In most cases, treatment was effective in eliminating these genes, but there were a few cases in which they persisted. The implications of persistence are unknown. Direct detection of resistance genes in abscesses may be a potential method for rapid diagnosis and establishment of proactive antimicrobial therapy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Exploring Antibiotic Resistance Genes and Metal Resistance Genes in Plasmid Metagenomes from Wastewater Treatment Plants

    Directory of Open Access Journals (Sweden)

    An-Dong eLi

    2015-09-01

    Full Text Available Plasmids operate as independent genetic elements in microorganism communities. Through horizontal gene transfer, they can provide their host microorganisms with important functions such as antibiotic resistance and heavy metal resistance. In this study, six metagenomic libraries were constructed with plasmid DNA extracted from influent, activated sludge and digested sludge of two wastewater treatment plants. Compared with the metagenomes of the total DNA extracted from the same sectors of the wastewater treatment plant, the plasmid metagenomes had significantly higher annotation rates, indicating that the functional genes on plasmids are commonly shared by those studied microorganisms. Meanwhile, the plasmid metagenomes also encoded many more genes related to defense mechanisms, including ARGs. Searching against an antibiotic resistance genes (ARGs database and a metal resistance genes (MRGs database revealed a broad-spectrum of antibiotic (323 out of a total 618 subtypes and metal resistance genes (23 out of a total 23 types on these plasmid metagenomes. The influent plasmid metagenomes contained many more resistance genes (both ARGs and MRGs than the activated sludge and the digested sludge metagenomes. Sixteen novel plasmids with a complete circular structure that carried these resistance genes were assembled from the plasmid metagenomes. The results of this study demonstrated that the plasmids in wastewater treatment plants could be important reservoirs for resistance genes, and may play a significant role in the horizontal transfer of these genes.

  11. Resistance Genes in Global Crop Breeding Networks.

    Science.gov (United States)

    Garrett, K A; Andersen, K F; Asche, F; Bowden, R L; Forbes, G A; Kulakow, P A; Zhou, B

    2017-10-01

    Resistance genes are a major tool for managing crop diseases. The networks of crop breeders who exchange resistance genes and deploy them in varieties help to determine the global landscape of resistance and epidemics, an important system for maintaining food security. These networks function as a complex adaptive system, with associated strengths and vulnerabilities, and implications for policies to support resistance gene deployment strategies. Extensions of epidemic network analysis can be used to evaluate the multilayer agricultural networks that support and influence crop breeding networks. Here, we evaluate the general structure of crop breeding networks for cassava, potato, rice, and wheat. All four are clustered due to phytosanitary and intellectual property regulations, and linked through CGIAR hubs. Cassava networks primarily include public breeding groups, whereas others are more mixed. These systems must adapt to global change in climate and land use, the emergence of new diseases, and disruptive breeding technologies. Research priorities to support policy include how best to maintain both diversity and redundancy in the roles played by individual crop breeding groups (public versus private and global versus local), and how best to manage connectivity to optimize resistance gene deployment while avoiding risks to the useful life of resistance genes. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

  12. Detection of 140 clinically relevant antibiotic-resistance genes in the plasmid metagenome of wastewater treatment plant bacteria showing reduced susceptibility to selected antibiotics.

    Science.gov (United States)

    Szczepanowski, Rafael; Linke, Burkhard; Krahn, Irene; Gartemann, Karl-Heinz; Gützkow, Tim; Eichler, Wolfgang; Pühler, Alfred; Schlüter, Andreas

    2009-07-01

    To detect plasmid-borne antibiotic-resistance genes in wastewater treatment plant (WWTP) bacteria, 192 resistance-gene-specific PCR primer pairs were designed and synthesized. Subsequent PCR analyses on total plasmid DNA preparations obtained from bacteria of activated sludge or the WWTP's final effluents led to the identification of, respectively, 140 and 123 different resistance-gene-specific amplicons. The genes detected included aminoglycoside, beta-lactam, chloramphenicol, fluoroquinolone, macrolide, rifampicin, tetracycline, trimethoprim and sulfonamide resistance genes as well as multidrug efflux and small multidrug resistance genes. Some of these genes were only recently described from clinical isolates, demonstrating genetic exchange between clinical and WWTP bacteria. Sequencing of selected resistance-gene-specific amplicons confirmed their identity or revealed that the amplicon nucleotide sequence is very similar to a gene closely related to the reference gene used for primer design. These results demonstrate that WWTP bacteria are a reservoir for various resistance genes. Moreover, detection of about 64 % of the 192 reference resistance genes in bacteria obtained from the WWTP's final effluents indicates that these resistance determinants might be further disseminated in habitats downstream of the sewage plant.

  13. Characterisation of novel target promoters for the dexamethasone-inducible/tetracycline-repressible regulator TGV using luciferase and isopentenyl transferase as sensitive reporter genes.

    Science.gov (United States)

    Böhner, S; Gatz, C

    2001-02-01

    The chimeric transcriptional activator TGV mediates dexamethasone (dx)-inducible and tetracycline (tc)-repressible transgene expression in tobacco (dx-on/ tc-off system). The expression profiles of four different synthetic target promoters, comprising multiple TGV binding sites upstream of a core promoter, were characterised using the sensitive luciferase assay. Induction factors of over 1,000 were measured in roots and leaves of over 30% of the transgenic plants, irrespective of the promoter used. Promoters PTF and PTax, which carry the -48 to +1 region of the Cauliflower Mosaic Virus 35S promoter, showed higher expression levels in both the uninduced and induced states than PTop10 and PTFM, which harbour several point mutations in this region. Moreover, PTax expressed higher background activities than PTF, indicating that the sequence of the synthetic regulatory region can influence background levels. The usefulness of the dx-on/tc-off system for experiments addressing gene function was demonstrated by using it to control the expression of isopentenyl transferase. This enzyme catalyses the rate-limiting step in cytokinin biosynthesis and causes phenotypic effects even at low expression levels. Only dx-induced transgenic plants displayed phenotypic alterations indicative for increased cytokinin synthesis (e.g. outgrowth of lateral buds). Simultaneous treatment of selected buds with the antiinducer tc suppressed bud growth. This result suggests that cytokinins cannot serve as mobile signals to elicit the release of apical dominance in tissues compromised for enhanced cytokinin synthesis.

  14. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A.; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang; Zhang, Zhijian; Goodrich-Blair, H.

    2015-08-21

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M),tet(O),tet(Q), andtet(W)] were reduced (P< 0.05), while those of genes encoding sulfonamide resistance (sul1andsul2) were increased (P< 0.05) when normalized to 16S rRNA. The abundances of tetracycline resistance genes were correlated (P< 0.05) with the changing concentrations of tetracyclines in the manure. The overall diversity and richness of the bacteria significantly decreased during vermicomposting, accompanied by a 100 times increase in the relative abundance ofFlavobacteriaceaespp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the familyRuminococcaceae, classBacilli, or phylumProteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to

  15. Enhanced gentamicin killing of Escherichia coli by tet gene expression.

    OpenAIRE

    Merlin, T L; Corvo, D L; Gill, J H; Griffith, J K

    1989-01-01

    Time-kill studies were performed to determine the effect of tetracycline resistance (tet) gene expression on gentamicin killing of Escherichia coli. Expression of tet increased gentamicin killing in laboratory strains and clinical isolates. A role for tetracycline in inducing tet expression and increasing the bactericidal activity of aminoglycosides is suggested.

  16. Occurrence of antibiotics and antibiotic resistance genes in a sewage treatment plant and its effluent-receiving river.

    Science.gov (United States)

    Xu, Jian; Xu, Yan; Wang, Hongmei; Guo, Changsheng; Qiu, Huiyun; He, Yan; Zhang, Yuan; Li, Xiaochen; Meng, Wei

    2015-01-01

    The extensive use of antibiotics has caused the contamination of both antibiotics and antibiotic resistance genes (ARGs) in the environment. In this study, the abundance and distribution of antibiotics and ARGs from a sewage treatment plant (STP) and its effluent-receiving river in Beijing China were characterized. Three classes of antibiotics including tetracycline, sulfonamide and quinolone were quantified by LC-MS/MS. In the secondary effluent they were detected at 195, 2001 and 3866 ng L(-1), respectively, which were higher than in the receiving river water. A total of 13 ARGs (6 tet genes: tetA, tetB, tetE, tetW, tetM and tetZ, 3 sulfonamide genes: sul1, sul2 and sul3, and 4 quinolone genes: gryA, parC, qnrC and qnrD) were determined by quantitative PCR. For all ARGs, sulfonamide resistance genes were present at relatively high concentrations in all samples, with the highest ARG concentration above 10(-1). ARGs remained relatively stable along each sewage treatment process. The abundances of detected ARGs from the STP were also higher than its receiving river. Bivariate correlation analysis showed that relative tet gene copies (tetB/16S-rRNA and tetW/16S-rRNA) were strongly correlated with the concentrations of tetracycline residues (r(2)>0.8, presistance gene (qnrC/16S-rRNA) and the concentrations of enrofloxacin (ENR) was also determined. The difference of ARGs levels in the raw influent and secondary effluent suggested that the STP treatment process may induce to increase the abundance of resistance genes. The results showed that the sewage was an important repository of the resistance genes, which need to be effectively treated before discharge into the natural water body. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Virulence genes, antibiotic resistance and integrons in Escherichia coli strains isolated from synanthropic birds from Spain.

    Science.gov (United States)

    Sacristán, C; Esperón, F; Herrera-León, S; Iglesias, I; Neves, E; Nogal, V; Muñoz, M J; de la Torre, A

    2014-01-01

    The aim of this study was to determine the presence of virulence genes and antibiotic resistance profiles in 164 Escherichia coli strains isolated from birds (feral pigeons, hybrid ducks, house sparrows and spotless starlings) inhabiting urban and rural environments. A total of eight atypical enteropathogenic E. coli strains were identified: one in a house sparrow, four in feral pigeons and three in spotless starlings. Antibiotic resistance was present in 32.9% (54) of E. coli strains. The dominant type of resistance was to tetracycline (21.3%), ampicillin (19.5%) and sulfamethoxazole (18.9%). Five isolates had class 1 integrons containing gene cassettes encoding for dihydrofolate reductase A (dfrA) and aminoglycoside adenyltransferase A (aadA), one in a feral pigeon and four in spotless starlings. To our knowledge, the present study constitutes the first detection of virulence genes from E. coli in spotless starlings and house sparrows, and is also the first identification worldwide of integrons containing antibiotic resistance gene cassettes in E. coli strains from spotless starlings and pigeons.

  18. Genetic characterisation of antimicrobial resistance and virulence genes in Staphylococcus aureus isolated from commercial broiler chickens in the Durban metropolitan area, South Africa

    Directory of Open Access Journals (Sweden)

    Nelisiwe Mkize

    2017-01-01

    Full Text Available Antimicrobial resistance of Staphylococcus aureus in human and veterinary medicine is a serious worldwide problem. The aim of this study was to investigate the prevalence of S. aureus in commercial broiler chickens as well as to establish antimicrobial susceptibility and the distribution of genetic determinants conferring resistance and virulence. One hundred and ninety-four samples were aseptically collected from broiler chicken slaughterhouses and retail outlets around the Durban metropolitan area in South Africa. Microbiological and molecular methods were used to detect the presence of S. aureus as well as its resistance- and virulence-associated genes. Polymerase chain reaction (PCR was used to confirm the presence of S. aureus by amplifying the nuc gene. Approximately 54% of 194 samples were positive for S. aureus. The disc diffusion technique was used to investigate antimicrobial susceptibility profiles of the S. aureus isolates to a battery of 10 antimicrobial agents, namely ampicillin, chloramphenicol, gentamicin, erythromycin, cefoxitin, kanamycin, streptomycin, tetracycline, vancomycin and trimethoprim. The results demonstrated that S. aureus isolates of abattoir origin had a high level (79.4% of resistance to tetracycline, followed by ampicillin, vancomycin, cefoxitin, trimethoprim, erythromycin and streptomycin with resistance rates of 65.1%, 61.9%, 60.3%, 58.7%, 57.1% and 46.0%, respectively. Staphylococcus aureus isolates of retail origin exhibited higher antimicrobial resistance prevalence rates than those of abattoir origin. Tetracycline had the highest resistance rate (100%, followed by cefoxitin (91.7%, erythromycin (83.3%, streptomycin (83.3% and kanamycin (66.7%. All isolates were resistant to two or more antimicrobial agents. Out of the four virulence genes that were screened, only two were detected (coagulase and protein A; however, their prevalence rates were very low. All antimicrobial resistance genes screened were

  19. Photohemolytic potency of tetracyclines

    Energy Technology Data Exchange (ETDEWEB)

    Bjellerup, M.; Ljunggren, B.

    1985-04-01

    Hemolysis induced by long-wave ultraviolet radiation (UVA) and 8 different commercial tetracycline derivatives was studied in a model using human red blood cells. Demethylchlortetracycline and doxycycline were shown to have pronounced hemolytic properties causing 88% and 85% hemolysis, respectively, at a concentration of 50 micrograms/ml and 72 J/ cm2 of UVA. Tetracycline, oxytetracycline, and chlortetracycline caused maximally 18% hemolysis at 200 micrograms/ml and lymecycline only 7% at 100 micrograms/ml. Methacycline showed intermediate hemolytic effect of 36% at 200 micrograms/ml. Minocycline had no hemolytic effect whatsoever. These experimental data correlate very well with clinical reports and comparative phototoxicity trials in humans. Photohemolysis may thus be of value for predicting tetracycline phototoxicity.

  20. Antibiotic Resistance Genetic Markers and Integrons in White Soft Cheese: Aspects of Clinical Resistome and Potentiality of Horizontal Gene Transfer.

    Science.gov (United States)

    de Paula, Ana Caroline L; Medeiros, Julliane D; de Azevedo, Analice C; de Assis Chagas, Jéssica M; da Silva, Vânia L; Diniz, Cláudio G

    2018-02-19

    Antibiotic resistance poses an important threat to global public health and has become a challenge to modern medicine. The occurrence of antibiotic-resistant bacteria in a broad range of foods has led to a growing concern about the impact that food may have as a reservoir of antibiotic resistance genes. Considering Minas Frescal Cheese (MFC)-a typical Brazilian white soft cheese-and its economic and cultural values, in this study, medically relevant antimicrobial-resistance genetic markers (AR genes) were screened, and the occurrence of integrons were evaluated in manufactured MFC using culture-independent approaches. Through a fingerprinting analysis, the tested MFCs were brand-clustered, indicating reproducibility along the production chain. A common core of resistance markers in all brands evaluated and related antimicrobials such as β-lactams, tetracyclines, quinolones, and sulfonamide was detected. Several other markers, including efflux pumps and aminoglycosides-resistance were distributed among brands. Class 1 and 2 integrons were observed, respectively, in 77% and 97% of the samples. The presence of AR genes is of special interest due to their clinical relevance. Taken together, the data may suggest that the production chain of MFC might contribute to the spread of putative drug-resistant bacteria, which could greatly impact human health. Furthermore, detection of class 1 and class 2 integrons in MFC has led to discussions about resistance gene spread in this traditional cheese, providing evidence of potential horizontal transfer of AR genes to human gut microbiota.

  1. Frequency, virulence genes and antimicrobial resistance of Listeria spp. isolated from bovine clinical mastitis.

    Science.gov (United States)

    Jamali, Hossein; Radmehr, Behrad

    2013-11-01

    The aims of this study were to determine the prevalence, characteristics and antimicrobial resistance of Listeria spp. isolated from bovine clinical mastitis in Iran. Listeria spp. were detected in 21/207 bovine mastitic milk samples from dairy farms in Iran, comprising L. monocytogenes (n=17), L. innocua (n=3) and L. ivanovii (n=1). L. monocytogenes isolates were grouped into serogroups '4b, 4d, 4e', '1/2a, 3a', '1/2b, 3b, 7' and '1/2c, 3c'; all harboured inlA, inlC and inlJ virulence genes. Listeria spp. were most frequently resistant to penicillin G (14/21 isolates, 66.7%) and tetracyclines (11/21 isolates, 52.4%). Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Transgene regulation using the tetracycline-inducible TetR-KRAB system after AAV-mediated gene transfer in rodents and nonhuman primates.

    Directory of Open Access Journals (Sweden)

    Caroline Le Guiner

    Full Text Available Numerous studies have demonstrated the efficacy of the Adeno-Associated Virus (AAV-based gene delivery platform in vivo. The control of transgene expression in many protocols is highly desirable for therapeutic applications and/or safety reasons. To date, the tetracycline and the rapamycin dependent regulatory systems have been the most widely evaluated. While the long-term regulation of the transgene has been obtained in rodent models, the translation of these studies to larger animals, especially to nonhuman primates (NHP, has often resulted in an immune response against the recombinant regulator protein involved in transgene expression regulation. These immune responses were dependent on the target tissue and vector delivery route. Here, using AAV vectors, we evaluated a doxycyclin-inducible system in rodents and macaques in which the TetR protein is fused to the human Krüppel associated box (KRAB protein. We demonstrated long term gene regulation efficiency in rodents after subretinal and intramuscular administration of AAV5 and AAV1 vectors, respectively. However, as previously described for other chimeric transactivators, the TetR-KRAB-based system failed to achieve long term regulation in the macaque after intramuscular vector delivery because of the development of an immune response. Thus, immunity against the chimeric transactivator TetR-KRAB emerged as the primary limitation for the clinical translation of the system when targeting the skeletal muscle, as previously described for other regulatory proteins. New developments in the field of chimeric drug-sensitive transactivators with the potential to not trigger the host immune system are still needed.

  3. Trends in antimicrobial susceptibility and presence of resistance genes in Staphylococcus hyicus isolated from exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Jensen, L. B.

    2002-01-01

    (vat, vga, vga(B), vat(B), vat(D) and vat(E)), streptomycin (aadE) and tetracycline resistance (tet(K), tet(L), tet(M) and tet(O)) were determined in selected isolates. The occurrence of erythromycin resistance increased from 33% in 1996 to a maximum of 62% in 1997 and decreased to 26% in 2001...... streptogramin resistance gene in four streptogramin resistant isolates. Of the 55 erythromycin resistant isolates examined, five contained erm(A), 13 erm(B), 35 erm(C) and two both erm(A) and erm(C). The presence of erm(B) was confirmed by hybridization to plasmid profiles in all 13 PCR-positive isolates. Of 52...

  4. Antimicrobial resistance in Salmonella spp. recovered from patients admitted to six different hospitals in Tehran, Iran from 2007 to 2008

    DEFF Research Database (Denmark)

    Tajbakhsh, Mercedeh; Hendriksen, Rene S.; Nochi, Zahra

    2012-01-01

    %) and kanamycin (14%). The tetracycline resistance genes tet(A), tet(B), and tet(G) were found in 28%, 14% and 6% of the tetracycline resistant isolates, respectively. The genes aadA, aadB, strA, strB and aphA1-Iab were present in 83%, 55%, 34%, 1% and 17% of the aminoglycoside resistant isolates, respectively...

  5. Resistance patterns, ESBL genes, and genetic relatedness of Escherichia coli from dogs and owners

    Science.gov (United States)

    Carvalho, A.C.; Barbosa, A.V.; Arais, L.R.; Ribeiro, P.F.; Carneiro, V.C.; Cerqueira, A.M.F.

    2016-01-01

    Antimicrobial resistance in Escherichia coli isolated from pet dogs can be considered a potential threat of infection for the human population. Our objective was to characterize the resistance pattern, extended spectrum beta-lactamase production and genetic relatedness of multiresistant E. coli strains isolated from dogs (n = 134), their owners (n = 134), and humans who claim to have no contact with dogs (n = 44, control), searching for sharing of strains. The strains were assessed for their genetic relatedness by phylogenetic grouping and pulsed-field gel electrophoresis. Multiresistant E. coli strains were isolated from 42 (31.3%) fecal samples from pairs of dogs and owners, totaling 84 isolates, and from 19 (43.1%) control group subjects. The strains showed high levels of resistance to ampicillin, streptomycin, tetracycline, trimethoprim and sulfamethoxazole regardless of host species or group of origin. The blaTEM, blaCTX-M, and blaSHV genes were detected in similar proportions in all groups. All isolates positive for bla genes were ESBL producers. The phylogenetic group A was the most prevalent, irrespective of the host species. None of the strains belonging to the B2 group contained bla genes. Similar resistance patterns were found for strains from dogs, owners and controls; furthermore, identical PFGE profiles were detected in four (9.5%) isolate pairs from dogs and owners, denoting the sharing of strains. Pet dogs were shown to be a potential household source of multiresistant E. coli strains. PMID:26887238

  6. Quantitative detection of antibiotic resistance genes using magnetic/luminescent core-shell nanoparticles

    Science.gov (United States)

    Son, Ahjeong; Hristova, Krassimira R.; Dosev, Dosi; Kennedy, Ian M.

    2008-02-01

    Nanoscale magnetic/luminescent core-shell particles were used for DNA quantification in a hybridization-in-solution format. We demonstrated a simple, high-throughput, and non-PCR based DNA assay for quantifying antibiotic resistance gene tetQ. Fe 3O 4/Eu:Gd IIO 3 nanoparticles (NPs) synthesized by spray pyrolysis were biofunctionalized by passive adsorption of NeutrAvidin. Following immobilization of biotinylated probe DNA on the particles' surfaces, target dsDNA and signaling probe DNA labeled with Cy3 were hybridized with NPs-probe DNA. Hybridized DNA complexes were separated from solution by a magnet, while non-hybridized DNA remained in solution. A linear quantification (R2 = 0.99) of a target tetQ gene was achieved based on the normalized fluorescence (Cy3/NPs) of DNANP hybrids. A real-time qPCR assay was used for evaluation of the NPs assay sensitivity and range of quantification. The quantity of antibiotic resistance tetQ genes in activated sludge microcosms, with and without addition of tetracycline or triclosan has been determined, indicating the potential of the optimized assay for monitoring the level of antibiotic resistance in environmental samples. In addition, the tetQ gene copy numbers in microcosms determined by NPhybridization were well correlated with the numbers measured by real-time qPCR assay (R2 = 0.92).

  7. Antibiotic-Resistance Genes in Waste Water.

    Science.gov (United States)

    Karkman, Antti; Do, Thi Thuy; Walsh, Fiona; Virta, Marko P J

    2017-10-12

    Waste water and waste water treatment plants can act as reservoirs and environmental suppliers of antibiotic resistance. They have also been proposed to be hotspots for horizontal gene transfer, enabling the spread of antibiotic resistance genes between different bacterial species. Waste water contains antibiotics, disinfectants, and metals which can form a selection pressure for antibiotic resistance, even in low concentrations. Our knowledge of antibiotic resistance in waste water has increased tremendously in the past few years with advances in the molecular methods available. However, there are still some gaps in our knowledge on the subject, such as how active is horizontal gene transfer in waste water and what is the role of the waste water treatment plant in the environmental resistome? The purpose of this review is to briefly describe some of the main methods for studying antibiotic resistance in waste waters and the latest research and main knowledge gaps on the issue. In addition, some future research directions are proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. [Cyclooxigenase-1 gene polymorphism and aspirin resistance].

    Science.gov (United States)

    Bondar', T N; Kravchenko, N A

    2012-01-01

    The literature data concerning structure of cyclo-oxigenase-1--the key enzyme in prostaglandin biosynthesis and the main target of anti-platelet therapy with the use of acetylsalicilic acid are presented in the review. The data on cyclooxigenase-1 gene polymorphism, distribution of the revealed variants in various populations and their possible correlation with biochemical and functional aspirin resistance are presented.

  9. Molecular screening for erythromycin resistance genes in ...

    African Journals Online (AJOL)

    Aghomotsegin

    2015-07-15

    Jul 15, 2015 ... Key words: Streptococcus pyogenes, molecular identification, erythromycin resistance genes. INTRODUCTION. Streptococcus pyogenes is the ... comprising a change in domain V of 23S rRNA as a result of a mutation in all the six copies of ..... New understanding of the group A Streptococcus pathogenesis ...

  10. Whole-genome sequencing of gentamicin-resistant Campylobacter coli isolated from U.S. retail meats reveals novel plasmid-mediated aminoglycoside resistance genes.

    Science.gov (United States)

    Chen, Yuansha; Mukherjee, Sampa; Hoffmann, Maria; Kotewicz, Michael L; Young, Shenia; Abbott, Jason; Luo, Yan; Davidson, Maureen K; Allard, Marc; McDermott, Patrick; Zhao, Shaohua

    2013-11-01

    Aminoglycoside resistance in Campylobacter has been routinely monitored in the United States in clinical isolates since 1996 and in retail meats since 2002. Gentamicin resistance first appeared in a single human isolate of Campylobacter coli in 2000 and in a single chicken meat isolate in 2007, after which it increased rapidly to account for 11.3% of human isolates and 12.5% of retail isolates in 2010. Pulsed-field gel electrophoresis analysis indicated that gentamicin-resistant C. coli isolates from retail meat were clonal. We sequenced the genomes of two strains of this clone using a next-generation sequencing technique in order to investigate the genetic basis for the resistance. The gaps of one strain were closed using optical mapping and Sanger sequencing, and this is the first completed genome of C. coli. The two genomes are highly similar to each other. A self-transmissible plasmid carrying multiple antibiotic resistance genes was revealed within both genomes, carrying genes encoding resistance to gentamicin, kanamycin, streptomycin, streptothricin, and tetracycline. Bioinformatics analysis and experimental results showed that gentamicin resistance was due to a phosphotransferase gene, aph(2")-Ig, not described previously. The phylogenetic relationship of this newly emerged clone to other Campylobacter spp. was determined by whole-genome single nucleotide polymorphisms (SNPs), which showed that it clustered with the other poultry isolates and was separated from isolates from livestock.

  11. Antibiotic resistance and virulence genes in enterococcus strains isolated from different hospitals in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Mohamed M. Hassan

    2016-07-01

    Full Text Available The purpose of this study was molecular characterization of the antibiotic resistance profiles of some Enterococcus isolates obtained from different hospitals in Taif governorate in KSA. Out of the 89 bacterial isolates obtained, 12 isolates of Enterococcus spp. were subjected to fingerprinting based on repetitive sequence-based polymerase chain reaction (Rep-PCR, and tested their resistance/susceptibility against some antibiotics which are commonly used in KSA. They were identified using the specific primers for different antibiotic resistance genes of Enterococcus spp. as Tuf, VanC-1, VanC-2-VanC-3 genes and sequencing fragments of 16S rDNA gene. The obtained results indicated that about 58.3% of Enterococcus isolates were Enterococcus faecium, 16.6% were Enterococcus durans and 25.1% were other Enterococcus species. Sixty-seven per cent of the isolates had multi-drug resistance patterns against gentamicin, vancomycin, erythromycin, amoxicillin, cefazolin and tetracycline. Data on the prevalence and types of antibiotic resistance in Enterococcus species may be used to describe baseline antibiotic susceptibility profiles associated with Enterococcus spp. that were isolated from the hospitals’ environment. Some discrepancies were detected among the identification methods used, and the most reliable were the Tuf, VanC-1, VanC-2-VanC-3 genes, and 16S rDNA nucleotide sequencing of 12 Enterococcus isolates were deposited in Gene Bank under the accession numbers from KT366721 to KT366732, respectively. Selected isolates exhibited susceptibility to almost all studied antibiotics, and some virulence factors were detected by PCR. Finally, these Enterococcus isolates were molecularly characterized by Rep-PCR into a diverse genetic background. The data collected may also help to elucidate the role of hospitals in the transmission of antibiotic-resistant strains to human populations.

  12. Antibiotic resistant bacteria/genes dissemination in lacustrine sediments highly increased following cultural eutrophication of Lake Geneva (Switzerland).

    Science.gov (United States)

    Thevenon, Florian; Adatte, Thierry; Wildi, Walter; Poté, John

    2012-02-01

    This study investigates faecal indicator bacteria (FIB), multiple antibiotic resistant (MAR), and antibiotic resistance genes (ARGs), of sediment profiles from different parts of Lake Geneva (Switzerland) over the last decades. MARs consist to expose culturable Escherichia coli (EC) and Enterococcus (ENT) to mixed five antibiotics including Ampicillin, Tetracycline, Amoxicillin, Chloramphenicol and Erythromycin. Culture-independent is performed to assess the distribution of ARGs responsible for, β-lactams (blaTEM; Amoxicillin/Ampicillin), Streptomycin/Spectinomycin (aadA), Tetracycline (tet) Chloramphenicol (cmlA) and Vancomycin (van). Bacterial cultures reveal that in the sediments deposited following eutrophication of Lake Geneva in the 1970s, the percentage of MARs to five antibiotics varied from 0.12% to 4.6% and 0.016% to 11.6% of total culturable EC and ENT, respectively. In these organic-rich bacteria-contaminated sediments, the blaTEM resistant of FIB varied from 22% to 48% and 16% to 37% for EC and ENT respectively, whereas the positive PCR assays responsible for tested ARGs were observed for EC, ENT, and total DNA from all samples. The aadA resistance gene was amplified for all the sediment samples, including those not influenced by WWTP effluent water. Our results demonstrate that bacteria MARs and ARGs highly increased in the sediments contaminated with WWTP effluent following the cultural eutrophication of Lake Geneva. Hence, the human-induced changing limnological conditions highly enhanced the sediment microbial activity, and therein the spreading of antibiotic resistant bacteria and genes in this aquatic environment used to supply drinking water in a highly populated area. Furthermore, the presence of the antibiotic resistance gene aadA in all the studied samples points out a regional dissemination of this emerging contaminant in freshwater sediments since at least the late nineteenth century. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Novel gentamicin resistance genes in Campylobacter isolated from humans and retail meats in the USA.

    Science.gov (United States)

    Zhao, Shaohua; Mukherjee, Sampa; Chen, Yuansha; Li, Cong; Young, Shenia; Warren, Melissa; Abbott, Jason; Friedman, Sharon; Kabera, Claudine; Karlsson, Maria; McDermott, Patrick F

    2015-05-01

    To understand the molecular epidemiology of gentamicin-resistant Campylobacter and investigate aminoglycoside resistance mechanisms. One-hundred-and-fifty-one gentamicin-resistant Campylobacter isolates from humans (n = 38 Campylobacter jejuni; n = 41, Campylobacter coli) and retail chickens (n = 72 C. coli), were screened for the presence of gentamicin resistance genes by PCR and subtyped using PFGE. A subset of the isolates (n = 41) was analysed using WGS. Nine variants of gentamicin resistance genes were identified: aph(2″)-Ib, Ic, Ig, If, If1, If3, Ih, aac(6')-Ie/aph(2″)-Ia and aac(6')-Ie/aph(2″)-If2. The aph(2″)-Ib, Ic, If1, If3, Ih and aac(6')-Ie/aph(2″)-If2 variants were identified for the first time in Campylobacter. Human isolates showed more diverse aminoglycoside resistance genes than did retail chicken isolates, in which only aph(2″)-Ic and -Ig were identified. The aph(2″)-Ig gene was only gene shared by C. coli isolates from human (n = 27) and retail chicken (n = 69). These isolates displayed the same resistance profile and similar PFGE patterns, suggesting that contaminated retail chicken was probably the source of human C. coli infections. Human isolates were genetically diverse and generally more resistant than the retail chicken isolates. The most frequent co-resistance was to tetracycline (78/79, 98.7%), followed by ciprofloxacin/nalidixic acid (46/79, 58.2%), erythromycin and azithromycin (36/79, 45.6%), telithromycin (32/79, 40.5%) and clindamycin (18/79, 22.8%). All human and retail meat isolates were susceptible to florfenicol. This study demonstrated that several new aminoglycoside resistance genes underlie the recent emergence of gentamicin-resistant Campylobacter, and that, in addition to contaminated retail chicken, other sources have also contributed to gentamicin-resistant Campylobacter infections in humans. Published by Oxford University Press on behalf of the British Society for Antimicrobial

  14. Antimicrobial resistance genes in marine bacteria and human uropathogenic Escherichia coli from a region of intensive aquaculture.

    Science.gov (United States)

    Tomova, Alexandra; Ivanova, Larisa; Buschmann, Alejandro H; Rioseco, Maria Luisa; Kalsi, Rajinder K; Godfrey, Henry P; Cabello, Felipe C

    2015-10-01

    Antimicrobials are heavily used in Chilean salmon aquaculture. We previously found significant differences in antimicrobial-resistant bacteria between sediments from an aquaculture and a non-aquaculture site. We now show that levels of antimicrobial resistance genes (ARG) are significantly higher in antimicrobial-selected marine bacteria than in unselected bacteria from these sites. While ARG in tetracycline- and florfenicol-selected bacteria from aquaculture and non-aquaculture sites were equally frequent, there were significantly more plasmid-mediated quinolone resistance genes per bacterium and significantly higher numbers of qnrB genes in quinolone-selected bacteria from the aquaculture site. Quinolone-resistant urinary Escherichia coli from patients in the Chilean aquacultural region were significantly enriched for qnrB (including a novel qnrB gene), qnrS, qnrA and aac(6')-1b, compared with isolates from New York City. Sequences of qnrA1, qnrB1 and qnrS1 in quinolone-resistant Chilean E. coli and Chilean marine bacteria were identical, suggesting horizontal gene transfer between antimicrobial-resistant marine bacteria and human pathogens. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Erythromycin-resistant genes in group A β-haemolytic Streptococci in Chengdu, Southwestern China.

    Science.gov (United States)

    Zhou, W; Jiang, Y M; Wang, H J; Kuang, L H; Hu, Z Q; Shi, H; Shu, M; Wa, C M

    2014-01-01

    The management of Group A β-haemolytic Streptococci (Streptococcus pyogenes or GAS) infection include the use of penicillins, cephalosporins or macrolides for treatment. A general increase in macrolides resistance in GAS has been observed in recent years. Differences in rates of resistance to these agents have existed according to geographical location and investigators. To investigate the antibiotic pattern and erythromycin-resistant genes of GAS isolates associated with acute tonsillitis and scarlet fever in Chengdu, southwestern China. To assess the macrolide resistance, phenotype, and genotypic characterization of GAS isolated from throat swabs of children suffering from different acute tonsillitis or scarlet fever between 2004 and 2011 in the city of Chengdu, located in the southwestern region of China. Minimal inhibitory concentration with seven antibiotics was performed on 127 GAS isolates. Resistance phenotypes of erythromycin-resistant GAS isolates were determined by the double-disk test. Their macrolide-resistant genes (mefA, ermB and ermTR) were amplified by PCR. A total of 98.4% (125/127) of the isolates exhibited resistance to erythromycin, clindamycin and tetracycline. All isolates were sensitive to penicillin G and cefotaxime. Moreover, 113 ermB-positive isolates demonstrating the cMLS phenotype of erythromycin resistance were predominant (90.4%) and these isolates showed high-level resistance to both erythromycin and clindamycin (MIC 90>256 μg/ml); 12 (9.6%) isolates demonstrating the MLS phenotype of erythromycin resistance carried the mefA gene, which showed low-level resistance to both erythromycin (MIC 90=8 μg/ml) and clindamycin (MIC 90=0.5 μg/ml); and none of the isolates exhibited the M phenotype. The main phenotype is cMLS, and the ermB gene code is the main resistance mechanism against macrolides in GAS. Penicillin is the most beneficial for treating GAS infection, and is still used as first-line treatment. And macrolide antibiotics are

  16. Detection of selected antibiotic resistance genes using multiplex PCR assay in mastitis pathogens in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Vladimir Pyatov

    2017-01-01

    Full Text Available The aim of this research was to develop multiplex polymerase chain reaction assays for the detection of aminoglycoside (strA, strB, sulphonamide (sulI, sulII, tetracycline (tetA, tetB, tetK, tetM, tetO, macrolide and lincosamide (msrA, ermA, ermB, ermC, mefA/E genes of resistance in mastitis pathogens (Escherichia coli, Staphylococcus aureus, Streptococcus uberis, Streptococcus agalactiae and Streptococcus dysgalactiae. Applying the established assays, we investigated the distribution of antibiotic resistance genes in the above mentioned species isolated from milk samples in the Czech Republic. Each assay consisted of seven pairs of primers. Six of them amplified fragments of antibiotic resistance genes and one pair a fragment of a species specific gene. Polymerase chain reaction conditions were optimized to amplify seven gene fragments simultaneously in one reaction. In total, 249 isolates were used, among which 111 were positive for E. coli, 52 for S. aureus and 86 for Streptococcus spp. The majority (60.2% of bacteria carried at least one antibiotic resistance gene and 44.6% were multidrug-resistant. The designed multiplex polymerase chain reaction assays may be applied as diagnostic method to replace or complement standard techniques of antibiotic susceptibility testing in the mentioned pathogens.

  17. Multidrug-Resistant Escherichia albertii: Co-occurrence of β-Lactamase and MCR-1 Encoding Genes

    Directory of Open Access Journals (Sweden)

    Qun Li

    2018-02-01

    Full Text Available Escherichia albertii is an emerging member of the Enterobacteriaceae causing human and animal enteric infections. Antimicrobial resistance among enteropathogens has been reported to be increasing in the past years. The purpose of this study was to investigate antibiotic resistance and resistance genes in E. albertii isolated from Zigong city, Sichuan province, China. The susceptibility to 21 antimicrobial agents was determined by Kirby–Bauer disk diffusion method. The highest prevalence was tetracycline resistance with a rate of 62.7%, followed by resistance to nalidixic acid and streptomycin with a rate of 56.9 and 51.0%, respectively. All isolates were sensitive or intermediate susceptible to imipenem, meropenem, amoxicillin–clavulanic acid, and levofloxacin. Among 51 E. albertii isolates, 15 were extended-spectrum β-lactamase-producing as confirmed by the double disk test. The main β-lactamase gene groups, i.e., blaTEM, blaSHV, and blaCTX-M, were detected in17, 20, and 22 isolates, respectively. Furthermore, four colistin-resistant isolates with minimum inhibitory concentrations of 8 mg/L were identified. The colistin-resistant isolates all harbored mcr-1 and blaCTX-M-55. Genome sequencing showed that E. albertii strain SP140150 carried mcr-1 and blaCTX-M-55 in two different plasmids. This study provided significant information regarding antibiotic resistance profiles and identified the co-occurrence of β-lactamase and MCR-1 encoding genes in E. albertii isolates.

  18. Monitoring Antibiotic Residues and Corresponding Antibiotic Resistance Genes in an Agroecosystem

    Directory of Open Access Journals (Sweden)

    Yasser M. Awad

    2015-01-01

    Full Text Available Antibiotic resistance genes (ARGs have been commonly reported due to the overuse worldwide of antibiotics. Antibiotic overuse disturbs the environment and threatens public human health. The objective of this study was to measure the residual concentrations of veterinary antibiotics in the tetracycline group (TCs, including tetracycline (TC and chlortetracycline (CTC, as well as those in the sulfonamide group (SAs, including sulfamethazine (SMT, sulfamethoxazole (SMX, and sulfathiazole (STZ. We also isolated the corresponding ARGs in the agroecosystem. Four sediment samples and two rice paddy soil samples were collected from sites near a swine composting facility along the Naerincheon River in Hongcheon, Korea. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS was employed with a solid-phase extraction method to measure the concentration of each antibiotic. ARGs were identified by the qualitative polymerase chain-reaction using synthetic primers. SAs and their corresponding ARGs were highly detected in sediment samples whereas TCs were not detected except for sediments sample #1. ARGs for TCs and SAs were detected in rice paddy soils, while ARGs for TCs were only found in sediment #2 and #4. Continuous monitoring of antibiotic residue and its comprehensive impact on the environment is needed to ensure environmental health.

  19. Functional Repertoire of Antibiotic Resistance Genes in Antibiotic Manufacturing Effluents and Receiving Freshwater Sediments.

    Science.gov (United States)

    González-Plaza, Juan J; Šimatović, Ana; Milaković, Milena; Bielen, Ana; Wichmann, Fabienne; Udiković-Kolić, Nikolina

    2017-01-01

    Environments polluted by direct discharges of effluents from antibiotic manufacturing are important reservoirs for antibiotic resistance genes (ARGs), which could potentially be transferred to human pathogens. However, our knowledge about the identity and diversity of ARGs in such polluted environments remains limited. We applied functional metagenomics to explore the resistome of two Croatian antibiotic manufacturing effluents and sediments collected upstream of and at the effluent discharge sites. Metagenomic libraries built from an azithromycin-production site were screened for resistance to macrolide antibiotics, whereas the libraries from a site producing veterinary antibiotics were screened for resistance to sulfonamides, tetracyclines, trimethoprim, and beta-lactams. Functional analysis of eight libraries identified a total of 82 unique, often clinically relevant ARGs, which were frequently found in clusters and flanked by mobile genetic elements. The majority of macrolide resistance genes identified from matrices exposed to high levels of macrolides were similar to known genes encoding ribosomal protection proteins, macrolide phosphotransferases, and transporters. Potentially novel macrolide resistance genes included one most similar to a 23S rRNA methyltransferase from Clostridium and another, derived from upstream unpolluted sediment, to a GTPase HflX from Emergencia . In libraries deriving from sediments exposed to lower levels of veterinary antibiotics, we found 8 potentially novel ARGs, including dihydrofolate reductases and beta-lactamases from classes A, B, and D. In addition, we detected 7 potentially novel ARGs in upstream sediment, including thymidylate synthases, dihydrofolate reductases, and class D beta-lactamase. Taken together, in addition to finding known gene types, we report the discovery of novel and diverse ARGs in antibiotic-polluted industrial effluents and sediments, providing a qualitative basis for monitoring the dispersal of ARGs

  20. Exploring the correlations between antibiotics and antibiotic resistance genes in the wastewater treatment plants of hospitals in Xinjiang, China.

    Science.gov (United States)

    Li, Chao; Lu, Jianjiang; Liu, Jiang; Zhang, Genlin; Tong, Yanbing; Ma, Na

    2016-08-01

    Various antibiotics have been extensively used to treating infectious diseases in hospitals. In this study, the abundance and diversity of antibiotics and antibiotic resistance genes (ARGs) were observed in the wastewater samples from five hospitals in Xinjiang, China. The total concentrations of tetracyclines, sulphonamides, and quinolones in hospital influents ranged from 363.4 to 753.3 ng/L, 285.5 to 634.9 ng/L, and 1355.8 to 1922.4 ng/L, respectively. However, the removal efficiency of tetracyclines, sulphonamides, and quinolones in wastewater treatment processes ranged from 72.4 to 79.3 %, 36.0 to 52.2 %, and 45.1 to 55.4 %, respectively. The contamination levels of the selected ARGs varied in all wastewater samples. The highest relative concentrations of sul1, sul2, tetQ, and qnrS were significantly higher than those of other ARGs in this study. Significant positive correlations between the relative abundance of partial ARGs and concentrations of certain antibiotics were observed in hospital wastewaters. Results show that integrons played an important role in disseminating and distributing ARGs in microorganism systems. Furthermore, strong correlations were observed between tetQ, sulphonamide resistance genes (except sulA) and intI1. This study aimed to determine the contamination levels of antibiotics and ARGs and analyze the relationships among ARGs, and antibiotics and integron genes in hospital wastewaters.

  1. Antibiotic resistance genes, integrons and multiple antibiotic resistance in thirty-five serotypes of Salmonella enterica isolated from humans and animals in the UK

    National Research Council Canada - National Science Library

    Randall, L P; Cooles, S W; Osborn, M K; Piddock, L J V; Woodward, M J

    2004-01-01

    .... Some strains were resistant to ampicillin (91), chloramphenicol (85), gentamicin (2), kanamycin (14), spectinomycin (81), streptomycin (119), sulfadiazine (127), tetracycline (108) and trimethoprim (45); 219 strains were susceptible to all antibiotics...

  2. Antibiotic resistance genes in surface water of eutrophic urban lakes are related to heavy metals, antibiotics, lake morphology and anthropic impact.

    Science.gov (United States)

    Yang, Yuyi; Xu, Chen; Cao, Xinhua; Lin, Hui; Wang, Jun

    2017-08-01

    Urban lakes are impacted by heavy human activities and represent potential reservoirs for antibiotic resistance genes. In this study, six urban lakes in Wuhan, central China were selected to analyze the distribution of sulfonamide resistance (sul) genes, tetracycline resistance (tet) genes and quinolone resistance (qnr) genes and their relationship with heavy metals, antibiotics, lake morphology and anthropic impact. sul1 and sul2 were detected in all six lakes and dominated the types of antibiotic resistance genes, which accounted for 86.28-97.79% of the total antibiotic resistance gene abundance. For eight tested tet genes, antibiotic efflux pumps (tetA, tetB, tetC, and tetG) genes were all observed in six lakes and had higher relative abundance than ribosomal protection protein genes (tetM and tetQ). For 4 plasmid mediated quinolone resistance genes, only qnrD is found in all six lakes. The class I integron (intI1) is also found to be a very important media for antibiotic resistance gene propagation in urban lakes. The results of redundancy analysis and variation partitioning analysis showed that antibiotic and co-selection with heavy metals were the major factors driving the propagation of antibiotic resistance genes in six urban lakes. The heavily eutrophic Nanhu Lake and Shahu Lake which located in a high density building area with heavy human activities had the higher relative abundance of total antibiotic resistance genes. Our study could provide a useful reference for antibiotic resistance gene abundance in urban lakes with high anthropic impact.

  3. Conjugative multi-resistant plasmids in Haihe River and their impacts on the abundance and spatial distribution of antibiotic resistance genes.

    Science.gov (United States)

    Dang, Bingjun; Mao, Daqing; Xu, Yan; Luo, Yi

    2017-03-15

    In this study, five classes of antibiotic resistance genes (ARGs) were quantified in sediment samples of Haihe River, China, with abundance ranging from 1.39 × 104 to 1.58 × 1010 copies/g dry weight. Meanwhile, antibiotic resistant conjugative plasmids were also isolated from these samples through filter mating assays. In total, 202 transconjugants were isolated and tested for their antibiotic resistance phenotypes, among which 26 different types of conjugative plasmids were observed. The majority of these plasmids showed a multi-resistant phenotype and the most prevalent resistance was tetracycline resistance and sulfonamide resistance. Furthermore, we tested the transfer frequencies of these plasmids, determined their genotypes and then compared the plasmid-borne ARGs with their corresponding abundance in Haihe River. Most of the isolated plasmids exhibited high transfer frequencies to the recipient strain Escherichia coli J53. Plasmids isolated from the urban areas of Haihe River have higher transfer frequencies than the rural areas. Results from comprehensive analysis of plasmid genotypes, ARG abundance and plasmid sequencing confirmed that most of the plasmid-borne ARGs were the dominant genes in the Haihe River. Therefore, conjugative plasmids isolated from the Haihe River plays a crucial role in the dissemination, abundance and spatial distribution of ARGs in Haihe River, especially some unfrequent ARGs like blaGES-1. This study will help to increase the knowledge on the conjugative plasmid-mediated ARG propagation in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Effects of electron acceptors on removal of antibiotic resistant Escherichia coli, resistance genes and class 1 integrons under anaerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Heyang; Miller, Jennifer H. [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Abu-Reesh, Ibrahim M. [Department of Chemical Engineering, Qatar University, P.O. Box 2713, Doha (Qatar); Pruden, Amy [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); He, Zhen, E-mail: zhenhe@vt.edu [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States)

    2016-11-01

    Anaerobic biotechnologies can effectively remove antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), but there is a need to better understand the mechanisms. Here we employ bioelectrochemical systems (BES) as a platform to investigate the fate of a native tetracycline and sulfonamide-resistant Escherichia coli strain and its ARGs. The E. coli strain carrying intI1, sulI and tet(E) was isolated from domestic wastewater and dosed into a tubular BES. The BES was first operated as a microbial fuel cell (MFC), with aeration in the cathode, which resulted in enhanced removal of E. coli and ARGs by ~ 2 log (i.e., order of magnitude) when switched from high current to open circuit operation mode. The BES was then operated as a microbial electrolysis cell (MEC) to exclude the effects of oxygen diffusion, and the removal of E. coli and ARGs during the open circuit configuration was again 1–2 log higher than that at high current mode. Significant correlations of E. coli vs. current (R{sup 2} = 0.73) and ARGs vs. E. coli (R{sup 2} ranged from 0.54 to 0.87), and the fact that the BES substrate contained no electron acceptors, implied that the persistence of the E. coli and its ARGs was determined by the availability of indigenous electron acceptors in the BES, i.e., the anode electrode or the electron shuttles generated by the exoelectrogens. Subsequent experiments with pure-culture tetracycline and sulfonamide-resistant E. coli being incubated in a two-chamber MEC and serum bottles demonstrated that the E. coli could survive by respiring anode electrode and/or electron shuttles released by exoelectrogens, and ARGs persisted with their host E. coli. - Highlights: • The fate of an antibiotic resistant E. coli stain and its ARGs in BES is studied. • The removal of the E. coli and its ARGs is enhanced with decreased current. • The ARGs are removed when the host E. coli dies and persist when the host survives. • The survival of the E. coli depends

  5. Genome Comparison of Erythromycin Resistant Campylobacter from Turkeys Identifies Hosts and Pathways for Horizontal Spread of erm(B Genes

    Directory of Open Access Journals (Sweden)

    Diego Florez-Cuadrado

    2017-11-01

    Full Text Available Pathogens in the genus Campylobacter are the most common cause of food-borne bacterial gastro-enteritis. Campylobacteriosis, caused principally by Campylobacter jejuni and Campylobacter coli, is transmitted to humans by food of animal origin, especially poultry. As for many pathogens, antimicrobial resistance in Campylobacter is increasing at an alarming rate. Erythromycin prescription is the treatment of choice for clinical cases requiring antimicrobial therapy but this is compromised by mobility of the erythromycin resistance gene erm(B between strains. Here, we evaluate resistance to six antimicrobials in 170 Campylobacter isolates (133 C. coli and 37 C. jejuni from turkeys. Erythromycin resistant isolates (n = 85; 81 C. coli and 4 C. jejuni were screened for the presence of the erm(B gene, that has not previously been identified in isolates from turkeys. The genomes of two positive C. coli isolates were sequenced and in both isolates the erm(B gene clustered with resistance determinants against aminoglycosides plus tetracycline, including aad9, aadE, aph(2″-IIIa, aph(3′-IIIa, and tet(O genes. Comparative genomic analysis identified identical erm(B sequences among Campylobacter from turkeys, Streptococcus suis from pigs and Enterococcus faecium and Clostridium difficile from humans. This is consistent with multiple horizontal transfer events among different bacterial species colonizing turkeys. This example highlights the potential for dissemination of antimicrobial resistance across bacterial species boundaries which may compromise their effectiveness in antimicrobial therapy.

  6. Genome Comparison of Erythromycin Resistant Campylobacter from Turkeys Identifies Hosts and Pathways for Horizontal Spread of erm(B) Genes.

    Science.gov (United States)

    Florez-Cuadrado, Diego; Ugarte-Ruiz, María; Meric, Guillaume; Quesada, Alberto; Porrero, M C; Pascoe, Ben; Sáez-Llorente, Jose L; Orozco, Gema L; Domínguez, Lucas; Sheppard, Samuel K

    2017-01-01

    Pathogens in the genus Campylobacter are the most common cause of food-borne bacterial gastro-enteritis. Campylobacteriosis, caused principally by Campylobacter jejuni and Campylobacter coli, is transmitted to humans by food of animal origin, especially poultry. As for many pathogens, antimicrobial resistance in Campylobacter is increasing at an alarming rate. Erythromycin prescription is the treatment of choice for clinical cases requiring antimicrobial therapy but this is compromised by mobility of the erythromycin resistance gene erm(B) between strains. Here, we evaluate resistance to six antimicrobials in 170 Campylobacter isolates (133 C. coli and 37 C. jejuni) from turkeys. Erythromycin resistant isolates (n = 85; 81 C. coli and 4 C. jejuni) were screened for the presence of the erm(B) gene, that has not previously been identified in isolates from turkeys. The genomes of two positive C. coli isolates were sequenced and in both isolates the erm(B) gene clustered with resistance determinants against aminoglycosides plus tetracycline, including aad9, aadE, aph(2″)-IIIa, aph(3')-IIIa, and tet(O) genes. Comparative genomic analysis identified identical erm(B) sequences among Campylobacter from turkeys, Streptococcus suis from pigs and Enterococcus faecium and Clostridium difficile from humans. This is consistent with multiple horizontal transfer events among different bacterial species colonizing turkeys. This example highlights the potential for dissemination of antimicrobial resistance across bacterial species boundaries which may compromise their effectiveness in antimicrobial therapy.

  7. A Comprehensive Analysis on Spread and Distribution Characteristic of Antibiotic Resistance Genes in Livestock Farms of Southeastern China.

    Science.gov (United States)

    Wang, Na; Guo, Xinyan; Yan, Zheng; Wang, Wei; Chen, Biao; Ge, Feng; Ye, Boping

    2016-01-01

    The pollution of antibiotic resistance genes (ARGs) in livestock farms is a problem which need to be paid more attention to, due to the severe resistance dissemination and the further human health risk. In this study, all the relevant exposure matrices (manure, soil and water) of sixteen animal farms in Southeastern China were sampled to determine twenty-two ARGs conferring resistance to five major classes of antibiotics including tetracyclines, sulfonamides, quinolones, aminoglycosides, and macrolides. The results showed that the spread property of sul genes was most extensive and strong, followed by tet and erm genes. The abundance of tet genes expressing ribosomal protection proteins (tetM, tetO, tetQ, tetT and tetW) was higher than that expressing efflux pump proteins (tetA, tetC, tetE and tetG) in each type of samples. The high abundance and frequency of ermB gene in the matrices should be paid more attention, because macrolides is a major medicine for human use. For manures, it was found that the similar ARGs distribution rules were existing in poultry manure or porcine manure samples, despite of the different origins of these two types of livestock farms. Meanwhile, it was interesting that the distribution rule of tet genes in animal manure was nearly the same as all the ARGs. For soils, the result of nonmetric multi-dimensional scaling (NMDS) analysis showed that the pollution of ARGs in the soils fertilized by poultry and cattle manures were more substantial in northern Jiangsu, but no significant ARGs diversity was observed among porcine manured soils of five different regions. Furthermore, most ARGs showed significant positive relationships with environmental variables such as concentration of sulfonamides, tetracyclines, Cu, Zn and total organic carbon (TOC). The pollution profile and characteristics of so many ARGs in livestock farms can provide significative foundation for the regulation and legislation of antibiotics in China.

  8. A Comprehensive Analysis on Spread and Distribution Characteristic of Antibiotic Resistance Genes in Livestock Farms of Southeastern China.

    Directory of Open Access Journals (Sweden)

    Na Wang

    Full Text Available The pollution of antibiotic resistance genes (ARGs in livestock farms is a problem which need to be paid more attention to, due to the severe resistance dissemination and the further human health risk. In this study, all the relevant exposure matrices (manure, soil and water of sixteen animal farms in Southeastern China were sampled to determine twenty-two ARGs conferring resistance to five major classes of antibiotics including tetracyclines, sulfonamides, quinolones, aminoglycosides, and macrolides. The results showed that the spread property of sul genes was most extensive and strong, followed by tet and erm genes. The abundance of tet genes expressing ribosomal protection proteins (tetM, tetO, tetQ, tetT and tetW was higher than that expressing efflux pump proteins (tetA, tetC, tetE and tetG in each type of samples. The high abundance and frequency of ermB gene in the matrices should be paid more attention, because macrolides is a major medicine for human use. For manures, it was found that the similar ARGs distribution rules were existing in poultry manure or porcine manure samples, despite of the different origins of these two types of livestock farms. Meanwhile, it was interesting that the distribution rule of tet genes in animal manure was nearly the same as all the ARGs. For soils, the result of nonmetric multi-dimensional scaling (NMDS analysis showed that the pollution of ARGs in the soils fertilized by poultry and cattle manures were more substantial in northern Jiangsu, but no significant ARGs diversity was observed among porcine manured soils of five different regions. Furthermore, most ARGs showed significant positive relationships with environmental variables such as concentration of sulfonamides, tetracyclines, Cu, Zn and total organic carbon (TOC. The pollution profile and characteristics of so many ARGs in livestock farms can provide significative foundation for the regulation and legislation of antibiotics in China.

  9. Effects of chlortetracycline and copper supplementation on the prevalence, distribution, and quantity of antimicrobial resistance genes in the fecal metagenome of weaned pigs.

    Science.gov (United States)

    Agga, Getahun E; Scott, H Morgan; Vinasco, Javier; Nagaraja, T G; Amachawadi, Raghavendra G; Bai, Jianfa; Norby, Bo; Renter, David G; Dritz, Steve S; Nelssen, Jim L; Tokach, Mike D

    2015-05-01

    Use of in-feed antibiotics such as chlortetracycline (CTC) in food animals is fiercely debated as a cause of antimicrobial resistance in human pathogens; as a result, alternatives to antibiotics such as heavy metals have been proposed. We used a total community DNA approach to experimentally investigate the effects of CTC and copper supplementation on the presence and quantity of antimicrobial resistance elements in the gut microbial ecology of pigs. Total community DNA was extracted from 569 fecal samples collected weekly over a 6-week period from groups of 5 pigs housed in 32 pens that were randomized to receive either control, CTC, copper, or copper plus CTC regimens. Qualitative and quantitative PCR were used to detect the presence of 14 tetracycline resistance (tet) genes and to quantify gene copies of tetA, tetB, blaCMY-2 (a 3rd generation cephalosporin resistance gene), and pcoD (a copper resistance gene), respectively. The detection of tetA and tetB decreased over the subsequent sampling periods, whereas the prevalence of tetC and tetP increased. CTC and copper plus CTC supplementation increased both the prevalence and gene copy numbers of tetA, while decreasing both the prevalence and gene copies of tetB. In summary, tet gene presence was initially very diverse in the gut bacterial community of weaned pigs; thereafter, copper and CTC supplementation differentially impacted the prevalence and quantity of the various tetracycline, ceftiofur and copper resistance genes resulting in a less diverse gene population. Published by Elsevier B.V.

  10. Characterisation of penA and tetM resistance genes of Neisseria ...

    African Journals Online (AJOL)

    Campos J, Fuste MC, Trujillo G, et al. Genetic diversity of penicillin-resistant. Neisseria meningitidis. J Infect Dis 1992; 166: 173-177. 8. Speer BS. Shoemaker NB. Salyers AA. Bacterial resistance to tetracycline: mechanisms, transfer and clinical significance. CUn Microbiol Rev 1992; 5: 387-399. 9. Morse SA, Johnson SR, ...

  11. Occurrence of plasmid-mediated quinolone resistance and virulence genes in avian Escherichia coli isolates from Algeria.

    Science.gov (United States)

    Laarem, Meradi; Barguigua, Abouddihaj; Nayme, Kaotar; Akila, Abdi; Zerouali, Khalid; El Mdaghri, Naima; Timinouni, Mohammed

    2017-02-28

    The emergence and spread of quinolone-resistant Escherichia coli in poultry products puts consumers at risk of exposure to the strains of E. coli that resist antibiotic treatment. The objective of this study was to define the prevalence and virulence potential of poultry-associated nalidixic acid (NAL)-resistant E. coli in the Annaba city, Algeria. In total, 33 samples of retail chicken meat were purchased from various butcher shops and examined for bacterial contamination with NAL-resistant E. coli. These isolates were subjected to antimicrobial susceptibility testing and were also investigated for the presence of plasmid-mediated quinolone resistance (PMQR) genes and virulence genes using conventional polymerase chain reaction (PCR) and DNA sequencing. Phylogenetic grouping of the NAL-resistant E. coli isolates was determined by the conventional multiplex PCR method. Twenty-nine (87.8%) products yielded NAL-resistant E. coli. Antibiograms revealed that 96.55% of NAL-resistant E. coli isolates were multidrug resistant (MDR). Resistance was most frequently observed against sulfamethoxazole-trimethoprim (96.6%), tetracycline (96.6%), ciprofloxacin (72%), and amoxicillin (65.5%). Group A was the most prevalent phylogenetic group, followed by groups D, B1, and B2. The PMQR determinants were detected in three isolates with qnrB72 and qnrS1 type identified. Four (13.8%) isolates carried one of the Shiga toxin E. coli-associated genes stx1, stx2, and ehxA alleles. The high prevalence of NAL-resistant E. coli isolated from retail chicken meat with detection of MDR E. coli harboring Shiga toxin genes in this study gives a warning signal for possible occurrence of foodborne infections with failure in antibiotic treatment.

  12. Genotypic and phenotypic β-lactam resistance and presence of PVL gene in Staphylococci from dry bovine udder.

    Directory of Open Access Journals (Sweden)

    Vinodkumar Kulangara

    Full Text Available Dairy cows affected with subclinical mastitis can be sources of virulent, antimicrobial-resistant Staphylococci to humans because of the excretion of the bacteria through their milk. This study focussed on the phenotypic and genotypic antibiotic resistance patterns of Staphylococci isolated from dairy cows in early dry period. Among 96 isolates of Gram positive cocci from 157 cows, 76 were identified as Coagulase Negative Staphylococci and the remaining 20 were Staphylococcus aureus. Typical amplicons of coagulase gene were obtained for all 20 samples of S. aureus with three major coagulase types being identified as giving 627 bp (40%, 910 bp (35% and 710 bp (25% long PCR products. The groEL gene was amplified in PCR of all 76 isolates of Coagulase Negative Staphylococci, and incubation of PCR products with restriction enzyme PvuII yielded three distinct PCR-RFLP fragment patterns bearing resemblance to S. chromogenes and S. hyicus. Highest sensitivity of Coagulase Negative Staphylococci was noted for Azithromycin (92.5% and the least to Tetracyclines (76.3%, whereas for S. aureus, it was Cefoperazone (95% and Azithromycin (72.2% respectively. Phenotypic resistance to Oxacillin (25 isolates, and Cefoxitin (11 isolates was detected by dilution method with a commercial strip (Ezy MICTM. Genotypic resistance to β-Lactam antibiotics was found in 65 (34 with mecA gene and 31 with blaZ gene isolates. Eighteen isolates possessed both the genes, with the PVL gene for virulence being detected in five of them. Nine isolates which had mecA gene were phenotypically susceptible to oxacillin while phenotypic resistance to oxacillin was observed in seven isolates that did not have either mecA or blaZ gene. This is the first report of persistent Staphylococcal infections possessing PVL gene and high level of genotypic resistance to β-Lactam antibiotics in small- holder dairy cattle from India.

  13. Characterization of Antimicrobial Resistance Patterns and Detection of Virulence Genes in Campylobacter Isolates in Italy

    Science.gov (United States)

    Di Giannatale, Elisabetta; Di Serafino, Gabriella; Zilli, Katiuscia; Alessiani, Alessandra; Sacchini, Lorena; Garofolo, Giuliano; Aprea, Giuseppe; Marotta, Francesca

    2014-01-01

    Campylobacter has developed resistance to several antimicrobial agents over the years, including macrolides, quinolones and fluoroquinolones, becoming a significant public health hazard. A total of 145 strains derived from raw milk, chicken faeces, chicken carcasses, cattle faeces and human faeces collected from various Italian regions, were screened for antimicrobial susceptibility, molecular characterization (SmaI pulsed-field gel electrophoresis) and detection of virulence genes (sequencing and DNA microarray analysis). The prevalence of C. jejuni and C. coli was 62.75% and 37.24% respectively. Antimicrobial susceptibility revealed a high level of resistance for ciprofloxacin (62.76%), tetracycline (55.86%) and nalidixic acid (55.17%). Genotyping of Campylobacter isolates using PFGE revealed a total of 86 unique SmaI patterns. Virulence gene profiles were determined using a new microbial diagnostic microarray composed of 70-mer oligonucleotide probes targeting genes implicated in Campylobacter pathogenicity. Correspondence between PFGE and microarray clusters was observed. Comparisons of PFGE and virulence profiles reflected the high genetic diversity of the strains examined, leading us to speculate different degrees of pathogenicity inside Campylobacter populations. PMID:24556669

  14. Characterization of Antimicrobial Resistance Patterns and Detection of Virulence Genes in Campylobacter Isolates in Italy

    Directory of Open Access Journals (Sweden)

    Elisabetta Di Giannatale

    2014-02-01

    Full Text Available Campylobacter has developed resistance to several antimicrobial agents over the years, including macrolides, quinolones and fluoroquinolones, becoming a significant public health hazard. A total of 145 strains derived from raw milk, chicken faeces, chicken carcasses, cattle faeces and human faeces collected from various Italian regions, were screened for antimicrobial susceptibility, molecular characterization (SmaI pulsed-field gel electrophoresis and detection of virulence genes (sequencing and DNA microarray analysis. The prevalence of C. jejuni and C. coli was 62.75% and 37.24% respectively. Antimicrobial susceptibility revealed a high level of resistance for ciprofloxacin (62.76%, tetracycline (55.86% and nalidixic acid (55.17%. Genotyping of Campylobacter isolates using PFGE revealed a total of 86 unique SmaI patterns. Virulence gene profiles were determined using a new microbial diagnostic microarray composed of 70-mer oligonucleotide probes targeting genes implicated in Campylobacter pathogenicity. Correspondence between PFGE and microarray clusters was observed. Comparisons of PFGE and virulence profiles reflected the high genetic diversity of the strains examined, leading us to speculate different degrees of pathogenicity inside Campylobacter populations.

  15. Exploring antibiotic resistance genes and metal resistance genes in plasmid metagenomes from wastewater treatment plants

    OpenAIRE

    Li, An-Dong; Li, Li-Guan; Zhang, Tong

    2015-01-01

    Plasmids operate as independent genetic elements in microorganism communities. Through horizontal gene transfer, they can provide their host microorganisms with important functions such as antibiotic resistance and heavy metal resistance. In this study, six metagenomic libraries were constructed with plasmid DNA extracted from influent, activated sludge and digested sludge of two wastewater treatment plants. Compared with the metagenomes of the total DNA extracted from the same sectors of the...

  16. Bacteriological water quality in school's drinking fountains and detection antibiotic resistance genes.

    Science.gov (United States)

    Gomes Freitas, Denize; Silva, Rassan Dyego Romão; Bataus, Luis Artur Mendes; Barbosa, Mônica Santiago; da Silva Bitencourt Braga, Carla Afonso; Carneiro, Lilian Carla

    2017-02-08

    The fecal coliform can contaminate water of human consumption causing problems to public health. Many of these microorganisms may contain plasmid and transfer them to other bacteria. This genetic material may confer selective advantages, among them resistance to antibiotics. The objectives of this study were to analyze the presence of fecal coliforms in water and at drinker surface, to identify the existence of plasmid, conducting studies of resistance to antibiotics, plasmid stability and capacity of bacterial conjugation. Were collected microorganisms in water of drinker surface and were used specific culture media and biochemical tests for identification of organisms, tests were performed by checking the resistance to antibiotics (ampicillin 10 μg, tetracycline 30 μg, and ciprofloxacin 5 μg), was performed extraction of plasmid DNA, plasmid stability and bacterial conjugation. Was obtained results of 31% of Salmonella spp. and 51% for other coliforms. Among the samples positive for coliforms, 27 had plasmid stable and with the ability to perform conjugation. The plasmids had similar forms, suggesting that the resistance in some bacteria may be linked to those genes extra chromosomal.

  17. Transformation of tetracycline by TetX and its subsequent degradation in a heterologous host.

    Science.gov (United States)

    Ghosh, Sudeshna; LaPara, Timothy M; Sadowsky, Michael J

    2015-06-01

    TetX is a flavin-dependent monooxygenase. It has been reported to inactivate all tested tetracyclines. In this study, Escherichia coli overexpressing TetX was added to soil bacterial enrichment cultures along with varying levels of tetracycline and was found to affect community-wide tetracycline resistance levels. Soil microbial communities developed lower levels of tetracycline resistance upon exposure to 25 μg/mL of tetracycline when an E. coli expressing TetX was present (6% of cultivable bacteria were resistant to 40 μg/mL tetracycline). In contrast, in the absence of TetX activity, a similar tetracycline exposure selected for greater levels of resistant bacteria in the soil microbial community (90% of cultivable bacteria were resistant to 40 μg/mL tetracycline). We also describe new metabolites formed after tetracycline transformation by TetX and report the transient generation of redox-active metabolite(s). The results presented here are particularly pertinent in the light of the recent emergence of tet(X) in different bacterial species, including clinical isolates. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Calcined Eggshell Waste for Mitigating Soil Antibiotic-Resistant Bacteria/Antibiotic Resistance Gene Dissemination and Accumulation in Bell Pepper.

    Science.gov (United States)

    Ye, Mao; Sun, Mingming; Feng, Yanfang; Li, Xu; Schwab, Arthur P; Wan, Jinzhong; Liu, Manqiang; Tian, Da; Liu, Kuan; Wu, Jun; Jiang, Xin

    2016-07-13

    The combined accumulation of antibiotics, heavy metals, antibiotic-resistant bacteria (ARB)/antibiotic resistance genes (ARGs) in vegetables has become a new threat to human health. This is the first study to investigate the feasibility of calcined eggshells modified by aluminum sulfate as novel agricultural wastes to impede mixed contaminants from transferring to bell pepper (Capsicum annuum L.). In this work, calcined eggshell amendment mitigated mixed pollutant accumulation in bell pepper significantly, enhanced the dissipation of soil tetracycline, sulfadiazine, roxithromycin, and chloramphenicol, decreased the water-soluble fractions of antibiotics, and declined the diversity of ARB/ARGs inside the vegetable. Moreover, quantitative polymerase chain reaction analysis detected that ARG levels in the bell pepper fruits significantly decreased to 10(-10) copies/16S copies, indicating limited risk of ARGs transferring along the food chain. Furthermore, the restoration of soil microbial biological function suggests that calcined eggshell is an environmentally friendly amendment to control the dissemination of soil ARB/ARGs in the soil-vegetable system.

  19. Antimicrobial Susceptibility of Bordetella bronchiseptica Isolates from Swine and Companion Animals and Detection of Resistance Genes.

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    Sandra Prüller

    Full Text Available Bordetella bronchiseptica causes infections of the respiratory tract in swine and other mammals and is a precursor for secondary infections with Pasteurella multocida. Treatment of B. bronchiseptica infections is conducted primarily with antimicrobial agents. Therefore it is essential to get an overview of the susceptibility status of these bacteria. The aim of this study was to comparatively analyse broth microdilution susceptibility testing according to CLSI recommendations with an incubation time of 16 to 20 hours and a longer incubation time of 24 hours, as recently proposed to obtain more homogenous MICs. Susceptibility testing against a panel of 22 antimicrobial agents and two fixed combinations was performed with 107 porcine isolates from different farms and regions in Germany and 43 isolates obtained from companion animals in Germany and other European countries. Isolates with increased MICs were investigated by PCR assays for the presence of resistance genes. For ampicillin, all 107 porcine isolates were classified as resistant, whereas only a single isolate was resistant to florfenicol. All isolates obtained from companion animals showed elevated MICs for β-lactam antibiotics and demonstrated an overall low susceptibility to cephalosporines. Extension of the incubation time resulted in 1-2 dilution steps higher MIC50 values of porcine isolates for seven antimicrobial agents tested, while isolates from companion animals exhibited twofold higher MIC50/90 values only for tetracycline and cefotaxime. For three antimicrobial agents, lower MIC50 and MIC90 values were detected for both, porcine and companion animal isolates. Among the 150 isolates tested, the resistance genes blaBOR-1 (n = 147, blaOXA-2, (n = 4, strA and strB (n = 17, sul1 (n = 10, sul2 (n = 73, dfrA7 (n = 3 and tet(A (n = 8 were detected and a plasmid localisation was identified for several of the resistance genes.

  20. Organization of a resistance gene cluster linked to rhizomania resistance in sugar beet

    Science.gov (United States)

    Genetic resistance to rhizomania has been in use for over 40 years. Characterization of the molecular basis for susceptibility and resistance has proved challenging. Nucleotide-binding leucine-rich-repeat-containing (NB-LRR) genes have been implicated in numerous gene-for-gene resistance interaction...

  1. Virulence Genes and Antimicrobial Resistance in Escherichia coli from Cheese Made from Unpasteurized Milk in Brazil.

    Science.gov (United States)

    de Campos, Anna C L P; Puño-Sarmiento, Juan J; Medeiros, Leonardo P; Gazal, Luís E S; Maluta, Renato Pariz; Navarro, Armando; Kobayashi, Renata K T; Fagan, Eder P; Nakazato, Gerson

    2018-02-01

    Cow raw milk cheese is widely eaten in Brazil. These products may be contaminated with pathogenic bacteria. In this work, we investigated the presence of Escherichia coli in raw milk cheese from different States in Brazil. From 147 "Minas" cheese samples, 28 cheeses were positive for E. coli. Among 39 E. coli isolates of the cheeses, one was positive for eae and negative for bpfA and efa1/lifA using PCR, and so was classified as atypical Enteropathogenic E. coli (aEPEC). Two other isolates were positive for extraintestinal pathogenic E. coli (ExPEC) genes. The aEPEC isolate belongs to serogroup O127 and was classified in A phylogenetic group, and ExPEC isolates were found in O73:H12 (EC-2 strain) and O64474:H8 (EC-9 strain) serotype. This ExPEC belongs to A and C phylogenetic group, respectively. Most of E. coli strains belonged to Clermont phylogenetic groups A (28.2%), C, and E (23.1%). Six strains (15.4%) of E. coli were positive for group B1 and two (5.1%) for B2. E. coli isolates presented an aggregative (46.0%) and diffuse (12.6%) adherence pattern to HeLa cells, and the other isolates did not show adhesion (41.4%). Four E. coli isolates (10.3%) were shown to produce moderate biofilm. The antimicrobial resistance rate was tetracycline (25.6%), followed by ampicillin (17.9%), cefoxitin (7.7%), nalidixic acid (5.1%), and amoxicillin-clavulanic acid (2.6%). One strain was resistant to three antimicrobials (tetracycline, ampicillin, and nalidixic acid). The presence of these microorganisms, the O127 strain, and a new serogroup in Brazil is a potential risk for public health.

  2. Modeling the fate of antibiotic resistance genes and class 1 integrons during thermophilic anaerobic digestion of municipal wastewater solids.

    Science.gov (United States)

    Burch, Tucker R; Sadowsky, Michael J; LaPara, Timothy M

    2015-10-19

    This study investigated the use of thermophilic anaerobic digestion for removing antibiotic resistance genes (ARGs) from residual municipal wastewater solids. Four laboratory-scale anaerobic digesters were operated in 8-day batch cycles at temperatures of 40, 56, 60, and 63 °C. Two tetracycline resistance genes (tet(W) and tet(X)), a fluoroquinolone resistance gene (qnrA), the integrase gene of class 1 integrons (intI1), 16S rRNA genes of all Bacteria, and 16S rRNA genes of methanogens were quantified using real-time quantitative PCR. ARG and intI1 quantities decreased at all temperatures and were described well by a modified form of the Collins-Selleck disinfection kinetic model. The magnitudes of Collins-Selleck kinetic parameters were significantly greater at thermophilic temperatures compared to 40 °C, but few statistically significant differences were observed among these parameters for the thermophilic anaerobic digesters. This model allows for the direct comparison of different operating conditions (e.g., temperature) on anaerobic digestion performance in mitigating the quantity of ARGs in wastewater solids and could be used to design full-scale anaerobic digesters to specifically treat for ARGs as a "pollutant" of concern.

  3. Antibiotic resistance genes persist longer in soils with subsurface banded poultry litter

    Science.gov (United States)

    The objective of this study was to determine the concentration of AR genes for sulfonamide (sulI), tetracycline (tetW), streptomycin (strpB) and for the class one integrase (intI1) gene in soils with subsurface banded PL. Field scale plots were established with triplicate treatments of either no fer...

  4. Resistance patterns, ESBL genes, and genetic relatedness of Escherichia coli from dogs and owners.

    Science.gov (United States)

    Carvalho, A C; Barbosa, A V; Arais, L R; Ribeiro, P F; Carneiro, V C; Cerqueira, A M F

    2016-01-01

    Antimicrobial resistance in Escherichia coli isolated from pet dogs can be considered a potential threat of infection for the human population. Our objective was to characterize the resistance pattern, extended spectrum beta-lactamase production and genetic relatedness of multiresistant E. coli strains isolated from dogs (n=134), their owners (n=134), and humans who claim to have no contact with dogs (n=44, control), searching for sharing of strains. The strains were assessed for their genetic relatedness by phylogenetic grouping and pulsed-field gel electrophoresis. Multiresistant E. coli strains were isolated from 42 (31.3%) fecal samples from pairs of dogs and owners, totaling 84 isolates, and from 19 (43.1%) control group subjects. The strains showed high levels of resistance to ampicillin, streptomycin, tetracycline, trimethoprim and sulfamethoxazole regardless of host species or group of origin. The blaTEM, blaCTX-M, and blaSHV genes were detected in similar proportions in all groups. All isolates positive for bla genes were ESBL producers. The phylogenetic group A was the most prevalent, irrespective of the host species. None of the strains belonging to the B2 group contained bla genes. Similar resistance patterns were found for strains from dogs, owners and controls; furthermore, identical PFGE profiles were detected in four (9.5%) isolate pairs from dogs and owners, denoting the sharing of strains. Pet dogs were shown to be a potential household source of multiresistant E. coli strains. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  5. Housefly Larva Vermicomposting Efficiently Attenuates Antibiotic Resistance Genes in Swine Manure, with Concomitant Bacterial Population Changes

    Science.gov (United States)

    Wang, Hang; Li, Hongyi; Gilbert, Jack A.; Li, Haibo; Wu, Longhua; Liu, Meng; Wang, Liling; Zhou, Qiansheng; Yuan, Junxiang

    2015-01-01

    Manure from swine treated with antimicrobials as feed additives is a major source for the expansion of the antibiotic resistance gene (ARG) reservoir in the environment. Vermicomposting via housefly larvae (Musca domestica) can be efficiently used to treat manure and regenerate biofertilizer, but few studies have investigated its effect on ARG attenuation. Here, we tracked the abundances of 9 ARGs and the composition and structure of the bacterial communities in manure samples across 6 days of full-scale manure vermicomposting. On day 6, the abundances of genes encoding tetracycline resistance [tet(M), tet(O), tet(Q), and tet(W)] were reduced (P vermicomposting, accompanied by a 100 times increase in the relative abundance of Flavobacteriaceae spp. Variations in the abundances of ARGs were correlated with the changing microbial community structure and the relative abundances of the family Ruminococcaceae, class Bacilli, or phylum Proteobacteria. Vermicomposting, as a waste management practice, can reduce the overall abundance of ARGs. More research is warranted to assess the use of this waste management practice as a measure to attenuate the dissemination of antimicrobial residues and ARGs from livestock production before vermicompost can be safely used as biofertilizer in agroecosystems. PMID:26296728

  6. Viromes As Genetic Reservoir for the Microbial Communities in Aquatic Environments: A Focus on Antimicrobial-Resistance Genes

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    Stefano Colombo

    2017-06-01

    Full Text Available Despite studies of viromes isolated from aquatic environments are becoming increasingly frequent, most of them are limited to the characterization of viral taxonomy. Bacterial reads in viromes are abundant but the extent to which this genetic material is playing a role in the ecology of aquatic microbiology remains unclear. To this aim, we developed of a useful approach for the characterization of viral and microbial communities of aquatic environments with a particular focus on the identification of microbial genes harbored in the viromes. Virus-like particles were isolated from water samples collected across the Lambro River, from the spring to the high urbanized Milan area. The derived viromes were analyzed by shotgun metagenomic sequencing looking for the presence, relative abundance of bacterial genes with particular focus on those genes involved in antimicrobial resistance mechanisms. Antibiotic and heavy metal resistance genes have been identified in all virome samples together with a high abundance of reads assigned to cellular processes and signaling. Virome data compared to those identified in the microbiome isolated from the same sample revealed differences in terms of functional categories and their relative abundance. To verify the role of aquatic viral population in bacterial gene transfer, water-based mesocosms were perturbed or not perturbed with a low dose of tetracycline. The results obtained by qPCR assays revealed variation in abundance of tet genes in the virome and microbiome highlighting a relevant role of viral populations in microbial gene mobilization.

  7. [Preliminary studies on the occurrence of antibiotic resistance genes in typical aquaculture area of the Pearl River Estuary].

    Science.gov (United States)

    Liang, Xi-Mei; Nie, Xiang-Ping; Shi, Zhen

    2013-10-01

    Traditional and quantitative PCR techniques were used to determine the occurrence and quantities of ARGs, including three types of genes resistant to sulfonamide, seven for tetracycline resistance and one for quinolone resistance, as well as one integron gene in typical aquaculture of the Pearl River Estuary. The results showed that all genes except for tetW were detectable in the aquaculture environment, and sull, sul2 and int1 were the most frequently detected genes (detectable percentage, 100% ). Relative abundances of ARGs increased with the prolongation of rearing time under the same aquaculture pattern, suggesting a cumulative effect. Moreover, the occurrences of ARGs in the ponds were different with different aquaculture patterns, indicating that the aquaculture pattern might play an important role in the abundances and distributions of ARGs. Relative abundances of intl, as a horizontal mobile genetic element, were significantly correlated to the levels of sull and the total ARGs (P aquaculture substantially increased the abundances of ARGs probably owning to the induction of horizontal gene transfer of ARGs among bacteria.

  8. Characterization of tetracycline modifying enzymes using a sensitive in vivo reporter system

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    Yu Zhou

    2010-09-01

    Full Text Available Abstract Background Increasing our understanding of antibiotic resistance mechanisms is critical. To enable progress in this area, methods to rapidly identify and characterize antibiotic resistance conferring enzymes are required. Results We have constructed a sensitive reporter system in Escherichia coli that can be used to detect and characterize the activity of enzymes that act upon the antibiotic, tetracycline and its derivatives. In this system, expression of the lux operon is regulated by the tetracycline repressor, TetR, which is expressed from the same plasmid under the control of an arabinose-inducible promoter. Addition of very low concentrations of tetracycline derivatives, well below growth inhibitory concentrations, resulted in luminescence production as a result of expression of the lux genes carried by the reporter plasmid. Introduction of another plasmid into this system expressing TetX, a tetracycline-inactivating enzyme, caused a marked loss in luminescence due to enzyme-mediated reduction in the intracellular Tc concentration. Data generated for the TetX enzyme using the reporter system could be effectively fit with the known Km and kcat values, demonstrating the usefulness of this system for quantitative analyses. Conclusion Since members of the TetR family of repressors regulate enzymes and pumps acting upon almost every known antibiotic and a wide range of other small molecules, reporter systems with the same design as presented here, but employing heterologous TetR-related proteins, could be developed to measure enzymatic activities against a wide range of antibiotics and other compounds. Thus, the assay described here has far-reaching applicability and could be adapted for high-throughput applications.

  9. No evidential correlation between veterinary antibiotic degradation ability and resistance genes in microorganisms during the biodegradation of doxycycline.

    Science.gov (United States)

    Wen, Xin; Wang, Yan; Zou, Yongde; Ma, Baohua; Wu, Yinbao

    2018-01-01

    Biodegradation of antibiotic residues in the environment by microorganisms may lead to the generation of antibiotic resistance genes (ARGs), which are of great concern to human health. The aim of this study was to determine whether there is a relationship between the ability to degrade antibiotic doxycycline (DOX) and the development of resistance genes in microorganisms. We isolated and identified ten bacterial strains from a vegetable field that had received long-term manure application as fertilizer and were capable of surviving in a series of DOX concentrations (25, 50, 80, and 100mg/L). Our results showed no evidential correlation between DOX degradation ability and the development of resistance genes among the isolated microorganisms that had high DOX degradation capability (P > 0.05). This was based on the fact that Escherichia sp. and Candida sp. were the most efficient bacterial strains to degrade DOX (92.52% and 91.63%, respectively), but their tetracycline resistance genes showed a relatively low risk of antibiotic resistance in a 7-day experiment. Moreover, the tetM of the ribosomal protection protein genes carried by these two preponderant bacteria was five-fold higher than that carried by other isolates (P < 0.05). Pearson correlations between the Ct/C0 of DOX and tet resistance genes of three isolates, except for Escherichia sp. and Candida sp., showed remarkable negative correlations (P < 0.05), mainly because tetG markedly increased during the DOX degradation process. Our results concluded that the biodegradation of antibiotic residues may not necessarily lead to the development of ARGs in the environment. In addition, the two bacteria that we isolated, namely, Escherichia sp. and Candida sp., are potential candidates for the engineering of environmentally friendly bacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Effect of silver nanoparticles and antibiotics on antibiotic resistance genes in anaerobic digestion.

    Science.gov (United States)

    Miller, Jennifer H; Novak, John T; Knocke, William R; Young, Katherine; Hong, Yanjuan; Vikesland, Peter J; Hull, Matthew S; Pruden, Amy

    2013-05-01

    Water resource recovery facilities have been described as creating breeding ground conditions for the selection, transfer, and dissemination of antibiotic resistance genes (ARGs) among various bacteria. The objective of this study was to determine the effect of direct addition of antibiotic and silver nanoparticles (Ag NPs, or nanosilver) on the occurrence of ARGs in thermophilic anaerobic digesters. Test thermophilic digesters were amended with environmentally-relevant concentrations of Ag NP (0.01, 0.1, and 1.0 mg-Ag/L; corresponding to approximately 0.7, 7.0, and 70 mg-Ag/kg total solids) and sulfamethoxazole (SMX) that span susceptible to resistant classifications (1, 5, and 50 mg/L) as potential selection pressures for ARGs. Tetracycline (tet(O), tet(W)) and sulfonamide (sulI, sulII) ARGs and the integrase enzyme gene (intI1) associated with Class 1 integrons were measured in raw sludge, test thermophilic digesters, a control thermophilic digester, and a control mesophilic digester. There was no apparent effect of Ag NPs on thermophilic anaerobic digester performance. The maximum SMX addition (50 mg/L) resulted in accumulation of volatile fatty acids and low pH, alkalinity, and volatile solids reduction. There was no significant difference between ARG gene copy numbers (absolute or normalized to 16S rRNA genes) in amended thermophilic digesters and the control thermophilic digester. Antibiotic resistance gene copy numbers in digested sludge ranged from 10(3) to 10(6) copies per microL (approximately 8 x10(1) to 8 x 10(4) copies per microg) of sludge as result of a 1-log reduction of ARGs (2-log reduction for intI1). Quantities of the five ARGs in raw sludge ranged from 10(4) to 10(8) copies per microL (approximately 4 x 10(2) to 4 x 10(6) per microg) of sludge. Test and control thermophilic digesters (53 degrees C, 12-day solids retention time [SRT]) consistently reduced but did not eliminate levels of all analyzed genes. The mesophilic digester (37 degrees C

  11. Determination of resistance and virulence genes in Enterococcus faecalis and E. faecium strains isolated from poultry and their genotypic characterization by ADSRRS-fingerprinting.

    Science.gov (United States)

    Nowakiewicz, A; Ziólkowska, G; Troscianczyk, A; Zieba, P; Gnat, S

    2017-04-01

    The aim of this study was to determine the antimicrobial resistance of E. faecalis and E. faecium strains isolated from poultry and to carry out genotypic characterization thereof with the ADSRRS-fingerprinting method (amplification of DNA fragments surrounding rare restriction sites) and analysis of the genetic relatedness between the isolates with different resistance and virulence determinants. Samples were collected from 70 4-week-old chickens and tested for Enterococcus. Minimum inhibitory concentrations of 11 antimicrobials were determined using the broth microdilution method. Detection of antibiotic resistance and virulence genes was performed using PCR, and molecular analysis was carried out using the ADSRRS-fingerprinting method. The highest percentage of strains was resistant to tetracycline (60.5%) and erythromycin (54.4%), and a large number exhibited high-level resistance to both kanamycin (42.1%) and streptomycin (34.2%). Among 8 genes encoding AME, the tested strains showed mainly the presence of [aph(3΄)-IIIa], [ant(6)-Ia], [aac(6΄)-Ie-aph(2΄΄)-Ia], and [ant(9)-Ia] genes. Phenotypic resistance to erythromycin was encoded in 98.4% strains by the ermB gene. Genotypic resistance to tetracycline in E. faecium was associated with the presence of tetM and tetL (respectively, in 95.5 and 57.7% of the isolates); in contrast, E. faecalis strains were characterized mainly by the presence of tetO (83.3%). The virulence profile was homogenous for all E. faecium strains and included only efaAfm and ccf genes. All E. faecalis strains exhibited efaAfs, gelE, and genes encoding sex pheromones. The strains tested exhibited 34 genotypic profiles. Comparative analysis of phenotypic and genotypic resistance and virulence profiles and confrontation thereof with the genotypes of the strains tested showed that strains assigned to a particular genotype have an identical phenotypic resistance profile and a panel of resistance and virulence genes. The results of this

  12. Horizontal gene transfer and antibiotic resistance plasmids in multi-drug resistant Salmonella enterica serovars

    Science.gov (United States)

    Antibiotic resistant foodborne pathogens pose serious public health concerns and increase the burden of disease treatment. Antibiotic resistance genes can reside on the bacterial chromosome or on other self-replicating DNA molecules such as plasmids. The resistance genes/DNA can be transferred int...

  13. Development of antibiotic resistance genes in microbial communities during long-term operation of anaerobic reactors in the treatment of pharmaceutical wastewater.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2015-10-15

    Biological treatment processes offer the ideal conditions in which a high diversity of microorganisms can grow and develop. The wastewater produced during these processes is contaminated with antibiotics and, as such, they provide the ideal setting for the acquisition and proliferation of antibiotic resistance genes (ARGs). This research investigated the occurrence and variation in the ARGs found during the one-year operation of the anaerobic sequencing batch reactors (SBRs) used to treat pharmaceutical wastewater that contained combinations of sulfamethoxazole-tetracycline-erythromycin (STE) and sulfamethoxazole-tetracycline (ST). The existence of eighteen ARGs encoding resistance to sulfamethoxazole (sul1, sul2, sul3), erythromycin (ermA, ermF, ermB, msrA, ereA), tetracycline (tetA, tetB, tetC, tetD, tetE, tetM, tetS, tetQ, tetW, tetX) and class Ι integron gene (intΙ 1) in the STE and ST reactors was investigated by quantitative real-time PCR. Due to the limited availability of primers to detect ARGs, Illumina sequencing was also performed on the sludge and effluent of the STE and ST reactors. Although there was good reactor performance in the SBRs, which corresponds to min 80% COD removal efficiency, tetA, tetB, sul1, sul2 and ermB genes were among those ARGs detected in the effluent from STE and ST reactors. A comparison of the ARGs acquired from the STE and ST reactors revealed that the effluent from the STE reactor had a higher number of ARGs than that from the ST reactor; this could be due to the synergistic effects of erythromycin. According to the expression of genes results, microorganisms achieve tetracycline and erythromycin resistance through a combination of three mechanisms: efflux pumping protein, modification of the antibiotic target and modifying enzymes. There was also a significant association between the presence of the class 1 integron and sulfamethoxazole resistance genes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Detection of linezolid resistance due to the optrA gene in Enterococcus faecalis from poultry meat from the American continent (Colombia).

    Science.gov (United States)

    Cavaco, L M; Bernal, J F; Zankari, E; Léon, M; Hendriksen, R S; Perez-Gutierrez, E; Aarestrup, F M; Donado-Godoy, P

    2017-03-01

    Three Enterococcus isolates obtained from retail chicken collected in 2010-11 as part of the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS) showed reduced susceptibility towards linezolid (MIC 8 mg/L). This study aimed at characterizing the isolates resistant to linezolid and detecting the resistance mechanism. Strains were analysed in 2011-12 without successful detection of the resistance mechanism. All isolates were found negative for the cfr gene and no 23S rRNA mutations were detected. In 2016, with the novel resistance gene optrA being described, the WGS data were re-analysed using in silico genomic tools for confirmation of species, detection of virulence and resistance genes, MLST and SNP analyses and comparison of the genetic environment with the previously published plasmid pE349. : Three Enterococcus faecalis isolates were found positive for the optrA gene encoding resistance to linezolid and phenicols. Additional screening of 37 enterococci strains from the same study did not detect any further positives. Typing showed that two of the isolates belong to ST59, while the last belongs to ST489. All isolates carry genes encoding resistance to macrolide-lincosamide-streptogramin B, tetracycline and phenicols. In addition, the ST489 isolate also carries genes conferring aminoglycoside resistance and is resistant to quinolones, but no plasmid-mediated gene was detected. The optrA gene regions of the three plasmids showed high similarity to the originally reported optrA -carrying plasmid pE349. To the best of our knowledge, this is the first description of the optrA gene in E. faecalis isolated from poultry meat in the Americas.

  15. Synthetic tetracycline-inducible regulatory networks: computer-aided design of dynamic phenotypes

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    Kaznessis Yiannis N

    2007-01-01

    Full Text Available Abstract Background Tightly regulated gene networks, precisely controlling the expression of protein molecules, have received considerable interest by the biomedical community due to their promising applications. Among the most well studied inducible transcription systems are the tetracycline regulatory expression systems based on the tetracycline resistance operon of Escherichia coli, Tet-Off (tTA and Tet-On (rtTA. Despite their initial success and improved designs, limitations still persist, such as low inducer sensitivity. Instead of looking at these networks statically, and simply changing or mutating the promoter and operator regions with trial and error, a systematic investigation of the dynamic behavior of the network can result in rational design of regulatory gene expression systems. Sophisticated algorithms can accurately capture the dynamical behavior of gene networks. With computer aided design, we aim to improve the synthesis of regulatory networks and propose new designs that enable tighter control of expression. Results In this paper we engineer novel networks by recombining existing genes or part of genes. We synthesize four novel regulatory networks based on the Tet-Off and Tet-On systems. We model all the known individual biomolecular interactions involved in transcription, translation, regulation and induction. With multiple time-scale stochastic-discrete and stochastic-continuous models we accurately capture the transient and steady state dynamics of these networks. Important biomolecular interactions are identified and the strength of the interactions engineered to satisfy design criteria. A set of clear design rules is developed and appropriate mutants of regulatory proteins and operator sites are proposed. Conclusion The complexity of biomolecular interactions is accurately captured through computer simulations. Computer simulations allow us to look into the molecular level, portray the dynamic behavior of gene regulatory

  16. Detection of Methicillin-Resistance Gene (mec-A in Staphylococcus aureus Strains by PCR and Determination of Antibiotic Sensitivity

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    A.R. Zamani

    2007-10-01

    Full Text Available Introduction & Objective: Methicillin–Resistant Staphylococcus aureus (MRSA is one of the most important causes of hospital infections worldwide. Treatment of these infections has become more difficult because of resistance to methicillin/oxacillin and other antibiotics. The aim of this study was to determine the incidence of MRSA infections in hospitals affiliated to Hamadan University of Medical Sciences.Materials & Methods: Seventy S. aureus clinical strains were isolated from patients from June, 2005 to June, 2006 and examined by conventional microbiological tests and PCR, respectively. Then, the antibiotic susceptibility to methicillin/oxacillin and other antibiotic were performed by Disk Diffusion Agar (DDA.Results: The results of this study showed that Methicillin resistance gene was detected in 35 (50% and 22 (31.4% cases by PCR and DDA, respectively. The results of antibiotic sensitivity assays also showed there was high resistance in MRSA strains to Penicillin (100%, Cloxacillin (91.4%, Tetracycline (74.2%, Cotrimoxazole (68.6% Erythromycin (68.5% and Ceftazidim (51.4%. The strains of Methicillin-Sensitive Staphylococcus aureus (MSSA showed high sensitivity results to antibiotic used, except penicillin, which all of the isolates were penicillin resistance.Conclusion: As a conclusion, the resistant to methicillin/oxacillin in Hamadan hospitals has reached to 50% and they show multi-drug resistant.

  17. Involvement of aph(3‘-IIa in the formation of mosaic aminoglycoside resistance genes in natural environments

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    Markus eWoegerbauer

    2015-05-01

    Full Text Available Intragenic recombination leading to mosaic gene formation is known to alter resistance profiles for particular genes and bacterial species. Few studies have examined to what extent aminoglycoside resistance genes undergo intragenic recombination.We screened the GenBank database for mosaic gene formation in homologs of the aph(3’-IIa (nptII gene. APH(3’-IIa inactivates important aminoglycoside antibiotics. The gene is widely used as a selectable marker in biotechnology and enters the environment via laboratory discharges and the release of transgenic organisms. Such releases may provide opportunities for recombination in competent environmental bacteria.The retrieved GenBank sequences were grouped in 3 datasets comprising river water samples, duck pathogens and full-length variants from various bacterial genomes and plasmids. Analysis for recombination in these datasets was performed with the Recombination Detection Program, RDP4, and the Genetic Algorithm for Recombination Detection, GARD.From a total of 89 homologous sequences, 83% showed 99% - 100% sequence identity with aph(3’-IIa originally described as part of transposon Tn5. Fifty one were unique sequence variants eligible for recombination analysis. Only a single recombination event was identified with high confidence and indicated the involvement of aph(3’-IIa in the formation of a mosaic gene located on a plasmid of environmental origin in the multi-resistant isolate Pseudomonas aeruginosa PA96. The available data suggest that aph(3’-IIa is not an archetypical mosaic gene as the divergence between the described sequence variants and the number of detectable recombination events is low. This is in contrast to the numerous mosaic alleles reported for certain penicillin or tetracycline resistance determinants.

  18. The tomato I-3 gene: a novel gene for resistance to Fusarium wilt disease.

    Science.gov (United States)

    Catanzariti, Ann-Maree; Lim, Ginny T T; Jones, David A

    2015-07-01

    Plant resistance proteins provide race-specific immunity through the recognition of pathogen effectors. The resistance genes I, I-2 and I-3 have been incorporated into cultivated tomato (Solanum lycopersicum) from wild tomato species to confer resistance against Fusarium oxysporum f. sp. lycopersici (Fol) races 1, 2 and 3, respectively. Although the Fol effectors corresponding to these resistance genes have all been identified, only the I-2 resistance gene has been isolated from tomato. To isolate the I-3 resistance gene, we employed a map-based cloning approach and used transgenic complementation to test candidate genes for resistance to Fol race 3. Here, we describe the fine mapping and sequencing of genes at the I-3 locus, which revealed a family of S-receptor-like kinase (SRLK) genes. Transgenic tomato lines were generated with three of these SRLK genes and one was found to confer Avr3-dependent resistance to Fol race 3, confirming it to be I-3. The finding that I-3 encodes an SRLK reveals a new pathway for Fol resistance and a new class of resistance genes, of which Pi-d2 from rice is also a member. The identification of I-3 also allows the investigation of the complex effector-resistance protein interaction involving Avr1-mediated suppression of I-2- and I-3-dependent resistance in tomato. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  19. Polymorphisms in Plasmodium falciparum chloroquine resistance transporter and multidrug resistance 1 genes

    DEFF Research Database (Denmark)

    Venkatesan, Meera; Gadalla, Nahla B; Stepniewska, Kasia

    2014-01-01

    Adequate clinical and parasitologic cure by artemisinin combination therapies relies on the artemisinin component and the partner drug. Polymorphisms in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multidrug resistance 1 (pfmdr1) genes are associated...

  20. Seasonal variation and removal efficiency of antibiotic resistance genes during wastewater treatment of swine farms.

    Science.gov (United States)

    Sui, Qianwen; Zhang, Junya; Tong, Juan; Chen, Meixue; Wei, Yuansong

    2017-04-01

    The seasonal variation and removal efficiency of antibiotic resistance genes (ARGs), including tetracycline resistance genes (tetG, tetM, and tetX) and macrolide (ermB, ermF, ereA, and mefA), were investigated in two typical swine wastewater treatment systems in both winter and summer. ARGs, class 1 integron gene, and 16S rRNA gene were quantified using real-time polymerase chain reaction assays. There was a 0.31-3.52 log variation in ARGs in raw swine wastewater, and the abundance of ARGs in winter was higher than in summer. tetM, tetX, ermB, ermF, and mefA were highly abundant. The abundance of ARGs was effectively reduced by most individual treatment process and the removal efficiencies of ARGs were higher in winter than in summer. However, when examining relative abundance, the fate of ARGs was quite variable. Anaerobic digestion reduced the relative abundance of tetX, ermB, ermF, and mefA, while lagoon treatment decreased tetM, ermB, ermF, and mefA. Sequencing batch reactor (SBR) decreased tetM, ermB, and ermF, but biofilters and wetlands did not display consistent removal efficiency on ARGs in two sampling seasons. As far as the entire treatment system is concerned, ermB and mefA were effectively reduced in both winter and summer in both total and relative abundance. The relative abundances of tetG and ereA were significantly correlated with intI1 (p wastewater treatment. This may pose a great threat to public health.

  1. Reclaimed water as a reservoir of antibiotic resistance genes: distribution system and irrigation implications

    Directory of Open Access Journals (Sweden)

    Nicole L Fahrenfeld

    2013-05-01

    Full Text Available Treated wastewater is increasingly being reused to achieve sustainable water management in arid regions. The objective of this study was to quantify the distribution of antibiotic resistance genes (ARGs in recycled water, particularly after it has passed through the distribution system, and to consider point-of-use implications for soil irrigation. Three separate reclaimed wastewater distribution systems in the western U.S. were examined. Quantitative polymerase chain reaction (qPCR was used to quantify ARGs corresponding to resistance to sulfonamides (sul1, sul2, macrolides (ermF, tetracycline (tet(A, tet(O, glycopeptides (vanA, and methicillin (mecA, in addition to genes present in waterborne pathogens Legionella pneumophila (Lmip, Escherichia coli (gadAB, and Pseudomonas aeruginosa (ecfx, gyrB. In a parallel lab study, the effect of irrigating an agricultural soil with secondary, chlorinated, or dechlorinated wastewater effluent was examined in batch microcosms. A broader range of ARGs were detected after the reclaimed water passed through the distribution systems, highlighting the importance of considering bacterial re-growth and the overall water quality at the point of use. Screening for pathogens with qPCR indicated presence of Lmip and gadAB genes, but not ecfx or gyrB. In the lab study, chlorination was observed to reduce 16S rRNA and sul2 gene copies in the wastewater effluent, while dechlorination had no apparent effect. ARGs levels did not change with time in soil slurries incubated after a single irrigation event with any of the effluents. However, when irrigated repeatedly with secondary wastewater effluent (not chlorinated or dechlorinated, elevated levels of sul1 and sul2 were observed. This study suggests that reclaimed water may be an important reservoir of ARGs, especially at the point of use, and that attention should be directed towards the fate of ARGs in irrigation water and the implications for human health.

  2. Molecular detection of disease resistance genes to powdery mildew ...

    African Journals Online (AJOL)

    A study was conducted to detect the presence of disease resistance genes to infection of wheat powdery mildew (Blumeria graminis f. sp. tritici) in selected wheat cultivars from China using molecular markers. Genomic DNA of sixty cultivars was extracted and tested for the presence of selected prominent resistance genes to ...

  3. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    PUNEET INDER TOOR

    Abstract. A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcross- recombinant inbred line (BC-RIL) population derived from the cross of a ...

  4. Widespread plasmid resistance genes among Proteus species in ...

    African Journals Online (AJOL)

    Widespread plasmid resistance genes among Proteus species in diabetic wounds of patients in the Ahmadu Bello university teaching hospital (ABUTH) Zaria. ... African Journal of Biotechnology ... Plasmids have been known to play a major role in the dissemination of antibiotics resistance genes in a microbial population.

  5. Genome scanning for identification of resistance gene analogs ...

    African Journals Online (AJOL)

    Disease resistance in plants is a desirable economic trait. Many disease resistance genes from various plants have been cloned so far. The gene products of some of these can be distinguished by the presence of an N terminal nucleotide binding site and a C-terminal stretch of leucine-rich repeats. Oligonucleotides already ...

  6. Gene pyramiding as a Bt resistance management strategy: How ...

    African Journals Online (AJOL)

    Questions have been raised on the sustainability of gene pyramiding since the use of insecticide mixtures has shown that cross resistance and/or multiple resistance can render such strategies to be less effective in the long term. Current theoretical and practical evidence in insect population genetics suggest that gene ...

  7. Removal of selected PPCPs, EDCs, and antibiotic resistance genes in landfill leachate by a full-scale constructed wetlands system.

    Science.gov (United States)

    Yi, Xinzhu; Tran, Ngoc Han; Yin, Tingru; He, Yiliang; Gin, Karina Yew-Hoong

    2017-09-15

    Landfill leachate could be a significant source of emerging contaminants (ECs) and antibiotic resistance genes (ARGs) into the environment. This study provides the first information on the occurrence of selected ECs and ARGs in raw leachate from 16-year old closed landfill site in Singapore. Among the investigated ECs, acetaminophen (ACT), bisphenol A (BPA), clofibric acid (CA), caffeine (CF), crotamiton (CTMT), diclofenac (DCF), N,N-diethyl-m-toluamide (DEET), gemfibrozil (GFZ), lincomycin (LIN), salicylic acid (SA), and sulfamethazine (SMZ) were the most frequently detected compounds in raw landfill leachate. The concentrations of detected ECs in raw landfill leachate varied significantly, from below quantification limit to 473,977 ng/L, depending on the compound. In this study, Class I integron (intl1) gene and ten ARGs were detected in raw landfill leachate. Sulfonamide resistance (sul1, sul2, and dfrA), aminoglycoside resistance (aac6), tetracycline resistance (tetO), quinolone resistance (qnrA), and intl1 were ubiquitously present in raw landfill leachate. Other resistance genes, such as beta-lactam resistance (blaNMD1, blaKPC, and blaCTX) and macrolide-lincosamide resistance (ermB) were also detected, detection frequency of 90%) in the investigated hybrid CW system. This hybrid CW system was also found to be effective in the reduction of several ARGs (intl1, sul1, sul2, and qnrA). Aeration lagoons and reed beds appeared to be the most important treatment units of the hybrid CW for removing the majority of ECs from the leachate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Characterization of Metagenomes in Urban Aquatic Compartments Reveals High Prevalence of Clinically Relevant Antibiotic Resistance Genes in Wastewaters

    Directory of Open Access Journals (Sweden)

    Charmaine Ng

    2017-11-01

    Full Text Available The dissemination of antimicrobial resistance (AMR is an escalating problem and a threat to public health. Comparative metagenomics was used to investigate the occurrence of antibiotic resistant genes (ARGs in wastewater and urban surface water environments in Singapore. Hospital and municipal wastewater (n = 6 were found to have higher diversity and average abundance of ARGs (303 ARG subtypes, 197,816 x/Gb compared to treated wastewater effluent (n = 2, 58 ARG subtypes, 2,692 x/Gb and surface water (n = 5, 35 subtypes, 7,985 x/Gb. A cluster analysis showed that the taxonomic composition of wastewaters was highly similar and had a bacterial community composition enriched in gut bacteria (Bacteroides, Faecalibacterium, Bifidobacterium, Blautia, Roseburia, Ruminococcus, the Enterobacteriaceae group (Klebsiella, Aeromonas, Enterobacter and opportunistic pathogens (Prevotella, Comamonas, Neisseria. Wastewater, treated effluents and surface waters had a shared resistome of 21 ARGs encoding multidrug resistant efflux pumps or resistance to aminoglycoside, macrolide-lincosamide-streptogramins (MLS, quinolones, sulfonamide, and tetracycline resistance which suggests that these genes are wide spread across different environments. Wastewater had a distinctively higher average abundance of clinically relevant, class A beta-lactamase resistant genes (i.e., blaKPC, blaCTX-M, blaSHV, blaTEM. The wastewaters from clinical isolation wards, in particular, had a exceedingly high levels of blaKPC-2 genes (142,200 x/Gb, encoding for carbapenem resistance. Assembled scaffolds (16 and 30 kbp from isolation ward wastewater samples indicated this gene was located on a Tn3-based transposon (Tn4401, a mobilization element found in Klebsiella pneumonia plasmids. In the longer scaffold, transposable elements were flanked by a toxin–antitoxin (TA system and other metal resistant genes that likely increase the persistence, fitness and propagation of the plasmid in the

  9. Characterization of Metagenomes in Urban Aquatic Compartments Reveals High Prevalence of Clinically Relevant Antibiotic Resistance Genes in Wastewaters.

    Science.gov (United States)

    Ng, Charmaine; Tay, Martin; Tan, Boonfei; Le, Thai-Hoang; Haller, Laurence; Chen, Hongjie; Koh, Tse H; Barkham, Timothy M S; Gin, Karina Y-H

    2017-01-01

    The dissemination of antimicrobial resistance (AMR) is an escalating problem and a threat to public health. Comparative metagenomics was used to investigate the occurrence of antibiotic resistant genes (ARGs) in wastewater and urban surface water environments in Singapore. Hospital and municipal wastewater (n = 6) were found to have higher diversity and average abundance of ARGs (303 ARG subtypes, 197,816 x/Gb) compared to treated wastewater effluent (n = 2, 58 ARG subtypes, 2,692 x/Gb) and surface water (n = 5, 35 subtypes, 7,985 x/Gb). A cluster analysis showed that the taxonomic composition of wastewaters was highly similar and had a bacterial community composition enriched in gut bacteria (Bacteroides, Faecalibacterium, Bifidobacterium, Blautia, Roseburia, Ruminococcus), the Enterobacteriaceae group (Klebsiella, Aeromonas, Enterobacter) and opportunistic pathogens (Prevotella, Comamonas, Neisseria). Wastewater, treated effluents and surface waters had a shared resistome of 21 ARGs encoding multidrug resistant efflux pumps or resistance to aminoglycoside, macrolide-lincosamide-streptogramins (MLS), quinolones, sulfonamide, and tetracycline resistance which suggests that these genes are wide spread across different environments. Wastewater had a distinctively higher average abundance of clinically relevant, class A beta-lactamase resistant genes (i.e., blaKPC, blaCTX-M, blaSHV, blaTEM). The wastewaters from clinical isolation wards, in particular, had a exceedingly high levels of blaKPC-2 genes (142,200 x/Gb), encoding for carbapenem resistance. Assembled scaffolds (16 and 30 kbp) from isolation ward wastewater samples indicated this gene was located on a Tn3-based transposon (Tn4401), a mobilization element found in Klebsiella pneumonia plasmids. In the longer scaffold, transposable elements were flanked by a toxin-antitoxin (TA) system and other metal resistant genes that likely increase the persistence, fitness and propagation of the plasmid in the bacterial

  10. Emergence of a Clonal Lineage of Multidrug-Resistant ESBL-Producing Salmonella Infantis Transmitted from Broilers and Broiler Meat to Humans in Italy between 2011 and 2014

    DEFF Research Database (Denmark)

    Franco, Alessia; Leekitcharoenphon, Pimlapas; Feltrin, Fabiola

    2015-01-01

    . This megaplasmid carried the ESBL gene blaCTX-M-1, and additional genes [tet(A), sul1, dfrA1 and dfrA14] mediating cefotaxime, tetracycline, sulfonamide, and trimethoprim resistance. It also contained genes conferring enhanced colonization capability, virulence (fimbriae, yersiniabactin), resistance and fitness...

  11. Occurrence of antibiotic resistance genes in the fecal DNA of healthy omnivores, ovo-lacto vegetarians and vegans.

    Science.gov (United States)

    Milanović, Vesna; Osimani, Andrea; Aquilanti, Lucia; Tavoletti, Stefano; Garofalo, Cristiana; Polverigiani, Serena; Litta-Mulondo, Alice; Cocolin, Luca; Ferrocino, Ilario; Di Cagno, Raffaella; Turroni, Silvia; Lazzi, Camilla; Pellegrini, Nicoletta; Clementi, Francesca

    2017-09-01

    The effects of long-term omnivore, ovo-lacto vegetarian and vegan diets on the occurrence of 12 antibiotic resistance (AR) genes in the human gut were studied. The feces of 144 healthy volunteers recruited from Turin, Bari, Bologna, and Parma were screened for the occurrence of genes conferring resistance to tetracyclines, macrolide-lincosamide-streptogramin B, vancomycin, and β-lactams. Overall, erm(B), tet(W) and tet(M) were detected at the highest frequency. A low effect from the diet on the AR gene distribution emerged, with tet(K) and vanB occurring at a lower and higher frequency in vegans and omnivores, respectively. A correlation of the intake of eggs, milk from animal sources and cheese with an increased occurrence of tet(K) was observed, together with a higher incidence of vanB in consumers of eggs, poultry meat, fish and seafood. When the detection frequencies of AR genes in volunteers from Bari and the other sites were comparatively evaluated, a north-to-south gradient was observed, whereas no effect of sex or age was highlighted. Except for tet(K), a negligible three-factor interaction was seen. A high impact of the geographical location on AR gene distribution was seen in the cohort of subjects analyzed, irrespective of their dietary habits. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Sponge microbiota are a reservoir of functional antibiotic resistance genes

    Directory of Open Access Journals (Sweden)

    Dennis Versluis

    2016-11-01

    Full Text Available Wide application of antibiotics has contributed to the evolution of multi-drug resistant human pathogens, resulting in poorer treatment outcomes for infections. In the marine environment, seawater samples have been investigated as a resistance reservoir; however, no studies have methodically examined sponges as a reservoir of antibiotic resistance. Sponges could be important in this respect because they often contain diverse microbial communities that have the capacity to produce bioactive metabolites. Here, we applied functional metagenomics to study the presence and diversity of functional resistance genes in the sponges Aplysina aerophoba, Petrosia ficiformis and Corticium candelabrum. We obtained 37 insert sequences facilitating resistance to D-cycloserine (n=6, gentamicin (n=1, amikacin (n=7, trimethoprim (n=17, chloramphenicol (n=1, rifampicin (n=2 and ampicillin (n=3. Fifteen of 37 inserts harboured resistance genes that shared <90% amino acid identity with known gene products, whereas on 13 inserts no resistance gene could be identified with high confidence, in which case we predicted resistance to be mainly mediated by antibiotic efflux. One marine-specific ampicillin-resistance-conferring β-lactamase was identified in the genus Pseudovibrio with 41% global amino acid identity to the closest β-lactamase with demonstrated functionality, and subsequently classified into a new family termed PSV. Taken together, our results show that sponge microbiota host diverse and novel resistance genes that may be harnessed by phylogenetically distinct bacteria.

  13. Antibiotics, bacteria, and antibiotic resistance genes: aerial transport from cattle feed yards via particulate matter.

    Science.gov (United States)

    McEachran, Andrew D; Blackwell, Brett R; Hanson, J Delton; Wooten, Kimberly J; Mayer, Gregory D; Cox, Stephen B; Smith, Philip N

    2015-04-01

    Emergence and spread of antibiotic resistance has become a global health threat and is often linked with overuse and misuse of clinical and veterinary chemotherapeutic agents. Modern industrial-scale animal feeding operations rely extensively on veterinary pharmaceuticals, including antibiotics, to augment animal growth. Following excretion, antibiotics are transported through the environment via runoff, leaching, and land application of manure; however, airborne transport from feed yards has not been characterized. The goal of this study was to determine the extent to which antibiotics, antibiotic resistance genes (ARG), and ruminant-associated microbes are aerially dispersed via particulate matter (PM) derived from large-scale beef cattle feed yards. PM was collected downwind and upwind of 10 beef cattle feed yards. After extraction from PM, five veterinary antibiotics were quantified via high-performance liquid chromatography with tandem mass spectrometry, ARG were quantified via targeted quantitative polymerase chain reaction, and microbial community diversity was analyzed via 16S rRNA amplification and sequencing. Airborne PM derived from feed yards facilitated dispersal of several veterinary antibiotics, as well as microbial communities containing ARG. Concentrations of several antibiotics in airborne PM immediately downwind of feed yards ranged from 0.5 to 4.6 μg/g of PM. Microbial communities of PM collected downwind of feed yards were enriched with ruminant-associated taxa and were distinct when compared to upwind PM assemblages. Furthermore, genes encoding resistance to tetracycline antibiotics were significantly more abundant in PM collected downwind of feed yards as compared to upwind. Wind-dispersed PM from feed yards harbors antibiotics, bacteria, and ARGs.

  14. Prediction of antibiotic resistance from antibiotic resistance genes detected in antibiotic-resistant commensal Escherichia coli using PCR or WGS.

    Science.gov (United States)

    Moran, Robert A; Anantham, Sashindran; Holt, Kathryn E; Hall, Ruth M

    2017-03-01

    To assess the effectiveness of bioinformatic detection of resistance genes in whole-genome sequences in correctly predicting resistance phenotypes. Genomes of a collection of well-characterized commensal Escherichia coli were sequenced using Illumina HiSeq technology and assembled with SPAdes. Antibiotic resistance genes identified by PCR, SRST2 analysis of reads and ResFinder analysis of SPAdes assemblies were compared with known resistance phenotypes. Generally, the antibiotic resistance genes detected using bioinformatic methods were concordant, but only ARG-ANNOT included sat2 . However, the presence or absence of genes was not always predictive of the phenotype. In one strain, trimethoprim resistance was due to a known mutation in the chromosomal folA gene. In cases where the copy number was low, the aadA5 gene downstream of dfrA17 did not confer streptomycin or spectinomycin resistance. Resistance genes were found in the genomes that were not detected previously by PCRs targeting a limited gene set and gene cassettes in class 1 or class 2 integrons. In one isolate, the aadA1 gene cassette in the estX - aadA1 cassettes pair was outside an integron context and was not expressed. The qnrS1 gene, conferring reduced susceptibility to fluoroquinolones, and the bla CMY-2 gene, encoding an ESBL, were each detected in a single isolate and mphA (macrolide resistance) was present in six isolates surrounded by IS 26 and IS 6100 . WGS analysis detected more genes than PCR. Some were not expressed, causing inconsistencies with the experimentally determined phenotype. An unpredicted chromosomal folA mutation causing trimethoprim resistance was found.

  15. Mobile antibiotic resistance – the spread of genes determining the resistance of bacteria through food products

    Directory of Open Access Journals (Sweden)

    Jolanta Godziszewska

    2016-07-01

    Full Text Available In recent years, more and more antibiotics have become ineffective in the treatment of bacterial nfections. The acquisition of antibiotic resistance by bacteria is associated with circulation of genes in the environment. Determinants of antibiotic resistance may be transferred to pathogenic bacteria. It has been shown that conjugation is one of the key mechanisms responsible for spread of antibiotic resistance genes, which is highly efficient and allows the barrier to restrictions and modifications to be avoided. Some conjugative modules enable the transfer of plasmids even between phylogenetically distant bacterial species. Many scientific reports indicate that food is one of the main reservoirs of these genes. Antibiotic resistance genes have been identified in meat products, milk, fruits and vegetables. The reason for such a wide spread of antibiotic resistance genes is the overuse of antibiotics by breeders of plants and animals, as well as by horizontal gene transfer. It was shown, that resistance determinants located on mobile genetic elements, which are isolated from food products, can easily be transferred to another niche. The antibiotic resistance genes have been in the environment for 30 000 years. Their removal from food products is not possible, but the risks associated with the emergence of multiresistant pathogenic strains are very large. The only option is to control the emergence, selection and spread of these genes. Therefore measures are sought to prevent horizontal transfer of genes. Promising concepts involve the combination of developmental biology, evolution and ecology in the fight against the spread of antibiotic resistance.

  16. Generation of novel resistance genes using mutation and targeted gene editing

    Science.gov (United States)

    Classical breeding for virus resistance is a lengthy process and is restricted by the availability of resistance genes. Precise genome editing is a "dream technology" to improve plants for virus resistance and these tools have opened new and very promising ways to generate virus resistant plants by ...

  17. Antibacterial resistance of Enterococcus spp. isolated from commercial poultry of the Russian Federation farms in 2013–2016, and identification of vancomycin resistance genes

    Directory of Open Access Journals (Sweden)

    E. A. Svetoch

    2017-01-01

    Full Text Available Rationale: Enterococci are the leading cause of a number of nosocomial and community-acquired human diseases. In the last decade, these pathogens are becoming resistant to antibacterials, including vancomycin. Multidrug-resistant enterococci have been also isolated from agricultural animals in many countries worldwide, which raises concern of scientists because of possible horizontal transfer of resistance genes. Aim: To assess antibacterial sensitivity of Enterococcus spp. isolates collected from the poultry in the Russian Federation from 2013 to 2016, and to identify vancomycin-resistance genes in their genomes. Materials and methods: Eightyseven enterococci isolates belonging to E.  faecalis (n=47, 54%, E.  faecium (n=25, 28.7% and other species (n=15, 17.2% were collected from clinical samples of 297 heads of poultry (liver, lungs, heart, spleen, contents of the nasal and sinus cavities from 17  poultry farms of the Northwest, Central, Volga, Ural and Southern Federal districts of the Russian Federation. Sensitivity of enterococci to antibacterials was determined by disk-diffusion and broth microdilution methods. Vancomycin resistance genes van was detected by polymerase chain reaction with specific primers. Results: Most enterococci isolates were resistant to erythromycin (74/87, 85.1%, gentamicin (70/87, 80.5%, ceftriaxone (61/87, 70.1%, ciprofloxacin (56/87, 64.4%, tetracycline (57/87, 65.5%, and rifampicin (48/87, 55.2%, fewer ones to trimethoprim (38/87, 43.7%, ampicillin (28/87, 32.2%, linezolid (15/87, 17.2% and chloramphenicol (5/87, 5.7%. The vanC type genes (vanC1 and vanC2/3 were identified in 10  isolates. Vancomycin minimal inhibitory concentrations for these isolates were 2 to 8  mg/L. E. faecium with vanC1 gene was isolated from poultry probably for the first time ever. Conclusion: Commercial poultry in the Russian poultry farms is an important reservoir and source of antibiotic-resistant enterococci populations

  18. Characterization of Integrons and Resistance Genes in Salmonella Isolates from Farm Animals in Shandong Province, China

    Directory of Open Access Journals (Sweden)

    Xiaonan Zhao

    2017-07-01

    Full Text Available A total of 154 non-duplicate Salmonella isolates were recovered from 1,105 rectal swabs collected from three large-scale chicken farms (78/325, 24.0%, three large-scale duck farms (56/600, 9.3% and three large-scale pig farms (20/180, 11.1% between April and July 2016. Seven serotypes were identified among the 154 isolates, with the most common serotype in chickens and ducks being Salmonella enteritidis and in pigs Salmonella typhimurium. Antimicrobial susceptibility testing revealed that high antimicrobial resistance rates were observed for tetracycline (72.0% and ampicillin (69.4% in all sources. Class 1 integrons were detected in 16.9% (26/154 of these isolates and contained gene cassettes aadA2, aadA1, drfA1-aadA1, drfA12-aadA2, and drfA17-aadA5. Three β-lactamase genes were detected among the 154 isolates, and most of the isolates carried blaTEM−1(55/154, followed by blaPSE−1(14/154 and blaCTX−M−55 (11/154. Three plasmid-mediated quinolone resistance genes were detected among the 154 isolates, and most of the isolates carried qnrA (113/154, followed by qnrB (99/154 and qnrS (10/154. Fifty-four isolates carried floR among the 154 isolates. Multilocus sequence typing (MLST analysis showed that nine sequence types (STs were identified; ST11 was the most frequent genotype in chickens and ducks, and ST19 was identified in pigs. Our findings indicated that Salmonella was widespread, and the overuse of antibiotics in animals should be reduced considerably in developing countries.

  19. The Number of Genes Controlling Resistance in Beans to Common ...

    African Journals Online (AJOL)

    At V3, two to many genes were found to control resistance with segregation ratios that were significantly (P≤0.05) different from that of three gene pairs. In some crosses transgressive segregation was observed. By application of appropriate variances to the equation provided by Stanisfield's formula, the number of genes in ...

  20. Isolation of candidate disease resistance genes from enrichment ...

    African Journals Online (AJOL)

    Full sequencing of a clone revealed a gene similar to a putative brassinosteroid LRR receptor kinase in japonica rice; the protein structure analysis suggested that it may be a disease resistance gene or functionally involved in a signal transduction pathway. These results indicate these clones may include new R genes and ...

  1. Identification of Tet45, a tetracycline efflux pump, from a poultry-litter-exposed soil isolate and persistence of tet(45) in the soil.

    Science.gov (United States)

    You, Yaqi; Hilpert, Markus; Ward, Mandy J

    2013-09-01

    To characterize a tetracycline resistance (Tc(R)) determinant, closely related to the TetL efflux pump, in a Bhargavaea cecembensis strain previously isolated from a poultry-litter-impacted soil. Genomic DNA of B. cecembensis DMV42A was shotgun cloned and expressed in Escherichia coli. Antimicrobial susceptibility testing and a [(3)H]tetracycline uptake assay were used to confirm the function of the target gene. Transferability of the gene was examined using filter matings and confirmed by PCR and sequencing. Real-time quantitative PCR was performed on soil metagenomic DNA to evaluate the prevalence of the gene in the soil from which B. cecembensis DMV42A was isolated and in more pristine local soils. The Tc(R) determinant from B. cecembensis DMV42A, designated Tet45, was identified as a tetracycline efflux pump sharing 78% amino acid identity with certain TetL proteins. In B. cecembensis DMV42A, tet(45) was adjacent to truncated and non-functional arsenic resistance genes with high sequence similarities to genes from staphylococcal plasmids. After filter matings, the tet(45) gene could be found in E. coli transconjugants, although the transfer mechanism was unknown. Tet45 homologues are also present in the genomes of several Bacillus cereus strains and a Bacillus thuringiensis strain. tet(45) was detected in the poultry-litter-impacted soil, and persisted at a similar level 2 years after removal of the chicken waste, although it was not detected in several more pristine soils. Tet45 is a tetracycline efflux pump closely related to TetL. Horizontal gene transfer may have contributed to the dissemination and persistence of tet(45) in a poultry-litter-impacted soil.

  2. Aerobic composting reduces antibiotic resistance genes in cattle manure and the resistome dissemination in agricultural soils.

    Science.gov (United States)

    Gou, Min; Hu, Hang-Wei; Zhang, Yu-Jing; Wang, Jun-Tao; Hayden, Helen; Tang, Yue-Qin; He, Ji-Zheng

    2018-01-15

    Composting has been suggested as a potential strategy to eliminate antibiotic residues and pathogens in livestock manure before its application as an organic fertilizer in agro-ecosystems. However, the impacts of composting on antibiotic resistance genes (ARGs) in livestock manure and their temporal succession following the application of compost to land are not well understood. We examined how aerobic composting affected the resistome profiles of cattle manure, and by constructing laboratory microcosms we compared the effects of manure and compost application to agricultural soils on the temporal succession of a wide spectrum of ARGs. The high-throughput quantitative PCR array detected a total of 144 ARGs across all the soil, manure and compost samples, with Macrolide-Lincosamide-Streptogramin B, aminoglycoside, multidrug, tetracycline, and β-lactam resistance as the most dominant types. Composting significantly reduced the diversity and relative abundance of ARGs and mobile genetic elements (MGEs) in the cattle manure. In the 120-day microcosm incubation, the diversity and abundance of ARGs in manure-treated soils were significantly higher than those in compost-treated soils at the beginning of the experiment. The level of antibiotic resistance rapidly declined over time in all manure- and compost-treated soils, coupled with similar temporal patterns of manure- and compost-derived bacterial communities as revealed by SourceTracker analysis. The network analysis revealed more intensive interactions/associations among ARGs and MGEs in manure-treated soils than in compost-treated soils, suggesting that mobility potential of ARGs was lower in soils amended with compost. Our results provide evidence that aerobic composting of cattle manure may be an effective approach to mitigate the risk of antibiotic resistance propagation associated with land application of organic wastes. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Antimicrobial resistance of Escherichia coli isolates from broiler chickens and humans

    Directory of Open Access Journals (Sweden)

    Brown Paul D

    2006-02-01

    Full Text Available Abstract Background Antimicrobial usage is considered the most important factor promoting the emergence, selection and dissemination of antimicrobial-resistant microorganisms in both veterinary and human medicine. The aim of this study was to investigate the prevalence and genetic basis of tetracycline resistance in faecal Escherichia coli isolates from healthy broiler chickens and compare these data with isolates obtained from hospitalized patients in Jamaica. Results Eighty-two E. coli strains isolated from faecal samples of broiler chickens and urine and wound specimens of hospitalized patients were analyzed by agar disc diffusion to determine their susceptibility patterns to 11 antimicrobial agents. Tetracycline resistance determinants were investigated by plasmid profiling, transformations, and amplification of plasmid-borne resistance genes. Tetracycline resistance occurred at a frequency of 82.4% in avian isolates compared to 43.8% in human isolates. In addition, among avian isolates there was a trend towards higher resistance frequencies to kanamycin and nalidixic acid (p E. coli. Tetracycline resistance was mediated by efflux genes tetB and/or tetD. Conclusion The present study highlights the prevalence of multiple drug resistant E. coli among healthy broiler chickens in Jamaica, possibly associated with expression of tetracycline resistance. While there did not appear to be a common source for multiple drug resistance in the strains from avian or human origin, the genes encoding resistance are similar. These results suggest that genes are disseminated in the environment and warrant further investigation of the possibility for avian sources acting as reservoirs for tetracycline resistance.

  4. Comparative analysis of soybean genotype resistance to Heterodera glycines and Meloidogyne species via resistance gene analogs.

    Science.gov (United States)

    Vieira, P M H; Arêdes, F A S; Ferreira, A; Ferreira, M F S

    2016-09-02

    Nematodes are important pests of soybean throughout the world and cause high yield losses. As a control strategy, the identification of resistance genes is an important aim of breeding studies. Plants possess resistance genes (R), which are responsible for the recognition of pathogens and activation of the defense system. R genes and resistance gene analogs (RGAs) possess conserved domains, from which nucleotide-binding site is the most common. Using degenerate primers originating from these domains, it is possible to identify and isolate sequences of R and RGA genes. In this study, soybean genotypes resistant to the nematodes Heterodera glycines, Meloidogyne incognita, M. javanica, and M. enterolobii were compared by the use of RGAs and simple sequence repeat (SSR) markers. Forty-six soybean genotypes were studied, including plant introductions (PIs), commercial crops, and source of resistance genotypes. Thirteen combinations of RGA primers and different SSRs linked to QTLs were used to confirm resistance to soybean cyst nematodes (SCN). Fragments associated with resistance to the studied nematodes were amplified in the source of resistance and PI genotypes. RGA markers were efficient at distinguishing groups of genotypes that were resistant and susceptible to Meloidogyne spp and SCN. Combinations of specific primers were identified through their ability to amplify nucleotide sequences from possible resistance candidate genes. SSR markers contributed to the analysis of SCN race specificity, showing that the QTLs identified by these markers are distinct from those identified by RGA markers.

  5. Expression changes of antioxidant, apoptotic, anti-apoptotic genes and miR-15b-34a-21-98 in over tissue by using erythromycin, quinacrine and tetracycline in non-surgical sterilization.

    Science.gov (United States)

    Kara, Murat; Yumrutas, Onder; Atilgan, Remzi; Baspinar, Melike; Sapmaz, Ekrem; Kuloglu, Tuncay

    2014-12-01

    In the present study, effects on expression of antioxidant, apoptotic and anti-apoptotic genes (GSR, GRX3, SOD1, RAI-NOS, HSP7, BAX, Bcl-2, CASP3 and MDH1) of substances being used in non-surgical sterilization such as quinacrine, erythromycin and tetracycline were evaluated in over tissue. Moreover, expression of some specific mi-RNA (miR-15b, miR-21, miR34a and miR-98) that playing a role in apoptosis was determined in same tissue. Prospective comparative experimental study. Genetics and Histology laboratory. Total number of 28 Wistar albino 12-14 week old female rats with regular cycles and 200-220 grams in weight. Total RNA was isolated from tissues by using a RNA isolation kit. Gene expression levels were evaluated by Real-Time PCR method. Tubal passage and fibrosis induction in tissues was observed in the histochemical analysis. In the statistical analysis of data Kruskal-Wallis variance analysis and Mann-Whitney U test were used and p sterilization effect poorly the expression of anti-oxidant, apoptotic and anti-apoptotic genes, but the expression of miR-34 playing the role in apoptosis increased after treatment of these substances.

  6. Generation of novel resistance genes using mutation and targeted gene editing.

    Science.gov (United States)

    Gal-On, Amit; Fuchs, Marc; Gray, Stewart

    2017-10-01

    Classical breeding for virus resistance is a lengthy process and is restricted by the availability of resistance genes. Precise genome editing is a 'dream technology' to improve plants for virus resistance and these tools have opened new and very promising ways to generate virus resistant plants by disrupting host susceptibility genes, or by increasing the expression of viral resistance genes. However, precise targets must be identified and their roles understood to minimize potential negative effects on the plant. Nonetheless, the opportunities for genome editing are expanding, as are the technologies to generate effective and broad-spectrum resistance against plant viruses. Here we provide insights into recent progress related to gene targets and gene editing technologies. Published by Elsevier B.V.

  7. Prevalence and proliferation of antibiotic resistance genes in two municipal wastewater treatment plants.

    Science.gov (United States)

    Mao, Daqing; Yu, Shuai; Rysz, Michal; Luo, Yi; Yang, Fengxia; Li, Fengxiang; Hou, Jie; Mu, Quanhua; Alvarez, P J J

    2015-11-15

    The propagation of antibiotic resistance genes (ARGs) is an emerging health concern worldwide. Thus, it is important to understand and mitigate their occurrence in different systems. In this study, 30 ARGs that confer resistance to tetracyclines, sulfonamides, quinolones or macrolides were detected in two activated sludge wastewater treatment plants (WWTPs) in northern China. Bacteria harboring ARGs persisted through all treatment units, and survived disinfection by chlorination in greater percentages than total Bacteria (assessed by 16S rRNA genes). Although the absolute abundances of ARGs were reduced from the raw influent to the effluent by 89.0%-99.8%, considerable ARG levels [(1.0 ± 0.2) × 10(3) to (9.5 ± 1.8) × 10(5) copies/mL)] were found in WWTP effluent samples. ARGs were concentrated in the waste sludge (through settling of bacteria and sludge dewatering) at (1.5 ± 2.3) × 10(9) to (2.2 ± 2.8) × 10(11) copies/g dry weight. Twelve ARGs (tetA, tetB, tetE, tetG, tetH, tetS, tetT, tetX, sul1, sul2, qnrB, ermC) were discharged through the dewatered sludge and plant effluent at higher rates than influent values, indicating overall proliferation of resistant bacteria. Significant antibiotic concentrations (2%-50% of raw influent concentrations) remained throughout all treatment units. This apparently contributed selective pressure for ARG replication since the relative abundance of resistant bacteria (assessed by ARG/16S rRNA gene ratios) was significantly correlated to the corresponding effluent antibiotic concentrations. Similarly, the concentrations of various heavy metals (which induce a similar bacterial resistance mechanism as antibiotics - efflux pumps) were also correlated to the enrichment of some ARGs. Thus, curtailing the release of antibiotics and heavy metals to sewage systems (or enhancing their removal in pre-treatment units) may alleviate their selective pressure and mitigate ARG proliferation in WWTPs. Copyright © 2015 Elsevier Ltd. All

  8. A soybean cyst nematode resistance gene points to a new mechanism of plant resistance to pathogens.

    Science.gov (United States)

    Liu, Shiming; Kandoth, Pramod K; Warren, Samantha D; Yeckel, Greg; Heinz, Robert; Alden, John; Yang, Chunling; Jamai, Aziz; El-Mellouki, Tarik; Juvale, Parijat S; Hill, John; Baum, Thomas J; Cianzio, Silvia; Whitham, Steven A; Korkin, Dmitry; Mitchum, Melissa G; Meksem, Khalid

    2012-12-13

    Soybean (Glycine max (L.) Merr.) is an important crop that provides a sustainable source of protein and oil worldwide. Soybean cyst nematode (Heterodera glycines Ichinohe) is a microscopic roundworm that feeds on the roots of soybean and is a major constraint to soybean production. This nematode causes more than US$1 billion in yield losses annually in the United States alone, making it the most economically important pathogen on soybean. Although planting of resistant cultivars forms the core management strategy for this pathogen, nothing is known about the nature of resistance. Moreover, the increase in virulent populations of this parasite on most known resistance sources necessitates the development of novel approaches for control. Here we report the map-based cloning of a gene at the Rhg4 (for resistance to Heterodera glycines 4) locus, a major quantitative trait locus contributing to resistance to this pathogen. Mutation analysis, gene silencing and transgenic complementation confirm that the gene confers resistance. The gene encodes a serine hydroxymethyltransferase, an enzyme that is ubiquitous in nature and structurally conserved across kingdoms. The enzyme is responsible for interconversion of serine and glycine and is essential for cellular one-carbon metabolism. Alleles of Rhg4 conferring resistance or susceptibility differ by two genetic polymorphisms that alter a key regulatory property of the enzyme. Our discovery reveals an unprecedented plant resistance mechanism against a pathogen. The mechanistic knowledge of the resistance gene can be readily exploited to improve nematode resistance of soybean, an increasingly important global crop.

  9. Tetracyclines Disturb Mitochondrial Function across Eukaryotic Models: A Call for Caution in Biomedical Research

    Directory of Open Access Journals (Sweden)

    Norman Moullan

    2015-03-01

    Full Text Available In recent years, tetracyclines, such as doxycycline, have become broadly used to control gene expression by virtue of the Tet-on/Tet-off systems. However, the wide range of direct effects of tetracycline use has not been fully appreciated. We show here that these antibiotics induce a mitonuclear protein imbalance through their effects on mitochondrial translation, an effect that likely reflects the evolutionary relationship between mitochondria and proteobacteria. Even at low concentrations, tetracyclines induce mitochondrial proteotoxic stress, leading to changes in nuclear gene expression and altered mitochondrial dynamics and function in commonly used cell types, as well as worms, flies, mice, and plants. Given that tetracyclines are so widely applied in research, scientists should be aware of their potentially confounding effects on experimental results. Furthermore, these results caution against extensive use of tetracyclines in livestock due to potential downstream impacts on the environment and human health.

  10. Prevalence of virulence and antimicrobial resistance genes in Salmonella spp. isolated from commercial chickens and human clinical isolates from South Africa and Brazil

    Directory of Open Access Journals (Sweden)

    Oliver T. Zishiri

    2016-03-01

    Full Text Available Salmonellosis is a significant public health concern around the world. The injudicious use of antimicrobial agents in poultry production for treatment, growth promotion and prophylaxis has resulted in the emergence of drug resistant strains of Salmonella. The current study was conducted to investigate the prevalence of virulence and antimicrobial resistance genes from Salmonella isolated from South African and Brazilian broiler chickens as well as human clinical isolates. Out of a total of 200 chicken samples that were collected from South Africa 102 (51% tested positive for Salmonella using the InvA gene. Of the overall 146 Salmonella positive samples that were screened for the iroB gene most of them were confirmed to be Salmonella enterica with the following prevalence rates: 85% of human clinical samples, 68.6% of South African chicken isolates and 70.8% of Brazilian chicken samples. All Salmonella isolates obtained were subjected to antimicrobial susceptibility testing with 10 antibiotics. Salmonella isolates from South African chickens exhibited resistance to almost all antimicrobial agents used, such as tetracycline (93%, trimethoprim-sulfamthoxazole (84%, trimethoprim (78.4%, kanamycin (74%, gentamicin (48%, ampicillin (47%, amoxicillin (31%, chloramphenicol (31%, erythromycin (18% and streptomycin (12%. All samples were further subjected to PCR in order to screen some common antimicrobial and virulence genes of interest namely spiC, pipD, misL, orfL, pse-1, tet A, tet B, ant (3"-la, sul 1 and sul. All Salmonella positive isolates exhibited resistance to at least one antimicrobial agent; however, antimicrobial resistance patterns demonstrated that multiple drug resistance was prevalent. The findings provide evidence that broiler chickens are colonised by pathogenic Salmonella harbouring antimicrobial resistance genes. Therefore, it is evident that there is a need for prudent use of antimicrobial agents in poultry production systems in

  11. Potential Candidate Genes for Improving Rice Disease Resistance

    National Research Council Canada - National Science Library

    Delteil, Amandine; Zhang, Jie; Lessard, Philippe; Morel, Jean-Benoit

    2010-01-01

    .... oryzae are responsible for considerable yield loss. Up to now, in rice, the modification of the expression of more than 60 genes from diverse origins has shown beneficial effects with respect to disease resistance...

  12. Resistance gene management: concepts and practice

    Science.gov (United States)

    Christopher C. Mundt

    2012-01-01

    There is now a very long history of genetics/breeding for disease resistance in annual crops. These efforts have resulted in conceptual advances and frustrations, as well as practical successes and failures. This talk will review this history and its relevance to the genetics of resistance in forest species. All plant breeders and pathologists are familiar with boom-...

  13. Relation between genetic markers of drug resistance and susceptibility profile of clinical Neisseria gonorrhoeae strains.

    Science.gov (United States)

    Ilina, Elena N; Vereshchagin, Vladimir A; Borovskaya, Alexandra D; Malakhova, Maja V; Sidorenko, Sergei V; Al-Khafaji, Nazar C; Kubanova, Anna A; Govorun, Vadim M

    2008-06-01

    The main goal of this work is to clarify the predictive value of known genetic markers of Neisseria gonorrhoeae resistance to penicillin, tetracycline, and fluoroquinolones. The correlation between the presence of certain genetic markers and susceptibility of N. gonorrhoeae isolates to penicillin, tetracycline, and fluoroquinolones has been analyzed by means of statistical methods. Susceptibility testing with penicillin, tetracycline, and fluoroquinolones was performed by the agar dilution method. N. gonorrhoeae genomic DNA was isolated. The presence of bla(TEM-1) and tet(M) genes was analyzed by PCR. A novel method of polymorphism discovery based on a minisequencing reaction followed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry was applied for the analysis of chromosomal N. gonorrhoeae genes involved in antimicrobial resistance development. Clinical N. gonorrhoeae isolates (n = 464) were collected. Susceptibility levels to penicillin, tetracycline, and fluoroquinolones were found to be 25.9%, 35.9%, and 54.1%, respectively. Among the 19 N. gonorrhoeae isolates with penicillin MICs of > or =4 microg/ml, the bla(TEM-1) gene was detected in 12. The Tet(M) determinant was found in 4 of 12 N. gonorrhoeae isolates with tetracycline MICs of > or =16 microg/ml. The chromosomal genetic markers of penicillin and tetracycline resistance were detected especially in isolates with penicillin MICs of 0.25 to 2.0 microg/ml and tetracycline MICs of 0.5 to 4 microg/ml. Mutations in GyrA and ParC were found in 208 of 211 quinolone-resistant N. gonorrhoeae isolates. This work is the first representative molecular research of the N. gonorrhoeae population in Russia. Information about the prevalence of antibiotic resistance mechanisms and the positive predictive value of certain genetic determinants is given. The positive predictive values of the analyzed genetic markers were found to be different for fluoroquinolones (90.3%), penicillin (91.1%), and

  14. Prevalence of the Antibiotic Resistance Genes in Coagulase-Positive-and Negative-Staphylococcus in Chicken Meat Retailed to Consumers

    Science.gov (United States)

    Osman, Kamelia; Badr, Jihan; Al-Maary, Khalid S.; Moussa, Ihab M. I.; Hessain, Ashgan M.; Girah, Zeinab M. S. Amin; Abo-shama, Usama H.; Orabi, Ahmed; Saad, Aalaa

    2016-01-01

    The use of antibiotics in farm management (growing crops and raising animals) has become a major area of concern. Its implications is the consequent emergence of antibiotic resistant bacteria (ARB) and accordingly their access into the human food chain with passage of antibiotic resistance genes (ARG) to the normal human intestinal microbiota and hence to other pathogenic bacteria causative human disease. Therefore, we pursued in this study to unravel the frequency and the quinolone resistance determining region, mecA and cfr genes of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), methicillin-resistant coagulase-negative staphylococci (MRCNS) and methicillin-susceptible coagulase-negative staphylococci (MSCNS) isolated from the retail trade of ready-to-eat raw chicken meat samples collected during 1 year and sold across the Great Cairo area. The 50 Staphylococcus isolated from retail raw chicken meat were analyzed for their antibiotic resistance phenotypic profile on 12 antibiotics (penicillin, oxacillin, methicillin, ampicillin-sulbactam, erythromycin, tetracycline, clindamycin, gentamicin, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim, and vancomycin) and their endorsement of the quinolone resistance determining region, mecA and cfr genes. The isolation results revealed 50 isolates, CPS (14) and CNS (36), representing ten species (S. aureus, S. hyicus, S. epidermedius, S. lugdunensis, S. haemolyticus, S. hominus, S. schleiferi, S. cohnii, S. intermedius, and S. lentus). Twenty seven isolates were methicillin-resistant. Out of the characterized 50 staphylococcal isolates, three were MRSA but only 2/3 carried the mecA gene. The ARG that bestows resistance to quinolones, β-lactams, macrolides, lincosamides, and streptogramin B [MLS(B)] in MRSA and MR-CNS were perceived. According to the available literature, the present investigation was a unique endeavor into the identification of the quinolone-resistance

  15. Prevalence of the antibiotic resistance genes in coagulase-positive- and negative-Staphylococcus in chicken meat retailed to consumers

    Directory of Open Access Journals (Sweden)

    Kamelia Mahmoud Osman

    2016-11-01

    Full Text Available The use of antibiotics in farm management (growing crops and raising animals has become a major area of concern. Its implications is the consequent emergence of antibiotic resistant bacteria (ARB and accordingly their access into the human food chain with passage of antibiotic resistance genes (ARG to the normal human intestinal microbiota and hence to other pathogenic bacteria causative human disease. Therefore, we pursued in this study to unravel the frequency and the quinolone resistance determining region, mecA and cfr genes of methicillin-susceptible Staphylococcus aureus (MSSA, methicillin-resistant S. aureus (MRSA, methicillin-resistant coagulase-negative staphylococci (MRCNS and methicillin-susceptible coagulase-negative staphylococci (MSCNS isolated from the retail trade of ready-to-eat raw chicken meat samples collected during one year and sold across the Great Cairo area. The 50 Staphylococcus isolated from retail raw chicken meat were analyzed for their antibiotic resistance phenotypic profile on 12 antibiotics (penicillin, oxacillin, methicillin, ampicillin-sulbactam, erythromycin, tetracycline, clindamycin, gentamicin, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim and vancomycin and their endorsement of the quinolone resistance determining region, mecA and cfr genes. The isolation results revealed 50 isolates, CPS (14 and CNS (36, representing ten species (S. aureus, S. hyicus, S. epidermedius, S. lugdunensis, S. haemolyticus, S. hominus, S. schleiferi, S. cohnii, S. intermedius and S. lentus. Twenty seven isolates were methicillin-resistant. Out of the characterized 50 staphylococcal isolates, three were MRSA but only 2/3 carried the mecA gene. The ARG that bestows resistance to quinolones, β-lactams, macrolides, lincosamides and streptogramin B (MLS(B in MRSA and MR-CNS were perceived. According to the available literature, the present investigation was a unique endeavor into the identification of the quinolone-resistance

  16. Prevalence of the Antibiotic Resistance Genes in Coagulase-Positive-and Negative-Staphylococcus in Chicken Meat Retailed to Consumers.

    Science.gov (United States)

    Osman, Kamelia; Badr, Jihan; Al-Maary, Khalid S; Moussa, Ihab M I; Hessain, Ashgan M; Girah, Zeinab M S Amin; Abo-Shama, Usama H; Orabi, Ahmed; Saad, Aalaa

    2016-01-01

    The use of antibiotics in farm management (growing crops and raising animals) has become a major area of concern. Its implications is the consequent emergence of antibiotic resistant bacteria (ARB) and accordingly their access into the human food chain with passage of antibiotic resistance genes (ARG) to the normal human intestinal microbiota and hence to other pathogenic bacteria causative human disease. Therefore, we pursued in this study to unravel the frequency and the quinolone resistance determining region, mecA and cfr genes of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), methicillin-resistant coagulase-negative staphylococci (MRCNS) and methicillin-susceptible coagulase-negative staphylococci (MSCNS) isolated from the retail trade of ready-to-eat raw chicken meat samples collected during 1 year and sold across the Great Cairo area. The 50 Staphylococcus isolated from retail raw chicken meat were analyzed for their antibiotic resistance phenotypic profile on 12 antibiotics (penicillin, oxacillin, methicillin, ampicillin-sulbactam, erythromycin, tetracycline, clindamycin, gentamicin, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim, and vancomycin) and their endorsement of the quinolone resistance determining region, mecA and cfr genes. The isolation results revealed 50 isolates, CPS (14) and CNS (36), representing ten species (S. aureus, S. hyicus, S. epidermedius, S. lugdunensis, S. haemolyticus, S. hominus, S. schleiferi, S. cohnii, S. intermedius, and S. lentus). Twenty seven isolates were methicillin-resistant. Out of the characterized 50 staphylococcal isolates, three were MRSA but only 2/3 carried the mecA gene. The ARG that bestows resistance to quinolones, β-lactams, macrolides, lincosamides, and streptogramin B [MLS(B)] in MRSA and MR-CNS were perceived. According to the available literature, the present investigation was a unique endeavor into the identification of the quinolone-resistance

  17. The antimicrobial resistance crisis: management through gene monitoring

    Science.gov (United States)

    2016-01-01

    Antimicrobial resistance (AMR) is an acknowledged crisis for humanity. Its genetic origins and dire potential outcomes are increasingly well understood. However, diagnostic techniques for monitoring the crisis are currently largely limited to enumerating the increasing incidence of resistant pathogens. Being the end-stage of the evolutionary process that produces antimicrobial resistant pathogens, these measurements, while diagnostic, are not prognostic, and so are not optimal in managing this crisis. A better test is required. Here, using insights from an understanding of evolutionary processes ruling the changing abundance of genes under selective pressure, we suggest a predictive framework for the AMR crisis. We then discuss the likely progression of resistance for both existing and prospective antimicrobial therapies. Finally, we suggest that by the environmental monitoring of resistance gene frequency, resistance may be detected and tracked presumptively, and how this tool may be used to guide decision-making in the local and global use of antimicrobials. PMID:27831476

  18. Occurrence of intracellular and extracellular antibiotic resistance genes in coastal areas of Bohai Bay (China) and the factors affecting them.

    Science.gov (United States)

    Zhang, Yongpeng; Niu, Zhiguang; Zhang, Ying; Zhang, Kai

    2018-01-29

    Coastal areas are the transition zones between ocean and land where intracellular antibiotic resistance genes (iARGs) and extracellular antibiotic resistance genes (eARGs) could spread among marine organisms, and between humans and marine organisms. However, little attention has been paid to the combined research on iARGs and eARGs in marine environment. In this context, we collected water and sediment samples from the coastal areas of the Bohai Bay in China and performed molecular and chemical analyses. The results of quantitative real-time PCR (qPCR) showed that the relative abundance of eARGs was up to 4.3 ± 1.3 × 10 -1 gene copies/16S rRNA copies in the water samples and 2.6 ± 0.3 × 10 -3 gene copies/16S rRNA copies in the sediment samples. Also, the abundance of eARGs was significantly higher than that of iARGs. Furthermore, the average abundances of antibiotic resistance genes (ARGs, include iARGs and eARGs) were the highest in both the water and sediment samples from the estuaries. The results of liquid chromatography-mass spectrometry showed that the concentrations of antibiotics in estuaries and areas near the mariculture site were higher than that in the other sites. The class 1 integron gene (int1) and sul1 in the intracellular DNA were significantly correlated in the water samples. Moreover, significant correlation between int1 and sul2 in the extracellular DNA was also found in the sediment samples. The combination of sulfamerazine and tetracycline as well as the combination of sulfamethazine and dissolved oxygen can both explain the abundance of ARGs, implying the combined effects of multiple stresses on ARGs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Characterization of Antibiotics and Antibiotic Resistance Genes on an Ecological Farm System

    Directory of Open Access Journals (Sweden)

    Songhe Zhang

    2015-01-01

    Full Text Available There is a growing concern worldwide about the prevalence of antibiotics and antibiotic resistance genes (ARGs on the farm. In this study, we investigated the distribution of seven antibiotics and ten ARGs in fresh and dried pig feces, in biogas slurry, and in grape-planting soil from an ecological farm. Antibiotics including sulfamethazine, norfloxacin, ofloxacin, tetracycline, oxytetracycline, and chlortetracycline were detected in these samples (except for sulfamethoxazole in dried feces. In general, antibiotics levels in samples were in the sequence: biogas slurry > fresh feces > soil or dried feces. Results of ecological risk assessments revealed that among the seven antibiotics chlortetracycline showed the highest ecological risk. Among the ten ARGs, sulI and tetO were the most prevalent on this ecological farm. There were positive correlations between certain ARGs and the corresponding antibiotics on this ecological farm. Therefore, continuous monitoring of antibiotics and their corresponding ARGs should be conducted in the agroecosystem near the concentrated animal farming operation systems.

  20. The Number of Genes Controlling Resistance in Beans to Common ...

    African Journals Online (AJOL)

    Ten crosses were made between resistant (R), susceptible (S), RxS susceptible and Intermediate (I), SxI and RxR bean lines to common bacterial blight. The F1 were advanced to F2 and in each cross over 250 F2 plants were used to evaluate for the number of genes controlling resistance using Mendelian genetics and ...

  1. Exploiting natural variation to identify insect-resistance genes

    NARCIS (Netherlands)

    Broekgaarden, C.; Snoeren, T.A.L.; Dicke, M.; Vosman, B.

    2011-01-01

    Herbivorous insects are widespread and often serious constraints to crop production. The use of insect-resistant crops is a very effective way to control insect pests in agriculture, and the development of such crops can be greatly enhanced by knowledge on plant resistance mechanisms and the genes

  2. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    Inheritance and genetic mapping of stripe rust resistance gene in backcrossrecombinant inbred line (BC-RIL) population derived from the cross of a wheat–Ae. caudata introgression line (IL) T291-2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major ...

  3. Progress on introduction of rust resistance genes into confection sunflower

    Science.gov (United States)

    Sunflower rust (Puccinia helianthi) emerged as a serious disease in the last few years. Confection sunflower is particularly vulnerable to the disease due to the lack of resistance sources. The objectives of this project are to transfer rust resistance genes from oil sunflower to confectionery sunfl...

  4. Occurrence and reservoirs of antibiotic resistance genes in the environment

    NARCIS (Netherlands)

    Seveno, N.; Kallifidas, D.; Smalla, K.; Elsas, van J.D.; Collard, J.M.; Karagouni, A.; Wellington, E.M.H.

    2002-01-01

    Antibiotic resistance genes have become highly mobile since the development of antibiotic chemotherapy. A considerable body of evidence exists proving the link between antibiotic use and the significant increase in drug-resistant human bacterial pathogens. The application of molecular detection and

  5. improvement of resistance to fusarium root rot through gene

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    population. Annual Report of the Bean. Improvement Cooperative 47:83–84. Park, S.J. and Tu, J.C. 1994. Genetic segregation of root rot resistance in dry bean. Annual. Report of the Bean Improvement Cooperative. 37:403-408. Pedersen, L.W. and Leath, S. 1988. Pyramiding major genes for resistance to maintain residual.

  6. First study on characterization of virulence and antibiotic resistance genes in verotoxigenic and enterotoxigenic E. coli isolated from raw milk and unpasteurized traditional cheeses in Romania.

    Science.gov (United States)

    Tabaran, Alexandra; Mihaiu, Marian; Tăbăran, Flaviu; Colobatiu, Liora; Reget, Oana; Borzan, Mihai Marian; Dan, Sorin Daniel

    2017-03-01

    The study focused on the incidence of enterotoxigenic Escherichia coli (ETEC) and verotoxigenic E. coli (VTEC) in raw milk and traditional dairy cheeses marketed in Romania, characterizing the virulence and antibiotic resistance genes of these isolates. One hundred and twenty samples of raw milk and 80 samples of unpasteurized telemy cheese were collected and cultured according to the international standard protocol. All the characteristic E. coli cultures were analyzed for the presence of STa, STb, LT, stx1, and stx2 toxicity genes. The ETEC/VTEC strains were tested for the presence of antibiotic resistance genes, such as aadA1, tetA, tetB, tetC, tetG, dfrA1, qnrA, aaC, sul1, bla SHV , bla CMY , bla TEM , and ere(A), using PCR. The results showed that 27 samples (18.62%) were positive for one of the virulence genes investigated. 48.1% (n = 13) tested positive at the genes encoding for tetracycline resistance, tetA being the most prevalent one (61.5%; n = 8). A high percent (33.3%; n = 9) revealed the beta-lactamase (bla TEM ) resistance gene, and none of the samples tested positive for bla CMY and bla SHV genes. The genes responsible for resistance to sulfonamides (sul1) and trimethoprim (dfrA1) were detected in rates of 14.8% (n = 4) and 7.4% (n = 2), respectively. E. coli is highly prevalent in raw milk and unpasteurized cheeses marketed in Romania. These strains might represent an important reservoir of resistance genes which can easily spread into other European countries, given the unique market.

  7. Gene pyramiding enhances durable blast disease resistance in rice

    OpenAIRE

    Fukuoka, Shuichi; Saka, Norikuni; Mizukami, Yuko; Koga, Hironori; Yamanouchi, Utako; Yoshioka, Yosuke; Hayashi, Nagao; Ebana, Kaworu; Mizobuchi, Ritsuko; Yano, Masahiro

    2015-01-01

    Effective control of blast, a devastating fungal disease of rice, would increase and stabilize worldwide food production. Resistance mediated by quantitative trait loci (QTLs), which usually have smaller individual effects than R-genes but confer broad-spectrum or non-race-specific resistance, is a promising alternative to less durable race-specific resistance for crop improvement, yet evidence that validates the impact of QTL combinations (pyramids) on the durability of plant disease resista...

  8. Genome-Wide Architecture of Disease Resistance Genes in Lettuce.

    Science.gov (United States)

    Christopoulou, Marilena; Wo, Sebastian Reyes-Chin; Kozik, Alex; McHale, Leah K; Truco, Maria-Jose; Wroblewski, Tadeusz; Michelmore, Richard W

    2015-10-08

    Genome-wide motif searches identified 1134 genes in the lettuce reference genome of cv. Salinas that are potentially involved in pathogen recognition, of which 385 were predicted to encode nucleotide binding-leucine rich repeat receptor (NLR) proteins. Using a maximum-likelihood approach, we grouped the NLRs into 25 multigene families and 17 singletons. Forty-one percent of these NLR-encoding genes belong to three families, the largest being RGC16 with 62 genes in cv. Salinas. The majority of NLR-encoding genes are located in five major resistance clusters (MRCs) on chromosomes 1, 2, 3, 4, and 8 and cosegregate with multiple disease resistance phenotypes. Most MRCs contain primarily members of a single NLR gene family but a few are more complex. MRC2 spans 73 Mb and contains 61 NLRs of six different gene families that cosegregate with nine disease resistance phenotypes. MRC3, which is 25 Mb, contains 22 RGC21 genes and colocates with Dm13. A library of 33 transgenic RNA interference tester stocks was generated for functional analysis of NLR-encoding genes that cosegregated with disease resistance phenotypes in each of the MRCs. Members of four NLR-encoding families, RGC1, RGC2, RGC21, and RGC12 were shown to be required for 16 disease resistance phenotypes in lettuce. The general composition of MRCs is conserved across different genotypes; however, the specific repertoire of NLR-encoding genes varied particularly of the rapidly evolving Type I genes. These tester stocks are valuable resources for future analyses of additional resistance phenotypes. Copyright © 2015 Christopoulou et al.

  9. Horizontal gene transfer in the human gastrointestinal tract: potential spread of antibiotic resistance genes.

    Science.gov (United States)

    Huddleston, Jennifer R

    2014-01-01

    Bacterial infections are becoming increasingly difficult to treat due to widespread antibiotic resistance among pathogens. This review aims to give an overview of the major horizontal transfer mechanisms and their evolution and then demonstrate the human lower gastrointestinal tract as an environment in which horizontal gene transfer of resistance determinants occurs. Finally, implications for antibiotic usage and the development of resistant infections and persistence of antibiotic resistance genes in populations as a result of horizontal gene transfer in the large intestine will be discussed.

  10. Horizontal gene transfer in the human gastrointestinal tract: potential spread of antibiotic resistance genes

    Directory of Open Access Journals (Sweden)

    Huddleston JR

    2014-06-01

    Full Text Available Jennifer R HuddlestonBiology Department, Abilene Christian University, Abilene, TX, USAAbstract: Bacterial infections are becoming increasingly difficult to treat due to widespread antibiotic resistance among pathogens. This review aims to give an overview of the major horizontal transfer mechanisms and their evolution and then demonstrate the human lower gastrointestinal tract as an environment in which horizontal gene transfer of resistance determinants occurs. Finally, implications for antibiotic usage and the development of resistant infections and persistence of antibiotic resistance genes in populations as a result of horizontal gene transfer in the large intestine will be discussed.Keywords: gut microbiome, conjugation, natural transformation, transduction

  11. Gentamicin resistance genes in environmental bacteria: prevalence and transfer

    NARCIS (Netherlands)

    Heuer, H.; Krögerrecklenfort, E.; Wellington, E.M.H.; Egan, S.; Elsas, van J.D.; Overbeek, van L.S.; Collard, J.M.; Guillaume, G.; Karagouni, A.; Nikolakopoulou, D.; Smalla, K.

    2002-01-01

    A comprehensive multiphasic survey of the prevalence and transfer of gentamicin resistance (Gmr) genes in different non-clinical environments has been performed. We were interested to find out whether Gmr genes described from clinical isolates can be detected in different environmental habitats and

  12. Gene effects for resistance to groundnut rossette disease in exotic ...

    African Journals Online (AJOL)

    The materials were evaluated for biotic and abiotic stresses, but succumbed to groundnut rosette disease (GRD). For these superior lines to find utility in Uganda, they need further improvement by introducing resistance genes to GRD. A study was conducted at NaSARRI to determine nature of gene action controlling ...

  13. Cultivation-dependent and high-throughput sequencing approaches studying the co-occurrence of antibiotic resistance genes in municipal sewage system.

    Science.gov (United States)

    Li, An-Dong; Ma, Liping; Jiang, Xiao-Tao; Zhang, Tong

    2017-11-01

    During the past years, antibiotic-resistant bacteria (ARB) leading for the spreading of antibiotic resistance genes (ARGs) became a global problem, especially multidrug-resistant (MDR) bacteria are considered the prime culprit of antibiotic resistance. However, the correlation between the antibiotic-resistant phenotype and the ARG profiles remains poorly understood. In the present study, metagenomic functional screening and metagenomic analysis of coliforms were combined to explore the phenotype and genotype of the ARBs from municipal sewage. Our results showed that the ARG co-occurrence was widespread in the municipal sewage. The present study also highlighted the high abundance of ARGs from antibiotic resistance coliforms especially the MDR coliforms with ARG level of 33.8 ± 4.2 copies per cell. The ARG profiles and the antibiotic resistance phenotypes of the isolated antibiotic resistant coliforms were also correlated and indicated that the resistance to the related antibiotic (ampicillin, kanamycin, erythromycin, chloramphenicol, and tetracycline) was mostly contributed by the ARGs belonging to the subtypes of β-lactamase, aminoglycoside 3-phosphotransferase, phosphotransferase type 2, chloramphenicol acetyltransferase, tetA, etc.

  14. Transfer patterns of integron-associated and antibiotic resistance genes in S. flexneri during different time intervals in Tianjin, China

    Directory of Open Access Journals (Sweden)

    J Wang

    2014-01-01

    Full Text Available Background: Shigella is one of the common genera of pathogens responsible for bacterial diarrhoea in humans. According to World Health Organisation (WHO, 800,000-1,700,000 patients in China were infected with Shigella spp. in 2000, and Shigella flexneri is the most common serotype (86%. Objectives: We investigated the transfer patterns of integron-associated and antibiotic resistance genes in S. flexneri during different time intervals in the city of Tianjin in the People′s Republic of China. Materials and Methods: The integrase-encoding and variable regions of the integrons of the bacterial strains were amplified by polymerase chain reaction (PCR, followed by gene sequencing. Fifty-six S. flexneri strains, 32 of which were stored in our laboratory and the other 24 were isolated from tertiary hospitals in Tianjin during different time intervals, were tested for their sensitivity to 12 antibiotics by using the Kirby-Bauer antibiotic testing method (K-B method. Results and Conclusion: Of the 32 strains of S. flexneri isolated from 1981 to 1983 and stored in our laboratory, class 1 integron was detected in 28 strains (87.50%, while 27 strains (84.37% harboured an aminoglycoside resistance gene, aadA, in the variable region of their integrons. Class 1 integron was identified in 22 (91.67% of the 24 S. flexneri strains isolated from 2009 to 2010, whereas the variable region and 3′-end amplification were not present in any of the strains. Class 2 integron was not found in the 1981-1983 group (group A of strains; although 19 (79.17% of the 24 strains in the 2009-2010 group (group B possessed class 2 integron, and the variable region of the integron harboured dfrA1 + sat1 + aadA1 genes, which, respectively, mediate antibiotic resistance to trimethoprim, streptothricin and streptomycin. Seventeen strains of the total 56 possessed both class 1 and 2 integrons. Strains belonging to group A were highly resistant to tetracycline, chloramphenicol and a

  15. Scab resistance in 'Geneva' apple is conditioned by a resistance gene cluster with complex genetic control.

    Science.gov (United States)

    Bastiaanse, Héloïse; Bassett, Heather C M; Kirk, Christopher; Gardiner, Susan E; Deng, Cecilia; Groenworld, Remmelt; Chagné, David; Bus, Vincent G M

    2016-02-01

    Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant-pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although 'Geneva' apple was recognized long ago as a potential source of resistance to scab, this resistance has not been characterized previously. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in 'Geneva'. The 17 chromosomes of apple were screened using genotyping-by-sequencing, as well as single marker mapping, to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine mapped a 5-cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of 'Golden Delicious' containing nine candidate nucleotide-binding site leucine-rich repeat (NBS-LRR) resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by 'Geneva', as well as the gene-for-gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  16. Genes involved in novel adaptive aluminum resistance in Rhodotorula glutinis.

    Science.gov (United States)

    Tani, Akio; Kawahara, Takaya; Yamamoto, Yoko; Kimbara, Kazuhide; Kawai, Fusako

    2010-05-01

    Rhodotorula glutinis IFO1125 acquired increased aluminum (Al) resistance from 50 muM to more than 5 mM by repetitive culturing with stepwise increases in Al concentration at pH 4.0. In our previous study we performed differential display to find that three genes (RgFET3, RgGET3, and RgCMK) encoding proteins homologous to Saccharomyces cerevisiae FET3p, GET3p, and CMK1p and CMK2p, respectively, were up-regulated in the Al-resistant cells. In this study we cloned these genes and found they were indeed up-regulated in Al-resistant strains. The cloned genes were introduced into S. cerevisiae and corresponding mutants to test their relevance to Al resistance. The introduction of RgFET3 and RgGET3 conferred Al resistance to the host, but that of RgCMK did not. Green fluorescent protein (GFP)-tagged RgFet3p was localized at the cell periphery in the host. GFP-tagged RgGet3p formed more punctate bodies in the host under Al stress than in the absence of Al. Different growth responses to Fe (III), Cu (II), Ca ions, and cyclosporin A in the wild type and resistant cells of R. glutinis suggested the involvement and possible links of the three genes in Al resistance. (c) 2009. Published by Elsevier B.V.

  17. [Integrons and resistance gene cassettes: structure and role against antimicrobials].

    Science.gov (United States)

    González, Gerardo; Mella, Sergio; Zemelman, Raúl; Bello, Helia; Domínguez, Mariana

    2004-05-01

    Bacteria have developed sophisticated and successful genetic mechanisms to evade the action of antimicrobials. Bacterial multiresistance has caused serious problems in the treatment of nosocomial infections. Integrons and gene cassettes are considered the main genetic elements in the evolution of plasmids and transposons that actively participate in the mobilization of genes, codifying different bacterial resistance mechanisms. This article reviews the historical and structural aspects of integrons and resistance gene cassettes and the presence of these structures in gram negative bacteria isolated from Chilean hospitals in the last ten years.

  18. Frequency of Drug Resistance Gene Amplification in Clinical Leishmania Strains

    Directory of Open Access Journals (Sweden)

    C. Mary

    2010-01-01

    Full Text Available Experimental studies about Leishmania resistance to metal and antifolates have pointed out that gene amplification is one of the main mechanisms of drug detoxification. Amplified genes code for adenosine triphosphate-dependent transporters (multidrug resistance and P-glycoproteins P, enzymes involved in trypanothione pathway, particularly gamma glutamyl cysteine synthase, and others involved in folates metabolism, such as dihydrofolate reductase and pterine reductase. The aim of this study was to detect and quantify the amplification of these genes in clinical strains of visceral leishmaniasis agents: Leishmania infantum, L. donovani, and L. archibaldi. Relative quantification experiments by means of real-time polymerase chain reaction showed that multidrug resistance gene amplification is the more frequent event. For P-glycoproteins P and dihydrofolate reductase genes, level of amplification was comparable to the level observed after in vitro selection of resistant clones. Gene amplification is therefore a common phenomenon in wild strains concurring to Leishmania genomic plasticity. This finding, which corroborates results of experimental studies, supports a better understanding of metal resistance selection and spreading in endemic areas.

  19. Identifying resistance gene analogs associated with resistances to different pathogens in common bean.

    Science.gov (United States)

    López, Camilo E; Acosta, Iván F; Jara, Carlos; Pedraza, Fabio; Gaitán-Solís, Eliana; Gallego, Gerardo; Beebe, Steve; Tohme, Joe

    2003-01-01

    ABSTRACT A polymerase chain reaction approach using degenerate primers that targeted the conserved domains of cloned plant disease resistance genes (R genes) was used to isolate a set of 15 resistance gene analogs (RGAs) from common bean (Phaseolus vulgaris). Eight different classes of RGAs were obtained from nucleotide binding site (NBS)-based primers and seven from not previously described Toll/Interleukin-1 receptor-like (TIR)-based primers. Putative amino acid sequences of RGAs were significantly similar to R genes and contained additional conserved motifs. The NBS-type RGAs were classified in two subgroups according to the expected final residue in the kinase-2 motif. Eleven RGAs were mapped at 19 loci on eight linkage groups of the common bean genetic map constructed at Centro Internacional de Agricultura Tropical. Genetic linkage was shown for eight RGAs with partial resistance to anthracnose, angular leaf spot (ALS) and Bean golden yellow mosaic virus (BGYMV). RGA1 and RGA2 were associated with resistance loci to anthracnose and BGYMV and were part of two clusters of R genes previously described. A new major cluster was detected by RGA7 and explained up to 63.9% of resistance to ALS and has a putative contribution to anthracnose resistance. These results show the usefulness of RGAs as candidate genes to detect and eventually isolate numerous R genes in common bean.

  20. Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, Kira S. [National Center for Biotechnology Information; Omelchenko, Marina [National Center for Biotechnology Information; Gaidamakova, Elena [Uniformed Services University of the Health Sciences (USUHS); Matrosova, Vera [Uniformed Services University of the Health Sciences (USUHS); Vasilenko, Alexander [Uniformed Services University of the Health Sciences (USUHS); Zhai, Min [Uniformed Services University of the Health Sciences (USUHS); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Kim, Edwin [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Pitluck, Samual [U.S. Department of Energy, Joint Genome Institute; Richardson, P M [U.S. Department of Energy, Joint Genome Institute; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Brettin, Tom [Los Alamos National Laboratory (LANL); Saunders, Elizabeth H [Los Alamos National Laboratory (LANL); Lai, Barry [Argonne National Laboratory (ANL); Ravel, Bruce [Argonne National Laboratory (ANL); Kemner, Kenneth M [Argonne National Laboratory (ANL); Wolf, Yuri [National Center for Biotechnology Information; Sorokin, Alexei [Genetique Microbienne; Gerasimova, Anna [Research Institute of Genetics and Selection of Industrial Microorganisms, Mosco; Gelfand, Mikhail [Moscow State University; Fredrickson, James K [Pacific Northwest National Laboratory (PNNL); Koonin, Eugene [National Center for Biotechnology Information; Daly, Michael [Uniformed Services University of the Health Sciences (USUHS)

    2007-01-01

    Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at its optimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and contribute to

  1. Deinococcus geothermalis: The Pool of Extreme Radiation Resistance Genes Shrinks

    Energy Technology Data Exchange (ETDEWEB)

    Makarova, Kira S.; Omelchenko, Marina V.; Gaidamakova, Elena K.; Matrosova, Vera Y.; Vasilenko, Alexander; Zhai, Min; Lapidus, Alla; Copeland, Alex; Kim, Edwin; Land, Miriam; Mavrommatis, Konstantinos; Pitluck, Samuel; Richardson, Paul M.; Detter, Chris; Brettin, Thomas; Saunders, Elizabeth; Lai, Barry; Ravel, Bruce; Kemner, Kenneth M.; Wolf, Yuri I.; Sorokin, Alexander; Gerasimova, Anna V.; Gelfand, Mikhail S.; Fredrickson, James K.; Koonin, Eugene V.; Daly, Michael J.

    2007-07-24

    Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR), ultraviolet light (UV) and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at itsoptimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and contribute to

  2. Deinococcus geothermalis: the pool of extreme radiation resistance genes shrinks.

    Directory of Open Access Journals (Sweden)

    Kira S Makarova

    2007-09-01

    Full Text Available Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation (IR, ultraviolet light (UV and desiccation. The mesophile Deinococcus radiodurans was the first member of this group whose genome was completely sequenced. Analysis of the genome sequence of D. radiodurans, however, failed to identify unique DNA repair systems. To further delineate the genes underlying the resistance phenotypes, we report the whole-genome sequence of a second Deinococcus species, the thermophile Deinococcus geothermalis, which at its optimal growth temperature is as resistant to IR, UV and desiccation as D. radiodurans, and a comparative analysis of the two Deinococcus genomes. Many D. radiodurans genes previously implicated in resistance, but for which no sensitive phenotype was observed upon disruption, are absent in D. geothermalis. In contrast, most D. radiodurans genes whose mutants displayed a radiation-sensitive phenotype in D. radiodurans are conserved in D. geothermalis. Supporting the existence of a Deinococcus radiation response regulon, a common palindromic DNA motif was identified in a conserved set of genes associated with resistance, and a dedicated transcriptional regulator was predicted. We present the case that these two species evolved essentially the same diverse set of gene families, and that the extreme stress-resistance phenotypes of the Deinococcus lineage emerged progressively by amassing cell-cleaning systems from different sources, but not by acquisition of novel DNA repair systems. Our reconstruction of the genomic evolution of the Deinococcus-Thermus phylum indicates that the corresponding set of enzymes proliferated mainly in the common ancestor of Deinococcus. Results of the comparative analysis weaken the arguments for a role of higher-order chromosome alignment structures in resistance; more clearly define and substantially revise downward the number of uncharacterized genes that might participate in DNA repair and

  3. RESISTANCE-RELATED GENE TRANSCRIPTION AND ...

    African Journals Online (AJOL)

    jdx

    2014-02-05

    Feb 5, 2014 ... fast- and delayed-acting Mla powdery mildew resistance alleles. Mol. Plant Microb. In. 19: 939-947. Chen RT, Zhu XC, Wang ZF (1997). A report of investigating and studying tobacco infectious diseases of 16 main tobacco producing provinces (regions) in China. Chinese Tobacco Science 4:1-7 (in.

  4. Tetracycline ulcers of the oesophagus

    Energy Technology Data Exchange (ETDEWEB)

    Winckler, K.

    1981-11-01

    Two cases of tetracycline ulcers of the oesophagus are reported and compared with thirteen other cases from the literature. In most cases, the patients had taken their capsules with little or no fluid just before going to bed. Some hours later they developed retrosternal pain that was intensified by swallowing. Endoscopy showed sharply demarcated greyish-white areas of mucosal damage which represented layers of stratified squamous cells, separated by oedema, and a dense neutrophilic infiltration of the lamina propria and the muscularis mucosa. Roentgenology was unsuitable to detect the lesions. They healed without complications within one to six weeks. Prolonged retention of the capsules in the oesophagus is thought to cause the mucosal damage. Patients on oral tetracycline or doxycycline treatment should therefore be instructed to take their capsules with a meal or with copious water and not just before going to bed.

  5. Molecular Scree ning of Blast Resistance Genes in Rice Germplasms Resistant to Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Liang Yan

    2017-01-01

    Full Text Available Molecular screening of major rice blast resistance genes was determined with molecular markers, which showed close-set linkage to 11 major rice blast resistance genes (Pi-d2, Pi-z, Piz-t, Pi-9, Pi-36, Pi-37, Pi5, Pi-b, Pik-p, Pik-h and Pi-ta2, in a collection of 32 accessions resistant to Magnaporthe oryzae. Out of the 32 accessions, the Pi-d2 and Pi-z appeared to be omnipresent and gave positive express. As the second dominant, Pi-b and Piz-t gene frequencies were 96.9% and 87.5%. And Pik-h and Pik-p gene frequencies were 43.8% and 28.1%, respectively. The molecular marker linkage to Pi-ta2 produced positive bands in eleven accessions, while the molecular marker linkage to Pi-36 and Pi-37 in only three and four accessions, respectively. The natural field evaluation analysis showed that 30 of the 32 accessions were resistant, one was moderately resistant and one was susceptible. Infection types were negatively correlated with the genotype scores of Pi-9, Pi5, Pi-b, Pi-ta2 and Pik-p, although the correlation coefficients were very little. These results are useful in identification and incorporation of functional resistance genes from these germplasms into elite cultivars through marker-assisted selection for improved blast resistance in China and worldwide.

  6. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA

    Directory of Open Access Journals (Sweden)

    Bertinellys TEIXEIRA

    2016-01-01

    Full Text Available The enzymatic modification of aminoglycosides by aminoglycoside-acetyltransferases (AAC, aminoglycoside-adenyltransferases (AAD, and aminoglycoside-phosphotransferases (APH, is the most common resistance mechanism in P. aeruginosa and these enzymes can be coded on mobile genetic elements that contribute to their dispersion. One hundred and thirty seven P. aeruginosa isolates from the University Hospital, Cumana, Venezuela (HUAPA were evaluated. Antimicrobial susceptibility was determined by the disk diffusion method and theaac, aadB and aph genes were detected by PCR. Most of the P. aeruginosa isolates (33/137 were identified from the Intensive Care Unit (ICU, mainly from discharges (96/137. The frequency of resistant P. aeruginosaisolates was found to be higher for the aminoglycosides tobramycin and amikacin (30.7 and 29.9%, respectively. Phenotype VI, resistant to these antibiotics, was the most frequent (14/49, followed by phenotype I, resistant to all the aminoglycosides tested (12/49. The aac(6´-Ib,aphA1 and aadB genes were the most frequently detected, and the simultaneous presence of several resistance genes in the same isolate was demonstrated. Aminoglycoside resistance in isolates ofP. aeruginosa at the HUAPA is partly due to the presence of the aac(6´-Ib, aphA1 andaadB genes, but the high rates of antimicrobial resistance suggest the existence of several mechanisms acting together. This is the first report of aminoglycoside resistance genes in Venezuela and one of the few in Latin America.

  7. Fate and removal of various antibiotic resistance genes in typical pharmaceutical wastewater treatment systems.

    Science.gov (United States)

    Zhai, Wenchao; Yang, Fengxia; Mao, Daqing; Luo, Yi

    2016-06-01

    The high levels of antibiotic residues in pharmaceutical wastewater treatment plants (PWWTPs) make these plants the hotspots for the proliferation of antibiotic resistance genes (ARGs). This study investigated the fate and removal of 11 ARG subtypes for sulfonamide, tetracycline, β-lactam, and macrolide resistance in each processing stage of two full-scale PWWTPs in northern China. The levels of typical ARG subtypes in the final effluents ranged from (2.56 ± 0.13) × 10(1) to (2.36 ± 0.11) × 10(7) copies/ml. The absolute abundance of ARGs in effluents accounted for only 0.03-78.1 % of influents of the two PWWTPs, while the majority of the ARGs were transported to the dewatered sludge with concentrations from (2.65 ± 0.43) × 10(5) to (4.27 ± 0.03) × 10(10) copies/g dry weight (dw). The total loads of ARGs discharged through dewatered sludge plus effluent was 1.01-14.09-fold higher than that in the raw influents, suggesting the proliferation of ARGs occurred in the wastewater treatment. The proliferation of ARGs mainly occurs in biological treatment process, such as aeration tank, anoxic tank, sequencing batch reactor (SBR), and bio-contact oxidation, facilitates the proliferation of various ARGs, implying significant replication of certain ARG subtypes may be attributable to microbial growth. Chemical oxidation seems promising to remove ARGs, with removal efficiency ranged from 29.3 to 85.7 %, while the partial correlation analysis showed significant correlations between antibiotic concentration and ARG removal. Thus, the high antibiotic residues within the PWWTPs may have an influence on the proliferation, fate, and removal of the associated ARG subtypes.

  8. Antibiotic Resistance Gene Abundances Associated with Waste Discharges to the Almendares River near Havana, Cuba

    Science.gov (United States)

    2010-01-01

    Considerable debate exists over the primary cause of increased antibiotic resistance (AR) worldwide. Evidence suggests increasing AR results from overuse of antibiotics in medicine and therapeutic and nontherapeutic applications in agriculture. However, pollution also can influence environmental AR, particularly associated with heavy metal, pharmaceutical, and other waste releases, although the relative scale of the “pollution” contribution is poorly defined, which restricts targeted mitigation efforts. The question is “where to study and quantify AR from pollution versus other causes to best understand the pollution effect”. One useful site is Cuba because industrial pollution broadly exists; antibiotics are used sparingly in medicine and agriculture; and multiresistant bacterial infections are increasing in clinical settings without explanation. Within this context, we quantified 13 antibiotic resistance genes (ARG; indicators of AR potential), 6 heavy metals, 3 antibiotics, and 17 other organic pollutants at 8 locations along the Almendares River in western Havana at sites bracketing known waste discharge points, including a large solid waste landfill and various pharmaceutical factories. Significant correlations (p < 0.05) were found between sediment ARG levels, especially for tetracyclines and β-lactams (e.g., tet(M), tet(O), tet(Q), tet(W), blaOXA), and sediment Cu and water column ampicillin levels in the river. Further, sediment ARG levels increased by up to 3 orders of magnitude downstream of the pharmaceutical factories and were highest where human population densities also were high. Although explicit links are not shown, results suggest that pollution has increased background AR levels in a setting where other causes of AR are less prevalent. PMID:21133405

  9. Detection of Class 1 and 2 Integrons, β-Lactamase Genes and Molecular Characterization of Sulfonamide Resistance in Escherichia coli Isolates Recovered from Poultry in China

    Directory of Open Access Journals (Sweden)

    Jam Kashif§, Rehana Buriro§, Javed Memon, Muhammad Yaqoob, Jamila Soomro§, Diao Dongxue, Huang Jinhu and Wang Liping*

    2013-07-01

    Full Text Available This study aimed to detect integrons, β-lactamase genes and to characterize sulfonamide resistant E. coli isolates recovered from poultry. All the isolates (n=38 were investigated for the presence of integrons, Sul1, Sul2, Sul3 genes by PCR. Class 1 and class 2 integron were present in 79 and 16%, respectively. Additional resistance gene cassette embedded in class 1 and 2 integrons was aadA1, aadA5, dfrA17 and aadA22, dfrA, respectively. Sul1 and Sul2 genes were detected in 42.1 and 60.5% isolates, respectively. Both the Sul1 and Sul2 were present in 23% isolates. However, Sul3 gene was not present. Co-existence of Sul1 and Sul2 with class 1 integrons was found in 28.9 and 60.5% of class 1 integron positive isolates, respectively. Whereas, a less percentage of isolates showed a low level of resistance to β-lactams and no blaCTX-M, blaSHV and blaTEM was found. The MIC results showed resistance to sulfadiazine and sulfamethoxazole-trimethoprim in 88 and 84% isolates, resistance to penicillin, ampicillin, amoxicillin was 52, 52 and 44%, respectively. Chloramphenicol, florfenicol, tetracycline and gentamycin resistance was found in 51, 5, 42 and 67% isolates, respectively. This study revealed high frequency of class 1 integrons, Sul genes among poultry E. coli isolates, therefore further spread of Sul genes and integrons is predictable.

  10. Effects of biochar on reducing the abundance of oxytetracycline, antibiotic resistance genes, and human pathogenic bacteria in soil and lettuce.

    Science.gov (United States)

    Duan, Manli; Li, Haichao; Gu, Jie; Tuo, Xiaxia; Sun, Wei; Qian, Xun; Wang, Xiaojuan

    2017-05-01

    Antibiotics and antibiotic resistance genes (ARGs) in soil can affect human health via the food chain. Biochar is a soil amendment but its impacts on ARGs and the microbial communities associated with soil and vegetables are unclear. Therefore, we established three lettuce pot culture experiments, i.e., O300: 300 mg/kg oxytetracycline (OTC), BO300: 300 mg/kg OTC + 2% biochar, and a control without OTC or biochar. We found that under BO300, the relative abundances of ARGs were reduced by 51.8%, 43.4%, and 44.1% in lettuce leaves, roots, and soil, respectively, compared with O300. intI1 was highly abundant in soil and lettuce, and it co-occurred with some ARGs (tetW, ermF, and sul1). Redundancy analysis and network analysis indicated that the bacterial community succession was the main mechanism that affected the variations in ARGs and intI1. The reduction of Firmicutes due to the biochar treatment of soil and lettuce was the main factor responsible for the removal of tetracycline resistance genes in leaves. Biochar application led to the disappearance of human pathogenic bacteria (HPB), which was significantly correlated with the abundances of ermF and ermX. In summary, biochar is an effective farmland amendment for reducing the abundances of antibiotics, ARGs, and HPB in order to ensure the safety of vegetables and protect human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. RMo1 confers blast resistance in barley and is located within the complex of resistance genes containing Mla, a powdery mildew resistance gene.

    Science.gov (United States)

    Inukai, Tsuyoshi; Vales, M Isabel; Hori, Kiyosumi; Sato, Kazuhiro; Hayes, Patrick M

    2006-09-01

    Isolates of Magnaporthe oryzae (the causal agent of rice blast disease) can infect a range of grass species, including barley. We report that barley Hordeum vulgare cv. Baronesse and an experimental line, BCD47, show a range of resistance reactions to infection with two rice blast isolates. The complete resistance of Baronesse to the isolate Ken 54-20 is controlled by a single dominant gene, designated RMo1. RMo1 mapped to the same linkage map position on chromosome 1H as the powdery mildew resistance locus Mla and an expressed sequence tag (k04320) that corresponds to the barley gene 711N16.16. A resistance quantitative trait locus (QTL), at which Baronesse contributed the resistance allele, to the isolate Ken 53-33 also mapped at the same position as RMo1. Synteny analysis revealed that a corresponding region on rice chromosome 5 includes the bacterial blight resistance gene xa5. These results indicate that a defined region on the short arm of barley chromosome 1H, including RMo1 and Mla, harbors genes conferring qualitative and quantitative resistance to multiple pathogens. The partial resistance of BCD47 to Ken53-33 is determined by alleles at three QTL, two of which coincide with the linkage map positions of the mildew resistance genes mlo and Mlf.

  12. Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam.

    Science.gov (United States)

    Lien, La Thi Quynh; Lan, Pham Thi; Chuc, Nguyen Thi Kim; Hoa, Nguyen Quynh; Nhung, Pham Hong; Thoa, Nguyen Thi Minh; Diwan, Vishal; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia

    2017-06-29

    The environmental spread of antibiotic-resistant bacteria has been recognised as a growing public health threat for which hospitals play a significant role. The aims of this study were to investigate the prevalence of antibiotic resistance and antibiotic resistance genes (ARGs) in Escherichia coli isolates from hospital wastewater in Vietnam. Wastewater samples before and after treatment were collected using continuous sampling every month over a year. Standard disk diffusion and E-test were used for antibiotic susceptibility testing. Extended-spectrum beta-lactamase (ESBL) production was tested using combined disk diffusion. ARGs were detected by polymerase chain reactions. Resistance to at least one antibiotic was detected in 83% of isolates; multidrug resistance was found in 32%. The highest resistance prevalence was found for co-trimoxazole (70%) and the lowest for imipenem (1%). Forty-three percent of isolates were ESBL-producing, with the bla TEM gene being more common than bla CTX-M . Co-harbouring of the bla CTX-M , bla TEM and qepA genes was found in 46% of isolates resistant to ciprofloxacin. The large presence of antibiotic-resistant E. coli isolates combined with ARGs in hospital wastewater, even post-treatment, poses a threat to public health. It highlights the need to develop effective processes for hospital wastewater treatment plants to eliminate antibiotic resistant bacteria and ARGs.

  13. Virus-induced gene silencing of Mlo genes induces powdery mildew resistance in Triticum aestivum.

    Science.gov (United States)

    Várallyay, Eva; Giczey, Gábor; Burgyán, József

    2012-07-01

    Powdery mildew is one of the most important cereal diseases worldwide. Genetic analysis has revealed that mutant alleles of the Mlo gene cause broad-spectrum resistance against this pathogen in barley. In this study, the possibility of inducing broad-spectrum powdery mildew resistance against this pathogen by RNAi of the barley Mlo ortholog in wheat was examined using virus-induced gene silencing (VIGS). A clear correlation was found between resistance and accumulation of Mlo-specific siRNAs, raising the possibility of designing powdery mildew resistance in wheat by RNA silencing using both transgenic and non-transgenic approaches.

  14. Echinoderms from Azores islands: an unexpected source of antibiotic resistant Enterococcus spp. and Escherichia coli isolates.

    Science.gov (United States)

    Marinho, Catarina; Silva, Nuno; Pombo, Sofia; Santos, Tiago; Monteiro, Ricardo; Gonçalves, Alexandre; Micael, Joana; Rodrigues, Pedro; Costa, Ana Cristina; Igrejas, Gilberto; Poeta, Patrícia

    2013-04-15

    The prevalence of antibiotic resistance and the implicated mechanisms of resistance were evaluated in Enterococcus spp. and Escherichia coli, isolated from a total of 250 faecal samples of echinoderms collected from Azorean waters (Portugal). A total of 144 enterococci (120 Enterococcus faecium, 14 E. hirae, 8 E. faecalis, 2 E. gallinarum) and 10 E. coli were recovered. High percentages of resistance in enterococci were found for erythromycin, ampicillin, tetracyclin and ciprofloxacin. The erm(A) or erm(B), tet(M) and/or tet(L), vat(D), aac(6')-aph(2″) and aph(3')-IIIa genes were found in isolates resistant to erythromycin, tetracycline, quinupristin/dalfopristin, high-level gentamicin and high-level kanamycin, respectively. Resistance in E. coli isolates was detected for streptomycin, amikacin, tetracycline and tobramycin. The aadA gene was found in streptomycin-resistant isolates and tet(A)+tet(B) genes in tetracycline-resistant isolates. The data recovered are essential to improve knowledge about the dissemination of resistant strains through marine ecosystems and the possible implications involved in transferring these resistances either to other animals or to humans. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Monitoring and evaluation of antibiotic resistance genes in four municipal wastewater treatment plants in Harbin, Northeast China.

    Science.gov (United States)

    Wen, Qinxue; Yang, Lian; Duan, Ruan; Chen, Zhiqiang

    2016-05-01

    The development and proliferation of antibiotic resistance in pathogenic and environmental microorganisms is of great concern for public health. In this study, the distribution and removal efficiency of intI1 and eight subtypes of antibiotic resistance genes (ARGs) for tetracycline, sulfonamides, beta-lactams resistance in four municipal wastewater treatment plants (WWTPs) in Harbin, which locates in Songhua River basin in cold areas of China, were monitored by real-time fluorescent quantitative PCR. The results showed that intI1 and 6 ARGs except for blaTEM and blaSHV were detected in wastewater and sludge samples and 0.3-2.7 orders of magnitude of ARGs removal efficiency in the four WWTPs were observed. The investigation on the removal of ARGs of different treatment units in one WWTP showed that the biological treatment unit played the most important role in ARGs removal (1.2-1.8 orders of magnitude), followed by UV disinfection, while primary physical treatment units can hardly remove any ARGs. Although all the WWTPs can remove ARGs effectively, ARGs concentrations are still relatively high in the effluent, their further attenuation should be investigated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. IncP-1ε plasmids are important vectors of antibiotic resistance genes in agricultural systems: diversification driven by class 1 integron gene cassettes

    Directory of Open Access Journals (Sweden)

    Holger eHeuer

    2012-01-01

    Full Text Available The role of broad host range IncP-1ε plasmids in the dissemination of antibiotic resistance in agricultural systems has not yet been investigated. These plasmids were detected in total DNA from all of 16 manure samples and in arable soil based on a novel 5’-nuclease assay for real time PCR. A correlation between IncP-1ε plasmid abundance and antibiotic usage was revealed. In a soil microcosm experiment the abundance of IncP-1ε plasmids was significantly increased even 127 days after application of manure containing the antibiotic compound sulfadiazine, compared to soil receiving only manure, only sulfadiazine, or water. Fifty IncP-1ε plasmids that were captured in E. coli CV601gfp from bacterial communities of manure and arable soil were characterized by PCR and hybridisation. All plasmids carried class 1 integrons with highly varying sizes of the gene cassette region and the sul1 gene. Three IncP-1ε plasmids captured from soil bacteria and one from manure were completely sequenced. The backbones were nearly identical to that of the previously described IncP-1ε plasmid pKJK5. The plasmids differed mainly in the composition of a Tn402-like transposon carrying a class 1 integron with varying gene cassettes, IS1326, and in three of the plasmids the tetracycline resistance transposon Tn1721 with various truncations. Diverse Beta- and Gammaproteobacteria were revealed as hosts of one of the IncP-1ε plasmids in soil microcosms. Our data suggest that IncP-1ε plasmids are important vectors for horizontal transfer of antibiotic resistance in agricultural systems.

  17. Spectrum of Resistance Conferred by ml-o Powdery Mildew Resistance Genes in Barley

    DEFF Research Database (Denmark)

    Jørgensen, Jørgen Helms

    1977-01-01

    /(4) in all tests. They were also resistant to field populations of the pathogen when scored in disease nurseries at more than 78 locations in 29 countries in Europe, the Near East, North and South America. New Zealand, and Japan. This indicates that the 11 genes confer the same, world-wide spectrum......Ten barley mutants and five Ethiopian barley lines representing 11 independently arisen powdery mildew resistance genes in the ml-o locus were tested at the seedling stage to cultures of the powdery mildew fungus from Europe, Israel, USA. Canada, and Japan. They were resistant with infection type 0...

  18. vestigial suppressor genes and resistance to aminopterin in Drosophila melanogaster.

    Science.gov (United States)

    Bazin, C; Silber, J

    1992-11-01

    We have shown that the vestigial (vg) mutant of D. melanogaster has a perturbed nucleotide metabolism compared to various wild-type strains. The mutant is particularly spontaneously resistant to aminopterin. The resistance seems to correlate with an increase in dihydrofolate reductase (DHFR) activity and quantity. The DHRF is a target enzyme of aminopterin. Our results suggest that the vg+ gene could be a regulatory gene acting on the DHFR gene. The wing mutant phenotype being due to a decrease in the thymidylate pool (dTMP) (Silber et al., 1989). In order to understand better the action of the mutant gene on nucleotide metabolism, we have induced suppressor genes of the mutant phenotype by mutagenesis with ethyl methanesulfonate (EMS) and bromouridine (BUR). The suppressor strains obtained display a phenotype intermediate between wild-type and vg phenotype. The action of three independent suppressor genes on eight parameters of nucleotide metabolism is reported here [three enzyme activities, resistance to aminopterin and to fluorodeoxyuridine (FUdR), auxotrophy test and the ability to use exogenous thymidine and uridine]. In comparison to the original vg strain, major changes for the parameters tested are observed. The most striking effects are obtained with the vgBUR27 strain, which is highly sensitive to aminopterin and to fluorodeoxyuridine and didplas the highest thymidine kinase (TK) and DHFR activities within the strains tested. The potential actions of suppressor genes on the vg mutant are discussed.

  19. Gene interactions and genetics of blast resistance and yield ...

    Indian Academy of Sciences (India)

    Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1, F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 ...

  20. Gene expression in pyriproxyfen-resistant Bemisia tabaci Q biotype.

    Science.gov (United States)

    Ghanim, Murad; Kontsedalov, Svetlana

    2007-08-01

    Pyriproxyfen is a biorational insecticide that acts as a juvenile hormone (JH) analogue and disrupts insect development with an unknown molecular mode of action. Pyriproxyfen is one of the major insecticides used to control the whitefly Bemisia tabaci (Gennadius) and comply with integrated pest management (IPM) programmes, resulting in minimal effects on the environment, humans and beneficial organisms. During the last few years, resistance to pyriproxyfen has been observed in several locations in Israel, sometimes reaching a thousandfold or more. No information exists about the molecular basis underlying this resistance that may lead to understanding the mode of action of pyriproxyfen and developing molecular markers for rapid monitoring of resistance outbreaks. In this communication, a cDNA microarray from B. tabaci was used to monitor changes in gene expression in a resistant B. tabaci population. Based on statistical analysis, 111 expressed sequence tags (ESTs) were identified that were differentially upregulated in the resistant strain after pyriproxyfen treatment. Many of the upregulated ESTs observed in the present study belong to families usually associated with resistance and xenobiotic detoxification such as mitochondrial genes, P450s and oxidative stress, genes associated with protein, lipid and carbohydrate metabolism and others related to JH-associated processes in insects such as oocyte and egg development. Copyright (c) 2007 Society of Chemical Industry

  1. Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

    Directory of Open Access Journals (Sweden)

    Masayoshi Hashimoto

    2016-10-01

    Full Text Available The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species.

  2. Low prevalence of antibiotic-resistant gram-negative bacteria ...

    African Journals Online (AJOL)

    2009-01-13

    Jan 13, 2009 ... detection of tetracycline resistance genes [tet(A), tet(B), tet(C), tet(D), tet(E), tet(G) and tet(M)]; macrolide or combinations of. TABLE 1. List of oligonucleotide primers used in this study. Resistance. Primer. Sequence (5′ → 3′). Amplicon. Reference gene name size (bp) ere(A). ereA-fw. TCA CTG GCT AGA ...

  3. Mapping of common bunt resistance gene Bt9 in wheat.

    Science.gov (United States)

    Steffan, Philipp Matthias; Torp, Anna Maria; Borgen, Anders; Backes, Gunter; Rasmussen, Søren K

    2017-05-01

    The Bt9 resistance locus was mapped and shown to be distinct from the Bt10 locus. New markers linked to Bt9 have been identified and may be used to breed for resistance towards the seed-borne disease. Increasing organic wheat production in Denmark, and in other wheat-producing areas, in conjunction with legal requirements for organic seed production, may potentially lead to a rise in common bunt occurrence. As systemic pesticides are not used in organic farming, organic wheat production systems may benefit from genetic resistances. However, little is known about the underlying genetic mechanisms and locations of the resistance factors for common bunt resistance in wheat. A double haploid (DH) population segregating for common bunt resistance was used to identify the chromosomal location of common bunt resistance gene Bt9. DH lines were phenotyped in three environments and genotyped with DArTseq and SSR markers. The total length of the resulting linkage map was 2882 cM distributed across all 21 wheat chromosomes. Bt9 was mapped to the distal end of chromosome 6DL. Since wheat common bunt resistance gene Bt10 is also located on chromosome 6D, the possibility of their co-location was investigated. A comparison of marker sequences linked to Bt9 and Bt10 on physical maps of chromosome 6D confirmed that Bt9 and Bt10 are two distinct resistance factors located at the distal (6DL) and proximal (6DS) end, respectively, of chromosome 6D. Five new SSR markers Xgpw4005-1, Xgpw7433, Xwmc773, Xgpw7303 and Xgpw362 and many SNP and PAV markers flanking the Bt9 resistance locus were identified and they may be used in the future for marker-assisted selection.

  4. Tagging of resistance gene(s) to rhizomania disease in sugar beet ...

    African Journals Online (AJOL)

    The rhizomania disease is one of the most important diseases in Iran and some other parts of the world which potentially could play a role in decreasing sugar yield in fields. One approach to combat with this disease is the use of resistance varieties. This varieties have been identified which are having resistance genes to ...

  5. The R1 gene for potato resistance to late blight (Phytophthora infestans) belongs to the leucine zipper/NBS/LRR class of plant resistance genes.

    Science.gov (United States)

    Ballvora, Agim; Ercolano, Maria Raffaella; Weiss, Julia; Meksem, Khalid; Bormann, Christina Angelika; Oberhagemann, Petra; Salamini, Francesco; Gebhardt, Christiane

    2002-05-01

    Late blight caused by the oomycete Phytophthora infestans is the most destructive disease in potato cultivation worldwide. New, more virulent P. infestans strains have evolved which overcome the genetic resistance that has been introgressed by conventional breeding from wild potato species into commercial varieties. R genes (for single-gene resistance) and genes for quantitative resistance to late blight are present in the germplasm of wild and cultivated potato. The molecular basis of single-gene and quantitative resistance to late blight is unknown. We have cloned R1, the first gene for resistance to late blight, by combining positional cloning with a candidate gene approach. The R1 gene is member of a gene family. It encodes a protein of 1293 amino acids with a molecular mass of 149.4 kDa. The R1 gene belongs to the class of plant genes for pathogen resistance that have a leucine zipper motif, a putative nucleotide binding domain and a leucine-rich repeat domain. The most closely related plant resistance gene (36% identity) is the Prf gene for resistance to Pseudomonas syringae of tomato. R1 is located within a hot spot for pathogen resistance on potato chromosome V. In comparison to the susceptibility allele, the resistance allele at the R1 locus represents a large insertion of a functional R gene.

  6. Multiple herbicide resistance in Lolium multiflorum and identification of conserved regulatory elements of herbicide resistance genes

    Directory of Open Access Journals (Sweden)

    Khalid Mahmood

    2016-08-01

    Full Text Available Herbicide resistance is a ubiquitous challenge to herbicide sustainability and a looming threat to control weeds in crops. Recently four genes were found constituently over-expressed in herbicide resistant individuals of Lolium rigidum, a close relative of L. multiflorum. These include two cytochrome P450s, one nitronate monooxygenase and one glycosyl-transferase. Higher expressions of these four herbicide metabolism related (HMR genes were also observed after herbicides exposure in the gene expression databases, indicating them a reliable marker. In order to get an overview of herbicidal resistance status of Lolium multiflorum L, 19 field populations were collected. Among these populations, four populations were found to be resistant to acetolactate synthase (ALS inhibitors while three exhibited resistance to acetyl-CoA carboxylase (ACCase inhibitors in our initial screening and dose response study. The genotyping showed the presence of mutations Trp-574-Leu and Ile-2041-Asn in ALS and ACCase, respectively and qPCR experiments revealed the enhanced expression of HMR genes in individuals of certain resistant populations. Moreover, co-expression networks and promoter analyses of HMR genes in O.sativa and A.thaliana resulted in the identification of a cis-regulatory motif and zinc finger transcription factors. The identified transcription factors were highly expressed similar to HMR genes in response to xenobiotics whereas the identified motif known to play a vital role in coping with environmental stresses and maintaining genome stability. Overall, our findings provide an important step forward towards a better understanding of metabolism-based herbicide resistance that can be utilized to devise novel strategies of weed management.

  7. Compound list: tetracycline [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available tetracycline TC 00048 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/in_vitro/tetracycline....Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vitro/tetracycline...jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Repeat/tetracycline.Rat.in_vivo.Liver.Repeat.zip ... ....Rat.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Single/tetracycli...ne.Rat.in_vivo.Liver.Single.zip ftp://ftp.biosciencedbc.

  8. Global regulator SoxR is a negative regulator of efflux pump gene expression and affects antibiotic resistance and fitness in Acinetobacter baumannii.

    Science.gov (United States)

    Li, Henan; Wang, Qi; Wang, Ruobing; Zhang, Yawei; Wang, Xiaojuan; Wang, Hui

    2017-06-01

    SoxR is a global regulator contributing to multidrug resistance in Enterobacteriaceae. However, the contribution of SoxR to antibiotic resistance and fitness in Acinetobacter baumannii has not yet been studied. Comparisons of molecular characteristics were performed between 32 multidrug-resistant A. baumannii isolates and 11 susceptible isolates. A soxR overexpression mutant was constructed, and its resistance phenotype was analyzed. The impact of SoxR on efflux pump gene expression was measured at the transcription level. The effect of SoxR on the growth and fitness of A. baumannii was analyzed using a growth rate assay and an in vitro competition assay. The frequency of the Gly39Ser mutation in soxR was higher in multidrug-resistant A. baumannii, whereas the soxS gene was absent in all strains analyzed. SoxR overexpression led to increased susceptibility to chloramphenicol (4-fold), tetracycline (2-fold), tigecycline (2-fold), ciprofloxacin (2-fold), amikacin (2-fold), and trimethoprim (2-fold), but it did not influence imipenem susceptibility. Decreased expression of abeS (3.8-fold), abeM (1.3-fold), adeJ (2.4-fold), and adeG (2.5-fold) were correlated with soxR overexpression (P baumannii.

  9. Occurrence of antibiotic resistance genes and mobile genetic elements in enterococci and genomic DNA during anaerobic digestion of pharmaceutical waste sludge with different pretreatments.

    Science.gov (United States)

    Tong, Juan; Lu, XueTing; Zhang, JunYa; Sui, Qianwen; Wang, Rui; Chen, Meixue; Wei, Yuansong

    2017-07-01

    Pharmaceutical waste sludge harbors large amounts of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), and it is necessary to study the reduction of ARGs and MGEs during sludge treatment. Therefore, the antibiotic resistance phenotypes and genotypes of enterococci, and the ARGs and MGEs in genomic DNA were investigated during anaerobic digestion (AD) with microwave (MW), thermal hydrolysis (TH) and ozone pretreatment. Results showed that sludge pretreatment increased the occurrence of the resistance phenotypes and genotypes of enterococci. During AD, the resistance of enterococci to macrolides decreased, except for in the MW-pretreated sludge. Horizontal gene transfer and co-occurrence of ermB and tetM in enterococci resulted in increased tetracycline resistance of enterococci throughout the sludge treatment. MGEs such as intI1, ISCR1 and Tn916/1545 had a significant effect on the distribution of ARGs. AD with pretreatment, especially TH pretreatment, resulted in greater ARGs and MGEs reduction and improved methane production. Copyright © 2017. Published by Elsevier Ltd.

  10. Whole-Genome Sequences of Two Campylobacter coli Isolates from the Antimicrobial Resistance Monitoring Program in Colombia.

    Science.gov (United States)

    Bernal, Johan F; Donado-Godoy, Pilar; Valencia, María Fernanda; León, Maribel; Gómez, Yolanda; Rodríguez, Fernando; Agarwala, Richa; Landsman, David; Mariño-Ramírez, Leonardo

    2016-03-17

    Campylobacter coli, along with Campylobacter jejuni, is a major agent of gastroenteritis and acute enterocolitis in humans. We report the whole-genome sequences of two multidrug-resistance C. coli strains, isolated from the Colombian poultry chain. The isolates contain a variety of antimicrobial resistance genes for aminoglycosides, lincosamides, fluoroquinolones, and tetracycline. Copyright © 2016 Bernal et al.

  11. Antibiotic resistance and ndvB gene expression among biofilm ...

    African Journals Online (AJOL)

    A novel antibiotic resistant mechanism among biofilms is glucan-mediated sequestration in which ndvB gene encodes a glucosyltransferase involved in the formation of this glucans. We studied the biofilm formation and antibiotic susceptibility pattern of P. aeruginosa isolated from clinical samples, and measured the ...

  12. Resistance-related gene transcription and antioxidant enzyme ...

    African Journals Online (AJOL)

    The two tobacco relatives of Nicotiana alata and Nicotiana longiflora display a high level of resistance against Colletotrichum nicotianae and the two genes NTF6 and NtPAL related to pathogen defense transcription were higher in N. alata and N. longiflora than the commercial cv. K326. Inoculation with C. nicotianae ...

  13. Mapping of stripe rust resistance gene in an Aegilops caudata ...

    Indian Academy of Sciences (India)

    Anonymous 2013 The package of practices for crops of Punjab, rabi. 2013–14. Punjab Agricultural University, Ludhiana, India. Bansal M., Kaur S., Dhaliwal H., Chhuneja P., Bariana H. and. Bansal U. 2016 Introgression of linked rust resistance genes Lr76 and Yr70 from Aegilops umbellulata to wheat chromosome 5DS.

  14. Isolation and characterization of a candidate gene for resistance to ...

    African Journals Online (AJOL)

    The deduced peptide sequence consisted of 920 amino acid residues and shared 97.83% amino acid identity with Cre3. The sequence harbored a signal peptide domain, a nucleotide-binding ARC (NB-ARC) domain, and a leucine-rich repeat (LRR) domain, all of which are typical characteristics of resistance genes.

  15. Absence of meca gene in methicillin-resistant staphylococcus ...

    African Journals Online (AJOL)

    Methicillin-resistant Staphylococcus aureus has emerged as a serious threat to public health, causing both hospital and community-associated infections. The gold standard for MRSA detection is the amplification of the mecA gene that codes for the production of the altered penicillin-binding protein (PBP2a) responsible for ...

  16. Multi-Drug Resistance 1 Genetic Polymorphisms Gene Expression ...

    African Journals Online (AJOL)

    Multi-Drug Resistance 1 Genetic Polymorphisms Gene Expression and Prediction of Chemotherapy Response in Breast Cancer Egyptian Patients. ... C3435 TT and C3435 CT had odds ratio (p-value) 5.6 (<0.001) and 2.28 (0.01) for response to anthracycline-based chemotherapy, respectively, compared to CC genotype.

  17. Molecular Detection of Virulence Genes and Antibiotic Resistance ...

    African Journals Online (AJOL)

    Abstract. Escherichia coli O157:H7 is an important food-borne pathogen that can cause diarrhea, haemorrhagic colitis and haemolytic uremic syndrome. This study was conducted to investigate the prevalence, virulence genes and antibiotic resistance patterns of E. coli. O157:H7 in raw beef meat sold in Abeokuta, South ...

  18. Extraction of differential expressing aphid-resistance genes of ...

    African Journals Online (AJOL)

    Yomi

    2012-01-03

    Jan 3, 2012 ... Key words: Extraction, sorghum, SSH, aphid-resistance genes. INTRODUCTION. Aphids (Order: Homoptera) are major insect pests of the world's agriculture which damage crops by removing photo assimilates and vectoring numerous devastating. *Corresponding author. fenglinsn@126.com,changjinhua ...

  19. Molecular Detection of Virulence Genes and Antibiotic Resistance ...

    African Journals Online (AJOL)

    Escherichia coli O157:H7 is an important food-borne pathogen that can cause diarrhea, haemorrhagic colitis and haemolytic uremic syndrome. This study was conducted to investigate the prevalence, virulence genes and antibiotic resistance patterns of E. coli O157:H7 in raw beef meat sold in Abeokuta, South west Nigeria ...

  20. The impact of insulin resistance, gender, genes, glucocorticoids and ...

    African Journals Online (AJOL)

    2010-11-15

    Nov 15, 2010 ... Review: The impact of insulin resistance, gender, genes, glucocorticoids and ethnicity on body fat distribution. 2010 Volume 15 No 3 ... Understanding the factors that regulate body fat distribution should not only give insight ... glucocorticoids may sculpture body fat and change the pathogenicity of obesity.

  1. Induced resistance and gene expression in wheat against leaf rust ...

    African Journals Online (AJOL)

    uvp

    2013-05-15

    May 15, 2013 ... Key words: Wheat leaf rust, induced resistance, priming, gene expression, immunoblotting, crude Agapanthus africanus extract. ... agents, including several synthetic and natural plant activators (Garcia-Brugger et al., ... priming and direct defence activation (van Hulten et al.,. 2006). The identification of new ...

  2. Resistance Pattern and Detection of Metallo-beta-lactamase Genes ...

    African Journals Online (AJOL)

    2018-02-23

    6 days ago ... Resistance Pattern and Detection of Metallo-beta-lactamase Genes in Clinical Isolates of. Pseudomonas aeruginosa in a Central Nigeria Tertiary Hospital. Niger. J Clin Pract 2018 ... last resort when dealing with MDR Gram-negative bacteria, but there .... no change in the antibiotics susceptibility pattern of.

  3. Microbiological quality of ready-to-eat salads: an underestimated vehicle of bacteria and clinically relevant antibiotic resistance genes.

    Science.gov (United States)

    Campos, Joana; Mourão, Joana; Pestana, Nazaré; Peixe, Luísa; Novais, Carla; Antunes, Patrícia

    2013-09-16

    The increase demand for fresh vegetables is causing an expansion of the market for minimally processed vegetables along with new recognized food safety problems. To gain further insight on this topic we analyzed the microbiological quality of Portuguese ready-to-eat salads (RTS) and their role in the spread of bacteria carrying acquired antibiotic resistance genes, food products scarcely considered in surveillance studies. A total of 50 RTS (7 brands; split or mixed leaves, carrot, corn) were collected in 5 national supermarket chains in Porto region (2010). They were tested for aerobic mesophilic counts, coliforms and Escherichia coli counts as well as for the presence of Salmonella and Listeria monocytogenes. Samples were also plated in different selective media with/without antibiotics before and after enrichment. The E. coli, other coliforms and Enterococcus recovered were characterized for antibiotic resistance profiles and clonality with phenotypic and genetic approaches. A high number of RTS presented poor microbiological quality (86%--aerobic mesophilic counts, 74%--coliforms, 4%--E. coli), despite the absence of screened pathogens. In addition, a high diversity of bacteria (species and clones) and antibiotic resistance backgrounds (phenotypes and genotypes) were observed, mostly with enrichment and antibiotic selective media. E. coli was detected in 13 samples (n=78; all types and 4 brands; phylogenetic groups A, B1 and D; none STEC) with resistance to tetracycline [72%; tet(A) and/or tet(B)], streptomycin (58%; aadA and/or strA-strB), sulfamethoxazole (50%; sul1 and/or sul2), trimethoprim (50%; dfrA1 or dfrA12), ampicillin (49%; blaTEM), nalidixic acid (36%), ciprofloxacin (5%) or chloramphenicol (3%; catA). E. coli clones, including the widespread group D/ST69, were detected in different samples from the same brand or different brands pointing out to a potential cross-contamination. Other clinically relevant resistance genes were detected in 2 Raoultella

  4. Ornamental fish as a source of plasmid-mediated quinolone resistance genes and antibiotic resistance plasmids.

    Science.gov (United States)

    Dobiasova, Hana; Kutilova, Iva; Piackova, Veronika; Vesely, Tomas; Cizek, Alois; Dolejska, Monika

    2014-07-16

    Growing ornamental fish industry is associated with public health concerns including extensive antibiotic use accompanied by increasing antibiotic resistance. The aim of this study was to analyze Aeromonas isolates from imported tropical ornamental fish and coldwater koi carps bred in the Czech Republic to assess the potential risk of ornamental fish as a source of plasmid-mediated quinolone resistance genes (PMQR) and antibiotic resistance plasmids. A collection of Aeromonas spp. with reduced susceptibility to ciprofloxacin (MIC ≥ 0.05 mg/L) was selected for the detection of PMQR genes. Isolates harbouring PMQR genes were further analyzed for the additional antibiotic resistance, integron content, clonality, biofilm production and transferability of PMQR genes by conjugation and transformation. Comparative analysis of plasmids carrying PMQR genes was performed. Fifteen (19%, n=80) isolates from koi carps and 18 (24%, n=76) isolates from imported ornamental fish were positive for qnrS2, aac(6')-Ib-cr or qnrB17 genes. PMQR-positive isolates from imported ornamental fish showed higher MIC levels to quinolones, multiresistance and diverse content of antibiotic resistance genes and integrons compared to the isolates from the carps. Related IncU plasmids harbouring qnrS2 and aac(6')-Ib-cr genes were found in Aeromonas spp. from imported ornamental fish and koi carps from various geographical areas. Ornamental fish may represent a potential source of multiresistant bacteria and mobile genetic elements for the environment and for humans. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Resistance gene identification from Larimichthys crocea with machine learning techniques

    Science.gov (United States)

    Cai, Yinyin; Liao, Zhijun; Ju, Ying; Liu, Juan; Mao, Yong; Liu, Xiangrong

    2016-12-01

    The research on resistance genes (R-gene) plays a vital role in bioinformatics as it has the capability of coping with adverse changes in the external environment, which can form the corresponding resistance protein by transcription and translation. It is meaningful to identify and predict R-gene of Larimichthys crocea (L.Crocea). It is friendly for breeding and the marine environment as well. Large amounts of L.Crocea’s immune mechanisms have been explored by biological methods. However, much about them is still unclear. In order to break the limited understanding of the L.Crocea’s immune mechanisms and to detect new R-gene and R-gene-like genes, this paper came up with a more useful combination prediction method, which is to extract and classify the feature of available genomic data by machine learning. The effectiveness of feature extraction and classification methods to identify potential novel R-gene was evaluated, and different statistical analyzes were utilized to explore the reliability of prediction method, which can help us further understand the immune mechanisms of L.Crocea against pathogens. In this paper, a webserver called LCRG-Pred is available at http://server.malab.cn/rg_lc/.

  6. Relationship between Psidium species (Myrtaceae) by resistance gene analog markers: focus on nematode resistance.

    Science.gov (United States)

    Noia, L R; Tuler, A C; Ferreira, A; Ferreira, M F S

    2017-03-16

    Guava (Psidium guajava L.) crop is severely affected by the nematode Meloidogyne enterolobii. Native Psidium species have been reported as sources of resistance against this nematode. Knowledge on the molecular relationship between Psidium species based on plant resistance gene analogs (RGA) can be useful in the genetic breeding of guava for resistance to M. enterolobii. In this study, RGA markers from conserved domains, and structural features of plant R genes, were employed to characterize Psidium species and establish genetic proximity, with a focus on nematode resistance. SSR markers were also applied owing to their neutral nature, thus differing from RGA markers. For this, species reported as sources of resistance to M. enterolobii, such as P. cattleianum and P. friedrichsthalianum, as well as species occurring in the Atlantic Rainforest and susceptible genotypes, were investigated. In 10 evaluated Psidium species, high interspecific genetic variability was verified through RGA and SSR markers, with intraspecific variation in P. guajava higher with SSR, as was expected. Resistant species were clustered by RGA markers, and differential amplicons among genotypes resistant and susceptible to M. enterolobii were identified. Knowledge on the molecular relationships between Psidium species constitutes useful information for breeding of the guava tree, providing direction for hybridization and material for rootstocks. Additionally, the genetic relationship between native species, which have been little studied, and P. guajava were estimated by RGAs, which were confirmed as important markers for genetic diversity related to pathogen resistance.

  7. Metagenomic Analysis of Antibiotic Resistance Genes in Dairy Cow Feces following Therapeutic Administration of Third Generation Cephalosporin.

    Directory of Open Access Journals (Sweden)

    Lindsey Chambers

    Full Text Available Although dairy manure is widely applied to land, it is relatively understudied compared to other livestock as a potential source of antibiotic resistance genes (ARGs to the environment and ultimately to human pathogens. Ceftiofur, the most widely used antibiotic used in U.S. dairy cows, is a 3rd generation cephalosporin, a critically important class of antibiotics to human health. The objective of this study was to evaluate the effect of typical ceftiofur antibiotic treatment on the prevalence of ARGs in the fecal microbiome of dairy cows using a metagenomics approach. β-lactam ARGs were found to be elevated in feces from Holstein cows administered ceftiofur (n = 3 relative to control cows (n = 3. However, total numbers of ARGs across all classes were not measurably affected by ceftiofur treatment, likely because of dominance of unaffected tetracycline ARGs in the metagenomics libraries. Functional analysis via MG-RAST further revealed that ceftiofur treatment resulted in increases in gene sequences associated with "phages, prophages, transposable elements, and plasmids", suggesting that this treatment also enriched the ability to horizontally transfer ARGs. Additional functional shifts were noted with ceftiofur treatment (e.g., increase in genes associated with stress, chemotaxis, and resistance to toxic compounds; decrease in genes associated with metabolism of aromatic compounds and cell division and cell cycle, along with measureable taxonomic shifts (increase in Bacterioidia and decrease in Actinobacteria. This study demonstrates that ceftiofur has a broad, measureable and immediate effect on the cow fecal metagenome. Given the importance of 3rd generation cephalospirins to human medicine, their continued use in dairy cattle should be carefully considered and waste treatment strategies to slow ARG dissemination from dairy cattle manure should be explored.

  8. Metagenomic Analysis of Antibiotic Resistance Genes in Dairy Cow Feces following Therapeutic Administration of Third Generation Cephalosporin.

    Science.gov (United States)

    Chambers, Lindsey; Yang, Ying; Littier, Heather; Ray, Partha; Zhang, Tong; Pruden, Amy; Strickland, Michael; Knowlton, Katharine

    2015-01-01

    Although dairy manure is widely applied to land, it is relatively understudied compared to other livestock as a potential source of antibiotic resistance genes (ARGs) to the environment and ultimately to human pathogens. Ceftiofur, the most widely used antibiotic used in U.S. dairy cows, is a 3rd generation cephalosporin, a critically important class of antibiotics to human health. The objective of this study was to evaluate the effect of typical ceftiofur antibiotic treatment on the prevalence of ARGs in the fecal microbiome of dairy cows using a metagenomics approach. β-lactam ARGs were found to be elevated in feces from Holstein cows administered ceftiofur (n = 3) relative to control cows (n = 3). However, total numbers of ARGs across all classes were not measurably affected by ceftiofur treatment, likely because of dominance of unaffected tetracycline ARGs in the metagenomics libraries. Functional analysis via MG-RAST further revealed that ceftiofur treatment resulted in increases in gene sequences associated with "phages, prophages, transposable elements, and plasmids", suggesting that this treatment also enriched the ability to horizontally transfer ARGs. Additional functional shifts were noted with ceftiofur treatment (e.g., increase in genes associated with stress, chemotaxis, and resistance to toxic compounds; decrease in genes associated with metabolism of aromatic compounds and cell division and cell cycle), along with measureable taxonomic shifts (increase in Bacterioidia and decrease in Actinobacteria). This study demonstrates that ceftiofur has a broad, measureable and immediate effect on the cow fecal metagenome. Given the importance of 3rd generation cephalospirins to human medicine, their continued use in dairy cattle should be carefully considered and waste treatment strategies to slow ARG dissemination from dairy cattle manure should be explored.

  9. Putative resistance genes in the CitEST database

    Directory of Open Access Journals (Sweden)

    Simone Guidetti-Gonzalez

    2007-01-01

    Full Text Available Disease resistance in plants is usually associated with the activation of a wide variety of defense responses to prevent pathogen replication and/or movement. The ability of the host plant to recognize the pathogen and to activate defense responses is regulated by direct or indirect interaction between the products of plant resistance (R and pathogen avirulence (Avr genes. Attempted infection of plants by avirulent pathogens elicits a battery of defenses often followed by the collapse of the challenged host cells. Localized host cell death may help to prevent the pathogen from spreading to uninfected tissues, known as hypersensitive response (HR. When either the plant or the pathogen lacks its cognate gene, activation of the plant’s defense responses fails to occur or is delayed and does not prevent pathogen colonization. In the CitEST database, we identified 1,300 reads related to R genes in Citrus which have been reported in other plant species. These reads were translated in silico, and alignments of their amino acid sequences revealed the presence of characteristic domains and motifs that are specific to R gene classes. The description of the reads identified suggests that they function as resistance genes in citrus.

  10. Heavy metal and disinfectant resistance genes among livestock-associated methicillin-resistant Staphylococcus aureus isolates

    DEFF Research Database (Denmark)

    Argudin, Maria Angeles; Lauzat, Birgit; Kraushaar, Britta

    2016-01-01

    Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC)398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other...... substances with antimicrobial activity applied in animal feed, including metal-containing compounds might contribute to their selection. Some of these genes have been found in various novel SCCmec cassettes. The aim of this study was to assess the occurrence of metal-resistance genes among a LA-S. aureus...... collection [n = 554, including 542 MRSA and 12 methicillin-susceptible S. aureus (MSSA)] isolated from livestock and food thereof. Most LA-MRSA isolates (76%) carried at least one metal-resistance gene. Among the LA-MRSA CC398 isolates (n = 456), 4.8%, 0.2%, 24.3% and 71.5% were positive for arsA (arsenic...

  11. Bacteria from Animals as a Pool of Antimicrobial Resistance Genes

    Science.gov (United States)

    Argudín, Maria Angeles; Deplano, Ariane; Meghraoui, Alaeddine; Dodémont, Magali; Heinrichs, Amelie; Denis, Olivier; Nonhoff, Claire; Roisin, Sandrine

    2017-01-01

    Antimicrobial agents are used in both veterinary and human medicine. The intensive use of antimicrobials in animals may promote the fixation of antimicrobial resistance genes in bacteria, which may be zoonotic or capable to transfer these genes to human-adapted pathogens or to human gut microbiota via direct contact, food or the environment. This review summarizes the current knowledge of the use of antimicrobial agents in animal health and explores the role of bacteria from animals as a pool of antimicrobial resistance genes for human bacteria. This review focused in relevant examples within the ESC(K)APE (Enterococcus faecium, Staphylococcus aureus, Clostridium difficile (Klebsiella pneumoniae), Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae) group of bacterial pathogens that are the leading cause of nosocomial infections throughout the world. PMID:28587316

  12. Bacteria from Animals as a Pool of Antimicrobial Resistance Genes

    Directory of Open Access Journals (Sweden)

    Maria Angeles Argudín

    2017-06-01

    Full Text Available Antimicrobial agents are used in both veterinary and human medicine. The intensive use of antimicrobials in animals may promote the fixation of antimicrobial resistance genes in bacteria, which may be zoonotic or capable to transfer these genes to human-adapted pathogens or to human gut microbiota via direct contact, food or the environment. This review summarizes the current knowledge of the use of antimicrobial agents in animal health and explores the role of bacteria from animals as a pool of antimicrobial resistance genes for human bacteria. This review focused in relevant examples within the ESC(KAPE (Enterococcus faecium, Staphylococcus aureus, Clostridium difficile (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae group of bacterial pathogens that are the leading cause of nosocomial infections throughout the world.

  13. Abundance of antibiotics, antibiotic resistance genes and bacterial community composition in wastewater effluents from different Romanian hospitals.

    Science.gov (United States)

    Szekeres, Edina; Baricz, Andreea; Chiriac, Cecilia Maria; Farkas, Anca; Opris, Ocsana; Soran, Maria-Loredana; Andrei, Adrian-Stefan; Rudi, Knut; Balcázar, Jose Luis; Dragos, Nicolae; Coman, Cristian

    2017-06-01

    Antimicrobial resistance represents a growing and significant public health threat, which requires a global response to develop effective strategies and mitigate the emergence and spread of this phenomenon in clinical and environmental settings. We investigated, therefore, the occurrence and abundance of several antibiotics and antibiotic resistance genes (ARGs), as well as bacterial community composition in wastewater effluents from different hospitals located in the Cluj County, Romania. Antibiotic concentrations ranged between 3.67 and 53.05 μg L -1 , and the most abundant antibiotic classes were β-lactams, glycopeptides, and trimethoprim. Among the ARGs detected, 14 genes confer resistance to β-lactams, aminoglycosides, chloramphenicol, macrolide-lincosamide-streptogramin B (MLSB) antibiotics, sulfonamides, and tetracyclines. Genes encoding quaternary ammonium resistance and a transposon-related element were also detected. The sulI and qacEΔ1 genes, which confer resistance to sulfonamides and quaternary ammonium, had the highest relative abundance with values ranging from 5.33 × 10 -2 to 1.94 × 10 -1 and 1.94 × 10 -2 to 4.89 × 10 -2 copies/16 rRNA gene copies, respectively. The dominant phyla detected in the hospital wastewater samples were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Among selected hospitals, one of them applied an activated sludge and chlorine disinfection process before releasing the effluent to the municipal collector. This conventional wastewater treatment showed moderate removal efficiency of the studied pollutants, with a 55-81% decrease in antibiotic concentrations, 1-3 order of magnitude lower relative abundance of ARGs, but with a slight increase of some potentially pathogenic bacteria. Given this, hospital wastewaters (raw or treated) may contribute to the spread of these emerging pollutants in the receiving environments. To the best of our knowledge, this study quantified for the first time the

  14. Occurrence and removal of antibiotics and the corresponding resistance genes in wastewater treatment plants: effluents' influence to downstream water environment.

    Science.gov (United States)

    Li, Jianan; Cheng, Weixiao; Xu, Like; Jiao, Yanan; Baig, Shams Ali; Chen, Hong

    2016-04-01

    In this study, the occurrence of 8 antibiotics [3 tetracyclines (TCs), 4 sulfonamides, and 1 trimethoprim (TMP)], 12 antibiotic resistance genes (ARGs) (10 tet, 2 sul), 4 types of bacteria [no antibiotics, anti-TC, anti-sulfamethoxazole (SMX), and anti-double], and intI1 in two wastewater treatment plants (WWTPs) were assessed and their influences in downstream lake were investigated. Both WWTPs' effluent demonstrated some similarities, but the abundance and removal rate varied significantly. Results revealed that biological treatment mainly removed antibiotics and ARGs, whereas physical techniques were found to eliminate antibiotic resistance bacteria (ARBs) abundance (about 1 log for each one). UV disinfection did not significantly enhance the removal efficiency, and the release of the abundantly available target contaminants from the excess sludge may pose threats to human and the environment. Different antibiotics showed diverse influences on the downstream lake, and the concentrations of sulfamethazine (SM2) and SMX were observed to increase enormously. The total ARG abundance ascended about 0.1 log and some ARGs (e.g., tetC, intI1, tetA) increased due to the high input of the effluent. In addition, the abundance of ARB variation in the lake also changed, but the abundance of four types of bacteria remained stable in the downstream sampling sites.

  15. Characterisation of streptomycin resistance determinants in Danish isolates of Salmonella typhimurium

    DEFF Research Database (Denmark)

    Madsen, Lissi; Aarestrup, Frank Møller; Olsen, John Elmerdahl

    2000-01-01

    Fifty six Danish streptomycin (Sm) resistant isolates of Salmonella enterica serotype Typhimurium from pigs (n=34), calves (n=3) and humans (n=19) were characterised with respect to co-resistances (14 drugs), transferability of Sm-resistance by conjugation, genetic determinants encoding Sm-resistance...... and diversity with respect to localisation of genes in the genome and DNA-sequences. Forty-six strains carried resistance(s) other than Sm-resistance. Nineteen different coresistance patterns were observed and tetracycline was the most commonly observed resistance in these patterns. In 22 of the strains, Sm-resistance...

  16. Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding.

    Science.gov (United States)

    Moura, Tiane Martin de; Campos, Fabrício Souza; d'Azevedo, Pedro Alves; Van Der Sand, Sueli Teresinha; Franco, Ana Cláudia; Frazzon, Jeverson; Frazzon, Ana Paula Guedes

    2012-10-01

    Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS) and coagulasepositive (CoPS) isolates from black pudding in southern Brazil. Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa) and enterotoxin (se) genes was investigated by polymerase chain reaction. The isolates were divided into 2 groups: 75.6% (62/82) were CoNS and 24.4% (20/82) were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8%) and Staphylococcus carnosus (15.9%) were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82) of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6%) and seb (27.5%). The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

  17. Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding

    Directory of Open Access Journals (Sweden)

    Tiane Martin de Moura

    2012-10-01

    Full Text Available INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS and coagulasepositive (CoPS isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa and enterotoxin (se genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82 were CoNS and 24.4% (20/82 were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8% and Staphylococcus carnosus (15.9% were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82 of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6% and seb (27.5%. CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

  18. Functional study of the novel multidrug resistance gene HA117 and its comparison to multidrug resistance gene 1

    Directory of Open Access Journals (Sweden)

    Chen Tingfu

    2010-07-01

    Full Text Available Abstract Background The novel gene HA117 is a multidrug resistance (MDR gene expressed by all-trans retinoic acid-resistant HL-60 cells. In the present study, we compared the multidrug resistance of the HA117 with that of the classical multidrug resistance gene 1 (MDR1 in breast cancer cell line 4T1. Methods Transduction of the breast cancer cell line 4T1 with adenoviral vectors encoding the HA117 gene and the green fluorescence protein gene (GFP (Ad-GFP-HA117, the MDR1 and GFP (Ad-GFP-MDR1 or GFP (Ad-GFP was respectively carried out. The transduction efficiency and the multiplicity of infection (MOI were detected by fluorescence microscope and flow cytometry. The transcription of HA117 gene and MDR1 gene were detected by reverse transcription polymerase chain reaction (RT-PCR. Western blotting analysis was used to detect the expression of P-glycoprotein (P-gp but the expression of HA117 could not be analyzed as it is a novel gene and its antibody has not yet been synthesized. The drug-excretion activity of HA117 and MDR1 were determined by daunorubicin (DNR efflux assay. The drug sensitivities of 4T1/HA117 and 4T1/MDR1 to chemotherapeutic agents were detected by Methyl-Thiazolyl-Tetrazolium (MTT assay. Results The transducted efficiency of Ad-GFP-HA117 and Ad-GFP-MDR1 were 75%-80% when MOI was equal to 50. The transduction of Ad-GFP-HA117 and Ad-GFP-MDR1 could increase the expression of HA117 and MDR1. The drug resistance index to Adriamycin (ADM, vincristine (VCR, paclitaxel (Taxol and bleomycin (BLM increased to19.8050, 9.0663, 9.7245, 3.5650 respectively for 4T1/HA117 and 24.2236, 11.0480, 11.3741, 0.9630 respectively for 4T1/MDR1 as compared to the control cells. There were no significant differences in drug sensitivity between 4T1/HA117 and 4T1/MDR1 for the P-gp substrates (ADM, VCR and Taxol (P Conclusions These results confirm that HA117 is a strong MDR gene in both HL-60 and 4T1 cells. Furthermore, our results indicate that the MDR

  19. Heavy metal and disinfectant resistance genes among livestock-associated methicillin-resistant Staphylococcus aureus isolates.

    Science.gov (United States)

    Argudín, M Angeles; Lauzat, Birgit; Kraushaar, Britta; Alba, Patricia; Agerso, Yvonne; Cavaco, Lina; Butaye, Patrick; Porrero, M Concepción; Battisti, Antonio; Tenhagen, Bernd-Alois; Fetsch, Alexandra; Guerra, Beatriz

    2016-08-15

    Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC) 398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other substances with antimicrobial activity applied in animal feed, including metal-containing compounds might contribute to their selection. Some of these genes have been found in various novel SCCmec cassettes. The aim of this study was to assess the occurrence of metal-resistance genes among a LA-S. aureus collection [n=554, including 542 MRSA and 12 methicillin-susceptible S. aureus (MSSA)] isolated from livestock and food thereof. Most LA-MRSA isolates (76%) carried at least one metal-resistance gene. Among the LA-MRSA CC398 isolates (n=456), 4.8%, 0.2%, 24.3% and 71.5% were positive for arsA (arsenic compounds), cadD (cadmium), copB (copper) and czrC (zinc/cadmium) resistance genes, respectively. In contrast, among the LA-MRSA non-CC398 isolates (n=86), 1.2%, 18.6% and 16.3% were positive for the cadD, copB and czrC genes, respectively, and none were positive for arsA. Of the LA-MRSA CC398 isolates, 72% carried one metal-resistance gene, and the remaining harboured two or more in different combinations. Differences between LA-MRSA CC398 and non-CC398 were statistically significant for arsA and czrC. The czrC gene was almost exclusively found (98%) in the presence of SCCmec V in both CC398 and non-CC398 LA-MRSA isolates from different sources. Regarding the LA-MSSA isolates (n=12), some (n=4) were also positive for metal-resistance genes. This study shows that genes potentially conferring metal-resistance are frequently present in LA-MRSA. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Genomes, diversity and resistance gene analogues in Musa species.

    Science.gov (United States)

    Azhar, M; Heslop-Harrison, J S

    2008-01-01

    Resistance genes (R genes) in plants are abundant and may represent more than 1% of all the genes. Their diversity is critical to the recognition and response to attack from diverse pathogens. Like many other crops, banana and plantain face attacks from potentially devastating fungal and bacterial diseases, increased by a combination of worldwide spread of pathogens, exploitation of a small number of varieties, new pathogen mutations, and the lack of effective, benign and cheap chemical control. The challenge for plant breeders is to identify and exploit genetic resistances to diseases, which is particularly difficult in banana and plantain where the valuable cultivars are sterile, parthenocarpic and mostly triploid so conventional genetic analysis and breeding is impossible. In this paper, we review the nature of R genes and the key motifs, particularly in the Nucleotide Binding Sites (NBS), Leucine Rich Repeat (LRR) gene class. We present data about identity, nature and evolutionary diversity of the NBS domains of Musa R genes in diploid wild species with the Musa acuminata (A), M. balbisiana (B), M. schizocarpa (S), M. textilis (T), M. velutina and M. ornata genomes, and from various cultivated hybrid and triploid accessions, using PCR primers to isolate the domains from genomic DNA. Of 135 new sequences, 75% of the sequenced clones had uninterrupted open reading frames (ORFs), and phylogenetic UPGMA tree construction showed four clusters, one from Musa ornata, one largely from the B and T genomes, one from A and M. velutina, and the largest with A, B, T and S genomes. Only genes of the coiled-coil (non-TIR) class were found, typical of the grasses and presumably monocotyledons. The analysis of R genes in cultivated banana and plantain, and their wild relatives, has implications for identification and selection of resistance genes within the genus which may be useful for plant selection and breeding and also for defining relationships and genome evolution

  1. Gene pyramiding enhances durable blast disease resistance in rice.

    Science.gov (United States)

    Fukuoka, Shuichi; Saka, Norikuni; Mizukami, Yuko; Koga, Hironori; Yamanouchi, Utako; Yoshioka, Yosuke; Hayashi, Nagao; Ebana, Kaworu; Mizobuchi, Ritsuko; Yano, Masahiro

    2015-01-14

    Effective control of blast, a devastating fungal disease of rice, would increase and stabilize worldwide food production. Resistance mediated by quantitative trait loci (QTLs), which usually have smaller individual effects than R-genes but confer broad-spectrum or non-race-specific resistance, is a promising alternative to less durable race-specific resistance for crop improvement, yet evidence that validates the impact of QTL combinations (pyramids) on the durability of plant disease resistance has been lacking. Here, we developed near-isogenic experimental lines representing all possible combinations of four QTL alleles from a durably resistant cultivar. These lines enabled us to evaluate the QTLs singly and in combination in a homogeneous genetic background. We present evidence that pyramiding QTL alleles, each controlling a different response to M. oryzae, confers strong, non-race-specific, environmentally stable resistance to blast disease. Our results suggest that this robust defence system provides durable resistance, thus avoiding an evolutionary "arms race" between a crop and its pathogen.

  2. Corneal staining after treatment with topical tetracycline

    NARCIS (Netherlands)

    Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Slomovic, Allan R.; Spanjaard, Lodewijk

    2006-01-01

    PURPOSE: The purpose of this paper is to report a case of corneal staining after treatment with topical tetracycline. METHODS: A patient with crystalline keratopathy caused by Streptococcus viridans after corneal transplantation was treated topically with tetracycline eye drops, based on results of

  3. Ion Suppression Study for Tetracyclines in Feed

    NARCIS (Netherlands)

    Chico, J.; Holthoon, van F.L.; Zuidema, T.

    2012-01-01

    Ion suppression in analysis of tetracyclines in feed was studied. The conventional analysis consists of a liquid extraction followed by a clean-up step using solid phase extraction (SPE) technique and analysis of the tetracyclines by liquid chromatography and mass spectrometric detection. Various

  4. Reaction of tetracycline with biologically relevant chloramines.

    Science.gov (United States)

    Benavides, J; Barrias, P; Piro, N; Arenas, A; Orrego, A; Pino, E; Villegas, L; Dorta, E; Aspée, A; López-Alarcón, C

    2017-05-05

    Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent production of hypochlorous acid (HOCl), monochloramine (NH2Cl), and protein-derived chloramines. As the therapy for eradicating H. pylori is partially based on the use of tetracycline, we studied the kinetic of its consumption elicited by HOCl, NH2Cl, N-chloro-n-butylamine (NHCl-But, used as a lysine-derived chloramine model), and lysozyme-derived chloramines. In the micromolar concentration range, tetracycline reacted rapidly with HOCl, generating in the first few seconds intermediates of short half-life. In contrast, a slow tetracycline consumption was observed in the presence of high NH2Cl and NHCl-But concentrations (millimolar range). Similar chlorinated products of tetracycline were identified by mass spectrometry, in the presence of HOCl and NH2Cl. These results evidenced that tautomers of tetracycline are pivotal intermediates in all reactions. In spite of the low reactivity of chloramines towards tetracycline, it is evident that, in the concentration range where they are produced in a H. pylori infection (millimolar range), the reactions lead to oxidation and/or chlorination of tetracycline. This kind of reactions, which were also observed triggered by lysozyme-derived chloramines, could limit the efficiency of the tetracycline-based therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Reaction of tetracycline with biologically relevant chloramines

    Science.gov (United States)

    Benavides, J.; Barrias, P.; Piro, N.; Arenas, A.; Orrego, A.; Pino, E.; Villegas, L.; Dorta, E.; Aspée, A.; López-Alarcón, C.

    2017-05-01

    Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent production of hypochlorous acid (HOCl), monochloramine (NH2Cl), and protein-derived chloramines. As the therapy for eradicating H. pylori is partially based on the use of tetracycline, we studied the kinetic of its consumption elicited by HOCl, NH2Cl, N-chloro-n-butylamine (NHCl-But, used as a lysine-derived chloramine model), and lysozyme-derived chloramines. In the micromolar concentration range, tetracycline reacted rapidly with HOCl, generating in the first few seconds intermediates of short half-life. In contrast, a slow tetracycline consumption was observed in the presence of high NH2Cl and NHCl-But concentrations (millimolar range). Similar chlorinated products of tetracycline were identified by mass spectrometry, in the presence of HOCl and NH2Cl. These results evidenced that tautomers of tetracycline are pivotal intermediates in all reactions. In spite of the low reactivity of chloramines towards tetracycline, it is evident that, in the concentration range where they are produced in a H. pylori infection (millimolar range), the reactions lead to oxidation and/or chlorination of tetracycline. This kind of reactions, which were also observed triggered by lysozyme-derived chloramines, could limit the efficiency of the tetracycline-based therapy.

  6. Recombination Rate Heterogeneity within Arabidopsis Disease Resistance Genes.

    Directory of Open Access Journals (Sweden)

    Kyuha Choi

    2016-07-01

    Full Text Available Meiotic crossover frequency varies extensively along chromosomes and is typically concentrated in hotspots. As recombination increases genetic diversity, hotspots are predicted to occur at immunity genes, where variation may be beneficial. A major component of plant immunity is recognition of pathogen Avirulence (Avr effectors by resistance (R genes that encode NBS-LRR domain proteins. Therefore, we sought to test whether NBS-LRR genes would overlap with meiotic crossover hotspots using experimental genetics in Arabidopsis thaliana. NBS-LRR genes tend to physically cluster in plant genomes; for example, in Arabidopsis most are located in large clusters on the south arms of chromosomes 1 and 5. We experimentally mapped 1,439 crossovers within these clusters and observed NBS-LRR gene associated hotspots, which were also detected as historical hotspots via analysis of linkage disequilibrium. However, we also observed NBS-LRR gene coldspots, which in some cases correlate with structural heterozygosity. To study recombination at the fine-scale we used high-throughput sequencing to analyze ~1,000 crossovers within the RESISTANCE TO ALBUGO CANDIDA1 (RAC1 R gene hotspot. This revealed elevated intragenic crossovers, overlapping nucleosome-occupied exons that encode the TIR, NBS and LRR domains. The highest RAC1 recombination frequency was promoter-proximal and overlapped CTT-repeat DNA sequence motifs, which have previously been associated with plant crossover hotspots. Additionally, we show a significant influence of natural genetic variation on NBS-LRR cluster recombination rates, using crosses between Arabidopsis ecotypes. In conclusion, we show that a subset of NBS-LRR genes are strong hotspots, whereas others are coldspots. This reveals a complex recombination landscape in Arabidopsis NBS-LRR genes, which we propose results from varying coevolutionary pressures exerted by host-pathogen relationships, and is influenced by structural heterozygosity.

  7. Continental-scale pollution of estuaries with antibiotic resistance genes.

    Science.gov (United States)

    Zhu, Yong-Guan; Zhao, Yi; Li, Bing; Huang, Chu-Long; Zhang, Si-Yu; Yu, Shen; Chen, Yong-Shan; Zhang, Tong; Gillings, Michael R; Su, Jian-Qiang

    2017-01-30

    Antibiotic resistance genes (ARGs) have moved from the environmental resistome into human commensals and pathogens, driven by human selection with antimicrobial agents. These genes have increased in abundance in humans and domestic animals, to become common components of waste streams. Estuarine habitats lie between terrestrial/freshwater and marine ecosystems, acting as natural filtering points for pollutants. Here, we have profiled ARGs in sediments from 18 estuaries over 4,000 km of coastal China using high-throughput quantitative polymerase chain reaction, and investigated their relationship with bacterial communities, antibiotic residues and socio-economic factors. ARGs in estuarine sediments were diverse and abundant, with over 200 different resistance genes being detected, 18 of which were found in all 90 sediment samples. The strong correlations of identified resistance genes with known mobile elements, network analyses and partial redundancy analysis all led to the conclusion that human activity is responsible for the abundance and dissemination of these ARGs. Such widespread pollution with xenogenetic elements has environmental, agricultural and medical consequences.

  8. Mapping fusiform rust resistance genes within a complex mating design of loblolly pine

    Science.gov (United States)

    Tania Quesada; Marcio F.R. Resende Jr.; Patricio Munoz; Jill L. Wegrzyn; David B. Neale; Matias Kirst; Gary F. Peter; Salvador A. Gezan; C.Dana Nelson; John M. Davis

    2014-01-01

    Fusiform rust resistance can involve gene-for-gene interactions where resistance (Fr) genes in the host interact with corresponding avirulence genes in the pathogen, Cronartium quercuum f.sp. fusiforme (Cqf). Here, we identify trees with Fr genes in a loblolly pine population derived from a complex mating design challenged with two Cqf inocula (one gall and 10 gall...

  9. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    KAUST Repository

    Hong, Pei-Ying

    2013-07-31

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  10. Evaluation of canine-specific minocycline and doxycycline susceptibility breakpoints for meticillin-resistant Staphylococcus pseudintermedius isolates from dogs.

    Science.gov (United States)

    Hnot, Melanie L; Cole, Lynette K; Lorch, Gwendolen; Papich, Mark G; Rajala-Schultz, Paivi J; Daniels, Joshua B

    2015-10-01

    Using the US Clinical and Laboratory Standards Institute (CLSI) human tetracycline breakpoints to predict minocycline and doxycycline susceptibility of Staphylococcus pseudintermedius (SP) isolates from dogs is not appropriate because they are too high to meet pharmacokinetic/pharmacodynamic data using a standard dose. New breakpoints have been approved for doxycycline and proposed for minocycline. Revised breakpoints are four dilutions lower than tetracycline breakpoints, providing a more conservative standard for classification of isolates. The objectives of this study were to measure minimum inhibitory concentrations (MICs) of minocycline and doxycycline of 100 canine meticillin-resistant SP clinical isolates, compare their susceptibilities to minocycline and doxycycline based on current and revised standards, and document their tetracycline resistance genes. E-test strips were used to determine MICs. PCR was used to identify tet genes. Using the human tetracycline breakpoint of MIC ≤ 4 μg/mL, 76 isolates were susceptible to minocycline and 36 isolates were susceptible to doxycycline. In contrast, using the proposed minocycline breakpoint (MIC ≤ 0.25 μg/mL) and approved doxycycline breakpoint (MIC ≤ 0.125 μg/mL), 31 isolates were susceptible to both minocycline and doxycycline. Thirty-one isolates carried no tet genes, two had tet(K) and 67 had tet(M). Use of the human tetracycline breakpoints misclassified 45 and five of the isolates as susceptible to minocycline and doxycycline, respectively. PCR analysis revealed that 43 and five of the isolates classified as susceptible to minocycline and doxycycline, respectively, possessed the tetracycline resistance gene, tet(M), known to confer resistance to both drugs. These results underscore the importance of utilizing the proposed minocycline and approved doxycycline canine breakpoints in place of human tetracycline breakpoints. © 2015 ESVD and ACVD.

  11. Occurrence of antibiotics and antibiotic resistance genes in hospital and urban wastewaters and their impact on the receiving river.

    Science.gov (United States)

    Rodriguez-Mozaz, Sara; Chamorro, Sara; Marti, Elisabet; Huerta, Belinda; Gros, Meritxell; Sànchez-Melsió, Alexandre; Borrego, Carles M; Barceló, Damià; Balcázar, Jose Luis

    2015-02-01

    Antibiotic resistance has become a major health concern; thus, there is a growing interest in exploring the occurrence of antibiotic resistance genes (ARGs) in the environment as well as the factors that contribute to their emergence. Aquatic ecosystems provide an ideal setting for the acquisition and spread of ARGs due to the continuous pollution by antimicrobial compounds derived from anthropogenic activities. We investigated, therefore, the pollution level of a broad range of antibiotics and ARGs released from hospital and urban wastewaters, their removal through a wastewater treatment plant (WWTP) and their presence in the receiving river. Several antimicrobial compounds were detected in all water samples collected. Among antibiotic families, fluoroquinolones were detected at the highest concentration, especially in hospital effluent samples. Although good removal efficiency by treatment processes was observed for several antimicrobial compounds, most antibiotics were still present in WWTP effluents. The results also revealed that copy numbers of ARGs, such as blaTEM (resistance to β-lactams), qnrS (reduced susceptibility to fluoroquinolones), ermB (resistance to macrolides), sulI (resistance to sulfonamides) and tetW (resistance to tetracyclines), were detected at the highest concentrations in hospital effluent and WWTP influent samples. Although there was a significant reduction in copy numbers of these ARGs in WWTP effluent samples, this reduction was not uniform across analyzed ARGs. Relative concentration of ermB and tetW genes decreased as a result of wastewater treatment, whereas increased in the case of blaTEM, sulI and qnrS genes. The incomplete removal of antibiotics and ARGs in WWTP severely affected the receiving river, where both types of emerging pollutants were found at higher concentration in downstream waters than in samples collected upstream from the discharge point. Taken together, our findings demonstrate a widespread occurrence of

  12. A novel resistance gene, lnu(H), confers resistance to lincosamides inriemerella anatipestiferCH-2.

    Science.gov (United States)

    Luo, Hong-Yan; Liu, Ma-Feng; Wang, Ming-Shu; Zhao, Xin-Xin; Jia, Ren-Yong; Chen, Shun; Sun, Kun-Feng; Yang, Qiao; Wu, Ying; Chen, Xiao-Yue; Biville, Francis; Zou, Yuan-Feng; Jing, Bo; Cheng, An-Chun; Zhu, De-Kang

    2017-08-23

    The Gram-negative bacteria Riemerella anatipestifer CH-2 is resistant to lincosamide (the MIC value of lincomycin is 128 µg/ml). The G148_1775 gene of R. anatipestifer CH-2, designated lnu(H), encodes a 260-amino-acid protein with ≤ 41% identity to other reported lincosamide nucleotidyltransferases. The E. coli Rosetta (DE3) containing pBAD24-lnu(H) plasmid showed 4- and 2-fold increases in lincomycin and clindamycin MICs, respectively. A kinetic assay of the purified Lnu(H) enzyme for lincomycin and clindamycin showed that the protein could inactive lincosamides. Mass spectrometry analysis results demonstrated that the Lnu(H) enzyme catalyzed adenylation of lincosamides. In addition, the lnu(H) gene deletion strain exhibited 512- and 32-fold decreases in lincomycin and clindamycin MICs, respectively. Wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu(H) gene. The transformant ATCC 11845 (lnu(H)) acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, of the R. anatipestifer field isolates, 32% (56/175) were positive for the lnu(H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidyltransferase, which inactivates lincomycin and clindamycin by nucleotidylation, thus conferring high-level of lincosamide resistance to R. anatipestifer CH-2. Copyright © 2017. Published by Elsevier B.V.

  13. Whole-Genome Sequence Analysis of Antimicrobial Resistance Genes in Streptococcus uberis and Streptococcus dysgalactiae Isolates from Canadian Dairy Herds

    Directory of Open Access Journals (Sweden)

    Julián Reyes Vélez

    2017-05-01

    Full Text Available The objectives of this study are to determine the occurrence of antimicrobial resistance (AMR genes using whole-genome sequence (WGS of Streptococcus uberis (S. uberis and Streptococcus dysgalactiae (S. dysgalactiae isolates, recovered from dairy cows in the Canadian Maritime Provinces. A secondary objective included the exploration of the association between phenotypic AMR and the genomic characteristics (genome size, guanine–cytosine content, and occurrence of unique gene sequences. Initially, 91 isolates were sequenced, and of these isolates, 89 were assembled. Furthermore, 16 isolates were excluded due to larger than expected genomic sizes (>2.3 bp × 1,000 bp. In the final analysis, 73 were used with complete WGS and minimum inhibitory concentration records, which were part of the previous phenotypic AMR study, representing 18 dairy herds from the Maritime region of Canada (1. A total of 23 unique AMR gene sequences were found in the bacterial genomes, with a mean number of 8.1 (minimum: 5; maximum: 13 per genome. Overall, there were 10 AMR genes [ANT(6, TEM-127, TEM-163, TEM-89, TEM-95, Linb, Lnub, Ermb, Ermc, and TetS] present only in S. uberis genomes and 2 genes unique (EF-TU and TEM-71 to the S. dysgalactiae genomes; 11 AMR genes [APH(3′, TEM-1, TEM-136, TEM-157, TEM-47, TetM, bl2b, gyrA, parE, phoP, and rpoB] were found in both bacterial species. Two-way tabulations showed association between the phenotypic susceptibility to lincosamides and the presence of linB (P = 0.002 and lnuB (P < 0.001 genes and the between the presence of tetM (P = 0.015 and tetS (P = 0.064 genes and phenotypic resistance to tetracyclines only for the S. uberis isolates. The logistic model showed that the odds of resistance (to any of the phenotypically tested antimicrobials was 4.35 times higher when there were >11 AMR genes present in the genome, compared with <7 AMR genes (P < 0.001. The odds of resistance was lower for S

  14. Abundant rifampin resistance genes and significant correlations of antibiotic resistance genes and plasmids in various environments revealed by metagenomic analysis.

    Science.gov (United States)

    Ma, Liping; Li, Bing; Zhang, Tong

    2014-06-01

    In the present study, a newly developed metagenomic analysis approach was applied to investigate the abundance and diversity of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in aquaculture farm sediments, activated sludge, biofilm, anaerobic digestion sludge, and river water. BLASTX analysis against the Comprehensive Antibiotic Resistance Database was conducted for the metagenomic sequence data of each sample and then the ARG-like sequences were sorted based on structured sub-database using customized scripts. The results showed that freshwater fishpond sediment had the highest abundance (196 ppm), and anaerobic digestion sludge possessed the highest diversity (133 subtypes) of ARGs among the samples in this study. Significantly, rifampin resistance genes were universal in all the diverse samples and consistently accounted for 26.9~38.6 % of the total annotated ARG sequences. Furthermore, a significant linear correlation (R (2) = 0.924) was found between diversities (number of subtypes) of ARGs and diversities of plasmids in diverse samples. This work provided a wide spectrum scan of ARGs and MGEs in different environments and revealed the prevalence of rifampin resistance genes and the strong correlation between ARG diversity and plasmid diversity for the first time.

  15. Multiple antibiotic resistance genes distribution in ten large-scale membrane bioreactors for municipal wastewater treatment.

    Science.gov (United States)

    Sun, Yanmei; Shen, Yue-Xiao; Liang, Peng; Zhou, Jizhong; Yang, Yunfeng; Huang, Xia

    2016-12-01

    Wastewater treatment plants are thought to be potential reservoirs of antibiotic resistance genes. In this study, GeoChip was used for analyzing multiple antibiotic resistance genes, including four multidrug efflux system gene groups and three β-lactamase genes in ten large-scale membrane bioreactors (MBRs) for municipal wastewater treatment. Results revealed that the diversity of antibiotic genes varied a lot among MBRs, but about 40% common antibiotic resistance genes were existent. The average signal intensity of each antibiotic resistance group was similar among MBRs, nevertheless the total abundance of each group varied remarkably and the dominant resistance gene groups were different in individual MBR. The antibiotic resistance genes majorly derived from Proteobacteria and Actinobacteria. Further study indicated that TN, TP and COD of influent, temperature and conductivity of mixed liquor were significant (P<0.05) correlated to the multiple antibiotic resistance genes distribution in MBRs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Dissemination of antibiotic resistance genes from antibiotic producers to pathogens

    DEFF Research Database (Denmark)

    Jiang, Xinglin; Ellabaan, Mostafa M Hashim; Charusanti, Pep

    2017-01-01

    , that appear to be closely related to actinobacterial ARGs known to confer resistance against clinically important antibiotics. Furthermore, we identify two potential examples of recent horizontal transfer of actinobacterial ARGs to proteobacterial pathogens. Based on this bioinformatic evidence, we propose......It has been hypothesized that some antibiotic resistance genes (ARGs) found in pathogenic bacteria derive from antibiotic-producing actinobacteria. Here we provide bioinformatic and experimental evidence supporting this hypothesis. We identify genes in proteobacteria, including some pathogens...... and experimentally test a 'carry-back' mechanism for the transfer, involving conjugative transfer of a carrier sequence from proteobacteria to actinobacteria, recombination of the carrier sequence with the actinobacterial ARG, followed by natural transformation of proteobacteria with the carrier-sandwiched ARG. Our...

  17. [Horizontal transfer of antibiotic resistance genes in the environment].

    Science.gov (United States)

    Yang, Feng-Xia; Mao, Da-Qing; Luo, Yi; Wang, Qing; Mu, Quan-Hua

    2013-10-01

    The transfer of antibiotic resistance genes (ARGs), a new type of environmental pollutants, could have more adverse effects on the environment than the ARGs themselves, while the horizontal gene transfer (HGT) could be the most important propagation pathways of the ARGs, being one of the reasons for the growing pollution of ARGs in the environment. This paper systematically elaborated the molecular elements of the horizontal transfer of ARGs and the related affecting factors, which was of significance for investigating the molecular mechanisms of the horizontal transfer of the ARGs. In combining with the phylogenetic mechanisms of multiple antibiotic resistances, this paper also provided effective strategies to reduce the transfer and proliferation of ARGs in the environment. Based on the present contamination situations, the further researches on the horizontal transfer of ARGs in the environment were prospected.

  18. Dihydropteroate synthase gene mutations in Pneumocystis and sulfa resistance

    DEFF Research Database (Denmark)

    Huang, Laurence; Crothers, Kristina; Atzori, Chiara

    2004-01-01

    Pneumocystis pneumonia (PCP) remains a major cause of illness and death in HIV-infected persons. Sulfa drugs, trimethoprim-sulfamethoxazole (TMP-SMX) and dapsone are mainstays of PCP treatment and prophylaxis. While prophylaxis has reduced the incidence of PCP, its use has raised concerns about...... in the dihydropteroate synthase (DHPS) gene. Similar mutations have been observed in P. jirovecii. Studies have consistently demonstrated a significant association between the use of sulfa drugs for PCP prophylaxis and DHPS gene mutations. Whether these mutations confer resistance to TMP-SMX or dapsone plus trimethoprim...... for PCP treatment remains unclear. We review studies of DHPS mutations in P. jirovecii and summarize the evidence for resistance to sulfamethoxazole and dapsone....

  19. Horizontal gene transfer in the human gastrointestinal tract: potential spread of antibiotic resistance genes

    OpenAIRE

    Huddleston JR

    2014-01-01

    Jennifer R HuddlestonBiology Department, Abilene Christian University, Abilene, TX, USAAbstract: Bacterial infections are becoming increasingly difficult to treat due to widespread antibiotic resistance among pathogens. This review aims to give an overview of the major horizontal transfer mechanisms and their evolution and then demonstrate the human lower gastrointestinal tract as an environment in which horizontal gene transfer of resistance determinants occurs. Finally, implications for ant...

  20. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

    Directory of Open Access Journals (Sweden)

    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  1. Crg, a gene required for Ur-3-mediated rust resistance in common bean, maps to a resistance gene analog cluster.

    Science.gov (United States)

    Kalavacharia, V; Stavely, J R; Myers, J R; McClean, P E

    2000-11-01

    Race-specific resistance to the bean rust pathogen (Uromyces appendiculatus) is provided by a number of loci in common bean (Phaseolus vulgaris). The Ur-3 locus controls hypersensitive resistance (HR) to 44 of the 89 races curated in the United States. To better understand resistance mediated by this locus, we developed new genetic material for analysis. We developed a population of mutagenized seed of cv. Sierra (genotype = Ur-3 ur-4 ur-6) that was screened with a bean rust race that is normally incompatible (HR response) on Ur-3 genotypes. We discovered two mutants of common bean, crg and ur3-delta3, in which uredinia formed on leaves (a compatible interaction) following infection. The F1 generation from a cross of these two mutants expressed the HR response, and the F2 generation segregated in a ratio of 9:7 (HR/uredinia formation). Therefore, the two genes are unlinked. Further genetic analysis determined that the mutation in ur3-delta3 was in the Ur-3 locus, and the mutation in crg was in a newly discovered gene given the symbol Crg (Complements resistance gene). Each mutation was inherited in a recessive manner. Unlike ur3-delta3, crg expressed reduced compatibility to bean rust races 49 and 47 that are normally fully compatible on genotypes, such as Sierra, that are homozygous recessive at the Ur-4 and Ur-6 loci. This suggests a gene mutated in crg is normally a positive compatibility factor for the bean-bean rust interaction. Polymerase chain reaction analysis of crg with primers to common bean resistance gene analogs (RGA) that contain a nucleotide-binding site sequence similar to those found in a number of plant disease resistance genes revealed that crg is missing the SB1 RGA, but not the linked SB3 and SB5 RGAs. Genetic analyses revealed that Crg cosegregates with the SB1 RGA. These results demonstrate that Crg is located near a RGA cluster in the common bean genome.

  2. High level antibiotic resistance and relatedness of Staphylococcus ...

    African Journals Online (AJOL)

    Antibiotic resistant pattern show significant 100% resistance of S. aureus strains to Tetracycline, Penicillin and 50% to Amoxicillin while 100% and 92.9% show MIC > 16ug/ml to Amoxicillin, Tetracycline and Penicillin respectively. Similarly, 100% resistance to Tetracycline and Penicillin was shown by the S. aureus obtained ...

  3. Detection of bacterial blight resistant gene xa5 using linked marker ...

    African Journals Online (AJOL)

    USER

    2010-06-14

    Jun 14, 2010 ... important recessive bacterial blight resistant gene, which is effective and important in Asian rice breeding program. It was also used in combination by incorporation with various recessive and dominant BB resistant genes. The purpose of our study was to identify the bacterial blight resistant genes xa5 in ...

  4. Occurrence of integrons and antimicrobial resistance genes among Salmonella enterica from Brazil

    DEFF Research Database (Denmark)

    Peirano, G.; Agersø, Yvonne; Aarestrup, Frank Møller

    2006-01-01

    Objectives: To determine the occurrence of antimicrobial resistance genes and role of integrons among 135 anti microbial-resistant Salmonella enterica from Brazil. Methods: The presence of antimicrobial resistance genes, class 1 and 2 integrons and gene cassettes was analysed by PCR and sequencing...

  5. Antimicrobial susceptibility and occurrence of resistance genes among Salmonella enterica serovar Weltevreden from different countries

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Lertworapreecha, M.; Evans, M.C.

    2003-01-01

    and gentamicin. All nine ampicillin-resistant isolates contained a sequence similar to the bla(TEM-1b) gene, one of the eight chloramphenicol-resistant isolates a sequence similar to the catA1 gene, all three neomycin-resistant isolates a sequence similar to the aphA-2 gene, 16 (73%) of the 22 streptomycin...

  6. Resistance of Antimicrobial Peptide Gene Transgenic Rice to Bacterial Blight

    Directory of Open Access Journals (Sweden)

    Wei WANG

    2011-03-01

    Full Text Available Antimicrobial peptide is a polypeptide with antimicrobial activity. Antimicrobial peptide genes Np3 and Np5 from Chinese shrimp (Fenneropenaeus Chinensis were integrated into Oryza sativa L. subsp. japonica cv. Aichi ashahi by Agrobacterium mediated transformation system. PCR analysis showed that the positive ratios of Np3 and Np5 were 36% and 45% in T0 generation, respectively. RT-PCR analysis showed that the antimicrobial peptide genes were expressed in T1 generation, and there was no obvious difference in agronomic traits between transgenic plants and non-transgenic plants. Four Np3 and Np5 transgenic lines in T1 generation were inoculated with Xanthomonas oryzae pv. oryzae strain CR4, and all the four transgenic lines had significantly enhanced resistance to bacterial blight caused by the strain CR4. The Np5 transgenic lines also showed higher resistance to bacterial blight caused by strains JS97-2, Zhe 173 and OS-225. It is suggested that transgenic lines with Np5 gene might possess broad spectrum resistance to rice bacterial blight.

  7. A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost.

    Science.gov (United States)

    Han, Heping; Vila-Aiub, Martin M; Jalaludin, Adam; Yu, Qin; Powles, Stephen B

    2017-12-01

    A novel glyphosate resistance double point mutation (T102I/P106S, TIPS) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene has been recently identified for the first time only in the weed species Eleusine indica. Quantification of plant resistance cost associated with the TIPS and the often reported glyphosate resistance single P106S mutation was performed. A significant resistance cost (50% in seed number currency) associated with the homozygous TIPS but not the homozygous P106S EPSPS variant was identified in E. indica plants. The resistance cost associated with the TIPS mutation escalated to 85% in plants under resource competition with rice crops. The resistance cost was not detected in nonhomozygous TIPS plants denoting the recessive nature of the cost associated with the TIPS allele. An excess of 11-fold more shikimate and sixfold more quinate in the shikimate pathway was detected in TIPS plants in the absence of glyphosate treatment compared to wild type, whereas no changes in these compounds were observed in P106S plants when compared to wild type. TIPS plants show altered metabolite levels in several other metabolic pathways that may account for the expression of the observed resistance cost. © 2017 John Wiley & Sons Ltd.

  8. Molecular evolution of a malaria resistance gene (DARC) in primates.

    Science.gov (United States)

    Oliveira, Thiago Yukio Kikuchi; Harris, Eugene E; Meyer, Diogo; Jue, Chong K; Silva, Wilson Araújo

    2012-07-01

    Genes involved in host-pathogen interactions are often strongly affected by positive natural selection. The Duffy antigen, coded by the Duffy antigen receptor for chemokines (DARC) gene, serves as a receptor for Plasmodium vivax in humans and for Plasmodium knowlesi in some nonhuman primates. In the majority of sub-Saharan Africans, a nucleic acid variant in GATA-1 of the gene promoter is responsible for the nonexpression of the Duffy antigen on red blood cells and consequently resistance to invasion by P. vivax. The Duffy antigen also acts as a receptor for chemokines and is expressed in red blood cells and many other tissues of the body. Because of this dual role, we sequenced a ~3,000-bp region encompassing the entire DARC gene as well as part of its 5' and 3' flanking regions in a phylogenetic sample of primates and used statistical methods to evaluate the nature of selection pressures acting on the gene during its evolution. We analyzed both coding and regulatory regions of the DARC gene. The regulatory analysis showed accelerated rates of substitution at several sites near known motifs. Our tests of positive selection in the coding region using maximum likelihood by branch sites and maximum likelihood by codon sites did not yield statistically significant evidence for the action of positive selection. However, the maximum likelihood test in which the gene was subdivided into different structural regions showed that the known binding region for P. vivax/P. knowlesi is under very different selective pressures than the remainder of the gene. In fact, most of the gene appears to be under strong purifying selection, but this is not evident in the binding region. We suggest that the binding region is under the influence of two opposing selective pressures, positive selection possibly exerted by the parasite and purifying selection exerted by chemokines.

  9. Cloning of novel rice blast resistance genes from two rapidly evolving NBS-LRR gene families in rice.

    Science.gov (United States)

    Guo, Changjiang; Sun, Xiaoguang; Chen,