WorldWideScience

Sample records for streptomycin resistance genes

  1. Plant agricultural streptomycin formulations do not carry antibiotic resistance genes.

    Science.gov (United States)

    Rezzonico, Fabio; Stockwell, Virginia O; Duffy, Brion

    2009-07-01

    Streptomycin is used in plant agriculture for bacterial disease control, particularly against fire blight in pome fruit orchards. Concerns that this may increase environmental antibiotic resistance have led to bans or restrictions on use. Experience with antibiotic use in animal feeds raises the possible influence of formulation-delivered resistance genes. We demonstrate that agricultural streptomycin formulations do not carry producer organism resistance genes. By using an optimized extraction procedure, Streptomyces 16S rRNA genes and the streptomycin resistance gene strA were not detected in agricultural streptomycin formulations. This diminishes the likelihood for one potential factor in resistance development due to streptomycin use.

  2. Streptomycin Resistance and Lineage-Specific Polymorphisms in Mycobacterium tuberculosis gidB Gene

    Science.gov (United States)

    Spies, Fernanda S.; Ribeiro, Andrezza W.; Ramos, Daniela F.; Ribeiro, Marta O.; Martin, Anandi; Palomino, Juan Carlos; Rossetti, Maria Lucia R.; da Silva, Pedro Eduardo A.; Zaha, Arnaldo

    2011-01-01

    Mutations related to streptomycin resistance in the rpsL and rrs genes are well known and can explain about 70% of this phenotypic resistance. Recently, the gidB gene was found to be associated with low-level streptomycin resistance in Mycobacterium tuberculosis. Mutations in gidB have been reported with high frequency, and this gene appears to be very polymorphic, with frameshift and point mutations occurring in streptomycin-susceptible and streptomycin-resistant strains. In this study, mutations in gidB appeared in 27% of streptomycin-resistant strains that contained no mutations in the rpsL or rrs genes, and they were associated with low-level streptomycin resistance. However, the association of certain mutations in gidB with streptomycin resistance needs to be further investigated, as we also found mutations in gidB in streptomycin-susceptible strains. This occurred only when the strain was resistant to rifampin and isoniazid. Two specific mutations appeared very frequently in this and other studies of streptomycin-susceptible and -resistant strains; these mutations were not considered related to streptomycin resistance, but as a polymorphism. We stratified the strains according to the different phylogenetic lineages and showed that the gidB16 polymorphism (16G allele) was exclusively present in the Latin American-Mediterranean (LAM) genotype, while the gidB92 polymorphism (92C allele) was associated with the Beijing lineage in another population. In the sample studied, the two characterized single-nucleotide polymorphisms could distinguish LAM and Beijing lineages from the other lineages. PMID:21593257

  3. Streptomycin resistance and lineage-specific polymorphisms in Mycobacterium tuberculosis gidB gene.

    Science.gov (United States)

    Spies, Fernanda S; Ribeiro, Andrezza W; Ramos, Daniela F; Ribeiro, Marta O; Martin, Anandi; Palomino, Juan Carlos; Rossetti, Maria Lucia R; da Silva, Pedro Eduardo A; Zaha, Arnaldo

    2011-07-01

    Mutations related to streptomycin resistance in the rpsL and rrs genes are well known and can explain about 70% of this phenotypic resistance. Recently, the gidB gene was found to be associated with low-level streptomycin resistance in Mycobacterium tuberculosis. Mutations in gidB have been reported with high frequency, and this gene appears to be very polymorphic, with frameshift and point mutations occurring in streptomycin-susceptible and streptomycin-resistant strains. In this study, mutations in gidB appeared in 27% of streptomycin-resistant strains that contained no mutations in the rpsL or rrs genes, and they were associated with low-level streptomycin resistance. However, the association of certain mutations in gidB with streptomycin resistance needs to be further investigated, as we also found mutations in gidB in streptomycin-susceptible strains. This occurred only when the strain was resistant to rifampin and isoniazid. Two specific mutations appeared very frequently in this and other studies of streptomycin-susceptible and -resistant strains; these mutations were not considered related to streptomycin resistance, but as a polymorphism. We stratified the strains according to the different phylogenetic lineages and showed that the gidB(16) polymorphism (16G allele) was exclusively present in the Latin American-Mediterranean (LAM) genotype, while the gidB(92) polymorphism (92C allele) was associated with the Beijing lineage in another population. In the sample studied, the two characterized single-nucleotide polymorphisms could distinguish LAM and Beijing lineages from the other lineages.

  4. Streptomycin use in apple orchards did not increase abundance of mobile resistance genes.

    Science.gov (United States)

    Duffy, Brion; Holliger, Eduard; Walsh, Fiona

    2014-01-01

    Streptomycin is used as a first-line defense and tetracycline as a second-line defense, in the fight against fire blight disease in apple and pear orchards. We have performed the first study to quantitatively analyze the influence of streptomycin use in agriculture on the abundance of streptomycin and tetracycline resistance genes in apple orchards. Flowers, leaves, and soil were collected from three orchard sites in 2010, 2011, and 2012. Gene abundance distribution was analyzed using two-way anova and principal component analysis to investigate relationships between gene abundance data over time and treatment. The mobile antibiotic resistance genes, strA, strB, tetB, tetM, tetW, and the insertion sequence IS1133, were detected prior to streptomycin treatment in almost all samples, indicating the natural presence of these resistance genes in nature. Statistically significant increases in the resistance gene abundances were occasional, inconsistent, and not reproducible from one year to the next. We conclude that the application of streptomycin in these orchards was not associated with sustained increases in streptomycin or tetracycline resistance gene abundances. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  5. Influence of Soil Use on Prevalence of Tetracycline, Streptomycin, and Erythromycin Resistance and Associated Resistance Genes

    Science.gov (United States)

    Rzeczycka, Marzenna; Miernik, Antoni; Krawczyk-Balska, Agata; Walsh, Fiona; Duffy, Brion

    2012-01-01

    This study examined differences in antibiotic-resistant soil bacteria and the presence and quantity of resistance genes in soils with a range of management histories. We analyzed four soils from agricultural systems that were amended with manure from animals treated with erythromycin and exposed to streptomycin and/or oxytetracycline, as well as non-manure-amended compost and forest soil. Low concentrations of certain antibiotic resistance genes were detected using multiplex quantitative real-time PCR (qPCR), with tet(B), aad(A), and str(A) each present in only one soil and tet(M) and tet(W) detected in all soils. The most frequently detected resistance genes were tet(B), tet(D), tet(O), tet(T), and tet(W) for tetracycline resistance, str(A), str(B), and aac for streptomycin resistance, and erm(C), erm(V), erm(X), msr(A), ole(B), and vga for erythromycin resistance. Transposon genes specific for Tn916, Tn1549, TnB1230, Tn4451, and Tn5397 were detected in soil bacterial isolates. The MIC ranges of isolated bacteria for tetracycline, streptomycin, and erythromycin were 8 to >256 μg/ml, 6 to >1,024 μg/ml, and 0.094 to >256 μg/ml, respectively. Based on 16S rRNA gene similarity, isolated bacteria showed high sequence identity to genera typical of soil communities. Bacteria with the highest MICs were detected in manure-amended soils or soils from agricultural systems with a history of antibiotic use. Non-manure-amended soils yielded larger proportions of antibiotic-resistant bacteria, but these had lower MICs, carried fewer antibiotic resistance genes, and did not display multidrug resistance (MDR). PMID:22203596

  6. Influence of soil use on prevalence of tetracycline, streptomycin, and erythromycin resistance and associated resistance genes.

    Science.gov (United States)

    Popowska, Magdalena; Rzeczycka, Marzenna; Miernik, Antoni; Krawczyk-Balska, Agata; Walsh, Fiona; Duffy, Brion

    2012-03-01

    This study examined differences in antibiotic-resistant soil bacteria and the presence and quantity of resistance genes in soils with a range of management histories. We analyzed four soils from agricultural systems that were amended with manure from animals treated with erythromycin and exposed to streptomycin and/or oxytetracycline, as well as non-manure-amended compost and forest soil. Low concentrations of certain antibiotic resistance genes were detected using multiplex quantitative real-time PCR (qPCR), with tet(B), aad(A), and str(A) each present in only one soil and tet(M) and tet(W) detected in all soils. The most frequently detected resistance genes were tet(B), tet(D), tet(O), tet(T), and tet(W) for tetracycline resistance, str(A), str(B), and aac for streptomycin resistance, and erm(C), erm(V), erm(X), msr(A), ole(B), and vga for erythromycin resistance. Transposon genes specific for Tn916, Tn1549, TnB1230, Tn4451, and Tn5397 were detected in soil bacterial isolates. The MIC ranges of isolated bacteria for tetracycline, streptomycin, and erythromycin were 8 to >256 μg/ml, 6 to >1,024 μg/ml, and 0.094 to >256 μg/ml, respectively. Based on 16S rRNA gene similarity, isolated bacteria showed high sequence identity to genera typical of soil communities. Bacteria with the highest MICs were detected in manure-amended soils or soils from agricultural systems with a history of antibiotic use. Non-manure-amended soils yielded larger proportions of antibiotic-resistant bacteria, but these had lower MICs, carried fewer antibiotic resistance genes, and did not display multidrug resistance (MDR).

  7. Streptomycin and chloramphenicol resistance genes in Escherichia coli isolates from cattle, pigs, and chicken in Kenya.

    Science.gov (United States)

    Kikuvi, G M; Schwarz, S; Ombui, J N; Mitema, E S; Kehrenberg, C

    2007-01-01

    The aims of this study were to determine the genetic basis of streptomycin and chloramphenicol resistance in 30 Escherichia coli isolates from food animals in Kenya and the role of plasmids in the spread of the resistance. Seven of the 29 streptomycin-resistant isolates harbored both the strA and strB genes. Twenty-one of isolates had the strA, strB, and aadA1 genes. The strA gene was disrupted by a functional trimethoprim gene, dfrA14 in 10 of the 21 isolates harboring the three streptomycin resistance genes. Physical linkage of intact strA and sul2 genes was found in two different plasmids from four isolates. Linkage of cassette-borne aadA1 and dfrA1 genes in class 1 integrons was found in two of the isolates. Chloramphenicol resistance was due to the gene catA1 in all the chloramphenicol resistant isolates. The strB, strA, and catA1 genes were transferable by conjugation and this points to the significance of conjugative resistance plasmids in the spread and persistence of streptomycin and chloramphenicol resistance in food animals in Kenya.

  8. Mutations in Streptomycin Resistance Genes and Their Relationship to Streptomycin Resistance and Lineage ofMycobacterium tuberculosisThai Isolates.

    Science.gov (United States)

    Hlaing, Yin Moe; Tongtawe, Pongsri; Tapchaisri, Pramuan; Thanongsaksrikul, Jeeraphong; Thawornwan, Unchana; Archanachan, Buppa; Srimanote, Potjanee

    2017-04-01

    Streptomycin (SM) is recommended by the World Health Organization (WHO) as a part of standard regimens for retreating multidrug-resistant tuberculosis (MDR-TB) cases. The incidence of MDR-TB in retreatment cases was 19% in Thailand. To date, information on SM resistance (SMR) gene mutations correlated to the SMR of Mycobacterium tuberculosis Thai isolates is limited. In this study, the mutations in rpsL , rrs , gidB , and whiB7 were investigated and their association to SMR and the lineage of M. tuberculosis were explored. The lineages of 287 M. tuberculosis collected from 2007 to 2011 were identified by spoligotyping. Drug susceptibility profiles were evaluated by the absolute concentration method. Mutations in SMR genes of 46 SM-resistant and 55 SM-susceptible isolates were examined by DNA sequencing. Three rpsL (Lys43Arg, Lys88Arg, and Lys88Thr) and two gidB (Trp45Ter and Gly69Asp) mutations were present exclusively in the SM resistant M. tuberculosis . Lys43Arg rpsL was the most predominant SMR mutations (69.6%) and prevailed among Beijing isolates (presistant isolates lacking rpsL and rrs mutations. The significance of the three gidB mutations, 276A>C, 615A>G, and 330G>T, as lineage signatures for Beijing and EAI were underscored. This study identified 423G>A gidB as a novel sub-lineage marker for EAI6-BGD1. Our study suggested that the majority of SMR in M. tuberculosis Thai isolates were responsible by rpsL and gidB polymorphisms constantly providing the novel lineage specific makers.

  9. Prevalence of streptomycin resistance genes in bacterial populations in European habitats

    NARCIS (Netherlands)

    Overbeek, van L.S.; Wellington, E.M.H.; Karagouni, A.; Smalla, K.; Collard, J.M.; Elsas, van J.D.

    2002-01-01

    The prevalence of selected streptomycin (Sm)-resistance genes, i.e. aph (3''), aph (6)-1d, aph (6)-1c, ant (3'') and ant (6), was assessed in a range of pristine as well as polluted European habitats. These habitats included bulk and rhizosphere soils, manure from farm animals, activated sludge from

  10. Mechanisms of Streptomycin Resistance: Selection of Mutations in the 16S rRNA Gene Conferring Resistance

    Science.gov (United States)

    Springer, Burkhard; Kidan, Yishak G.; Prammananan, Therdsak; Ellrott, Kerstin; Böttger, Erik C.; Sander, Peter

    2001-01-01

    Chromosomally acquired streptomycin resistance is frequently due to mutations in the gene encoding the ribosomal protein S12, rpsL. The presence of several rRNA operons (rrn) and a single rpsL gene in most bacterial genomes prohibits the isolation of streptomycin-resistant mutants in which resistance is mediated by mutations in the 16S rRNA gene (rrs). Three strains were constructed in this investigation: Mycobacterium smegmatis rrnB, M. smegmatis rpsL3+, and M. smegmatis rrnB rpsL3+. M. smegmatis rrnB carries a single functional rrn operon, i.e., rrnA (comprised of 16S, 23S, and 5S rRNA genes) and a single rpsL+ gene; M. smegmatis rpsL3+ is characterized by the presence of two rrn operons (rrnA and rrnB) and three rpsL+ genes; and M. smegmatis rrnB rpsL3+ carries a single functional rrn operon (rrnA) and three rpsL+ genes. By genetically altering the number of rpsL and rrs alleles in the bacterial genome, mutations in rrs conferring streptomycin resistance could be selected, as revealed by analysis of streptomycin-resistant derivatives of M. smegmatis rrnB rpsL3+. Besides mutations well known to confer streptomycin resistance, novel streptomycin resistance conferring mutations were isolated. Most of the mutations were found to map to a functional pseudoknot structure within the 530 loop region of the 16S rRNA. One of the mutations observed, i.e., 524G→C, severely distorts the interaction between nucleotides 524G and 507C, a Watson-Crick interaction which has been thought to be essential for ribosome function. The use of the single rRNA allelic M. smegmatis strain should help to elucidate the principles of ribosome-drug interactions. PMID:11557484

  11. Novel streptomycin and spectinomycin resistance gene as a gene cassette within a class 1 integron isolated from Escherichia coli

    DEFF Research Database (Denmark)

    Sandvang, D.

    1999-01-01

    The aadA genes, encoding resistance to streptomycin and spectinomycin, have been found as gene cassettes in different gram-negative and gram-positive bacterial species. The present study has revealed the sequence of a new gene, aadA5, integrated as a gene cassette together with the trimethoprim...... resistance gene dfr7 in a class 1 integron. The integron was located on a plasmid and was identified in a pathogenic porcine Escherichia coli isolate....

  12. Novel Streptomycin and Spectinomycin Resistance Gene as a Gene Cassette within a Class 1 Integron Isolated from Escherichia coli

    Science.gov (United States)

    Sandvang, Dorthe

    1999-01-01

    The aadA genes, encoding resistance to streptomycin and spectinomycin, have been found as gene cassettes in different gram-negative and gram-positive bacterial species. The present study has revealed the sequence of a new gene, aadA5, integrated as a gene cassette together with the trimethoprim resistance gene dfr7 in a class 1 integron. The integron was located on a plasmid and was identified in a pathogenic porcine Escherichia coli isolate. PMID:10582907

  13. Mutations in the rpsL gene are involved in streptomycin resistance in Campylobacter coli.

    Science.gov (United States)

    Olkkola, Satu; Juntunen, Pekka; Heiska, Helmi; Hyytiäinen, Heidi; Hänninen, Marja-Liisa

    2010-06-01

    To characterize the mechanisms of streptomycin (STR) resistance in Campylobacter coli, we chose 17 isolates that were resistant to STR, erythromycin (ERY), or both, and the putative STR resistance target genes rpsL, rrs, and gidB were analyzed for mutations. The presence of the aadE gene encoding aminoglycoside 6-adenylyltransferase was also evaluated. To reveal putative connection between ERY and STR resistance mechanisms, 13 C. coli isolates initially susceptible to STR and ERY were exposed to STR, and resistant variants were characterized. We also assessed the development of ERY resistance with a similar method. Finally, the effect of the putative CmeABC efflux pump inhibitor phenyl-arginine-beta-naphthylamine on STR resistance was tested. Our studies showed an association between mutations in the rpsL gene and STR resistance in C. coli. Further, mutations obtained in vitro were more diverse than those occurring in vivo. However, we observed no resistance associated mutations in the other genes studied, and selection with STR did not result in variants resistant to ERY and vice versa. None of the isolates harbored the aadE gene, and no differences in STR minimum inhibitory concentration levels were detected in the presence or absence of phenyl-arginine-beta-naphthylamine. In conclusion, we found that STR resistance was associated with mutations in the rpsL gene, but no obvious association between STR and ERY resistance mechanisms was found in C. coli.

  14. Versatile nourseothricin and streptomycin/spectinomycin resistance gene cassettes and their use in chromosome integration vectors.

    Science.gov (United States)

    Lehman, Stephanie S; Mladinich, Katherine M; Boonyakanog, Angkana; Mima, Takehiko; Karkhoff-Schweizer, RoxAnn R; Schweizer, Herbert P

    2016-10-01

    An obstacle for the development of genetic systems for many bacteria is the limited number of antibiotic selection markers, especially for bacteria that are intrinsically antibiotic resistant or where utilization of such markers is strictly regulated. Here we describe the development of versatile cassettes containing nourseothricin, streptomycin/spectinomycin, and spectinomycin selection markers. The antibiotic resistance genes contained on these cassettes are flanked by loxP sites with allow their in vivo excision from the chromosome of target bacteria using Cre recombinase. The respective selection marker cassettes were used to derive mini-Tn7 elements that can be used for single-copy insertion of genes into bacterial chromosomes. The utility of the selection markers was tested by insertion of the resulting mini-Tn7 elements into the genomes of Burkholderia thailandensis and B. pseudomallei efflux pump mutants susceptible to aminoglycosides, aminocyclitols, and streptothricins, followed by Cre-mediated antibiotic resistance marker excision. The versatile nourseothricin, streptomycin/spectinomycin and spectinomycin resistance loxP cassette vectors described here extend the repertoire of antibiotic selection markers for genetic manipulation of diverse bacteria that are susceptible to aminoglycosides and aminocyclitols. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Distribution of tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae isolated from dairy and nondairy farm soils.

    Science.gov (United States)

    Srinivasan, Velusamy; Nam, Hyang-Mi; Sawant, Ashish A; Headrick, Susan I; Nguyen, Lien T; Oliver, Stephen P

    2008-02-01

    The prevalence of selected tetracycline and streptomycin resistance genes and class 1 integrons in Enterobacteriaceae (n = 80) isolated from dairy farm soil and nondairy soils was evaluated. Among 56 bacteria isolated from dairy farm soils, 36 (64.3%) were resistant to tetracycline, and 17 (30.4%) were resistant to streptomycin. Lower frequencies of tetracycline (9 of 24 or 37.5%) and streptomycin (1 of 24 or 4.2%) resistance were observed in bacteria isolated from nondairy soils. Bacteria (n = 56) isolated from dairy farm soil had a higher frequency of tetracycline resistance genes including tetM (28.6%), tetA (21.4%), tetW (8.9%), tetB (5.4%), tetS (5.4%), tetG (3.6%), and tetO (1.8%). Among 24 bacteria isolated from nondairy soils, four isolates carried tetM, tetO, tetS, and tetW in different combinations; whereas tetA, tetB, and tetG were not detected. Similarly, a higher prevalence of streptomycin resistance genes including strA (12.5%), strB (12.5%), ant(3'') (12.5), aph(6)-1c (12.5%), aph(3'') (10.8%), and addA (5.4%) was detected in bacteria isolated from dairy farm soils than in nondairy soils. None of the nondairy soil isolates carried aadA gene. Other tetracycline (tetC, tetD, tetE, tetK, tetL, tetQ, and tetT) and streptomycin (aph(6)-1c and ant(6)) resistance genes were not detected in both dairy and nondairy soil isolates. A higher distribution of multiple resistance genes was observed in bacteria isolated from dairy farm soil than in nondairy soil. Among 36 tetracycline- and 17 streptomycin-resistant isolates from dairy farm soils, 11 (30.6%) and 9 (52.9%) isolates carried multiple resistance genes encoding resistance to tetracycline and streptomycin, respectively, which was higher than in bacteria isolated from nondairy soils. One strain each of Citrobacter freundii and C. youngae isolated from dairy farm soils carried class 1 integrons with different inserted gene cassettes. Results of this small study suggest that the presence of multiple

  16. Presence of STRA-STRB linked streptomycin-resistance genes in clinical isolate of Escherichia coil 2418.

    Science.gov (United States)

    Ben-Mahrez, K; Sioud, M

    2010-01-01

    The streptomycin resistance of Escherichia coli 2418 strain has been shown to be associated with a 1.2-kb DNA fragment found in the naturally occurring plasmid R2418S. Here, nucleotide sequence analysis of the 1.2-kb DNA fragment revealed the presence of the strB gene which is located immediately downstream of the strA gene. Both sequences are identical to those of strA and strB genes in plasmid RSF1010. Thus, the observed resistance in the clinical isolate is due to the presence of strA-strB genes encoding streptomycin-modifying enzymes. The sequence downstream of strB gene showed a perfect homology with that of RSF1010. In addition, it contained the right inverted repeat of the transposon Tn5393 that has been suggested to be a relic of this transposon found in DNA plasmids isolated from human- and animal-associated bacteria.

  17. Analysis of rpsL and rrs genes mutations related to streptomycin resistance in Mdr and Xdr clinical isolates of Mycobacterium tuberculosis.

    Science.gov (United States)

    Arjomandzadegan, Mohammad; Gravand, Somayeh

    2015-01-01

    Streptomycin is a bactericidal and aminoglycoside antibiotic. It is one of the most effective drugs for treatment of multi-drug Tuberculosis disease. Incidence of resistance is increasingly reported. Its action mechanism is by inhibition of binding aminoacyl tRNA to position "A" in elongation phase, which finally it causes to stop bacterial protein synthesis. In this study, resistance rapid investigation to streptomycin was conducted in clinical strains of Mycobacterium tuberculosis. In this study, among 105 strains of phlegm-positive and culture-positive Mycobacterium tuberculosis, 45 strains of resistant and sensitive to streptomycin were selected for possible mutations examination in genes rrs and rpsL. Specific primers that used for PCR were named rpsL 1, rpsL 2 and rrsR, Frrs. PCR products were sequenced. PCR Products represents 504 bp band for gene rpsL and 1027 bp for gene rrs that shows proper selection of primers and determining an amplification appropriate program. From 26 resistant strains to streptomycin 26 strain have mutation in rpsL gene and 1 strain have alteration in rrs gene. In this study 19 strains were sensitive to streptomycin that have no mutation in these gene. Streptomycin resistance is mainly related to mutation at codons 43 and 88 "rpsL" gene and to a lesser extent "rrs" that are the greatest cause of drug resistance to streptomycin.

  18. Novel missense mutations in gidB gene associated with streptomycin resistance in Mycobacterium tuberculosis: insights from molecular dynamics.

    Science.gov (United States)

    Pandey, Bharati; Grover, Sonam; Goyal, Sukriti; Jamal, Salma; Singh, Aditi; Kaur, Jagdeep; Grover, Abhinav

    2018-01-04

    Streptomycin was the first antibiotic used for the treatment of tuberculosis by inhibiting translational proof reading. Point mutation in gidB gene encoding S-adenosyl methionine (SAM)-dependent 7-methylguanosine (m7G) methyltransferase required for methylation of 16S rRNA confers streptomycin resistance. As there was no structural substantiation experimentally, gidB protein model was built by threading algorithm. In this work, molecular dynamics (MD) simulations coupled with binding free energy calculations were performed to outline the mechanism underlying high-level streptomycin resistance associated with three novel missense mutants including S70R, T146M, and R187M. Results from dynamics analyses suggested that the structure distortion in the binding pocket of gidB mutants modulate SAM binding affinity. At the structural level, these conformational changes bring substantial decrease in the number of residues involved in hydrogen bonding and dramatically reduce thermodynamic stability of mutant gidB-SAM complexes. The outcome of comparative analysis of the MD simulation trajectories revealed lower conformational stability associated with higher flexibility in mutants relative to the wild-type, turns to be major factor driving the emergence of drug resistance toward antibiotic. This study will pave way toward design and development of resistant defiant gidB inhibitors as potent anti-TB agents.

  19. Real-time PCR methods for quantitative monitoring of streptomycin and tetracycline resistance genes in agricultural ecosystems.

    Science.gov (United States)

    Walsh, F; Ingenfeld, A; Zampicolli, M; Hilber-Bodmer, M; Frey, J E; Duffy, B

    2011-08-01

    Antibiotic application in plant agriculture is primarily used to control fire blight caused by Erwinia amylovora in pome fruit orchards. In order to facilitate environmental impact assessment for antibiotic applications, we developed and validated culture-independent quantitative real-time PCR multiplex assays for streptomycin (strA, strB, aadA and insertion sequence IS1133) and tetracycline (tetB, tetM and tetW) resistance elements in plant and soil samples. The qPCR were reproducible and consistent whether the DNA was extracted directly from bacteria, plant and soil samples inoculated with bacteria or soil samples prior to and after manure slurry treatment. The genes most frequently identified in soils pre- and post-slurry treatment were strB, aadA, tetB and tetM. All genes tested were detected in soils pre-slurry treatment, and a decrease in relative concentrations of tetB and the streptomycin resistance genes was observed in samples taken post-slurry treatment. These multiplex qPCR assays offer a cost-effective, reliable method for simultaneous quantification of antibiotic resistance genes in complex, environmental sample matrices. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Molecular Mechanisms of Intrinsic Streptomycin Resistance in Mycobacterium abscessus.

    Science.gov (United States)

    Dal Molin, Michael; Gut, Myriam; Rominski, Anna; Haldimann, Klara; Becker, Katja; Sander, Peter

    2018-01-01

    Streptomycin, the first drug used for the treatment of tuberculosis, shows limited activity against the highly resistant pathogen Mycobacterium abscessus We recently identified two aminoglycoside-acetylating genes [ aac(2') and eis2 ] which, however, do not affect susceptibility to streptomycin. This suggests the existence of a discrete mechanism of streptomycin resistance. M. abscessus BLASTP analysis identified MAB_2385 as a close homologue of the 3″- O -phosphotransferase [APH(3″)] from the opportunistic pathogen Mycobacterium fortuitum as a putative streptomycin resistance determinant. Heterologous expression of MAB_2385 in Mycobacterium smegmatis increased the streptomycin MIC, while the gene deletion mutant M. abscessus ΔMAB_2385 showed increased streptomycin susceptibility. The MICs of other aminoglycosides were not altered in M. abscessus ΔMAB_2385. This demonstrates that MAB_2385 encodes a specific and prime innate streptomycin resistance determinant in M. abscessus We further explored the feasibility of applying rpsL -based streptomycin counterselection to generate gene deletion mutants in M. abscessus Spontaneous streptomycin-resistant mutants of M. abscessus ΔMAB_2385 were selected, and we demonstrated that the wild-type rpsL is dominant over the mutated rpsL K43R in merodiploid strains. In a proof of concept study, we exploited this phenotype for construction of a targeted deletion mutant, thereby establishing an rpsL -based counterselection method in M. abscessus . Copyright © 2017 American Society for Microbiology.

  1. Functional genomics in Campylobacter coli identified a novel streptomycin resistance gene located in a hypervariable genomic region.

    Science.gov (United States)

    Olkkola, Satu; Culebro, Alejandra; Juntunen, Pekka; Hänninen, Marja-Liisa; Rossi, Mirko

    2016-07-01

    Numerous aminoglycoside resistance genes have been reported in Campylobacter spp. often resembling those from Gram-positive bacterial species and located in transferable genetic elements with other resistance genes. We discovered a new streptomycin (STR) resistance gene in Campylobactercoli showing 27-34 % amino acid identity to aminoglycoside 6-nucleotidyl-transferases described previously in Campylobacter. STR resistance was verified by gene expression and insertional inactivation. This ant-like gene differs from the previously described aminoglycoside resistance genes in Campylobacter spp. in several aspects. It does not appear to originate from Gram-positive bacteria and is located in a region corresponding to a previously described hypervariable region 14 of C. jejuni with no other known resistance genes detected in close proximity. Finally, it does not belong to a multiple drug resistance plasmid or transposon. This novel ant-like gene appears widely spread among C. coli as it is found in strains originating both from Europe and the United States and from several, apparently unrelated, hosts and environmental sources. The closest homologue (60 % amino acid identity) was found in certain C. jejuni and C. coli strains in a similar genomic location, but an association with STR resistance was not detected. Based on the findings presented here, we hypothesize that Campylobacter ant-like gene A has originated from a common ancestral proto-resistance element in Campylobacter spp., possibly encoding a protein with a different function. In conclusion, whole genome sequencing allowed us to fill in a knowledge gap concerning STR resistance in C. coli by revealing a novel STR resistance gene possibly inherent to Campylobacter.

  2. Plant Agricultural Streptomycin Formulations Do Not Carry Antibiotic Resistance Genes▿

    OpenAIRE

    Rezzonico, Fabio; Stockwell, Virginia O.; Duffy, Brion

    2009-01-01

    Streptomycin is used in plant agriculture for bacterial disease control, particularly against fire blight in pome fruit orchards. Concerns that this may increase environmental antibiotic resistance have led to bans or restrictions on use. Experience with antibiotic use in animal feeds raises the possible influence of formulation-delivered resistance genes. We demonstrate that agricultural streptomycin formulations do not carry producer organism resistance genes. By using an optimized extracti...

  3. Host-dependent transposon Tn5-mediated streptomycin resistance.

    OpenAIRE

    De Vos, G F; Finan, T M; Signer, E R; Walker, G C

    1984-01-01

    Transposon Tn5 encodes streptomycin resistance in addition to kanamycin-neomycin resistance. This resistance was not detectable in Escherichia coli but was efficiently expressed in Rhizobium meliloti and certain other strains. By analysis of cloned Tn5 restriction endonuclease fragments, the streptomycin resistance (str) gene was located in the right-hand side of the central region as the transposon is conventionally drawn. Transcription of str appeared to originate at pL, the promoter for th...

  4. A large conjugative Acinetobacter baumannii plasmid carrying the sul2 sulphonamide and strAB streptomycin resistance genes.

    Science.gov (United States)

    Hamidian, Mohammad; Ambrose, Stephanie J; Hall, Ruth M

    Acinetobacter baumannii is an important nosocomial pathogen that often complicates treatment because of its high level of resistance to antibiotics. Though plasmids can potentially introduce various genes into bacterial strains, compared to other Gram-negative bacteria, information about the unique A. baumannii plasmid repertoire is limited. Here, whole genome sequence data was used to determine the plasmid content of strain A297 (RUH875), the reference strain for the globally disseminated multiply resistant A. baumannii clone, global clone 1(GC1). A297 contains three plasmids. Two known plasmids were present; one, pA297-1 (pRAY*), carries the aadB gentamicin, kanamycin and tobramycin resistance gene and another is an 8.7kb cryptic plasmid often found in GC1 isolates. The third plasmid, pA297-3, is 200kb and carries the sul2 sulphonamide resistance gene and strAB streptomycin resistance gene within Tn6172 and a mer mercuric ion resistance module elsewhere. pA297-3 transferred sulphonamide, streptomycin and mercuric ion resistance at high frequency to a susceptible A. baumannii recipient, and contains several genes potentially involved in conjugative transfer. However, a relaxase gene was not found. It also includes several genes encoding proteins involved in DNA metabolism such as partitioning. However, a gene encoding a replication initiation protein could not be found. pA297-3 includes two copies of a Miniature Inverted-Repeat Transposable Element (MITE), named MITE-297, bracketing a 77.5kb fragment, which contains several IS and the mer module. Several plasmids related to but smaller than pA297-3 were found in the GenBank nucleotide database. They were found in different A. baumannii clones and are wide spread. They all contain either Tn6172 or a variant in the same position in the backbone as Tn6172 in pA297-3. Some related plasmids have lost the segment between the MITE-297 copies and retain only one MITE-297. Others have segments of various lengths between

  5. A suitable streptomycin-resistant mutant for constructing unmarked in-frame gene deletions using rpsL as a counter-selection marker.

    Science.gov (United States)

    Tsai, Yu-Kuo; Liou, Ci-Hong; Lin, Jung-Chung; Ma, Ling; Fung, Chang-Phone; Chang, Feng-Yee; Siu, L Kristopher

    2014-01-01

    The streptomycin counter-selection system is a useful tool for constructing unmarked in-frame gene deletions, which is a fundamental approach to study bacteria and their pathogenicity at the molecular level. A prerequisite for this system is acquiring a streptomycin-resistant strain due to rpsL mutations, which encodes the ribosomal protein S12. However, in this study no streptomycin resistance was found to be caused by rpsL mutations in all 127 clinical strains of Klebsiella pneumoniae isolated from liver abscess patients. By screening 107 spontaneous mutants of streptomycin resistance from a clinical strain of K. pneumoniae, nucleotide substitution or insertion located within the rpsL was detected in each of these strains. Thirteen different mutants with varied S12 proteins were obtained, including nine streptomycin-dependent mutants. The virulence of all four streptomycin-resistant mutants was further evaluated. Compared with the parental strain, the K42N, K42T and K87R mutants showed a reduction in growth rate, and the K42N and K42T mutants became susceptible to normal human serum. In the mice LD50 (the bacterial dose that caused 50% death) assay, the K42N and K42T mutants were ∼ 1,000-fold less lethal (∼ 2 × 10(5) CFU) and the K87R mutant was ∼ 50-fold less lethal (∼ 1 × 10(4) CFU) than the parental strain (∼ 2 × 10(2) CFU). A K42R mutant showed non-observable effects on the above assays, while this mutant exhibited a small cost (P streptomycin resistance caused by rpsL mutations are less virulent than their parental strain in the absence of streptomycin. The K42R mutant showed similar pathogenicity to its parental strain and should be one of the best choices when using rpsL as a counter-selection marker.

  6. High-resolution melting facilitates mutation screening of rpsL gene associated with streptomycin resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Wang, Feifei; Shen, Hongbo; Guan, Ming; Wang, Ying; Feng, Yun; Weng, Xinhua; Wang, Honghai; Zhang, Wenhong

    2011-02-20

    Drug resistance remains a serious threat to tuberculosis control worldwide. As one of the important first-line antitubercular agents, resistance to streptomycin (SM) and its derivatives has increased in recent years and has become one of the characteristics of extensively drug-resistant tuberculosis (XDR-TB). A novel rapid assay to screen for rpsL gene mutations associated with SM resistance in Mycobacterium tuberculosis (M. tuberculosis), was developed using high-resolution melting (HRM) analysis. The HRM results of 134 SM-resistant clinical isolates and 20 SM-susceptible clinical isolates of M. tuberculosis for rpsL gene mutations were perfectly matched with those of DNA sequencing. SM resistance was highly associated with rpsL mutations in M. tuberculosis. HRM technique represented an inexpensive, highly sensitive and high-throughput method to facilitate the screening of large numbers of clinical samples for epidemiological studies of drug-resistance of M. tuberculosis, especially in developing countries. Copyright © 2010 Elsevier GmbH. All rights reserved.

  7. Molecular analysis of the rpsL gene for rapid detection of streptomycin-resistant Mycobacterium tuberculosis: a meta-analysis.

    Science.gov (United States)

    He, Jing; Zhu, Baosheng; Yang, Zhaojie; Hu, Binbin; Lin, Lianbing; Zhang, Qi

    2014-08-01

    Drug-resistant Mycobacterium tuberculosis (MTB) is a major threat to tuberculosis (TB) control programs and public health. Most conventional methods of drug susceptibility testing (DST) are precise but time-consuming. Molecular analysis of the rpsL gene has been used widely in diagnosing streptomycin-resistant MTB since it is rapid and specific. The aim of the present study was to perform a meta-analysis to assess the accuracy of molecular assay of the rpsL gene for the rapid detection of streptomycin-resistant MTB. We searched PubMed, Web of Science, and EBSCO databases for studies that applied a molecular assay of the rpsL gene to detect streptomycin-resistant MTB with a conventional method as the reference. The sensitivity and specificity were pooled by a random effect model using Meta-DiSc software. A summary receiver operating characteristic curve (SROC) was applied to summarize the diagnostic accuracy. A total of 22 studies involving 2618 specimens with 1372 streptomycin-resistant and 1246 streptomycin-susceptible specimens met our inclusion criteria. The overall sensitivity and specificity estimates were 0.64 (95% confidence interval (CI) 0.61-0.66) and 1.00 (95% CI 0.99-1.00), respectively. The area under the SROC curve was 0.9069 and the Cochrane (Q*) index was 0.8387. This meta-analysis reveals that molecular assay of the rpsL gene is a reliable and useful method for the detection of streptomycin-resistant MTB.

  8. Streptomycin-resistant and streptomycin-dependent mutants of the extreme thermophile Thermus thermophilus.

    Science.gov (United States)

    Gregory, S T; Cate, J H; Dahlberg, A E

    2001-06-01

    We have isolated spontaneous streptomycin-resistant, streptomycin-dependent and streptomycin-pseudo-dependent mutants of the thermophilic bacterium Thermus thermophilus IB-21. All mutant phenotypes were found to result from single amino acid substitutions located in the rpsL gene encoding ribosomal protein S12. Spontaneous suppressors of streptomycin dependence were also readily isolated. Thermus rpsL mutations were found to be very similar to rpsL mutations identified in mesophilic organisms. This similarity affords greater confidence in the utility of the crystal structures of Thermus ribosomes to interpret biochemical and genetic data obtained with Escherichia coli ribosomes. In the X-ray crystal structure of the T. thermophilus HB8 30 S subunit, the mutated residues are located in close proximity to one another and to helices 18, 27 and 44 of 16 S rRNA. X-ray crystallographic analysis of ribosomes from streptomycin-resistant, streptomycin-pseudo-dependent and streptomycin-dependent mutants described here is expected to reveal fundamental insights into the mechanism of tRNA selection, translocation, and conformational dynamics of the ribosome. Copyright 2001 Academic Press.

  9. Effect of ribosome-targeting antibiotics on streptomycin-resistant Mycobacterium mutants in the rpsL gene.

    Science.gov (United States)

    Pelchovich, Gidi; Zhuravlev, Alina; Gophna, Uri

    2013-08-01

    Streptomycin (Sm) was the first antibiotic used against Mycobacterium tuberculosis, the aetiological agent of tuberculosis (TB). However, point mutations in the rpsL gene can generate resistance to Sm, which is why spontaneous resistance to this antibiotic emerges so rapidly during treatment. Here we examine the interaction between Sm resistance and sensitivity to other ribosome-targeting antibiotics. Levels of resistance of rpsL mutants to the ribosome-affecting antibiotics chloramphenicol, tetracycline, gentamicin and erythromycin were tested, both singly and in combination. For this purpose, Mycobacterium smegmatis was used, which is commonly used in laboratory experiments as a model for TB. Generally, Sm-resistant mutants were as sensitive to the ribosome-affecting antibiotics as the wild-type strain. Combinations of different ribosome-affecting antibiotics were occasionally more potent than either of the single drugs, with better inhibition of both wild-type and mutant strains. Combining different ribosome-affecting drugs could represent an additional strategy in treating mycobacterial infections, including those resistant to newer drugs such as isoniazid or ethambutol. Copyright © 2013 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  10. pEOC01: a plasmid from Pediococcus acidilactici which encodes an identical streptomycin resistance (aadE) gene to that found in Campylobacter jejuni.

    Science.gov (United States)

    O'Connor, E B; O'Sullivan, O; Stanton, C; Danielsen, M; Simpson, P J; Callanan, M J; Ross, R P; Hill, C

    2007-09-01

    The complete nucleotide sequence of pEOC01, a plasmid (11,661 bp) from Pediococcus acidilactici NCIMB 6990 encoding resistance to clindamycin, erythromycin, and streptomycin was determined. The plasmid, which also replicates in Lactococcus and Lactobacillus species contains 16 putative open reading frames (ORFs), including regions annotated to encode replication, plasmid maintenance and multidrug resistance functions. Based on an analysis the plasmid replicates via a theta replicating mechanism closely related to those of many larger Streptococcus and Enterococcus plasmids. Interestingly, genes homologous to a toxin/antitoxin plasmid maintenance system are present and are highly similar to the omega-epsilon-zeta operon of Streptococcus plasmids. The plasmid contains two putative antibiotic resistance homologs, an ermB gene encoding erythromycin and clindamycin resistance, and a streptomycin resistance gene, aadE. Of particular note is the aadE gene which holds 100% identity to an aadE gene found in Campylobacter jejuni plasmid but which probably originated from a Gram-positive source. This observation is significant in that it provides evidence for recent horizontal transfer of streptomycin resistance from a lactic acid bacterium to a Gram-negative intestinal pathogen and as such infers a role for such plasmids for dissemination of antibiotic resistance genes possibly in the human gut.

  11. The induction of streptomycin resistance in tomato

    International Nuclear Information System (INIS)

    Jansen, D.E.; Snel, E.A.M.; Akerboom, M.; HiIle, J.

    1990-01-01

    Full text: The aim of the research is to investigate cytoplasmic genetics. For the analysis of organelle transfer and segregation in cybrids the presence of selectable and easily screenable genetic markers on organelles is indispensable. Streptomycin resistance is the best characterised cytoplasmic marker. The resistance is dominant and can be induced by a single basepair change in the chloroplast DNA. Protoplasts were treated with several MNU concentrations directly after isolation. Three months after the protoplast mutagenesis about 600 green colonies were isolated from 28x10 6 treated protoplasts. These colonies were retested several times on streptomycin containing media and approximately 150 colonies remained. We distinguished four classes of streptomycin resistance. Experiments were also done without the use of MNU. By somaclonal variation, only a small quantity of streptomycin resistant colonies was isolated at a 50 fold lower frequency. (author)

  12. Ribosomal resistance of clinical enterococcal to streptomycin isolates.

    OpenAIRE

    Eliopoulos, G M; Farber, B F; Murray, B E; Wennersten, C; Moellering, R C

    1984-01-01

    The mechanism of high-level resistance to streptomycin was studied in 12 clinical isolates of Streptococcus faecalis. Six strains produced streptomycin-modifying enzymes. Each of three enzyme-negative strains tested demonstrated ribosomal resistance to streptomycin. Lack of ribosomal susceptibility is a significant cause of high-level streptomycin resistance among clinical enterococcal isolates.

  13. A suitable streptomycin-resistant mutant for constructing unmarked in-frame gene deletions using rpsL as a counter-selection marker.

    Directory of Open Access Journals (Sweden)

    Yu-Kuo Tsai

    Full Text Available The streptomycin counter-selection system is a useful tool for constructing unmarked in-frame gene deletions, which is a fundamental approach to study bacteria and their pathogenicity at the molecular level. A prerequisite for this system is acquiring a streptomycin-resistant strain due to rpsL mutations, which encodes the ribosomal protein S12. However, in this study no streptomycin resistance was found to be caused by rpsL mutations in all 127 clinical strains of Klebsiella pneumoniae isolated from liver abscess patients. By screening 107 spontaneous mutants of streptomycin resistance from a clinical strain of K. pneumoniae, nucleotide substitution or insertion located within the rpsL was detected in each of these strains. Thirteen different mutants with varied S12 proteins were obtained, including nine streptomycin-dependent mutants. The virulence of all four streptomycin-resistant mutants was further evaluated. Compared with the parental strain, the K42N, K42T and K87R mutants showed a reduction in growth rate, and the K42N and K42T mutants became susceptible to normal human serum. In the mice LD50 (the bacterial dose that caused 50% death assay, the K42N and K42T mutants were ∼ 1,000-fold less lethal (∼ 2 × 10(5 CFU and the K87R mutant was ∼ 50-fold less lethal (∼ 1 × 10(4 CFU than the parental strain (∼ 2 × 10(2 CFU. A K42R mutant showed non-observable effects on the above assays, while this mutant exhibited a small cost (P < 0.01 in an in vitro growth competition experiment. In summary, most of the K. pneumoniae strains with streptomycin resistance caused by rpsL mutations are less virulent than their parental strain in the absence of streptomycin. The K42R mutant showed similar pathogenicity to its parental strain and should be one of the best choices when using rpsL as a counter-selection marker.

  14. Induction of streptomycin resistance in the wild tomato Lycopersicon peruvianum

    NARCIS (Netherlands)

    Jansen, C.E.; Snel, E.A.M.; Akerboom, M.J.E.; Nijkamp, H.J.J.; Hille, J.

    1990-01-01

    A protoplast mutagenesis and cell selection system was used for the isolation of streptomycin resistant Lycopersicon peruvianum colonies. Protoplasts were treated with the mutagen N-nitroso-methylurea and could be regenerated into fertile plants, carrying the streptomycin resistant character.

  15. A study on the mechanism of resistance to streptomycin in ...

    African Journals Online (AJOL)

    11 streptomycin-resistant mutants of Xanthomonas oryzae pv. oryzae were obtained by streptomycin selection. These mutants could grow at 100 μg ml-1 of streptomycin while the wild-type strain (PXO99) could not grow at 2 μg ml-1. Specific primers based on the conserved region of X. oryzae pv. oryzae were designed and ...

  16. Transposon Tn5 encodes streptomycin resistance in nonenteric bacteria.

    OpenAIRE

    O'Neill, E A; Kiely, G M; Bender, R A

    1984-01-01

    Strains of Caulobacter crescentus, Pseudomonas putida, Acinetobacter calcoaceticus, Rhizobium meliloti, and Rhodopseudomonas sphaeroides carrying the kanamycin resistance-encoding transposon Tn5 were 15 to 500 times more resistant to streptomycin than transposon-free strains. The streptomycin resistance determinant, which is separable from the kanamycin resistance determinant of Tn5, was not expressed in Escherichia coli or Klebsiella aerogenes.

  17. A clinical isolate of transposon Tn5 expressing streptomycin resistance in Escherichia coli.

    OpenAIRE

    Genilloud, O; Blázquez, J; Mazodier, P; Moreno, F

    1988-01-01

    The central region of transposon Tn5 carries three antibiotic resistance markers: neo, ble, and str. The str gene codes for a phosphotransferase that inactivates streptomycin. This activity is phenotypically expressed in several gram-negative bacteria but not in Escherichia coli. We identified a Tn5 variant in E. coli clinical isolates that express streptomycin resistance. This transposon carries a 6-base-pair deletion within the str gene, near the 3' end. The same kind of mutation had been p...

  18. Correlation of molecular resistance mechanisms and phenotypic resistance levels in streptomycin-resistant Mycobacterium tuberculosis.

    OpenAIRE

    Meier, A; Sander, P; Schaper, K J; Scholz, M; Böttger, E C

    1996-01-01

    Quantitative susceptibility testing of clinical isolates of streptomycin-resistant Mycobacterium tuberculosis demonstrated that there is a close correlation between the molecular resistance mechanism and the in vitro activity of streptomycin: mutations in rpsL were mainly associated with high-level resistance, mutations in rrs were associated with an intermediate level of resistance, and streptomycin-resistant isolates with wild-type rpsL and rrs exhibited a low-level resistance phenotype. In...

  19. Identification of mutations related to streptomycin resistance in clinical isolates of Mycobacterium tuberculosis and possible involvement of efflux mechanism.

    Science.gov (United States)

    Spies, Fernanda S; da Silva, Pedro E Almeida; Ribeiro, Marta O; Rossetti, Maria Lucia; Zaha, Arnaldo

    2008-08-01

    The MIC for streptomycin in the presence of efflux pump (EP) inhibitors and the sequencing of rpsL, rrs, and gidB genes provided evidence for the possible participation of EP in low-level streptomycin (STR) resistance of some isolates without mutations. Mutation in the gidB gene and an EP could act synergistically to confer low STR resistance.

  20. Identification of a globally distributed clinical streptomycin-resistance plasmid and other resistance determinants in a coastal bay of China.

    Science.gov (United States)

    Zhao, J; Dang, H

    2011-01-01

    To study streptomycin-resistant bacteria isolated from Jiaozhou Bay and their molecular determinants of resistance. Twenty-seven tetracycline-resistant and 49 chloramphenicol-resistant bacterial isolates from surface seawater of Jiaozhou Bay were selected for investigation. More than 88% of these isolates were resistant to streptomycin. Half of the streptomycin-resistant bacteria harboured the strA-strB gene pair, and six isolates carried Tn5393-like transposons by PCR detection. The p9123-related plasmids containing the sul2-strA-strB gene cluster were characterized in two environmental Escherichia coli isolates. Transposon Tn5393 was first identified on a Klebsiella pneumoniae plasmid, which also carried Tn1721, estP and umu genes responsible for antimicrobial and insecticide resistance. Coresistance to streptomycin and tetracycline or chloramphenicol was found with high frequency. p9123-related plasmid and Tn5393 transposon may contribute to the wide distribution and spread of the strA-strB gene pair in Jiaozhou Bay. The detection of streptomycin-resistance plasmid pQ1-1 from Jiaozhou Bay seawater bacteria and human bacterial pathogens from USA indicates its global dissemination and transmission, across different components of the microbiota on earth. Streptomycin resistance can be recognized as an important bioindicator of environmental quality, owing to its association with anthropogenic pollution and the multidrug-resistant microbiota. © 2010 The Authors. Letters in Applied Microbiology © 2010 The Society for Applied Microbiology.

  1. Characterization of mutations in streptomycin-resistant Mycobacterium tuberculosis clinical isolates in the area of Barcelona.

    Science.gov (United States)

    Tudó, Griselda; Rey, Emma; Borrell, Sònia; Alcaide, Fernando; Codina, Gemma; Coll, Pere; Martín-Casabona, Núria; Montemayor, Michel; Moure, Raquel; Orcau, Angels; Salvadó, Margarita; Vicente, Eva; González-Martín, Julià

    2010-11-01

    To determine the proportion and type of mutations in Mycobacterium tuberculosis isolates resistant to streptomycin, and their relationship with the level of resistance and with the epidemiological molecular pattern of the isolates. Sixty-nine streptomycin-resistant isolates from a M. tuberculosis strain collection (1995-2005) from Barcelona were studied. The MIC of streptomycin for each isolate was determined using the proportions method with Middlebrook 7H11 medium. The entire rpsL gene and two specific fragments of the rrs gene (the 530 loop and the 912 region) were sequenced. IS6110-restriction fragment length polymorphism and spoligotyping were performed in each isolate. Twenty-six (26/69, 37.7%) streptomycin-resistant isolates presented a mutation in either the rpsL gene and/or the rrs530 loop, with no mutation in the rrs912 region. Seventeen (24.6%) isolates showed rpsL mutations (codons 43 and 88) associated with high MIC levels. Nine (13.0%) isolates had alterations in the rrs gene (A513T, A513C and C516T). Nineteen isolates (19/64, 29.7%) were classified into seven clusters (containing 2-5 isolates per cluster). Nineteen different spoligotype patterns were found. All the LAM3 spoligotype isolates (10/67, 14.9%) were associated with a C491T change in the rrs gene, being also observed in all LAM3 streptomycin-susceptible isolates. Mutations in the rpsL and rrs genes were detected in 37.7% of streptomycin-resistant M. tuberculosis isolates. High-level resistance was associated with mutations in the rpsL gene, whereas wild-type isolates showed low MIC levels. The presence of the C491T substitution in the rrs gene in streptomycin-susceptible and -resistant isolates demonstrates that this change is an epidemiological marker associated with LAM3 sublineage.

  2. The genetic background for streptomycin resistance in Escherichia coli influences the distribution of MICs.

    Science.gov (United States)

    Sunde, Marianne; Norström, Madelaine

    2005-07-01

    The aim of this study was to investigate the genetic background for streptomycin resistance in Escherichia coli and perform analysis of the MICs in relation to genetic background. The 136 strains investigated, with streptomycin MICs of > or =16 mg/L, originated from meat and meat products and were collected within the frame of the Norwegian monitoring programme for antimicrobial resistance in bacteria from feed, food and animals (NORM-VET). PCR was carried out for detection of the streptomycin resistance genes strA-strB and the integron-associated aadA gene cassettes. The strA-strB genes and/or an aadA gene cassette were detected in 110 of the 136 (80.9%) strains investigated. The strA-strB genes were the most prevalent, and were detected in 90 strains. The aadA gene cassettes were detected in 29 strains, and nine strains harboured both the strA-strB genes and an aadA gene cassette. The distribution of MICs differed considerably between isolates harbouring the strA-strB genes (solely) (MIC(50) = 128 mg/L) and isolates harbouring an aadA gene cassette (solely) (MIC(50) = 16 mg/L). Strains harbouring both the strA-strB genes and an aadA gene cassette had higher streptomycin MICs than those harbouring either alone. The distribution of streptomycin MICs in E. coli can be greatly influenced by the genes encoding resistance to streptomycin. The strA-strB genes are probably involved in conferring high-level resistance to streptomycin, whereas the opposite seems to be the case for the aadA gene cassettes. The low-level streptomycin resistance, caused by the presence of aadA gene cassettes in integrons, represents an obstacle in classifying E. coli as susceptible or resistant to streptomycin. Furthermore, the determination of an epidemiological cut-off value for surveillance purposes is also complicated by dissemination of integrons containing the aadA cassettes.

  3. Gene Cluster Conferring Streptomycin, Sulfonamide, and Tetracycline Resistance in Escherichia coli O157:H7 Phage Types 23, 45, and 67 ▿

    Science.gov (United States)

    Ziebell, K.; Johnson, R. P.; Kropinski, A. M.; Reid-Smith, R.; Ahmed, R.; Gannon, V. P.; Gilmour, M.; Boerlin, P.

    2011-01-01

    Multidrug resistance to streptomycin, sulfonamide, and tetracycline (AMR-SSuT) was identified in 156 of 171 isolates of Escherichia coli O157:H7 of phage types 23, 45, and 67. In 154 AMR-SSuT isolates, resistance was encoded by strA, strB, sul2, and tet(B), which in 59 of 63 tested isolates were found clustered together on the chromosome within the cdiA locus. PMID:21239555

  4. Gene cluster conferring streptomycin, sulfonamide, and tetracycline resistance in Escherichia coli O157:H7 phage types 23, 45, and 67.

    Science.gov (United States)

    Ziebell, K; Johnson, R P; Kropinski, A M; Reid-Smith, R; Ahmed, R; Gannon, V P; Gilmour, M; Boerlin, P

    2011-03-01

    Multidrug resistance to streptomycin, sulfonamide, and tetracycline (AMR-SSuT) was identified in 156 of 171 isolates of Escherichia coli O157:H7 of phage types 23, 45, and 67. In 154 AMR-SSuT isolates, resistance was encoded by strA, strB, sul2, and tet(B), which in 59 of 63 tested isolates were found clustered together on the chromosome within the cdiA locus.

  5. Induction of Streptomycin Uptake in Resistant Strains of Escherichia coli

    Science.gov (United States)

    Höltje, Joachim-Volker

    1979-01-01

    Different streptomycin-resistant strains of Escherichia coli, including an R100 plasmid-carrying strain of E. coli W3110, the ribosomally resistant mutant SM10, and the spontaneous revertant from dependence to independence d1023, exhibited poor accumulation capacity for aminoglycoside antibiotics. This was due to a failure of these mutants to induce the general polyamine transport system that is utilized by streptomycin to enter the cell. It is shown that the aminoglycoside kanamycin, which is effective on these streptomycin-resistant strains, was capable of inducing the uptake of streptomycin, thus giving rise to streptomycin accumulation up to wild-type levels. Plasmid-determined resistance, which has been speculated to be the result of a blockage of the uptake system by modified antibiotic molecules, cannot be overcome by the induction of streptomycin transport. Increase in permeability of the antibiotic does not affect the susceptibility of the bacteria. It is shown that all of the antibiotic taken up was enzymatically modified. R-plasmid-conferred resistance to aminoglycosides is therefore explained by the inactivation of the antibiotic entering the bacterial cell. PMID:371542

  6. Antimicrobial susceptibility of Bifidobacterium breve strains and genetic analysis of streptomycin resistance of probiotic B. breve strain Yakult.

    Science.gov (United States)

    Kiwaki, Mayumi; Sato, Takashi

    2009-09-15

    The minimum inhibitory concentrations (MICs) of 17 antimicrobials for 26 Bifidobacterium breve strains of various origins were determined by broth microdilution. MIC distributions for 17 antimicrobials except streptomycin and tetracycline were unimodal for all strains tested, whereas bimodal distributions were observed for streptomycin and tetracycline. The probiotic strain B. breve strain Yakult showed intrinsic susceptibility to all antimicrobials except streptomycin to which the strain showed an atypically higher MIC of >256 microg/ml. Because this strain is a commercial strain, which is often ingested by many consumers on a daily basis, it is very important to determine the genetic basis for streptomycin resistance of this strain. Molecular analysis revealed that a mutation of the rpsL gene for ribosomal protein S12 was responsible for this streptomycin resistance. The resistance of B. breve strain Yakult to streptomycin, therefore, is caused by a chromosomal mutation and very unlikely to be transferred to other microorganisms.

  7. Kinetic impairment of restrictive streptomycin-resistant ribosomes.

    Science.gov (United States)

    Bohman, K; Ruusala, T; Jelenc, P C; Kurland, C G

    1984-01-01

    Comparisons in vivo and in vitro of wild-type and otherwise isogenic bacteria with five different mutant alleles of the gene (rpsL) specifying ribosomal protein S12, all resistant to high levels of streptomycin, show that the streptomycin-resistant (Smr) phenotype can be subdivided into major groups: restrictive and non-restrictive. The restrictive bacteria have a characteristically lower frequency of nonsense suppression in vivo, and are also slower than the wild type in their rate of protein synthesis. Non-restrictive Smr bacteria on the other hand do not differ significantly from the wild type either in nonsense suppression frequencies or in the rate of translation. A complementary pattern is seen in vitro, where ribosomes from the restrictive Smr bacteria translate poly(U) with a significantly lower missense error frequency than wild-type ribosomes, and also show an increased Michaelis constant (KM) with respect to their substrate, i.e. ternary complexes. Both effects are correlated with the more aggressive proofreading function that is characteristic of these restrictive ribosomes. In contrast, ribosomes isolated from the non-restrictive Smr bacteria do not show any major difference in either proofreading or missense error in vitro when compared to the wild type.

  8. aadA Confers Streptomycin Resistance in Borrelia burgdorferi

    Science.gov (United States)

    Frank, Kristi L.; Bundle, Sharyl F.; Kresge, Michele E.; Eggers, Christian H.; Samuels, D. Scott

    2003-01-01

    To enhance genetic manipulation of the Lyme disease spirochete Borrelia burgdorferi, we assayed the aadA gene for the ability to confer resistance to the antibiotics spectinomycin and streptomycin. Using the previously described pBSV2 as a backbone, a shuttle vector, termed pKFSS1, which carries the aadA open reading frame fused to the B. burgdorferi flgB promoter was constructed. The hybrid flgB promoter-aadA cassette confers resistance to spectinomycin and streptomycin in both B. burgdorferi and Escherichia coli. pKFSS1 has a replication origin derived from the 9-kb circular plasmid and can be comaintained in B. burgdorferi with extant shuttle vector pCE320, which has a replication origin derived from a 32-kb circular plasmid, or pBSV2, despite the fact that pKFSS1 and pBSV2 have the same replication origin. Our results demonstrate the availability of a new selectable marker and shuttle vector for genetically dissecting B. burgdorferi at the molecular level. PMID:14594849

  9. Ribosomal Resistance to Streptomycin and Spectinomycin in Neisseria gonorrhoeae

    Science.gov (United States)

    Maness, Michael J.; Foster, Gayle C.; Sparling, P. Frederick

    1974-01-01

    A cell-free protein synthesizing system was used to study the mechanism of resistance to streptomycin (Str) and spectinomycin (Spc) in laboratory mutants and clinical isolates of Neisseria gonorrhoeae. The 70S ribosomes from sensitive strains were sensitive to the effects of Str and Spc on synthesis directed by several synthetic polynucleotide messengers, whereas 70S ribosomes from resistant strains were resistant to these same effects. In each case, the alteration was localized to the 30S ribosomal subunit by studying antibiotic sensitivities of hybrid 70S ribosomes formed by combining subunits from sensitive and resistant strains. No evidence was found for streptomycin- or spectinomycin-inactivating enzymes. PMID:4279906

  10. GidB mutation as a phylogenetic marker for Q1 cluster Mycobacterium tuberculosis isolates and intermediate-level streptomycin resistance determinant in Lisbon, Portugal.

    Science.gov (United States)

    Perdigão, J; Macedo, R; Machado, D; Silva, C; Jordão, L; Couto, I; Viveiros, M; Portugal, I

    2014-05-01

    Development of streptomycin resistance in Mycobacterium tuberculosis is usually associated with mutations in rpsL and rrs genes, although up to 50% of clinical streptomycin-resistant isolates may present no mutation in either of these genes. In the present report we investigate the role of gidB gene mutations in streptomycin resistance. We have analyzed 52 streptomycin-resistant and 30 streptomycin-susceptible Mycobacterium tuberculosis clinical isolates by sequencing and endonuclease analysis of the gidB and rpsL genes. All clinical isolates were genotyped by 12-loci MIRU-VNTR. The gidB gene of 18 streptomycin-resistant isolates was sequenced and four missense mutations were found: F12L (1/18), L16R (18/18), A80P (4/18) and S100F (18/18). The remaining isolates were screened by endonuclease analysis for mutations A80P in the gidB gene and K43R in the rpsL gene. Overall, mutation A80P in the gidB gene was found in eight streptomycin-resistant isolates and 11 streptomycin-susceptible multidrug-resistant isolates. Also noteworthy, is the fact that gidB mutations were only present in isolates without rpsL and rrs mutations, all from genetic cluster Q1. Streptomycin quantitative drug susceptibility testing showed that isolates carrying the gidB A80P mutation were streptomycin intermediate-level resistant and that standard drug susceptibility testing yielded inconsistent results, probably due to borderline resistance. We conclude that gidB mutations may explain the high number of streptomycin-resistant strains with no mutation in rpsL or rrs. These mutations might occasionally confer low-level streptomycin resistance that will go undetected in standard susceptibility testing. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

  11. A streptomycin resistance marker in H. parasuis based on site-directed mutations in rpsL gene to perform unmarked in-frame mutations and to verify natural transformation

    Directory of Open Access Journals (Sweden)

    Ke Dai

    2018-01-01

    Full Text Available Haemophilus parasuis is a member of the family Pasteurellaceae and a major causative agent of Glässer’s disease. This bacterium is normally a benign swine commensal but may become a deadly pathogen upon penetration into multiple tissues, contributing to severe lesions in swine. We have established a successive natural transformation-based markerless mutation system in this species. However, the two-step mutation system requires screening of natural competent cells, and cannot delete genes which regulate natural competence per se. In this study, we successfully obtained streptomycin-resistant derivatives from H. parasuis wild type strain SC1401 by using ethyl methane sulfonate (EMS, CH3SO2OC2H5. Upon sequencing and site-directed mutations, we uncovered that the EMS-induced point mutation in rpsL at codon 43rd (AAA → AGA; K43R or at 88th (AAA → AGA; K88R confers a much higher streptomycin resistance than clinical isolates. We have applied the streptomycin resistance marker as a positive selection marker to perform homologous recombination through conjugation and successfully generated a double unmarked in-frame targeted mutant 1401D88△tfox△arcA. Combined with a natural transformation-based knockout system and this genetic technique, multiple deletion mutants or attenuated strains of H. parasuis can be easily constructed. Moreover, the mutant genetic marker rpsL and streptomycin resistant phenotypes can serve as an effective tool to select naturally competent strains, and to verify natural transformation quantitatively.

  12. Biochemical studies with bi-resistant mutants (ethambutol plus streptomycin and isoniazid plus streptomycin) of Mycobacterium smegmatis ATCC 607

    International Nuclear Information System (INIS)

    Kanwar, Kavita; Khuller, G.K.

    1989-01-01

    Biochemical characteristics of bi-resistant mutants (resistant to ethambutol plus streptomycin or isoniazid plus streptomycin) of mycobacteria isolated by replica plating from Mycobacterium smegmatis ATCC were compared with those of the drug-susceptible strains. Reduced incorporation of ( 14 C)uracil, ( 3 H)lysine and ( 14 C)acetate into RNA, protein and phospholipids respectively was seen in the resistant mutants. Total phospholipids were enhanced in ethambutol plus streptomycin resistant mutant and decreased in ioniazid plus streptomycin resistant mutant. There were similar changes in levels of individual phospholipids. The resistant mutants revealed an accumulation of phospholipids in the cell wall, and a marked decrease of phospholipids in the cell memebrane in comparison to the susceptible strain. Several qualitative alterations in the polypeptide profile (with respect to number and molecular weight) of the crude protein extract and of different subcellular compartments were seen in the resistant mutants. (author). 35 refs., 3 tabs

  13. Transformability of streptomycin-resistant group H streptococci.

    Science.gov (United States)

    Perry, D

    1968-01-01

    Several resistant mutants of a transformable group H streptococcus, strain Challis, were isolated from media containing high concentrations of streptomycin. Mutants SR5a and SR5 exhibited high and low transformability, respectively, when exposed to deoxyribonucleic acid (DNA) from a novobiocin-resistant Challis strain. With similar exposure, mutant SR30 exhibited loss of transformability. The mutants further differed from the parent strain in time of appearance of optimal competence, and, in the case of SR5 and SR30, total growth was somewhat less than that of the parent. The rapidity with which transformants appeared upon initial exposure to DNA was approximately the same in the mutants and the parent strain. The decrease or loss of transformability of mutants SR5 and SR30 was found to be due to an alteration in capacity to take up DNA. Mutant SR5a (highly transformable) was further differentiated from mutants SR5 and SR30 in that it was somewhat more sensitive to high concentrations of streptomycin. Transformants obtained by treating strain Challis with the three types of mutant DNA, on the other hand, exhibited similar degrees of resistance to increasing concentrations of streptomycin. The additional decrease in transforming ability of mutant SR5a and the loss of transforming ability of mutant SR5 after a second exposure to streptomycin may indicate a stepwise process in the change from transformability to nontransformability. Although streptomycin resistance may not be directly related to inability to transform, results indicate that streptomycin greatly increases the chances of selecting these mutants and also can be of value in serving as a marker in studies of this nature.

  14. 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...

  15. Whole-genome sequencing reveals the mechanisms for evolution of streptomycin resistance in Lactobacillus plantarum.

    Science.gov (United States)

    Zhang, Fuxin; Gao, Jiayuan; Wang, Bini; Huo, Dongxue; Wang, Zhaoxia; Zhang, Jiachao; Shao, Yuyu

    2018-04-01

    In this research, we investigated the evolution of streptomycin resistance in Lactobacillus plantarum ATCC14917, which was passaged in medium containing a gradually increasing concentration of streptomycin. After 25 d, the minimum inhibitory concentration (MIC) of L. plantarum ATCC14917 had reached 131,072 µg/mL, which was 8,192-fold higher than the MIC of the original parent isolate. The highly resistant L. plantarum ATCC14917 isolate was then passaged in antibiotic-free medium to determine the stability of resistance. The MIC value of the L. plantarum ATCC14917 isolate decreased to 2,048 µg/mL after 35 d but remained constant thereafter, indicating that resistance was irreversible even in the absence of selection pressure. Whole-genome sequencing of parent isolates, control isolates, and isolates following passage was used to study the resistance mechanism of L. plantarum ATCC14917 to streptomycin and adaptation in the presence and absence of selection pressure. Five mutated genes (single nucleotide polymorphisms and structural variants) were verified in highly resistant L. plantarum ATCC14917 isolates, which were related to ribosomal protein S12, LPXTG-motif cell wall anchor domain protein, LrgA family protein, Ser/Thr phosphatase family protein, and a hypothetical protein that may correlate with resistance to streptomycin. After passage in streptomycin-free medium, only the mutant gene encoding ribosomal protein S12 remained; the other 4 mutant genes had reverted to the wild type as found in the parent isolate. Although the MIC value of L. plantarum ATCC14917 was reduced in the absence of selection pressure, it remained 128-fold higher than the MIC value of the parent isolate, indicating that ribosomal protein S12 may play an important role in streptomycin resistance. Using the mobile elements database, we demonstrated that streptomycin resistance-related genes in L. plantarum ATCC14917 were not located on mobile elements. This research offers a way of

  16. Enhanced antibiotic multi-resistance in nasal and faecal bacteria after agricultural use of streptomycin.

    Science.gov (United States)

    Scherer, Alexandre; Vogt, Hans-Rudolf; Vilei, Edy M; Frey, Joachim; Perreten, Vincent

    2013-01-01

    Streptomycin is used in arboriculture to control fire blight. Using sheep as a model, multidrug-resistant bacteria in mammals were found to be selected after the intentional release of streptomycin into the environment. Escherichia coli and Staphylococcus spp. were isolated from the faeces and nasal cavities, respectively, of sheep grazing on a field sprayed with streptomycin at concentrations used in orchards (test group) and on a field without streptomycin (control group). Before the application of streptomycin, the percentage of streptomycin-resistant E. coli isolates in faeces was 15.8% in the control group and 14.7% in the test group. After the application of streptomycin, the overall number of streptomycin-resistant E. coli isolates was significantly higher in the test group (39.9%) than in the control group (22.3%). Streptomycin-resistant Staphylococcus isolates were only detected after the application of streptomycin. Streptomycin resistance was frequently associated with resistance to sulfamethoxazole, ampicillin, tetracycline and chloramphenicol and less frequently to cefotaxime in E. coli, and to tetracycline, fusidic acid and tiamulin in Staphylococcus spp. This study shows that the application of low concentrations of streptomycin on grass, as occurs during the spraying of orchards, selects for multidrug-resistant nasal and enteric bacterial flora, including extended-spectrum beta-lactamase-producing E. coli. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  17. Ribosome slowed by mutation to streptomycin resistance. [Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Galas, D.J.; Branscomb, E.W.

    1976-08-12

    The effect of mutation to streptomycin resistance on the speed of polypeptide elongation in Escherichia coli was investigated. Translation speed was determined by measuring the time required for the first newly synthesized ..beta..-galactosidase molecules to appear after induction of the lactose operon. The results showed that ribosome speed is not a fixed parameter inherent to the protein synthetic apparatus, but a variable determined by the kinetics of translation and ultimately by the structure of the ribosome. (HLW)

  18. Detection of streptomycin resistance in Mycobacterium tuberculosis clinical isolates from China as determined by denaturing HPLC analysis and DNA sequencing.

    Science.gov (United States)

    Shi, Ruiru; Zhang, Jianyuan; Li, Chuanyou; Kazumi, Yuko; Sugawara, Isamu

    2007-01-01

    China is regarded by the World Health Organization as a major hot-spot region for Mycobacterium tuberculosis infection. Streptomycin has been deployed in China for over 50 years and is still widely used for tuberculosis treatment. We have developed a denaturing HPLC (DHPLC) method for detecting various gene mutations conferring drug resistance in M. tuberculosis. The present study focused on rpsL and rrs mutation analysis. Two hundred and fifteen M. tuberculosis clinical isolates (115 proved to be streptomycin-resistant and 100 susceptible by a routine proportional method) from China were tested to determine the streptomycin minimal inhibitory concentration (MIC), and subjected to DHPLC and concurrent DNA sequencing to determine rpsL and rrs mutations. The results showed that 85.2% (98/115) of streptomycin-resistant isolates harbored rpsL or rrs mutation, while rpsL mutation (76.5%, 88/115) dominated. MIC of 98 mutated isolates revealed no close correlation between mutation types and levels of streptomycin resistance. No mutation was found in any of the susceptible isolates. The DHPLC results were completely consistent with those of sequencing. The DHPLC method devised in this study can be regarded as a useful and powerful tool for detection of streptomycin resistance. This is the first report to describe DHPLC analysis of mutations in the rpsL and rrs genes of M. tuberculosis in a large number of clinical isolates.

  19. Culture-independent detection of "TM7" bacteria in a streptomycin-resistant acidophilic nitrifying process

    Science.gov (United States)

    Kurogi, T.; Linh, N. T. T.; Kuroki, T.; Yamada, T.; Hiraishi, A.

    2014-02-01

    Nitrification in biological wastewater treatment processes has been believed for long time to take place under neutral conditions and is inhibited under acidic conditions. However, we previously constructed acidophilic nitrifying sequencing-batch reactors (ANSBRs) being capable of nitrification at resistance to streptomycin at the ribosome level, this study was undertaken to construct streptomycin-resistant acidophilic nitrifying (SRAN) reactors and to demonstrate whether TM7 bacteria are abundant in these reactors. The SRAN reactors were constructed by seeding with nitrifying sludge from an ANSBR and cultivating with ammonium-containing mineral medium (pH 4.0), to which streptomycin at a concentration of 10, 30 and 50 mg L-1 was added. In all reactors, the pH varied between 2.7 and 4.0, and ammonium was completely converted to nitrate in every batch cycle. PCR-aided denaturing gradient gel electrophoresis (DGGE) targeting 16S rRNA genes revealed that some major clones assigned to TM7 bacteria and Gammaproteobacteria were constantly present during the overall period of operation. Fluorescence in situ hybridization (FISH) with specific oligonucleotide probes also showed that TM7 bacteria predominated in all SRAN reactors, accounting for 58% of the total bacterial population on average. Although the biological significance of the TM7 bacteria in the SRAN reactors are unknown, our results suggest that these bacteria are possibly streptomycin-resistant and play some important roles in the acidophilic nitrifying process.

  20. Enhanced antibiotic multi-resistance in nasal and faecal bacteria after agricultural use of streptomycin

    OpenAIRE

    Scherer, Alexandre; Vogt, Hans-Rudolf; Vilei, Edy M; Frey, Joachim; Perreten, Vincent

    2012-01-01

    Streptomycin is used in arboriculture to control fire blight. Using sheep as a model, multidrug-resistant bacteria in mammals were found to be selected after the intentional release of streptomycin into the environment. Escherichia coli and Staphylococcus spp. were isolated from the faeces and nasal cavities, respectively, of sheep grazing on a field sprayed with streptomycin at concentrations used in orchards (test group) and on a field without streptomycin (control group). Before the applic...

  1. Characterization of Streptomycin Resistance in Isolates of Erwinia amylovora in California.

    Science.gov (United States)

    Förster, Helga; McGhee, Gayle C; Sundin, George W; Adaskaveg, James E

    2015-10-01

    In surveys from 2006 to 2014, streptomycin resistance in Erwinia amylovora from pear-growing areas in California declined from very high incidence in 2006 and 2007 to very low incidence in 2013 and 2014. The majority of resistant strains were designated as moderately resistant-low (MR-L), and were almost exclusively found in Sacramento County, whereas highly resistant (HR) strains were only recovered in Sutter-Yuba and San Joaquin counties. Resistance of HR strains was associated with a mutation in codon 43 of the chromosomal rpsL gene that results in a change from lysine to arginine, the same mutation that was originally reported for resistant strains from California in the mid-1970s. MR-L strains were found to harbor the strA-strB streptomycin resistance genes on transposon Tn5393a. This transposon lacks insertion sequence IS1133 that provides a promoter for efficient expression of strA-strB, resulting in lower minimum inhibitory concentrations of MR-L strains compared with those from other locations that harbor strA-strB on Tn5393::IS1133. In contrast to previously described plasmid-mediated resistance where Tn5393 is inserted in pEa34, or pEA29, Tn5393a in MR-L strains was located on plasmid pEU30. This plasmid was first described in E. amylovora from the western United States but was not associated with streptomycin resistance determinants previously. We hypothesize that Tn5393a was introduced into an E. amylovora strain carrying pEU30 and transposed into that plasmid. This hypothesis was supported by clustered regularly interspaced short palindromic repeat (CRISPR) sequence analysis that showed that two MR-L strains share the same CRISPR1 pattern as a streptomycin-sensitive strain. With current low resistance levels in California growing regions, streptomycin could be successfully used again, but applications per season should be limited and the antibiotic should be mixed and rotated with different modes of action.

  2. rrs and rpsL mutations in streptomycin-resistant isolates of Mycobacterium tuberculosis from Mexico.

    Science.gov (United States)

    Cuevas-Córdoba, Betzaida; Cuellar-Sánchez, Aremy; Pasissi-Crivelli, Aurora; Santana-Álvarez, Carlos Armando; Hernández-Illezcas, Javier; Zenteno-Cuevas, Roberto

    2013-02-01

    Mutations in rpsL and rrs genes are associated with resistance to streptomycin in tuberculosis, but important geographical variation exists in these mutations. The goal of this study was to characterize these mutations in isolates of streptomycin-resistant mycobacteria originating from southeast Mexico. Mycobacteria were isolated from patients with suspected drug-resistant tuberculosis. Susceptibility tests were carried out using the fluorometric method, and rrs and rpsL DNA sequencing was performed by capillary electrophoresis. Some 136 drug-resistant isolates were recovered, of which 91(67%) exhibited resistance to streptomycin. Mutations in rpsL were observed in 18 isolates (19%) in codons 43 (A→G, K/R, n = 12) and 88 (A→G, K/R, n = 4; A→C, K/Q, n = 2). Mutations in rrs were observed in 26 isolates (28%). These were at nucleotides 513 (A→C, n = 8) and 516 (C→T, n = 6), and six novel mutations at nucleotides 483 (A→T, n = 2), 485 (A→G, n = 2), 496 (G→A, n = 2), 795 (C→T, n = 6), 870 (C→T, n = 3), and 907 (A→C, n = 3), with some isolates showing more than one mutation. Finally, 47 (52%) of the isolates showed no mutation. The variety and presence or absence of the mutations found suggest the circulation of an important diversity of strains and the existence of additional mechanisms contributing to streptomycin resistance in the region. Copyright © 2012. Published by Elsevier B.V.

  3. Transcription and translation in a pleiotropic streptomycin-resistant mutant of Escherichia coli.

    Science.gov (United States)

    Dennis, P P

    1979-01-01

    The role of the ribosomal protein S12 (streptomycin protein) in ribosome function and in other metabolic processes in the cell has been investigated. A spontaneous streptomycin-resistant strain of Escherichia coli (SM3) carrying a mutation in the rpsL gene is deficient in its ability to induce the synthesis of the enzyme bets-galactosidase. It was demonstrated that the reduced rate of enzyme synthesis results from deficiencies in both the transcription of the lactose operon and translation of the lactose operon mRNA. The transcription deficiency was in part due to increased catabolite repression and could therefore be partially suppressed by the addition of cyclic AMP. Streptomycin also appeared to partially suppress catabolite repression. In the SM3 mutant strain, the translation of the lactose operon mRNA was only about 60% as efficient as in the parental control, and addition of streptomycin did not alter the translation efficiency. In contrast, both transcription and translation of ribosomal protein mRNA were equally efficient in the two strains. These observations imply that mutational alterations in the ribosomal protein S12 either directly or indirectly alter (i) the extent of catabolite repression, (ii) the efficiency of transcription of the lactose operon even in the absence of catabolite repression, and (iii) the efficiency of translation of some but not all mRNA species in the cell.

  4. Protoplast-derived streptomycin resistant plants of the forage legume Onobrychis viciifolia Scop. (sainfoin).

    Science.gov (United States)

    Hamill, J D; Ahuja, P S; Davey, M R; Cocking, E C

    1986-12-01

    Approximately 10(6) protoplast-derived cell colonies of sainfoin were stressed with streptomycin and two resistant colonies were recovered. Plants regenerated from these colonies could be recallused on streptomycin-containing medium three years after growth in the absence of the antibiotic.Ultrastructural studies showed cells of resistant callus grown in the presence of streptomycin to contain chloroplasts with internal thykaloids and grana. Such mutant plants should be useful in designing biochemical selection schemes to recover somatic hybrids and cybrids.

  5. The ancient small mobilizable plasmid pALWED1.8 harboring a new variant of the non-cassette streptomycin/spectinomycin resistance gene aadA27.

    Science.gov (United States)

    Kurakov, Anton; Mindlin, Sofia; Beletsky, Alexey; Shcherbatova, Natalya; Rakitin, Andrey; Ermakova, Aleksandra; Mardanov, Andrey; Petrova, Mayya

    2016-01-01

    The small mobilizable plasmid pALWED1.8 containing a novel variant of the streptomycin/spectinomycin resistance gene aadA27 was isolated from the permafrost strains of Acinetobacter lwoffii. The 4135bp plasmid carries mobА and mobC genes that mediate its mobilization by conjugative plasmids. The nucleotide sequences of mobА and mobC are similar to those of mobilization genes of the modern plasmid pRAY* and its variants, which contain aadB gene, and are widespread among the pathogenic strains of Acinetobacter baumannii. Almost identical pALWED1.8 variants were detected in modern environmental Аcinetobacter strains. A highly similar plasmid was revealed in a strain of Acinetobacter parvus isolated from mouse intestine. Furthermore, we discovered six previously unidentified variants of plasmids related to pALWED1.8 and pRAY* in public databases. In contrast to most known variants of aadA which are cassette genes associated with integrons, the aadA27 variant harbored by pALWED1.8 is a non-cassette, autonomously transcribed gene. Non-cassette aadA genes with 96% sequence identity to aadA27 were detected in the chromosomes of Acinetobacter gyllenbergii and several uncharacterized strains of Аcinetobacter sp. Moreover, we revealed that the autonomous aadA-like genes are present in the chromosomes of many gram-positive and gram-negative bacteria. The phylogenetic analysis of amino acid sequences of all identified AadA proteins showed the following: (i) cassette aadA genes form a separate monophyletic group and mainly reside on plasmids and (ii) chromosomal non-cassette aadA genes are extremely diverse and can be inherited both vertical and via horizontal gene transfer. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Identification of mutations conferring streptomycin resistance in multidrug-resistant tuberculosis of China.

    Science.gov (United States)

    Zhao, Li-Li; Liu, Hai-Can; Sun, Qing; Xiao, Tong-Yang; Zhao, Xiu-Qin; Li, Gui-Lian; Zeng, Chun-Yan; Wan, Kang-Lin

    2015-10-01

    We investigated the spectrum and frequency of mutations in rpsL, rrs, and gidB among 140 multidrug-resistant tuberculosis (MDR-TB) clinical isolates from China. The association between mutations and different genotypes was also analyzed. Our data revealed that 65.7% of MDR-TB were resistant to streptomycin (STR), and 90.2% of STR-resistant isolates were Beijing strains. STR resistance was correlated with Beijing family (P=0.00). Compared with phenotypic data, detection of mutations for the combination of these 3 genes exhibited 94.6% sensitivity, 91.7% specificity, and 93.6% accuracy. The most common mutations in STR-resistant isolates were rpsL128, 262, and rrs514, of which rpsL128 showed association with Beijing lineage (P=0.00). A combination of these 3 mutations can serve as the reliable predictors for STR resistance, showing the sensitivity, specificity, and accuracy of 85.9%, 97.9%, and 90.0%, respectively. Furthermore, gidBA276C, not A615G, was Beijing lineage specific. These findings are useful to develop rapid molecular diagnostic methods for STR resistance in China. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Sublethal streptomycin concentrations and lytic bacteriophage together promote resistance evolution.

    Science.gov (United States)

    Cairns, Johannes; Becks, Lutz; Jalasvuori, Matti; Hiltunen, Teppo

    2017-01-19

    Sub-minimum inhibiting concentrations (sub-MICs) of antibiotics frequently occur in natural environments owing to wide-spread antibiotic leakage by human action. Even though the concentrations are very low, these sub-MICs have recently been shown to alter bacterial populations by selecting for antibiotic resistance and increasing the rate of adaptive evolution. However, studies are lacking on how these effects reverberate into key ecological interactions, such as bacteria-phage interactions. Previously, co-selection of bacteria by phages and antibiotic concentrations exceeding MICs has been hypothesized to decrease the rate of resistance evolution because of fitness costs associated with resistance mutations. By contrast, here we show that sub-MICs of the antibiotic streptomycin (Sm) increased the rate of phage resistance evolution, as well as causing extinction of the phage. Notably, Sm and the phage in combination also enhanced the evolution of Sm resistance compared with Sm alone. These observations demonstrate the potential of sub-MICs of antibiotics to impact key ecological interactions in microbial communities with evolutionary outcomes that can radically differ from those associated with high concentrations. Our findings also contribute to the understanding of ecological and evolutionary factors essential for the management of the antibiotic resistance problem.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'. © 2016 The Author(s).

  8. Screening for streptomycin resistance conferring mutations in Mycobacterium tuberculosis isolates from Iran.

    Science.gov (United States)

    Rezaei, Faranak; Haeili, Mehri; Imani Fooladi, Abbasali; Azari Garmjan, Gholam Ali; Feizabadi, Mohammad Mehdi

    2017-02-01

    Point mutations in the rpsL and rrs genes can lead to development of streptomycin (STR) resistance in Mycobacterium tuberculosis. The aims of this study were to determine the frequency of mutations in STR resistant M. tuberculosis isolates in Iran and to analyze the possible relationship between bacterial genotype and STR resistance. Twenty-three M. tuberculosis samples comprising 9 multidrug-resistant (MDR) and 14 non-MDR isolates, recovered from TB patients in four regions: Tehran (n = 14), Isfahan (n = 2), Zahedan (n = 2), and Khorasan (n = 5), were analysed. Mutational profiling was performed by sequencing of the rrs and rpsL genes and spoligotyping method was used for genotyping. Nineteen isolates were resistant to STR, among them 7 exhibited mutations in the rpsL gene and 7 had mutations in the rrs gene. The remaining 5 STR resistant as well as all susceptible isolates lacked any mutation in both genes. Beijing genotype was associated with both MDR and STR resistance in which all mutations occurred at codon 43 of the rpsL gene. There was an association between mutations in the rpsL and rrs genes and STR resistance. We also found a correlation between Beijing genotype and STR resistance.

  9. [A rapid screening program on the resistance to streptomycin and ethambutol in Mycobacterium tuberculosis isolates by PCR melting curve analysis].

    Science.gov (United States)

    Wang, Feng; Hu, Si-yu; Gui, Jing; Cui, Yun-yong; Liu, Xiao-li; Li, Qing-ge

    2012-05-01

    To evaluate the effects of PCR melting curve analysis assay on a rapid screening program regarding the resistance of Mycobacterium tuberculosis (MTB) clinical isolates to streptomycin and ethambutol. A total of 331 clinical isolates of MTB had been collected since 2007-2009 in Shenzhen. Mutations at codon 306, 378-380, 406 and 497 of embB gene, codon 43, 88 of rpsL gene, and 513-517, 905-908 region of rrs gene were detected by PCR melting curve analysis. Results were compared with that of conventional drug susceptibility test. Compared to drug susceptibility test, sensitivity, specificity and accuracy for streptomycin resistance were 78.6%, 90.1% and 86.7%, respectively while 83.0%, 93.3% and 91.8%, respectively for ethambutol resistance detected by PCR melting curve analysis. PCR melting curve method was in good agreement with drug susceptibility test. PCR melting curve analysis on genetic regions associated with resistance to streptomycin and ethambutol seemed to be a rapid, specific and closed-tube method so it could be used for detection of streptomycin and ethambutol resistance in MTB.

  10. The 79,370-bp conjugative plasmid pB4 consists of an IncP-1beta backbone loaded with a chromate resistance transposon, the strA-strB streptomycin resistance gene pair, the oxacillinase gene bla(NPS-1), and a tripartite antibiotic efflux system of the resistance-nodulation-division family.

    Science.gov (United States)

    Tauch, A; Schlüter, A; Bischoff, N; Goesmann, A; Meyer, F; Pühler, A

    2003-02-01

    Plasmid pB4 is a conjugative antibiotic resistance plasmid, originally isolated from a microbial community growing in activated sludge, by means of an exogenous isolation method with Pseudomonas sp. B13 as recipient. We have determined the complete nucleotide sequence of pB4. The plasmid is 79,370 bp long and contains at least 81 complete coding regions. A suite of coding regions predicted to be involved in plasmid replication, plasmid maintenance, and conjugative transfer revealed significant similarity to the IncP-1beta backbone of R751. Four resistance gene regions comprising mobile genetic elements are inserted in the IncP-1beta backbone of pB4. The modular 'gene load' of pB4 includes (1) the novel transposon Tn 5719 containing genes characteristic of chromate resistance determinants, (2) the transposon Tn 5393c carrying the widespread streptomycin resistance gene pair strA-strB, (3) the beta-lactam antibiotic resistance gene bla(NPS-1) flanked by highly conserved sequences characteristic of integrons, and (4) a tripartite antibiotic resistance determinant comprising an efflux protein of the resistance-nodulation-division (RND) family, a periplasmic membrane fusion protein (MFP), and an outer membrane factor (OMF). The components of the RND-MFP-OMF efflux system showed the highest similarity to the products of the mexCD-oprJ determinant from the Pseudomonas aeruginosa chromosome. Functional analysis of the cloned resistance region from pB4 in Pseudomonas sp. B13 indicated that the RND-MFP-OMF efflux system conferred high-level resistance to erythromycin and roxithromycin resistance on the host strain. This is the first example of an RND-MFP-OMF-type antibiotic resistance determinant to be found in a plasmid genome. The global genetic organization of pB4 implies that its gene load might be disseminated between bacteria in different habitats by the combined action of the conjugation apparatus and the mobility of its component elements.

  11. A mutation in the 530 loop of Escherichia coli 16S ribosomal RNA causes resistance to streptomycin.

    OpenAIRE

    Melançon, P; Lemieux, C; Brakier-Gingras, L

    1988-01-01

    Oligonucleotide-directed mutagenesis was used to introduce an A to C transversion at position 523 in the 16S ribosomal RNA gene of Escherichia coli rrnB operon cloned in plasmid pKK3535. E. coli cells transformed with the mutated plasmid were resistant to streptomycin. The mutated ribosomes isolated from these cells were not stimulated by streptomycin to misread the message in a poly(U)-directed assay. They were also restrictive to the stimulation of misreading by other error-promoting relate...

  12. Mutations in gidB confer low-level streptomycin resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Wong, Sharon Y; Lee, Jong Seok; Kwak, Hyun Kyung; Via, Laura E; Boshoff, Helena I M; Barry, Clifton E

    2011-06-01

    The global threat posed by drug-resistant strains of Mycobacterium tuberculosis demands a greater understanding of the genetic basis and molecular mechanisms that govern how such strains develop resistance against various antituberculous drugs. In this report, we examine a new genetic basis for resistance to one of the oldest and most widely used second-line drugs employed in tuberculosis therapy, streptomycin (SM). This marker for SM resistance was first discovered on the basis of genomic data obtained from drug-resistant M. tuberculosis strains collected in Japan, wherein an association was observed between SM resistance and a mutation in gidB, a putative 16S rRNA methyltransferase. By evaluating an isogenic ΔgidB mutant strain constructed from strain H37Rv, we demonstrate the causal role of gidB in conferring a low-level SM-resistant phenotype in M. tuberculosis with a 16-fold increase in the MIC over the parent strain. Among clinical isolates, the modest increase in SM resistance conferred by a gidB mutation leads to an MIC distribution of gidB mutation-containing strains that spans the recommended SM breakpoint concentration currently used in drug susceptibility testing protocols. As such, some gidB mutation-containing isolates are found to be SM sensitive, while others are SM resistant. On the basis of a pharmacodynamic analysis and Monte Carlo simulation, those isolates that are found to be SM sensitive should still respond favorably to SM treatment, while nearly half of those found to be SM resistant will likely respond poorly. This report provides the first microbiological evidence for the contribution of gidB in streptomycin resistance and examines the clinical implications of mutations in the gidB gene.

  13. Mutations in gidB Confer Low-Level Streptomycin Resistance in Mycobacterium tuberculosis▿†

    Science.gov (United States)

    Wong, Sharon Y.; Lee, Jong Seok; Kwak, Hyun Kyung; Via, Laura E.; Boshoff, Helena I. M.; Barry, Clifton E.

    2011-01-01

    The global threat posed by drug-resistant strains of Mycobacterium tuberculosis demands a greater understanding of the genetic basis and molecular mechanisms that govern how such strains develop resistance against various antituberculous drugs. In this report, we examine a new genetic basis for resistance to one of the oldest and most widely used second-line drugs employed in tuberculosis therapy, streptomycin (SM). This marker for SM resistance was first discovered on the basis of genomic data obtained from drug-resistant M. tuberculosis strains collected in Japan, wherein an association was observed between SM resistance and a mutation in gidB, a putative 16S rRNA methyltransferase. By evaluating an isogenic ΔgidB mutant strain constructed from strain H37Rv, we demonstrate the causal role of gidB in conferring a low-level SM-resistant phenotype in M. tuberculosis with a 16-fold increase in the MIC over the parent strain. Among clinical isolates, the modest increase in SM resistance conferred by a gidB mutation leads to an MIC distribution of gidB mutation-containing strains that spans the recommended SM breakpoint concentration currently used in drug susceptibility testing protocols. As such, some gidB mutation-containing isolates are found to be SM sensitive, while others are SM resistant. On the basis of a pharmacodynamic analysis and Monte Carlo simulation, those isolates that are found to be SM sensitive should still respond favorably to SM treatment, while nearly half of those found to be SM resistant will likely respond poorly. This report provides the first microbiological evidence for the contribution of gidB in streptomycin resistance and examines the clinical implications of mutations in the gidB gene. PMID:21444711

  14. Association of streptomycin resistance mutations with level of drug resistance and Mycobacterium tuberculosis genotypes.

    Science.gov (United States)

    Nhu, N T Q; Lan, N T N; Phuong, N T N; Chau, N van V; Farrar, J; Caws, M

    2012-04-01

    To determine 1) the relationship between specific streptomycin (SM) resistance mutations and the minimum inhibitory concentration (MIC), and 2) whether these mutations are preferentially associated with the Beijing genotype in Viet Nam. A total of 131 consecutive Mycobacterium tuberculosis isolates resistant to either isoniazid (INH) or rifampicin (RMP), collected previously, were tested for SM resistance, spoligotyped and sequenced in the rpsL, rrs and gidB genes. The MIC for 50 mutants was also determined. Overall, 116/131 isolates were SM-resistant. The three most frequently occurring mutation sites in rpsL and rrs were at codon 43 of rpsL (72/116, 62.1%), rpsL88 (22/116, 18.9%) and rrs514 (8/116, 6.9%). Mutations in the rrs910 region were found in two isolates (1.7%), and three isolates had mutations in both rpsL and rrs (2.6%). gidB mutations were found in both resistant and susceptible strains. Among SM-resistant isolates resistant to INH/RMP, the Beijing genotype was strongly associated with rpsL43 mutation (aOR 23.6, 95%CI 2.9-193.4, P = 0.002). The median MIC for each mutation was as follows: rpsL43 = 256 μg/ml, rpsL88 = 16 μg/ml, 515 loop = 4 μg/ml, 910 region = 8 μg/ml, and double mutation = 256 μg/ml. We found a strong association between rpsL43 and high drug resistance levels, with all rpsL43 mutants having an MIC >256 μg/ml (P < 0.001).

  15. Loss of a conserved 7-methylguanosine modification in 16S rRNA confers low-level streptomycin resistance in bacteria.

    Science.gov (United States)

    Okamoto, Susumu; Tamaru, Aki; Nakajima, Chie; Nishimura, Kenji; Tanaka, Yukinori; Tokuyama, Shinji; Suzuki, Yasuhiko; Ochi, Kozo

    2007-02-01

    Streptomycin has been an important drug for the treatment of tuberculosis since its discovery in 1944. But numerous strains of Mycobacterium tuberculosis, the bacterial pathogen that causes tuberculosis, are now streptomycin resistant. Although such resistance is often mediated by mutations within rrs, a 16S rRNA gene or rpsL, which encodes the ribosomal protein S12, these mutations are found in a limited proportion of clinically isolated streptomycin-resistant M. tuberculosis strains. Here we have succeeded in identifying a mutation that confers low-level streptomycin resistance to bacteria, including M. tuberculosis. We found that mutations within the gene gidB confer low-level streptomycin resistance and are an important cause of resistance found in 33% of resistant M. tuberculosis isolates. We further clarified that the gidB gene encodes a conserved 7-methylguanosine (m(7)G) methyltransferase specific for the 16S rRNA, apparently at position G527 located in the so-called 530 loop. Thus, we have identified gidB as a new streptomycin-resistance locus and uncovered a resistance mechanism that is mediated by loss of a conserved m(7)G modification in 16S rRNA. The clinical significance of M. tuberculosis gidB mutation also is noteworthy, as gidB mutations emerge spontaneously at a high frequency of 10(-6) and, once emerged, result in vigorous emergence of high-level streptomycin-resistant mutants at a frequency more than 2000 times greater than that seen in wild-type strains. Further studies on the precise function of GidB may provide a basis for developing strategies to suppress pathogenic bacteria, including M. tuberculosis.

  16. A mutation in the 530 loop of Escherichia coli 16S ribosomal RNA causes resistance to streptomycin.

    Science.gov (United States)

    Melançon, P; Lemieux, C; Brakier-Gingras, L

    1988-01-01

    Oligonucleotide-directed mutagenesis was used to introduce an A to C transversion at position 523 in the 16S ribosomal RNA gene of Escherichia coli rrnB operon cloned in plasmid pKK3535. E. coli cells transformed with the mutated plasmid were resistant to streptomycin. The mutated ribosomes isolated from these cells were not stimulated by streptomycin to misread the message in a poly(U)-directed assay. They were also restrictive to the stimulation of misreading by other error-promoting related aminoglycoside antibiotics such as neomycin, kanamycin or gentamicin, which do not compete for the streptomycin binding site. The 530 loop where the mutation in the 16S rRNA is located has been mapped at the external surface of the 30S subunit, and is therefore distal from the streptomycin binding site at the subunit interface. Our results support the conclusion that the mutation at position 523 in the 16S rRNA does not interfere with the binding of streptomycin, but prevents the drug from inducing conformational changes in the 530 loop which account for its miscoding effect. Since this effect primarily results from a perturbation of the translational proofreading control, our results also provide evidence that the 530 loop of the 16S rRNA is involved in this accuracy control. Images PMID:3054810

  17. Defective lysis of streptomycin-resistant escherichia coli cells infected with bacteriophage f2.

    OpenAIRE

    De Mars Cody, J; Conway, T W

    1981-01-01

    A lysis defect was found to account for the failure of a streptomycin-resistant strain of Escherichia coli to form plaques when infected with the male-specific bacteriophage f2. The lysis defect was associated with the mutation to streptomycin resistance. Large amounts of apparently normal bacteriophage accumulated in these cells. Cell-free extracts from both the parental and mutant strains synthesized a potential lysis protein in considerable amounts in response to formaldehyde-treated f2 RN...

  18. Detection and Characterization of Streptomycin Resistance (strA-strB) in a Honeybee Gut Symbiont (Snodgrassella alvi) and the Associated Risk of Antibiotic Resistance Transfer.

    Science.gov (United States)

    Ludvigsen, Jane; Amdam, Gro V; Rudi, Knut; L'Abée-Lund, Trine M

    2018-03-08

    Use of antibiotics in medicine and farming contributes to increasing numbers of antibiotic-resistant bacteria in diverse environments. The ability of antibiotic resistance genes (ARG) to transfer between bacteria genera contributes to this spread. It is difficult to directly link antibiotic exposure to the spread of ARG in a natural environment where environmental settings and study populations cannot be fully controlled. We used managed honeybees in environments with contrasting streptomycin exposure (USA: high exposure, Norway: low exposure) and mapped the prevalence and spread of transferrable streptomycin resistance genes. We found a high prevalence of strA-strB genes in the USA compared to Norway with 17/90 and 1/90 positive samples, respectively (p resistance genes increases the risk of the spread to new environments as honeybees are moved to new pollination sites.

  19. Structural analysis of base substitutions in Thermus thermophilus 16S rRNA conferring streptomycin resistance.

    Science.gov (United States)

    Demirci, Hasan; Murphy, Frank V; Murphy, Eileen L; Connetti, Jacqueline L; Dahlberg, Albert E; Jogl, Gerwald; Gregory, Steven T

    2014-08-01

    Streptomycin is a bactericidal antibiotic that induces translational errors. It binds to the 30S ribosomal subunit, interacting with ribosomal protein S12 and with 16S rRNA through contacts with the phosphodiester backbone. To explore the structural basis for streptomycin resistance, we determined the X-ray crystal structures of 30S ribosomal subunits from six streptomycin-resistant mutants of Thermus thermophilus both in the apo form and in complex with streptomycin. Base substitutions at highly conserved residues in the central pseudoknot of 16S rRNA produce novel hydrogen-bonding and base-stacking interactions. These rearrangements in secondary structure produce only minor adjustments in the three-dimensional fold of the pseudoknot. These results illustrate how antibiotic resistance can occur as a result of small changes in binding site conformation. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  20. [Detection of streptomycin resistance in Mycobacterium tuberculosis clinical isolates by denaturing high-performance liquid chromatography and DNA sequencing].

    Science.gov (United States)

    Shi, Rui-ru; Zhang, Jian-yuan; Yuan, Xue-qin; Sun, Zhao-gang; Li, Chuan-you

    2008-05-27

    To determine the rpsL and rrs gene mutation in Mycobacterium tuberculosis (M. tuberculosis) and compare the consistency between the results of denaturing high-performance liquid chromatography (DHPLC) and those of DNA sequencing. The values of streptomycin minimum inhibitory concentration (MIC) against 215 M. tuberculosis clinical isolates, 115 being streptomycin-resistant and 100 being susceptible by a routine proportional method, were tested by DHPLC. DNA sequencing was conducted to detect the rpsL and rrs mutation. 98 of the 115 streptomycin-resistant isolates (85.2%) harbored rpsL and/or rrs mutation, 76.5% of which being rpsL mutation (88/115). There was no significant correlation between the MIC values and mutation types. No mutation was found in all the susceptible isolates. There was a complete consistency between the DHPLC results and those of DNA sequencing. DHPLC can be regarded as a useful and powerful tool to detect the streptomycin resistance detection in M. tuberculosis.

  1. Resistance to penicillin-streptomycin synergy among clinical isolates of viridans streptococci.

    Science.gov (United States)

    Farber, B F; Eliopoulos, G M; Ward, J I; Ruoff, K; Moellering, R C

    1983-01-01

    Viridans streptococci are thought to be highly susceptible to penicillin and streptomycin. We recently encountered a unique group of 15 isolates from South Africa epidemiologically related to the isolation of penicillin-resistant pneumococci. These organisms were highly resistant to penicillin (PCN) (minimal inhibitory concentration, 1 to 32 micrograms/ml) and streptomycin (SM) (minimal inhibitory concentration, greater than or equal to 2,000 micrograms/ml). Two additional organisms with high-level streptomycin resistance were identified when 168 clinical isolates from Boston were screened. Time-kill studies with four organisms resistant to high levels of SM demonstrated lack of synergy between PCN and SM but marked synergy between PCN and gentamicin. Adenylylating, acetylating, and phosphorylating activity could not be detected in three organisms studied, and novobiocin failed to cure the SM resistance. Protein synthesis by ribosomes isolated from these organisms was dramatically reduced in the presence of gentamicin but was relatively resistant to inhibition by SM. PMID:6559052

  2. Detection of streptomycin and quinolone resistance in Mycobacterium tuberculosis by a low-density DNA array.

    Science.gov (United States)

    Moure, Raquel; Tudó, Griselda; Medina, Rebeca; Vicente, Eva; Caldito, José María; Codina, Maria Gemma; Coll, Pere; Español, Montserrat; Gonzalez-Martin, Julian; Rey-Jurado, Emma; Salvadó, Margarita; Tórtola, Maria Teresa; Alcaide, Fernando

    2013-09-01

    In cases of multidrug-resistant tuberculosis, it is crucial to rule out resistance to second-line antituberculous (anti-TB) agents. In the present study, a low-cost low-density DNA array including four genetic regions (rrs 530 loop, rrs 1400, rpsL and gyrA) was designed for the rapid detection of the most important mutations related to anti-TB injectable drugs (mainly streptomycin) and fluoroquinolone resistance (LD-SQ array). A total of 108 streptomycin- and/or ofloxacin-resistant and 20 streptomycin- and ofloxacin-susceptible Mycobacterium tuberculosis clinical isolates were analysed with the array. The results obtained were compared with sequencing data and phenotypic susceptibility pattern. The LD-SQ array offered a good sensitivity compared to sequencing, especially among resistant strains: 92.5% (37/40) for streptomycin and 87.5% (7/8) for fluoroquinolones. Therefore, this array could be considered a good approach for the rapid detection of mutations related to streptomycin and fluoroquinolone resistance. On the other hand, there were discordant results in 16 resistant strains and six susceptible isolates, mostly concerning the gyrA region, in which the existence of polymorphisms next to informative positions might cause cross-hybridization. These discrepancies were caused by some technical limitations; consequently, the present array should be considered as a first-step prior to a forthcoming optimized version of the array. © 2013 Published by Elsevier Ltd.

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

    Science.gov (United States)

    Chudobova, Dagmar; Dostalova, Simona; Blazkova, Iva; Michalek, Petr; Ruttkay-Nedecky, Branislav; Sklenar, Matej; Nejdl, Lukas; Kudr, Jiri; Gumulec, Jaromir; Tmejova, Katerina; Konecna, Marie; Vaculovicova, Marketa; Hynek, David; Masarik, Michal; Kynicky, Jindrich; Kizek, Rene; Adam, Vojtech

    2014-01-01

    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. PMID:24651395

  4. Enhanced Survival of Rifampin- and Streptomycin-Resistant Escherichia coli Inside Macrophages.

    Science.gov (United States)

    Durão, Paulo; Gülereşi, Daniela; Proença, João; Gordo, Isabel

    2016-07-01

    The evolution of multiple-antibiotic-resistant bacteria is an increasing global problem. Even though mutations causing resistance usually incur a fitness cost in the absence of antibiotics, the magnitude of such costs varies across environments and genomic backgrounds. We studied how the combination of mutations that confer resistance to rifampin (Rif(r)) and streptomycin (Str(r)) affects the fitness of Escherichia coli when it interacts with cells from the immune system, i.e., macrophages (Mϕs). We found that 13 Rif(r) Str(r) doubly resistant genotypes, of the 16 tested, show a survival advantage inside Mϕs, indicating that double resistance can be highly beneficial in this environment. Our results suggest that there are multiple paths to acquire multiple-drug resistance in this context, i.e., if a clone carrying Rif(r) allele H526 or S531 acquires a second mutation conferring Str(r), the resulting double mutant has a high probability of showing increased survival inside Mϕs. On the other hand, we found two cases of sign epistasis between mutations, leading to a significant decrease in bacterial survival. Remarkably, infection of Mϕs with one of these combinations, K88R+H526Y, resulted in an altered pattern of gene expression in the infected Mϕs. This indicates that the fitness effects of resistance may depend on the pattern of gene expression of infected host cells. Notwithstanding the benefits of resistance found inside Mϕs, the Rif(r) Str(r) mutants have massive fitness costs when the bacteria divide outside Mϕs, indicating that the maintenance of double resistance may depend on the time spent within and outside phagocytic cells. Copyright © 2016 Durão et al.

  5. Analysis of isoniazid, streptomycin and ethambutol resistance in Mycobacterium tuberculosis isolates from Morocco.

    Science.gov (United States)

    Chaoui, Imane; Sabouni, Radia; Kourout, Moussa; Jordaan, Annemie M; Lahlou, Ouafae; Elouad, Rajae; Akrim, Mohammed; Victor, Thomas C; El Mzibri, Mohammed

    2009-05-01

    Drug-resistant tuberculosis is a major problem worldwide. Based on the knowledge of specific mutations occurring in Mycobacterium tuberculosis genome, drug resistance can be detected earlier. The aim of this study was to determine the prevalence of the most common mutations associated with resistance to Isoniazid (INH), Streptomycin (SM) and Ethambutol (EMB) in Mycobacterium tuberculosis isolates from Morocco in order to select target mutations to develop tests for rapid detection of drug-resistant Mycobacterium tuberculosis Moroccan isolates. A total of 199 M. tuberculosis isolates collected from the National Tuberculosis Reference Laboratory in Morocco were subject to katG, inhA, rrs, rpsL and emb mutation analysis by PCR probe-based assay. The genotypic results were then compared to drug susceptibility testing results for the corresponding drugs. Among 66 phenotypically INH resistant isolates, 80.3% (53/66) were found to be genotypically INH resistant from which 77.3% (51/66) and 3% (2/66) had respective mutations in katG315 and inhp-15 codons. Of the 58 phenotypically SM resistant isolates, genotypic SM resistance was confirmed in 17.2% (10/58) cases. Nucleotide mutations at codons 43 and 88 of rpsL gene and at codon 512 of rrs gene were found respectively in 12.1% (7/58); 1.7% (1/58) and 3.4% (2/58) of the phenotypically SM resistant Mycobacterium tuberculosis isolates. Finally, mutations at codon 306 of embB gene were identified in 42.3% (11/26) of Mycobacterium tuberculosis isolates phenotypically EMB resistant. This study showed that a large proportion of Mycobacterium tuberculosis resistant isolates from Morocco carry a large number of mutations in different codons (especially katG315, embB306 and rpsL43) of the corresponding genes associated with drug resistance. Thus, molecular analysis based on the identification of such mutations is useful but not fully sufficient to predict all drug resistance cases. Based on these results, rapid drug resistance

  6. Characterization of mutations in streptomycin-resistant Mycobacterium tuberculosis isolates in Sichuan, China and the association between Beijing-lineage and dual-mutation in gidB.

    Science.gov (United States)

    Sun, Honghu; Zhang, Congcong; Xiang, Ling; Pi, Rui; Guo, Zhen; Zheng, Chao; Li, Song; Zhao, Yuding; Tang, Ke; Luo, Mei; Rastogi, Nalin; Li, Yuqing; Sun, Qun

    2016-01-01

    Mutations in rpsL, rrs, and gidB are well linked to streptomycin (STR) resistance, some of which are suggested to be potentially associated with Mycobacterium tuberculosis genotypic lineages in certain geographic regions. In this study, we aimed to investigate the mutation characteristics of streptomycin resistance and the relationship between the polymorphism of drug-resistant genes and the lineage of M. tuberculosis isolates in Sichuan, China. A total of 227 M. tuberculosis clinical isolates, including 180 STR-resistant and 47 pan-susceptible isolates, were analyzed for presence of mutations in the rpsL, rrs and gidB loci. Mutation K43R in rpsL was strongly associated with high-level streptomycin resistance (P resistance (P resistance and Beijing genotype, however, in STR-resistant strains, Beijing genotype was significantly correlated with high-level STR resistance, as well as the rpsL mutation K43R (P streptomycin pressure. Notably, in all isolates of Beijing genotype, a dual mutation E92D (a276c) and A205A (a615g) in gidB was detected, suggesting a highly significant association between this dual mutation and Beijing genotype. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Screening for streptomycin resistance-conferring mutations in Mycobacterium tuberculosis clinical isolates from Poland.

    Science.gov (United States)

    Jagielski, Tomasz; Ignatowska, Helena; Bakuła, Zofia; Dziewit, Łukasz; Napiórkowska, Agnieszka; Augustynowicz-Kopeć, Ewa; Zwolska, Zofia; Bielecki, Jacek

    2014-01-01

    Currently, mutations in three genes, namely rrs, rpsL, and gidB, encoding 16S rRNA, ribosomal protein S12, and 16S rRNA-specific methyltransferase, respectively, are considered to be involved in conferring resistance to streptomycin (STR) in Mycobacterium tuberculosis. The aim of this study was to investigate the spectrum and frequency of these mutations in M. tuberculosis clinical isolates, both resistant and susceptible to STR. Sixty-four M. tuberculosis isolates recovered from as many TB patients from Poland in 2004 were included in the study. Within the sample were 50 multidrug-resistant (32 STR-resistant and 18 STR-susceptible) and 14 pan-susceptible isolates. Preliminary testing for STR resistance was performed with the 1% proportion method. The MICs of STR were determined by the Etest method. Mutation profiling was carried out by amplifying and sequencing the entire rrs, rpsL, and gidB genes. Non-synonymous mutations in either rrs or rpsL gene were detected in 23 (71.9%) of the STR-resistant and none of the STR-susceptible isolates. Mutations in the gidB gene were distributed among 12 (37.5%) STR-resistant and 13 (40.6%) STR-susceptible isolates. Four (12.5%) STR-resistant isolates were wild-type at all three loci examined. None of the rrs, rpsL or gidB mutations could be linked to low, intermediate or high level of STR resistance. In accordance with previous findings, the gidB 47T→G (L16R) mutation was associated with the Latin American-Mediterranean genotype family, whereas 276A→C (E92D) and 615A→G (A205A) mutations of the gidB gene were associated with the Beijing lineage. The study underlines the usefulness of rrs and rpsL mutations as molecular markers for STR resistance yet not indicative of its level. The gidB polymorphisms can serve as phylogenetic markers.

  8. Cross-resistance of Mycobacterium tuberculosis isolates among streptomycin, kanamycin and amikacin.

    Science.gov (United States)

    Sugawara, I; Zhang, J; Li, C

    2009-06-01

    Seventy-four streptomycin (SM)-resistant M. tuberculosis clinical isolates were subjected to cross-resistance drug testing against two major aminoglycosides, kanamycin (KM) and amikacin (AMK). Among them, 15 clinical isolates (20.3%) were resistant to both KM and AMK. Fifteen (80%) of 19 KM-resistant isolates were AMK-resistant. Fifteen SM, KM, and AMK resistant isolates harbored rrs mutation, but only two had rrs and rpsL double mutations. Low-level SM resistance was associated with rpsL mutation, whereas high-level SM resistance was linked to rrs mutation.

  9. Evaluation of gidB alterations responsible for streptomycin resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Verma, Jitender S; Gupta, Yash; Nair, Deepthi; Manzoor, Nikhat; Rautela, Rajinder S; Rai, Arvind; Katoch, Vishwa M

    2014-11-01

    To evaluate gidB alterations for possible impact on the cumulative mechanism underlying the acquisition of high-level streptomycin resistance in Mycobacterium tuberculosis. Fifty-two isolates with high streptomycin resistance and 23 isolates with low streptomycin resistance were sequenced for mutational analysis in the rpsL, rrs and gidB region. As the gidB protein has a complex substrate and no activity assay has yet been formulated, mutants of interest were subjected to in silico modelling and were structurally mapped together with active-site amino acid residues for assessment of the relevance to activity of the mutations found. Eight novel sense mutations and four novel mis-sense mutations in gidB were identified. Findings showed that active-site morphology is not only greatly affected by mutants lying in close proximity to the active-site pocket, but also by other mutations altering secondary-structure motifs and having an overall effect on protein structure. We conclude that gidB mutations address many unanswered questions and explain the whole story behind phenotypic streptomycin-resistant strains exhibiting no mutation in rpsL or rrs. They also validate the hypothesis of sequential progression of resistance from low to high due to the existence of gidB alterations in the genetic background. © The Author 2014. 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.

  10. Culture-independent detection of 'TM7' bacteria in a streptomycin-resistant acidophilic nitrifying process

    Energy Technology Data Exchange (ETDEWEB)

    Kurogi, T.; Linh, N. T. T.; Kuroki, T.; Yamada, T. [Department of Environmental and Life Science, Toyohashi University of Technology, Toyohashi 441-8580 (Japan); Hiraishi, A. [Department of Environmental and Life Science, Toyohashi University of Technology, Toyohashi 441-8580, Japan and Electronics-inspired Interdisciplinary Institute (EIIRIS), Toyohashi University of Technology, Toyohashi 441-8580 (Japan)

    2014-02-20

    Nitrification in biological wastewater treatment processes has been believed for long time to take place under neutral conditions and is inhibited under acidic conditions. However, we previously constructed acidophilic nitrifying sequencing-batch reactors (ANSBRs) being capable of nitrification at < pH 4 and harboring bacteria of the candidate phylum 'TM7' as the major constituents of the microbial community. In light of the fact that the 16S rRNA of TM7 bacteria has a highly atypical base substitution possibly responsible for resistance to streptomycin at the ribosome level, this study was undertaken to construct streptomycin-resistant acidophilic nitrifying (SRAN) reactors and to demonstrate whether TM7 bacteria are abundant in these reactors. The SRAN reactors were constructed by seeding with nitrifying sludge from an ANSBR and cultivating with ammonium-containing mineral medium (pH 4.0), to which streptomycin at a concentration of 10, 30 and 50 mg L{sup −1} was added. In all reactors, the pH varied between 2.7 and 4.0, and ammonium was completely converted to nitrate in every batch cycle. PCR-aided denaturing gradient gel electrophoresis (DGGE) targeting 16S rRNA genes revealed that some major clones assigned to TM7 bacteria and Gammaproteobacteria were constantly present during the overall period of operation. Fluorescence in situ hybridization (FISH) with specific oligonucleotide probes also showed that TM7 bacteria predominated in all SRAN reactors, accounting for 58% of the total bacterial population on average. Although the biological significance of the TM7 bacteria in the SRAN reactors are unknown, our results suggest that these bacteria are possibly streptomycin-resistant and play some important roles in the acidophilic nitrifying process.

  11. Conditional lethal mutants of bacteriophage T4 unable to grow on a streptomycin resistant mutant of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Childs, J.D.

    1977-01-01

    Sixteen conditional lethal mutants of bacteriophage T4D have been isolated which grow on Escherichia coli CR63 (a su/sup +/ streptomycin-sensitive K12 strain) but are restricted by CR/s (a streptomycin-resistant derivative of CR63). These mutants have been given the prefix str. Four of these mutants are amber and 12 appear to be missense. Eleven of the 12 missense mutants appear to be ''pseudo-amber'' (i.e., they are restricted by a su/sup -/ E. coli B strain but not by a su/sup -/ K12 strain); the other missense mutant was not restricted by either B or K12. The str mutations mapped in 12 different genes. Most were clustered in a region of early genes (gene 56 to gene 47). Fifty-eight amber and 10 ''pseudo-amber'' mutants isolated previously for their inability to grow on E. coli B were tested for restriction by CR/s. All the amber mutants grew normally on CR/s, whereas all 10 ''pseudo-amber'' mutants were restricted by CR/s. This implies that the phenotype of the ''pseudo-amber'' mutants is the result of a ribosomal difference between the permissive host CR63 and the restrictive hosts B and CR/s. These str mutants should prove to be useful alternatives to amber mutants for genetic and biochemical studies of bacteriophage T4 and for studies of the E. coli ribosome. It should be possible to isolate similar mutants in other bacteriophages provided that streptomycin resistant hosts are available.

  12. Evolution of Resistance to Continuously Increasing Streptomycin Concentrations in Populations of Escherichia coli.

    Science.gov (United States)

    Spagnolo, Fabrizio; Rinaldi, Conrad; Sajorda, Dannah Rae; Dykhuizen, Daniel E

    2015-12-14

    The evolution of antibiotic resistance in bacteria has become one of the defining problems in modern biology. Bacterial resistance to antimicrobial therapy threatens to eliminate one of the pillars of the practice of modern medicine. Yet, in spite of the importance of this problem, only recently have the dynamics of the shift from antibiotic sensitivity to resistance in a bacterial population been studied. In this study, a novel chemostat method was used to observe the evolution of resistance to streptomycin in a sensitive population of Escherichia coli, which grew while the concentration of antibiotic was constantly increasing. The results indicate that resistant mutants remain at a low frequency for longer than expected and do not begin to rise to a high frequency until the antibiotic concentrations are above the measured MIC, creating a "lull period" in which there were few bacterial cells growing in the chemostats. Overall, mutants resistant to streptomycin were found in >60% of the experimental trial replicates. All of the mutants detected were found to have MICs far above the maximum levels of streptomycin to which they were exposed and reached a high frequency within 96 h. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  13. A streptomycin-resistant Escherichia coli mutant with ribosomes temperature-sensitive in the suppression of a nonsense codon.

    Science.gov (United States)

    Zeevi, M; Daniel, V; Engelberg-Kulka, H

    1979-02-26

    Cell free extracts from a streptomycin-resistant E. coli mutant which is also temperature-sensitive for Q beta phage were studied for suppression of a nonsense mutation at various temperatures. The streptomycin-resistant ribosomes of the mutant were found to be temperature-sensitive in suppression of an amber mutation in f2 phage coat protein while retaining the ability to synthesize proteins at an elevated temperature (42 degrees C). The restriction of amber suppression at 42 degrees C is assumed to be related to an alteration in ribosomal protein S12 of the streptomycin-resistant mutant which also causes a change in its electrophoretic mobility.

  14. Self-transmissible antibiotic resistance to ampicillin, streptomycin, and tetracyclin found in Escherichia coli isolates from contaminated drinking water.

    Science.gov (United States)

    Walia, Satish K; Kaiser, Alan; Parkash, Mohinder; Chaudhry, G Rasul

    2004-01-01

    Presence and survival of cultivable bacteria in drinking water can act as a vehicle to disseminate virulence genes (adherence, enterotoxigenic and antibiotic resistance) to other bacteria. This can result in high morbidity and mortality, and the failure of the treatment of life threatening bacterial infections in humans and animals. In this study, antibiotic resistance (ABR) patterns and transferability of the ABR markers was investigated in Escherichia coli isolates obtained from drinking water and human urine samples. The ABR in E. coli isolates was determined against 15 antibiotics commonly used in human and veterinary medicine. A high frequency of ABR to carbenicillin (56%), tetracycline (53%) and streptomycin (49%) and a low frequency of cefizoxime (5%), amikacin (8%), cefazidine, (5%), chloramphenicol (9%), and kanamycin (18%) was found in the tested E. coli isolates. ABR to kanamycin (0% vs. 35%) and moxalactam (4% vs. 30%) was higher in drinking water isolates whereas resistance to streptomycin (92% vs. 15%), ampicillin (24% vs. 10%), and nalidixic acid (12% vs. 0%) was higher in human urine isolates. A large number of E. coli isolates (93%) exhibited resistance to two or more antibiotics. Two of E. coli isolates from drinking water showed resistances to six (Cb Cm Cx Ip Mx Tc and An Cb Km Mx Sm Tc) and one was resistant to seven antibiotics (Am An Cb Km Mx Sm Tc). A majority of the multiple antibiotic resistant E. coli isolates contained one or more plasmids (size ranged approximately 1.4 Kb to approximately 40 Kb). The ABR traits (Am and Tc) were transferable to other bacteria via conjugation. These data raise an important question about the impact of E. coli containing self-transmissible R-plasmids as a potential reservoir of virulence genes in drinking water.

  15. Defective lysis of streptomycin-resistant escherichia coli cells infected with bacteriophage f2.

    Science.gov (United States)

    De Mars Cody, J; Conway, T W

    1981-01-01

    A lysis defect was found to account for the failure of a streptomycin-resistant strain of Escherichia coli to form plaques when infected with the male-specific bacteriophage f2. The lysis defect was associated with the mutation to streptomycin resistance. Large amounts of apparently normal bacteriophage accumulated in these cells. Cell-free extracts from both the parental and mutant strains synthesized a potential lysis protein in considerable amounts in response to formaldehyde-treated f2 RNA but not in response to untreated RNA. As predicted from the nucleotide sequence of the analogous MS2 phage, the protein synthesized in vitro had the expected molecular weight and lacked glycine. The cistron for the lysis protein overlapped portions of the coat and replicase cistrons and was translated in the +1 reading frame. Initiation at the lysis protein cistron may be favored by translation errors that expose the normally masked initiation site, and streptomycin-resistant ribosomes, known to have more faithful translation properties, may be unable to efficiently synthesize the lysis protein. Images PMID:6783768

  16. Impact of resistance selection and mutant growth fitness on the relative efficacies of streptomycin and levofloxacin for plague therapy.

    Science.gov (United States)

    Louie, Arnold; Deziel, Mark R; Liu, Weiguo; Drusano, George L

    2007-08-01

    Yersinia pestis, the bacterium that causes plague, is a potential agent of biowarfare and bioterrorism. The aminoglycoside antibiotic streptomycin is the gold standard for treatment. However, this recommendation is based on scant animal and clinical data. We used an in vitro pharmacodynamic infection model to compare the efficacies of 10-day regimens of streptomycin versus the fluoroquinolone antibiotic levofloxacin for the treatment of Y. pestis infection and to evaluate for emergence of resistance. The human serum concentration-time profiles for standard clinical regimens of 1 g of streptomycin given every 12 h and 500 mg of levofloxacin given every 24 h were simulated. The growth fitness of drug-resistant mutants was examined in neutropenic and immunocompetent mouse thigh infection models. In the in vitro infection system, untreated bacteria grew from 10(7) to 10(10) CFU/ml. Streptomycin therapy caused a 10(5) CFU/ml reduction in the number of bacteria over 24 h, followed by regrowth with streptomycin-resistant mutants. Levofloxacin resulted in a 10(7) CFU/ml reduction in the number of bacteria within 12 h, ultimately sterilizing the culture without resistance selection. In both the normal and neutropenic mouse infection models, streptomycin-resistant and wild-type strains were equally fit. However, 90% of levofloxacin-resistant isolates, cultured from the control in vitro infection arm, did not proliferate in the mouse models. Thus, the fluoroquinolone antibiotic levofloxacin was superior to streptomycin in our in vitro infection model. The majority of levofloxacin-resistant mutants were less fit than streptomycin-resistant and wild-type Y. pestis.

  17. A study on the mechanism of resistance to streptomycin in ...

    African Journals Online (AJOL)

    use

    2011-12-12

    1973), and the length of lesions on the inoculated leaf was measured after 15 days. DNA isolation. DNA was isolated from the wild-type isolate and resistant strains as described by Ausubel et al. (1987). After the bacteria were ...

  18. [3H] dihydrostreptomycin accumulation and binding to ribosomes in Rhizobium mutants with different levels of streptomycin resistance.

    Science.gov (United States)

    Zelazna-Kowalska, I

    1977-10-01

    Rhizobium trifolii B1, a symbiotic nitrogen fixer, is sensitive to streptomycin (10 microgram/ml) and spontaneously produces spheroplast-like forms during cultivation. Streptomycin-resistant mutants selected with high doses of antibiotic (1,000 microgram/ml) showed pleiotropic changes, including loss of spheroplast formation and infectivity to plants, whereas mutants selected with low doses of streptomycin (10 to 100 microgram/ml) retained properties of parent strain B1 (I. Zelazna-Kowalska, Acta Microbiol. Pol., in press). The present studies revealed that strain B1 and its mutant with a high level of streptomycin resistance, B1 strH, accumulated the antibiotic at similar rates. Mutant B1 strL, with a low level of streptomycin resistance (up to 100 microgram/ml), accumulated the antibiotic at a lower rate. Ribosomes isolated from strains B1 and B2 strL bound [3H]dihydrostreptomycin, whereas those from strain B1 strH did not. These observations indicate that, in R. trifolii B1, mutation to a high level of streptomycin resistance affects ribosomal structure, whereas low-level resistance involves a change in membrane permeability.

  19. Secretory Proteome Analysis of Streptomycin-Resistant Mycobacterium tuberculosis Clinical Isolates.

    Science.gov (United States)

    Sharma, Divakar; Bisht, Deepa

    2017-12-01

    Tuberculosis still remains one of the most fatal infectious diseases. Streptomycin (SM) is the drug of choice, especially for patients with multidrug-resistant tuberculosis or category II patients, because it targets the protein synthesis machinery by interacting with steps of translation. Several mechanisms have been proposed to explain the resistance, but our knowledge is inadequate. Secretome often plays an important role in pathogenesis and is considered an attractive reservoir for the development of novel diagnostic markers and targets. In this study, we analyze the secretory proteins of streptomycin-resistant Mycobacterium tuberculosis isolates by 2-dimensional gel electrophoresis-matrix assisted laser desorption/ionization-time-of-flight mass spectrometry and bioinformatic tools. Fifteen overexpressed proteins were identified in a resistant isolate that belonged to various categories such as virulence/detoxification/adaptation, intermediary metabolism and respiration, and conserved hypotheticals. Among them, Rv1860, Rv1980c, Rv2140c, Rv1636, and Rv1926c were proteins of an undefined role. Molecular docking of these proteins with SM showed that it binds to their conserved domains and suggests that these might neutralize/compensate the effect of the drug. The interactome also suggests that overexpressed proteins along with their interactive partner might be involved in M. tuberculosis virulence and resistance. The cumulative effect of these overexpressed proteins could involve SM resistance, and these might be used as diagnostic markers or potential drug targets.

  20. Plasmid-mediated streptomycin and sulfamethoxazole resistance in Shigella flexneri 3a.

    Science.gov (United States)

    Barman, Soumik; Chatterjee, Sohini; Chowdhury, Goutam; Ramamurthy, Thandavarayan; Niyogi, Swapan Kumar; Kumar, Ranajit; Koley, Hemanta

    2010-10-01

    Shigellosis is a major cause of diarrhoea-related morbidity and mortality, especially in children in developing countries such as India. Recently, it was estimated that 91 million individuals worldwide contract shigellosis each year. The emergence and dissemination of multidrug-resistant strains of Shigella is now an emerging global health problem. During the past two decades, much attention was given to re-evaluation of treatment recommendations. In the present study, we investigated a clinical strain of Shigella flexneri 3a with multiple drug resistance. This strain was resistant to ampicillin, chloramphenicol, co-trimoxazole (trimethoprim/sulfamethoxazole), nalidixic acid, streptomycin, sulfamethoxazole, tetracycline and trimethoprim. However, it was susceptible to 46.7% of drugs tested, i.e. azithromycin, ceftriaxone, ciprofloxacin, gentamicin, kanamycin, norfloxacin and ofloxacin. A 6.3-kb plasmid was cured from this strain using acridine orange. Following curing, it was observed that 87% of drug resistance loci of S. flexneri 3a are chromosomal and 13% are plasmid-encoded. This 6.3-kb plasmid was involved in streptomycin and sulfamethoxazole resistance in S. flexneri 3a strain, which was confirmed by the disk diffusion method. Clonality was confirmed by pulse-field gel electrophoresis (PFGE). This study contributes to our knowledge on acquired drug resistance in one of the most common Shigella spp., S. flexneri 3a, which will enable better understanding of effective clinical management of shigellosis. Copyright 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  1. Phenotypic Suppression of Streptomycin Resistance by Mutations in Multiple Components of the Translation Apparatus.

    Science.gov (United States)

    Carr, Jennifer F; Lee, Hannah J; Jaspers, Joshua B; Dahlberg, Albert E; Jogl, Gerwald; Gregory, Steven T

    2015-09-01

    The bacterial ribosome and its associated translation factors are frequent targets of antibiotics, and antibiotic resistance mutations have been found in a number of these components. Such mutations can potentially interact with one another in unpredictable ways, including the phenotypic suppression of one mutation by another. These phenotypic interactions can provide evidence of long-range functional interactions throughout the ribosome and its functional complexes and potentially give insights into antibiotic resistance mechanisms. In this study, we used genetics and experimental evolution of the thermophilic bacterium Thermus thermophilus to examine the ability of mutations in various components of the protein synthesis apparatus to suppress the streptomycin resistance phenotypes of mutations in ribosomal protein S12, specifically those located distant from the streptomycin binding site. With genetic selections and strain constructions, we identified suppressor mutations in EF-Tu or in ribosomal protein L11. Using experimental evolution, we identified amino acid substitutions in EF-Tu or in ribosomal proteins S4, S5, L14, or L19, some of which were found to also relieve streptomycin resistance. The wide dispersal of these mutations is consistent with long-range functional interactions among components of the translational machinery and indicates that streptomycin resistance can result from the modulation of long-range conformational signals. The thermophilic bacterium Thermus thermophilus has become a model system for high-resolution structural studies of macromolecular complexes, such as the ribosome, while its natural competence for transformation facilitates genetic approaches. Genetic studies of T. thermophilus ribosomes can take advantage of existing high-resolution crystallographic information to allow a structural interpretation of phenotypic interactions among mutations. Using a combination of genetic selections, strain constructions, and experimental

  2. Novel mutation in 16S rRNA associated with streptomycin dependence in Mycobacterium tuberculosis.

    OpenAIRE

    Honoré, N; Marchal, G; Cole, S T

    1995-01-01

    Molecular characterization of a streptomycin-dependent mutant of Mycobacterium tuberculosis revealed the presence of a novel mutation in the rrs gene encoding 16S rRNA. Insertion of an additional cytosine in the 530 loop of 16S rRNA, a region known to be involved in streptomycin susceptibility and resistance, was associated with streptomycin dependence.

  3. [Role of the ribosomes in controlling cellular differentiation and secondary metabolism in sporulating bacteria. I. Sporogenesis, antibiotic formation and the proteolytic activity of streptomycin-resistant mutants].

    Science.gov (United States)

    Lukin, A A; Korolev, V I

    1981-01-01

    A ribosomal mutant Bacillus subtilis IG1 resistant to 100 mkg/ml of streptomycin was isolated. The strA mutation is cotransduced with the cysA gene and, consequently, maps in the ribosomal cluster. The mutation does not influence cell division but does reduce a level of sporulation as well as its antibiotic and proteolytic activity. Involvement of ribosomes in the control of sporulation and secondary metabolism of spore forming bacteria is discussed.

  4. Rapid detection of rifampicin, isoniazid and streptomycin resistance in Mycobacterium tuberculosis clinical isolates by high-resolution melting curve analysis.

    Science.gov (United States)

    Yadav, R; Sethi, S; Mewara, A; Dhatwalia, S K; Gupta, D; Sharma, M

    2012-10-01

    This study was carried out to evaluate high-resolution melting (HRM) curve analysis assay for detection of mutations in three drug resistance-associated genes of Mycobacterium tuberculosis. Clinical isolates of Myco. tuberculosis phenotypically resistant to rifampicin (n = 29), isoniazid (n = 35) and streptomycin (n = 34) were analysed for mutations in rpoB, katG and rpsL genes, respectively, by HRM curve analysis and DNA sequencing. HRM curve assay resulted in 11 clearly distinguishable melt curves denoting eight types of mutations responsible for drug resistance. For the three drugs, respectively, the sensitivity of HRM curve assay was found to be 93·1, 80 and 61·8% compared to the phenotypic resistance patterns, and 93·1, 93·3 and 100% in comparison with the DNA sequencing. The sensitivity and specificity of HRM curve assay was found to be comparable to DNA sequencing. The assay offers the advantage of high throughput, single step, rapid work flow and cost effectiveness and can be utilized as a rapid screening method for detection of drug-resistant tuberculosis. HRM curve assay may prove to be an important tool for the development of rapid molecular diagnostic assays for detection of mutation-based drug resistance. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  5. Proteomic analysis of streptomycin resistant and sensitive clinical isolates of Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Venkatesan Krishnamurthy

    2010-11-01

    Full Text Available Abstract Background Streptomycin (SM is a broad spectrum antibiotic and is an important component of any anti-tuberculosis therapy regimen. Several mechanisms have been proposed to explain the emergence of resistance but still our knowledge is inadequate. Proteins form a very complex network and drugs are countered by their modification/efflux or over expression/modification of targets. As proteins manifest most of the biological processes, these are attractive targets for developing drugs, immunodiagnostics or therapeutics. The aim of present study was to analyze and compare the protein profile of whole cell extracts from Mycobacterium tuberculosis clinical isolates susceptible and resistant to SM. Results Two-dimensional gel electrophoresis (2DE and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry was employed for analyzing the protein profiles. Homology and in silico characterization for identified proteins was assessed using BLAST, InterProScan and KEGG database searches. Computational studies on the possible interactions between SM and identified proteins were carried out by a battery of online servers and softwares, namely, CLUSTALW (KEGG, I-TASSER, VMD, PatchDock and FireDock. On comparing 2DE patterns, nine proteins were found consistently overexpressed in SM resistant isolates and were identified as Rv0350, Rv0440, Rv1240, Rv3075c, Rv2971, Rv3028c, Rv2145c, Rv2031c and Rv0569. In silico docking analysis showed significant interactions of SM with essential (Rv0350, Rv0440 and Rv2971 and non essential (Rv1240, Rv3075c and Rv2031c genes. Conclusions The computational results suggest high protein binding affinity of SM and suggested many possible interactions between identified proteins and the drug. Bioinformatic analysis proves attributive for analysis of diversity of proteins identified by whole proteome analysis. In-depth study of the these proteins will give an insight into probable sites of drug

  6. The evolution of no-cost resistance at sub-MIC concentrations of streptomycin in Streptomyces coelicolor.

    Science.gov (United States)

    Westhoff, Sanne; van Leeuwe, Tim Marijn; Qachach, Omar; Zhang, Zheren; van Wezel, Gilles Philippus; Rozen, Daniel Eric

    2017-05-01

    At the high concentrations used in medicine, antibiotics exert strong selection on bacterial populations for the evolution of resistance. However, these lethal concentrations may not be representative of the concentrations bacteria face in soil, a recognition that has led to questions of the role of antibiotics in soil environments as well as the dynamics of resistance evolution during sublethal challenge. Here we examine the evolution of resistance to sub-minimal inhibitory concentrations (sub-MIC) of streptomycin in the filamentous soil bacterium Streptomyces coelicolor. First, we show that spontaneous resistance to streptomycin causes an average fitness deficit of ~21% in the absence of drugs; however, these costs are eliminated at concentrations as low as 1/10 the MIC of susceptible strains. Using experimental evolution, we next show that resistance to >MIC levels of streptomycin readily evolves when bacteria are exposed to sub-MIC doses for 500 generations. Furthermore, the resistant clones that evolved at sub-MIC streptomycin concentrations carry no fitness cost. Whole-genome analyses reveal that evolved resistant clones fixed some of the same mutations as those isolated at high drug concentrations; however, all evolved clones carry additional mutations and some fixed mutations that either compensate for costly resistance or have no associated fitness costs. Our results broaden the conditions under which resistance can evolve in nature and suggest that rather than low-concentration antibiotics acting as signals, resistance evolves in response to antibiotics used as weapons.

  7. In vitro measurement of translation accuracy of ribosomes isolated from streptomycin-resistant mutant of Streptomyces granaticolor.

    Science.gov (United States)

    Weiser, J; Ehrenberg, M; Náprstek, J

    1994-01-01

    Accuracy of activity of ribosome isolated from UV-light-induced streptomycin-resistant R-21 mutant of Streptomyces granaticolor was measured in an E. coli-derived system translating poly(U) with a high rate and accuracy. Ribosomes from the R-21 mutant strain were shown to be resistant to streptomycin and about two-fold more accurate than those from the wild type. The mutant strain was found to be resistant to 1000 mg/L streptomycin (Stm) during vegetative growth while it sporulated on agar plates containing only up to 200 mg/L of Stm. The growth rate of the R-21 mutant in complex liquid medium was indistinguishable from that of the wild-type strain.

  8. High-resolution melting analysis for the rapid detection of fluoroquinolone and streptomycin resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Lee, Ann S G; Ong, Danny C T; Wong, Joshua C L; Siu, Gilman K H; Yam, Wing-Cheong

    2012-01-01

    Molecular methods for the detection of drug-resistant tuberculosis are potentially more rapid than conventional culture-based drug susceptibility testing, facilitating the commencement of appropriate treatment for patients with drug resistant tuberculosis. We aimed to develop and evaluate high-resolution melting (HRM) assays for the detection of mutations within gyrA, rpsL, and rrs, for the determination of fluoroquinolone and streptomycin resistance in Mycobacterium tuberculosis (MTB). A blinded series of DNA samples extracted from a total of 92 clinical isolates of MTB were analyzed by HRM analysis, and the results were verified using DNA sequencing. The sensitivity and specificity of the HRM assays in comparison with drug susceptibility testing were 74.1% and 100.0% for the detection of fluoroquinolone resistance, and 87.5% and 100.0% for streptomycin resistance. Five isolates with low level resistance to ofloxacin had no mutations detected in gyrA, possibly due to the action of efflux pumps, or false negativity due to mixed infections. One fluoroquinolone-resistant isolate had a mutation in a region of gyrA not encompassed by our assay. Six streptomycin-resistant strains had undetectable mutations by HRM and DNA sequencing, which may be explained by the fact that not all streptomycin-resistant isolates have mutations within rpsL and rrs, and suggesting that other targets may be involved. The HRM assays described here are potentially useful adjunct tests for the efficient determination of fluoroquinolone and streptomycin resistance in MTB, and could facilitate the timely administration of appropriate treatment for patients infected with drug-resistant TB.

  9. Synergistic antibacterial activity of the combination of the alkaloid sanguinarine with EDTA and the antibiotic streptomycin against multidrug resistant bacteria.

    Science.gov (United States)

    Hamoud, Razan; Reichling, Jürgen; Wink, Michael

    2015-02-01

    Drug combinations consisting of the DNA intercalating benzophenanthridine alkaloid sanguinarine, the chelator EDTA with the antibiotic streptomycin were tested against several Gram-positive and Gram-negative bacteria, including multi-resistant clinical isolates. Microdilution, checkerboard and time kill curve methods were used to investigate the antibacterial activity of the individual drugs and the potential synergistic activity of combinations. Sanguinarine demonstrated a strong activity against Gram-positive and Gram-negative bacteria (minimum inhibitory concentrations, MIC = 0.5-128 μg/ml), while streptomycin was active against Gram-negative strains (MIC = 2-128 μg/ml). EDTA showed only bacteriostatic activity. Indifference to synergistic activity was seen in the two-drug combinations sanguinarine + EDTA and sanguinarine + streptomycin (fractional inhibitory concentration index = 0.1-1.5), while the three-drug combination of sanguinarine + EDTA + streptomycin showed synergistic activity against almost all the strains (except methicillin-resistant Staphylococcus aureus), as well as a strong reduction in the effective doses (dose reduction index = 2-16 times) of sanguinarine, EDTA and streptomycin. In time kill studies, a substantial synergistic interaction of the three-drug combination was detected against Escherichia coli and Klebsiella pneumoniae. The combination of drugs, which interfere with different molecular targets, can be an important strategy to combat multidrug resistant bacteria. © 2014 Royal Pharmaceutical Society.

  10. pKJ1, a naturally occurring conjugative plasmid coding for toluene degradation and resistance to streptomycin and sulfonamides

    Energy Technology Data Exchange (ETDEWEB)

    Yano, K.; Nishi, T.

    1980-08-01

    Pseudomonas sp. TA8 isolated by m-toluate enrichment from an aqueous sample metabolized toluene and m- and p-xylenes via the meta cleavage pathway, and manifested specific resistance to streptomycin and sulfonamides. A variety of experiments revealed that the pKJ1 plasmid of about 150 megadaltons carried by TA8 specified both the toluene and xylene degradative function (the Tol function) and streptomycin/sulfonamide resistance. The deletion of a segment of pKJ1 (about 22 megadaltons) resulted in the loss of the Tol function. pKJ1 was not assigned to Pseudomonas incompatibility group P-1, P-2, P-3, or P-9.

  11. Comparative study of class 1 integron, ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline (ACSSuT) and fluoroquinolone resistance in various Salmonella serovars from humans and animals.

    Science.gov (United States)

    Hsu, Yuan-Man; Tang, Chiu-Ying; Lin, Hsuan; Chen, Yu-Hsin; Chen, Yu-Lin; Su, Yu-Heng; Chen, Daniel S; Lin, Jiunn-Horng; Chang, Chao-Chin

    2013-01-01

    A total of 499 Salmonella isolates including 9 serovars from humans and various animal hosts were collected to compare prevalence of integron and antimicrobial resistance. The integron and gene cassette were detected by PCR, and then the gene cassette type was further determined by sequencing and restriction fragment length polymorphism (RFLP) analysis. The antimicrobial susceptibility test was conducted by disk diffusion method. The positivity percentage of class 1 integron and the diversity of gene cassettes carried by integron were quite different in various Salmonella serovars, especially comparing those from animals to humans. After sequencing and RFLP analysis, it was identified eight gene cassette types. The gene cassette type D carrying ampicillin/streptomycin resistance genes was the most common one (42.2%) in the integron-positive isolates. More diversity of gene cassette types was identified in humans comparing to that in animals. Several gene cassette types were identified for the first time in some Salmonella serovars. In this study, 31.5% (157/499) of the isolates were multi-resistant to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (ACSSuT). S. Choleraesuis isolates with the cassette type A1, but S. Typhimurium isolates with the cassette type E1, were frequently associated with ACSSuT-resistant (80.6% and 72.7%, respectively). There was a significant association between the presence of class 1 integron and quinolone resistance in S. Choleraesuis isolates, but not in S. Typhimurium. Our findings imply that transmission efficiency of various gene cassettes through the integron could be different in various Salmonella serovars. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Genetic Basis, Transferability And Linkage Of Streptomycin And ...

    African Journals Online (AJOL)

    plasmids from E. coli known to mediate these resistance properties. Streptomycin resistance was based on the expression of the strA, strB and/or aadA1 genes, while sulphonamide resistance was encoded by the sul2 or sul1 gene. The strA, strB and sul2 genes were transferable via conjugation and transformation.

  13. Increased transmission of Mycobacterium tuberculosis Beijing genotype strains associated with resistance to streptomycin: a population-based study.

    Science.gov (United States)

    Buu, Tran N; van Soolingen, Dick; Huyen, Mai N T; Lan, Nguyen T N; Quy, Hoang T; Tiemersma, Edine W; Kremer, Kristin; Borgdorff, Martien W; Cobelens, Frank G J

    2012-01-01

    Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains. We studied the relative transmission fitness of the Beijing genotype in relation to anti-tuberculosis drug resistance in a population-based study of smear-positive tuberculosis patients prospectively recruited and studied over a 4-year period in rural Vietnam. Transmission fitness was analyzed by clustering of cases on basis of three DNA typing methods. Of 2531 included patients, 2207 (87%) were eligible for analysis of whom 936 (42%) were in a DNA fingerprint cluster. The clustering rate varied by genotype with 292/786 (37%) for the Beijing genotype, 527/802 (67%) for the East-African Indian (EAI) genotype, and 117/619 (19%) for other genotypes. Clustering was associated with the EAI compared to the Beijing genotype (adjusted odds ratio (OR(adj)) 3.4: 95% CI 2.8-4.4). Patients infected with streptomycin-resistant strains were less frequently clustered than patients infected with streptomycin-susceptible strains when these were of the EAI genotype (OR(adj) 0.6, 95% CI 0.4-0.9), while this pattern was reversed for strains of the Beijing genotype (OR(adj) 1.3, 95% CI 1.0-1.8, p for difference 0.002). The strong association between Beijing and MDR-TB (OR(adj) 7.2; 95% CI 4.2-12.3) existed only if streptomycin resistance was present. Beijing genotype strains showed less overall transmissibility than EAI strains, but when comparisons were made within genotypes, Beijing strains showed increased transmission fitness when streptomycin-resistant, while the reverse was observed for EAI strains. The association between MDR-TB and Beijing genotype in this population was strongly dependent on resistance to streptomycin. Streptomycin resistance may provide Beijing strains with a fitness advantage

  14. A Mutation in the Decoding Center of Thermus thermophilus 16S rRNA Suggests a Novel Mechanism of Streptomycin Resistance

    Science.gov (United States)

    Gregory, Steven T.; Carr, Jennifer F.; Dahlberg, Albert E.

    2005-01-01

    A spontaneous kanamycin resistance and capreomycin resistance mutation, A1408G, in the decoding center of 16S rRNA, was identified in the extreme thermophile Thermus thermophilus. Unexpectedly, this mutation also confers resistance to streptomycin. We propose a novel mechanism of streptomycin resistance by which A1408G influences conformational changes in 16S rRNA during tRNA selection. PMID:15743969

  15. E. coli ribosomes with a C912 to U base change in the 16S rRNA are streptomycin resistant.

    OpenAIRE

    Montandon, P E; Wagner, R; Stutz, E

    1986-01-01

    Resistance to streptomycin (Sm) of Euglena gracilis chloroplasts can be due to a single C to T transition of the 16S rRNA gene in an invariant position which is equivalent to C912 of the Escherichia coli 16S rRNA. Since Euglena chloroplasts cannot be transformed we introduced, by site-directed mutagenesis, a C912 to T transition in the cloned rrnB operon (pKK3535) of E. coli and used this new construct (pEM109) in transformation experiments. Transformed E. coli cells were selected for Sm resi...

  16. Multiple Resistance at No Cost: Rifampicin and Streptomycin a Dangerous Liaison in the Spread of Antibiotic Resistance.

    Science.gov (United States)

    Durão, Paulo; Trindade, Sandra; Sousa, Ana; Gordo, Isabel

    2015-10-01

    Evidence is mounting that epistasis is widespread among mutations. The cost of carrying two deleterious mutations, or the advantage of acquiring two beneficial alleles, is typically lower that the sum of their individual effects. Much less is known on epistasis between beneficial and deleterious mutations, even though this is key to the amount of genetic hitchhiking that may occur during evolution. This is particularly important in the context of antibiotic resistance: Most resistances are deleterious, but some can be beneficial and remarkably rifampicin resistance can emerge de novo in populations evolving without antibiotics. Here we show pervasive positive pairwise epistasis on Escherichia coli fitness between beneficial mutations, which confer resistance to rifampicin, and deleterious mutations, which confer resistance to streptomycin. We find that 65% of double resistant strains outcompete sensitive bacteria in an environment devoid of antibiotics. Weak beneficial mutations may therefore overcome strong deleterious mutations and can even render double mutants strong competitors. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  17. Wolbachia from the planthopper Laodelphax striatellus establishes a robust, persistent, streptomycin-resistant infection in clonal mosquito cells

    Science.gov (United States)

    Baldridge, G. D.; Higgins, L. A.; Witthuhn, B. A.

    2013-01-01

    The obligate intracellular bacterium, Wolbachia pipientis (Rickettsiales: Anaplasmataceae), distorts reproduction of its arthropod hosts to facilitate invasion of naïve populations. This property makes Wolbachia an attractive “gene drive” agent with potential applications in the control of insect vector populations. Genetic manipulation of Wolbachia will require in vitro systems for its propagation, genetic modification, amplification, and introduction into target insects. Here we show that Wolbachia from the planthopper, Laodelphax striatellus, establishes a robust infection in clonal C7-10 Aedes albopictus mosquito cells. Infected cells, designated C/wStr, expressed radiolabeled proteins that were enriched in cells grown in the absence of antibiotics that inhibit Wolbachia, relative to cultures grown in medium containing tetracycline and rifampicin. Using mass spectrometry, we verified that tryptic peptides from an upregulated 24 kDa band predominantly represented proteins encoded by the Wolbachia genome, including the outer surface protein, Wsp. We further showed that resistance of Wolbachia to streptomycin is associated with a K42R mutation in Wolbachia ribosomal protein S12, and that the pattern of amino acid substitutions in ribosomal protein S12 shows distinct differences in the closely related genera, Wolbachia and Rickettsia. PMID:23271364

  18. Non-enzymatic translocation in ribosomes from streptomycin-resistant mutants of Escherichia coli.

    Science.gov (United States)

    Asatryan, L S; Spirin, A S

    1975-07-10

    The capablity of ribosomes of four types of streptomycin-resistant mutants (A1, A2, A40 and A60) for non-enzymatic (EF-G--GTP-independent) translocation was tested. It was found that an A40 type mutation (amino acid replacement in position 87 of the protein S12 polypeptide chain) leads to activation of the capablity of the ribosome to perform spontaneous non-enzymatic translocation, while type A1, A2 and A60 mutations (amino acid replacements in position 42 of protein S12) does not give such an effect. Thus, it is shown that non-enzymatic translocation can be activated not only by the earlier described damage of the protein S12 by para-chloromercuribenzoate or by the complete removal of protein S12, but also by a definate mutational alteration of the protein. Preliminary data are also reported on the possibility of activating non-enzymatic translocation by combinations of mutational alterations of the ribosomal proteins other than protein S12 but interdepending with it (such as S4 and S5).

  19. Streptomycin resistance-aided genome shuffling to improve doramectin productivity of Streptomyces avermitilis NEAU1069.

    Science.gov (United States)

    Zhang, Ji; Wang, Xiangjing; Diao, Jinna; He, Hairong; Zhang, Yuejing; Xiang, Wensheng

    2013-08-01

    Genome shuffling is an efficient approach for the rapid engineering of microbial strains with desirable industrial phenotypes. In this study, a strategy of incorporating streptomycin resistance screening into genome shuffling (GS-SR) was applied for rapid improvement of doramectin production by Streptomyces avermitilis NEAU1069. The starting mutant population was generated through treatment of the spores with N-methyl-N'-nitro-N-nitrosoguanidine and ultraviolet (UV) irradiation, respectively, and five mutants with higher productivity of doramectin were selected as starting strains for GS-SR. Finally, a genetically stable strain F4-137 was obtained and characterized to be able to yield 992 ± 4.4 mg/l doramectin in a shake flask, which was 7.3-fold and 11.2-fold higher than that of the starting strain UV-45 and initial strain NEAU1069, respectively. The doramectin yield by F4-137 in a 50-l fermentor reached 930.3 ± 3.8 mg/l. Furthermore, the factors associated with the improved doramectin yield were investigated and the results suggested that mutations in ribosomal protein S12 and the enhanced production of cyclohexanecarboxylic coenzyme A may contribute to the improved performance of the shuffled strains. The random amplified polymorphic DNA analysis showed a genetic diversity among the shuffled strains, which confirmed the occurrence of genome shuffling. In conclusion, our results demonstrated that GS-SR is a powerful method for enhancing the production of secondary metabolites in Streptomyces.

  20. Transposon Tn5393e carrying the aphA1-containing transposon Tn6023 upstream of strAB does not confer resistance to streptomycin.

    Science.gov (United States)

    Cain, Amy K; Hall, Ruth M

    2011-09-01

    The simplest form of transposon Tn5393 carries the strA and strB genes that confer resistance to streptomycin, in addition to its transposition determinants. Tn5393e, made up of Tn5393 and a second transposon, Tn6023, was found in an IncHI2 plasmid, pSRC125, recovered from a multiply antibiotic-resistant Salmonella enterica serovar Typhimurium isolate of bovine origin. Tn6023 is made up of the aphA1b gene flanked by two inversely oriented copies of insertion sequence (IS) IS26 and is flanked by an 8 bp duplication. It is related to several other transposons that carry aphA1b in fragments of differing length, also flanked by copies of IS26. Tn6023 is located in the tnpR gene of Tn5393, which lies upstream of the strA and strB genes, and the combined structure was designated Tn5393e. Although neither strA nor strB contain any mutations that would inactivate them, pSRC125 does not confer resistance to streptomycin, indicating that the strA and strB genes are not expressed. In Tn5393, strA and strB are transcribed from the tnpR promoter, and in Tn5393e neither this transcript nor the transcript from the aphA1b promoter in Tn6023 must reach strAB. Tn5393e was previously found in different locations in Corynebacteria, indicating that it can move and suggesting a wide distribution. The structures of several further variants of Tn5393 found in GenBank were analyzed and assigned variant designations Tn5393f-Tn5393i.

  1. 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...

  2. Culture-based study on the development of antibiotic resistance in a biological wastewater system treating stepwise increasing doses of streptomycin.

    Science.gov (United States)

    Selvaraj, Ganesh-Kumar; Tian, Zhe; Zhang, Hong; Jayaraman, Mohanapriya; Yang, Min; Zhang, Yu

    2018-01-25

    The effects of streptomycin (STM) on the development of antibiotic resistance in an aerobic-biofilm reactor was explored by stepwise increases in STM doses (0-50 mg L -1 ), over a period of 618 days. Totally 191 bacterial isolates affiliated with 90 different species were harvested from the reactor exposed to six STM exposures. Gammaproteobacteria (20-31.8%), Bacilli (20-35.7%), Betaproteobacteria (4.5-21%) and Actinobacteria (0-18.2%) were dominant, and their diversity was not affected over the whole period. Thirteen dominant isolates from each STM exposures (78 isolates) were applied to determine their resistance prevalence against eight classes of antibiotics. Increased STM resistance (53.8-69.2%) and multi-drug resistance (MDR) (46.2-61.5%) were observed in the STM exposures (0.1-50 mg L -1 ), compared to exposure without STM (15.3 and 0%, respectively). Based on their variable minimum inhibitory concentration results, 40 differentiated isolates from various STM exposures were selected to check the prevalence of nine aminoglycoside resistance genes (aac(3)-II, aacA4, aadA, aadB, aadE, aphA1, aphA2, strA and strB) and two class I integron genes (3'-CS and IntI). STM resistance genes (aadA, strA and strB), a non-STM resistance gene (aacA4) and integron genes (3'-CS and Int1) were distributed widely in all STM exposures, compared to the exposure without STM. This new culture-based stepwise increasing antibiotic approach reveals that biological systems treating wastewater with lower STM dose (0.1 mg L -1 ) could lead to notably increased levels of STM resistance, MDR, and resistant gene determinants, which were sustainable even under higher STM doses (> 25 mg L -1 ).

  3. The Escherichia coli K-12 gntP gene allows E. coli F-18 to occupy a distinct nutritional niche in the streptomycin-treated mouse large intestine

    DEFF Research Database (Denmark)

    Sweeney, N.J.; Klemm, Per; McCormick, Beth A.

    1996-01-01

    Escherichia coli F-18 is a human fecal isolate that makes type 1 fimbriae, encoded by the fim gene cluster, and is an excellent colonizer of the streptomycin-treated mouse intestine. E. coli F-18 fimA::tet, lacking type 1 fimbriae, was constructed by bacteriophage P1 transduction of the fim region...... of the E. coli K-12 strain ORN151, containing the tetracycline resistance gene from Tn10 inserted in the fimA gene, into E. coli F-18. E. coli F-18 fimA::tet was found to occupy a distinct niche in the streptomycin-treated mouse intestine when fed in small numbers to mice, along with large numbers of E....... coli F-18, as defined by the ability of the E. coli F-18 fimA::tet strain to grow and colonize only 1 order of magnitude below E. coli F-18. The same effect was observed when mice already colonized with E. coli F-18 were fed small numbers of E. coli F-18 fimA::tet. Experiments which show that the E...

  4. One-tube loop-mediated isothermal amplification combined with restriction endonuclease digestion and ELISA for colorimetric detection of resistance to isoniazid, ethambutol and streptomycin in Mycobacterium tuberculosis isolates.

    Science.gov (United States)

    Lee, Mei-Feng; Chen, Yen-Hsu; Hsu, Hui-Jine; Peng, Chien-Fang

    2010-10-01

    In this study, we designed a simple and rapid colorimetric detection method, a one-tube loop-mediated isothermal amplification (LAMP)-PCR-hybridization-restriction endonuclease-ELISA [one-tube LAMP-PCR-HY-RE-ELISA] system, to detect resistance to isoniazid, ethambutol and streptomycin in strains of Mycobacterium tuberculosis isolated from clinical specimens. The clinical performance of this method for detecting isoniazid-resistant, ethambutol-resistant and streptomycin-resistant isolates of M. tuberculosis showed 98.9%, 94.3% and 93.8%, respectively. This assay is rapid and convenient that can be performed within one working day. One-tube LAMP-PCR-HY-RE-ELISA system was designed based on hot spot point mutations in target drug-resistant genes, using LAMP-PCR, hybridization, digestion with restriction endonuclease and colorimetric method of ELISA. In this study, LAMP assay was used to amplify DNA from drug-resistant M. tuberculosis, and ELISA was used for colorimetrical determination. This assay will be a useful tool for rapid diagnosis of mutant codons in strains of M. tuberculosis for isoniazid at katG 315 and katG 463, ethambutol at embB 306 and embB 497, and streptomycin at rpsL 43. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

  5. Simplified microarray system for simultaneously detecting rifampin, isoniazid, ethambutol, and streptomycin resistance markers in Mycobacterium tuberculosis.

    Science.gov (United States)

    Linger, Yvonne; Kukhtin, Alexander; Golova, Julia; Perov, Alexander; Lambarqui, Amine; Bryant, Lexi; Rudy, George B; Dionne, Kim; Fisher, Stefanie L; Parrish, Nicole; Chandler, Darrell P

    2014-06-01

    We developed a simplified microarray test for detecting and identifying mutations in rpoB, katG, inhA, embB, and rpsL and compared the analytical performance of the test to that of phenotypic drug susceptibility testing (DST). The analytical sensitivity was estimated to be at least 110 genome copies per amplification reaction. The microarray test correctly detected 95.2% of mutations for which there was a sequence-specific probe on the microarray and 100% of 96 wild-type sequences. In a blinded analysis of 153 clinical isolates, microarray sensitivity for first-line drugs relative to phenotypic DST (true resistance) was 100% for rifampin (RIF) (14/14), 90.0% for isoniazid (INH) (36/40), 70% for ethambutol (EMB) (7/10), and 89.1% (57/64) combined. Microarray specificity (true susceptibility) for first-line agents was 95.0% for RIF (132/139), 98.2% for INH (111/113), and 98.6% for EMB (141/143). Overall microarray specificity for RIF, INH, and EMB combined was 97.2% (384/395). The overall positive and negative predictive values for RIF, INH, and EMB combined were 84.9% and 98.3%, respectively. For the second-line drug streptomycin (STR), overall concordance between the agar proportion method and microarray analysis was 89.5% (137/153). Sensitivity was 34.8% (8/23) because of limited microarray coverage for STR-conferring mutations, and specificity was 99.2% (129/130). All false-susceptible discrepant results were a consequence of DNA mutations that are not represented by a specific microarray probe. There were zero invalid results from 220 total tests. The simplified microarray system is suitable for detecting resistance-conferring mutations in clinical M. tuberculosis isolates and can now be used for prospective trials or integrated into an all-in-one, closed-amplicon consumable. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  6. Establishing streptomycin epidemiological cut-off values for Salmonella and Escherichia coli. Microbial Drug Resistance

    NARCIS (Netherlands)

    Garcia-Migura, L.; Sunde, M.; Karlsmose, S.; Veldman, K.T.; Schroeter, A.; Guerra, B.; Granier, S.A.; Perrin-Guyomard, A.; Gicquel-Bruneau, M.; Franco, A.; Englund, S.; Teale, C.; Heiska, H.; Clemente, L.; Boerlin, P.; Moreno, M.A.; Daignault, D.; Mevius, D.J.; Hendriksen, R.S.; Aarestrup, F.M.

    2012-01-01

    This study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ECOFF) for Escherichia coli and Salmonella spp. A total of 236 Salmonella enterica and 208 E. coli isolates exhibiting MICs between 4 and 32¿mg/L were selected from 12 countries. Isolates

  7. Evaluation of the MeltPro TB/STR assay for rapid detection of streptomycin resistance in Mycobacterium tuberculosis.

    Science.gov (United States)

    Zhang, Ting; Hu, Siyu; Li, Guoli; Li, Hui; Liu, Xiaoli; Niu, Jianjun; Wang, Feng; Wen, Huixin; Xu, Ye; Li, Qingge

    2015-03-01

    Rapid and comprehensive detection of drug-resistance is essential for the control of tuberculosis, which has facilitated the development of molecular assays for the detection of drug-resistant mutations in Mycobacterium tuberculosis. We hereby assessed the analytical and clinical performance of an assay for streptomycin-resistant mutations. MeltPro TB/STR is a closed-tube, dual-color, melting curve analysis-based, real-time PCR test designed to detect 15 streptomycin-resistant mutations in rpsL 43, rpsL 88, rrs 513, rrs 514, rrs 517, and rrs 905-908 of M. tuberculosis. Analytical studies showed that the accuracy was 100%, the limit of detection was 50-500 bacilli per reaction, the reproducibility in the form of Tm variation was within 1.0 °C, and we could detect 20% STR resistance in mixed bacterial samples. The cross-platform study demonstrated that the assay could be performed on six models of real-time PCR instruments. A multicenter clinical study was conducted using 1056 clinical isolates, which were collected from three geographically different healthcare units, including 709 STR-susceptible and 347 STR-resistant isolates characterized on Löwenstein-Jensen solid medium by traditional drug susceptibility testing. The results showed that the clinical sensitivity and specificity of the MeltPro TB/STR was 88.8% and 95.8%, respectively. Sequencing analysis confirmed the accuracy of the mutation types. Among all the 8 mutation types detected, rpsL K43R (AAG → AGG), rpsL K88R (AAG → AGG) and rrs 514 A → C accounted for more than 90%. We concluded that MeltPro TB/STR represents a rapid and reliable assay for the detection of STR resistance in clinical isolates. Copyright © 2014. Published by Elsevier Ltd.

  8. Rapid speciation of 15 clinically relevant mycobacteria with simultaneous detection of resistance to rifampin, isoniazid, and streptomycin in Mycobacterium tuberculosis complex.

    Science.gov (United States)

    Shenai, Shubhada; Rodrigues, Camilla; Mehta, Ajita

    2009-01-01

    To design and standardize an in-house reverse line blot hybridization (RLBH) assay for the accurate identification of 15 clinically relevant species of mycobacteria and for the detection of drug resistance to rifampin (RIF), isoniazid (INH), and streptomycin (STR) in Mycobacterium tuberculosis complex (MTB). Oligonucleotides specific for 15 different species of mycobacteria and wild type and mutant alleles of selected codons in the rpobeta, inhA, katG, rpsL, and rrs genes were designed and immobilized on a membrane. A multiplex PCR was standardized to amplify all target genes. The assay was optimized using ATCC and known mutant strains. Three hundred MTB isolates, 85 non-tuberculous mycobacteria (NTM) isolates, and 48 smear-positive specimens were analyzed. Results were confirmed by PCR restriction enzyme assay and sequencing. Upon RLBH analysis, among the NTM, 14% were identified as Mycobacterium fortuitum, 16% were identified as Mycobacterium abscessus, 20% showed 99% homology with Mycobacterium intracellulare, and 31% showed 98% homology with Mycobacterium simiae. Of the 300 MTB isolates analyzed, 75% RIF-resistant isolates had Ser531Leu mutation in the rpobeta gene. Of the INH-resistant isolates, 89% showed Ser315Thr mutation in the katG gene, whereas 16% showed -15 C-->T mutation in the promoter region of the inhA gene. Among STR-resistant isolates, 75% had A-->G mutation in the rpsL gene at codon 43. RLBH results showed 96-99% concordance with phenotypic culture results. This is a first attempt at combining speciation with detection of drug resistance to RIF, INH, and STR in MTB for accurate and rapid management of mycobacterial infections as well as for compiling genotypic epidemiological data.

  9. The mthA mutation conferring low-level resistance to streptomycin enhances antibiotic production in Bacillus subtilis by increasing the S-adenosylmethionine pool size.

    Science.gov (United States)

    Tojo, Shigeo; Kim, Ji-Yun; Tanaka, Yukinori; Inaoka, Takashi; Hiraga, Yoshikazu; Ochi, Kozo

    2014-04-01

    Certain Str(r) mutations that confer low-level streptomycin resistance result in the overproduction of antibiotics by Bacillus subtilis. Using comparative genome-sequencing analysis, we successfully identified this novel mutation in B. subtilis as being located in the mthA gene, which encodes S-adenosylhomocysteine/methylthioadenosine nucleosidase, an enzyme involved in the S-adenosylmethionine (SAM)-recycling pathways. Transformation experiments showed that this mthA mutation was responsible for the acquisition of low-level streptomycin resistance and overproduction of bacilysin. The mthA mutant had an elevated level of intracellular SAM, apparently acquired by arresting SAM-recycling pathways. This increase in the SAM level was directly responsible for bacilysin overproduction, as confirmed by forced expression of the metK gene encoding SAM synthetase. The mthA mutation fully exerted its effect on antibiotic overproduction in the genetic background of rel(+) but not the rel mutant, as demonstrated using an mthA relA double mutant. Strikingly, the mthA mutation activated, at the transcription level, even the dormant ability to produce another antibiotic, neotrehalosadiamine, at concentrations of 150 to 200 μg/ml, an antibiotic not produced (<1 μg/ml) by the wild-type strain. These findings establish the significance of SAM in initiating bacterial secondary metabolism. They also suggest a feasible methodology to enhance or activate antibiotic production, by introducing either the rsmG mutation to Streptomyces or the mthA mutation to eubacteria, since many eubacteria have mthA homologues.

  10. Strong decrease in streptomycin-resistance and absence of XDR 12 years after the Reorganization of the National Tuberculosis Control Program in the Central Region of Cameroon.

    Science.gov (United States)

    Sidze, Larissa Kamgue; Mouafo Tekwu, Emmanuel; Kuaban, Christopher; Assam Assam, Jean-Paul; Tedom, Jean-Claude; Eyangoh, Sara; Fouda, François-Xavier; Nolna, Désiré; Ntoumi, Francine; Frank, Matthias; Penlap Beng, Véronique N

    2014-01-01

    In the 1990s, resistance rates of 15% for streptomycin-resistance and 0.6% for multidrug-resistance (MDR) were reported from the Central Region of Cameroon. This work assesses drug resistant tuberculosis in this region 12 years after reorganization of the National Tuberculosis Control Program (NTCP). This cross-sectional study was conducted from April 2010 to March 2011 in Jamot Hospital in Yaoundé, Cameroon. Only patients with smear positive pulmonary tuberculosis were included. Sputa were cultured and subsequently underwent drug susceptibility testing (DST). All consenting individuals were tested for their HIV status. A total of 665 smear positive pulmonary tuberculosis patients were enrolled. The HIV prevalence was 28.5% (95%CI [25.2-32.1]). Of the 582 sputa that grew Mycobacterium tuberculosis complex species, DST results were obtained for 576. The overall resistance rate was 10.9% (63/576). The overall resistance rates for single drug resistance were: isoniazid-resistance 4.7% (27/576), streptomycin-resistance 3.3% (19/576), rifampicin-resistance 0.2% (1/576), kanamycin-resistance 0.2% (1/576) and ofloxacin-resistance 0.2% (1/576). The MDR rate was 1.1% (6/576) and no extensively drug resistant tuberculosis (XDR) was detected. The data show that reorganization of the NTCP resulted in a strong decrease in streptomycin-resistance and suggest that it prevented the emergence of XDR in the Central Region of Cameroon.

  11. A streptomycin resistance marker inH. parasuisbased on site-directed mutations inrpsLgene to perform unmarked in-frame mutations and to verify natural transformation.

    Science.gov (United States)

    Dai, Ke; Wen, Xintian; Chang, Yung-Fu; Cao, Sanjie; Zhao, Qin; Huang, Xiaobo; Wu, Rui; Huang, Yong; Yan, Qigui; Han, Xinfeng; Ma, Xiaoping; Wen, Yiping

    2018-01-01

    Haemophilus parasuis is a member of the family Pasteurellaceae and a major causative agent of Glässer's disease. This bacterium is normally a benign swine commensal but may become a deadly pathogen upon penetration into multiple tissues, contributing to severe lesions in swine. We have established a successive natural transformation-based markerless mutation system in this species. However, the two-step mutation system requires screening of natural competent cells, and cannot delete genes which regulate natural competence per se. In this study, we successfully obtained streptomycin-resistant derivatives from H. parasuis wild type strain SC1401 by using ethyl methane sulfonate (EMS, CH 3 SO 2 OC 2 H 5 ). Upon sequencing and site-directed mutations, we uncovered that the EMS-induced point mutation in rpsL at codon 43rd (AAA → AGA; K43R) or at 88th (AAA → AGA; K88R) confers a much higher streptomycin resistance than clinical isolates. We have applied the streptomycin resistance marker as a positive selection marker to perform homologous recombination through conjugation and successfully generated a double unmarked in-frame targeted mutant 1401D88△ tfox △ arcA . Combined with a natural transformation-based knockout system and this genetic technique, multiple deletion mutants or attenuated strains of H. parasuis can be easily constructed. Moreover, the mutant genetic marker rpsL and streptomycin resistant phenotypes can serve as an effective tool to select naturally competent strains, and to verify natural transformation quantitatively.

  12. Genetic analysis of streptomycin-resistant (Sm(R)) strains of Erwinia amylovora suggests that dissemination of two genotypes is responsible for the current distribution of Sm(R) E. amylovora in Michigan.

    Science.gov (United States)

    McGhee, Gayle C; Guasco, Jesse; Bellomo, Lisa M; Blumer-Schuette, Sara E; Shane, William W; Irish-Brown, Amy; Sundin, George W

    2011-02-01

    Streptomycin-resistant (Sm(R)) strains of the fire blight pathogen Erwinia amylovora were first isolated in southwest Michigan in 1991. Since that time, resistant strains have progressed northward to other apple-producing regions in the state. A total of 98.7% of Sm(R) strains isolated between 2003 and 2009 in Michigan harbored the strA-strB genes on transposon Tn5393. strA and strB encode phosphotransferase enzymes that modify streptomycin to a nonbactericidal form. Mutational resistance to streptomycin, caused by a point mutation-mediated target-site alteration of the ribosomal S12 protein, occurred in 1.3% of E. amylovora strains from Michigan. Tn5393 was originally introduced to E. amylovora on the plasmid pEa34; thus, the first Sm(R) strains isolated contained both pEa34 and the ubiquitous nonconjugative plasmid pEA29. More recently, we have observed Sm(R) strains in which Tn5393 is present on pEA29, suggesting that the transposon has moved via transposition from pEa34 to pEA29. Almost all of the strains containing Tn5393 on pEA29 had lost pEa34. Of 210 pEA29::Tn5393 plasmids examined, the transposon was inserted at either nucleotide position 1,515 or 17,527. Both of these positions were in noncoding regions of pEA29. Comparative sequencing of the housekeeping genes groEL and potentially variable sequences on pEA29 was done in an attempt to genetically distinguish Sm(R) strains from streptomycin-sensitive (Sm(S)) strains isolated in Michigan. Only 1 nucleotide difference within the total 2,660 bp sequenced from each strain was observed in 2 of 29 strains; multiple sequence differences were observed between the Michigan strains and E. amylovora control strains isolated in the western United States or from Rubus spp. Alterations in virulence observable using an immature pear fruit assay were detected in three of eight Sm(R) strains examined. Our current genetic data indicate that only two Sm(R) strain genotypes (strains containing pEA29::Tn5393 with Tn5393

  13. Restrictive Streptomycin Resistance Mutations Decrease the Formation of Attaching and Effacing Lesions in Escherichia coli O157:H7 Strains.

    Science.gov (United States)

    Chen, Chun; Blumentritt, Carla A; Curtis, Meredith M; Sperandio, Vanessa; Torres, Alfredo G; Dudley, Edward G

    2013-09-01

    Streptomycin binds to the bacterial ribosome and disrupts protein synthesis by promoting misreading of mRNA. Restrictive mutations on the ribosomal subunit protein S12 confer a streptomycin resistance (Str r ) phenotype and concomitantly increase the accuracy of the decoding process and decrease the rate of translation. Spontaneous Str r mutants of Escherichia coli O157:H7 have been generated for in vivo studies to promote colonization and to provide a selective marker for this pathogen. The locus of enterocyte effacement (LEE) of E. coli O157:H7 encodes a type III secretion system (T3SS), which is required for attaching and effacing to the intestinal epithelium. In this study, we observed decreases in both the expression and secretion levels of the T3SS translocated proteins EspA and EspB in E. coli O157:H7 Str r restrictive mutants, which have K42T or K42I mutations in S12. However, mildly restrictive (K87R) and nonrestrictive (K42R) mutants showed slight or indistinguishable changes in EspA and EspB secretion. Adherence and actin staining assays indicated that restrictive mutations compromised the formation of attaching and effacing lesions in E. coli O157:H7. Therefore, we suggest that E. coli O157:H7 strains selected for Str r should be thoroughly characterized before in vivo and in vitro experiments that assay for LEE-directed phenotypes and that strains carrying nonrestrictive mutations such as K42R make better surrogates of wild-type strains than those carrying restrictive mutations. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

  14. The fitness cost of streptomycin resistance depends on rpsL mutation, carbon source and RpoS (sigmaS).

    Science.gov (United States)

    Paulander, Wilhelm; Maisnier-Patin, Sophie; Andersson, Dan I

    2009-10-01

    Mutations that cause antibiotic resistance often produce associated fitness costs. These costs have a detrimental effect on the fate of resistant organisms in natural populations and could be exploited in designing drugs, therapeutic regimes, and intervention strategies. The streptomycin resistance (StrR) mutations K42N and P90S in ribosomal protein S12 impair growth on rich medium. Surprisingly, in media with poorer carbon sources, the same StrR mutants grow faster than wild type. This improvement reflects a failure of these StrR mutants to induce the stress-inducible sigma factor RpoS (sigmaS), a key regulator of many stationary-phase and stress-inducible genes. On poorer carbon sources, wild-type cells induce sigmaS, which retards growth. By not inducing sigmaS, StrR mutants escape this self-imposed inhibition. Consistent with this interpretation, the StrR mutant loses its advantage over wild type when both strains lack an RpoS (sigmaS) gene. Failure to induce sigmaS produced the following side effects: (1) impaired induction of several stress-inducible genes, (2) reduced tolerance to thermal stress, and (3) reduced translational fidelity. These results suggest that RpoS may contribute to long-term cell survival, while actually limiting short-term growth rate under restrictive growth conditions. Accordingly, the StrR mutant avoids short-term growth limitation but is sensitized to other stresses. These results highlight the importance of measuring fitness costs under multiple experimental conditions not only to acquire a more relevant estimate of fitness, but also to reveal novel physiological weaknesses exploitable for drug development.

  15. Strong Decrease in Streptomycin-Resistance and Absence of XDR 12 Years after the Reorganization of the National Tuberculosis Control Program in the Central Region of Cameroon

    Science.gov (United States)

    Kuaban, Christopher; Assam Assam, Jean-Paul; Tedom, Jean-Claude; Eyangoh, Sara; Fouda, François-Xavier; Nolna, Désiré; Ntoumi, Francine; Frank, Matthias; Penlap Beng, Véronique N.

    2014-01-01

    Background In the 1990s, resistance rates of 15% for streptomycin-resistance and 0.6% for multidrug-resistance (MDR) were reported from the Central Region of Cameroon. This work assesses drug resistant tuberculosis in this region 12 years after reorganization of the National Tuberculosis Control Program (NTCP). Methods This cross-sectional study was conducted from April 2010 to March 2011 in Jamot Hospital in Yaoundé, Cameroon. Only patients with smear positive pulmonary tuberculosis were included. Sputa were cultured and subsequently underwent drug susceptibility testing (DST). All consenting individuals were tested for their HIV status. Results A total of 665 smear positive pulmonary tuberculosis patients were enrolled. The HIV prevalence was 28.5% (95%CI [25.2–32.1]). Of the 582 sputa that grew Mycobacterium tuberculosis complex species, DST results were obtained for 576. The overall resistance rate was 10.9% (63/576). The overall resistance rates for single drug resistance were: isoniazid-resistance 4.7% (27/576), streptomycin-resistance 3.3% (19/576), rifampicin-resistance 0.2% (1/576), kanamycin-resistance 0.2% (1/576) and ofloxacin-resistance 0.2% (1/576). The MDR rate was 1.1% (6/576) and no extensively drug resistant tuberculosis (XDR) was detected. Conclusions The data show that reorganization of the NTCP resulted in a strong decrease in streptomycin-resistance and suggest that it prevented the emergence of XDR in the Central Region of Cameroon. PMID:24901982

  16. In Vitro Antibacterial Activity of Phlorotannins from Edible Brown Algae,Eisenia bicyclisAgainst Streptomycin-ResistantListeria monocytogenes.

    Science.gov (United States)

    Kim, Hyo-Jung; Dasagrandhi, Chakradhar; Kim, Song-Hee; Kim, Bo-Geum; Eom, Sung-Hwan; Kim, Young-Mog

    2018-03-01

    Listeria monocytogenes (LM) is an important food borne pathogen responsible for listeriosis. Further, LM is an etiological agent associated with life threatening conditions like meningitis and encephalitis. Biofilm forming and drug resistant LM may potentially become difficult to treat infections and hence effective controlling measures are required to prevent LM infections. In view of this, the present study evaluated an anti-listerial potential of edible brown seaweed, Eisenia bicyclis , by disc diffusion and micro-dilution methods. The results of the present study suggested that the anti-listerial activity of various phlorotannins isolated form E. bicyclis were in the range of 16-256 µg/ml. Among the phlorotannins isolated, fucofuroeckol-A (FAA) exhibited the highest anti-listerial potential (MIC range 16-32 µg/ml) against LM strains tested. Further, in checker board synergy assays, FFA-streptomycin combination exhibited significant synergy (fractional inhibitory concentration index, ∑FIC < 0.5) against aminoglycoside resistant clinical strains of LM. The results of the present study suggested the potential use of edible seaweed E. bicyclis as a source of natural phlorotannins to control food borne pathogenic infections.

  17. Assessment of strains of Pseudomonas syringae pv. tomato from Tanzania for resistance to copper and streptomycin

    DEFF Research Database (Denmark)

    Shenge, K.C.; Wydra, K.; Mabagala, M.B.

    2008-01-01

    Fifty-six strains of Pseudomonas syringae pv. tomato (P.s. pv. tomato) were collected from tomato-producing areas in Tanzania and assessed for resistance to copper and antibiotics. The collection was done from three tomato-producing regions (Morogoro, Arusha and Iringa), representing three...... different ecological conditions in the country. After isolation and identification, the P. s. pv. tomato strains were grown on King's medium B (KB) amended with 20% copper sulphate (w/v). The strains were also assessed for resistance to antibiotics. Results indicated that there was widespread resistance...... of the P. s. pv. tomato strains to copper sulphate. The highest level of resistance was recorded from the Arusha region (Northern Tanzania), 83.3% of the P. s. pv. tomato strains from that region showed resistance to copper sulphate. This was followed by Iringa region (Southern Tanzania), from where...

  18. Mutations in rpsL that confer streptomycin resistance show pleiotropic effects on virulence and the production of a carbapenem antibiotic in Erwinia carotovora.

    Science.gov (United States)

    Barnard, Anne M L; Simpson, Natalie J L; Lilley, Kathryn S; Salmond, George P C

    2010-04-01

    Spontaneous streptomycin-resistant derivatives of Erwinia carotovora subsp. carotovora strain ATTn10 were isolated. Sequencing of the rpsL locus (encoding the ribosomal protein S12) showed that each mutant was missense, with a single base change, resulting in the substitution of the wild-type lysine by arginine, threonine or asparagine at codon 43. Phenotypic analyses showed that the rpsL mutants could be segregated into two groups: K43R mutants showed reduced production of the beta-lactam secondary metabolite 1-carbapen-2-em-3 carboxylic acid (Car), but little effect on exoenzyme production or virulence in potato tuber tests. By contrast, the K43N and K43T mutations were pleiotropic, resulting in reduced exoenzyme production and virulence, as well as diminished Car production. The effect on Car production was due to reduced transcription of the quorum-sensing-dependent car biosynthetic genes. The effects of K43N and K43T mutations on Car production were partially alleviated by provision of an excess of the quorum-sensing signalling molecule N-(3-oxohexanoyl)-L-homoserine lactone. Finally, a proteomic analysis of the K43T mutant indicated that the abundance of a subset of intracellular proteins was affected by this rpsL mutation.

  19. Improved ethanol tolerance and ethanol production from glycerol in a streptomycin-resistant Klebsiella variicola mutant obtained by ribosome engineering.

    Science.gov (United States)

    Suzuki, Toshihiro; Seta, Kohei; Nishikawa, Chiaki; Hara, Eri; Shigeno, Toshiya; Nakajima-Kambe, Toshiaki

    2015-01-01

    To improve the ethanol tolerance of the Klebsiella variicola strain TB-83, we obtained the streptomycin-resistant, ethanol-tolerant mutant strain TB-83D by a ribosome engineering approach. Strain TB-83D was able to grow in the presence of 7% (v/v) ethanol and it showed higher ethanol production than strain TB-83. Examination of various culture conditions revealed that yeast extract was essential for ethanol production and bacterial growth. In addition, ethanol production was elevated to 32g/L by the addition of yeast extract; however, ethanol production was inhibited by formate accumulation. With regard to cost reduction, the use of corn steep liquor (CSL) markedly decreased the formate concentration, and 34g/L ethanol was produced by combining yeast extract with CSL. Our study is the first to improve ethanol tolerance and productivity by a ribosome engineering approach, and we found that strain TB-83D is effective for ethanol production from glycerol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. A kirromycin-resistant EF-Tu species reverses streptomycin dependence of Escherichia coli strains mutated in ribosomal protein S12.

    Science.gov (United States)

    Zuurmond, A M; Zeef, L A; Kraal, B

    1998-12-01

    Streptomycin dependence can be caused by mutations in ribosomal protein S12. Mutations suppressing such streptomycin dependence have been found in ribosomal proteins S4 and S5, and in 16S rRNA. Here a new suppressor mutation localized in elongation factor Tu (EF-Tu) is described, consistent with recent models of ribosome-EF-Tu-tRNA interaction at the decoding centre. The EF-Tu mutation was obtained by genetic selection for streptomycin independence; it was identified as Ala375 --> Thr, previously described as EF-TuA(R) and known to confer a kirromycin-resistant, error-prone phenotype. Also, other streptomycin-dependent (SmD) S12 mutations could be complemented by this mutation. The streptomycin-independent (Sm1) strain grows more slowly than the wild-type (wt), suggesting that not all the defects of the S12 mutation can be complemented by EF-Tu[A375T]. Moreover, this strain is more susceptible than wt to reduction in the cellular EF-Tu concentration, and disruption of tufB led to considerable growth-rate impairment. Expression of EF-Tu from tufB, not only of wt EF-Tu and EF-Tu[A375T] but, remarkably, also of EF-Tu[G222D], known as EF-TuB0 and defective in protein synthesis, equally contributed to cell growth. In vitro analysis revealed a decreased translational activity of wt EF-Tu with SmD ribosomes as compared to EF-Tu[A375T], while EF-Tu[G222D] showed no activity at all, just as with wt ribosomes. Possible mechanisms are discussed for the improved growth rate observed in such Sm1 strains when they include wt EF-Tu or EF-Tu[G222D].

  1. Phenotypic Suppression of Streptomycin Resistance by Mutations in Multiple Components of the Translation Apparatus

    OpenAIRE

    Carr, Jennifer F.; Lee, Hannah J.; Jaspers, Joshua B.; Dahlberg, Albert E.; Jogl, Gerwald; Gregory, Steven T.

    2015-01-01

    The bacterial ribosome and its associated translation factors are frequent targets of antibiotics, and antibiotic resistance mutations have been found in a number of these components. Such mutations can potentially interact with one another in unpredictable ways, including the phenotypic suppression of one mutation by another. These phenotypic interactions can provide evidence of long-range functional interactions throughout the ribosome and its functional complexes and potentially give insig...

  2. Antimicrobial resistance and resistance gene determinants in clinical Escherichia coli from different animal species in Switzerland.

    Science.gov (United States)

    Lanz, Roland; Kuhnert, Peter; Boerlin, Patrick

    2003-01-02

    Antimicrobial susceptibility testing was performed on a total of 581 clinical Escherichia coli isolates from diarrhea and edema disease in pigs, from acute mastitis in dairy cattle, from urinary tract infections in dogs and cats, and from septicemia in laying hens collected in Switzerland between 1999 and 2001. Among the 16 antimicrobial agents tested, resistance was most frequent for sulfonamides, tetracycline, and streptomycin. Isolates from swine presented significantly more resistance than those from the other animal species. The distribution of the resistance determinants for sulfonamides, tetracycline, and streptomycin was assessed by hybridization and PCR in resistant isolates. Significant differences in the distribution of resistance determinants for tetracycline (tetA, tetB) and sulfonamides (sulII) were observed between the isolates from swine and those from the other species. Resistance to sulfonamides could not be explained by known resistance mechanisms in more than a quarter of the sulfonamide-resistant and sulfonamide-intermediate isolates from swine, dogs and cats. This finding suggests that one or several new resistance mechanisms for sulfonamides may be widespread among E. coli isolates from these animal species. The integrase gene (intI) from class I integrons was detected in a large proportion of resistant isolates in association with the sulI and aadA genes, thus demonstrating the importance of integrons in the epidemiology of resistance in clinical E. coli isolates from animals.

  3. [Emergence of high-level resistance to gentamicin and streptomycin in Streptococcus agalactiae in Buenos Aires, Argentina].

    Science.gov (United States)

    Villar, Hugo Edgardo; Jugo, Mónica Beatriz

    2013-06-01

    Streptococcus agalactiae has become recognized as a cause of serious illness in newborns, pregnant women, and adults with chronic medical conditions. Optimal antimicrobial therapy for serious infections requires the use of synergistic combinations of a cell wall-active agent, such as a penicillin, with an aminoglycoside, which results in bactericidal activity against this organism. The synergistic effect is eliminated by the acquisition of high-level resistance (HLR) to aminoglycosides. The aim of our study was to determine the prevalence of HLR to gentamicin (GEN) and streptomycin (EST).The ability to detect HLR using a standard agar screen plate and high-content discs was investigated. This study was conducted with 141 strains of S. agalactiae isolated from vaginal and rectal swabs of pregnant women at term. Minimum inhibitory concentrations (MICs) to GEN and STR were determined by the E-test method. Disks of GEN (120 μg) and STR (300 μg) were used to detect HLR. Agar screening plates were performed with GEN 100 mg/L, GEN 500 mg/L and STR 2000 mg/L. The HLR to GEN and STR was detected in 13.5% and 16.3% of the isolates respectively. Among 141 strains, 7.8% were simultaneously resistant to GEN and STR. With 120-μg GEN and 300-μg STR disks, strains for which MICs were ≥ 512 mg/L and ≥ 1024 mg/L had no zones of inhibition. Isolates with inhibitory zones for GEN and STR of ≥13 mm showed a MICs ≤ 64 mg/L and ≤ 512 mg/L. All the screening plates were negative for these isolates. HLR to aminoglycosides was associated (83.9%) with resistance to erythromycin and/or clindamycin. This study highlights the emergence of strains with HLR to aminoglycosides. The disk-agar diffusion test performed with high-content aminoglycoside disks and screening plates can provide laboratories with a convenient and reliable method for detecting S. agalactiae isolates that are resistant to aminoglycoside-betalactam synergy.

  4. Two Novel Antibiotic Resistance Genes, tet(44) and ant(6)-Ib, Are Located within a Transferable Pathogenicity Island in Campylobacter fetus subsp. fetus▿

    Science.gov (United States)

    Abril, Carlos; Brodard, Isabelle; Perreten, Vincent

    2010-01-01

    New tetracycline and streptomycin resistance genes, tet(44) and ant(6)-Ib, were identified in Campylobacter fetus subsp. fetus within a transferable pathogenicity island that is typically unique to Campylobacter fetus subsp. venerealis. The 640-amino-acid tetracycline resistance determinant, Tet 44, belongs to a class of proteins that confers resistance to tetracycline and minocycline by ribosomal protection. The 286-amino-acid streptomycin resistance determinant, ANT(6)-Ib, belongs to a family of aminoglycoside nucleotidyltransferases. The resistance phenotypes were demonstrated by gene inactivation and expression. PMID:20479200

  5. Effect of streptomycin treatment on bacterial community structure in the apple phyllosphere.

    Directory of Open Access Journals (Sweden)

    Erika Yashiro

    Full Text Available We studied the effect of many years of streptomycin use in apple orchards on the proportion of phyllosphere bacteria resistant to streptomycin and bacterial community structure. Leaf samples were collected during early July through early September from four orchards that had been sprayed with streptomycin during spring of most years for at least 10 years and four orchards that had not been sprayed. The percentage of cultured phyllosphere bacteria resistant to streptomycin at non-sprayed orchards (mean of 65% was greater than at sprayed orchards (mean of 50% (P = 0.0271. For each orchard, a 16S rRNA gene clone library was constructed from leaf samples. Proteobacteria dominated the bacterial communities at all orchards, accounting for 71 of 104 OTUs (determined at 97% sequence similarity and 93% of all sequences. The genera Massilia, Methylobacterium, Pantoea, Pseudomonas, and Sphingomonas were shared across all sites. Shannon and Simpson's diversity indices and Pielou's evenness index were similar among orchards regardless of streptomycin use. Analysis of Similarity (ANOSIM indicated that long-term streptomycin treatment did not account for the observed variability in community structure among orchards (R = -0.104, P = 0.655. Other variables, including time of summer, temperature and time at sampling, and relative distance of the orchards from each other, also had no significant effect on bacterial community structure. We conclude that factors other than streptomycin exposure drive both the proportion of streptomycin-resistant bacteria and phylogenetic makeup of bacterial communities in the apple phyllosphere in middle to late summer.

  6. Effect of streptomycin treatment on bacterial community structure in the apple phyllosphere.

    Science.gov (United States)

    Yashiro, Erika; McManus, Patricia S

    2012-01-01

    We studied the effect of many years of streptomycin use in apple orchards on the proportion of phyllosphere bacteria resistant to streptomycin and bacterial community structure. Leaf samples were collected during early July through early September from four orchards that had been sprayed with streptomycin during spring of most years for at least 10 years and four orchards that had not been sprayed. The percentage of cultured phyllosphere bacteria resistant to streptomycin at non-sprayed orchards (mean of 65%) was greater than at sprayed orchards (mean of 50%) (P = 0.0271). For each orchard, a 16S rRNA gene clone library was constructed from leaf samples. Proteobacteria dominated the bacterial communities at all orchards, accounting for 71 of 104 OTUs (determined at 97% sequence similarity) and 93% of all sequences. The genera Massilia, Methylobacterium, Pantoea, Pseudomonas, and Sphingomonas were shared across all sites. Shannon and Simpson's diversity indices and Pielou's evenness index were similar among orchards regardless of streptomycin use. Analysis of Similarity (ANOSIM) indicated that long-term streptomycin treatment did not account for the observed variability in community structure among orchards (R = -0.104, P = 0.655). Other variables, including time of summer, temperature and time at sampling, and relative distance of the orchards from each other, also had no significant effect on bacterial community structure. We conclude that factors other than streptomycin exposure drive both the proportion of streptomycin-resistant bacteria and phylogenetic makeup of bacterial communities in the apple phyllosphere in middle to late summer.

  7. Streptomycin-induced inflammation enhances Escherichia coli gut colonization through nitrate respiration.

    Science.gov (United States)

    Spees, Alanna M; Wangdi, Tamding; Lopez, Christopher A; Kingsbury, Dawn D; Xavier, Mariana N; Winter, Sebastian E; Tsolis, Renée M; Bäumler, Andreas J

    2013-07-02

    Treatment with streptomycin enhances the growth of human commensal Escherichia coli isolates in the mouse intestine, suggesting that the resident microbial community (microbiota) can inhibit the growth of invading microbes, a phenomenon known as "colonization resistance." However, the precise mechanisms by which streptomycin treatment lowers colonization resistance remain obscure. Here we show that streptomycin treatment rendered mice more susceptible to the development of chemically induced colitis, raising the possibility that the antibiotic might lower colonization resistance by changing mucosal immune responses rather than by preventing microbe-microbe interactions. Investigation of the underlying mechanism revealed a mild inflammatory infiltrate in the cecal mucosa of streptomycin-treated mice, which was accompanied by elevated expression of Nos2, the gene that encodes inducible nitric oxide synthase. In turn, this inflammatory response enhanced the luminal growth of E. coli by nitrate respiration in a Nos2-dependent fashion. These data identify low-level intestinal inflammation as one of the factors responsible for the loss of resistance to E. coli colonization after streptomycin treatment. Our intestine is host to a complex microbial community that confers benefits by educating the immune system and providing niche protection. Perturbation of intestinal communities by streptomycin treatment lowers "colonization resistance" through unknown mechanisms. Here we show that streptomycin increases the inflammatory tone of the intestinal mucosa, thereby making the bowel more susceptible to dextran sulfate sodium treatment and boosting the Nos2-dependent growth of commensal Escherichia coli by nitrate respiration. These data point to the generation of alternative electron acceptors as a by-product of the inflammatory host response as an important factor responsible for lowering resistance to colonization by facultative anaerobic bacteria such as E. coli.

  8. Analysis of Aminoglycoside Modifying Enzyme Genes Responsible for High-Level Aminoglycoside Resistance among Enterococcal Isolates

    Directory of Open Access Journals (Sweden)

    Vishal Shete

    2017-01-01

    Full Text Available Enzymatic modification results in high-level resistance to aminoglycoside (HLAR, which eliminates the synergistic bactericidal effect of combined exposure to a cell wall-active agent and an aminoglycoside. So aim of the study was to determine prevalence of HLAR enterococcal isolate and to study distribution of aminoglycoside modifying enzyme genes in them. A total of 100 nonrepeat isolates of enterococci from various clinical samples were analyzed. As per Clinical and Laboratory Standards Institute guidelines enterococci were screened for HLAR by Kirby-Bauer disc diffusion method. Minimum inhibitory concentration of all isolates for gentamicin and streptomycin was determined by E-test. Multiplex polymerase chain reaction (PCR was carried out for HLAR enterococcal isolates to identify aminoglycoside modifying enzymes genes responsible for resistance. 60% isolates were found to be high-level gentamicin resistant (HLGR whereas 45% isolates were found to be high-level streptomycin resistant (HLSR. By multiplex PCR 80% HLGR isolates carried bifunctional aminoglycoside modifying enzyme gene aac(6′-Ie-aph(2′′-Ia whereas 18 out of 45 high-level streptomycin resistant, that is, 40%, isolates carried aph(3′-IIIa. However, aph(2′′-Ib, aph(2′′-Ic, aph(2′′-Id, and ant(4′-Ia genes which encode other aminoglycosides modifying enzymes were not detected. Bifunctional aminoglycoside modifying enzyme gene aac(6′-Ie-aph(2′′-Ia is the predominant gene responsible for HLAR.

  9. Completion of the nucleotide sequence of the central region of Tn5 confirms the presence of three resistance genes.

    OpenAIRE

    Mazodier, P; Cossart, P; Giraud, E; Gasser, F

    1985-01-01

    The DNA sequence of the region located downstream from the kanamycin resistance gene of Tn5 up to the right inverted repeat IS50R has been determined. This completes the determination of the sequence of Tn5 which is 5818 bp long. The 2.7 Kb central region contains three resistance genes: the kanamycin-neomycin resistance gene, a gene coding for resistance to CL990 an antimitotic-antibiotic compound of the bleomycin family and a third gene that confers streptomycin resistance in some bacterial...

  10. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

    DEFF Research Database (Denmark)

    Adelowo, Olawale O.; Fagade, Obasola E.; Agersø, Yvonne

    2014-01-01

    Introduction: This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Methodology: Minimum inhibitory concentration (MIC) distributions of the isolates were determined using...... the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. Results: A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resistance was: tetracycline 81%, sulphamethoxazole 67%, streptomycin 56%, trimethoprim 47 %, ciprofloxacin 42......%, ampicillin 36%, spectinomycin 28%, nalidixic acid 25%, chloramphenicol 22%, neomycin 14%, gentamicin 8%, amoxicillin-clavulanate, ceftiofur, cefotaxime, colistin, florfenicol and apramycin 0%. Resistance genes found among the isolates include bla-TEM (85%), sul2 (67%), sul3 (17%), aadA (65%), strA (70%), str...

  11. In-house, simple & economical phage technique for rapid detection of rifampicin, isoniazid, ethambutol, streptomycin & ciprofloxacin drug resistance using Mycobacterium tuberculosis isolates.

    Science.gov (United States)

    Hemvani, Nanda; Patidar, Vikas; Chitnis, D S

    2012-05-01

    Multiple drug resistance (MDR) among Mycobacterium tuberculosis poses a serious therapeutic problem. Early detection of MDR can be valuable but the conventional drug susceptibility tests take 4-6 wk time after the laboratory isolation of M. tuberculosis. The bacterial phage assay has been reported as a rapid tool for rifampicin susceptibility testing of tubercle bacilli using the suspension of isolated cultures. The present study was aimed to set up a phage assay for testing drug susceptibility to isoniazid (INH), rifampicin, ethambutol, streptomycin and ciprofloxacin in M. tuberculosis isolates. Mueller-Hinton broth instead of Middle Brook 7H9 broth was used to make it more economical. The phage assay was compared with the proportion method using 100 M. tuberculosis isolates from pulmonery TB cases. Phage assay results were available in 48 h for rifampicin and streptomycin while 72 h required for INH, ethambutol and ciprofloxacin. The assay was compared with gold standard proportion method. Interpretation of the results was easy and clear. In the present study, sensitivity and specificity of the phage assay when compared to proportion method were in the range of 97 to 100 per cent for all the drugs except for ciprofloxacin for which it was 93 and 96 per cent, respectively. The phage assay was economic, easy to perform and rapid for the detection of drug resistance in M. tuberculosis isolates with no requirement of expensive equipment. It is within the reach of microbiology laboratories in developing countries having high loads of tuberculosis.

  12. Chloroplast genes in Chlamydomonas affecting organelle ribosomes. Genetic and biochemical analysis of analysis of antibiotic-resistant mutants at several gene loci.

    Science.gov (United States)

    Conde, M F; Boynton, J E; Gillham, N W; Harris, E H; Tingle, C L; Wang, W L

    1975-10-03

    Six chloroplast gene mutants of Chlamydomonas reinhardtii resistant to spectinomycin, erythromycin, or streptomycin have been assessed for antibiotic resistance of their chloroplast ribosomes. Four of these mutations clearly confer high levels of antibiotic resistance on the chloroplast ribosomes both in vivo. Although one mutant resistant to streptomycin and one resistant to spectinomycin have chloroplast ribosomes as sensitive to antibiotics as those of wild type in vivo, these mutations can be shown to alter the wildtype sensitivity of chloroplast ribosomes in polynucleotide-directed amino acid incorporation in vitro. Genetic analysis of these six chloroplast mutants and three similar mutants (Sager, 1972), two of which have been shown to affect chloroplast ribosomes (Mets and Bogorad, 1972; Schlanger and Sager, 1974), indicates that in Chlamydomonas at least three chloroplast gene loci can affect streptomycin resistance of chloroplast ribosomes and that two can affect erythromycin resistance. The three spectinomycin-resistant mutants examined appear to be alleles at a single chloroplast gene locus, but may represent mutations at two different sites within the same gene. Unlike wild type, the streptomycin and spectinomycin resistant mutants which have chloroplast ribosomes sensitive to antibiotics in vivo, grow well in the presence of antibiotic by respiring exogenously supplied acetate as a carbon source, and have normal levels of cytochrome oxidase activity and cyanide-sensitive respiration. We conclude that mitochondrial protein synthesis in these mutants is resistant to these antibiotics, whereas in wild type it is sensitive. To explain the behavior of these two chloroplast gene mutants as well as other one-step mutants which are resistant both photosynthetically and when respiring acetate in the dark, we have postulated that a mutation in a single chloroplast gene may result in alteration of both chloroplast and mitochondrial ribosomes. Mitochondrial

  13. The streptomycin-sulfadiazine-tetracycline antimicrobial resistance element of calf-adapted Escherichia coli is widely distributed among isolates from Washington state cattle.

    Science.gov (United States)

    Khachatryan, Artashes R; Besser, Thomas E; Call, Douglas R

    2008-01-01

    Association of specific antimicrobial resistance patterns with unrelated selective traits has long been implicated in the maintenance of antimicrobial resistance in a population. Previously we demonstrated that Escherichia coli strains with a specific resistance pattern (resistant to streptomycin, sulfadiazine, and tetracycline [SSuT]) have a selective advantage in dairy calf intestinal environments and in the presence of a milk supplement commonly fed to the calves. In the present study we identified the sequence of the genetic element that confers the SSuT phenotype and show that this element is present in a genetically diverse group of E. coli isolates, as assessed by macrorestriction digestion and pulsed-field gel electrophoresis. This element was also found in E. coli isolates from 18 different cattle farms in Washington State. Using in vitro competition experiments we further demonstrated that SSuT strains from 17 of 18 farms were able to outcompete pansusceptible strains. In a separate set of experiments, we were able to transfer the antimicrobial resistance phenotype by electroporation to a laboratory strain of E. coli (DH10B), making that new strain more competitive during in vitro competition with the parental DH10B strain. These data indicate that a relatively large genetic element conferring the SSuT phenotype is widely distributed in E. coli from cattle in Washington State. Furthermore, our results indicate that this element is responsible for maintenance of these traits owing to linkage to genetic traits that confer a selective advantage in the intestinal lumens of dairy calves.

  14. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria.

    Science.gov (United States)

    Adelowo, Olawale O; Fagade, Obasola E; Agersø, Yvonne

    2014-09-12

    This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resistance was: tetracycline 81%, sulphamethoxazole 67%, streptomycin 56%, trimethoprim 47 %, ciprofloxacin 42%, ampicillin 36%, spectinomycin 28%, nalidixic acid 25%, chloramphenicol 22%, neomycin 14%, gentamicin 8%, amoxicillin-clavulanate, ceftiofur, cefotaxime, colistin, florfenicol and apramycin 0%. Resistance genes found among the isolates include bla-TEM (85%), sul2 (67%), sul3 (17%), aadA (65%), strA (70%), strB (61%), catA1 (25%), cmlA1 (13%), tetA (21%) and tetB (17%). Class 1 and 2 integrons were found in five (14%) and six (17%) isolates, respectively, while one isolate was positive for both classes of integrons. Seven out of eight isolates with resistance to ciprofloxacin and MIC ≤ 32 mg/L to nalidixic acid contained qnrS genes. Our findings provided additional evidence that the poultry production environment in Nigeria represents an important reservoir of antibiotic resistance genes such as qnrS that may spread from livestock production farms to human populations via manure and water.

  15. [The structure of replication initiation region of Pseudomonas IncP-7 streptomycin resistance plasmid Rms148].

    Science.gov (United States)

    Volkova, O V; Kosheleva, I A; Boronin, A M

    2012-01-01

    Pseudomonads' IncP-7 plasmids make significant contribution to the environmental biodegradative potential and sometimes harbour antibiotic resistance genes. More than 30 years plasmid Rms148 is used as archetypal P-7 plasmid in microbiological incompatibility tests. However, the structure of its basic replicon was not described up to now, as well as phylogenetic relationships between all known plasmids within the IncP-7 group were not studied. In the frames of this work we have constructed two primer pairs to amplify main components of P-7 replication initiation region, and subsequent screening of repA intragenic polymorphism was made using laboratory collection of IncP-7 plasmids. Minimal replicon of Rms148 was constructed and its nucleotide sequence was determined to be identical to repA-oriVof known P-7 plasmids on 81-83% and forming separate branch on appropriate phylogenetic tree. Additionally, repA seems to be more conservative between group members compared with putative oriV region. Deduced amino acid sequence and predicted secondary and tertiary structures of Rms148 RepA protein allow us to make assumption about similar to unclassified cryptic plasmid pPS10 model of replication initiation for IncP-7 group members.

  16. Resistance to tetracycline and multidrug resistance in resident E. coli, risk for the public health

    OpenAIRE

    Urumova, Valentina

    2015-01-01

    The most important resistant profiles in indicator E. coli isolated from swine are resistance to sulfonamides/tetracycline, ampicillin/streptomycin/sulfonamides/tetracycline. The selection pressure of tetracycline, beta-lactams and streptomycin in farm animals especially in pig farms induced co-selection to other chemotherapeutic agents and horizontal transfer of resistance is a serious risk for the dissemination of resistant genes in E. coli isolated from farm animals. The common genes li...

  17. Increased transmission of Mycobacterium tuberculosis Beijing genotype strains associated with resistance to streptomycin: a population-based study.

    NARCIS (Netherlands)

    Buu, T.N.; Soolingen, D. van; Huyen, M.N.; Lan, N.T.; Quy, H.T.; Tiemersma, E.W.; Kremer, K.; Borgdorff, M.W.; Cobelens, F.G.

    2012-01-01

    BACKGROUND: Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains.

  18. Increased Transmission of Mycobacterium tuberculosis Beijing Genotype Strains Associated with Resistance to Streptomycin: A Population-Based Study

    NARCIS (Netherlands)

    Buu, Tran N.; van Soolingen, Dick; Huyen, Mai N. T.; Lan, Nguyen T. N.; Quy, Hoang T.; Tiemersma, Edine W.; Kremer, Kristin; Borgdorff, Martien W.; Cobelens, Frank G. J.

    2012-01-01

    Background: Studies have shown that the Mycobacterium tuberculosis Beijing genotype is an emerging pathogen that is frequently associated with drug resistance. This suggests that drug resistant Beijing strains have a relatively high transmission fitness compared to other drug-resistant strains.

  19. Streptomycin induced protein expression analysis in Mycobacterium tuberculosis by two-dimensional gel electrophoresis & mass spectrometry.

    Science.gov (United States)

    Sharma, Prashant; Kumar, Bhavnesh; Singhal, Neelja; Katoch, Vishwa Mohan; Venkatesan, Krishnamurthy; Chauhan, Devendra Singh; Bisht, Deepa

    2010-10-01

    The resistance of Mycobacterium tuberculosis to streptomycin, a core drug for treatment of category II tuberculosis (TB) has posed a major challenge to the health providers as well as research workers worldwide and has severely compromised the therapeutic options. A significant proportion of streptomycin resistant M. tuberculosis isolates failed to show mutations in conventional targets like rpsL and rrs. Although efflux, permeability, etc. are also known to contribute, yet a substantial proportion of isolates remains resistant suggesting involvement of other unknown mechanism. A resistant isolate may show altered gene as well as protein expression under drug induced conditions and a whole cell proteome analysis under induced conditions might help in further understanding the mechanisms of drug resistance. The present study was therefore designed with the objective to identify proteins related to streptomycin resistance in M. tuberculosis isolate grown in presence and absence of streptomycin (SM). A clinical isolate of M. tuberculosis from Mycobacterial Repository Centre at the Institute (NJIL & OMD), Agra was grown in Sauton's medium for 36 h with/without subinhibitory concentration of the drug (2 μg/ml) and the cell lysate of isolates was prepared by sonication and centrifugation. Two-dimensional (2D) gel electrophoresis was employed to study the protein profile. The selected proteins were finally identified by MALDI-TOF mass spectrometry. Our study revealed eight inducible proteins (DnaK, fabG4, DNA-binding, hypothetical, two 14 kDa antigen and two 10 kDa chaperonin) that were upregulated in the presence of drug. This preliminary study has thrown light on whether or not and how the resistant isolate responds to streptomycin at its non-toxic but sub-inhibitory concentration. An in-depth study of the upregulated proteins will give an insight into probable sites of drug action other than established primary sites.

  20. The Attachment Site of Streptomycin to the 30S Ribosomal Subunit

    Science.gov (United States)

    Biswas, Debajit K.; Gorini, Luigi

    1972-01-01

    The 16S RNA dissociated from 30S ribosomal subunits of Escherichia coli strains either sensitive or resistant to streptomycin contains the attachment sites for two streptomycin molecules, as does the undissociated particle from a streptomycin-sensitive strain. Since no streptomycin binds to undissociated 30S subunits from a streptomycin-resistant strain, it is suggested that protein P10, specified by the strA locus—known to be responsible for drug sensitivity—controls the availability to streptomycin of the attachment sites. These sites remain exposed in the strA+ wild-type, and become masked in strA streptomycin-resistant mutants. The 16S RNA molecule binds streptomycin specifically; it binds two drug molecules in its native state, binds many more after its secondary structure is unfolded by melting out, and again binds two molecules after reannealing. The binding is stable to exhaustive dialysis, but it is reversed by exposure of the streptomycin-RNA complex to high-salt concentration. The complex can not be used to reconstitute functional ribosomes, but the 16S RNA reacquires this property after streptomycin elimination. The biological significance of this stable streptomycin binding is questioned, since in strA mutants exhibiting phenotypic masking, exposure to streptomycin induces a modified 30S behavior that persists even after streptomycin has been dialyzed away, and is reversed only by exposure of the modified RNA to high-salt concentration. PMID:4559597

  1. The evolution of no-cost resistance at sub-MIC concentrations of streptomycin in Streptomyces coelicolor

    NARCIS (Netherlands)

    Westhoff, Sanne; van Leeuwe, Tim Marijn; Qachach, Omar; Zhang, Zheren; van Wezel, G.P.; Rozen, Daniel E.

    At the high concentrations used in medicine, antibiotics exert strong selection on bacterial populations for the evolution of resistance. However, these lethal concentrations may not be representative of the concentrations bacteria face in soil, a recognition that has led to questions of the role of

  2. Use of a nonmedicated dietary supplement correlates with increased prevalence of streptomycin-sulfa-tetracycline-resistant Escherichia coli on a dairy farm.

    Science.gov (United States)

    Khachatryan, Artashes R; Besser, Thomas E; Hancock, Dale D; Call, Douglas R

    2006-07-01

    We examined how a dietary supplement affects the prevalence of antibiotic-resistant Escherichia coli on a dairy farm in Washington State. Between 2001 and 2004 the prevalence of fecal E. coli strains resistant to streptomycin, sulfadiazine, and tetracycline (SSuT strains) declined from 59.2% to 26.1% in the calf population. In 2003 the dairy discontinued use of a dietary supplement, and we hypothesized that the decline in prevalence of SSuT strains was related to this change in management. To test this we established three treatments in which calves received no supplement, the dietary supplement with oxytetracycline, or the dietary supplement without oxytetracycline. Calves receiving either dietary supplement had a significantly higher prevalence of SSuT E. coli than the no-supplement control group (approximately 37% versus 20%, respectively; P = 0.03). Importantly, there was no evidence that oxytetracycline contributed to an increased prevalence of fecal SSuT E. coli. We compared the growth characteristics of SSuT and non-SSuT E. coli in LB broth enriched with either the complete dietary supplement or its individual constituents. Both the complete dietary supplement and its vitamin D component supported a significantly higher cell density of SSuT strains (P = 0.003 and P = 0.001, respectively). The dry milk and vitamin A components of the dietary supplement did not support different cell densities. These results were consistent with selection and maintenance of SSuT E. coli due to environmental components independent of antibiotic selection.

  3. Fluorescence studies on a streptomycin-induced conformational change in ribosomes which correlates with misreading.

    Science.gov (United States)

    Hanas, J S; Simpson, M V

    1986-05-25

    The fluorescent reagent N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulfonic acid (I-AEDANS) was employed to detect and study the previously reported conformational change in the Escherichia coli ribosome induced by streptomycin. Labeling of ribosomes with this probe, which results in the derivatization of proteins S18 and L31', described earlier, inhibits neither their ribosomal protein synthesizing nor misreading ability. To calculate the amount of streptomycin bound to the ribosome, we determined the K'D for streptomycin, which is 0.24 micron, indicating that under our conditions, bound streptomycin/ribosome molar ratios are low, not in excess of 1. Under these conditions, streptomycin addition induces fluorescence quenching by 15% but does not affect streptomycin-resistant ribosomes. Maximal misreading occurs at these same ratios. Removal of AEDANS-L31' from the ribosomes drastically reduces streptomycin-induced quenching indicating the involvement of the environment of this protein in streptomycin action. The finding that streptomycin decreases AEDANS-L31' affinity for the ribosome supports this view. Streptomycin has been shown to bind to the 30 S subunit protein S4 while the 50 S protein L31' has been shown to be localized at the subunit interface. Thus, the observation that streptomycin influences this 50 S subunit protein L31', combined with the tight correlation between the effects of streptomycin on quenching and on misreading, strongly suggests that this antibiotic induces a conformational change at the subunit interface of the ribosome, and that this results in misreading. Polyuridylic acid also induces a conformational change in the ribosome but the polynucleotide and streptomycin seem to act independently. Streptomycin-resistant ribosomes, which undergo neither streptomycin-induced fluorescence nor streptomycin-induced misreading, are resistant to misreading induced by high Mg2+ as well.

  4. The chloroplast gene encoding ribosomal protein S4 in Chlamydomonas reinhardtii spans an inverted repeat--unique sequence junction and can be mutated to suppress a streptomycin dependence mutation in ribosomal protein S12.

    Science.gov (United States)

    Randolph-Anderson, B L; Boynton, J E; Gillham, N W; Huang, C; Liu, X Q

    1995-05-10

    The ribosomal protein gene rps4 was cloned and sequenced from the chloroplast genome of Chlamydomonas reinhardtii. The N-terminal 213 amino acid residues of the S4 protein are encoded in the single-copy region (SCR) of the genome, while the C-terminal 44 amino acid residues are encoded in the inverted repeat (IR). The deduced 257 amino acid sequence of C. reinhardtii S4 is considerably longer (by 51-59 residues) than S4 proteins of other photosynthetic species and Escherichia coli, due to the presence of two internal insertions and a C-terminal extension. A short conserved C-terminal motif found in all other S4 proteins examined is missing from the C. reinhardtii protein. In E. coli, mutations in the S4 protein suppress the streptomycin-dependent (sd) phenotype of mutations in the S12 protein. Because we have been unable to identify similar S4 mutations among suppressors of an sd mutation in C. reinhardtii S12 obtained using UV mutagenesis, we made site-directed mutations [Arg68 (CGT) to Leu (CTG and CTT)] in the wild-type rps4 gene equivalent to an E. coli Gln53 to Leu ribosomal ambiguity mutation (ram), which suppresses the sd phenotype and decreases translational accuracy. These mutants were tested for their ability to transform the sd S12 mutation of C. reinhardtii to streptomycin independence. The streptomycin-independent isolates obtained by biolistic transformation all possessed the original sd mutation in rps12, but none had the expected donor Leu68 mutations in rps4. Instead, six of 15 contained a Gln73 (CAA) to Pro (CCA) mutation five amino acids downstream from the predicted mutant codon, irrespective of rps4 donor DNA. Two others contained six- and ten-amino acid, in-frame insertions at S4 positions 90 and 92 that appear to have been induced by the biolistic process itself. Eight streptomycin-independent isolates analyzed had wild-type rps4 genes and may possess mutations identical to previously isolated suppressors of sd that define at least two

  5. Mistranslation and genetic variability: the effect of streptomycin.

    Science.gov (United States)

    Nagel, Rosa; Chan, Ana

    2006-10-10

    Streptomycin is an aminoglycoside antibiotic that acts at the level of protein synthesis. Exposure to sublethal concentrations of this antibiotic increased significantly the number of Arg+ mutants derived from an Escherichia coli argE3 (ochre) rpsL31 (streptomycin-resistant) strain. The vast majority of these mutants appeared on selective minimal medium plates with streptomycin (200 micro g/ml) during stationary phase, after 6-10 days incubation at 37 degrees C. Derivative mutD5 or mutL or mutS mutants, carrying a faulty epsilon subunit of DNA polymerase or a defective mismatch DNA-repair protein, respectively, also showed higher numbers of Arg+ mutants on selective medium with streptomycin than on medium without streptomycin. Interestingly, with these DNA-repair mutants about 50% of the Arg+ mutants generated in the presence of streptomycin appeared during the first 5 days of incubation. These observations suggest that the activities of these fidelity-repair proteins prevent in the parental strain the early appearance of the supernumerary Arg+ mutants on the selective medium with streptomycin. The appearance of Arg+ mutants on the plates with streptomycin was not significantly altered by recA, rpoS or dps mutations. A high percentage of the Arg+ mutants arising in the presence of streptomycin were streptomycin-dependent for growth without arginine (Arg+ St-D). These types of mutants displayed a Ram (for ribosomal ambiguity) phenotype, manifested by increased misreading, assayed by in vitro and in vivo experiments and by leakiness on several selective minimal media. Genetic data indicated that these mutants carry a mutation located at about 74 min of the E.coli map that relieves the high translational fidelity conferred by the rpsL mutation. These studies suggest that the growth-limiting conditions of the assay system used, as well as the presence of streptomycin, which causes an increased production of altered proteins, favours the appearance and growth of

  6. Using whole-genome sequencing to determine appropriate streptomycin epidemiological cutoffs for Salmonella and Escherichia coli.

    Science.gov (United States)

    Tyson, Gregory H; Li, Cong; Ayers, Sherry; McDermott, Patrick F; Zhao, Shaohua

    2016-02-01

    For Enterobacteriaceae such as Salmonella spp. and Escherichia coli, no unified interpretive resistance criteria exist for streptomycin, an epidemiologically important antibiotic. As part of the National Antimicrobial Resistance Monitoring System, we had previously used a minimum inhibitory concentration of ≥ 64 μg mL(-1) as an epidemiological cutoff value (ECV) to define non-wild-type isolates. To identify whether this ECV correlated with genetic determinants of resistance, we performed whole-genome sequencing of 463 Salmonella and E. coli isolates to identify streptomycin resistance genotypes. From this analysis, we found that using a streptomycin resistance breakpoint of ≥ 64 μg mL(-1) classified over 20% of strains possessing aadA or strA/strB resistance genes as wild-type. Therefore, to improve the concordance between genotypic and phenotypic data, we propose reducing the phenotypic cutoff values to ≥ 32 μg mL(-1) for both Salmonella and E. coli, to be used widely as ECVs to categorize non-wild-type isolates. Published by Oxford University Press on behalf of FEMS 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  7. Ribosomal assembly influenced by growth in the presence of streptomycin.

    Science.gov (United States)

    Garvin, R T; Rosset, R; Gorini, L

    1973-10-01

    Translational leakiness (i.e., nonspecific suppression) of nonsense mutants of bacteriophage T4 is increased in cells of certain streptomycin-resistant strains previously grown in the presence of streptomycin. Concomitantly, ribosomes extracted from these streptomycin-grown cells possess a high level of misreading. Increased suppression ability as well as ribosomes that highly misread accumulate with kinetics expected for a constant differential rate of synthesis of a new product induced by drug action. The misreading ribosomes do not contain appreciable amounts of streptomycin and the misreading property is lost by exposure to high salt concentrations. It is suggested that streptomycin (or dihydrostreptomycin, or paromomycin) induces a reversible modification in 30S subunit assembly without physically participating in the modified structure. The extent of this modification appears dependent upon the strA allele.

  8. Combined treatment with the antibiotics kanamycin and streptomycin promotes the conjugation of Escherichia coli.

    Science.gov (United States)

    Zhang, Peng-Yi; Xu, Pei-Pei; Xia, Zhi-Jie; Wang, Jing; Xiong, Juan; Li, Yue-Zhong

    2013-11-01

    It is widely accepted that antibiotics provide a critical selective pressure for the horizontal transfer of antibiotic resistance between bacterial species. This study demonstrated that a combination of low doses of kanamycin and streptomycin, which inhibited the growth of recipient and donor cells, respectively, had positive effects on the transmission of the conjugation plasmids pRK2013, pSU2007, and RP4 from Escherichia coli DH5α to HB101 at their minimum inhibitory concentrations (MICs). Administration of either antibiotic alone as well as other antibiotics in combination or alone did not have this effect. Two-dimensional electrophoresis revealed that 60 proteins were downregulated and 14 proteins were upregulated in the conjugation of E. coli DH5α (pRK2013) and HB101 in the presence of kanamycin and streptomycin. Of these proteins, 64 were subsequently identified by mass spectrometry. Two antibiotic-induced genes encoding oligopeptide-binding protein (OppA) and ribose-binding protein (RbsB) were further confirmed by quantitative real-time PCR. When these genes were deleted, the number of transconjugants decreased in the same fashion as when the cells were treated with kanamycin and streptomycin. These results indicate that the process of E. coli conjugation may be promoted by combination treatment with kanamycin and streptomycin and that two proteins potentially participated in this process. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  9. Interaction between rpsL and gyrA mutations affects the fitness and dual resistance of Mycobacterium tuberculosis clinical isolates against streptomycin and fluoroquinolones

    Directory of Open Access Journals (Sweden)

    Sun H

    2018-03-01

    Full Text Available Honghu Sun,1,2,* Jumei Zeng,3,* Song Li,1 Pengkuan Liang,1 Chao Zheng,1 Yong Liu,4 Tao Luo,5 Nalin Rastogi,6 Qun Sun,1 1Key Laboratory of Bio-Resources and Eco-Environment of the Ministry of Education, College of Life Sciences, Sichuan University, 2Chengdu Institutes for Food and Drug Control, Chengdu, Sichuan, People’s Republic of China; 3Department of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA; 4Public Health Clinical Center of Chengdu, 5West China College of Preclinical Medicine and Forensic Medicine, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 6WHO Supranational TB Reference Laboratory, Institut Pasteur de la Guadeloupe, Abymes, Guadeloupe, France *These authors contributed equally to this work Background: The interaction between different drug-resistant mutations is important to the development of drug resistance and its evolution. In this study, we aimed to reveal the potential relationships between mutations conferring resistance to two important antituberculosis drugs streptomycin (STR and fluoroquinolones (FLQ.Materials and methods: We used an in vitro competitive fitness assay to reveal the interactions between different mutations of rpsL and gyrA in drug-resistant Mycobacterium smegmatis, followed by the analysis of the frequency of rpsL and gyrA mutation combinations in 213 STR–FLQ dual-resistant clinical Mycobacterium tuberculosis isolates from Sichuan region, which was also investigated by the whole genome data from 3,056 global clinical M. tuberculosis isolates.Results: The strains with K43R and K88R mutation in rpsL showed no difference in relative fitness compared with their susceptible ancestor, while K43N, K43M, K43T, and K88E exhibited a significantly lower relative fitness (P<0.05. For the FLQ-resistant mutants, all mutation types showed no difference in their relative fitness. Among STR–FLQ dual-resistant M. smegmatis strains, a lower fitness was

  10. Anthropogenic antibiotic resistance genes mobilization to the polar regions.

    Science.gov (United States)

    Hernández, Jorge; González-Acuña, Daniel

    2016-01-01

    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.

  11. 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.

  12. Characterisation of integrons and antibiotic resistance genes in Danish multiresistant Salmonella enterica Typhimurium DT104

    DEFF Research Database (Denmark)

    Sandvang, Dorthe; Aarestrup, Frank Møller; Jensen, Lars Bogø

    1997-01-01

    The presence and genetic content of integrons was investigated in eight Salmonella enterica Typhimurium DT104 isolates from different pig herds in Denmark. Two different integrons were identified using PCR and sequencing. Each of the integrons carried a single resistance cassette in addition...... to the sul1 and qacE Delta 1 genes characteristic of integrons. The first integron encoded the ant (3 ")-Ia gene that specified resistance to spectinomycin and streptomycin. The second contained the pse-l beta-lactamase gene. All the multiresistant strains contained both integrons. The presence of these two...... integrons did not account for the total phenotypic resistance of all the isolates and does not exclude the presence of other mobile DNA elements....

  13. Characterisation of integrons and antibiotic resistance genes in Danish multiresistant Salmonella enterica Typhimurium DT104

    DEFF Research Database (Denmark)

    Sandvang, Dorthe; Aarestrup, Frank Møller; Jensen, Lars Bogø

    1998-01-01

    The presence and genetic content of integrons was investigated in eight Salmonella enteritica Typhimurium DT104 isolates from different pig herds in Denmark. Two different integrons were identified using PCR and sequencing. Each of the integrons carried a single resistance cassette in addition...... to the sul1 and qacE Delta 1 genes characteristic of integrons. The first integron encoded the ant (3")-Ia gene that specified resistance to spectinomycin and streptomycin. The second contained the pse-1 beta-lactamase gene. All the multiresistant strains contained both integrons. The presence of these two...... integrons did not account for the total phenotypic resistance of all the isolates and does not exclude the presence of other mobile DNA elements....

  14. Rapid Isolation and Molecular Detection of Streptomycin-Producing Streptomycetes

    Directory of Open Access Journals (Sweden)

    M Motovali-bashi

    2006-07-01

    Full Text Available Introduction: Streptomyces species are mycelial, aerobic gram-positive bacteria that are isolated from soil and produce a diverse range of antibiotics. Streptomyces griseus produces the antibiotic, streptomycin and forms spores even in a liquid culture. The gene cluster for the production of Streptomycin antibiotic contains strR gene that encodes StrR, a pathway-specific regulator. Then, this pathway-specific regulator induces transcription of other streptomycin production genes in the gene cluster. The overall aim of this work was rapid isolation and molecular detection of streptomycin-producing Streptomycetes, especially S. griseus, from Iranian soils in order to manipulate them for increased production of streptomycin. Methods: This research used new initiative half-specific medium for isolation of Streptomycetes from natural environments, called FZmsn. The fifty colonies of Streptomyces strains grown on the surface of FZmsn medium isolated from environmental samples were defined on the basis of their morphological characteristics and light microscope studies. A set of primers was designed to detect strR by OLIGO software. Results: In colony-PCR reactions followed by gel electrophoresis, 6 colonies from Streptomyces strains colonies were detected as S. griseus colonies. Conclusion: These native Streptomyces strains will be used for genetic manipulation of S. griseus in order to increase production levels of streptomycin.

  15. A simple and economical in-house phage technique for the rapid detection of rifampin, isoniazid, ethambutol, streptomycin, and ciprofloxacin drug resistance in Mycobacterium tuberculosis, directly on decontaminated sputum samples.

    Science.gov (United States)

    Hemvani, Nanda; Patidar, Vikas; Chitnis, D S

    2012-05-01

    The early detection of drug resistance would be a boon for TB control programs. The aim of the present study was to set up a rapid phage assay for the testing of drug susceptibility of Mycobacterium tuberculosis to rifampin, isoniazid, ethambutol, streptomycin, and ciprofloxacin, directly on decontaminated sputum samples. Mueller-Hinton broth was used instead of 7H9 broth to make the method more economical. Vancomycin and polymyxin B were added to the concentrated sputum samples to reduce the bacterial contamination. The phage assay on decontaminated sputum samples was compared with the proportion method using M. tuberculosis isolates from the same sputum samples. Phage assay results were available within 48h for rifampin and streptomycin and within 72h for all the other drugs. In contrast the proportion method required 4-6 weeks from the primary cultures. The sensitivity of the phage assay was in the range of 93% to 100% and specificity in the range of 96% to 100% for all the drugs tested. The interpretation of results was possible for 334 of the 370 (90.3%) acid-fast bacillus (AFB) smear-positive sputum samples by the phage assay. The phage assay for the detection of drug resistance on direct decontaminated sputum samples is economical, easy to perform, and rapid. Copyright © 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  16. Obesity genes and insulin resistance.

    Science.gov (United States)

    Belkina, Anna C; Denis, Gerald V

    2010-10-01

    The exploding prevalence of insulin resistance and Type 2 diabetes (T2D) linked to obesity has become an alarming public health concern. Worldwide, approximately 171 million people suffer from obesity-induced diabetes and public health authorities expect this situation to deteriorate rapidly. An interesting clinical population of 'metabolically healthy but obese' (MHO) cases is relatively protected from T2D and its associated cardiovascular risk. The molecular basis for this protection is not well understood but is likely to involve reduced inflammatory responses. The inflammatory cells and pathways that respond to overnutrition are the primary subject matter for this review. The chance discovery of a genetic mutation in the Brd2 gene, which is located in the class II major histocompatibility complex and makes mice enormously fat but protects them from diabetes, offers revolutionary new insights into the cellular mechanisms that link obesity to insulin resistance and T2D. These Brd2-hypomorphic mice have reduced inflammation in fat that is normally associated with insulin resistance, and resemble MHO patients, suggesting novel therapeutic pathways for obese patients at risk for T2D. Deeper understanding of the functional links between genes that control inflammatory responses to diet-induced obesity is crucial to the development of therapies for obese, insulin-resistant patients.

  17. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature.

    Science.gov (United States)

    Singh, Atul K; Drolia, Rishi; Bai, Xingjian; Bhunia, Arun K

    2015-01-01

    We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125-250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25-5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25-50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods.

  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. Purification and Characterization of Aminoglycoside Phosphotransferase APH(6)-Id, a Streptomycin Inactivating Enzyme

    Science.gov (United States)

    Ashenafi, Meseret; Ammosova, Tatiana; Nekhai, Sergei; Byrnes, W. Malcolm

    2014-01-01

    As part of an overall project to characterize the streptomycin phosphotransferase enzyme APH(6)-Id, which confers bacterial resistance to streptomycin, we cloned, expressed, purified and characterized the enzyme. When expressed in E. coli, the recombinant enzyme increased by up to 70-fold the minimum inhibitory concentration (MIC) needed to inhibit cell growth. Size exclusion chromatography gave a molecular mass of 31.4 ± 1.3 kDa for the enzyme, showing that it functions as a monomer. Activity was assayed using three methods: (1) an HPLC-based method that measures the consumption of streptomycin over time; (2) a spectrophotometric method that utilizes a coupled assay; and (3) a radioenzymatic method that detects production of 32P-labeled streptomycin phosphate. Altogether, the three methods demonstrated that streptomycin was consumed in the APH(6)-Id-catalyzed reaction, ATP was hydrolyzed, and streptomycin phosphate was produced in a substrate-dependent manner, demonstrating that APH(6)-Id is a streptomycin phosphotransferase. Steady state kinetic analysis gave the following results: Km(streptomycin) of 0.38 ± 0.13 mM, Km(ATP) of 1.03 ± 0.1 mM, Vmax of 3.2 ± 1.1 μmol/min/mg and kcat of 1.7 ± 0.6 s−1. Our study demonstrates that APH(6)-Id is a bona fide streptomycin phosphotransferase, functions as a monomer, and confers resistance to streptomycin. PMID:24248535

  20. Purification and characterization of aminoglycoside phosphotransferase APH(6)-Id, a streptomycin-inactivating enzyme.

    Science.gov (United States)

    Ashenafi, Meseret; Ammosova, Tatiana; Nekhai, Sergei; Byrnes, W Malcolm

    2014-02-01

    As part of an overall project to characterize the streptomycin phosphotransferase enzyme APH(6)-Id, which confers bacterial resistance to streptomycin, we cloned, expressed, purified, and characterized the enzyme. When expressed in Escherichia coli, the recombinant enzyme increased by up to 70-fold the minimum inhibitory concentration needed to inhibit cell growth. Size-exclusion chromatography gave a molecular mass of 31.4 ± 1.3 kDa for the enzyme, showing that it functions as a monomer. Activity was assayed using three methods: (1) an HPLC-based method that measures the consumption of streptomycin over time; (2) a spectrophotometric method that utilizes a coupled assay; and (3) a radioenzymatic method that detects production of (32)P-labeled streptomycin phosphate. Altogether, the three methods demonstrated that streptomycin was consumed in the APH(6)-Id-catalyzed reaction, ATP was hydrolyzed, and streptomycin phosphate was produced in a substrate-dependent manner, demonstrating that APH(6)-Id is a streptomycin phosphotransferase. Steady-state kinetic analysis gave the following results: K(m)(streptomycin) of 0.38 ± 0.13 mM, K(m)(ATP) of 1.03 ± 0.1 mM, V(max) of 3.2 ± 1.1 μmol/min/mg, and k(cat) of 1.7 ± 0.6 s(-1). Our study demonstrates that APH(6)-Id is a bona fide streptomycin phosphotransferase, functions as a monomer, and confers resistance to streptomycin.

  1. Mutations in rsmG, encoding a 16S rRNA methyltransferase, result in low-level streptomycin resistance and antibiotic overproduction in Streptomyces coelicolor A3(2).

    Science.gov (United States)

    Nishimura, Kenji; Hosaka, Takeshi; Tokuyama, Shinji; Okamoto, Susumu; Ochi, Kozo

    2007-05-01

    Certain str mutations that confer high- or low-level streptomycin resistance result in the overproduction of antibiotics by Streptomyces spp. The str mutations that confer the high-level resistance occur within rpsL, which encodes the ribosomal protein S12, while those that cause low-level resistance are not as well known. We have used comparative genome sequencing to determine that low-level resistance is caused by mutations of rsmG, which encodes an S-adenosylmethionine (SAM)-dependent 16S rRNA methyltransferase containing a SAM binding motif. Deletion of rsmG from wild-type Streptomyces coelicolor resulted in the acquisition of streptomycin resistance and the overproduction of the antibiotic actinorhodin. Introduction of wild-type rsmG into the deletion mutant completely abrogated the effects of the rsmG deletion, confirming that rsmG mutation underlies the observed phenotype. Consistent with earlier work using a spontaneous rsmG mutant, the strain carrying DeltarsmG exhibited increased SAM synthetase activity, which mediated the overproduction of antibiotic. Moreover, high-performance liquid chromatography analysis showed that the DeltarsmG mutant lacked a 7-methylguanosine modification in the 16S rRNA (possibly at position G518, which corresponds to G527 of Escherichia coli). Like certain rpsL mutants, the DeltarsmG mutant exhibited enhanced protein synthetic activity during the late growth phase. Unlike rpsL mutants, however, the DeltarsmG mutant showed neither greater stability of the 70S ribosomal complex nor increased expression of ribosome recycling factor, suggesting that the mechanism underlying increased protein synthesis differs in the rsmG and the rpsL mutants. Finally, spontaneous rsmG mutations arose at a 1,000-fold-higher frequency than rpsL mutations. These findings provide new insight into the role of rRNA modification in activating secondary metabolism in Streptomyces.

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

    Science.gov (United States)

    2007-08-01

    cephalosporins and streptomycin in the 1940s was closely followed by the emergence of antibiotic resistant bacteria. The rapid increase in the number... spectrum of tetracyclines, with the exception of tet(B). Enzymatic inactivation of tetracycline: The only example described to date for inactivation of

  3. Detection of Multidrug-Resistant Salmonella enterica Serotype typhimurium DT104 Based on a Gene Which Confers Cross-Resistance to Florfenicol and Chloramphenicol

    Science.gov (United States)

    Bolton, Lance F.; Kelley, Lynda C.; Lee, Margie D.; Fedorka-Cray, Paula J.; Maurer, John J.

    1999-01-01

    Salmonella enterica serotype typhimurium (S. typhimurium) DT104 (DT104) first emerged as a major pathogen in Europe and is characterized by its pentadrug-resistant pattern. It has also been associated with outbreaks in the United States. The organism typically carries resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline. The mechanism of chloramphenicol resistance in DT104 was determined by producing antibiotic-resistant Escherichia coli host strain clones from DT104 DNA. DNA from chloramphenicol-resistant clones was sequenced, and probes specific for the genes floS. typhimurium (floSt), int, invA, and spvC were produced for colony blot hybridizations. One hundred nine Salmonella isolates, including 44 multidrug-resistant DT104 isolates, were tested to evaluate the specificities of the probes. The gene floSt, reported in this study, confers chloramphenicol and florfenicol resistance on S. typhimurium DT104. Florfenicol resistance is unique to S. typhimurium DT104 and multidrug-resistant S. typhimurium isolates with the same drug resistance profile among all isolates evaluated. Of 44 DT104 isolates tested, 98% were detected based on phenotypic florfenicol resistance and 100% had the floSt-positive genotype. Resistances to florfenicol and chloramphenicol are conferred by the gene floSt, described in this paper. Presumptive identification of S. typhimurium DT104 can be made rapidly based on the presence of the floSt gene or its resulting phenotype. PMID:10203484

  4. 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®.

  5. High Level Aminoglycoside Resistance and Distribution of Aminoglycoside Resistant Genes among Clinical Isolates of Enterococcus Species in Chennai, India

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    Elango Padmasini

    2014-01-01

    Full Text Available Enterococci are nosocomial pathogen with multiple-drug resistance by intrinsic and extrinsic mechanisms. Aminoglycosides along with cell wall inhibitors are given clinically for treating enterococcal infections. 178 enterococcal isolates were analyzed in this study. E. faecalis is identified to be the predominant Enterococcus species, along with E. faecium, E. avium, E. hirae, E. durans, E. dispar and E. gallinarum. High level aminoglycoside resistance (HLAR by MIC for gentamicin (GM, streptomycin (SM and both (GM + SM antibiotics was found to be 42.7%, 29.8%, and 21.9%, respectively. Detection of aminoglycoside modifying enzyme encoding genes (AME in enterococci was identified by multiplex PCR for aac(6′-Ie-aph(2′′-Ia; aph(2′′-Ib; aph(2′′-Ic; aph(2′′-Id and aph(3′-IIIa genes. 38.2% isolates carried aac(6′-Ie-aph(2′′-Ia gene and 40.4% isolates carried aph(3′-IIIa gene. aph(2′′-Ib; aph(2′′-Ic; aph(2′′-Id were not detected among our study isolates. aac(6′-Ie-aph(2′′-Ia and aph(3′-IIIa genes were also observed in HLAR E. durans, E. avium, E. hirae, and E. gallinarum isolates. This indicates that high level aminoglycoside resistance genes are widely disseminated among isolates of enterococci from Chennai.

  6. The role of ribosomal conformation in protein biosynthesis: the streptomycin-ribosome interaction.

    Science.gov (United States)

    Sherman, M I; Simpson, M V

    1969-12-01

    The role played by ribosomal conformation in codon-anticodon recognition has been studied using streptomycin as a probe, inasmuch as streptomycin is known to cause misreading of the genetic code. Changes in ribosomal structure have been followed by the method of hydrogen-tritium exchange. The results show that streptomycin induces two types of change in the hydrogen exchange pattern. At low molar ratios of streptomycin to ribosomes, a stimulation of the hydrogen exchange rate ("loosening" of ribosomal structure) is observed, with a small inhibition of polypeptide synthesis. As the streptomycin: ribosome ratio is increased, a maximum exchange rate is reached, after which the rate decreases ("tightening" of structure); in this region, inhibition of peptide synthesis increases sharply, and misreading of the code begins. None of these effects is observed with streptomycin-resistant ribosomes.

  7. THE ROLE OF RIBOSOMAL CONFORMATION IN PROTEIN BIOSYNTHESIS: THE STREPTOMYCIN-RIBOSOME INTERACTION*

    Science.gov (United States)

    Sherman, Michael I.; Simpson, Melvin V.

    1969-01-01

    The role played by ribosomal conformation in codon-anticodon recognition has been studied using streptomycin as a probe, inasmuch as streptomycin is known to cause misreading of the genetic code. Changes in ribosomal structure have been followed by the method of hydrogen-tritium exchange. The results show that streptomycin induces two types of change in the hydrogen exchange pattern. At low molar ratios of streptomycin to ribosomes, a stimulation of the hydrogen exchange rate (“loosening” of ribosomal structure) is observed, with a small inhibition of polypeptide synthesis. As the streptomycin: ribosome ratio is increased, a maximum exchange rate is reached, after which the rate decreases (“tightening” of structure); in this region, inhibition of peptide synthesis increases sharply, and misreading of the code begins. None of these effects is observed with streptomycin-resistant ribosomes. PMID:4916926

  8. Mutant mtDNA at 1555 A to G in 12S rRNA gene and hypersusceptibility of mitochondrial translation to streptomycin can be co-transferred to rho 0 HeLa cells.

    Science.gov (United States)

    Inoue, K; Takai, D; Soejima, A; Isobe, K; Yamasoba, T; Oka, Y; Goto, Y; Hayashi, J

    1996-06-25

    Human skin fibroblast line 95-119, which had been isolated from the mother of a Japanese patient with aminoglycoside-induced deafness and a 1555 A to G mutation at 12S rRNA gene in mitochondrial DNA (mtDNA), was used to investigate the relationship between the 1555 mtDNA mutation and its pathogenicity. By the intercellular transfer of mtDNA with or without the 1555 mutation to mtDNA-less (rho 0) HeLa cells, we isolated cybrid clones and found that the mitochondrial translation in a cybrid clone repopulated with the homoplasmic 1555 mutation showed the highest susceptibility to streptomycin. These observations suggest that the genotype of the mutant mtDNA and the phenotype of hypersusceptibility to streptomycin observed in 95-119 fibroblasts were co-transferred simultaneously to rho 0 HeLa cells, supporting the idea that the homoplasmic 1555 mtDNA mutation is involved in the pathogenesis leading to aminoglycoside-induced hearing loss.

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

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    Nelisiwe Mkize

    2017-05-01

    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

  10. 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.

  11. Streptomycin sensitivity of ribosomes isolated from a streptomycin-producing Streptomyces griseus.

    Science.gov (United States)

    Valu, G; Szabó, G

    1979-01-01

    The streptomycin sensitivity of ribosomes derived from a streptomycin-producing Streptomyces griseus was examined in a polyuridylic acid directed 14C-phenylalanine incorporating system. In order to get reproducible results it is essential to use cell-free extracts which do not inactivate streptomycin. This condition can be fulfilled by the combination of washed ribosomes of the streptomycin-producing strain and the 110 000 g supernatant of the streptomycin-nonproducing variant of S. griseus, because the streptomycin-phosphorylating activity can be washed out from ribosomes of younger streptomycin-producing cultures, and the streptomycin-nonproducing S. griseus does not have any streptomycin-inactivating capacity. In this amino acid polymerizing system the ribosomes of the streptomycin-producing strain were as sensitive to streptomycin as the ribosomes of the nonproducing variant or of Escherichia coli.

  12. Selection for Spontaneous "Escherichia coli" Streptomycin Mutants Using Basic Fuchsin.

    Science.gov (United States)

    Walkosz, Ronald

    1991-01-01

    An exercise that uses a common bacterium, E. coli, in great numbers, to detect a demonstrable change in the ability of some cells to become resistant to the common antibiotic streptomycin is presented. The procedure for preparing and pouring the gradient antibiotic plates is provided. The advantages of using the Basic Fuchsin in the agar are…

  13. Diversity of Antibiotic Resistance Genes in Enterococcus Strains Isolated from Ready-to-Eat Meat Products.

    Science.gov (United States)

    Chajęcka-Wierzchowska, Wioleta; Zadernowska, Anna; Łaniewska-Trokenheim, Łucja

    2016-10-25

    The objective of the study was to answer the question of whether the ready-to-eat meat products can pose indirect hazard for consumer health serving as reservoir of Enterococcus strains harboring tetracyclines, aminoglycosides, and macrolides resistance genes. A total of 390 samples of ready-to-eat meat products were investigated. Enterococcus strains were found in 74.1% of the samples. A total of 302 strains were classified as: Enterococcus faecalis (48.7%), Enterococcus faecium (39.7%), Enterococcus casseliflavus (4.3%), Enterococcus durans (3.0%), Enterococcus hirae (2.6%), and other Enterococcus spp. (1.7%). A high percentage of isolates were resistant to streptomycin high level (45%) followed by erythromycin (42.7%), fosfomycin (27.2%), rifampicin (19.2%), tetracycline (36.4%), tigecycline (19.9%). The ant(6')-Ia gene was the most frequently found gene (79.6%). Among the other genes that encode aminoglycosides-modifying enzymes, the highest portion of the strains had the aac(6')-Ie-aph(2'')-Ia (18.5%) and aph(3'')-IIIa (16.6%), but resistance of isolates from food is also an effect of the presence of aph(2'')-Ib, aph(2'')-Ic, aph(2'')-Id genes. Resistance to tetracyclines was associated with the presence of tetM (43.7%), tetL (32.1%), tetK (14.6%), tetW (0.7%), and tetO (0.3%) genes. The ermB and ermA genes were found in 33.8% and 18.9% of isolates, respectively. Nearly half of the isolates contained a conjugative transposon of the Tn916/Tn1545 family. Enterococci are widely present in retail ready-to-eat meat products. Many isolated strains (including such species as E. casseliflavus, E. durans, E. hirae, and Enterococcus gallinarum) are antibiotic resistant and carry transferable resistance genes. © 2016 Institute of Food Technologists®.

  14. Prevalence of antibiotic resistance genes in antibiotic-resistant Escherichia coli isolates in surface water of Taihu Lake Basin, China.

    Science.gov (United States)

    Zhang, Song He; Lv, Xiaoyang; Han, Bing; Gu, Xiucong; Wang, Pei Fang; Wang, Chao; He, Zhenli

    2015-08-01

    The rapid development of antibiotic-resistant bacteria (ARB) has been of concern worldwide. In this study, antibiotic resistance genes (ARGs) were investigated in antibiotic-resistant Escherichia coli isolated from surface water samples (rivers, n = 17; Taihu Lake, n = 16) and from human, chicken, swine, and Egretta garzetta sources in the Taihu Basin. E. coli showing resistance to at least five drugs occurred in 31, 67, 58, 27, and 18% of the isolates from surface water (n = 665), chicken (n = 27), swine (n = 29), human (n = 45), and E. garzetta (n = 15) sources, respectively. The mean multi-antibiotic resistance (MAR) index of surface water samples (0.44) was lower than that of chicken (0.64) and swine (0.57) sources but higher than that of human (0.30) and E. garzetta sources (0.15). Ten tetracycline, four sulfonamide, four quinolone, five β-lactamase, and two streptomycin resistance genes were detected in the corresponding antibiotic-resistant isolates. Most antibiotic-resistant E. coli harbored at least two similar functional ARGs. Int-I was detected in at least 57% of MAR E. coli isolates. The results of multiple correspondence analysis and Spearman correlation analysis suggest that antibiotic-resistant E. coli in water samples were mainly originated from swine, chicken, and/or human sources. Most of the ARGs detected in E. garzetta sources were prevalent in other sources. These data indicated that human activities may have contributed to the spread of ARB in the aquatic environment.

  15. Prevalence of antibiotic resistance genes in the bacterial flora of integrated fish farming environments of Pakistan and Tanzania.

    Science.gov (United States)

    Shah, Syed Q A; Colquhoun, Duncan J; Nikuli, Hamisi L; Sørum, Henning

    2012-08-21

    The use of a wide variety of antimicrobials in human and veterinary medicine, including aquaculture, has led to the emergence of antibiotic resistant pathogens. In the present study, bacteria from water, sediments, and fish were collected from fish farms in Pakistan and Tanzania with no recorded history of antibiotic use. The isolates were screened for the presence of resistance genes against various antimicrobials used in aquaculture and animal husbandry. Resistant isolates selected by disk diffusion and genotyped by Southern hybridization were further screened by polymerase chain reaction (PCR) and amplicon sequencing. The prominent resistance genes identified encoded tetracycline [tetA(A) and tetA(G)], trimethoprim [dfrA1, dfrA5, dfrA7, dfrA12, and dfrA15], amoxicillin [bla(TEM)], streptomycin [strA-strB], chloramphenicol [cat-1], and erythromycin resistance [mefA]. The int1 gene was found in more than 30% of the bacterial isolates in association with gene cassettes. MAR indices ranged from 0.2 to 1. The bla(NDM-1) gene was not identified in ertapenem resistant isolates. It is hypothesized that integrated fish farming practices utilizing domestic farm and poultry waste along with antibiotic residues from animal husbandry may have contributed to a pool of resistance genes in the aquaculture systems studied.

  16. Functional metagenomic characterization of antibiotic resistance genes in agricultural soils from China.

    Science.gov (United States)

    Su, Jian Qiang; Wei, Bei; Xu, Chun Yan; Qiao, Min; Zhu, Yong Guan

    2014-04-01

    Soil has been regarded as a rich source of antibiotic resistance genes (ARGs) due to the complex microbial community and diverse antibiotic-producing microbes in soil, however, little is known about the ARGs in unculturable bacteria. To investigate the diversity and distribution of ARGs in soil and assess the impact of agricultural practice on the ARGs, we screened soil metagenomic library constructed using DNA from four different agricultural soil for ARGs. We identified 45 clones conferring resistance to minocycline, tetracycline, streptomycin, gentamicin, kanamycin, amikacin, chloramphenicol and rifampicin. The similarity of identified ARGs with the closest protein in GenBank ranged from 26% to 92%, with more than 60% of identified ARGs had low similarity less than 60% at amino acid level. The identified ARGs include aminoglycoside acetyltransferase, aminoglycoside 6-adenyltransferase, ADP-ribosyl transferase, ribosome protection protein, transporters and other antibiotic resistant determinants. The identified ARGs from the soil with manure application account for approximately 70% of the total ARGs in this study, implying that manure amendment may increase the diversity of antibiotic resistance genes in soil bacteria. These results suggest that antibiotic resistance in soil remains unexplored and functional metagenomic approach is powerful in discovering novel ARGs and resistant mechanisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Conjugal transfer of aac(6')Ie-aph(2″)Ia gene from native species and mechanism of regulation and cross resistance in Enterococcus faecalis MCC3063 by real time-PCR.

    Science.gov (United States)

    Jaimee, G; Halami, P M

    2017-09-01

    High level aminoglycoside resistance (HLAR) in the lactic acid bacteria (LAB) derived from food animals is detrimental. The aim of this study was to investigate the localization and conjugal transfer of aminoglycoside resistance genes, aac(6')Ie-aph(2″)Ia and aph(3')IIIa in different Enterococcus species. The cross resistance patterns in Enterococcus faecalis MCC3063 to clinically important aminoglycosides by real time PCR were also studied. Southern hybridization experiments revealed the presence of aac(6')Ie-aph(2 ″ )Ia and aph(3')IIIa genes conferring HLAR in high molecular weight plasmids except in Lactobacillus plantarum. The plasmid encoded bifunctional aac(6')Ie-aph(2″)Ia gene was transferable from Enterococcus avium (n = 2), E. cecorum (n = 1), E. faecalis (n = 1) and Pediococcus lolii (n = 1) species into the recipient strain; E. faecalis JH2-2 by filter mating experiments thus indicating the possible risks of gene transfer into pathogenic strains. Molecular analysis of cross resistance patterns in native isolate of E. faecalis MCC3063 carrying aac(6')Ie-aph(2″)Ia and aph(3')IIIa gene was displayed by quantification of the mRNA levels in this study. For this, the culture was induced with increasing concentrations of gentamicin, kanamycin and streptomycin (2048, 4096, 8192, 16384 μg/mL) individually. The increasing concentrations of gentamicin and kanamycin induced the expression of the aac(6')Ie-aph(2″)Ia and aph(3')IIIa resistance genes, respectively. Interestingly, it was observed that induction with streptomycin triggered a significant fold increase in the expression of the aph(3')IIIa gene which otherwise was not known to modify the aminoglycoside. This is noteworthy as streptomycin was found to confer cross resistance to structurally unrelated kanamycin. Also, expression of the aph(3')IIIa gene when induced with streptomycin, revealed that bacteria harbouring this gene will be able to overcome streptomycin bactericidal action at

  18. Virulence and antibiotic resistance genes in Campylobacter spp. in the Czech Republic.

    Science.gov (United States)

    Bardoň, J; Pudová, V; Koláčková, I; Karpíšková, R; Röderová, M; Kolář, M

    2017-01-01

    Thermotolerant species of the genus Campy-lobacter are the important agents causing human foodborne infections throughout the world. The aims of this study were to evaluate the presence of nine putative virulence genes in Campylobacter spp. isolated from patients and from foods (poultry meat, pork liver), to determine the resistance of Campylobacter isolates to eight antibiotic agents and to detect four resistance genes.Matherial and methods: The presence of the virulence genes cdtA, cdtB, cdtC, virB11, ciaB, wlaN, iam, dnaJ and racR was detected by polymerase chain reaction (PCR) in 94 Campylobacter spp. isolates from humans and 123 campylobacters from foods. The phenotypic resistance to selected antimicrobial agents was tested with microdilution method in 82 human isolates and 91 food isolates. The isolates with antibiograms were tested for the presence of blaOXA-61, tet(O), aph-3-1 and cmeB genes by PCR with specific primers. In both human and food C. jejuni isolates the preva-lence of the studied virulence genes, especially dnaJ, racR, ciaB genes and the toxigenic genes cdtA, cdtB, cdtC, was considerably higher than in C. coli isolates. The only exception was the iam gene identified in only C. coli. The tested isolates of both C. jejuni and C. coli were highly resistant to quinolone antibiotics. Additionally, C. coli was also more resistant to erythromycin, streptomycin and, in case of isolates from pork liver, to tetracycline. High prevalence rates of genes encoding antibiotic resistance was noted for the blaOXA-61 and tet(O) genes in both Campylobacter species. The presented study is the first to assess the presence of genes for virulence and resistance to antibiotics in thermotolerant Campylobacter spp. isolated from humans and foods in the Czech Republic. The resistance of Campylobacter isolates to eight antibiotic agents was also assessed. The prevalence of genes responsible for virulence and resistance is rather varied in thermotolerant Campylobacter spp.

  19. Characterization of Aminoglycoside Resistance and Virulence Genes among Enterococcus spp. Isolated from a Hospital in China

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    Wanxiang Li

    2015-03-01

    Full Text Available This study investigated the aminoglycoside resistance phenotypes and genotypes, as well as the prevalence of virulence genes, in Enterococcus species isolated from clinical patients in China. A total of 160 enterococcal isolates from various clinical samples collected from September 2013 to July 2014 were identified to the species level using the VITEK-2 COMPACT system. The antimicrobial susceptibilities of the identified Enterococcus strains were determined by the Kirby-Bauer (K-B disc diffusion method. PCR-based assays were used to detect the aminoglycoside resistance and virulence genes in all enterococcal isolates. Of 160 Enterococcus isolates, 105 were identified as E. faecium, 35 as E. faecalis, and 20 isolates were classified as “other” Enterococcus species. High-level aminoglycoside resistance (HLAR for gentamicin, streptomycin, and both antibiotics was identified in 58.8, 50, and 34.4% of strains, respectively. The most common virulence gene (50.6% of isolates was efaA, followed by asa1 (28.8%. The most prevalent aminoglycoside resistance genes were aac(6'-Ie-aph(2'', aph(2'-Id, aph(3'-IIIa, and ant(6'-Ia, present in 49.4%, 1.3%, 48.8% and 31.3% of strains, respectively. Overall, E. faecium and E. faecalis were most frequently associated with hospital-acquired enterococcal infections in Zhejiang Province. All aminoglycoside resistance genes, except aph(2''-Id, were significantly more prevalent in HLAR strains than amongst high level aminoglycoside susceptible (HLAS strains, while there was no significant difference between HLAR and HLAS strains in regard to the prevalence of virulence genes, apart from esp, therefore, measures should be taken to manage infections caused by multi-drug resistant Enterococcus species.

  20. Characterization of Aminoglycoside Resistance and Virulence Genes among Enterococcus spp. Isolated from a Hospital in China

    Science.gov (United States)

    Li, Wanxiang; Li, Jing; Wei, Quhao; Hu, Qingfeng; Lin, Xiaowei; Chen, Mengquan; Ye, Renji; Lv, Huoyang

    2015-01-01

    This study investigated the aminoglycoside resistance phenotypes and genotypes, as well as the prevalence of virulence genes, in Enterococcus species isolated from clinical patients in China. A total of 160 enterococcal isolates from various clinical samples collected from September 2013 to July 2014 were identified to the species level using the VITEK-2 COMPACT system. The antimicrobial susceptibilities of the identified Enterococcus strains were determined by the Kirby-Bauer (K-B) disc diffusion method. PCR-based assays were used to detect the aminoglycoside resistance and virulence genes in all enterococcal isolates. Of 160 Enterococcus isolates, 105 were identified as E. faecium, 35 as E. faecalis, and 20 isolates were classified as “other” Enterococcus species. High-level aminoglycoside resistance (HLAR) for gentamicin, streptomycin, and both antibiotics was identified in 58.8, 50, and 34.4% of strains, respectively. The most common virulence gene (50.6% of isolates) was efaA, followed by asa1 (28.8%). The most prevalent aminoglycoside resistance genes were aac(6')-Ie-aph(2''), aph(2')-Id, aph(3')-IIIa, and ant(6')-Ia, present in 49.4%, 1.3%, 48.8% and 31.3% of strains, respectively. Overall, E. faecium and E. faecalis were most frequently associated with hospital-acquired enterococcal infections in Zhejiang Province. All aminoglycoside resistance genes, except aph(2'')-Id, were significantly more prevalent in HLAR strains than amongst high level aminoglycoside susceptible (HLAS) strains, while there was no significant difference between HLAR and HLAS strains in regard to the prevalence of virulence genes, apart from esp, therefore, measures should be taken to manage infections caused by multi-drug resistant Enterococcus species. PMID:25768240

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

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    A.C. Carvalho

    2016-03-01

    Full Text Available Abstract 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.

  2. Diversity of Plasmids and Antimicrobial Resistance Genes in Multidrug-Resistant Escherichia coli Isolated from Healthy Companion Animals.

    Science.gov (United States)

    Jackson, C R; Davis, J A; Frye, J G; Barrett, J B; Hiott, L M

    2015-09-01

    The presence and transfer of antimicrobial resistance genes from commensal bacteria in companion animals to more pathogenic bacteria may contribute to dissemination of antimicrobial resistance. The purpose of this study was to determine antimicrobial resistance gene content and the presence of genetic elements in antimicrobial resistant Escherichia coli from healthy companion animals. In our previous study, from May to August, 2007, healthy companion animals (155 dogs and 121 cats) from three veterinary clinics in the Athens, GA, USA area were sampled and multidrug-resistant E. coli (n = 36; MDR, resistance to ≥ 2 antimicrobial classes) were obtained. Of the 25 different plasmid replicon types tested by PCR, at least one plasmid replicon type was detected in 94% (34/36) of the MDR E. coli; four isolates contained as many as five different plasmid replicons. Nine replicon types (FIA, FIB, FII, I2, A/C, U, P, I1 and HI2) were identified with FIB, FII, I2 as the most common pattern. The presence of class I integrons (intI) was detected in 61% (22/36) of the isolates with eight isolates containing aminoglycoside- and/or trimethoprim-resistance genes in the variable cassette region of intI. Microarray analysis of a subset of the MDR E. coli (n = 9) identified the presence of genes conferring resistance to aminoglycosides (aac, aad, aph and strA/B), β-lactams (ampC, cmy, tem and vim), chloramphenicol (cat), sulfonamides (sulI and sulII), tetracycline [tet(A), tet(B), tet(C), tet(D) and regulator, tetR] and trimethoprim (dfrA). Antimicrobial resistance to eight antimicrobials (ampicillin, cefoxitin, ceftiofur, amoxicillin/clavulanic acid, streptomycin, gentamicin, sulfisoxazole and trimethoprim-sulfamethoxazole) and five plasmid replicons (FIA, FIB, FII, I1 and I2) were transferred via conjugation. The presence of antimicrobial resistance genes, intI and transferable plasmid replicons indicate that E. coli from companion animals may play an important role in the

  3. REVERSAL OF THE STREPTOMYCIN INJURY OF ESCHERICHIA COLI

    Science.gov (United States)

    Wasserman, Aaron E.; Lessner, James M.; West, Margaret K.

    1954-01-01

    The number of viable Escherichia coli in a young, actively growing culture is decreased approximately 99.9 per cent by a 30 second exposure to 25 φg. streptomycin/ml. The injury induced by the antibiotic is only potentially lethal, however, and may be reversed by subculture within 5 minutes into fresh culture medium, NH4NO3, NH4Cl, (NH4)2HPO4, NH4 citrate, and NH4 tartrate. Subculturing into water, glucose, or MgSO4 results in a more marked decrease in the number of viable organisms. In KNO3, NaNO3, K2HPO4, and Na2SO4 solutions reversal occurs first, followed by a rapid decrease in viability. True reversal of the streptomycin injury takes place, as demonstrated by the rapid rate of recovery to the viable count of the original culture. Development of resistance has been eliminated as the cause of regrowth since the streptomycin sensitivity of recovered cultures remained the same as that of the original culture. The use of water as diluent for viability determinations potentiates the lethal effect of streptomycin activity. Several compounds, at various dilutions, substituted for water as the diluent gave rise to four types of responses, group I, NH4NO3, NH4Cl, KNO3, NaNO3, Ca(NO3)2, showed complete reversal of the streptomycin injury at all levels of the salts tested, from 0.01 to 0.5 M concentrations. Group II, NaCl and K2HPO4 showed complete reversal at 0.03 and 0.1 M. Group III, glucose and urea allowed complete reversal at 0.5 M. Group IV, glycerol and glycerine showed no reversal at 0.5 M concentration. The reversal of the streptomycin injury to young actively growing bacteria is suggested as a tool for studying the pathology of the injury to the cells. PMID:13211997

  4. Antimicrobial resistance and class 1 integron-associated gene cassettes in Salmonella enterica serovar Typhimurium isolated from pigs at slaughter and abattoir environment.

    Science.gov (United States)

    Lopes, Graciela Volz; Michael, Geovana Brenner; Cardoso, Marisa; Schwarz, Stefan

    2016-10-15

    Forty-five multi-resistant Salmonella enterica subsp. enterica serovar (S.) Typhimurium isolates obtained at five pig abattoirs in Southern Brazil were characterized. Their relatedness was determined by XbaI-macrorestriction analysis. Resistance genes, integrons and plasmid-mediated quinolone resistance genes (PMQR) were investigated by PCR. Amplicons for the variable part of class 1 integrons and the quinolone resistance-determining regions (QRDR) were sequenced. Plasmids were characterized by conjugation assays and replicon typing. Eighteen XbaI-macrorestriction patterns and 19 plasmid profiles were seen. Resistance to ampicillin (bla TEM ), chloramphenicol (catA1 and floR), streptomycin (strA-strB), streptomycin/spectinomycin (aadA variants), sulphonamides (sul1, sul2, sul3) and tetracyclines [tet(A) and tet(B)] were commonly found. A trimethoprim resistance gene, dfrA8, was identified on a 100-kb plasmid. Single substitutions in the QRDR of GyrA but no PMQR genes were found. Twenty-five isolates carried class 1 integrons with an aadA23 gene cassette or unusual class 1 integrons with a dfrA12-orfF-aadA27 gene cassette array. Both integrons were found on large conjugative plasmids. Salmonella plasmid-located virulence genes spvR, spvA, spvB, rck and pefA were found on an IncFIB resistance plasmid. Hybrid virulence-resistance plasmids or plasmids harbouring class 1 integrons may play a role in the maintenance and dissemination of antimicrobial resistance among S. Typhimurium in this pig production system. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Plasmids carrying antimicrobial resistance genes in Enterobacteriaceae

    NARCIS (Netherlands)

    Rozwandowicz, M.; Brouwer, M.S.M.; Fischer, J.; Wagenaar, J.A.; Gonzalez-Zorn, B.; Guerra, B.; Mevius, D.J.; Hordijk, J.

    2018-01-01

    Bacterial antimicrobial resistance (AMR) is constantly evolving and horizontal gene transfer through plasmids plays a major role. The identification of plasmid characteristics and their association with different bacterial hosts provides crucial knowledge that is essential to understand the

  6. Identification of acquired antimicrobial resistance genes

    DEFF Research Database (Denmark)

    Zankari, Ea; Hasman, Henrik; Cosentino, Salvatore

    2012-01-01

    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 laborato......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...... antimicrobial resistance genes in whole-genome data. As input, the method can use both pre-assembled, complete or partial genomes, and short sequence reads from four different sequencing platforms. The method was evaluated on 1862 GenBank files containing 1411 different resistance genes, as well as on 23 de...

  7. [ISOLATION OF ANTIBIOTICS RESISTANCE GENES IN VIBRIO CHOLERAE O1 AND O139 SEROGROUP STRAINS].

    Science.gov (United States)

    Zadnova, S P; Smirnova, N I

    2015-01-01

    Determination of sensitivity of V. cholerae O1 serogroup El Tor biovar and O139 serogroup strains to antibiotics and determination of the presence of antibiotics resistance genes in their genome. The studies were carried out in 75 V. cholerae O1 and O139 serogroup strains. Sensitivity of cultures to antibiotics was determined by disc-diffusion method. DNA isolation was carried out in the presence of 6M guanidine thiocyanate. PCR was carried out in multi-channel amplificator Tercyc. A multiplex PCR was constructed, that includes 5 primer pairs for the detection of O1 and O139 serogroup resistance genes of vibrios to sulfame- thoxazolum, streptomycin B, trimethoprim, the presence of SXT element, an amplification program was developed. Using the developed PCR, V. cholerae O1 serogroup El Tor biovar strains with multiple drug resistance were established to be imported into Russia in 1993. The presence of SXT elements with genes of resistance to 4 antibiotics simultaneously was detected precisely in these strains, that belong to toxigenic genovariants of V. cholerae El Tor biovar. All the El Tor vibrio strains imported in the subsequent years were shown to stably preserve SXT element, this indicates its important role in biology of cholera vibrios. O139 serogroup strains with intact SXT element and having a deletion of the gene coding trimethoprim resistance were isolated. The data obtained may be used to establish molecular-genetic mechanisms of emergence of antibiotics resistant strains of cholera vibrio, construction of novel gene diagnostic test-systems and carrying out passportization of strains that are stored in the State collection of pathogenic bacteria.

  8. Antimicrobial resistance and virulence genes in Escherichia coli and enterococci from red foxes (Vulpes vulpes).

    Science.gov (United States)

    Radhouani, Hajer; Igrejas, Gilberto; Gonçalves, Alexandre; Pacheco, Rui; Monteiro, Ricardo; Sargo, Roberto; Brito, Francisco; Torres, Carmen; Poeta, Patrícia

    2013-10-01

    The aims of the study were to analyse the prevalence of antimicrobial resistance and the mechanisms implicated, as well as the virulence factors, in faecal Escherichia coli and Enterococcus spp. from red foxes. From 52 faecal samples, 22 E. coli (42.3%) and 50 enterococci (96.2%) isolates were recovered (one/sample). A high percentage of E. coli isolates exhibited resistance to streptomycin, tetracycline, trimethoprim-sulfamethoxazole or ampicillin (54-27%), and they harboured the aadA, tet(A) and/or tet(B), sul1 and blaTEM resistance genes, respectively. The E. coli isolates were ascribed to the 4 major phylogroups, D (41% of isolates), A (31.8%), B1 (18.2%) and B2 (9.1%), and carried the fimA (63.3%) or aer (13.6%) virulence genes. Among enterococcal isolates, Enterococcus faecium was the most prevalent species (50%). A high percentage of enterococcal isolates showed tetracycline resistance (88%) harbouring different combinations of tet(M) and tet(L) genes. The erm(B) or the aph(3')-IIIa gene were identified in most of our erythromycin- or kanamycin-resistant enterococci, respectively. This report suggests the role of red foxes from rural areas in the cycle of transmission and spread of antimicrobial-resistant E. coli and enterococci into the environment, representing a reservoir of these antimicrobial-resistant microorganisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Regional dissemination of a trimethoprim-resistance gene cassette via a successful transposable element.

    Directory of Open Access Journals (Sweden)

    Amy S Labar

    Full Text Available Antimicrobial resistance is a growing international problem. We observed a 50% increase in the prevalence of trimethoprim resistance among fecal Escherichia coli from healthy Nigerian students between 1998 and 2005, a trend to increase that continued in 2009.A PCR-based screen revealed that 131 (43.1% of isolates obtained in Nigeria in 2005 and 2009 carried integron-borne dfrA cassettes. In the case of 67 (51.1% of these isolates, the cassette was a class 1-integron-borne dfrA7 gene, which has been reported at high prevalence from E. coli isolates from other parts of Africa. Complete sequencing of a 27 Kb dfrA7-bearing plasmid from one isolate located the dfrA7 gene within a Tn21-type transposon. The transposon also contained an IS26-derived bla/sul/str element, encoding resistance to β-lactams, sulphonamides and streptomycin, and mercury resistance genes. Although the plasmid backbone was only found in 12 (5.8% of trimethoprim-resistant isolates, dfrA7 and other transposon-borne genes were detected in 14 (16.3% and 32 (26.3% of trimethoprim resistant isolates collected in Nigeria in 2005 and 2009, respectively. Additionally, 37 (19.3% of trimethoprim-resistant E. coli isolates collected between 2006 and 2008 from Ghana were positive for the dfrA7 and a transposon marker, but only 4 (2.1% harbored the plasmid backbone.Our data point to transposition as a principal mechanism for disseminating dfrA7 among E. coli from Nigeria and Ghana. On-going intensive use of the affordable broad-spectrum antibacterials is likely to promote selective success of a highly prevalent transposable element in West Africa.

  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. 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.

  12. 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 .

  13. Establishing streptomycin epidemiological cut-off values for Salmonella and Escherichia coli.

    Science.gov (United States)

    Garcia-Migura, Lourdes; Sunde, Marianne; Karlsmose, Susanne; Veldman, Kees; Schroeter, Andreas; Guerra, Beatriz; Granier, Sophie A; Perrin-Guyomard, Agnès; Gicquel-Bruneau, Mireille; Franco, Alessia; Englund, Stina; Teale, Christopher; Heiska, Helmi; Clemente, Lurdes; Boerlin, Patrick; Moreno, Miguel A; Daignault, Danielle; Mevius, Dik; Hendriksen, Rene S; Aarestrup, Frank M

    2012-02-01

    This study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ECOFF) for Escherichia coli and Salmonella spp. A total of 236 Salmonella enterica and 208 E. coli isolates exhibiting MICs between 4 and 32 mg/L were selected from 12 countries. Isolates were investigated by polymerase chain reaction for aadA, strA, and strB streptomycin resistance genes. Out of 236 Salmonella isolates, 32 (13.5%) yielded amplicons for aadA (n = 23), strA (n = 9), and strB (n = 11). None of the 60 Salmonella isolates exhibiting MIC 4 mg/L harbored resistance genes. Of the Salmonella isolates exhibiting MICs 8 mg/L, 16 mg/L, and 32 mg/L, 1.6%, 15%, and 39%, respectively, tested positive for one or more genes. For most monitoring programs, the streptomycin ECOFF for Salmonella is wild type (WT) ≤32 or ≤16 mg/L. A cut-off value of WT ≤32 mg/L would have misclassified 13.5% of the strains as belonging to the WT population, since this proportion of strains harbored resistance genes and exhibited MICs ≤32 mg/L. Out of 208 E. coli strains, 80 (38.5%) tested positive for aadA (n = 69), strA (n = 18), and strB (n = 31). Of the E. coli isolates exhibiting MICs of 4 mg/L, 8 mg/L, 16 mg/L, and 32 mg/L, 3.6%, 17.6%, 53%, and 82.3%, respectively, harbored any of the three genes. Based on the European Committee on Antimicrobial Susceptibility Testing guidelines (ECOFF ≤16 mg/L), 25% of the E. coli strains presenting MIC ≤16 mg/L would have been incorrectly categorized as belonging to the WT population. The authors recommend an ECOFF value of WT ≤16 mg/L for Salmonella and WT ≤8 mg/L for E. coli.

  14. The potent bactericidal activity of streptomycin in the guinea pig model of tuberculosis ceases due to the presence of persisters.

    Science.gov (United States)

    Ahmad, Zahoor; Pinn, Michael L; Nuermberger, Eric L; Peloquin, Charles A; Grosset, Jacques H; Karakousis, Petros C

    2010-10-01

    The biphasic kill curve of isoniazid against Mycobacterium tuberculosis in guinea pigs is due to the presence of persisters rather than selection of isoniazid-resistant mutants. To determine whether this phenomenon is common to other bactericidal drugs, we studied the activity of streptomycin and its ability to select for streptomycin-resistant mutants in the guinea pig model of tuberculosis. Pharmacokinetic studies were performed to establish the human-equivalent dose of streptomycin. Guinea pigs were aerosol-infected with M. tuberculosis and 2 weeks later streptomycin was given for 5 days/week via intramuscular injection. Bactericidal activity was assessed by homogenizing and plating lungs for cfu until 10 weeks of treatment. At each timepoint, cfu were isolated, suspended in normal saline and re-plated on plates containing 0.5, 1.0, 2.0 or 10.0 mg/L streptomycin. The human-equivalent dose of streptomycin was determined to be 70 mg/kg. Streptomycin showed potent activity during the first 14 days of treatment, rescuing all animals from acute tuberculosis-related death and reducing lung cfu by ∼4 log(10). However, streptomycin activity was dramatically reduced thereafter, as lung cfu declined by only ∼1 log(10) over the next 56 days of treatment. Although streptomycin-resistant mutants were detectable, their frequency of isolation was identical at treatment initiation and after 70 days of treatment. The reduced activity of streptomycin during the second phase of monotherapy is not associated with the selection of streptomycin-resistant mutants but, rather, with the presence of phenotypically tolerant 'persisters'.

  15. Assessment of strains of Pseudomonas syringae pv. tomato from Tanzania for resistance to copper and streptomycin

    DEFF Research Database (Denmark)

    Shenge, K.C.; Wydra, K.; Mabagala, M.B.

    2008-01-01

    Fifty-six strains of Pseudomonas syringae pv. tomato (P.s. pv. tomato) were collected from tomato-producing areas in Tanzania and assessed for resistance to copper and antibiotics. The collection was done from three tomato-producing regions (Morogoro, Arusha and Iringa), representing three differ...

  16. [Investigation of molecular mechanisms of aminoglycoside resistance in Salmonella].

    Science.gov (United States)

    Zubritskiĭ, A V; Il'ina, E N; Strel'chenko, S A; Malakhova, M V; Lenev, S V; Skliarov, O D; Panin, A N; Govorun, V M

    2011-01-01

    The spread of aminoglycoside resistance phenotype and respective genetic resistance determinants was evaluated in 243 Salmonella strains isolated within 1948-2010 and stored in the Culture Collection of the Russian State Research Institute for Control, Standardization and Certification of Veterinary Preparations (Moscow). The Salmonella strains showed resistance to streptomycin and gentamicin in 3.7% (n = 9) and 0.8% (n = 2) of the isolates respectively. Intermediate resistance to streptomycin was recorded in 9.9% (n = 24) of the isolates. To detect the genes responsible for the aminoglycoside resistance, primers for aadA1, aadA2, aadB, aphA1, aphA3, sat, strA, strB, aphA, aacC, rmtB, armA and rpsL genes amplification and sequencing were designed. The strains with lower susceptibility to streptomycin harbored aadA1, aadA2, strA, strB resistance genes encoding enzymes for aminoglicoside modification and rpsL mutant allele (K42N, G91D). Genetic mechanisms able to explain the gentamicin resistance development were not detected. Some strains carried genetic markers of streptomycine resistance but had no clinically sufficient resistance to it. In this regard, genetic testing is essential for prevention of drug resistance spreading due to horizontal transfer of genes in microbial population.

  17. Bactericidal Action of Streptomycin and Comparison with Spectinomycin in Heterozygotes of Escherichia coli

    Science.gov (United States)

    Sparling, P. Frederick; Davis, Bernard D.

    1972-01-01

    Strs/strr heterozygotes of Escherichia coli K-12 are shown to be sensitive to the lethal as well as the inhibitory action of streptomycin. The rate of killing was lower in heterozygotes than in sensitive homozygotes, and among heterozygotes it was lower in those with a higher proportion of resistant ribosomes. These strains also differed, in a parallel manner, in the kinetics of inhibition of growth and protein synthesis by streptomycin. Similar results were obtained with spectinomycin and corresponding merodiploid strains. Since spectinomycin is purely bacteriostatic and stabilizes polysomes, it must block resistant ribosomes behind inhibited sensitive ribosomes; hence, these results are consistent with an initial similar polysomal blockade by streptomycin. However, since streptomycin causes gradual polysome breakdown, its dominant lethal action must involve some mechanism other than a permanent polysomal blockade. PMID:4261554

  18. 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...

  19. Purification and Characterization of Aminoglycoside Phosphotransferase APH(6)-Id, a Streptomycin Inactivating Enzyme

    OpenAIRE

    Ashenafi, Meseret; Ammosova, Tatiana; Nekhai, Sergei; Byrnes, W. Malcolm

    2013-01-01

    As part of an overall project to characterize the streptomycin phosphotransferase enzyme APH(6)-Id, which confers bacterial resistance to streptomycin, we cloned, expressed, purified and characterized the enzyme. When expressed in E. coli, the recombinant enzyme increased by up to 70-fold the minimum inhibitory concentration (MIC) needed to inhibit cell growth. Size exclusion chromatography gave a molecular mass of 31.4 ± 1.3 kDa for the enzyme, showing that it functions as a monomer. Activit...

  20. Impairing methylations at ribosome RNA, a point mutation-dependent strategy for aminoglycoside resistance: the rsmG case.

    Science.gov (United States)

    Benítez-Páez, Alfonso; Cárdenas-Brito, Sonia; Corredor, Mauricio; Villarroya, Magda; Armengod, María Eugenia

    2014-04-01

    Aminoglycosides like streptomycin are well-known for binding at specific regions of ribosome RNA and then acting as translation inhibitors. Nowadays, several pathogens have been detected to acquire an undefined strategy involving mutation at non structural ribosome genes like those acting as RNA methylases. rsmG is one of those genes which encodes an AdoMet-dependent methyltransferase responsible for the synthesis of m 7 G527 in the 530 loop of bacterial 16S rRNA. This loop is universally conserved, plays a key role in ribosomal accuracy, and is a target for streptomycin binding. Loss of the m 7 G527 modification confers low-level streptomycin resistance and may affect ribosomal functioning. After taking into account genetic information indicating that some clinical isolates of human pathogens show streptomycin resistance associated with mutations at rsmG , we decided to explore new hot spots for mutation capable of impairing the RsmG in vivo function and of promoting low-level streptomycin resistance. To gain insights into the molecular and genetic mechanism of acquiring this aminoglycoside resistance phenotype and the emergence of high-level streptomycin resistance in rsmG mutants, we mutated Escherichia coli rsmG and also performed a genotyping study on rpsL from several isolates showing the ability to grow at higher streptomycin concentrations than parental strains. We found that the mutations at rpsL were preferentially present in these mutants, and we observed a clear synergy between rsmG and rpsL genes to induce streptomycin resistance. We contribute to understand a common mechanism that is probably transferable to other ribosome RNA methylase genes responsible for modifications at central sites for ribosome function.

  1. Expression Study of Banana Pathogenic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Fenny M. Dwivany

    2016-10-01

    Full Text Available Banana is one of the world's most important trade commodities. However, infection of banana pathogenic fungi (Fusarium oxysporum race 4 is one of the major causes of decreasing production in Indonesia. Genetic engineering has become an alternative way to control this problem by isolating genes that involved in plant defense mechanism against pathogens. Two of the important genes are API5 and ChiI1, each gene encodes apoptosis inhibitory protein and chitinase enzymes. The purpose of this study was to study the expression of API5 and ChiI1 genes as candidate pathogenic resistance genes. The amplified fragments were then cloned, sequenced, and confirmed with in silico studies. Based on sequence analysis, it is showed that partial API5 gene has putative transactivation domain and ChiI1 has 9 chitinase family GH19 protein motifs. Data obtained from this study will contribute in banana genetic improvement.

  2. Antimicrobial susceptibilities and resistance genes in Campylobacter strains isolated from poultry and pigs in Australia.

    Science.gov (United States)

    Obeng, A S; Rickard, H; Sexton, M; Pang, Y; Peng, H; Barton, M

    2012-08-01

    To evaluate the phenotypic and genotypic profiles of Campylobacter spp. from poultry faecal samples from free range or intensively raised meat chickens and free range egg layers. In addition, a case-comparison study of antibiotic resistance genes from different groups of poultry and some pig strains previously collected was carried out. Resistance to different antibiotics was assessed using the agar dilution method. In addition, all the strains were tested for ampicillin (bla(OXA-61) ), erythromycin (aph-3-1), tetracycline tet(O), streptomycin (aadE), and the energy-dependent multi-drug efflux pump (cmeB) resistance genes using multiplex polymerase chain reaction. The evaluation of phenotypic resistance revealed all of the strains from poultry were sensitive to ciprofloxacin, gentamicin, erythromycin or tylosin. But, widespread resistance to lincomycin (51-100%), extensive resistance to ampicillin (33·3-60·2%) and less resistance to tetracycline (5·6-40·7%) were observed in the different groups of chickens. Antibiotic resistance genes bla(OXA-61,) cmeB and tet(O) were found in 82·6-92·7%, 80·3-89% and 22·3-30·9% Camp. coli isolates from pigs, whilst 59-65·4% and 19·2-40·7% Camp. jejuni from chickens were found to encode bla(OXA-61) and tet(O), respectively. No significant difference between isolates from free range egg layers and meat chickens (P resistance genes. In addition, pulsed field gel electrophoresis of selected resistant isolates from the poultry and pig revealed closely related clonal groups. Our results suggest the resistant strains are persisting environmental isolates that have been acquired by the different livestock species. Furthermore, the different treatment practices in poultry and pigs have resulted in differences in resistance profiles in Campylobacter isolates. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

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

    Indian Academy of Sciences (India)

    ... rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%.

  4. Antibiotic-Resistance Genes in Waste Water.

    Science.gov (United States)

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

    2018-03-01

    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.

  5. Seawater is a reservoir of multi-resistant Escherichia coli, including strains hosting plasmid-mediated quinolones resistance and extended-spectrum beta-lactamases genes

    Directory of Open Access Journals (Sweden)

    Marta S. Alves

    2014-08-01

    Full Text Available The aim of this study was to examine antibiotic resistance (AR dissemination in coastal water, considering the contribution of different sources of faecal contamination. Samples were collected in Berlenga, an uninhabited island classified as Natural Reserve and visited by tourists for aquatic recreational activities. To achieve our aim, AR in Escherichia coli isolates from coastal water was compared to AR in isolates from two sources of faecal contamination: human-derived sewage and seagull faeces. Isolation of E. coli was done on Chromocult agar. Based on genetic typing 414 strains were established. Distribution of E. coli phylogenetic groups was similar among isolates of all sources. Resistances to streptomycin, tetracycline, cephalothin and amoxicillin were the most frequent. Higher rates of AR were found among seawater and faeces isolates, except for last-line antibiotics used in human medicine. Multi-resistance rates in isolates from sewage and seagull faeces (29% and 32% were lower than in isolates from seawater (39%. Seawater AR profiles were similar to those from seagull faeces and differed significantly from sewage AR profiles. Nucleotide sequences matching resistance genes blaTEM, sul1, sul2, tet(A and tet(B, were present in isolates of all sources. Genes conferring resistance to 3rd generation cephalosporins were detected in seawater (blaCTX-M-1 and blaSHV-12 and seagull faeces (blaCMY-2. Plasmid-mediated determinants of resistance to quinolones were found: qnrS1 in all sources and qnrB19 in seawater and seagull faeces. Our results show that seawater is a relevant reservoir of AR and that seagulls are an efficient vehicle to spread human-associated bacteria and resistance genes. The E. coli resistome recaptured from Berlenga coastal water was mainly modulated by seagulls-derived faecal pollution. The repertoire of resistance genes covers antibiotics critically important for humans, a potential risk for human health.

  6. Quadruple-first line drug resistance in Mycobacterium tuberculosis in Vietnam: What can we learn from genes?

    Science.gov (United States)

    Nguyen, Huy Quang; Nguyen, Nhung Viet; Contamin, Lucie; Tran, Thanh Hoa Thi; Vu, Thuong Thi; Nguyen, Hung Van; Nguyen, Ngoc Lan Thi; Nguyen, Son Thai; Dang, Anh Duc; Bañuls, Anne-Laure; Nguyen, Van Anh Thi

    2017-06-01

    In Vietnam, a country with high tuberculosis (137/100.000 population) and multidrug-resistant (MDR)-TB burdens (7.8/100.000 population), little is known about the molecular signatures of drug resistance in general and more particularly of second line drug (SLD) resistance. This study is specifically focused on Mycobacterium tuberculosis isolates resistant to four first-line drugs (FLDs) that make TB much more difficult to treat. The aim is to determine the proportion of SLD resistance in these quadruple drug resistant isolates and the genetic determinants linked to drug resistance to better understand the genetic processes leading to quadruple and extremely drug resistance (XDR). 91 quadruple (rifampicin, isoniazid, ethambutol and streptomycin) FLD resistant and 55 susceptible isolates were included. Spoligotyping and 24-locus MIRU-VNTR techniques were performed and 9 genes and promoters linked to FLD and SLD resistance were sequenced. SLD susceptibility testing was carried out on a subsample of isolates. High proportion of quadruple-FLD resistant isolates was resistant to fluoroquinolones (27%) and second-line injectable drugs (30.2%) by drug susceptibility testing. The sequencing revealed high mutation diversity with prevailing mutations at positions katG315, inhA-15, rpoB531, embB306, rrs1401, rpsL43 and gyrA94. The sensitivity and specificity were high for most drug resistances (>86%), but the sensitivity was lower for injectable drug resistances (resistance. Nevertheless, particular mutation patterns linked to high-level resistance and low fitness costs seem to be favored. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. RAPD PCR Profile, Antibiotic Resistance, Prevalence of armA Gene, and Detection of KPC Enzyme in Klebsiella pneumoniae Isolates

    Directory of Open Access Journals (Sweden)

    Arezoo Saadatian Farivar

    2018-01-01

    Full Text Available The increasing prevalence of multidrug-resistant Klebsiella pneumoniae strains isolated from hospitals shows the limitation of recent antibiotics used for bacterial eradication. In this study, 81 K. pneumoniae isolates were collected from three hospitals in Tehran. Antibiotic susceptibility test showed the highest rates of resistance to cefotaxim (85.5% and ceftazidime (78.3%, and the lowest rates of resistance were detected for colistin (16.9%, streptomycin (16.8%, and chloroamphenicol (21.7%. Eleven different resistance patterns were observed. Sixty-six out of 81 isolates (81.5% were found to be multidrug resistant (MDR, and 35.8% of them belonged to A3 resistance pattern. 7.4% and 66.7% were KPC enzyme and armA gene positive, respectively. RAPD PCR assay of these bacteria showed 5 clusters, 16 single types, and 14 common types, and there was not any correlation between genetic patterns of the isolates and presence of resistance agents. Simultaneous detection of resistance-creating agents could be an important challenge for combination therapy of MDR K. pneumoniae-caused infections.

  8. 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.

  9. Mutant ribosomes can generate dominant kirromycin resistance.

    Science.gov (United States)

    Tubulekas, I; Buckingham, R H; Hughes, D

    1991-01-01

    Mutations in the two genes for EF-Tu in Salmonella typhimurium and Escherichia coli, tufA and tufB, can confer resistance to the antibiotic kirromycin. Kirromycin resistance is a recessive phenotype expressed when both tuf genes are mutant. We describe a new kirromycin-resistant phenotype dominant to the effect of wild-type EF-Tu. Strains carrying a single kirromycin-resistant tuf mutation and an error-restrictive, streptomycin-resistant rpsL mutation are resistant to high levels of kirromycin, even when the other tuf gene is wild type. This phenotype is dependent on error-restrictive mutations and is not expressed with nonrestrictive streptomycin-resistant mutations. Kirromycin resistance is also expressed at a low level in the absence of any mutant EF-Tu. These novel phenotypes exist as a result of differences in the interactions of mutant and wild-type EF-Tu with the mutant ribosomes. The restrictive ribosomes have a relatively poor interaction with wild-type EF-Tu and are thus more easily saturated with mutant kirromycin-resistant EF-Tu. In addition, the mutant ribosomes are inherently kirromycin resistant and support a significantly faster EF-Tu cycle time in the presence of the antibiotic than do wild-type ribosomes. A second phenotype associated with combinations of rpsL and error-prone tuf mutations is a reduction in the level of resistance to streptomycin. PMID:2050625

  10. 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.

  11. Increasing Prevalence of Aminoglycoside-Resistant Enterococcus faecalis Isolates Due to the aac(6')-aph(2") Gene: A Therapeutic Problem in Kermanshah, Iran.

    Science.gov (United States)

    Khani, Mitra; Fatollahzade, Mahdie; Pajavand, Hamid; Bakhtiari, Somaye; Abiri, Ramin

    2016-03-01

    Enterococci are important pathogens in nosocomial infections. Various types of antibiotics, such as aminoglycosides, are used for treatment of these infections. Enterococci can acquire resistant traits, which can lead to therapeutic problems with aminoglycosides. This study was designed to identify the prevalence of, and to compare, the aac(6')-aph(2") and aph(3)-IIIa genes and their antimicrobial resistance patterns among Enterococcus faecalis and E. faecium isolates from patients at Imam Reza hospital in Kermanshah in 2011 - 2012. One hundred thirty-eight clinical specimens collected from different wards of Imam Reza hospital were identified to the species level by biochemical tests. Antimicrobial susceptibility tests against kanamycin, teicoplanin, streptomycin, imipenem, ciprofloxacin, and ampicillin were performed by the disk diffusion method. The minimum inhibitory concentrations of gentamicin, streptomycin, kanamycin, and amikacin were evaluated with the microbroth dilution method. The aminoglycoside resistance genes aac(6')-aph(2") and aph(3")-IIIa were analyzed with multiplex PCR. The prevalence of isolates was 33 (24.1%) for E. faecium and 63 (46%) for E. faecalis. Eighty-nine percent of the isolates were high-level gentamicin resistant (HLGR), and 32.8% of E. faecium isolates and 67.2% of E. faecalis isolates carried aac(6')-aph(2"). The prevalence of aph(3")-IIIa among the E. faecalis and E. faecium isolates was 22.7% and 77.3%, respectively. Remarkably increased incidence of aac(6')-aph(2") among HLGR isolates explains the relationship between this gene and the high level of resistance to aminoglycosides. As the resistant gene among enterococci can be transferred, the use of new-generation antibiotics is necessary.

  12. Plant resistance genes : their structure, function and evolution

    NARCIS (Netherlands)

    Takken, F.L.W.; Joosten, M.H.A.J.

    2000-01-01

    Plants have developed efficient mechanisms to avoid infection or to mount responses that render them resistant upon attack by a pathogen. One of the best-studied defence mechanisms is based on gene-for-gene resistance through which plants, harbouring specific resistance (R) genes, specifically

  13. Effect of Streptomycin Deprivation on Enzyme Synthesis in Streptomycin-Dependent Escherichia coli

    Science.gov (United States)

    Goodman, R. E.; Spotts, Charles R.

    1967-01-01

    During growth of streptomycin-dependent strains of Escherichia coli in the absence of streptomycin (deprived growth), both constitutive and inducible synthesis of β-galactosidase were preferentially inhibited. A similar preferential inhibition of constitutive and derepressed synthesis of alkaline phosphatase was observed. Catabolite repression accounted for part, but not all, of the inhibition of the inducible β-galactosidase synthesis. Serological experiments indicated that that part of the inhibition specificially associated with streptomycin deprivation was not a result of the production of altered β-galactosidase. It is suggested that during deprived growth the ribosomes of streptomycin-dependent bacteria become impaired in their ability to translate certain messages. PMID:4860910

  14. Streptomycin causes misreading of natural messenger by interacting with ribosomes after initiation.

    Science.gov (United States)

    Tai, P C; Wallace, B J; Davis, B D

    1978-01-01

    The induction of misreading by streptomycin in vitro, previously observed with synthetic messengers, is now demonstrated with natural (endogenous or viral) messenger by the use of extracts of temperature sensitive mutants lacking Glu--tRNA or Val--tRNA synthetase. With chain-elongating but noninitiating ribosomes (i.e., purified polysomes) deprived of an aminoacyl--tRNA, streptomycin and other aminoglycosides, over a wide range of concentrations, stimulate incorporation. With ribosomes initiating in the presence of streptomycin stimulation is also observed but it is restricted, just like phenotypic suppression in cells, to very low streptomycin concentrattions which evidently allow some ribosomes to initiate and later encounter them in the course of chain elongation. The stimulation is accompanied by an increase in the size of the products; hence, it is evidently due to substitution of an incorrect aminoacyl--tRNA for a missing one. The test introduced here also has revealed a misreading effect of streptomycin on resistant ribosomes. In addition, significant intrinsic misreading was observed without streptomycin, indicating that under optimal conditions for in vitro protein synthesis an empty codon is frequently read by an incorrect aminoacyl--tRNA.

  15. Coevolution of antibiotic production and counter-resistance in soil bacteria.

    Science.gov (United States)

    Laskaris, Paris; Tolba, Sahar; Calvo-Bado, Leo; Wellington, Elizabeth M; Wellington, Liz

    2010-03-01

    We present evidence for the coexistence and coevolution of antibiotic resistance and biosynthesis genes in soil bacteria. The distribution of the streptomycin (strA) and viomycin (vph) resistance genes was examined in Streptomyces isolates. strA and vph were found either within a biosynthetic gene cluster or independently. Streptomyces griseus strains possessing the streptomycin cluster formed part of a clonal complex. All S. griseus strains possessing solely strA belonged to two clades; both were closely related to the streptomycin producers. Other more distantly related S. griseus strains did not contain strA. S. griseus strains with only vph also formed two clades, but they were more distantly related to the producers and to one another. The expression of the strA gene was constitutive in a resistance-only strain whereas streptomycin producers showed peak strA expression in late log phase that correlates with the switch on of streptomycin biosynthesis. While there is evidence that antibiotics have diverse roles in nature, our data clearly support the coevolution of resistance in the presence of antibiotic biosynthetic capability within closely related soil dwelling bacteria. This reinforces the view that, for some antibiotics at least, the primary role is one of antibiosis during competition in soil for resources.

  16. Reversing Bacterial Resistance to Antibiotics by Phage-Mediated Delivery of Dominant Sensitive Genes

    Science.gov (United States)

    Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar

    2012-01-01

    Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA conferring sensitivity in a dominant fashion to two antibiotics, streptomycin and nalidixic acid, respectively. Unique selective pressure is generated to enrich for bacteria that harbor the phages carrying the sensitizing constructs. This selection pressure is based on a toxic compound, tellurite, and therefore does not forfeit any antibiotic for the sensitization procedure. We further demonstrate a possible way of reducing undesirable recombination events by synthesizing dominant sensitive genes with major barriers to homologous recombination. Such synthesis does not significantly reduce the gene's sensitization ability. Unlike conventional bacteriophage therapy, the system does not rely on the phage's ability to kill pathogens in the infected host, but instead, on its ability to deliver genetic constructs into the bacteria and thus render them sensitive to antibiotics prior to host infection. We believe that transfer of the sensitizing cassette by the constructed phage will significantly enrich for antibiotic-treatable pathogens on hospital surfaces. Broad usage of the proposed system, in contrast to antibiotics and phage therapy, will potentially change the nature of nosocomial infections toward being more susceptible to antibiotics rather than more resistant. PMID:22113912

  17. Mutant ribosomes can generate dominant kirromycin resistance.

    OpenAIRE

    Tubulekas, I; Buckingham, R H; Hughes, D

    1991-01-01

    Mutations in the two genes for EF-Tu in Salmonella typhimurium and Escherichia coli, tufA and tufB, can confer resistance to the antibiotic kirromycin. Kirromycin resistance is a recessive phenotype expressed when both tuf genes are mutant. We describe a new kirromycin-resistant phenotype dominant to the effect of wild-type EF-Tu. Strains carrying a single kirromycin-resistant tuf mutation and an error-restrictive, streptomycin-resistant rpsL mutation are resistant to high levels of kirromyci...

  18. Partial Sequencing of 16S rRNA Gene of Selected Staphylococcus aureus Isolates and its Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Harsi Dewantari Kusumaningrum

    2016-08-01

    Full Text Available The choice of primer used in 16S rRNA sequencing for identification of Staphylococcus species found in food is important. This study aimed to characterize Staphylococcus aureus isolates by partial sequencing based on 16S rRNA gene employing primers 16sF, 63F or 1387R. The isolates were isolated from milk, egg dishes and chicken dishes and selected based on the presence of sea gene that responsible for formation of enterotoxin-A. Antibiotic susceptibility of the isolates towards six antibiotics was also tested. The use of 16sF resulted generally in higher identity percentage and query coverage compared to the sequencing by 63F or 1387R. BLAST results of all isolates, sequenced by 16sF, showed 99% homology to complete genome of four S. aureus strains, with different characteristics on enterotoxin production and antibiotic resistance. Considering that all isolates were carrying sea gene, indicated by the occurence of 120 bp amplicon after PCR amplification using primer SEA1/SEA2,  the isolates were most in agreeing to S. aureus subsp. aureus ST288. This study indicated that 4 out of 8 selected isolates were resistant towards streptomycin. The 16S rRNA gene sequencing using 16sF is useful for identification of S. aureus. However, additional analysis such as PCR employing specific gene target, should give a valuable supplementary information, when specific characteristic is expected.

  19. 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...

  20. Marker mapping and resistance gene associations in soybean

    OpenAIRE

    2011-01-01

    The invention provides novel molecular genetic markers in soybean, where the markers are useful, for example, in the marker-assisted selection of gene alleles that impart disease-resistance, thereby allowing the identification and selection of a disease-resistant plant. The markers also find use in positional cloning of disease-resistance genes.

  1. Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

    OpenAIRE

    Cloeckaert, Axel; Schwarz, Stefan

    2001-01-01

    International audience; Multidrug-resistant Salmonella enterica serovar Typhimurium phage type DT104 has emerged during the last decade as a global health problem because of its involvement in diseases in animals and humans. Multidrug-resistant DT104 strains are mostly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracyclines (ACSSuT resistance type). The genes coding for such resistances are clustered on the chromosome. This paper reviews new developments in the ...

  2. Efflux pump genes of the resistance-nodulation-division family in Burkholderia cenocepacia genome

    Directory of Open Access Journals (Sweden)

    Manina Giulia

    2006-07-01

    Full Text Available Abstract Background Burkholderia cenocepacia is recognized as opportunistic pathogen that can cause lung infections in cystic fibrosis patients. A hallmark of B. cenocepacia infections is the inability to eradicate the organism because of multiple intrinsic antibiotic resistance. As Resistance-Nodulation-Division (RND efflux systems are responsible for much of the intrinsic multidrug resistance in Gram-negative bacteria, this study aims to identify RND genes in the B. cenocepacia genome and start to investigate their involvement into antimicrobial resistance. Results Genome analysis and homology searches revealed 14 open reading frames encoding putative drug efflux pumps belonging to RND family in B. cenocepacia J2315 strain. By reverse transcription (RT-PCR analysis, it was found that orf3, orf9, orf11, and orf13 were expressed at detectable levels, while orf10 appeared to be weakly expressed in B. cenocepacia. Futhermore, orf3 was strongly induced by chloramphenicol. The orf2 conferred resistance to fluoroquinolones, tetraphenylphosphonium, streptomycin, and ethidium bromide when cloned and expressed in Escherichia coli KAM3, a strain lacking the multidrug efflux pump AcrAB. The orf2-overexpressing E. coli also accumulate low concentrations of ethidium bromide, which was restored to wild type level in the presence of CCCP, an energy uncoupler altering the energy of the drug efflux pump. Conclusion The 14 RND pumps gene we have identified in the genome of B. cenocepacia suggest that active efflux could be a major mechanism underlying antimicrobial resistance in this microorganism. We have characterized the ORF2 pump, one of these 14 potential RND efflux systems. Its overexpression in E. coli conferred resistance to several antibiotics and to ethidium bromide but it remains to be determined if this pump play a significant role in the antimicrobial intrinsic resistance of B. cenocepacia. The characterization of antibiotic efflux pumps in B

  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

    From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin...... (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....... Resistance to sulphametazole increased from 17% in 1996 to 30% in 1998 but has since decreased to 4% in 2001. Resistance to trimethoprim increased to 51% in 1997 and decreased to 21% in 2001. Resistance to tetracycline (21-31%) remained relatively constant during 1996-2000, but increased to 47% in 2001...

  4. Prevalence and characterization of plasmids carrying sulfonamide resistance genes among Escherichia coli from pigs, pig carcasses and human.

    Science.gov (United States)

    Wu, Shuyu; Dalsgaard, Anders; Hammerum, Anette M; Porsbo, Lone J; Jensen, Lars B

    2010-07-30

    Sulfonamide resistance is very common in Escherichia coli. The aim of this study was to characterize plasmids carrying sulfonamide resistance genes (sul1, sul2 and sul3) in E. coli isolated from pigs and humans with a specific objective to assess the genetic diversity of plasmids involved in the mobility of sul genes. A total of 501 E. coli isolates from pig feces, pig carcasses and human stools were tested for their susceptibility to selected antimicrobial. Multiplex PCR was conducted to detect the presence of three sul genes among the sulfonamide-resistant E. coli isolates. Fifty-seven sulfonamide-resistant E. coli were selected based on presence of sul resistance genes and subjected to conjugation and/or transformation experiments. S1 nuclease digestion followed by pulsed-field gel electrophoresis was used to visualize and determine the size of plasmids. Plasmids carrying sul genes were characterized by PCR-based replicon typing to allow a comparison of the types of sul genes, the reservoir and plasmid present. A total of 109/501 isolates exhibited sulfonamide resistance. The relative prevalences of sul genes from the three reservoirs (pigs, pig carcasses and humans) were 65%, 45% and 12% for sul2, sul1, and sul3, respectively. Transfer of resistance through conjugation was observed in 42/57 isolates. Resistances to streptomycin, ampicillin and trimethoprim were co-transferred in most strains. Class 1 integrons were present in 80% of sul1-carrying plasmids and 100% of sul3-carrying plasmids, but only in 5% of sul2-carrying plasmids. The sul plasmids ranged from 33 to 160-kb in size and belonged to nine different incompatibility (Inc) groups: FII, FIB, I1, FIA, B/O, FIC, N, HI1 and X1. IncFII was the dominant type in sul2-carrying plasmids (52%), while IncI1 was the most common type in sul1 and sul3-carrying plasmids (33% and 45%, respectively). Multireplicons were found associated with all three sul genes. Sul genes were distributed widely in E. coli isolated

  5. Prevalence and characterization of plasmids carrying sulfonamide resistance genes among Escherichia coli from pigs, pig carcasses and human

    Directory of Open Access Journals (Sweden)

    Hammerum Anette M

    2010-07-01

    Full Text Available Abstract Background Sulfonamide resistance is very common in Escherichia coli. The aim of this study was to characterize plasmids carrying sulfonamide resistance genes (sul1, sul2 and sul3 in E. coli isolated from pigs and humans with a specific objective to assess the genetic diversity of plasmids involved in the mobility of sul genes. Methods A total of 501 E. coli isolates from pig feces, pig carcasses and human stools were tested for their susceptibility to selected antimicrobial. Multiplex PCR was conducted to detect the presence of three sul genes among the sulfonamide-resistant E. coli isolates. Fifty-seven sulfonamide-resistant E. coli were selected based on presence of sul resistance genes and subjected to conjugation and/or transformation experiments. S1 nuclease digestion followed by pulsed-field gel electrophoresis was used to visualize and determine the size of plasmids. Plasmids carrying sul genes were characterized by PCR-based replicon typing to allow a comparison of the types of sul genes, the reservoir and plasmid present. Results A total of 109/501 isolates exhibited sulfonamide resistance. The relative prevalences of sul genes from the three reservoirs (pigs, pig carcasses and humans were 65%, 45% and 12% for sul2, sul1, and sul3, respectively. Transfer of resistance through conjugation was observed in 42/57 isolates. Resistances to streptomycin, ampicillin and trimethoprim were co-transferred in most strains. Class 1 integrons were present in 80% of sul1-carrying plasmids and 100% of sul3-carrying plasmids, but only in 5% of sul2-carrying plasmids. The sul plasmids ranged from 33 to 160-kb in size and belonged to nine different incompatibility (Inc groups: FII, FIB, I1, FIA, B/O, FIC, N, HI1 and X1. IncFII was the dominant type in sul2-carrying plasmids (52%, while IncI1 was the most common type in sul1 and sul3-carrying plasmids (33% and 45%, respectively. Multireplicons were found associated with all three sul genes

  6. Susceptibility Profiles of Mycobacterium ulcerans Isolates to Streptomycin and Rifampicin in Two Districts of the Eastern Region of Ghana

    Directory of Open Access Journals (Sweden)

    Enid Owusu

    2016-01-01

    Full Text Available Background. Drug resistance is a major challenge in antibiotic chemotherapy. Assessing resistance profiles of pathogens constitutes an essential surveillance tool in the epidemiology and control of infectious diseases, including Buruli ulcer (BU disease. With the successful definitive management of BU using rifampicin and streptomycin, little attention had been paid to monitoring emergence of resistant Mycobacterium ulcerans (M. ulcerans isolates in endemic communities. This study investigated the susceptibility profiles of M. ulcerans isolates from two BU endemic areas in Ghana to streptomycin and rifampicin. Methods. The antibiotic susceptibility of seventy (70 M. ulcerans isolates to rifampicin and streptomycin was determined simultaneously at critical concentrations of 40 µg/mL and 4 µg/mL, respectively, by the Canetti proportion method. Results. Resistance to rifampicin was observed for 12 (17.1% M. ulcerans isolates tested, whilst 2 (2.9% showed resistance to streptomycin. None of the isolates tested showed dual resistance to both rifampicin and streptomycin. Conclusion. Outcomes from this study may not be reflective of all BU endemic communities; it, however, provides information on the resistance status of the isolates, which is useful for monitoring of M. ulcerans, as well as BU disease surveillance and control.

  7. Molecular characterization of antimicrobial resistance in enterococci and Escherichia coli isolates from European wild rabbit (Oryctolagus cuniculus).

    Science.gov (United States)

    Silva, Nuno; Igrejas, Gilberto; Figueiredo, Nicholas; Gonçalves, Alexandre; Radhouani, Hajer; Rodrigues, Jorge; Poeta, Patrícia

    2010-09-15

    A total of 44 Escherichia coli and 64 enterococci recovered from 77 intestinal samples of wild European rabbits in Portugal were analyzed for resistance to antimicrobial agents. Resistance in E. coli isolates was observed for ampicillin, tetracycline, sulfamethoxazole/trimethoprim, streptomycin, gentamicin, tobramycin, nalidixic acid, ciprofloxacin and chloramphenicol. None of the E. coli isolates produced extended-spectrum beta-lactamases (ESBLs). The bla(TEM), aadA, aac(3)-II, tet(A) and/or tet(B), and the catA genes were demonstrated in all ampicillin, streptomycin, gentamicin, tetracycline, and chloramphenicol-resistant isolates respectively, and the sul1 and/or sul2 and/or sul3 genes in 4 of 5 sulfamethoxazole/trimethoprim resistant isolates. Of the enterococcal isolates, Enterococcus faecalis was the most prevalent detected species (39 isolates), followed by E. faecium (21 isolates) and E. hirae (4 isolates). More than one-fourth (29.7%) of the isolates were resistant to tetracycline; 20.3% were resistant to erythromycin, 14.1% were resistant to ciprofloxacin and 10.9% were resistant to high-level-kanamycin. Lower level of resistance (streptomycin. No vancomycin-resistance was detected in the enterococci isolates. Resistance genes detected included aac(6')-aph(2''), ant(6)-Ia, tet(M) and/or tet(L) in all gentamicin, streptomycin and tetracycline-resistant isolates respectively. The aph(3')-IIIa gene was detected in 6 of 7 kanamycin-resistant isolates, the erm(B) gene in 11 of 13 erythromycin-resistant isolates and the vat(D) gene in the quinupristin/dalfopristin-resistant E. faecium isolate. This survey showed that faecal bacteria such as E. coli and enterococci of wild rabbits could be a reservoir of antimicrobial resistance genes. Copyright 2010 Elsevier B.V. All rights reserved.

  8. Antimicrobial resistance, virulence genes and PFGE-profiling of Escherichia coli isolates from South Korean cattle farms.

    Science.gov (United States)

    Shin, Seung Won; Byun, Jae-Won; Jung, Myounghwan; Shin, Min-Kyoung; Yoo, Han Sang

    2014-09-01

    To estimate the prevalence of Escherichia coli with potential pathogenicity in cattle farm in South Korea, a total of 290 E. coli isolates were isolated from cattle farms over a period of 2 years in South Korea. These were examined for phenotypic and genotypic characteristics including antimicrobial susceptibility, serotype, and gene profiles of virulence and antimicrobial resistance. The most dominant virulence gene was f17 (26.2%), followed by stx2 (15.9%), ehxA (11.0%), stx1 (8.3%), eae (5.2%), and sta (4.1%). Some shiga-toxin producing E. coli isolates possessed eae (15.9%). All isolates except for one showed resistance to one or more antimicrobials, with 152 isolates exhibiting multidrug-resistance. The most prevalent resistance phenotype detected was streptomycin (63.1%), followed by tetracycline (54.5%), neomycin (40.3%), cephalothin (32.8%), amoxicillin (30.0%), ampicillin (29.7%), and sulphamethoxazole/trimethoprim (16.6%). The associated resistance determinants detected were strA-strB (39.0%), tet(E) (80.0%), tet(A) (27.6%), aac(3)-IV (33.1%), aphA1 (21.4%), bla TEM (23.8%), and sul2 (22.1%). When investigated by O serotyping and PFGE molecular subtyping, the high degree of diversity was exhibited in E. coli isolates. These results suggest that E. coli isolates from South Korean cattle farms are significantly diverse in terms of virulence and antimicrobial resistance. In conclusion, the gastroinstestinal flora of cattle could be a significant reservoir of diverse virulence and antimicrobial resistance determinants, which is potentially hazardous to public health.

  9. Diversity of β-lactamase-encoding genes among Gram-negative isolates from water samples in Northern Portugal

    OpenAIRE

    Manageiro, Vera; Ferreira, Eugénia; Figueira, Vânia; Manaia, Célia M.; Caniça, Manuela

    2012-01-01

    Water has been recognized as a reservoir for antibiotic resistance genes (ARG), where the presence of mobile genetic elements, including plasmids, favors their dissemination. It is noteworthy that non- pathogenic environmental organisms, where plasmids encoding multiple ARG are prevalent, can provide resistance to most classes of antimicrobials including :-lactams, aminoglycosides, chloramphenicol, trimethoprim, streptomycin, fosfomycin, q...

  10. 21 CFR 520.2158a - Streptomycin sulfate oral solution.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Streptomycin sulfate oral solution. 520.2158a... Streptomycin sulfate oral solution. (a) Specifications. Solution containing 25 percent streptomycin sulfate. (b... administer for more than 4 days. Prepare fresh solution daily. Calves: Withdraw 2 days before slaughter. As...

  11. Frequency of antimicrobial resistance and integron gene cassettes in Escherichia coli isolated from giant pandas (Ailuropoda melanoleuca) in China.

    Science.gov (United States)

    Zou, Wencheng; Li, Caiwu; Yang, Xin; Wang, Yongxiang; Cheng, Guangyang; Zeng, Jinxin; Zhang, Xiuzhong; Chen, Yanpeng; Cai, Run; Huang, Qianru; Feng, Lan; Wang, Hongning; Li, Desheng; Zhang, Guiquan; Chen, Yanxi; Zhang, Zhizhong; Zhang, Heming

    2018-03-01

    Escherichia coli (E. coli) is considered as a common opportunistic pathogen, which causes seriously intestinal infections to giant pandas (Ailuropoda melanoleuca) and other animals. The aim of this investigation was to characterize the antimicrobial resistance and integron gene cassettes in E. coli isolated from the faeces of giant pandas in China. A total of 89 E. coli were isolated, after diagnosis of isolates and genomes were extracted. All the isolates were screened for the presence of related drug-resistance genes and integron gene cassettes through the Polymerase Chain Reaction (PCR) and sequencing. In addition, antimicrobial resistance testing was performed according to the standard disk diffusion method (CLSI 2013). The results demonstrated that all the isolates were multi-drug resistance (MDR). High resistance proportions of the E. coli isolates were to streptomycin (93%), cefazolin (90%), amikacin (75%), tetracycline (65%), ampicillin (62%), cefotaxime and trimethoprim-sulfamethoxazole (54%, each). With respect to the various resistance genes; bla CTX-M , sul1, ant (3')-Ia, tetA, qnrB, tetE, floR, aac (6')-Ib, sul2, rmtA, cmlA, rmtB and tetC were identified with the respective frequencies of 44%, 45%, 38%, 37%, 35%, 27%, 26%, 20%, 18%, 15%, 10%, 7% and 4%. None of the isolates was positive for qnrA and cfr genes. Moreover, a further investigation of integron revealed that the emergence of class 1 and 2 integrons were in 47% and 8% isolates, respectively. While class 3 integron was not screened. Six types of containing in class 1 integron specific gene cassettes (dfrA12-orfF-aadA2, dfrA17-aadA5, aadA1, aadA5, dfrA1 and dfrA7) were identified. However, only one gene cassette (dfrA1-sat2-aadA1) was detected in class 2 integron. These finding emphasize that a high level of E. coli isolates harbored antibiotics resistance and integron gene cassettes, which may bring so many potential threats to the health of giant pandas. Copyright © 2018 Elsevier Ltd. All

  12. [Establishment of 5 resistant ovarian cancer cell strains and expression of resistance-related genes].

    Science.gov (United States)

    Luan, Ying-zi; Li, Li; Li, Dang-rong; Zhang, Wei; Tang, Bu-jian

    2004-06-01

    To investigate expression difference of several drug resistance related genes between sensitive and resistant ovarian carcinoma cells. Cell lines resistant to cisplatin, carboplatin and taxol were established from ovarian carcinoma cell lines of SKOV3 and A2780, and their biological features were detected. The expressions of several genes related to drug resistance were measured by RT-PCR method. (1) The values of resistance index (RI) of resistant cells to relevant drugs were elevated 3 times or more, with different degrees of cross-resistance to several other drugs (RI 2 approximately 20). They grew more slowly than primary cells (Td elongated 1.4 approximately 2.4 times, P 0.05). Intracellular concentrations of relevant drugs were reduced 2.0 approximately 8.5 times in resistant cells (P p53, lung resistance protein-1 (LRP-1), multiple drug resistance related protein-1 (MRP-1) genes were expressed at lower levels in resistant cells than in sensitive cells; while protein kinase C (PKC), topoisomerase (topo) I, and topo II beta were expressed higher, no obvious alterations were found concerning glutathione S transferase-pi (GST-pi), and topo II alpha. Expression of multiple drug resistance-1 (MDR-1) gene was either elevated or reduced in different cells. The expressions of resistance related genes were widely different in different kinds of resistant cells, suggesting more than one pathway leading to resistance transformation. This adds more difficulties for clinical management.

  13. Mutations in the 915 region of Escherichia coli 16S ribosomal RNA reduce the binding of streptomycin to the ribosome.

    Science.gov (United States)

    Leclerc, D; Melançon, P; Brakier-Gingras, L

    1991-01-01

    The nine possible single-base substitutions were produced at positions 913 to 915 of the 16S ribosomal RNA of Escherichia coli, a region known to be protected by streptomycin [Moazed, D. and Noller, H.F. (1987) Nature, 327, 389-394]. When the mutations were introduced into the expression vector pKK3535, only two of them (913A----G and 915A----G) permitted recovery of viable transformants. Ribosomes were isolated from the transformed bacteria and were assayed for their response to streptomycin in poly(U)- and MS2 RNA-directed assays. They were resistant to the stimulation of misreading and to the inhibition of protein synthesis by streptomycin, and this correlated with a decreased binding of the drug. These results therefore demonstrate that, in line with the footprinting studies of Moazed and Noller, mutations in the 915 region alter the interaction between the ribosome and streptomycin. PMID:1713666

  14. Cross-linking of streptomycin to the 16S ribosomal RNA of Escherichia coli

    International Nuclear Information System (INIS)

    Gravel, M.; Melancon, P.; Barkier-Gingras, L.

    1987-01-01

    [ 3 H]Dihydrostreptomycin was cross-linked to the 30S ribosomal subunit from Escherichia coli with the bifunctional reagent nitrogen mustard. The cross-linking primarily involved the 16S RNA. To localize the site of cross-linking of streptomycin to the 16S RNA, the authors hybridized RNA labeled with streptomycin to restriction fragments of the 16S RNA gene. Labeled RNA hybridized to DNA fragments corresponding to bases 892-917 and bases 1394-1415. These two segments of the ribosomal RNA must by juxtaposed in the ribosome, since there is a single binding site for streptomycin. This region has been implicated both in the decoding site and in the binding of initiation factor IF-3, indicating its functional importance

  15. Microarray-based Detection of Antibiotic Resisteance Genes in Salmonella

    NARCIS (Netherlands)

    Hoek, van A.H.A.M.; Aarts, H.J.M.

    2008-01-01

    In the presented study, 143 Salmonella isolates belonging to 26 different serovars were screened for the presence of antibiotic resistance genes by microarray analysis. The microarray contained a total of 223 oligonucleotides representing genes encoding for resistance to the following antibiotic

  16. Gene interactions and genetics of blast resistance and yield ...

    Indian Academy of Sciences (India)

    2016-08-26

    Oryza sativa L.) ... four blast resistance genes Pi1, Pi2, Pi33 and Pi54 in combination were used to study the nature and magnitude of gene action for disease resistance and yield attributes. ... Please take note of this change.

  17. 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 ...

  18. Codon-optimized antibiotic resistance gene improves efficiency of ...

    Indian Academy of Sciences (India)

    Success rate of transient transformation and cell growth in selective culture were significantly increased by use of fgmR instead of a native gentamicin resistance gene, suggesting that codon optimization improved translation efficiency of the marker gene and increased antibiotic resistance. Our result shows that similarity in ...

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

    Indian Academy of Sciences (India)

    Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome. 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS ...

  20. Genome scanning for identification of resistance gene analogs (RGAs)

    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 ...

  1. New resistance genes in the Zea mays: exserohilum turcicum pathosystem

    Directory of Open Access Journals (Sweden)

    Juliana Bernardi Ogliari

    2005-09-01

    Full Text Available The use of monogenic race-specific resistance is widespread for the control of maize (Zea mays L. helminthosporiosis caused by Exserohilum turcicum. Inoculation of 18 Brazilian isolates of E. turcicum onto elite maize lines containing previously identified resistance genes and onto differential near-isogenic lines allowed the identification of new qualitative resistance genes. The inoculation of one selected isolate on differential near-isogenic lines, F1 generations and a BC1F1 population from the referred elite lines enabled the characterization of the resistance spectrum of three new genes, one dominant (HtP, one recessive (rt and a third with non-identified genetic action. Three physiological races of the pathogen were also identified including two with new virulence factors capable of overcoming the resistance of one of the resistance genes identified here (rt.

  2. Characterization of antimicrobial resistance patterns and class 1 integrons in Escherichia coli O26 isolated from humans and animals.

    Science.gov (United States)

    Srinivasan, Velusamy; Gillespie, Barbara E; Nguyen, Lien T; Headrick, Susan I; Murinda, Shelton E; Oliver, Stephen P

    2007-03-01

    Antimicrobial resistance patterns and the prevalence of antimicrobial resistance genes and class 1 integrons in 35 Escherichia coli O26 isolated from humans and food-producing animals were evaluated. All isolates were resistant to cefaclor, cefalothin and sulfonamide and were susceptible to amikacin, gentamicin, cefmetazole, cefotaxime, ceftriaxone, ciprofloxacin, norfloxacin and trimethoprim. Most isolates were resistant to aztreonam, ampicillin, tetracycline, streptomycin and kanamycin. All ampicillin- and streptomycin-resistant E. coli O26 carried ampC and strA-strB gene sequences, respectively. Florfenicol- and chloramphenicol-resistant isolates carried floR but not cmlA. Class1 integrons were identified in 14% of E. coli O26 isolates. To our knowledge, this is the first report describing the presence of multiple antimicrobial resistance genes in E. coli O26 isolated from human and animal origins.

  3. Cholera in Vietnam: Changes in Genotypes and Emergence of Class I Integrons Containing Aminoglycoside Resistance Gene Cassettes in Vibrio cholerae O1 Strains Isolated from 1979 to 1996

    Science.gov (United States)

    Dalsgaard, A.; Forslund, A.; Tam, N. V.; Vinh, D. X.; Cam, P. D.

    1999-01-01

    The number of cholera cases and the mortality rates reported from different regions of Vietnam varied considerably in the period from 1979 to 1996, with between 2,500 and 6,000 cases reported annually from 1992 to 1995. Annual mortality rates ranged from 2.0 to 9.6% from 1979 to 1983 to less than 1.8% after 1983. Major cholera outbreaks were reported from the High Plateau region for the first time in 1994 and 1995; this is an area with limited access to health services and safe drinking-water supplies. All cases were associated with Vibrio cholerae O1. Using ribotyping, cholera toxin (CT) genotyping, and characterization of antibiotic susceptibility patterns and antibiotic resistance genes by PCR, we show that strains isolated after 1990 were clearly different from strains isolated before 1991. In contrast to strains isolated before 1991, 94% of 104 strains isolated after 1990 showed an identical ribotype R1, were resistant to sulfamethoxazole and streptomycin, and showed a different CT genotype. Furthermore, PCR analysis revealed that sulfamethoxazole-resistant strains harbored class I integrons containing a gene cassette ant(3")-1a encoding resistance to streptomycin and spectinomycin. This is, to our knowledge, the first report of class I integrons in V. cholerae. The development of cholera and the changes in the phenotypic and genotypic properties of V. cholerae O1 shown in the present study highlight the importance of monitoring V. cholerae O1 in Vietnam as in other parts of the world. In particular, the emergence of the new ribotype R1 strain containing class I integrons should be further studied. PMID:9986842

  4. 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

    Objectives: To determine the occurrence of class 1 and 2 integrons and antimicrobial resistance genes among sulphonamide-resistant Shigella strains isolated in Brazil during 1999-2003. Methods: Sixty-two Shigella (Shigella flexneri, n = 47 and Shigella sonnei, n = 15) were tested against 21....... Conclusions: The detection of class 1 and 2 integrons and additional antimicrobial resistance genes allowed us to identify the most frequent antimicrobial resistance patterns of Shigella spp. isolated in Brazil....

  5. Barley Stem Rust Resistance Genes: Structure and Function

    Directory of Open Access Journals (Sweden)

    Andris Kleinhofs

    2009-07-01

    Full Text Available Rusts are biotrophic pathogens that attack many plant species but are particularly destructive on cereal crops. The stem rusts (caused by have historically caused severe crop losses and continue to threaten production today. Barley ( L. breeders have controlled major stem rust epidemics since the 1940s with a single durable resistance gene . As new epidemics have threatened, additional resistance genes were identified to counter new rust races, such as the complex locus against races QCCJ and TTKSK. To understand how these genes work, we initiated research to clone and characterize them. The gene encodes a unique protein kinase with dual kinase domains, an active kinase, and a pseudokinase. Function of both domains is essential to confer resistance. The and genes are closely linked and function coordinately to confer resistance to several wheat ( L. stem rust races, including the race TTKSK (also called Ug99 that threatens the world's barley and wheat crops. The gene encodes typical resistance gene domains NBS, LRR, and protein kinase but is unique in that all three domains reside in a single gene, a previously unknown structure among plant disease resistance genes. The gene encodes an actin depolymerizing factor that functions in cytoskeleton rearrangement.

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

    African Journals Online (AJOL)

    Antimicrobial susceptibility testing among the isolates showed resistance to amoxicillin (92%), amoxicillin-clavulanic acid (84.4%), tetracycline (71.4%), gentamycin (43.5%), nalidixic acid (38.3%) and nitrofurantoin (7.9%). E. coli showed the highest resistance to most of the antibiotics. Tetracycline resistance gene was ...

  7. Complex Interactions between Fungal Avirulence Genes and Their Corresponding Plant Resistance Genes and Consequences for Disease Resistance Management

    Directory of Open Access Journals (Sweden)

    Yohann Petit-Houdenot

    2017-06-01

    Full Text Available During infection, pathogens secrete an arsenal of molecules, collectively called effectors, key elements of pathogenesis which modulate innate immunity of the plant and facilitate infection. Some of these effectors can be recognized directly or indirectly by resistance (R proteins from the plant and are then called avirulence (AVR proteins. This recognition usually triggers defense responses including the hypersensitive response and results in resistance of the plant. R—AVR gene interactions are frequently exploited in the field to control diseases. Recently, the availability of fungal genomes has accelerated the identification of AVR genes in plant pathogenic fungi, including in fungi infecting agronomically important crops. While single AVR genes recognized by their corresponding R gene were identified, more and more complex interactions between AVR and R genes are reported (e.g., AVR genes recognized by several R genes, R genes recognizing several AVR genes in distinct organisms, one AVR gene suppressing recognition of another AVR gene by its corresponding R gene, two cooperating R genes both necessary to recognize an AVR gene. These complex interactions were particularly reported in pathosystems showing a long co-evolution with their host plant but could also result from the way agronomic crops were obtained and improved (e.g., through interspecific hybridization or introgression of resistance genes from wild related species into cultivated crops. In this review, we describe some complex R—AVR interactions between plants and fungi that were recently reported and discuss their implications for AVR gene evolution and R gene management.

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

    Indian Academy of Sciences (India)

    PUNEET INDER TOOR

    end of 5DS linked with a group of four colocated SSRs and two resistance gene analogue (RGA)-STS markers at a distance of 5.3 cM. ... and LrAc appear to be the candidate genes for marker-assisted enrichment of the wheat gene pool for rust resistance. [Toor P. I., Kaur S., Bansal ..... stocks with reduced alien chromatin.

  9. Molecular detection of virulence genes and multi-drug resistance patterns in Escherichia coli (STEC) in clinical bovine mastitis: Alborz province, Iran.

    Science.gov (United States)

    Tavakoli, M; Pourtaghi, H

    2017-01-01

    The aim of this study was to identify virulence genes and antimicrobial resistance of Escherichia coli isolated from bovine clinical mastitis in dairy herds in Iran. Sampling was done from 86 inflamed quarters of dairy cows in 8 commercial farms of Alborz province, Iran in summer 2015. Shiga toxin-producing E. coli (STEC) virulence genes were detected by multiplex PCR and multi-drug resistance profiles were confirmed using disk diffusion method. Among 60 E. coli isolated from examined samples, 13 (21.6%) of them were STEC. The results of PCR assay showed that eaeA gene was carried by 4 (30.8%) of STEC isolates. Although stx1 in combination with eaeA gene was detected from 7 (53.8%) of STEC isolates, stx1 and stx2 genes were detected from only 1 (7.7%) of the examined samples. The result of the disk diffusion method showed that all E. coli isolates were resistant to penicillin, tylosin, oxytetracycline, erythromycin, ampicillin, streptomycin and neomycin. However all isolates were susceptible to enrofloxacin. Therefore, according to the results establishing a regular monitoring system for identification of cases with clinical mastitis and conducting antibiotic sensitivity tests are recommended.

  10. Overexpression of antibiotic resistance genes in hospital effluents over time.

    Science.gov (United States)

    Rowe, Will P M; Baker-Austin, Craig; Verner-Jeffreys, David W; Ryan, Jim J; Micallef, Christianne; Maskell, Duncan J; Pearce, Gareth P

    2017-06-01

    Effluents contain a diverse abundance of antibiotic resistance genes that augment the resistome of receiving aquatic environments. However, uncertainty remains regarding their temporal persistence, transcription and response to anthropogenic factors, such as antibiotic usage. We present a spatiotemporal study within a river catchment (River Cam, UK) that aims to determine the contribution of antibiotic resistance gene-containing effluents originating from sites of varying antibiotic usage to the receiving environment. Gene abundance in effluents (municipal hospital and dairy farm) was compared against background samples of the receiving aquatic environment (i.e. the catchment source) to determine the resistome contribution of effluents. We used metagenomics and metatranscriptomics to correlate DNA and RNA abundance and identified differentially regulated gene transcripts. We found that mean antibiotic resistance gene and transcript abundances were correlated for both hospital ( ρ  = 0.9, two-tailed P  resistance genes ( bla GES and bla OXA ) were overexpressed in all hospital effluent samples. High β-lactam resistance gene transcript abundance was related to hospital antibiotic usage over time and hospital effluents contained antibiotic residues. We conclude that effluents contribute high levels of antibiotic resistance genes to the aquatic environment; these genes are expressed at significant levels and are possibly related to the level of antibiotic usage at the effluent source. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

  11. 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 ...

  12. Associations between Antimicrobial Resistance Phenotypes, Antimicrobial Resistance Genes, and Virulence Genes of Fecal Escherichia coli Isolates from Healthy Grow-Finish Pigs ▿

    OpenAIRE

    Rosengren, Leigh B.; Waldner, Cheryl L.; Reid-Smith, Richard J.

    2009-01-01

    Escherichia coli often carries linked antimicrobial resistance genes on transmissible genetic elements. Through coselection, antimicrobial use may select for unrelated but linked resistance or virulence genes. This study used unconditional statistical associations to investigate the relationships between antimicrobial resistance phenotypes and antimicrobial resistance genes in 151 E. coli isolates from healthy pigs. Phenotypic resistance to each drug was significantly associated with phenotyp...

  13. Codon-optimized antibiotic resistance gene improves efficiency of ...

    Indian Academy of Sciences (India)

    2013-10-01

    Oct 1, 2013 ... native gentamicin resistance gene, suggesting that codon optimization improved translation efficiency of the marker gene and ... to be taken into account when exogenous transgenes are expressed in Frankia cells. [Kucho K, Kakoi K, ..... gene coding for the green fluorescent protein (GFP) is a versatile ...

  14. The cfr and cfr-like multiple resistance genes

    DEFF Research Database (Denmark)

    Vester, Birte

    2018-01-01

    . The cfr gene is found in various bacteria in many geographical locations and placed on plasmids or associated with transposons. Cfr-related genes providing similar resistance have been identified in Bacillales, and now also in the pathogens Clostridium difficile and Enterococcus faecium. In addition......, the presence of the cfr gene has been detected in harbours and food markets....

  15. Linking microbial community structure and function to characterize antibiotic resistant bacteria and antibiotic resistant genes from cattle feces

    Science.gov (United States)

    There is widespread interest in monitoring the development of antibiotic resistant bacteria and antibiotic resistance genes in agriculturally impacted environments, however little is known about the relationships between bacterial community structure, and antibiotic resistance gene profiles. Cattl...

  16. 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.

  17. Mobile antibiotic resistance - the spread of genes determining the resistance of bacteria through food products.

    Science.gov (United States)

    Godziszewska, Jolanta; Guzek, Dominika; Głąbski, Krzysztof; Wierzbicka, Agnieszka

    2016-07-07

    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.

  18. Determination of rust resistance genes in pakistani bread wheats

    International Nuclear Information System (INIS)

    Qamar, M.; Ahmad, S.D.; Rabbani, M.A.; Shinwari, Z.K.

    2014-01-01

    Stripe and leaf rusts are the major constraints to bread wheat production in Pakistan. Molecular markers were used to investigate the presence of leaf rust and stripe rust resistance gene cluster Lr34/Yr18 and stem rust resistance gene Sr2 in 52 Pakistani bread wheat cultivars/lines. PCR amplification of DNA fragments using DNA marker csLV-34 showed that 13 of the studied cultivars/lines, namely 03FJ26, NR 337, NR 339, NR 347, NR 350, Manthar, Margalla 99, Iqbal 2000, Saleem 2000, Wafaq 2001, Marwat 2001, Pirsabak 2004 and Fareed 2006 carry leaf rust and stripe rust resistance genes Lr34/Yr18. Stem rust resistance gene Sr2 was observed in 36 Pakistani spring wheat cultivars/lines using stm560.3tgag marker. The slow rusting gene Sr2 needs to be combined with additional stem rust resistance genes to establish durable resistance against Ug99 in modern wheat cultivars. Low frequency of Lr34/Yr18 was found in Pakistani wheats. This gene cluster needs to be incorporated into Pakistani wheats for durable rust resistance. (author)

  19. Diversity analysis of streptomycetes and associated phosphotranspherase genes in soil.

    Directory of Open Access Journals (Sweden)

    Paris Laskaris

    Full Text Available An attempt was made to verify the observation that Streptomyces griseus was prevalent in soil based on isolation work. A genus-specific PCR was developed for Streptomyces based on the housekeeping gene atpD and used to investigate species diversity within selected soils. The presence of S. griseus was investigated to determine coexistence of resistance-only streptomycin phosphotransferase (strA in the same soil as streptomycin producers. Two additional PCR-based assays were developed; one specific for strA in association with production, the other for more diverse strA and other related phosphotranferases. Both the S. griseus atpD and strA genes were below the PCR detection limit in all soils examined. A number of more diverse phosphotransferase genes were amplified, a minority of which may be associated with streptomycin production. We conclude that neither streptomycin producers nor S. griseus are prevalent in the fresh or chitin and starch-amended soils examined (less than 0.1% of soil actinobacteria. One of the soil sites had received plantomycin (active ingredient: streptomycin and diversity studies suggested that this altered the streptomycete populations present in the soil.

  20. Synergy among thymol, eugenol, berberine, cinnamaldehyde and streptomycin against planktonic and biofilm-associated food-borne pathogens.

    Science.gov (United States)

    Liu, Q; Niu, H; Zhang, W; Mu, H; Sun, C; Duan, J

    2015-05-01

    Essential oils have been found to exert antibacterial, antifungal, spasmolytic, and antiplasmodial activity and therapeutic effect in cancer treatment. In this study, the antibacterial activities of four main essential oils' components (thymol (Thy), eugenol (Eug), berberine (Ber), and cinnamaldehyde (Cin)) were evaluated against two food-borne pathogens, Listeria monocytogenes and Salmonella Typhimurium, either alone or in combination with streptomycin. Checkerboard assay demonstrated that Thy and Cin elicited a synergistic effect with streptomycin against L. monocytogenes, while a synergy existed between Cin or Eug and streptomycin against Salm. Typhimurium. Further experiments showed that this synergy was sufficient to eradicate biofilms formed by these two bacteria. Thus, our data highlighted that the combinations of specific components from essential oils and streptomycin were useful for the treatment of food-borne pathogens, which might help prevent the spread of antibiotic resistance through improving antibiotic effectiveness. This study has shown the synergistic effect of four components of essential oil (thymol, eugenol, berberine and cinnamaldehyde) combined with streptomycin on planktonic and biofilm-associated food-borne pathogens Listeria monocytogenes and Salmonella Typhimurium. These findings indicate that combination of specific components of essential oils with streptomycin may provide alternative methods to overcome the problem of food-borne bacteria both in suspension and in biofilm. © 2015 The Society for Applied Microbiology.

  1. Coupling of rates of transcription, translation, and messenger ribonucleic acid degradation in streptomycin-dependent mutants of Escherichia coli.

    Science.gov (United States)

    Gupta, R S; Schlessinger, D

    1976-01-01

    The growth rates of streptomycin-dependent mutants varied in proportion to the level of streptomycin supplied; growth also varied characteristically from one dependent strain to another at a given streptomycin concentration. When cells growing at different rates (over a threefold range) were treated with rifampin, direct proportionality was observed for three parameters: (i) the rates of shutoff of transcription of total ribonucleic acid (RNA) and ribosomal RNA, as measured by pulse labeling at later times; (ii) the translation time for molecules of beta-galactosidase; and (iii) the rate of chemical degradation of messenger RNA. In contrast, the rate of functional inactivation of both total and beta-galactosidase messenger RNA was about the same at all growth rates. None of the variations of growth or other parameters were observed in an otherwise isogenic streptomycin-resistant strain treated with streptomycin. Since the mutational change in strd mutants and the site of action of streptomycin are in the 30S ribosomal subunits, it is suggested that the rate of ribosome function is set by the dependent lesion (and the level of streptomycin). One possibility is that the other correlated effects are mechanistically "coupled" to ribosome function, but the apparent coupling could also be an indirect result of differential effects of streptomycin on variables such as ribosomal miscoding and nucleotide pool size. However, since the rate of functional inactivation of messenger RNA is constant even when the RNA is broken down two- to fourfold more slowly, translation yield tends to be proportional to the growth rate of the dependent strains.

  2. Control of fire blight (Erwinia amylovora) on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes.

    Science.gov (United States)

    Aćimović, Srđan G; Zeng, Quan; McGhee, Gayle C; Sundin, George W; Wise, John C

    2015-01-01

    Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1-2 apple tree injections of either streptomycin, potassium phosphites (PH), or acibenzolar-S-methyl (ASM), significant reduction of blossom and shoot blight symptoms was observed compared to water injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2, and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR) under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control.

  3. Control of fire blight (Erwinia amylovora on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes

    Directory of Open Access Journals (Sweden)

    Srđan G. Aćimović

    2015-02-01

    Full Text Available Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1-2 apple tree injections of either streptomycin, potassium phosphites (PH or acibenzolar-S-methyl (ASM, significant reduction of blossom and shoot blight symptoms was observed compared to water- or non-injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2 and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control.

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

    Directory of Open Access Journals (Sweden)

    Qing-Bin Yuan

    Full Text Available 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.

  5. 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.

  6. 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 ...

  7. Sponge Microbiota are a Reservoir of Functional Antibiotic Resistance Genes

    DEFF Research Database (Denmark)

    Versluis, Dennis; de Evgrafov, Mari Cristina Rodriguez; Sommer, Morten Otto Alexander

    2016-01-01

    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......). Fifteen of 37 inserts harbored resistance genes that shared 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...

  8. AMINOGLYCOSIDE RESISTANCE GENES IN Pseudomonas aeruginosa ISOLATES FROM CUMANA, VENEZUELA.

    Science.gov (United States)

    Teixeira, Bertinellys; Rodulfo, Hectorina; Carreño, Numirin; Guzmán, Militza; Salazar, Elsa; De Donato, Marcos

    2016-01-01

    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.

  9. Detection of bacterial blight resistance genes in basmati rice landraces.

    Science.gov (United States)

    Ullah, I; Jamil, S; Iqbal, M Z; Shaheen, H L; Hasni, S M; Jabeen, S; Mehmood, A; Akhter, M

    2012-07-20

    Aromatic basmati rice is vulnerable to bacterial blight disease. Genes conferring resistance to bacterial blight have been identified in coarse rice; however, their incorporation into basmati varieties compromises the prized basmati aroma. We identified bacterial blight resistance genes Xa4, xa5, Xa7, and xa13 in 52 basmati landraces and five basmati cultivars using PCR markers. The Xa7 gene was found to be the most prevalent among the cultivars and landraces. The cultivars Basmati-385 and Basmati-2000 also contained the Xa4 gene; however, xa5 and xa13 were confined to landraces only. Ten landraces were found to have multiple resistance genes. Landraces Basmati-106, Basmati-189 and Basmati-208 contained Xa4 and Xa7 genes. Whereas, landraces Basmati-122, Basmati-427, Basmati-433 were observed to have xa5 and Xa7 genes. Landraces Basmati-48, Basmati-51A, Basmati-334, and Basmati-370A possessed Xa7 and xa13 genes. The use of landraces containing recessive genes xa5 and xa13 as donor parents in hybridization with cultivars Basmati-385 and Basmati-2000, which contain the genes Xa4 and Xa7, will expedite efforts to develop bacterial blight-resistant basmati rice cultivars through marker assisted selection, based on a pyramiding approach, without compromising aroma and grain quality.

  10. 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

  11. Concerning Increase in Antimicrobial Resistance in Shiga Toxin-Producing Escherichia coli Isolated from Young Animals during 1980-2016.

    Science.gov (United States)

    Chirila, Flore; Tabaran, Alexandra; Fit, Nicodim; Nadas, George; Mihaiu, Marian; Tabaran, Flaviu; Cătoi, Cornel; Reget, Oana Lucia; Dan, Sorin Daniel

    2017-09-27

    This study was conducted in order to assess the antimicrobial resistance patterns of E. coli isolated from young animals affected between 1980 and 2016. The selected isolates for this study (n=175) carried stx 1 /stx 2 genes and the most prevalent type of pathogenic E. coli found belonged to serogroup O101, antigen (K99)-F41 positive. All STEC-positive isolates were tested for susceptibility to 11 antimicrobials. Multidrug resistance (MDR) increased from 11% during the 1980s to 40% between 2000 and 2016. Resistance to tetracycline and streptomycin was the most frequent co-resistance phenotype (37%). Co-resistance to tetracycline and sulfonamide was found in 21% of E. coli isolates, while the MDR pattern to tetracycline, sulfonamide, and streptomycin was observed in 12% of the strains tested. Only 8% of isolates were co-resistant to tetracycline, ampicillin, streptomycin, and sulfonamide. The most common resistance genes found were those encoding for tetracycline, sulphonamides, and streptomycin, with 54% (n=95) of the tested isolates containing at least one of the genes encoding tetracycline resistance. A total of 87% of E. coli that tested positive for tetracycline (tetA, tetB, and tetC) and sulphonamide (sul1) resistance genes were isolated between 2000 and 2016. A large number of isolates (n=21) carried int1 and a nucleotide sequence analysis revealed that all class 1 integron gene cassettes carried sul1, tet, and dfrA1 resistance genes. An increase was observed in the level of resistance to antimicrobials in Romania, highlighting the urgent need for a surveillance and prevention system for antimicrobial resistance in livestock in Eastern Europe.

  12. Antimicrobial Peptide Resistance Genes in the Plant Pathogen Dickeya dadantii.

    Science.gov (United States)

    Pandin, Caroline; Caroff, Martine; Condemine, Guy

    2016-11-01

    Modification of teichoic acid through the incorporation of d-alanine confers resistance in Gram-positive bacteria to antimicrobial peptides (AMPs). This process involves the products of the dltXABCD genes. These genes are widespread in Gram-positive bacteria, and they are also found in a few Gram-negative bacteria. Notably, these genes are present in all soft-rot enterobacteria (Pectobacterium and Dickeya) whose dltDXBAC operons have been sequenced. We studied the function and regulation of these genes in Dickeya dadantii dltB expression was induced in the presence of the AMP polymyxin. It was not regulated by PhoP, which controls the expression of some genes involved in AMP resistance, but was regulated by ArcA, which has been identified as an activator of genes involved in AMP resistance. However, arcA was not the regulator responsible for polymyxin induction of these genes in this bacterium, which underlines the complexity of the mechanisms controlling AMP resistance in D. dadantii Two other genes involved in resistance to AMPs have also been characterized, phoS and phoH dltB, phoS, phoH, and arcA but not dltD mutants were more sensitive to polymyxin than the wild-type strain. Decreased fitness of the dltB, phoS, and phoH mutants in chicory leaves indicates that their products are important for resistance to plant AMPs. Gram-negative bacteria can modify their lipopolysaccharides (LPSs) to resist antimicrobial peptides (AMPs). Soft-rot enterobacteria (Dickeya and Pectobacterium spp.) possess homologues of the dlt genes in their genomes which, in Gram-positive bacteria, are involved in resistance to AMPs. In this study, we show that these genes confer resistance to AMPs, probably by modifying LPSs, and that they are required for the fitness of the bacteria during plant infection. Two other new genes involved in resistance were also analyzed. These results show that bacterial resistance to AMPs can occur in bacteria through many different mechanisms that need to be

  13. 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-...

  14. Partial inhibition of polysomal ribosomes of Escherichia coli by streptomycin.

    Science.gov (United States)

    Wallace, B J; Tai, P C; Herzog, E L; Davis, B D

    1973-04-01

    With purified initiation-free polysomes of E. coli, whether endogenous or formed in vitro on phage R17 RNA, streptomycin causes partial inhibition of chain elongation. The degree of inhibition is constant over a broad range of streptomycin concentration and decreases markedly with increasing Mg(++) concentration. Hence, streptomycin evidently complexes readily with polysomal ribosomes, causing a partial block in chain elongation. Streptomycin has already been shown to cause a complete block of chain elongation by free ribosomes forming initiation complexes in its presence. The production of a different effect on polysomal ribosomes explains how streptomycin can exert two mutually exclusive effects in cells: phenotypic suppression at low concentrations and irreversible inhibition of protein synthesis at higher concentrations. It also becomes possible to understand why killing by streptomycin is antagonized by agents (such as chloramphenicol) that cause a stable blockade of the ribosomes in polysomes.

  15. Analysis of metal and biocides resistance genes in drug resistance and susceptible Salmonella enterica from food animals

    Science.gov (United States)

    Background Generally drug resistant bacteria carry antibiotic resistance genes and heavy metal and biocide resistance genes on large conjugative plasmids. The presence of these metal and biocide resistance genes in susceptible bacteria are not assessed comprehensively. Hence, WGS data of susceptib...

  16. 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

  17. 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 ...

  18. Prevalence, antibiotic-resistance properties and enterotoxin gene ...

    African Journals Online (AJOL)

    Prevalence, antibiotic-resistance properties and enterotoxin gene profile of Bacillus cereus strains isolated from milk-based baby foods. ... Conclusion: Considerable prevalence of resistant and toxigenic B. cereus and high consumption of milk-based infant foods in Iran, represent an important public health issue which ...

  19. 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

  20. Identification of bacterial blight resistance genes Xa4 in Pakistani ...

    African Journals Online (AJOL)

    Identification of bacterial blight resistance genes Xa4 in Pakistani rice germplasm using PCR. M Arif, M Jaffar, M Babar, MA Sheikh, S Kousar, A Arif, Y Zafar. Abstract. Bacterial blight (BB) caused by Xanthomonas oryzae pv oryzae (Xoo) is a major biotic constraint in the irrigated rice belts. Genetic resistance is the most ...

  1. 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

  2. gene effects for resistance to groundnut rossette disease in exotic ...

    African Journals Online (AJOL)

    ACSS

    2016-02-25

    Feb 25, 2016 ... Opposite and significant signs of dominance [d] and dominance × dominance [l] components indicated the importance of duplicate epitasis in the latter crosses in the control of GRD resistance, which revealed a complex nature of inheritance of GRD resistance. Key Words: Arachis hypogaea, gene effects, ...

  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. Isolation and characterization of a candidate gene for resistance to ...

    African Journals Online (AJOL)

    ARC) domain, and a leucine-rich repeat (LRR) domain, all of which are typical characteristics of resistance genes. We proposed the resistance mechanism of CreV8 based on functional analysis and predictions from its conserved domains and ...

  5. Streptomycin potency is dependent on MscL channel expression

    OpenAIRE

    Iscla, Irene; Wray, Robin; Wei, Shuguang; Posner, Bruce; Blount, Paul

    2014-01-01

    The antibiotic streptomycin is widely used in the treatment of microbial infections. The primary mechanism of action is inhibition of translation by binding to the ribosome, but how it enters the bacterial cell is unclear. Early in the study of this antibiotic, a mysterious streptomycin-induced K+-efflux preceding any decrease in viability was observed; it was speculated that this changed the electrochemical gradient such that streptomycin better accessed the cytoplasm. Here we use a high thr...

  6. Prevalence of aac(6')-Ie-aph(2″)-Ia resistance gene and its linkage to Tn5281 in Enterococcus faecalis and Enterococcus faecium isolates from Tabriz hospitals.

    Science.gov (United States)

    Behnood, Amir; Farajnia, Safar; Moaddab, Seyed Reza; Ahdi-Khosroshahi, Shiva; Katayounzadeh, Aliakbar

    2013-09-01

    High-level gentamicin resistance (HLGR: MIC ≥ 500 µg/ml) in Enterococci is mediated by aminoglycoside modifying enzymes which is mainly encoded by aac(6')-Ie-aph(2″)-Ia gene. The aim of this study was to evaluate the frequency of aac(6')-Ie-aph(2″)-Ia gene in clinical isolates of Enterococcus facium and Enterococcus faecalis collected from hospitals in northwest of Iran. In the present study a total of 111 enterococcus isolates were collected from 4 hospitals during a two year period (July 2009-August 2011). Bacterial identification and species determination were carried out by standard biochemical tests. Antimicrobial susceptibility was evaluated by Kirby Bauer disc diffusion method. MICs were determined by agar dilution method. The frequency of aac(6')-Ie-aph(2″)-Ia gene in the isolates was determined by PCR. The carriage of resistance gene on Tn5281 transposon was identified by long PCR and dot-blot hybridization methods. Antibiotic susceptibility tests revealed that the highest resistance was against streptomycin (74.77%) and erythromycin (67.58%) whereas the highest susceptibility was observed to vancomycin (81.1%). 36 isolates (32.43%) were identified as HLGR, 34(94.44%) of them had resistant gene in their genome. Long PCR studies revealed that 88% of HLGR clinical isolates harboured Tn5281. The aac(6')-Ie-aph(2″)-Ia resistance gene was present on Tn5281 transposon in all 32 isolates according to dot blot hybridization test. The results of this study indicated that aac(6')-Ie-aph(2″)-Ia resistance gene is highly prevalent in gentamicin resistant isolates. Carriage of aac(6')-Ie-aph(2″)-Ia resistance gene on Tn5281 transposable element suggests possible contribution of this transposone on dissemination of resistance gene among enterococcus isolates.

  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. Distribution of Florfenicol Resistance Genes fexA and cfr among Chloramphenicol-Resistant Staphylococcus Isolates

    Science.gov (United States)

    Kehrenberg, Corinna; Schwarz, Stefan

    2006-01-01

    A total of 302 chloramphenicol-resistant Staphylococcus isolates were screened for the presence of the florfenicol/chloramphenicol resistance genes fexA and cfr and their localization on mobile genetic elements. Of the 114 isolates from humans, only a single Staphylococcus aureus isolate showed an elevated MIC to florfenicol, but did not carry either of the known resistance genes, cfr or fexA. In contrast, 11 of the 188 staphylococci from animal sources were considered florfenicol resistant and carried either cfr (one isolate), fexA (five isolates), or both resistance genes (five isolates). In nine cases we confirmed that these genes were carried on a plasmid. Five different types of plasmids could be differentiated on the basis of their sizes, restriction patterns, and resistance genes. The gene fexA, which has previously been shown to be part of the nonconjugative transposon Tn558, was identified in 10 of the 11 resistant isolates from animals. PCR assays were developed to detect different parts of this transposon as well as their physical linkage. Complete copies of Tn558 were found in five different isolates and shown by inverse PCR to be functionally active. Truncated copies of Tn558, in which the tnpA-tnpB area was in part deleted by the integration of a 4,674-bp segment including the gene cfr and a novel 2,446-bp IS21-like insertion sequence, were seen in a plasmid present in three staphylococcal isolates. PMID:16569824

  9. Dissociation of peptidyl-tRNA from ribosomes is perturbed by streptomycin and by strA mutations.

    Science.gov (United States)

    Caplan, A B; Menninger, J R

    1984-01-01

    Peptidyl-tRNA may dissociate preferentially from ribosomes during protein synthesis when it is inappropriate to, does not correctly complement, the messenger RNA. To test this idea, growing cultures of Escherichia coli were treated with streptomycin to increase the frequency of errors during protein synthesis. Since the treated cells had a temperature-sensitive peptidyl-tRNA hydrolase and could not destroy dissociated peptidyl-tRNA, it was possible to measure the rate of its accumulation after raising the temperature to non-permissive conditions. Both low and high doses of streptomycin enhanced the rate of dissociation and accumulation of peptidyl-tRNA. The rank order of rates of dissociation/accumulation of various isoaccepting tRNA families was not significantly altered by the drug treatment. We concluded that streptomycin stimulated a normal pathway for dissociation of peptidyl-tRNA. Two streptomycin- resistant strains of E. coli had higher rates of dissociation of peptidyl-tRNA than did their sensitive parent strain. When treated with high doses of the drug, the resistant strains showed slightly reduced rates of dissociation of peptidyl-tRNA. These results were interpreted in terms of a two state, two site model for protein synthesis: streptomycin enhances the binding of aminoacyl-tRNA to a tight state of the ribosome A site; the strA mutation enhances translocation to a loose state of the ribosome P site.

  10. Induced mutations of rust resistance genes in wheat

    International Nuclear Information System (INIS)

    McIntosh, R.A.

    1983-01-01

    Induced mutations are being used as a tool to study genes for resistance in wheat. It was found that Pm1 can be separated from Lr20 and Sr15, but these two react like a single pleiotropic gene. Mutants were further examined in crosses and backmutations have been attempted. (author)

  11. Characterization of genomic sequence of a drought-resistant gene ...

    Indian Academy of Sciences (India)

    Characterization of genomic sequence of a drought-resistant gene. TaSnRK2.7 in wheat species. HONG YING ZHANG1,2, WEI LI3, XIN GUO MAO1 and RUI LIAN JING1∗. 1The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science,. Chinese Academy of Agricultural Sciences, ...

  12. Testing of disease-resistance of pokeweed antiviral protein gene ...

    African Journals Online (AJOL)

    Transformation of pokeweed antiviral protein gene (PAP) into plants was shown to improve plant resistance to several viruses or fungi pathogens with no much negative effect on plant growth. The non-virulent defective PAP inhibits only the virus but does not interfere with the host. A non-virulent defective PAP gene ...

  13. Isolation and characterization of a candidate gene for resistance to ...

    African Journals Online (AJOL)

    xudelin

    2012-05-17

    May 17, 2012 ... Cereal cyst nematode (CCN) (Heterodera avenae Woll.) is one of the most economically damaging endoparasite pests of wheat worldwide. We isolated and characterized a novel cereal CCN resistance candidate gene, CreV8, from Aegilops variabilis (2n = 28, UUSvSv). The gene was 3,568 bp long and.

  14. Occurrence, virulence genes and antibiotic resistance of enteropathogenic Escherichia coli (EPEC) from twelve bovine farms in the north-east of Ireland.

    Science.gov (United States)

    Bolton, D J; Ennis, C; McDowell, D

    2014-03-01

    Cattle faecal samples (n = 480) were collected from a cluster of 12 farms, and PCR screened for the presence of the intimin gene (eae). Positive samples were cultured, and colonies were examined for the presence of eae and verocytotoxin (vtx) genes. Colonies which were positive for the intimin gene and negative for the verocytotoxin genes were further screened using PCR for a range of virulence factors including bfpA, espA, espB, tir ehxA, toxB, etpD, katP, saa, iha, lpfAO157/OI-141 and lpfAO157/OI-154. Of the 480 faecal samples, 5.8% (28/480) were PCR positive, and one isolate was obtained from each. All 28 isolates obtained were bfpA negative and therefore atypical EPEC (aEPEC). The serotypes detected included O2:H27, O8:H36, O15:H2, O49:H+, O84:H28, O105:H7 and O132:H34 but half of the isolates could not be serogrouped using currently available antisera. Twenty-two (79%) of the isolates carried the tir gene but only 25% were espB positive, and all other virulence genes tested for were scarce or absent. Several isolates showed intermediate resistance to ciprofloxacin, kanamycin, nalidixic acid, minocycline and tetracycline; full resistance to nalidixic acid or tetracycline with one isolate (O-:H8) displaying resistance to aminoglycosides (kanamycin and streptomycin), quinolones (nalidixic acid) and sulphonamides. This study provides further evidence that cattle are a potential source of aEPEC and add to the very limited data currently available on virulence genes and antibiotic resistance in this pathogenic E. coli group in animals. © 2013 Blackwell Verlag GmbH.

  15. Emergence of Tetracycline Resistant Vibrio cholerae O1 Biotype El Tor Serotype Ogawa with Classical ctxB Gene from a Cholera Outbreak in Odisha, Eastern India

    Directory of Open Access Journals (Sweden)

    M. Jain

    2016-01-01

    Full Text Available In September 2010, a cholera outbreak was reported from Odisha, Eastern India. V. cholerae isolated from the clinical samples were biochemically and serologically confirmed as serogroup O1, biotype El Tor, and serotype Ogawa. Multiplex PCR screening revealed the presence of various genes, namely, ompW, ctxB, zot, rfbO1, tcp, ace, hlyA, ompU, rtx, and toxR, in all of the isolates. The isolates were resistant to co-trimoxazole, nalidixic acid, polymyxin B, spectinomycin, streptomycin, sulfamethoxazole, tetracycline, trimethoprim, and vibriostatic agent 2,4-diamino-6,7-diisopropylpteridine (O/129. Minimum inhibitory concentration of tetracycline decreased in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP, suggesting the involvement of efflux pumps. PCR analysis confirmed the presence of class I integrons as well as SXT elements harbouring antibiotic resistance genes in all isolates. Sequencing revealed the presence of ctxB gene of classical biotype in all the isolates. The isolates harboured an RS1-CTX prophage array with El Tor type rstR and classical ctxB on the large chromosome. The study indicated that the V. cholerae El Tor variants are evolving in the area with better antibiotic resistance and virulence potential.

  16. Environmental cycle of antibiotic resistance encoded genes: A systematic review

    Directory of Open Access Journals (Sweden)

    R. ghanbari

    2017-12-01

    Full Text Available Antibiotic-resistant bacteria and genes enter the environment in different ways. The release of these factors into the environment has increased concerns related to public health. The aim of the study was to evaluate the antibiotic resistance genes (ARGs in the environmental resources. In this systematic review, the data were extracted from valid sources of information including ScienceDirect, PubMed, Google Scholar and SID. Evaluation and selection of articles were conducted on the basis of the PRISMA checklist. A total of 39 articles were included in the study, which were chosen from a total of 1249 papers. The inclusion criterion was the identification of genes encoding antibiotic resistance against the eight important groups of antibiotics determined by using the PCR technique in the environmental sources including municipal and hospital wastewater treatment plants, animal and agricultural wastes, effluents from treatment plants, natural waters, sediments, and drinking waters. In this study, 113 genes encoding antibiotic resistance to eight groups of antibiotics (beta-lactams, aminoglycosides, tetracyclines, macrolides, sulfonamides, chloramphenicol, glycopeptides and quinolones were identified in various environments. Antibiotic resistance genes were found in all the investigated environments. The investigation of microorganisms carrying these genes shows that most of the bacteria especially gram-negative bacteria are effective in the acquisition and the dissemination of these pollutants in the environment. Discharging the raw wastewaters and effluents from wastewater treatments acts as major routes in the dissemination of ARGs into environment sources and can pose hazards to public health.

  17. The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

    Science.gov (United States)

    Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

    2017-07-01

    The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  18. Interspecies gene transfer provides soybean resistance to a fungal pathogen.

    Science.gov (United States)

    Langenbach, Caspar; Schultheiss, Holger; Rosendahl, Martin; Tresch, Nadine; Conrath, Uwe; Goellner, Katharina

    2016-02-01

    Fungal pathogens pose a major challenge to global crop production. Crop varieties that resist disease present the best defence and offer an alternative to chemical fungicides. Exploiting durable nonhost resistance (NHR) for crop protection often requires identification and transfer of NHR-linked genes to the target crop. Here, we identify genes associated with NHR of Arabidopsis thaliana to Phakopsora pachyrhizi, the causative agent of the devastating fungal disease called Asian soybean rust. We transfer selected Arabidopsis NHR-linked genes to the soybean host and discover enhanced resistance to rust disease in some transgenic soybean lines in the greenhouse. Interspecies NHR gene transfer thus presents a promising strategy for genetically engineered control of crop diseases. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  19. 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

  20. 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

  1. 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 bla TEM , bla SHV , 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.

  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. Mechanisms of Bactericide Resistance in Phytopathogenic Bacteria(Abstracts of the Research by the Winners of the Young Scientist Award)

    OpenAIRE

    Masami, NAKAJIMA; School of Agriculture, Ibaraki University

    2002-01-01

    Bactericides containing copper and streptomycin have been widely used to control bacterial plant diseases. However, the efficacy of copper and streptomycin have been reduced by the development of copper- and streptomycin-resistant bacterial strains. Understanding the mechanism of resistance is necessary for the prevention and management of resistance. In this study, the mechanisms of copper and streptomycin resistance in Pseudomonas syringae pv. actinidiae were analyzed.

  4. Genes involved in barley yellow dwarf virus resistance of maize.

    Science.gov (United States)

    Horn, Frederike; Habekuß, Antje; Stich, Benjamin

    2014-12-01

    The results of our study suggest that genes involved in general resistance mechanisms of plants contribute to variation of BYDV resistance in maize. With increasing winter temperatures in Europe, Barley yellow dwarf virus (BYDV) is expected to become a prominent problem in maize cultivation. Breeding for resistance is the best strategy to control the disease and break the transmission cycle of the virus. The objectives of our study were (1) to determine genetic variation with respect to BYDV resistance in a broad germplasm set and (2) to identify single nucleotide polymorphism (SNP) markers linked to genes that are involved in BYDV resistance. An association mapping population with 267 genotypes representing the world's maize gene pool was grown in the greenhouse. Plants were inoculated with BYDV-PAV using viruliferous Rhopalosiphum padi. In the association mapping population, we observed considerable genotypic variance for the trait virus extinction as measured by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and the infection rate. In a genome-wide association study, we observed three SNPs significantly [false discovery rate (FDR) = 0.05] associated with the virus extinction on chromosome 10 explaining together 25 % of the phenotypic variance and five SNPs for the infection rate on chromosomes 4 and 10 explaining together 33 % of the phenotypic variance. The SNPs significantly associated with BYDV resistance can be used in marker assisted selection and will accelerate the breeding process for the development of BYDV resistant maize genotypes. Furthermore, these SNPs were located within genes which were in other organisms described to play a role in general resistance mechanisms. This suggests that these genes contribute to variation of BYDV resistance in maize.

  5. 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.

  6. The relationship between codon usage bias and cold resistant genes

    International Nuclear Information System (INIS)

    Barozai, M.Y.; Din, M.

    2014-01-01

    This research is based on synonymous codon usage which has been well-known as a feature that affects typical expression level of protein in an organism. Different organisms prefer different codons for same amino acid and this is called Codon Usage Bias (CUB). The codon usage directly affects the level or even direction of changes in protein expression in responses to environmental stimuli. Cold stress is a major abiotic factor that limits the agricultural productivity of plants. In the recent study CUB has been studied in Arabidopsis thaliana cold resistant and housekeeping genes and their homologs in rice (Oryza sativa) to understand the cold stress and housekeeping genes relation with CUB. Six cold resistant and three housekeeping genes in Arabidopsis thaliana and their homologs in rice, were subjected to CUB analysis. The three cold resistant genes (DREB1B, RCI and MYB15) showed more than 50% (52%, 61% and 66% respectively) similar codon usage bias for Arabidopsis thaliana and rice. On the other hand three cold resistant genes (MPK3, ICE1 and ZAT12) showed less than 50% (38%, 38% and 47% respectively) similar codon usage bias for Arabidopsis thaliana and rice. The three housekeeping genes (Actin, Tubulin and Ubiquitin) showed 76% similar codon usage bias for Arabidopsis thaliana and rice. This study will help to manage the plant gene expression through codon optimization under the cold stress. (author)

  7. Evaluation on the Use of β-Lactamase and Aminoglycoside Modifying Enzyme Gene Sequences as Markers for the Early Detection of Antibiotic Resistance Profile of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Victor A. Doss

    2004-01-01

    Full Text Available Pseudomonas aeruginosa is one of the major causes of infections including the hospital acquired (Nosocomial infections. Detection of them and their antibiotic resistance profile by conventional method takes about three days. Recently, DNA based diagnostic methods are being used for the identification of the pathogens. Hence we have tested a rapid and sensitive method using DNA sequences as markers for detecting the presence of three genes coding for the enzymes that inactivate the two most commonly used Anti-pseudomonadal drugs such as β-lactam antibiotics (Penicillin, and its derivatives and Aminoglycosides such as Gentamicin, Tobramycin, Amikacin, Streptomycin. The internal region of these genes were used for designing and synthesizing primers and these primers were used in Polymerase Chain Reaction (PCR to screen for the presence of these genes in the clinical isolates and to label them non-radioactively with Biotin. They in turn were used to detect the presence of the antibiotic resistance genes in the clinical isolates by hybridization. The specificity (ratio of positive results obtained in both methods and the sensitivity (the minimum amount of sample DNA and the labeled probe required for the tests were evaluated.

  8. Glucose concentration and streptomycin alter in vitro muscle function and metabolism.

    Science.gov (United States)

    Khodabukus, Alastair; Baar, Keith

    2015-06-01

    Cell culture conditions can vary between laboratories and have been optimised for 2D cell culture. In this study, engineered muscle was cultured in 5.5 mM low glucose (LG) or 25 mM high glucose (HG) and in the absence or presence (+S) of streptomycin and the effect on C2C12 tissue-engineered muscle function and metabolism was determined. Following 2 weeks differentiation, streptomycin (3-fold) and LG (0.5-fold) significantly decreased force generation. LG and/or streptomycin resulted in upward and leftward shifts in the force-frequency curve and slowed time-to-peak tension and half-relaxation time. Despite changes in contractile dynamics, no change in myosin isoform was detected. Instead, changes in troponin isoform, calcium sequestering proteins (CSQ and parvalbumin) and the calcium uptake protein SERCA predicted the changes in contractile dynamics. Culturing in LG and/or streptomycin resulted in increased fatigue resistance despite no change in the mitochondrial enzymes SDH, ATPsynthase and cytochrome C. However, LG resulted in increases in the β-oxidation enzymes LCAD and VLCAD and the fatty acid transporter CPT-1, indicative of a greater capacity for fat oxidation. In contrast, HG resulted in increased GLUT4 content and the glycolytic enzyme PFK, indicative of a more glycolytic phenotype. These data suggest that streptomycin has negative effects on force generation and that glucose can be used to shift engineered muscle phenotype via changes in calcium-handling and metabolic proteins. © 2014 Wiley Periodicals, Inc.

  9. Trends in antimicrobial susceptibility in relation to antimicrobial usage and presence of resistance genes in Staphylococcus hyicus isolated from exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Jensen, Lars Bogø

    2002-01-01

    From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin...... (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....... Resistance to sulphametazole increased from 17% in 1996 to 30% in 1998 but has since decreased to 4% in 2001. Resistance to trimethoprim increased to 51% in 1997 and decreased to 21% in 2001. Resistance to tetracycline (21-31%) remained relatively constant during 1996-2000, but increased to 47% in 2001...

  10. Using long-term experimental evolution to uncover the patterns and determinants of molecular evolution of an Escherichia coli natural isolate in the streptomycin treated mouse gut

    Science.gov (United States)

    Ghalayini, Mohamed; Magnan, Mélanie; Glodt, Jérémy; Pintard, Coralie; Dion, Sara; Denamur, Erick; Tenaillon, Olivier

    2017-01-01

    Though microbial ecology of the gut is now a major focus of interest, little is known about the molecular determinants of microbial adaptation in the gut. Experimental evolution coupled with whole genome sequencing can provide insights of the adaptive process. In vitro experiments have revealed some conserved patterns: intermediate convergence, epistatic interactions between beneficial mutations and mutations in global regulators. To test the relevance of these patterns and to identify the selective pressures acting in vivo, we have performed a long-term adaptation of an E. coli natural isolate, the streptomycin resistant strain 536, in the digestive tract of streptomycin treated mice. After a year of evolution, a clone from 15 replicates was sequenced. Consistently with in vitro observations, the identified mutations revealed a strong pattern of convergence at the mutation, gene, operon and functional levels. Yet, the rate of molecular evolution was lower than in in vitro and no mutations in global regulators were recovered. More specific targets were observed: the dgo operon, involved in the galactonate pathway that improved growth on D-galactonate, and rluD and gidB, implicated in the maturation of the ribosomes, which mutations improved growth only in the presence of streptomycin. As in vitro, the non-random associations of mutations within the same pathways suggested a role of epistasis in shaping the adaptive landscape. Overall, we show that “evolve and sequence” approach coupled to an analysis of convergence, when applied to a natural isolate, can be used to study adaptation in vivo and uncover the specific selective pressures of that environment. PMID:27661780

  11. Using long-term experimental evolution to uncover the patterns and determinants of molecular evolution of an Escherichia coli natural isolate in the streptomycin-treated mouse gut.

    Science.gov (United States)

    Lescat, Mathilde; Launay, Adrien; Ghalayini, Mohamed; Magnan, Mélanie; Glodt, Jérémy; Pintard, Coralie; Dion, Sara; Denamur, Erick; Tenaillon, Olivier

    2017-04-01

    Although microbial ecology of the gut is now a major focus of interest, little is known about the molecular determinants of microbial adaptation in the gut. Experimental evolution coupled with whole-genome sequencing can provide insights of the adaptive process. In vitro experiments have revealed some conserved patterns: intermediate convergence, and epistatic interactions between beneficial mutations and mutations in global regulators. To test the relevance of these patterns and to identify the selective pressures acting in vivo, we have performed a long-term adaptation of an E. coli natural isolate, the streptomycin-resistant strain 536, in the digestive tract of streptomycin-treated mice. After a year of evolution, a clone from 15 replicates was sequenced. Consistently with in vitro observations, the identified mutations revealed a strong pattern of convergence at the mutation, gene, operon and functional levels. Yet, the rate of molecular evolution was lower than in in vitro, and no mutations in global regulators were recovered. More specific targets were observed: the dgo operon, involved in the galactonate pathway that improved growth on D-galactonate, and rluD and gidB, implicated in the maturation of the ribosomes, which mutations improved growth only in the presence of streptomycin. As in vitro, the nonrandom associations of mutations within the same pathways suggested a role of epistasis in shaping the adaptive landscape. Overall, we show that 'evolve and sequence' approach coupled with an analysis of convergence, when applied to a natural isolate, can be used to study adaptation in vivo and uncover the specific selective pressures of that environment. © 2016 John Wiley & Sons Ltd.

  12. 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.

  13. 40 CFR 180.245 - Streptomycin; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Streptomycin; tolerances for residues...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.245 Streptomycin; tolerances for residues. (a) General. (1) Tolerances are established for...

  14. 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.

  15. The rpg4/Rpg5 stem rust resistance locus in barley: resistance genes and cytoskeleton dynamics.

    Science.gov (United States)

    Brueggeman, Robert; Steffenson, Brian J; Kleinhofs, Andris

    2009-04-01

    Two closely linked resistance genes, rpg4 and Rpg5, conferring resistance to several races of Puccinia graminis, were cloned and characterized. The Rpg5 gene confers resistance to an isolate of Puccinia graminis f. sp. secalis (Pgs), while rpg4 confers resistance to Puccinia graminis f. sp. tritici (Pgt). Rpg5 is a novel gene containing nucleotide binding site-leucine rich repeat domains in combination with a serine threonine protein kinase domain. High-resolution mapping plus allele and recombinant sequencing identified the rpg4 gene, which encodes an actin depolymerizing factor-like protein (ADF2). Resistance against the Pgt races QCCJ, MCCF, TTKSK (aka Ug99) and RCRS requires both Rpg5 and rpg4, while Rpg5 alone confers resistance to Pgs isolate 92-MN-90. The dependency on the actin modifying protein ADF2 indicates cytoskeleton reorganization or redirection plays a role in pathogen-host interactions. Rpg5 may interact with ADF2 to activate or deactivate its function in the resistance response. Alternatively, Rpg5 could initiate signal transduction leading to resistance in response to detecting ADF2 protein modification. Pgt may redirect the actin cytoskeleton by inducing modifications of ADF2. The redirection of actin could possibly enable the pathogen to develop a haustoria-plant cell cytoskeleton interface for acquisition of nutrients.

  16. A novel gene of Kalanchoe daigremontiana confers plant drought resistance.

    Science.gov (United States)

    Wang, Li; Zhu, Chen; Jin, Lin; Xiao, Aihua; Duan, Jie; Ma, Luyi

    2018-02-07

    Kalanchoe (K.) daigremontiana is important for studying asexual reproduction under different environmental conditions. Here, we describe a novel KdNOVEL41 (KdN41) gene that may confer drought resistance and could thereby affect K. daigremontiana development. The detected subcellular localization of a KdN41/Yellow Fluorescent Protein (YFP) fusion protein was in the nucleus and cell membrane. Drought, salt, and heat stress treatment in tobacco plants containing the KdN41 gene promoter driving β-glucuronidase (GUS) gene transcription revealed that only drought stress triggered strong GUS staining in the vascular tissues. Overexpression (OE) of the KdN41 gene conferred improved drought resistance in tobacco plants compared to wild-type and transformed with empty vector plants by inducing higher antioxidant enzyme activities, decreasing cell membrane damage, increasing abscisic acid (ABA) content, causing reinforced drought resistance related gene expression profiles. The 3,3'-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) staining results also showed less relative oxygen species (ROS) content in KdN41-overexpressing tobacco leaf during drought stress. Surprisingly, by re-watering after drought stress, KdN41-overexpressing tobacco showed earlier flowering. Overall, the KdN41 gene plays roles in ROS scavenging and osmotic damage reduction to improve tobacco drought resistance, which may increase our understanding of the molecular network involved in developmental manipulation under drought stress in K. daigremontiana.

  17. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

    OpenAIRE

    Adelowo, Olawale O.; Fagade, Obasola E.; Agersø, Yvonne

    2014-01-01

    Introduction: This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Methodology: Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. Results: A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resista...

  18. Effect of swine manure application timing on the persistence and transport of antibiotic-resistant Enterococcus and resistance genes

    Science.gov (United States)

    Swine manure applied to agricultural fields may lead to the transport of antibiotic resistant bacteria and antibiotic resistance genes to freshwater systems. Enterococci were studied because they are fecal indicator bacteria associated with manure. Resistance genes include genes from live cells, dea...

  19. Vancomycin-resistance phenotypes, vancomycin-resistance genes, and resistance to antibiotics of enterococci isolated from food of animal origin.

    Science.gov (United States)

    Gousia, Panagiota; Economou, Vangelis; Bozidis, Petros; Papadopoulou, Chrissanthy

    2015-03-01

    In the present study, 500 raw beef, pork, and chicken meat samples and 100 pooled egg samples were analyzed for the presence of vancomycin-resistant enterococci, vancomycin-resistance phenotypes, and resistance genes. Of 141 isolates of enterococci, 88 strains of Enterococcus faecium and 53 strains of E. faecalis were identified. The most prevalent species was E. faecium. Resistance to ampicillin (n = 93, 66%), ciprofloxacin (n = 74, 52.5%), erythromycin (n = 73, 51.8%), penicillin (n = 59, 41.8%) and tetracycline (n = 52, 36.9%) was observed, while 53.2% (n = 75) of the isolates were multiresistant and 15.6% (n = 22) were susceptible to all antibiotics. Resistance to vancomycin was exhibited in 34.1% (n = 30) of the E. faecium isolates (n = 88) and 1.9% (n = 1) of the E. faecalis isolates (n = 53) using the disc-diffusion test and the E-test. All isolates were tested for vanA and vanB using real-time polymerase chain reaction (PCR) and multiplex PCR, and for vanC, vanD, vanE, vanG genes using multiplex PCR only. Among E. faecalis isolates, no resistance genes were identified. Among the E. faecium isolates, 28 carried the vanA gene when tested by multiplex PCR and 29 when tested with real-time PCR. No isolate carrying the vanC, vanD, vanE, or vanG genes was identified. Melting-curve analysis of the positive real-time PCR E. faecium isolates showed that 22 isolates carried the vanA gene only, 2 isolates the vanB2,3 genes only, and seven isolates carried both the vanA and vanB2,3 genes. Enterococci should be considered a significant zoonotic pathogen and a possible reservoir of genes encoding resistance potentially transferred to other bacterial species.

  20. Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam

    Science.gov (United States)

    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

    2017-01-01

    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 blaTEM gene being more common than blaCTX-M. Co-harbouring of the blaCTX-M, blaTEM 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. PMID:28661465

  1. 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.

  2. The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence

    OpenAIRE

    Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G.; Singh, Davinder; Park, Robert F.; Lagudah, Evans; Ayliffe, Michael

    2017-01-01

    Summary The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad?spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field?grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when ...

  3. Detection of Enterohemorrhagic Escherichia coli Related Genes in E. coli Strains Belonging to B2 Phylogroup Isolated from Urinary Tract Infections in Combination with Antimicrobial Resistance Phenotypes

    Directory of Open Access Journals (Sweden)

    Hamid Staji

    2017-07-01

    Full Text Available Background:  This study was conducted to detect the prevalence of EHEC virulence genes and antimicrobial resistance profile of Escherichia coli strains belonging to B2 phylogroup implicated in Urinary tract infections in Semnan, Iran.Methods:   From 240 urine samples 160 E. coli strains were isolated, biochemically. Then, E. coli isolates were examined by Multiplex-PCR for phylogenetic typing and detection of virulence genes (hly, stx1, stx2, eae associated with Enterohemorrhagic E. coli. Finally, Antimicrobial resistance of E. coli isolates were characterized using Disk Diffusion method.  Results:  From 160 E. coli isolates, 75 strains (47% were assigned to B2 phylogenetic group and prevalence of virulence genes were as follow: hly (21.3%, stx1 (16%, stx2 (10.6% and eae (6.7%, subsequently.  Phenotypic antimicrobial resistance of B2 isolates showed that all isolates were sensitive to Meropenem and Furazolidone and then highest frequency of resistance was observed to Streptomycin, Oxytetracycline, Neomycin, Nalidixic acid and Ampicillin (98.7% to 49.3%. Also low resistance prevalence was observed in case of Ceftizoxime, Lincospectin, Imipenem, Chloramphenicol and flurefenicole (16% to 1.3%.Conclusion:   The data suggest a high prevalence of antibiotic resistance in UPEC strains belonging to B2 phylogroup even for the antimicrobials using in pet and farm animals and their potential to cause EHEC specific clinical symptoms which may represent a serious health risk since these strains can be transmitted to GI tract and act as a reservoir for other uropathogenic E. coli and commensal strains.

  4. 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 ...

  5. Streptomycin decreases the functional shift to a slow phenotype induced by electrical stimulation in engineered muscle.

    Science.gov (United States)

    Khodabukus, Alastair; Baar, Keith

    2015-03-01

    Chronic low-frequency stimulation (CLFS) has long been used to induce a fast-to-slow phenotype shift in skeletal muscle. In this study, we explore the role of frequency (10 and 20 Hz), active time (15-60%), and streptomycin in inducing a fast-to-slow shift in engineered muscle. We found that C2C12 engineered muscle could respond to CLFS with an adult-like active time of 60% and found that a constant 10 Hz train of 0.6 s, followed by 0.4 s rest, induced a partial fast-to-slow phenotype shift. Following 2 weeks of CLFS, time-to-peak tension (TPT) (control [CTL]=40.9±0.2 ms; 10 Hz=58.5±3.5 ms; 20 Hz=48.2±2.7 ms) and half-relaxation time (1/2RT) (CTL=50.4±0.6 ms; 10 Hz=76.1±3.3 ms; 20 Hz=66.6±2.3 ms) slowed significantly in frequency, but not in an active time-dependent manner. Streptomycin significantly blunted the slowing of TPT and 1/2RT induced by CLFS by minimizing the fast-to-slow shift in SERCA isoform. Streptomycin (Nonstim=-42.8%±2.5%; Stim=-38.1%±3.6%) significantly prevented the improvement in fatigue resistance seen in CTL constructs (Nonstim=-58.4%±3.6%; Stim=-27.8%±1.7%). Streptomycin reduced the increase seen in GLUT4 protein following CLFS (CTL=89.4%±6.7%; STREP=41.0%±4.3%) and prevented increases in the mitochondrial proteins succinate dehydrogenase (SDH) and ATP synthase. These data demonstrate that streptomycin significantly blunts the fast-to-slow shift induced by CLFS. In the absence of streptomycin, CLFS induced slowing of contractile dynamics and improved fatigue resistance and suggests that this model can be used to study the mechanisms underlying CLFS-induced adaptations in muscle phenotype.

  6. Comparative genome analysis and resistance gene mapping in grain legumes

    International Nuclear Information System (INIS)

    Young, N.D.

    1998-01-01

    Using, DNA markers and genome organization, several important disease resistance genes have been analyzed in mungbean (Vigna radiata), cowpea (Vigna unguiculata), common bean (Phaseolus vulgaris), and soybean (Glycine max). In the process, medium-density linkage maps consisting of restriction fragment length polymorphism (RFLP) markers were constructed for both mungbean and cowpea. Comparisons between these maps, as well as the maps of soybean and common bean, indicate that there is significant conservation of DNA marker order, though the conserved blocks in soybean are much shorter than in the others. DNA mapping results also indicate that a gene for seed weight may be conserved between mungbean and cowpea. Using the linkage maps, genes that control bruchid (genus Callosobruchus) and powdery mildew (Erysiphe polygoni) resistance in mungbean, aphid resistance in cowpea (Aphis craccivora), and cyst nematode (Heterodera glycines) resistance in soybean have all been mapped and characterized. For some of these traits resistance was found to be oligogenic and DNA mapping uncovered multiple genes involved in the phenotype. (author)

  7. 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

    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......, 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...... results support the existence of ancient and, possibly, recent transfers of ARGs from antibiotic-producing actinobacteria to proteobacteria, and provide evidence for a defined mechanism....

  8. Computational identification of potent inhibitors for Streptomycin 3″-adenylyltransferase of Serratia marcescens.

    Science.gov (United States)

    Prabhu, Dhamodharan; Vidhyavathi, Ramasamy; Jeyakanthan, Jeyaraman

    2017-02-01

    Serratia marcescens is an opportunistic pathogen responsible for the respiratory and urinary tract infections in humans. The antibiotic resistance mechanism of S. marcescens is mediated through aminoglycoside modification enzyme that transfer adenyl group from substrate to antibiotic through regiospecific transfers for the inactivation of antibiotics. Streptomycin 3 ″ -adenylyltransferase acts on the 3' position of the antibiotic and considered as a novel drug target to overcome bacterial antibiotic resistance. Till now, there is no experimentally solved crystal structure of Streptomycin 3″-adenylyltransferase in S. marcescens. Hence, the present study was initiated to construct the three dimensional structure of Streptomycin 3″-adenylyltransferase in order to understand the binding mechanism. The modeled structure was subjected to structure-based virtual screening to identify potent compounds from the five chemical structure databases. Furthermore, different computational methods such as molecular docking, molecular dynamics simulations, ADME toxicity assessment, free energy and density functional theory calculations predicted the structural, binding and pharmacokinetic properties of the best five compounds. Overall, the results suggested that stable binding confirmation of the five potent compounds were mediated through hydrophobic, π-π stacking, salt bridges and hydrogen bond interactions. The identified compounds could pave way for the development of anti-pathogenic agents as potential drug entities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. High chlorpyrifos resistance in Culex pipiens mosquitoes: strong synergy between resistance genes.

    Science.gov (United States)

    Alout, H; Labbé, P; Berthomieu, A; Makoundou, P; Fort, P; Pasteur, N; Weill, M

    2016-02-01

    We investigated the genetic determinism of high chlorpyrifos resistance (HCR), a phenotype first described in 1999 in Culex pipiens mosquitoes surviving chlorpyrifos doses ⩾1 mg l(-1) and more recently found in field samples from Tunisia, Israel or Indian Ocean islands. Through chlorpyrifos selection, we selected several HCR strains that displayed over 10 000-fold resistance. All strains were homozygous for resistant alleles at two main loci: the ace-1 gene, with the resistant ace-1(R) allele expressing the insensitive G119S acetylcholinesterase, and a resistant allele of an unknown gene (named T) linked to the sex and ace-2 genes. We constructed a strain carrying only the T-resistant allele and studied its resistance characteristics. By crossing this strain with strains harboring different alleles at the ace-1 locus, we showed that the resistant ace-1(R) and the T alleles act in strong synergy, as they elicited a resistance 100 times higher than expected from a simple multiplicative effect. This effect was specific to chlorpyrifos and parathion and was not affected by synergists. We also examined how HCR was expressed in strains carrying other ace-1-resistant alleles, such as ace-1(V) or the duplicated ace-1(D) allele, currently spreading worldwide. We identified two major parameters that influenced the level of resistance: the number and the nature of the ace-1-resistant alleles and the number of T alleles. Our data fit a model that predicts that the T allele acts by decreasing chlorpyrifos concentration in the compartment targeted in insects.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Martina eKyselkova

    2015-05-01

    Full Text Available 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 smaller farms remains to be evaluated. Here we monitor the spread of tetracycline resistance (TC-r genes at a middle-size conventional dairy farm, where chlortetracycline (CTC, as intrauterine suppository is prophylactically used after each calving. Our study has shown that animals at the farm acquired the TC-r genes in their early age (1-2 weeks, likely due to colonization with TC-resistant bacteria from their mothers and/or the farm environment. The relative abundance of the TC-r genes tet(W, tet(Q and tet(M in fresh excrements of calves was about 1-2 orders of magnitude higher compared to heifers and dairy cows, possibly due to the presence of antibiotic residues in milk fed to calves. The occurrence and abundance of TC-r genes in fresh excrements of heifers and adult cows remained unaffected by intrauterine CTC applications, with tet(O, tet(Q and tet(W representing a ‘core TC-resistome’ of the farm, and tet(A, tet(M, tet(Y and tet(X occurring occasionally. The genes tet(A, tet(M, tet(Y and tet(X were shown to be respectively harbored by Shigella, Lactobacillus and Clostridium, Acinetobacter, and Wautersiella. Soil in the farm proximity, as well as field soil to which manure from the farm was applied, was contaminated with TC-r genes occurring in the farm, and some of the TC-r genes persisted in the field over 3 months following the manure application. Concluding, our study shows that antibiotic resistance genes may be a stable part of the intestinal metagenome of cattle even if antibiotics are not used for growth stimulation, and that smaller dairy farms may also contribute to environmental pollution with antibiotic resistance genes.

  12. Mutations in 23 S ribosomal RNA perturb transfer RNA selection and can lead to streptomycin dependence.

    Science.gov (United States)

    Bilgin, N; Ehrenberg, M

    1994-01-21

    Escherichia coli ribosomes with a G to C transversion at position 2661 in 23 S ribosomal RNA are more accurate in tRNA selection than wild-type ribosomes. This enhanced accuracy is due to improved initial selection of ternary complexes rather than proofreading of aminoacyl tRNAs. The 2661C mutation reduces the binding rate of cognate ternary complexes to the A-site. This binding rate deficiency becomes dramatic when ribosomes also harbour an S12 mutation with a streptomycin-resistant, hyperaccurate phenotype. In this case, severe loss of kinetic efficiency in EF-Tu function leads to cell death. Streptomycin restores viability by increasing the association rate of ternary complex to these doubly altered ribosomes. The binding rate of EF-G to 2661C ribosomes is also reduced while the translocation rate is unaffected.

  13. Dissemination of metal resistance genes among animal methicillin-resistant coagulase-negative Staphylococci.

    Science.gov (United States)

    Argudín, M Angeles; Butaye, Patrick

    2016-04-01

    The use of metals as feed supplement has been recognized as a potential driver for co-selection of methicillin-resistant Staphylococcus aureus in pigs. However, the prevalence of these determinants in methicillin-resistant coagulase-negative staphylococci (MRCoNS) is largely unknown. In this study, a collection of 130 MRCoNS from pigs and veal calves were investigated for the presence of metal-resistance genes (czrC, copB, cadD, arsA) associated to SCCmec. Near half of the isolates carried metal resistance genes (czrC 5.4%, copB 38.5%, cadD 7.7%, arsA 26.2%) regardless of their SCCmec type. The increased use of metals in livestock animals, especially zinc in pigs in several European countries may co-select for methicillin-resistance in several staphylococcal species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Tagging of resistance gene(s) to rhizomania disease in sugar beet ...

    African Journals Online (AJOL)

    SERVER

    2008-02-19

    Feb 19, 2008 ... plasmodiophoride-like fungus, Polymyxa betae Keskin. (1964) (Tamada and Richard, 1992). Source of resistance to rhizomania were found in Holly sugar beet company source (Lewellen, 1987). Resistance in Holly is simply inherited by a single dominant gene(Rz1). (Lewellen et al., 1987; Scholten et al., ...

  15. 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 ...

  16. Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in 'Thatcher' Wheat.

    Directory of Open Access Journals (Sweden)

    Colin W Hiebert

    Full Text Available Stem rust, caused by Puccinia graminis (Pgt, is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. 'Thatcher' wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in 'Thatcher' and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for 'Thatcher'-derived APR in several environments and this resistance was enhanced in the presence of Lr34.

  17. Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in 'Thatcher' Wheat.

    Science.gov (United States)

    Hiebert, Colin W; Kolmer, James A; McCartney, Curt A; Briggs, Jordan; Fetch, Tom; Bariana, Harbans; Choulet, Frederic; Rouse, Matthew N; Spielmeyer, Wolfgang

    2016-01-01

    Stem rust, caused by Puccinia graminis (Pgt), is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. 'Thatcher' wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in 'Thatcher' and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for 'Thatcher'-derived APR in several environments and this resistance was enhanced in the presence of Lr34.

  18. Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in ‘Thatcher’ Wheat

    Science.gov (United States)

    Hiebert, Colin W.; Kolmer, James A.; McCartney, Curt A.; Briggs, Jordan; Fetch, Tom; Bariana, Harbans; Choulet, Frederic; Rouse, Matthew N.; Spielmeyer, Wolfgang

    2016-01-01

    Stem rust, caused by Puccinia graminis (Pgt), is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. ‘Thatcher’ wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in ‘Thatcher’ and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for ‘Thatcher’-derived APR in several environments and this resistance was enhanced in the presence of Lr34. PMID:27309724

  19. Synthesis, characterization, controlled release, and antibacterial studies of a novel streptomycin chitosan magnetic nanoantibiotic

    Directory of Open Access Journals (Sweden)

    Hussein-Al-Ali SH

    2014-01-01

    Full Text Available Samer Hasan Hussein-Al-Ali,1 Mohamed Ezzat El Zowalaty,2,6 Mohd Zobir Hussein,3 Maznah Ismail,1,4 Thomas J Webster,5,7 1Laboratory of Molecular Biomedicine, 2Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, 3Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology, 4Department of Nutrition and Dietetics, Faculty of Medicine and Health Science, Universiti Putra Malaysia, Selangor, Malaysia; 5Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USA; 6Department of Environmental Health, Faculty of Public Health and Tropical Medicine, Jazan University, Jazan, 7Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: This study describes the preparation, characterization, and controlled release of a streptomycin-chitosan-magnetic nanoparticle-based antibiotic in an effort to improve the treatment of bacterial infections. Specifically, chitosan-magnetic nanoparticles were synthesized by an incorporation method and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometry. Streptomycin was incorporated into the nanoparticles to form a streptomycin-coated chitosan-magnetic nanoparticle (Strep-CS-MNP nanocomposite. The release profiles showed an initially fast release, which became slower as time progressed. The percentage of drug released after 350 minutes was around 100%, and the best fit mathematical model for drug release was the pseudo-second order model. The Strep-CS-MNP nanocomposite showed enhanced antibacterial activity against methicillin-resistant Staphylococcus aureus. This study forms a significant basis for further investigation of the Strep-CS-MNP nanocomposite in the treatment of various bacterial infections. Keywords: magnetic nanoparticles, streptomycin, nanoantibiotics, chitosan, release

  20. Association mapping and gene-gene interaction for stem rust resistance in CIMMYT spring wheat germplasm.

    Science.gov (United States)

    Yu, Long-Xi; Lorenz, Aaron; Rutkoski, Jessica; Singh, Ravi P; Bhavani, Sridhar; Huerta-Espino, Julio; Sorrells, Mark E

    2011-12-01

    The recent emergence of wheat stem rust Ug99 and evolution of new races within the lineage threatens global wheat production because they overcome widely deployed stem rust resistance (Sr) genes that had been effective for many years. To identify loci conferring adult plant resistance to races of Ug99 in wheat, we employed an association mapping approach for 276 current spring wheat breeding lines from the International Maize and Wheat Improvement Center (CIMMYT). Breeding lines were genotyped with Diversity Array Technology (DArT) and microsatellite markers. Phenotypic data was collected on these lines for stem rust race Ug99 resistance at the adult plant stage in the stem rust resistance screening nursery in Njoro, Kenya in seasons 2008, 2009 and 2010. Fifteen marker loci were found to be significantly associated with stem rust resistance. Several markers appeared to be linked to known Sr genes, while other significant markers were located in chromosome regions where no Sr genes have been previously reported. Most of these new loci colocalized with QTLs identified recently in different biparental populations. Using the same data and Q + K covariate matrices, we investigated the interactions among marker loci using linear regression models to calculate P values for pairwise marker interactions. Resistance marker loci including the Sr2 locus on 3BS and the wPt1859 locus on 7DL had significant interaction effects with other loci in the same chromosome arm and with markers on chromosome 6B. Other resistance marker loci had significant pairwise interactions with markers on different chromosomes. Based on these results, we propose that a complex network of gene-gene interactions is, in part, responsible for resistance to Ug99. Further investigation may provide insight for understanding mechanisms that contribute to this resistance gene network.

  1. Thioridazine affects transcription of genes involved in cell wall biosynthesis in methicillin-resistant Staphylococcus aureus

    DEFF Research Database (Denmark)

    Bonde, Mette; Højland, Dorte Heidi; Kolmos, Hans Jørn

    2011-01-01

    have previously shown that the expression of some resistance genes is abolished after treatment with thioridazine and oxacillin. To further understand the mechanism underlying the reversal of resistance, we tested the expression of genes involved in antibiotic resistance and cell wall biosynthesis...... reversal of resistance by thioridazine relies on decreased expression of specific genes involved in cell wall biosynthesis....

  2. Isolation of NBS-LRR class resistant gene (I2 gene) from tomato ...

    African Journals Online (AJOL)

    aghomotsegin

    2013-10-16

    Oct 16, 2013 ... Isolation of NBS-LRR class resistant gene (I2 gene) from tomato cultivar Heamsona ... avirulence protein or effector protein secreted by fungal pathogen during the host colonization in tomato. These effector proteins .... and efficient method for isolation of genomic DNA from plant tissue. J. Cell Tissue Res.

  3. 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.

  4. 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 ...

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

    African Journals Online (AJOL)

    Reports on the emergence of insect resistance to Bacillus thuringiensis delta endotoxins have raised doubts on the sustainability of Bt-toxin based pest management technologies. Corporate industry has responded to this challenge with innovations that include gene pyramiding among others. Pyramiding entails stacking ...

  6. Determination and expression of genes for resistance to blast ...

    African Journals Online (AJOL)

    Determination and expression of genes for resistance to blast (Magnaporthe oryza) in Basmati and non-Basmati indica rices (Oryza sativa L.) Naveen Kumar, D Singh, S Gupta, A Sirohi, B Ramesh, Preeti Sirohi, Parul Sirohi, Atar Singh, N Kumar, A Kumar, Rajendra Kumar, R Kumar, J Singh, P. Kumar, P. Chauhan, ...

  7. Gene interactions and genetics of blast resistance and yield ...

    Indian Academy of Sciences (India)

    2014-08-11

    Aug 11, 2014 ... Keywords. blast; gene action; generation mean analysis; resistance; yield. Journal of Genetics, Vol. 93, No. .... Utilizing the variance of different generations, the variances of A, B, C and D scales were ...... Jia Y. 2003 Marker assisted selection for the control of rice blast disease. Pesticide Outlook 14 ...

  8. Evaluating antibiotic resistance genes in soils with applied manures

    Science.gov (United States)

    Antibiotics are commonly used in livestock production to promote growth and combat disease. Recent studies have shown the potential for spread of antibiotic resistance genes (ARG) to the environment following application of livestock manures. In this study, concentrations of bacteria with ARG in soi...

  9. 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 ...

  10. 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 ...

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

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2017-01-04

    Jan 4, 2017 ... 2. State Key Laboratory of Biology for Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of. Agricultural Sciences, Beijing 100193, China. Received 10 October, 2016; Accepted 14 December, 2016. A study was conducted to detect the presence of disease resistance genes to ...

  12. Cloning of a carbendazim-resistant gene from Colletotrichum ...

    African Journals Online (AJOL)

    Cloning of a carbendazim-resistant gene from Colletotrichum gloeosporioides of mango in South China. ... Abstract. Mango anthracnose caused by Colletotrichum gloeosporioides is an important disease and prevalent in tropical regions of China. High carbendazim ... employed to further test the above results. It involved an ...

  13. Cloning and characterization of NBS-LRR resistance gene ...

    African Journals Online (AJOL)

    biotech

    2013-07-03

    Jul 3, 2013 ... Resistance genes honologues I theobroma cacao as useful genetic markers. Theor. Appl. Gent. 107:191-202. Kumar S, Tamura K, Nei M (2004). MEGA3: integrated software for molecular evolutionary genetics analysis and sequence alignment. Brief Bioinform. 5:150-163. Lacock L, Niekerk CV, Loots S, ...

  14. Cloning and characterization of NBS-LRR resistance gene ...

    African Journals Online (AJOL)

    biotech

    2013-07-03

    Jul 3, 2013 ... Full Length Research Paper. Cloning and characterization of NBS-LRR resistance gene analogues of Musa spp. and their expression profiling studies against Pratylenchus coffeae. S. Backiyarani*, S. Uma, G. Arunkumar, M. S. Saraswathi and P. Sundararaju. National Research Centre for Banana (ICAR), ...

  15. Prevalence, antibiotic-resistance properties and enterotoxin gene ...

    African Journals Online (AJOL)

    milk-based infant foods in Iran, represent an important public health issue which should be considered ... Keywords: Prevalence, Bacillus cereus, Antibiotic resistance, Enterotoxigenic genes, Milk-based infant food. Tropical Journal of Pharmaceutical Research is indexed by Science ..... and cereals collected in Korea.

  16. Codon-optimized antibiotic resistance gene improves efficiency of ...

    Indian Academy of Sciences (India)

    We generated a synthetic gentamicin resistance gene whose codon usage is optimized to Frankia (fgmR) and evaluated its usefulness as a selection marker using a transient transformation system. Success rate of transient transformation and cell growth in selective culture were significantly increased by use of fgmR ...

  17. 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 ...

  18. Genetic analysis and location of a resistance gene to Puccinia ...

    Indian Academy of Sciences (India)

    Administrator

    Electrophoresis was carried out at 1400. V for 1.0 - 1.5 h. Gel staining and visualization was done as previously described (Chen et al. 1998). Polymorphic markers were used to genotype the F2 population. Genotype data were used to construct a genetic map and locate the resistance gene. Mapping and Data analysis.

  19. Functional screening of antibiotic resistance genes from human gut microbiota reveals a novel gene fusion.

    Science.gov (United States)

    Cheng, Gong; Hu, Yongfei; Yin, Yeshi; Yang, Xi; Xiang, Chunsheng; Wang, Baohong; Chen, Yanfei; Yang, Fengling; Lei, Fang; Wu, Na; Lu, Na; Li, Jing; Chen, Quanze; Li, Lanjuan; Zhu, Baoli

    2012-11-01

    The human gut microbiota has a high density of bacteria that are considered a reservoir for antibiotic resistance genes (ARGs). In this study, one fosmid metagenomic library generated from the gut microbiota of four healthy humans was used to screen for ARGs against seven antibiotics. Eight new ARGs were obtained: one against amoxicillin, six against d-cycloserine, and one against kanamycin. The new amoxicillin resistance gene encodes a protein with 53% identity to a class D β-lactamase from Riemerella anatipestifer RA-GD. The six new d-cycloserine resistance genes encode proteins with 73-81% identity to known d-alanine-d-alanine ligases. The new kanamycin resistance gene encodes a protein of 274 amino acids with an N-terminus (amino acids 1-189) that has 42% identity to the 6'-aminoglycoside acetyltransferase [AAC(6')] from Enterococcus hirae and a C-terminus (amino acids 190-274) with 35% identity to a hypothetical protein from Clostridiales sp. SSC/2. A functional study on the novel kanamycin resistance gene showed that only the N-terminus conferred kanamycin resistance. Our results showed that functional metagenomics is a useful tool for the identification of new ARGs. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  20. 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

  1. 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.

  2. Identification of antimicrobial resistance genes in multidrug-resistant clinical Bacteroides fragilis isolates by whole genome shotgun sequencing

    DEFF Research Database (Denmark)

    Sydenham, Thomas Vognbjerg; Sóki, József; Hasman, Henrik

    2015-01-01

    Bacteroides fragilis constitutes the most frequent anaerobic bacterium causing bacteremia in humans. The genetic background for antimicrobial resistance in B. fragilis is diverse with some genes requiring insertion sequence (IS) elements inserted upstream for increased expression. To evaluate whole...... genome shotgun sequencing as a method for predicting antimicrobial resistance properties, one meropenem resistant and five multidrug-resistant blood culture isolates were sequenced and antimicrobial resistance genes and IS elements identified using ResFinder 2.1 (http...

  3. Effects of ultraviolet disinfection on antibiotic-resistant Escherichia coli from wastewater: inactivation, antibiotic resistance profiles and antibiotic resistance genes.

    Science.gov (United States)

    Zhang, Chong-Miao; Xu, Li-Mei; Wang, Xiaochang C; Zhuang, Kai; Liu, Qiang-Qiang

    2017-04-29

    To evaluate the effect of ultraviolet (UV) disinfection on antibiotic-resistant Escherichia coli (E. coli). Antibiotic-resistant E. coli strains were isolated from a wastewater treatment plant and subjected to UV disinfection. The effect of UV disinfection on the antibiotic resistance profiles and the antibiotic resistance genes (ARGs) of antibiotic-resistant E. coli was evaluated by a combination of antibiotic susceptibility analysis and molecular methods. Results indicated that multiple-antibiotic-resistant (MAR) E. coli were more resistant at low UV doses and required a higher UV dose (20 mJ cm -2 ) to enter the tailing phase compared with those of antibiotic-sensitive E. coli (8 mJ cm -2 ). UV disinfection caused a selective change in the inhibition zone diameters of surviving antibiotic-resistant E. coli and a slight damage to ARGs. The inhibition zone diameters of the strains resistant to antibiotics were more difficult to alter than those susceptible to antibiotics because of the existence and persistence of corresponding ARGs. The resistance of MAR bacteria to UV disinfection at low UV doses and the changes in inhibition zone diameters could potentially contribute to the selection of ARB in wastewater treatment after UV disinfection. The risk of spread of antibiotic resistance still exists owing to the persistence of ARGs. Our study highlights the acquisition of other methods to control the spread of ARGs. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. 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

  5. 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.

  6. 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

  7. Phylogenetic group, virulence factors and antimicrobial resistance of Escherichia coli associated with bovine mastitis.

    Science.gov (United States)

    Liu, Yongxia; Liu, Gang; Liu, Wenjun; Liu, Yong; Ali, Tariq; Chen, Wei; Yin, Jinhua; Han, Bo

    2014-05-01

    Escherichia coli is an important pathogen involved in the etiology of bovine mastitis. A total of 70 E. coli isolates recovered from clinical and subclinical mastitis samples were characterized with respect to their phylogenic group, virulence factors and antimicrobial susceptibility. Based on the presence of the specific genes chuA, yjaA and TspE4.C2, these isolates were found to belong to three different groups: group A(25), group B1(41) and group D(4). Twenty-five (35.7%) isolates harbored at least one virulence gene, and the most prevalent virulence genes were f17A, irp2, astA, iucD and colV. The irp2-coding gene was more often detected in group A than in group B1 isolates; in contrast, colV was identified more often in group B1 isolates. The majority of isolates (87.1%) were resistant to at least one antimicrobial compound. Forty-seven isolates (67.1%) were resistant to streptomycin, and those from group B1 were more resistant to streptomycin than isolates from group A. The latter feature was supported by the distribution of streptomycin resistance genes observed in group B1 compared to group A. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  8. 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...... with decreased sensitivity to amodiaquine and lumefantrine, but effects of these polymorphisms on therapeutic responses to artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) have not been clearly defined. Individual patient data from 31 clinical trials were harmonized and pooled by using standardized...

  9. Recombination Rate Heterogeneity within Arabidopsis Disease Resistance Genes.

    Science.gov (United States)

    Choi, Kyuha; Reinhard, Carsten; Serra, Heïdi; Ziolkowski, Piotr A; Underwood, Charles J; Zhao, Xiaohui; Hardcastle, Thomas J; Yelina, Nataliya E; Griffin, Catherine; Jackson, Matthew; Mézard, Christine; McVean, Gil; Copenhaver, Gregory P; Henderson, Ian R

    2016-07-01

    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.

  10. 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.

  11. Persistence of antimicrobial resistance genes from sows to finisher pigs

    DEFF Research Database (Denmark)

    Birkegård, Anna Camilla; Halasa, Tariq; Folkesson, Anders

    2018-01-01

    Antimicrobial resistance in pigs has been under scrutiny for many years. However, many questions remain unanswered, including whether the initial antimicrobial resistance level of a pig will influence the antimicrobial resistance found at slaughter. Faecal samples from finishers pigs from 681 farms...... and from sows from 82 farms were collected, and levels of seven antimicrobial resistance genes, ermB, ermF, sulI, sulII, tet(M), tet(O), and tet(W), were quantified by high-capacity qPCR. There were 40 pairs of observations where the finishers were born in the farms of the sows. The objective of this study...... was to evaluate whether the levels of AMR genes found in finisher pigs at slaughter were associated with the levels in the farm where the finishers were born, and whether the levels of the AMR genes were equal in the sow and finisher pig populations. We found a significant positive correlation between the levels...

  12. De klinische betekenis van de serumconcentraties van isonicotinezuurhydrazide en streptomycine

    NARCIS (Netherlands)

    Graaff, J.L. de

    1965-01-01

    SAMENVATTING EN CONCLUSIES In dit proefschrift worden de resultaten beschreven van een onderzoek naar de invloed van de serumconcentraties van isonicotine- zuurhydrazide (INH) op de therapeutische resultaten bij patienten met longtuberculose. Ook de serumconcentraties van streptomycine (SM) zijn het

  13. 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...

  14. Resistance-Gene Cassettes Associated With Salmonella enterica Genotypes.

    Science.gov (United States)

    Bakhshi, Bita; Ghafari, Mohsen; Pourshafie, Mohammad R; Zarbakhsh, Behnaz; Katouli, Mohammad; Rahbar, Mohammad; Hajia, Masoud; Hosseini-Aliabad, Neda; Boustanshenas, Mina

    2015-01-01

    The epidemiology of salmonellosis is complex because of the diversity and different serotypes of Salmonella enterica (S. enterica) that occur in different reservoirs and geographic incidences. To determine the genotype distribution and resistance-gene content of 2 classes of integron among S. enterica isolates. Thirty-six S. enterica species were isolated and tested for their serological distribution and the resistance-gene contents of 2 classes of integron, as well as for their genetic diversity, using the pulsed-field gel electrophoresis (PFGE) genotyping method. Serogroups E (36.1%) and D (30.5%) were dominant among the isolates. All of the isolates in serogroup D belonged to the serovar enteritidis. The aadA1 gene was found within all resistance-gene cassettes. We observed 4 common and 26 single pulsotypes among the isolates, which indicated a high degree of genetic diversity among the isolates. Using the PulseNet International standard protocol, it was found that these isolates were different from those reported previously in Iran. The presence of a few common and new pulsotypes among the isolates suggests the emergence and spread of new clones of S. enterica in Iran. Copyright© by the American Society for Clinical Pathology (ASCP).

  15. 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.

  16. Resistance gene transfer during treatments for experimental avian colibacillosis.

    Science.gov (United States)

    Dheilly, Alexandra; Le Devendec, Laëtitia; Mourand, Gwenaëlle; Bouder, Axelle; Jouy, Eric; Kempf, Isabelle

    2012-01-01

    An experiment was conducted in animal facilities to compare the impacts of four avian colibacillosis treatments-oxytetracycline (OTC), trimethoprim-sulfadimethoxine (SXT), amoxicillin (AMX), or enrofloxacin (ENR)-on the susceptibility of Escherichia coli in broiler intestinal tracts. Birds were first orally inoculated with rifampin-resistant E. coli strains bearing plasmid genes conferring resistance to fluoroquinolones (qnr), cephalosporins (bla(CTX-M) or bla(FOX)), trimethoprim-sulfonamides, aminoglycosides, or tetracyclines. Feces samples were collected before, during, and after antimicrobial treatments. The susceptibilities of E. coli strains were studied, and resistance gene transfer was analyzed. An increase in the tetracycline-resistant E. coli population was observed only in OTC-treated birds, whereas multiresistant E. coli was detected in the dominant E. coli populations of SXT-, AMX-, or ENR-treated birds. Most multiresistant E. coli strains were susceptible to rifampin and exhibited various pulsed-field gel electrophoresis profiles, suggesting the transfer of one of the multiresistance plasmids from the inoculated strains to other E. coli strains in the intestinal tract. In conclusion, this study clearly illustrates how, in E. coli, "old" antimicrobials may coselect antimicrobial resistance to recent and critical molecules.

  17. The Effects of Hyperbaric Oxygen Therapy Against Streptomycin Ototoxicity

    Directory of Open Access Journals (Sweden)

    Salih Bakir

    2013-10-01

    Full Text Available Aim: Hyperbaric oxygen (HBO is an important adjuvant therapy and being increasingly used in the treatment of various disorders because of having an important antioxidant activity. This experimental study was designed to determine the possible protective effect of HBO therapy on streptomycin-induced ototoxicity. Material and Method: Twenty-eight adult Wistar albino rats were divided into four groups: Streptomycin (n=7, saline (n=7, HBO (n=7, and streptomycin plus HBO (n=7. The HBO administered rats were placed into a large pressure chamber and received 100% oxygene at 2.5 atmosphere absolute for 60 minutes per day in a period of seven days. Rats were tested with DPOAE (Distortion Product Otoacoustic Emissions in the beginning and the end of study. The animals in all groups were sacrificed under general anesthesia on the seventh day. Biopsy specimens from inner ear were stored for histopathologic examination with hematoxylin and eosin (H&E under light microscopy. Results: Outer hair cells shown by light microscopic images were mostly preserved in control and HBO group. DPOAE measurements revealed no significant differences between the beginning and the end (p>0.05. Streptomycin and streptomycin plus HBO treated rats showed loss of hair cells and auditory functions significantly (p<0.05. Between the groups of streptomycin and streptomycin plus HBO; there was no statistically significance according to the analysis of the histopathological scores and DPgram results (p>0.05. Discussion: HBO has probably no harmful effect on hair cells. But it seems to be not beneficial in a streptomycin-induced cochlear damage rat model.

  18. Gene Prioritization of Resistant Rice Gene against Xanthomas oryzae pv. oryzae by Using Text Mining Technologies

    Directory of Open Access Journals (Sweden)

    Jingbo Xia

    2013-01-01

    Full Text Available To effectively assess the possibility of the unknown rice protein resistant to Xanthomonas oryzae pv. oryzae, a hybrid strategy is proposed to enhance gene prioritization by combining text mining technologies with a sequence-based approach. The text mining technique of term frequency inverse document frequency is used to measure the importance of distinguished terms which reflect biomedical activity in rice before candidate genes are screened and vital terms are produced. Afterwards, a built-in classifier under the chaos games representation algorithm is used to sieve the best possible candidate gene. Our experiment results show that the combination of these two methods achieves enhanced gene prioritization.

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

    Czech Academy of Sciences Publication Activity Database

    Kyselková, Martina; Jirout, Jiří; Vrchotová, Naděžda; Schmitt, H.; Elhottová, Dana

    2015-01-01

    Roč. 6, may (2015), s. 536 ISSN 1664-302X R&D Projects: GA ČR GAP504/10/2077; GA MŠk(CZ) EE2.3.30.0032; GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 ; RVO:60077344 Keywords : antibiotic resistance spread * animal manure * cattle intestinal microflora * chlortetracycline * dairy cattle * dairy farm * heavy metals * tetracycline resistance genes Subject RIV: EI - Biotechnology ; Bionics; EE - Microbiology, Virology (BC-A) Impact factor: 4.165, year: 2015

  20. Phenotypic and genotypic characteristics of antibiotic resistance of commensal Escherichia coli isolates from healthy pigs

    Directory of Open Access Journals (Sweden)

    Mazurek Justyna

    2014-06-01

    Full Text Available The objective of the study was to examine the characteristics of the resistance profiles of Escherichia coli isolated from healthy pigs from three farms in Western Poland. The sensitivity to 13 antimicrobial agents was tested by a disk diffusion method, and the presence of 13 resistance genes was determined by PCR. The majority of the isolates were multi-resistant. The most common multi-resistance patterns were streptomycin, trimethoprim, sulfisoxazole, ampicillin, tetracycline. Although some resistance genes, such as strA/strB, blaTEM, sul1, sul2, and tetA, were equally represented in isolates from each farm, differences in the distribution of tetB and tetC, hfrV, dhfrXII, and sul1 resistance genes were observed among the isolates from different farms. Approximately one-third (35.9% of the isolates possessed a class 1 integron. The four major different variable regions of the class 1 integron contained streptomycin (aadA1, aadA2, and aadA5 and/or trimethoprim (dhfrI, dhfrV and dhfrXVII, and/or sulphonamides (sul1 resistance genes. The results of this study emphasise that uncontrolled use of antibiotics causes the development of resistance and provides the evidence of frequent occurrence of more than one gene encoding the resistance to the same antimicrobial agent in the multi-resistant strains.

  1. Using SNP genetic markers to elucidate the linkage of the Co-34/Phg-3 anthracnose and angular leaf spot resistance gene cluster with the Ur-14 resistance gene

    Science.gov (United States)

    The Ouro Negro common bean cultivar contains the Co-34/Phg-3 gene cluster that confers resistance to the anthracnose (ANT) and angular leaf spot (ALS) pathogens. These genes are tightly linked on chromosome 4. Ouro Negro also has the Ur-14 rust resistance gene, reportedly in the vicinity of Co- 34; ...

  2. Thermal Degradation of Streptomycin Residues in Honey During Storage

    Directory of Open Access Journals (Sweden)

    Monica Cristina Cara

    2013-01-01

    Full Text Available In Europe there is an increasing emphasis on the quality control of honey, especially on maximum limits of veterinary drug residues (particularly antibiotics permitted in it. Streptomycin is an aminoglycoside antibiotic used in apiculture to protect bees against a variety of brood diseases. Romanian authorities have included it in the National Monitoring Program for honey manufacturers. In this study, an enzyme-linked immunosorbent assay (ELISA screening test was validated as a detection method of streptomycin residues in honey. The ELISA experimental results were compared to those obtained by using an HPLC method. The values generated by the two methods were very close to each other. This fact certifies that ELISA method can be successfully used for quantitative detection of the amount of streptomycin in honey samples. Following validation, three types of honey (polyfloral, lime and acacia were analyzed for streptomycin content after exposure to 4, 22, 30, 40 or 70 °C for 20 weeks. The results show that streptomycin mass fraction decreased with time and with the increase of temperature in all honey samples. The data collected were used to fit a second-order multiple linear regression model for predicting the degradation of streptomycin in honey samples as a function of temperature and storage period. Values of the calculated statistical indicators confirm a good predictive capability of mathematical and statistical models.

  3. A role for Tn6029 in the evolution of the complex antibiotic resistance gene loci in genomic island 3 in enteroaggregative hemorrhagic Escherichia coli O104:H4.

    Directory of Open Access Journals (Sweden)

    Piklu Roy Chowdhury

    Full Text Available In enteroaggregative hemorrhagic Escherichia coli (EAHEC O104 the complex antibiotic resistance gene loci (CRL found in the region of divergence 1 (RD1 within E. coli genomic island 3 (GI3 contains blaTEM-1, strAB, sul2, tet(AA, and dfrA7 genes encoding resistance to ampicillin, streptomycin, sulfamethoxazole, tetracycline and trimethoprim respectively. The precise arrangement of antibiotic resistance genes and the role of mobile elements that drove the evolutionary events and created the CRL have not been investigated. We used a combination of bioinformatics and iterative BLASTn searches to determine the micro-evolutionary events that likely led to the formation of the CRL in GI3 using the closed genome sequences of EAHEC O104:H4 strains 2011C-3493 and 2009EL-2050 and high quality draft genomes of EAHEC E. coli O104:H4 isolates from sporadic cases not associated with the initial outbreak. Our analyses indicate that the CRL in GI3 evolved from a progenitor structure that contained an In2-derived class 1 integron in a Tn21/Tn1721 hybrid backbone. Within the hybrid backbone, a Tn6029-family transposon, identified here as Tn6029C abuts the sul1 gene in the 3'-Conserved Segment (-CS of a class 1 integron generating a unique molecular signature that has only previously been observed in pASL01a, a small plasmid found in commensal E. coli in West Africa. From this common progenitor, independent IS26-mediated events created two novel transposons identified here as Tn6029D and Tn6222 in 2011C-3493 and 2009EL-2050 respectively. Analysis of RD1 within GI3 reveals IS26 has played a crucial role in the assembly of regions within the CRL.

  4. Source-Related Effects of Wastewater on Transcription Factor (AhR, CAR and PXR-Mediated Induction of Gene Expression in Cultured Rat Hepatocytes and Their Association with the Prevalence of Antimicrobial-Resistant Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Keerthi S Guruge

    Full Text Available Extracts of wastewater collected from 4 sewage treatment plants (STPs receiving effluents from different sources in South India were investigated for their levels of transcription factor-mediated gene induction in primary cultured rat hepatocytes. In addition, the relation between gene induction levels and the prevalence of antimicrobial-resistant Escherichia coli (E. coli in wastewater was examined. STP-3, which treats only hospital wastewater, exhibited significantly greater induction potency of all 6 drug metabolizing cytochrome P450 (CYP genes examined, CYP1A1, 1A2, 1B1, 2B15, 3A1, and 3A2, whereas the wastewater at STP-1, which exclusively receives domestic sewage, showed significantly diminished levels of induction of 3 CYP genes when compared to the levels of CYP induction at STP-2, which receives mixed wastewater. Samples collected during the monsoon season showed a significantly altered gene induction capacity compared to that of samples from the pre-monsoon period. The data suggest that the toxicity of wastewater in STPs was not significantly diminished during the treatment process. The chemical-gene interaction data predicted that a vast number of chemicals present in the wastewater would stimulate the genes studied in the rat hepatocytes. The multivariable logistic regression analysis demonstrated that the prevalence of isolates resistant to cefotaxime, imipenem and streptomycin was significantly correlated with the levels of induction of at least three CYP-isozymes in STP wastewater. In addition, the resistance of isolates in treatment plants was not altered by the treatment steps, whereas the sampling season did have an impact on the resistance to specific antimicrobials. The identification of receptor-mediated gene regulation capacities offers important data not limited to the (synergistic physiological role of chemicals in biological systems but may provide new insight into the link between the effects of known/unknown drugs and

  5. Source-Related Effects of Wastewater on Transcription Factor (AhR, CAR and PXR)-Mediated Induction of Gene Expression in Cultured Rat Hepatocytes and Their Association with the Prevalence of Antimicrobial-Resistant Escherichia coli

    Science.gov (United States)

    Guruge, Keerthi S.; Yamanaka, Noriko; Sonobe, Miyuki; Fujizono, Wataru; Yoshioka, Miyako; Akiba, Masato; Yamamoto, Takehisa; Joshua, Derrick I.; Balakrishna, Keshava; Yamashita, Nobuyoshi; Kannan, Kurunthachalam; Tsutsui, Toshiyuki

    2015-01-01

    Extracts of wastewater collected from 4 sewage treatment plants (STPs) receiving effluents from different sources in South India were investigated for their levels of transcription factor-mediated gene induction in primary cultured rat hepatocytes. In addition, the relation between gene induction levels and the prevalence of antimicrobial-resistant Escherichia coli (E. coli) in wastewater was examined. STP-3, which treats only hospital wastewater, exhibited significantly greater induction potency of all 6 drug metabolizing cytochrome P450 (CYP) genes examined, CYP1A1, 1A2, 1B1, 2B15, 3A1, and 3A2, whereas the wastewater at STP-1, which exclusively receives domestic sewage, showed significantly diminished levels of induction of 3 CYP genes when compared to the levels of CYP induction at STP-2, which receives mixed wastewater. Samples collected during the monsoon season showed a significantly altered gene induction capacity compared to that of samples from the pre-monsoon period. The data suggest that the toxicity of wastewater in STPs was not significantly diminished during the treatment process. The chemical-gene interaction data predicted that a vast number of chemicals present in the wastewater would stimulate the genes studied in the rat hepatocytes. The multivariable logistic regression analysis demonstrated that the prevalence of isolates resistant to cefotaxime, imipenem and streptomycin was significantly correlated with the levels of induction of at least three CYP-isozymes in STP wastewater. In addition, the resistance of isolates in treatment plants was not altered by the treatment steps, whereas the sampling season did have an impact on the resistance to specific antimicrobials. The identification of receptor-mediated gene regulation capacities offers important data not limited to the (synergistic) physiological role of chemicals in biological systems but may provide new insight into the link between the effects of known/unknown drugs and prevalence of

  6. 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.

  7. 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 (Pantibiotic resistance genes distribution in MBRs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Resistance among Escherichia coli to sulphonamides and other antimicrobials now little used in man.

    Science.gov (United States)

    Bean, David C; Livermore, David M; Papa, Iro; Hall, Lucinda M C

    2005-11-01

    We investigated whether sulphonamide resistance in Escherichia coli remained prevalent in 2004, 9 years since the formal introduction of a UK prescribing restriction on co-trimoxazole. Resistance to other agents no longer in common use was also examined. Consecutive urinary E. coli isolates were obtained at the diagnostic microbiology laboratory of the Royal London Hospital from January to March 2004. The presence of the sulphonamide resistance genes, sul1, sul2 and sul3, and the class I integrase gene, int1, were determined by PCR. Of the 391 E. coli isolates recovered in 2004, 45.5% were sulphonamide-resistant compared with 46.0% in 1999 and 39.7% in 1991. The sul2 gene remained the most prevalent sulphonamide resistance determinant, present in 81% of resistant isolates in 2004 compared with 79% and 67% in 1999 and 1991, respectively; 28% of resistant isolates carried both sul1 and sul2 genes; sul3 was not found. Resistance to streptomycin also remained common, whereas resistance to chloramphenicol and kanamycin had decreased since 1999. Sulphonamide resistance in E. coli persists undiminished despite the prolonged withdrawal of this antibiotic in the UK; resistance to streptomycin also seems stable whilst that to chloramphenicol and kanamycin is declining.

  10. Transcriptome analyses and virus induced gene silencing identify genes in the Rpp4-mediated Asian soybean rust resistance pathway

    Science.gov (United States)

    Rpp4 (Resistance to Phakopsora pachyrhizi 4) confers resistance to P. pachyrhizi, the causal agent of Asian soybean rust (ASR). By combining expression profiling and virus induced gene silencing (VIGS), we are developing a genetic framework for Rpp4-mediated resistance. We measured gene expression i...

  11. Fate and transport of antibiotic resistant bacteria and resistance genes in artificially drained agricultural fields receiving swine manure application

    Science.gov (United States)

    While previous studies have examined the occurrence of antibiotic resistant bacteria and antibiotic resistant genes around confined swine feeding operations, little information is known about their release and transport from artificially drained fields receiving swine manure application. Much of the...

  12. A novel resistance gene, lnu(H), conferring resistance to lincosamides in Riemerella anatipestifer CH-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

    2018-01-01

    The Gram-negative bacterium Riemerella anatipestifer CH-2 is resistant to lincosamides, having a lincomycin (LCM) minimum inhibitory concentration (MIC) of 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 nucleotidylyltransferases. Escherichia coli Rosetta TM (DE3) containing the pBAD24-lnu(H) plasmid showed four- and two-fold increases in the MICs of LCM and clindamycin (CLI), respectively. A kinetic assay of the purified Lnu(H) enzyme for LCM and CLI showed that the protein could inactive lincosamides. Mass spectrometry analysis demonstrated that the Lnu(H) enzyme catalysed adenylylation of lincosamides. In addition, an lnu(H) gene deletion strain exhibited 512- and 32-fold decreases in LCM and CLI MICs, respectively. The wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu(H) gene. The transformant R. anatipestifer ATCC 11845 [lnu(H)] acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, among 175 R. anatipestifer field isolates, 56 (32.0%) were positive for the lnu(H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidylyltransferase that inactivates LCM and CLI by nucleotidylylation, thus conferring high-level lincosamide resistance to R. anatipestifer CH-2. Copyright © 2017. Published by Elsevier B.V.

  13. 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...

  14. A high prevalence of antimicrobial resistant Escherichia coli isolated from pigs and a low prevalence of antimicrobial resistant E. coli from cattle and sheep in Great Britain at slaughter.

    Science.gov (United States)

    Enne, Virve I; Cassar, Claire; Sprigings, Katherine; Woodward, Martin J; Bennett, Peter M

    2008-01-01

    The incidence of antimicrobial resistance and expressed and unexpressed resistance genes among commensal Escherichia coli isolated from healthy farm animals at slaughter in Great Britain was investigated. The prevalence of antimicrobial resistance among the isolates varied according to the animal species; of 836 isolates from cattle tested only 5.7% were resistant to one or more antimicrobials, while only 3.0% of 836 isolates from sheep were resistant to one or more agents. However, 92.1% of 2480 isolates from pigs were resistant to at least one antimicrobial. Among isolates from pigs, resistance to some antimicrobials such as tetracycline (78.7%), sulphonamide (66.9%) and streptomycin (37.5%) was found to be common, but relatively rare to other agents such as amikacin (0.1%), ceftazidime (0.1%) and coamoxiclav (0.2%). The isolates had a diverse range of resistance gene profiles, with tet(B), sul2 and strAB identified most frequently. Seven out of 615 isolates investigated carried unexpressed resistance genes. One trimethoprim-susceptible isolate carried a complete dfrA17 gene but lacked a promoter for it. However, in the remaining six streptomycin-susceptible isolates, one of which carried strAB while the others carried aadA, no mutations or deletions in gene or promoter sequences were identified to account for susceptibility. The data indicate that antimicrobial resistance in E. coli of animal origin is due to a broad range of acquired genes.

  15. 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

  16. 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.

  17. 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...

  18. 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.

  19. Transport of tylosin and tylosin-resistance genes in subsurface drainage water from manured fields

    Science.gov (United States)

    Animal agriculture appears to contribute to the spread of antibiotic resistance genes, but few studies have quantified gene transport in agricultural fields. The transport of tylosin, tylosin-resistance genes (erm B, F, A) and tylosin-resistant Enterococcus were measured in tile drainage water from ...

  20. 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

    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......, 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...

  1. 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.

  2. Expression levels of resistant genes affect cervical cancer prognosis.

    Science.gov (United States)

    Yang, Fengmei; Gao, Bo; Li, Rui; Li, Wencui; Chen, Wei; Yu, Zongtao; Zhang, Jicai

    2017-05-01

    Tumor cells may develop multidrug resistance (MDR) to various chemotherapy regimens. Such resistance reduces the sensitivity of cells to chemotherapy drugs, leading to the failure of cervical cancer (CC) treatment and disease progression. The present study aimed to investigate the role of MDR1, lung resistance protein (LRP) and placental glutathione S‑transferase π 1 (GSTP1) in CC and MDR, and the prognostic value of these genes. The mRNA expression levels of these resistance‑associated genes were determined in 47 CC and 20 healthy cervical tissue samples. Subsequently, the data was analyzed alongside clinicopathological parameters. The mRNA expression levels of MDR1, LRP and GSTP1 in CC were 0.57±0.32, 0.58±0.29 and 0.44±0.24, respectively, whereas those in healthy cervical tissues were 0.19±0.10, 0.17±0.14 and 0.18±0.10, respectively. Therefore, the expression levels of these genes were significantly greater in CC compared with healthy cervical tissue (PMRD1 were increased in the well differentiated group (0.68±0.27) compared with the poorly differentiated group (0.38±0.33; P0.05). Multivariate logistic regression indicated that the degree of differentiation and the MDR1 gene expression levels were predictors of CC prognosis (P<0.05). The survival rate of patients in the MDR1‑negative group was significantly greater compared with the MDR1‑positive group (P<0.05). The results of the present study therefore suggested that MDR1 gene expression is a predictor of poor survival in CC.

  3. Identification of Gene Resistance to Avian InfluenzaVirus (Mx Gene among Wild Waterbirds

    Directory of Open Access Journals (Sweden)

    Dewi Elfidasari

    2013-04-01

    Full Text Available The Mx gene is an antiviral gene used to determine the resistance or the susceptibility to different types of viruses, including the Avian Influenza (AI virus subtype H5N1. The AI virus subtype H5N1 infection in chickens causes Mx gene polymorphism. The Mx+ gene shows resistant to the AIvirus subtype H5N1, whereas the Mx-gene shows signs of susceptible. The objective of thisresearch was to detect the Mxgene in wild aquatic birds using the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP method with the primer pairs F2 and NE-R2/R and the RsaI restriction enzyme. DNA samples were obtained from eight species of wild waterbirds with positive and negative exposure to the AI virus subtype H5N1. DNA amplification results showed that the Mxgene in wild aquatic birds is found in a 100 bp fragment, which is the same as the Mx gene found in chickens. However, unlike chickens, the Mxgene in wild aquatic birds did not show any polymorphism. This study proves that Mx- based resistance to AI virus subtype H5N1 in different in wild birds than in chickens.

  4. Evaluation of a model for Escherichia coli O157:H7 colonization in streptomycin-treated adult cattle.

    Science.gov (United States)

    Snider, Timothy A; Fabich, Andrew J; Washburn, Kevin E; Sims, Will P; Blair, Jeffrey L; Cohen, Paul S; Conway, Tyrrell; Clinkenbeard, Kenneth D

    2006-11-01

    To develop a repeatable model for studying colonization with streptomycin-resistant Escherichia coli O157:H7 in adult cattle. 5 adult mixed-breed beef cattle. Cattle were surgically cannulated in the duodenum, treated daily with streptomycin (33 mg/kg) via the duodenal cannula prior to and during experimental colonizations, and colonized with 10(10) CFUs of streptomycin-resistant E coli O157:H7 via the duodenal cannula. Colonization of rectal mucus and shedding in feces were monitored. Antimicrobials were administered to eliminate the colonizing strain so that 5 repeated colonization experiments could be performed. A comprehensive analysis of colonization was performed at necropsy. Streptomycin treatment resulted in improved experimental colonization variables, compared with untreated controls, during initiation (days 2 to 6) and early maintenance (days 7 to 12) of colonization. Elimination of the colonizing strain followed by 5 repeated colonizations in the same animals indicated the repeatability of the protocol. Positive results of bacteriologic culture of feces 7 and 12 days after colonization were obtained in 100% and 84% of samples, respectively, across all animals and trials. At necropsy, highest magnitude recovery was in terminal rectal mucus. The model was highly repeatable and novel with respect to streptomycin treatment, use of duodenal cannulas, and repeated colonizations of the same animals. Its use in adult cattle, from which most bovine-derived food originates, is critical to the study of preharvest food safety. The findings have implications for understanding intermittency of shedding in the field and for proposed vaccine-based interventions.

  5. 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.

  6. Resistance gene homologues in melon are linked to genetic loci conferring disease and pest resistance.

    Science.gov (United States)

    Brotman, Y.; Silberstein, L.; Kovalski, I.; Perin, C.; Dogimont, C.; Pitrat, M.; Klingler, J.; Thompson, A.; Perl-Treves, R.

    2002-05-01

    Genomic and cDNA fragments with homology to known disease resistance genes (RGH fragments) were cloned from Cucumis melo using degenerate-primer PCR. Fifteen homologues of the NBS-LRR gene family have been isolated. The NBS-LRR homologues show high divergence and, based on the partial NBS-fragment sequences, appear to include members of the two major subfamilies that have been described in dicot plants, one that possesses a TIR-protein element and one that lacks such a domain. Genomic organization of these sequences was explored by DNA gel-blot analysis, and conservation among other Cucurbitaceae was assessed. Two mapping populations that segregate for several disease and pest resistance loci were used to map the RGH probes onto the melon genetic map. Several NBS-LRR related sequences mapped to the vicinity of genetic loci that control resistance to papaya ringspot virus, Fusarium oxysporum race 1, F. oxysporum race 2 and to the insect pest Aphis gossypii. The utility of such markers for breeding resistant melon cultivars and for cloning the respective R-genes is discussed.

  7. A Novel Phytophthora sojae Resistance Rps12 Gene Mapped to a Genomic Region That Contains Several Rps Genes.

    Science.gov (United States)

    Sahoo, Dipak K; Abeysekara, Nilwala S; Cianzio, Silvia R; Robertson, Alison E; Bhattacharyya, Madan K

    2017-01-01

    Phytophthora sojae Kaufmann and Gerdemann, which causes Phytophthora root rot, is a widespread pathogen that limits soybean production worldwide. Development of Phytophthora resistant cultivars carrying Phytophthora resistance Rps genes is a cost-effective approach in controlling this disease. For this mapping study of a novel Rps gene, 290 recombinant inbred lines (RILs) (F7 families) were developed by crossing the P. sojae resistant cultivar PI399036 with the P. sojae susceptible AR2 line, and were phenotyped for responses to a mixture of three P. sojae isolates that overcome most of the known Rps genes. Of these 290 RILs, 130 were homozygous resistant, 12 heterzygous and segregating for Phytophthora resistance, and 148 were recessive homozygous and susceptible. From this population, 59 RILs homozygous for Phytophthora sojae resistance and 61 susceptible to a mixture of P. sojae isolates R17 and Val12-11 or P7074 that overcome resistance encoded by known Rps genes mapped to Chromosome 18 were selected for mapping novel Rps gene. A single gene accounted for the 1:1 segregation of resistance and susceptibility among the RILs. The gene encoding the Phytophthora resistance mapped to a 5.8 cM interval between the SSR markers BARCSOYSSR_18_1840 and Sat_064 located in the lower arm of Chromosome 18. The gene is mapped 2.2 cM proximal to the NBSRps4/6-like sequence that was reported to co-segregate with the Phytophthora resistance genes Rps4 and Rps6. The gene is mapped to a highly recombinogenic, gene-rich genomic region carrying several nucleotide binding site-leucine rich repeat (NBS-LRR)-like genes. We named this novel gene as Rps12, which is expected to be an invaluable resource in breeding soybeans for Phytophthora resistance.

  8. A Novel Phytophthora sojae Resistance Rps12 Gene Mapped to a Genomic Region That Contains Several Rps Genes.

    Directory of Open Access Journals (Sweden)

    Dipak K Sahoo

    Full Text Available Phytophthora sojae Kaufmann and Gerdemann, which causes Phytophthora root rot, is a widespread pathogen that limits soybean production worldwide. Development of Phytophthora resistant cultivars carrying Phytophthora resistance Rps genes is a cost-effective approach in controlling this disease. For this mapping study of a novel Rps gene, 290 recombinant inbred lines (RILs (F7 families were developed by crossing the P. sojae resistant cultivar PI399036 with the P. sojae susceptible AR2 line, and were phenotyped for responses to a mixture of three P. sojae isolates that overcome most of the known Rps genes. Of these 290 RILs, 130 were homozygous resistant, 12 heterzygous and segregating for Phytophthora resistance, and 148 were recessive homozygous and susceptible. From this population, 59 RILs homozygous for Phytophthora sojae resistance and 61 susceptible to a mixture of P. sojae isolates R17 and Val12-11 or P7074 that overcome resistance encoded by known Rps genes mapped to Chromosome 18 were selected for mapping novel Rps gene. A single gene accounted for the 1:1 segregation of resistance and susceptibility among the RILs. The gene encoding the Phytophthora resistance mapped to a 5.8 cM interval between the SSR markers BARCSOYSSR_18_1840 and Sat_064 located in the lower arm of Chromosome 18. The gene is mapped 2.2 cM proximal to the NBSRps4/6-like sequence that was reported to co-segregate with the Phytophthora resistance genes Rps4 and Rps6. The gene is mapped to a highly recombinogenic, gene-rich genomic region carrying several nucleotide binding site-leucine rich repeat (NBS-LRR-like genes. We named this novel gene as Rps12, which is expected to be an invaluable resource in breeding soybeans for Phytophthora resistance.

  9. [State-of-the-art status on airborne antibiotic resistant bacteria and antibiotic resistance genes].

    Science.gov (United States)

    Li, J; Yao, M S

    2018-04-06

    The world is facing more deaths due to increasing antibiotic-resistant bacterial infections and the shortage of new highly effective antibiotics, however the air media as its important transmission route has not been adequately studied. Based on the latest literature acquired in this work, we have discussed the state-of-the-art research progress of the concentration, distribution and spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in different environmental air media, and also analyzed some future prevention and control measures. The large use of antibiotics in the medical settings and animal husbandry places has resulted in higher abundances of ARB and ARGs in the relevant and surrounding atmosphere than in urban and general indoor air environments. ARGs can be spread by adhering to airborne particles, and researchers have also found that air media contain more abundant ARGs than other environmental media such as soil, water and sediment. It was suggested in this review that strengthening the monitoring, study on spreading factors and biological toxicity, and also research and development on pathogen accurate diagnosis and new green antibiotic are expected to help effectively monitor, prevent and control of the impacts of airborne resistant bacteria and resistance genes on both human and ecologies.

  10. 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

  11. The consequences of a sudden demographic change on the seroprevalence pattern, virulence genes, identification and characterisation of integron-mediated antibiotic resistance in the Salmonella enterica isolated from clinically diarrhoeic humans in Egypt.

    Science.gov (United States)

    Osman, K M; Hassan, W M M; Mohamed, R A H

    2014-08-01

    The present study was undertaken to identify and characterise integrons and integrated resistance gene cassettes among eight multidrug-resistant (MDR) Salmonella serovars isolated from humans in Egypt. Virulotyping by polymerase chain reaction (PCR) was used for the detection of the presence of virulence genes. Integron PCR was used to detect the presence of class 1 in the MDR strains. The associated individual resistance gene cassettes were identified using specific PCRs. The isolated serovars were Salmonella Grampian (C1; 2/5), Larose (C1; 1/5), Hato (B; 1/5) and Texas (B; 1/5). Among the Salmonella serovars, five Salmonella isolates showed the highest resistance to amoxicillin, ampicillin, chloramphenicol, lincomycin, gentamicin, nalidixic acid, streptomycin and trimethoprim (100%), followed by neomycin, norfloxacin and tetracycline (80%), while the lowest resistance was recorded to colistin sulphate and ciprofloxacin in percentages of 20 and 40%, respectively. The invA, avrA, ssaQ, mgtC, siiD and sopB genes were detected in all isolates (100%), while the spvC and gipA genes were totally (100%) absent from all isolates. The remaining three virulence genes were diversely distributed as follows: the bcfC gene was detected in all isolates except Salmonella Hato (80%); the sodC1 gene was detected only in Salmonella Grampian and Salmonella Texas (60%); and the sopE1 gene was detected only in Salmonella Grampian, Hato and Texas (60%). Class 1 integrons were detected in 90% of the MDR isolates, comprising serovars Muenster, Florian, Noya, Grampian, Larose, Hato and Texas. Of the class 1 integron-positive isolates, 45% harboured Salmonella genomic island 1 (SGI1) either right junction or right and left junction having an A-C-S-T phenotype. Of the class 1 integron-positive isolates, 44% harboured integron gene cassette aadA2, while 11% harboured the floR gene present in multidrug resistance flanked by two integrons of SGI1. The results of the present study indicate that

  12. Study on drug resistance of mycobacterium tuberculosis in patients with pulmonary tuberculosis by drug resistance gene detecting

    International Nuclear Information System (INIS)

    Wang Wei; Li Hongmin; Wu Xueqiong; Wang Ansheng; Ye Yixiu; Wang Zhongyuan; Liu Jinwei; Chen Hongbing; Lin Minggui; Wang Jinhe; Li Sumei; Jiang Ping; Feng Bai; Chen Dongjing

    2004-01-01

    To investigate drug resistance of mycobacterium tuberculosis in different age group, compare detecting effect of two methods and evaluate their the clinical application value, all of the strains of mycobacterium tuberculosis were tested for resistance to RFP, INH SM PZA and EMB by the absolute concentration method on Lowenstein-Jensen medium and the mutation of the rpoB, katG, rpsL, pncA and embB resistance genes in M. tuberculosis was tested by PCR-SSCP. In youth, middle and old age group, the rate of acquired drug resistance was 89.2%, 85.3% and 67.6% respectively, the gene mutation rate was 76.2%, 81.3% and 63.2% respectively. The rate of acquired drug resistance and multiple drug resistance in youth group was much higher than those in other groups. The gene mutation was correlated with drug resistance level of mycobacterium tuberculosis. The gene mutation rate was higher in strains isolated from high concentration resistance than those in strains isolated from low concentration resistance. The more irregular treatment was longer, the rate of drug resistance was higher. Acquired drug resistance varies in different age group. It suggested that surveillance of drug resistence in different age group should be taken seriously, especially in youth group. PCR - SSCP is a sensitive and specific method for rapid detecting rpoB, katG, rpsL, pncA and embB genes mutations of MTB. (authors)

  13. Incidence of antimicrobial-resistance genes and integrons in antibiotic-resistant bacteria isolated from eels and aquaculture ponds.

    Science.gov (United States)

    Lin, Mao; Wu, Xiaomei; Yan, Qingpi; Ma, Ying; Huang, Lixing; Qin, Yingxue; Xu, Xiaojin

    2016-07-07

    The overuse of antimicrobials in aquaculture has promoted the selection of antimicrobial-resistant bacteria. Here we investigated the abundance of antimicrobial-resistance genes and integrons in 108 strains of antibiotic-resistant bacteria isolated from eels and aquaculture ponds in China. Conventional PCR was implemented to examine common antibiotic-resistance genes, integrons, and their gene cassette arrays. The results showed that the antibiotic-resistance genes blaTEM, tetC, sulI, aadA, floR, and qnrB were detected at high percentages, as were a number of other resistance genes. Class I integrons were present in 79.63% of the strains, and 10 out of 108 isolates carried class II integrons. Class III integrons were not detected. Three strains carried both class I and class II integrons, and 73.26% of the class I integron-positive isolates contained the qacEΔ1/sul1 gene. Fourteen types of integron cassette arrays were found among class I integron-positive isolates. A new array, dfrB4-catB3-blaOXA-10-aadA1, was discovered in this study. The gene cassette array dfrA12-orfF-aadA2 was the most widely distributed. In summary, 23 different gene cassettes encoding resistance to 8 classes of antibiotics were identified in the class I integrons, and the main cassettes contained genes encoding resistance to aminoglycosides (aad) and trimethoprim (dfr). All class II integron-positive strains had only a single gene cassette array, viz. dfrA1-catB2-sat2-aadA1. High levels of antimicrobial-resistance genes and integrons in eels and auqauculture ponds suggest that the overuse of antimicrobials should be strictly controlled and that the levels of bacterial antimicrobial-resistance genes in aquaculture should be monitored.

  14. Evolution by Pervasive Gene Fusion in Antibiotic Resistance and Antibiotic Synthesizing Genes

    Directory of Open Access Journals (Sweden)

    Orla Coleman

    2015-03-01

    Full Text Available Phylogenetic (tree-based approaches to understanding evolutionary history are unable to incorporate convergent evolutionary events where two genes merge into one. In this study, as exemplars of what can be achieved when a tree is not assumed a priori, we have analysed the evolutionary histories of polyketide synthase genes and antibiotic resistance genes and have shown that their history is replete with convergent events as well as divergent events. We demonstrate that the overall histories of these genes more closely resembles the remodelling that might be seen with the children’s toy Lego, than the standard model of the phylogenetic tree. This work demonstrates further that genes can act as public goods, available for re-use and incorporation into other genetic goods.

  15. DNA tagging of blast resistant gene(s in three Brazilian rice cultivars

    Directory of Open Access Journals (Sweden)

    S.S. Sandhu

    2003-12-01

    Full Text Available Rice blast is the most important fungal disease of rice and is caused by Pyricularia oryzae Sacc. (Telomorph Magnoporthe grisea Barr.. Seven randomly amplified polymorphic DNA (RAPD markers OPA5, OPG17, OPG18, OPG19, OPF9, OPF17 and OPF19 showed very clear polymorphism in resistant cultivar lines which differed from susceptible lines. By comparing different susceptible lines, nine DNA amplifications of seven primers (OPA5(1000, OPA5(1200, OPG17(700, OPG18(850, OPG19(500, OPG19(600, OPF9(600, OPF17(1200 and OPF19(600 were identified as dominant markers for the blast resistant gene in resistant cultivar lines. These loci facilitate the indirect scoring of blast resistant and blast susceptible genotypes. The codomine RAPDs markers will facilitate marker-assisted selection of the blast resistant gene in two blast resistant genotypes of rice (Labelle and Line 11 and will be useful in rice breeding programs.

  16. Correlation between intracellular accumulation of peptidoglycan precursors and streptomycin formation

    International Nuclear Information System (INIS)

    Nimi, Osamu; Kawashima, Hiroki; Sugiyama, Masanori; Nomi, Ryosaku

    1984-01-01

    When the mycelium of Streptomyces HUT 6037 was suspended in 0.5% NaCl solution containing 14 C-glucosamine, peptidoglycan precursors accumulated in the cells. While UDP-N-acetylglucosamine accumulated in the largest amount among the precursors, extracellularly added and intracellularly accumulated UDP-N-acetylglucosamine were not used to synthesize streptomycin and were probably used for peptidoglycan formation. On the other hand, correlation was recognized between accumulation of glucosamine-6-phosphate (GlcN-6P) and streptomycin formation. Addition of an inhibitor of peptidoglycan synthesis such as enduracidin, vancomycin or cycloserine to a mycelium-suspended culture changed the ratio of accumulated peptidoglycan precursors. When streptomycin formation was stimulated by addition of enduracidin or vancomycin, intracellular GlcN-6P remarkably increased and then decreased rapidly. On the contrary, when cycloserine was added to the culture, no increase of GlcN-6P was observed and streptomycin formation was not stimulated. These results suggest that an increase in the intracellular concentration of GlcN-6P is required for activation or induction of the system for utilizing GlcN-6P for streptomycin formation. (author)

  17. Occurrence of the mcr-1 Colistin Resistance Gene and other Clinically Relevant Antibiotic Resistance Genes in Microbial Populations at Different Municipal Wastewater Treatment Plants in Germany

    Directory of Open Access Journals (Sweden)

    Norman Hembach

    2017-07-01

    Full Text Available Seven wastewater treatment plants (WWTPs with different population equivalents and catchment areas were screened for the prevalence of the colistin resistance gene mcr-1 mediating resistance against last resort antibiotic polymyxin E. The abundance of the plasmid-associated mcr-1 gene in total microbial populations during water treatment processes was quantitatively analyzed by qPCR analyses. The presence of the colistin resistance gene was documented for all of the influent wastewater samples of the seven WWTPs. In some cases the mcr-1 resistance gene was also detected in effluent samples of the WWTPs after conventional treatment reaching the aquatic environment. In addition to the occurrence of mcr-1 gene, CTX-M-32, blaTEM, CTX-M, tetM, CMY-2, and ermB genes coding for clinically relevant antibiotic resistances were quantified in higher abundances in all WWTPs effluents. In parallel, the abundances of Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli were quantified via qPCR using specific taxonomic gene markers which were detected in all influent and effluent wastewaters in significant densities. Hence, opportunistic pathogens and clinically relevant antibiotic resistance genes in wastewaters of the analyzed WWTPs bear a risk of dissemination to the aquatic environment. Since many of the antibiotic resistance gene are associated with mobile genetic elements horizontal gene transfer during wastewater treatment can't be excluded.

  18. Identification and characterization of integron-mediated antibiotic resistance in the phytopathogen Xanthomonas oryzae pv. oryzae.

    Directory of Open Access Journals (Sweden)

    Ying Xu

    Full Text Available Four streptomycin-resistant isolates of Xanthomonas oryzae pv. oryzae (YNA7-1, YNA10-2, YNA11-2, and YNA12-2 were examined via PCR amplification for the presence of class 1, class 2, and class 3 integrons and aadA1 and aadA2 genes, which confer resistance to streptomycin and spectinomycin. The class 1 integrase gene intI1 and the aminoglycoside adenylyltransferase gene aadA1 were identified in all four resistant isolates but not in 25 sensitive isolates. PCR amplifications showed that 7790-bp, 7162-bp, 7790-bp, and 7240-bp resistance integrons with transposition gene modules (tni module in 3' conserved segments existed in YNA7-1, YNA10-2, YNA11-2, and YNA12-2, respectively. Subsequent analysis of sequences indicated that the integrons of YNA7-1 and YNA11-2 carried three gene cassettes in the order |aacA3|arr3|aadA1|. The integron of YNA10-2 carried only |arr3|aadA1| gene cassettes. The integron of YNA12-2 lacked a 550-bp sequence including part of intI1 but it still carried |aacA3|arr3|aadA1| gene cassettes. The analysis of inactive mutants and complementation tests confirmed that the aacA3 gene conferred resistance to tobramycin, kanamycin, gentamicin and netilmicin; the arr3 gene conferred resistance to rifampicin; and the aadA1 gene conferred resistance to streptomycin and spectinomycin. The resistance phenotypes of the four isolates corresponded with their resistance gene cassettes, except that YNA7-1 and YNA12-2 did not show rifampicin resistance. Sequence comparison revealed that no gene cassette array in GenBank was in the same order as in the integrons of the four resistant isolates in this study and the aadA1, which was identical in the four resistant isolates, showed 99% identity with aadA1 sequences in GenBank. The result of a stability test showed that the resistance phenotype, the aadA1 gene, and the intI1 gene were completely stable in YNA7-1 and YNA12-2 but unstable in YNA10-2 and YNA11-2. To our knowledge, this is the first

  19. Identification and Characterization of Integron-Mediated Antibiotic Resistance in the Phytopathogen Xanthomonas oryzae pv. oryzae

    Science.gov (United States)

    Zhou, Ming-guo

    2013-01-01

    Four streptomycin-resistant isolates of Xanthomonas oryzae pv. oryzae (YNA7-1, YNA10-2, YNA11-2, and YNA12-2) were examined via PCR amplification for the presence of class 1, class 2, and class 3 integrons and aadA1 and aadA2 genes, which confer resistance to streptomycin and spectinomycin. The class 1 integrase gene intI1 and the aminoglycoside adenylyltransferase gene aadA1 were identified in all four resistant isolates but not in 25 sensitive isolates. PCR amplifications showed that 7790-bp, 7162-bp, 7790-bp, and 7240-bp resistance integrons with transposition gene modules (tni module) in 3′ conserved segments existed in YNA7-1, YNA10-2, YNA11-2, and YNA12-2, respectively. Subsequent analysis of sequences indicated that the integrons of YNA7-1 and YNA11-2 carried three gene cassettes in the order |aacA3|arr3|aadA1|. The integron of YNA10-2 carried only |arr3|aadA1| gene cassettes. The integron of YNA12-2 lacked a 550-bp sequence including part of intI1 but it still carried |aacA3|arr3|aadA1| gene cassettes. The analysis of inactive mutants and complementation tests confirmed that the aacA3 gene conferred resistance to tobramycin, kanamycin, gentamicin and netilmicin; the arr3 gene conferred resistance to rifampicin; and the aadA1 gene conferred resistance to streptomycin and spectinomycin. The resistance phenotypes of the four isolates corresponded with their resistance gene cassettes, except that YNA7-1 and YNA12-2 did not show rifampicin resistance. Sequence comparison revealed that no gene cassette array in GenBank was in the same order as in the integrons of the four resistant isolates in this study and the aadA1, which was identical in the four resistant isolates, showed 99% identity with aadA1 sequences in GenBank. The result of a stability test showed that the resistance phenotype, the aadA1 gene, and the intI1 gene were completely stable in YNA7-1 and YNA12-2 but unstable in YNA10-2 and YNA11-2. To our knowledge, this is the first report of resistance

  20. Bacterial plasmid-mediated quinolone resistance genes in aquatic environments in China

    OpenAIRE

    Yan, Lei; Liu, Dan; Wang, Xin-Hua; Wang, Yunkun; Zhang, Bo; Wang, Mingyu; Xu, Hai

    2017-01-01

    Emerging antimicrobial resistance is a major threat to human?s health in the 21st century. Understanding and combating this issue requires a full and unbiased assessment of the current status on the prevalence of antimicrobial resistance genes and their correlation with each other and bacterial groups. In aquatic environments that are known reservoirs for antimicrobial resistance genes, we were able to reach this goal on plasmid-mediated quinolone resistance (PMQR) genes that lead to resistan...

  1. Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter.

    Science.gov (United States)

    Li, Lili; Heidemann Olsen, Rikke; Ye, Lei; Yan, He; Nie, Qing; Meng, Hecheng; Shi, Lei

    2016-04-01

    The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across species, genes conferring antimicrobial resistance were observed with the following frequencies: blaTEM, 40.7%; blaCMY-2, 15.2%; blaCTX-M, 11.5%; sul2, 27.2%; sul1, 14.4%; tet(A), 5.4%; tet(L), 5.4%; tet(M), 5.0%; tet(E), 3.7%; tet(C), 3.3%; tet(S), 2.5%; and tet(K), 0.8%. Various antimicrobial resistance genes were found in new carriers: blaTEM in Lactococcus garvieae, Myroides odoratimimus, Aeromonas hydrophila, Staphylococcus sciuri, Raoultella terrigena, Macrococcus caseolyticus, Acinetobacter ursingii, Sphingobacterium sp., and Oceanobacillus sp.; blaCMY-2 in Lactococcus lactis, Klebsiella oxytoca, Serratia marcescens, Acinetobacter baumannii, and Myroides phaeus; tet(L) in M. caseolyticus; sul1 in Vibrio cincinnatiensis; sul2 in Acinetobacter bereziniae, Acinetobacter johnsonii, and V. cincinnatiensis; and the class 1 integron and gene cassette aadA2 in V. cincinnatiensis. Approximately 6.6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor- encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance of aerobic bacteria from pork as reservoirs for antimicrobial resistance genes and mobile genetic elements that can readily be transferred intra- and interspecies.

  2. Diversity of Integron- and Culture-Associated Antibiotic Resistance Genes in Freshwater Floc

    OpenAIRE

    Drudge, Christopher N.; Elliott, Amy V. C.; Plach, Janina M.; Ejim, Linda J.; Wright, Gerard D.; Droppo, Ian G.; Warren, Lesley A.

    2012-01-01

    Clinically important antibiotic resistance genes were detected in culturable bacteria and class 1 integron gene cassettes recovered from suspended floc, a significant aquatic repository for microorganisms and trace elements, across freshwater systems variably impacted by anthropogenic activities. Antibiotic resistance gene cassettes in floc total community DNA differed appreciably in number and type from genes detected in bacteria cultured from floc. The number of floc antibiotic resistance g...

  3. Molecular study on some antibiotic resistant genes in Salmonella spp. isolates

    Science.gov (United States)

    Nabi, Ari Q.

    2017-09-01

    Studying the genes related with antimicrobial resistance in Salmonella spp. is a crucial step toward a correct and faster treatment of infections caused by the pathogen. In this work Integron mediated antibiotic resistant gene IntI1 (Class I Integrase IntI1) and some plasmid mediated antibiotic resistance genes (Qnr) were scanned among the isolated non-Typhoid Salmonellae strains with known resistance to some important antimicrobial drugs using Sybr Green real time PCR. The aim of the study was to correlate the multiple antibiotics and antimicrobial resistance of Salmonella spp. with the presence of integrase (IntI1) gene and plasmid mediated quinolone resistant genes. Results revealed the presence of Class I Integrase gene in 76% of the isolates with confirmed multiple antibiotic resistances. Moreover, about 32% of the multiple antibiotic resistant serotypes showed a positive R-PCR for plasmid mediated qnrA gene encoding for nalidixic acid and ciprofloxacin resistance. No positive results could be revealed form R-PCRs targeting qnrB or qnrS. In light of these results we can conclude that the presence of at least one of the qnr genes and/or the presence of Integrase Class I gene were responsible for the multiple antibiotic resistance to for nalidixic acid and ciprofloxacin from the studied Salmonella spp. and further studies required to identify the genes related with multiple antibiotic resistance of the pathogen.

  4. Polyamines modulate streptomycin-induced mistranslation in Escherichia coli.

    Science.gov (United States)

    Nastri, H G; Fastame, I G; Algranati, I D

    1993-12-14

    The effects of intracellular levels of polyamines on both the in vivo inhibition of protein synthesis and the decrease of translation accuracy induced by streptomycin have been studied in polyamine-auxotrophic strains of Escherichia coli infected with the MS2 bacteriophage. The amount of viral coat protein formed was strongly reduced upon addition of increasing concentrations of streptomycin to polyamine-supplemented bacteria. In contrast, the antibiotic almost did not inhibit coat protein synthesis in polyamine-starved cells. The increase of mistranslation frequency elicited by streptomycin was only observed in bacteria grown with putrescine. In these cells several coat protein-satellites were detected after two-dimensional gel electrophoresis. These proteins, more basic than the normal MS2 coat protein, contain multiple substitutions of lysine for asparagine.

  5. 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.

  6. A review of the influence of treatment strategies on antibiotic resistant bacteria and antibiotic resistance genes.

    Science.gov (United States)

    Sharma, Virender K; Johnson, Natalie; Cizmas, Leslie; McDonald, Thomas J; Kim, Hyunook

    2016-05-01

    Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) in the aquatic environment have become an emerging contaminant issue, which has implications for human and ecological health. This review begins with an introduction to the occurrence of ARB and ARG in different environmental systems such as natural environments and drinking water resources. For example, ARG or ARB with resistance to ciprofloxacin, sulfamethoxazole, trimethoprim, quinolone, vancomycin, or tetracycline (e.g., tet(A), tet(B), tet(C), tet(G), tet(O), tet(M), tet(W), sul I, and sul II) have been detected in the environment. The development of resistance may be intrinsic, may be acquired through spontaneous mutations (de novo), or may occur due to horizontal gene transfer from donor bacteria, phages, or free DNA to recipient bacteria. An overview is also provided of the current knowledge regarding inactivation of ARB and ARG, and the mechanism of the effects of different disinfection processes in water and wastewater (chlorination, UV irradiation, Fenton reaction, ozonation, and photocatalytic oxidation). The effects of constructed wetlands and nanotechnology on ARB and ARG are also summarized. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Analysis of differentially expressed genes related to resistance in spinosad- and neonicotinoid-resistant Musca domestica L. (Diptera: Muscidae) strains

    DEFF Research Database (Denmark)

    Castberg, Dorte Heidi Højland; Kristensen, Michael

    2017-01-01

    interesting in terms of neonicotinoid resistance, while cyp4d9 was overexpressed in 791spin compared to spinosad-susceptible strains. GSTs, ESTs and UGTs were mostly overexpressed, but not to the same degree as P450s. We present a comprehensive and comparative picture of gene expression in three housefly......Background The housefly is a global pest that has developed resistance to most insecticides applied against it. Resistance of the spinosad-resistant strain 791spin and the neonicotinoid-resistant 766b strain is believed to be due to metabolism. We investigate differentially expressed genes...... strains differing significantly in their response to insecticides. High differential expression of P450s and genes coding for cuticle protein indicates a combination of factors involved in metabolic neonicotinoid and spinosad resistance. Conclusion Resistance in these strains is apparently not linked...

  8. 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 < 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 = 0.130-0.486, 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

  9. 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

  10. 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...

  11. Sulfonamide-Resistant Bacteria and Their Resistance Genes in Soils Fertilized with Manures from Jiangsu Province, Southeastern China

    Science.gov (United States)

    Jiao, Shaojun; Zhang, Jun; Ye, Boping; Gao, Shixiang

    2014-01-01

    Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of antibiotic resistance genes (ARGs) increasingly in the soil. The frequency of sulfonamide resistance genes was sul1 > sul2 > sul3 in pig-manured soil DNA and sul2 > sul1 > sul3 in chicken-manured soil DNA. Further analysis suggested that the frequency distribution of the sul genes in the genomic DNA and plasmids of the SR isolates from manured soil was sul2 > sul1 > sul3 overall (panimal type and sampling time can influence the prevalence and distribution pattern of sulfonamide resistance genes. The present study also indicated that Bacillus, Pseudomonas and Shigella were the most prevalent sul-positive genera in the soil, suggesting a potential human health risk. The above results could be important in the evaluation of antibiotic-resistant bacteria and genes from manure as sources of agricultural soil pollution; the results also demonstrate the necessity and urgency of the regulation and supervision of veterinary antibiotics in China. PMID:25405870

  12. Novel Genes Related to Ceftriaxone Resistance Found among Ceftriaxone-Resistant Neisseria gonorrhoeae Strains Selected In Vitro.

    Science.gov (United States)

    Gong, Zijian; Lai, Wei; Liu, Min; Hua, Zhengshuang; Sun, Yayin; Xu, Qingfang; Xia, Yue; Zhao, Yue; Xie, Xiaoyuan

    2016-04-01

    The emergence of ceftriaxone-resistantNeisseria gonorrhoeaeis currently a global public health concern. However, the mechanism of ceftriaxone resistance is not yet fully understood. To investigate the potential genes related to ceftriaxone resistance inNeisseria gonorrhoeae, we subcultured six gonococcal strains with increasing concentrations of ceftriaxone and isolated the strains that became resistant. After analyzing several frequently reported genes involved in ceftriaxone resistance, we found only a single mutation inpenA(A501V). However, differential analysis of the genomes and transcriptomes between pre- and postselection strains revealed many other mutated genes as well as up- and downregulated genes. Transformation of the mutatedpenAgene into nonresistant strains increased the MIC between 2.0- and 5.3-fold, and transformation of mutatedftsXincreased the MIC between 3.3- and 13.3-fold. Genes encoding the ABC transporters FarB, Tfq, Hfq, and ExbB were overexpressed, whilepilM,pilN, andpilQwere downregulated. Furthermore, the resistant strain developed cross-resistance to penicillin and cefuroxime, had an increased biochemical metabolic rate, and presented fitness defects such as prolonged growth time and downregulated PilMNQ. In conclusion, antimicrobial pressure could result in the emergence of ceftriaxone resistance, and the evolution of resistance ofNeisseria gonorrhoeaeto ceftriaxone is a complicated process at both the pretranscriptional and posttranscriptional levels, involving several resistance mechanisms of increased efflux and decreased entry. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  13. Genetics and mapping of a new leaf rust resistance gene in Triticum ...

    Indian Academy of Sciences (India)

    AMIT KUMAR SINGH

    Selection G12 showed resistance at both seedling and adult plant stages. Genetic analysis in F1, F2 and F2:3 families at the seedling stage revealed that leaf rust resistance in Selection G12 is conditioned by a single incompletely dominant gene. The leaf rust resistance gene was mapped to chromosome 3BL with SSR ...

  14. Characterization of resistance genes to Cladosporium fulvum on the short arm of chromosome 1 of tomato

    NARCIS (Netherlands)

    Haanstra, J.

    2000-01-01

    Plant breeders generally use qualitative resistance that is associated with a hypersensitive reaction (HR) to obtain cultivars that are resistant to pathogens and pests. The genetics of this resistance is based on the gene-for-gene relationship, which involves the product of a plant

  15. Distribution and quantification of antibiotic resistance genes and bacteria across agricultural and non-agricultural metagenomes

    Science.gov (United States)

    There is concern that antibiotic resistance can potentially be transferred from animals to humans through the food chain. The relationship between specific antibiotic resistant bacteria and the genes they carry remains to be described and few details are known about how antibiotic resistance genes i...

  16. Rapid identification of rice blast resistance gene by specific length amplified fragment sequencing

    Directory of Open Access Journals (Sweden)

    Shen Chen

    2016-05-01

    Full Text Available Excavation of resistance genes is one of the most effective and environment-friendly measures to control the devastating rice disease caused by Magnaporthe oryzae. Many resistance genes have been mapped and characterized in the last century. Nevertheless, only a few of the total resistance genes could be really applied in the rice breeding program. Huazhan (HZ is a new native rice restorer line developed in China and widely used in hybrid rice in recent years. HZ and its crossed combinations usually show a broad spectrum of resistance against rice blast in different rice ecosystems in China. Dissection of the genetic background of HZ is very useful for its further application. In this study, a combined method based on bulked segregation analysis (BSA and specific length amplified fragment sequencing (SLAF-seq was used to identify blast resistance gene(s in HZ. A total of 56,187 SLAFs labels were captured and 9051 polymorphic SLAFs markers were analysed and procured in this study. One trait associated with candidate resistance genes region on chromosome 12 overlapping 10.2–17.6 Mb has been identified, in which 10 NBS-LRR (nucleotide-binding site-leucine-rich repeat coding genes were used as resistance gene candidates. Our result indicated that SLAF-seq with BSA is a rapid and effective method for initial identification of blast resistance genes. The identification of resistance gene in HZ will improve its molecular breeding and resistance variety application.

  17. Genes for resistance to wheat powdery mildew in derivatives of Triticum Timopheevi and T. Carthlicum

    DEFF Research Database (Denmark)

    Jørgensen, Jørgen Helms; Jensen, C. J.

    1972-01-01

    and/or Ml designated genes; a temporary designation, Ml f ,is proposed for this gene. Gene Ml f is closely associated with a gene conditioning resistance to the stem rust fungus (Puccinia graminis f. sp. tritici), probably gene Sr9c. The winter wheat line TP 229 derived from Triticum carthlicum has...

  18. Pharmacokinetics of streptomycin sulfate in Staphylococcus aureus-infected Clarias gariepinus (Burchell 1822

    Directory of Open Access Journals (Sweden)

    O.O. Oladele

    2014-01-01

    Possible systemic therapeutic value is suggested, depending on increased distribution of streptomycin and levels of streptomycin in kidneys of diseased fish at corresponding times being higher than in sera.

  19. Salmonella enterica in imported and domestic day-old turkey poults in Egypt: repertoire of virulence genes and their antimicrobial resistance profiles.

    Science.gov (United States)

    Osman, K M; Marouf, S H; Erfan, A M; AlAtfeehy, N

    2014-12-01

    Globalisation and international trade facilitate the rapid spread and transmission of foodborne pathogens. This study was designed to determine the serovars, distribution of virulence genes (invA, avrA, ssaQ, mgtC, siiD, sopB, gipA, sodC1, sopE1, spvC, bcfC) and antibiotic resistance profiles in salmonellae recovered from imported and domestic day-old turkey poults in Egypt. The prevalence of salmonellae in the imported poults was 4% (6/150): S. Enteritidis was the most frequent isolate (1.3%; 2/150), followed by Typhimurium, Virchow, Larochelle and a non-typeable strain, each with 0.7% (1/150) prevalence. The prevalence of salmonellae in the domestic poults was < 2% (2/150) and serotyping indicated a prevalence of 1.3% (1/150) for both Typhimurium and Altona. In polymerase chain reaction screening, the genes invA, sopB and bcfC were detected in all the Enteritidis, Typhimurium, Virchow, Larochelle, Altona and non-typeable isolates (100%); the gene gipA was absent from all isolates. Carriage of invA, sopB and bcfC among the Enteritidis, Typhimurium, Virchow, Larochelle, Altona and non-typeable isolates was associated with a core pattern of resistance to three antibiotics: streptomycin, nalidixic acid and chloramphenicol. The detection of S. Enteritidis, Typhimurium, Virchow, Larochelle, and Altona in turkey poults has important implications because these serovars are a significant cause of foodborne illness and enteric fever in humans.

  20. Dispersion of the vancomycin resistance genes vanA and vanC of Enterococcus isolated from Nile tilapia on retail sale: A public health hazard

    Directory of Open Access Journals (Sweden)

    Kamelia Mahmoud Osman

    2016-08-01

    Full Text Available Although normally regarded harmless commensals, enterococci may cause a range of different infections in humans, including urinary tract infections, sepsis, and endocarditis. The acquisition of vancomycin resistance by enterococci (VRE has seriously affected the treatment and infection control of these organisms. VRE are frequently resistant to all antibiotics that are effective treatment for vancomycin-susceptible enterococci, which leaves clinicians treating VRE infections with limited therapeutic options. With VRE emerging as a global threat to public health, we aimed to isolate, identify enterococci species from tilapia and their resistance to van-mediated glycopeptide (vanA and vanC as well as the presence of enterococcal surface protein (esp using conventional and molecular methods. The cultural, biochemical (Vitek 2 system and PCR results revealed eight Enterococcus isolates from the 80 fish samples (10% to be further identified as E. faecalis (6/8, 75% and E gallinarum (2/8, 25%. Intraperitoneal injection of healthy Nile tilapia with the eight Enterococcus isolates caused significant morbidity (70% within 3 days and 100% mortality at 6 days post injection with general signs of septicemia. All of the eight Enterococcus isolates were found to be resistant to tetracycline. The 6/6 E. faecalis isolates were susceptible for penicillin, nitrofurantoin, gentamicin, and streptomycin. On the other hand 5/6 were susceptible for ampicillin, vancomycin, chloramphenicol and ciprofloxacin. The two isolates of E. gallinarum were sensitive to rifampicin and ciprofloxacin and resistant to vancomycin, chloramphenicol and erythromycin. Molecular characterization proved that they all presented the prototypic vanC element. On the whole, one of the two vancomycin resistance gene was present in 3/8 of the enterococci isolates, while the esp virulence gene was present in 1/8 of the enterococci isolates. The results in this study emphasise the potential role

  1. Mapping and Cloning of Late Blight Resistance Genes from Solanum venturii Using an Interspecific Candidate Gene Approach

    NARCIS (Netherlands)

    Pel, M.; Foster, S.J.; Park, T.H.; Rietman, H.; Arkel, van G.; Jones, J.D.G.; Eck, van H.J.; Jacobsen, E.; Visser, R.G.F.; Vossen, van der E.A.G.

    2009-01-01

    Late blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases of potato. Resistance (R) genes from the wild species Solanum demissum have been used by breeders to generate late-blight-resistant cultivars but resistance was soon overcome by the pathogen. A more

  2. 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

    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...... study showed a frequent occurrence of resistance to fluoroquinolones, tetracycline and macrolides among staphylococci isolated from broilers in Denmark, whereas the occurrence of resistance to other antimicrobial agents remains low. Similar genes, encoding resistance to erythromycin, tetracycline...

  3. Clusters of Antibiotic Resistance Genes Enriched Together Stay Together in Swine Agriculture.

    Science.gov (United States)

    Johnson, Timothy A; Stedtfeld, Robert D; Wang, Qiong; Cole, James R; Hashsham, Syed A; Looft, Torey; Zhu, Yong-Guan; Tiedje, James M

    2016-04-12

    Antibiotic resistance is a worldwide health risk, but the influence of animal agriculture on the genetic context and enrichment of individual antibiotic resistance alleles remains unclear. Using quantitative PCR followed by amplicon sequencing, we quantified and sequenced 44 genes related to antibiotic resistance, mobile genetic elements, and bacterial phylogeny in microbiomes from U.S. laboratory swine and from swine farms from three Chinese regions. We identified highly abundant resistance clusters: groups of resistance and mobile genetic element alleles that cooccur. For example, the abundance of genes conferring resistance to six classes of antibiotics together with class 1 integrase and the abundance of IS6100-type transposons in three Chinese regions are directly correlated. These resistance cluster genes likely colocalize in microbial genomes in the farms. Resistance cluster alleles were dramatically enriched (up to 1 to 10% as abundant as 16S rRNA) and indicate that multidrug-resistant bacteria are likely the norm rather than an exception in these communities. This enrichment largely occurred independently of phylogenetic composition; thus, resistance clusters are likely present in many bacterial taxa. Furthermore, resistance clusters contain resistance genes that confer resistance to antibiotics independently of their particular use on the farms. Selection for these clusters is likely due to the use of only a subset of the broad range of chemicals to which the clusters confer resistance. The scale of animal agriculture and its wastes, the enrichment and horizontal gene transfer potential of the clusters, and the vicinity of large human populations suggest that managing this resistance reservoir is important for minimizing human risk. Agricultural antibiotic use results in clusters of cooccurring resistance genes that together confer resistance to multiple antibiotics. The use of a single antibiotic could select for an entire suite of resistance genes if

  4. Host range of antibiotic resistance genes in wastewater treatment plant influent and effluent.

    Science.gov (United States)

    Hultman, Jenni; Tamminen, Manu; Pärnänen, Katariina; Cairns, Johannes; Karkman, Antti; Virta, Marko

    2018-04-01

    Wastewater treatment plants (WWTPs) collect wastewater from various sources for a multi-step treatment process. By mixing a large variety of bacteria and promoting their proximity, WWTPs constitute potential hotspots for the emergence of antibiotic resistant bacteria. Concerns have been expressed regarding the potential of WWTPs to spread antibiotic resistance genes (ARGs) from environmental reservoirs to human pathogens. We utilized epicPCR (Emulsion, Paired Isolation and Concatenation PCR) to detect the bacterial hosts of ARGs in two WWTPs. We identified the host distribution of four resistance-associated genes (tetM, int1, qacEΔ1and blaOXA-58) in influent and effluent. The bacterial hosts of these resistance genes varied between the WWTP influent and effluent, with a generally decreasing host range in the effluent. Through 16S rRNA gene sequencing, it was determined that the resistance gene carrying bacteria include both abundant and rare taxa. Our results suggest that the studied WWTPs mostly succeed in decreasing the host range of the resistance genes during the treatment process. Still, there were instances where effluent contained resistance genes in bacterial groups not carrying these genes in the influent. By permitting exhaustive profiling of resistance-associated gene hosts in WWTP bacterial communities, the application of epicPCR provides a new level of precision to our resistance gene risk estimates.

  5. Analytical Performance of Multiplexed Screening Test for 10 Antibiotic Resistance Genes from Perianal Swab Samples.

    Science.gov (United States)

    Walker, G Terrance; Rockweiler, Tony J; Kersey, Rossio K; Frye, Kelly L; Mitchner, Susan R; Toal, Douglas R; Quan, Julia

    2016-02-01

    Multiantibiotic-resistant bacteria pose a threat to patients and place an economic burden on health care systems. Carbapenem-resistant bacilli and extended-spectrum β-lactamase (ESBL) producers drive the need to screen infected and colonized patients for patient management and infection control. We describe a multiplex microfluidic PCR test for perianal swab samples (Acuitas(®) MDRO Gene Test, OpGen) that detects the vancomycin-resistance gene vanA plus hundreds of gene subtypes from the carbapenemase and ESBL families Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-β-lactamase (NDM), Verona integron-mediated metallo-β-lactamase (VIM), imipenemase metallo-β-lactamase (IMP), OXA-23, OXA-48, OXA-51, CTX-M-1, and CTX-M-2, regardless of the bacterial species harboring the antibiotic resistance. Analytical test sensitivity per perianal swab is 11-250 CFU of bacteria harboring the antibiotic resistance genes. Test throughput is 182 samples per test run (1820 antibiotic resistance gene family results). We demonstrate reproducible test performance and 100% gene specificity for 265 clinical bacterial organisms harboring a variety of antibiotic resistance genes. The Acuitas MDRO Gene Test is a sensitive, specific, and high-throughput test to screen colonized patients and diagnose infections for several antibiotic resistance genes directly from perianal swab samples, regardless of the bacterial species harboring the resistance genes. © 2015 American Association for Clinical Chemistry.

  6. Pyramiding of three bacterial blight resistance genes for broad-spectrum resistance in deepwater rice variety, Jalmagna.

    Science.gov (United States)

    Pradhan, Sharat Kumar; Nayak, Deepak Kumar; Mohanty, Soumya; Behera, Lambodar; Barik, Saumya Ranjan; Pandit, Elssa; Lenka, Srikanta; Anandan, Annamalai

    2015-12-01

    Jalmagna is a popular deepwater rice variety with fa