Molecular characterization of trimethoprim resistance inShigella sonneiin Sicily

SUMMARYDuring the 3-year period 1985–7, all strains ofShigella sonneiisolated in Catania, Sicily, showed a high level of resistance to trimethoprim (Tp) which was invariably associated with resistance to other antibiotics.Plasmid analysis showed 18 different electropherotypes: 35 of 37 strains harboured a plasmid of 70 Megadaltons (MDa), and 29 of 37 strains a plasmid of 130 MDa.Restriction endonuclease fingerprinting of purified 70 MDa plasmid DNA from different strains demonstrated that these plasmids were similar but not identical.In some strains with transferable Tp resistance, DNA hybridization analysis demonstrated the presence of genes coding for the production of dihydrofolate reductase (DHFR) type V. In contrast, there was no detectable hybridization with DNA probes specific for genes coding for DHFR types I, II and IV. This is the first report of the DHFR type V gene outside Sri Lanka.

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Host Range of Streptomycete Strains Causing Common Scab

Plant Disease ◽

10.1094/pdis.1997.81.8.901 ◽

1997 ◽

Vol 81 (8) ◽

pp. 901-904 ◽

Cited By ~ 51

Author(s):

Claudia Goyer ◽

Carole Beaulieu

Keyword(s):

Host Range ◽

Daucus Carota ◽

Dna Hybridization ◽

Common Scab ◽

Genetic Cluster ◽

Dna Relatedness ◽

Physiological Characterization ◽

Genetic Clusters ◽

High Level

Ten Streptomyces isolates from common scab lesions on carrots (Daucus carota) were characterized. Morphological and physiological characterization of the carrot isolates established that they were closely related to S. scabies. DNA-DNA hybridization studies were carried out between DNA from the carrot isolates and DNA from two potato strains belonging to the two genetic clusters of S. scabies. Most of the carrot isolates exhibited a high level of DNA relatedness (average of 90%) to strain EF-54, which belongs to genetic cluster 1 of S. scabies. Three carrot isolates could not be included in either S. scabies genetic cluster 1 or 2. The pathogenicity of six S. scabies isolates from potato or carrot, two isolates of S. caviscabies, and one isolate of S. acidiscabies was determined on potato, carrot, radish, beet, turnip, and parsnip. All S. scabies isolates were pathogenic on carrot and radish, but pathogenicity on beet, parsnip, turnip, and potato was variable. Even though S. acidiscabies and S. caviscabies until now have been isolated only from potato, we demonstrated that isolates of these species also could infect other crops, such as radish, carrot, parsnip, and turnip.

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Two small linear plasmids of Streptomyces jumonjinensis

Canadian Journal of Microbiology ◽

10.1139/m97-090 ◽

1997 ◽

Vol 43 (7) ◽

pp. 633-638

Author(s):

Donald J. Netolitzky ◽

Susan E. Jensen ◽

Kenneth L. Roy

Keyword(s):

Plasmid Dna ◽

Dna Hybridization ◽

Southern Hybridization ◽

Dna Homology ◽

Linear Plasmids ◽

Streptomyces Spp ◽

Copy Numbers ◽

Significant Homology ◽

Lactam Antibiotic

In a survey of plasmids in a variety of β-lactam antibiotic producing Streptomyces spp., two small linear plasmids (pSJL1 and pSJL2) of approximately 12 and 17.5 kb were detected within Streptomyces jumonjinensis NRRL 5741, in addition to the previously reported giant linear plasmids pSJL3 and pSJL4. Characterization of these plasmids by Southern hybridization indicated that no significant homology exists between the S. jumonjinensis plasmids and plasmids detected in other β-lactam antibiotic producing Streptomyces spp. Single and double restriction endonuclease digestions were performed to generate maps of the two plasmids. The plasmids pSJL1 and pSJL2 have copy numbers of 21–27 and 15–20, respectively.Key words: Streptomyces, linear plasmid, DNA hybridization, DNA homology.

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The distribution of the DHFR genes in trimethoprim-resistant urinary tract isolates from Taiwan

Epidemiology and Infection ◽

10.1017/s0950268800050445 ◽

1992 ◽

Vol 109 (3) ◽

pp. 453-462 ◽

Cited By ~ 4

Author(s):

Lin-Li Chang ◽

Shui-Feng Chang ◽

Teh-Yuan Chow ◽

Wen-Jeng Wu ◽

Jong-Chou Chang

Keyword(s):

Escherichia Coli ◽

Dihydrofolate Reductase ◽

Type I ◽

Type Ii ◽

Colony Hybridization ◽

Resistant Strains ◽

High Level ◽

Type V ◽

Urinary Isolates ◽

Level Resistance

SUMMARYBetween July 1987 and June 1989, 1054 urinary isolates of enterobacteria from Kaohsiung, Taiwan were studied for their trimethoprim resistance. Trimethoprim resistance was defined as MIC greater than 4 μg/ml and high-level resistance by MIC greater than 1000 μg/ml. The incidence of trimethoprim resistance increased from 33·6% in 1987 to 42·1% in 1989. Among the resistant strains studied, 90% were resistant to high levels of trimethoprim. An increase in the proportion of resistant strains (33·9–46·3%) exhibiting high-level non-transferable trimethoprim resistance was noted. The distribution of the dihydrofolate reductase (DHFR) genes by colony hybridization in 374 trimethoprim-resistant isolates revealed the presence of type I and type V DHFR genes in most of these isolates (45·4% and 10·4% respectively). Type I was predominant inEscherichia coliwhereas type V was frequently seen inEnterobacterspp. None showed homology with the type II and type III DHFR probe DNA. In addition, transposon Tn7 was present in 7·8% of 374 trimethoprim-resistant enterobacteria.

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Cloning and Characterization of a Gene Encoding the Major Surface Protein of the Bacterial EndosymbiontWolbachia pipientis

Journal of Bacteriology ◽

10.1128/jb.180.9.2373-2378.1998 ◽

1998 ◽

Vol 180 (9) ◽

pp. 2373-2378 ◽

Cited By ~ 403

Author(s):

Henk R. Braig ◽

Weiguo Zhou ◽

Stephen L. Dobson ◽

Scott L. O’Neill

Keyword(s):

Molecular Mechanisms ◽

Cytoplasmic Incompatibility ◽

Surface Protein ◽

Gene Encoding ◽

Developmental Abnormalities ◽

Intracellular Symbiont ◽

Different Strains ◽

Major Surface ◽

High Level

ABSTRACT The maternally inherited intracellular symbiont Wolbachia pipientis is well known for inducing a variety of reproductive abnormalities in the diverse arthropod hosts it infects. It has been implicated in causing cytoplasmic incompatibility, parthenogenesis, and the feminization of genetic males in different hosts. The molecular mechanisms by which this fastidious intracellular bacterium causes these reproductive and developmental abnormalities have not yet been determined. In this paper, we report on (i) the purification of one of the most abundantly expressed Wolbachia proteins from infected Drosophila eggs and (ii) the subsequent cloning and characterization of the gene (wsp) that encodes it. The functionality of the wsp promoter region was also successfully tested in Escherichia coli. Comparison of sequences of this gene from different strains of Wolbachiarevealed a high level of variability. This sequence variation correlated with the ability of certain Wolbachia strains to induce or rescue the cytoplasmic incompatibility phenotype in infected insects. As such, this gene will be a very useful tool forWolbachia strain typing and phylogenetic analysis, as well as understanding the molecular basis of the interaction ofWolbachia with its host.

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Characterization of the bla KPC-2 and bla KPC-3 genes and the novel bla KPC-15 gene in Klebsiella pneumoniae

Journal of Medical Microbiology ◽

10.1099/jmm.0.073841-0 ◽

2014 ◽

Vol 63 (7) ◽

pp. 981-987 ◽

Cited By ~ 7

Author(s):

Dongguo Wang ◽

Wei Hou ◽

Jiayu Chen ◽

Yonghua Mou ◽

Linjun Yang ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Gene Mapping ◽

Southern Blot ◽

Blot Hybridization ◽

Carbapenem Resistance ◽

Southern Blot Hybridization ◽

The Novel ◽

Plasmid Analysis ◽

High Level

Three Klebsiella pneumoniae isolates exhibiting high-level resistance to carbapenem were analysed by PCR, PFGE, gene mapping, plasmid conjugation and Southern blot hybridization using a bla KPC probe. In addition to the frequently reported bla KPC-2 and bla KPC-3 genes, a novel bla KPC-15 gene was identified in one of the isolates. The results of plasmid analysis and Southern blot hybridization revealed that the three bla KPC genes were located on transferable plasmids exhibiting three different patterns. The patterns A, B and C were observed in the genetic makeup of each individual plasmid, and all three structures contained ISKpn6-like and ISKpn8 transposons. The results of the gene mapping and hybridization experiments performed with the bla KPC probe demonstrated that the plasmids harboured the three genes at approximately the 85.0, 54.0 and 73.0 kb positions. The study concluded that carbapenem resistance in the three isolates was primarily due to the production of carbapenem-hydrolysing β-lactamase.

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Further taxonomic characterization of the genus Bdellovibrio

Canadian Journal of Microbiology ◽

10.1139/m78-222 ◽

1978 ◽

Vol 24 (11) ◽

pp. 1387-1394 ◽

Cited By ~ 18

Author(s):

Francisco Torrella ◽

Richard Guerrero ◽

Ramon J. Seidler

Keyword(s):

Host Range ◽

Dna Hybridization ◽

Deoxyribonucleic Acid ◽

Experimental Conditions ◽

C Genome ◽

Time Differential ◽

High Level ◽

First Time ◽

Taxonomic Characterization

Cultures of Bdellovibrio isolated from different geographic locations have been studied in terms of deoxyribonucleic acid analysis (% G + C, genome size, and DNA hybridization), cytochrome spectrum, and host range. Isolates of the genus exhibit a broad range of % G + C ranging from 37 to 51% and the genome sizes extend from 1300 × 106 to 1700 × 106 daltons. DNA hybridization continues to reveal a high level of genetic heterogeneity. Bdellovibrio 3294 exhibits 32% relative reassociation to Bdellovibrio W, 37% to Bdellovibrio stolpii Uki2, and an undetectible level to Bdellovibrio starrii A3.12. Bdellovibrio W is 23% related to B. starrii A3.12 and 28.5%to B. stolpii Uki2. For the first time differential absorption techniques have revealed peaks of cytochrome b. The analysis of the cytochrome spectrum seems to be limited as a taxonomic tool since most of the recent isolates studied share a common cytochrome spectrum. Host-range studies have been found to be dependent on the experimental conditions, and with the exception of one isolate (B. starrii A3.12) the taxonomic significance of such techniques must be taken with caution.

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Localization and Characterization of MupA Gene in High and Low-Level Mupirocin Resistant Methicillin Resistant Staphylococcus Aureus

10.51429/ejmm29322 ◽

2020 ◽

Vol 29 (3) ◽

pp. 171-177

Author(s):

Marwa S. Mostaf ◽

Alaa R. Awad

Keyword(s):

Staphylococcus Aureus ◽

Plasmid Dna ◽

Methicillin Resistant Staphylococcus Aureus ◽

Gene Location ◽

Chromosomal Dna ◽

Methicillin Resistant ◽

Low Level ◽

Mupirocin Resistance ◽

High Level

Background: Two types of mupirocin resistance among methicillin resistant Staphylococcus aureus (MRSA) have been reported; low-level mupirocin resistance (LL-MR), and high-level mupirocin resistance (HL-MR). The mupA gene is typically located on mobile genetic elements which facilitate the resistance dissemination. Objective: The aim of this work was to identify the mupA gene location, as well as the restriction fragment length polymorphism (RFLP) patterns in high and low-level mupirocin resistant MRSA. Methodology: This study was conducted on 100 MRSA isolates; seven of them were mupirocin resistant. The E test was used to identify high and low level mupirocin resistance. Amplification of mupA gene in total and plasmid DNA was performed. We also detected the spacer region (trsLM–IS257-like–mupA) in the 7 isolates by PCR then we investigated its RFLP patterns. Results: Four MR MRSA isolates had low level resistance, their MupA gene was located on chromosomal DNA, whereas, three isolates showed high level MR, their MupA gene was located on plasmid DNA. Four types of different RFLP patterns of the spacer region were identified; type-1 included two LL-MR isolates, each of type-2 and 3 included both HL-MR and LL-MR isolates, and type-4 included one HL-MR isolate. Conclusions: Staphylococcus aureus mupA gene responsible for LL-MR is located on the chromosome while that responsible for HL-MR is plasmid-mediated. The spacer region variations appear to occur in both chromosomal and plasmid-located mupA gene regardless the type of mupirocin resistance.

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