scholarly journals The analysis of group в streptococcal clinical strains for the presence of the genes encoding for potential adherence factors and localized on the «pathogenicity islands»

2005 ◽  
Vol 54 (2) ◽  
pp. 50-55
Author(s):  
A. N. Suvorov ◽  
А. М. Savicheva ◽  
А. V. Glushanova ◽  
К. А. Oganyan ◽  
К. В. Grabovskaya ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Pathogenicity Islands ◽  
Clinical Strains ◽  
Invasive Diseases ◽  
Genes Encoding ◽  
Aggregation Factors

The collection of group В streptococcal clinical strains has been analyzed for the presence of genes encoding for putative adherence and aggregation factors. The presence of the genes designated as sspB1 and sspB2 were tested by PCR and DNA hybridization. The genes under study located in GBS genome on pathogenicity islands were found to be heterogeneous and could be associated with urological or invasive diseases. No significant correlation between the GBS serotype and sspB genes pattern have been discovered.

Distribution of Genes Encoding Four Pathogenicity Islands (VPaIs), T6SS, Biofilm, and Type I Pilus in Food and Clinical Strains ofVibrio parahaemolyticusin China

2010 ◽  
Vol 7 (6) ◽  
pp. 649-658 ◽  
Author(s):  
Guoxiang Chao ◽  
Xinan Jiao ◽  
Xiaohui Zhou ◽  
Fang Wang ◽  
Zhenquan Yang ◽  
...  
Keyword(s):  
Pathogenicity Islands ◽  
Type I ◽  
Clinical Strains ◽  
Genes Encoding

scholarly journals Characterization of lactococci isolated from homemade kefir

2007 ◽  
Vol 59 (1) ◽  
pp. 13-22 ◽  
Author(s):  
M. Kojic ◽  
Jelena Lozo ◽  
Jelena Begovic ◽  
B. Jovcic ◽  
Lj. Topisirovic
Keyword(s):  
Dna Hybridization ◽  
Antimicrobial Compounds ◽  
Plasmid Curing ◽  
Natural Isolate ◽  
Bacteriocin Activity ◽  
Proteinase Production ◽  
Genes Encoding ◽  
Traditionally Prepared ◽  
Cross Inhibition

Five bacteriocin-producing lactococci isolates from traditionally prepared kefir were determined as Lactococcus lactis subsp. lactis. The analyzed isolates showed different plasmid profiles and no cross inhibition between them was detected. Moreover, natural isolate BGKF26 was resistant to the antimicrobial activity of nisin producing strain NP45. Plasmid curing experiments revealed that the genes encoding bacteriocin and proteinase production are located on separate genetic elements, except in BGKF26. Production of the tested bacteriocins depends on the concentration of casitone or triptone in the medium. Higher concentrations of casitone or triptone induce bacteriocin activity. Our DNA-DNA hybridization analyses suggest that the analyzed antimicrobial compounds probably are lactococcin-like bacteriocins.

scholarly journals Multiple Mutations Lead to MexXY-OprM-Dependent Aminoglycoside Resistance in Clinical Strains of Pseudomonas aeruginosa

2013 ◽  
Vol 58 (1) ◽  
pp. 221-228 ◽  
Author(s):  
Sophie Guénard ◽  
Cédric Muller ◽  
Laura Monlezun ◽  
Philippe Benas ◽  
Isabelle Broutin ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Multidrug Resistant ◽  
Single Amino Acid ◽  
Leader Peptide ◽  
Dimerization Domain ◽  
Aminoglycoside Resistance ◽  
Content Type ◽  
Clinical Strains ◽  
Genes Encoding

ABSTRACTConstitutive overproduction of the pump MexXY-OprM is recognized as a major cause of resistance to aminoglycosides, fluoroquinolones, and zwitterionic cephalosporins inPseudomonas aeruginosa. In this study, 57 clonally unrelated strains recovered from non-cystic fibrosis patients were analyzed to characterize the mutations resulting in upregulation of themexXYoperon. Forty-four (77.2%) of the strains, classified asagrZmutants were found to harbor mutations inactivating the local repressor gene (mexZ) of themexXYoperon (n= 33; 57.9%) or introducing amino acid substitutions in its product, MexZ (n= 11; 19.3%). These sequence variations, which mapped in the dimerization domain, the DNA binding domain, or the rest of the MexZ structure, mostly affected amino acid positions conserved in TetR-like regulators. The 13 remaining MexXY-OprM strains (22.8%) contained intactmexZgenes encoding wild-type MexZ proteins. Eight (14.0%) of these isolates, classified asagrW1mutants, overexpressed the gene PA5471, which codes for the MexZ antirepressor AmrZ, with 5 strains exhibiting growth defects at 37°C and 44°C, consistent with mutations impairing ribosome activity. Interestingly, oneagrW1mutant appeared to harbor a 7-bp deletion in the coding sequence of the leader peptide, PA5471.1, involved in ribosome-dependent, translational attenuation of PA5471 expression. Finally, DNA sequencing and complementation experiments revealed that 5 (8.8%) strains, classified asagrW2mutants, harbored single amino acid variations in the sensor histidine kinase of ParRS, a two-component system known to positively controlmexXYexpression. Collectively, these results demonstrate that clinical strains ofP. aeruginosaexploit different regulatory circuitries to mutationally overproduce the MexXY-OprM pump and become multidrug resistant, which accounts for the high prevalence of MexXY-OprM mutants in the clinical setting.

scholarly journals Morphological and Genetic Diversity of Temperate Phages in Clostridium difficile

2007 ◽  
Vol 73 (22) ◽  
pp. 7358-7366 ◽  
Author(s):  
Louis-Charles Fortier ◽  
Sylvain Moineau
Keyword(s):  
Electron Microscopy ◽  
Genetic Diversity ◽  
Clostridium Difficile ◽  
Dna Hybridization ◽  
Southern Hybridization ◽  
The Other ◽  
Restriction Profile ◽  
Transmission Electron ◽  
The Family ◽  
Genes Encoding

ABSTRACT Eight temperate phages were characterized after mitomycin C induction of six Clostridium difficile isolates corresponding to six distinct PCR ribotypes. The hypervirulent C. difficile strain responsible for a multi-institutional outbreak (NAP1/027 or QCD-32g58) was among these prophage-containing strains. Observation of the crude lysates by transmission electron microscopy (TEM) revealed the presence of three phages with isometric capsids and long contractile tails (Myoviridae family), as well as five phages with long noncontractile tails (Siphoviridae family). TEM analyses also revealed the presence of a significant number of phage tail-like particles in all the lysates. Southern hybridization experiments with restricted prophage DNA showed that C. difficile phages belonging to the family Myoviridae are highly similar and most likely related to previously described prophages φC2, φC5, and φCD119. On the other hand, members of the Siphoviridae phage family are more genetically divergent, suggesting that they originated from distantly related ancestors. Our data thus suggest that there are at least three genetically distinct groups of temperate phages in C. difficile; one group is composed of highly related myophages, and the other two groups are composed of more genetically heterogeneous siphophages. Finally, no gene homologous to genes encoding C. difficile toxins or toxin regulators could be identified in the genomes of these phages using DNA hybridization. Interestingly, each unique phage restriction profile correlated with a specific C. difficile PCR ribotype.

Clinical strains of Acinetobacter classified by DNA-DNA hybridization

Apmis ◽  
1989 ◽  
Vol 97 (7-12) ◽  
pp. 595-605 ◽  
Author(s):  
INGELA TJERNBERG ◽  
JAN URSING
Keyword(s):  
Dna Hybridization ◽  
Clinical Strains

scholarly journals gyrA and gyrB Mutations Are Implicated in Cross-Resistance to Ciprofloxacin and Moxifloxacin in Clostridium difficile

2002 ◽  
Vol 46 (11) ◽  
pp. 3418-3421 ◽  
Author(s):  
Larbi Dridi ◽  
Jacques Tankovic ◽  
Béatrice Burghoffer ◽  
Frédéric Barbut ◽  
Jean-Claude Petit
Keyword(s):  
Amino Acid ◽  
Clostridium Difficile ◽  
Ethidium Bromide ◽  
Dna Hybridization ◽  
Pcr Amplification ◽  
Cross Resistance ◽  
Topoisomerase Iv ◽  
Clinical Strains ◽  
Resistant Strains ◽  
Arbitrarily Primed Pcr

ABSTRACT A total of 198 nonrepetitive clinical strains of Clostridium difficile isolated from different French hospitals in 1991 (n = 100) and 1997 (n = 98) were screened for decreased susceptibility to fluoroquinolones by plating onto Wilkins-Chalgren agar containing 16 μg of ciprofloxacin per ml. The frequency of decreased susceptibility was 7% (14 of 198) and was identical for the years 1991 and 1997. Serogroups C, H, D, A9, and K accounted for five, four, two, one, and one of the resistant strains, respectively, one strain being nontypeable. Arbitrarily primed PCR typing showed that all resistant strains had unique patterns except two serotype C strains, which could not be clearly distinguished. All isolates with decreased susceptibility carried a mutation either in gyrA (eight mutations, amino acid changes Asp71→Val in one, Thr82→Ile in six, and Ala118→Thr in one) or in gyrB (six mutations, amino acid changes Asp426→Asn in five and Arg447→Leu in one). These changes are similar to those already described in other species except for Asp71→Val, which is novel, and Ala118→Thr, which is exceptional. Attempts to detect the topoisomerase IV parC gene by PCR amplification with universal parC primers or DNA-DNA hybridization under low-stringency conditions were unsuccessful. The susceptibilities of all resistant strains to ciprofloxacin and ethidium bromide were not affected by the addition of reserpine at 20 μg/ml. In conclusion, decreased susceptibility to fluoroquinolones in C. difficile is rare in France and is associated with the occurrence of a gyrA or gyrB mutation.

Adhesins encoded by the gingipain genes of Porphyromonas gingivalis are responsible for co-aggregation with Prevotella intermedia

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1257-1264 ◽  
Author(s):  
Arihide Kamaguchi ◽  
Tohru Ohyama ◽  
Eiko Sakai ◽  
Reiko Nakamura ◽  
Toshihiro Watanabe ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Bacterial Species ◽  
Gel Filtration ◽  
Prevotella Intermedia ◽  
Bacterial Cells ◽  
Terminal Portion ◽  
Genes Encoding ◽  
Sepharose 4B ◽  
Genomic Dna Sequence ◽  
Aggregation Factors

Co-aggregation among bacterial cells caused by the adherence of one bacterial species to another is a potential colonization mechanism. Several putative aggregation factors for co-aggregation between Porphyromonas (Por.) gingivalis and Prevotella (Pre.) intermedia were partially purified from Por. gingivalis vesicles by gel filtration and affinity chromatography. Antisera against the aggregation factors were made. Analysis using these antisera revealed that 18 and 44 kDa proteins might be responsible for Por. gingivalis vesicle-mediated aggregation of Pre. intermedia. Using antiserum against the 18 kDa protein, the DNA region encoding it was cloned from Por. gingivalis genomic DNA. Sequence analysis revealed that the DNA region was located within the rgpA and kgp genes, encoding Arg-gingipain (Rgp) and Lys-gingipain (Kgp), respectively, and it encoded non-catalytic adhesin domain regions, namely a C-terminal portion of HGP15, the entire HGP17 sequence and an N-terminal portion of HGP27. A portion of the DNA sequence was also found in the haemagglutinin A (hagA) gene. A recombinant glutathione S-transferase (GST)–HGP17 fusion protein reacted to antiserum against the 18 kDa protein and Pre. intermedia cells could adhere to GST–HGP17-conjugated Sepharose 4B beads, indicating that the HGP17 domain protein is responsible for Por. gingivalis vesicle-mediated aggregation of Pre. intermedia.

Description and Genome Analysis of Microvirga Antarctica Sp. Nov., A Novel Pink-Pigmented Psychrotolerant Bacterium Isolated From Antarctic Soil

2021 ◽  
Author(s):  
Lin Zhu ◽  
Weiwei Ping ◽  
Siyue Zhang ◽  
Ya Chen ◽  
Ying Zhang ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Rrna Gene ◽  
Isolated Cells ◽  
Species Determination ◽  
Closely Related Species ◽  
Genomic Analyses ◽  
Genes Encoding ◽  
Psychrotolerant Bacterium ◽  
Ubiquinone 10 ◽  
Threshold Range

Abstract During the investigation of exploring potential psychrotolerant species from Antarctica soil, a novel pink-pigmented bacterium designated strain 3D7T was isolated. Cells of the isolate were observed to be rod-shaped (0.7–0.9×1.0–2.2 µm), Gram-stain negative and non-motile. It was able to grow at 4–32 ℃, pH 7.0–10.0 and in the presence of 0–3 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 3D7T belongs to the genus Microvirga and was most closely related to ‘Microvirga brassicacearum’ CDVBN77T (98.3 %), Microvirga subterranea DSM 14364T (96.8 %), Microvirga guangxiensis 25BT (96.5 %) and Microvirga aerophila DSM 21344T (96.5 %). The predominant quinone was ubiquinone 10 (Q-10), and the major fatty acids were summed feature 8 (C18:1ω7c and/or C18:1ω6c) and C19:0 cyclo ω8c. The predominant polar lipids were phosphatidylcholine and phosphatidylethanolamine. The genomic DNA G + C content of strain 3D7T was 63.5 mol%. Its genome sequence showed genes encoding phosphatases and lipases. Genetic machinery related to carbohydrate-active enzymes and secondary metabolites were also observed. The average nucleotide identity and digital DNA–DNA hybridization values based on whole genome sequences of strain 3D7T and its closely related species were below the threshold range for species determination. Phenotypic, chemotaxonomic, phylogenetic and genomic analyses suggested that strain 3D7T represents a novel species of the genus Microvirga, for which the name Microvirga antarctica sp. nov. is proposed. The type strain is 3D7T (= CGMCC 1.13821T = KCTC 72465T).

DNA Microarray-Based Genomic Characterization of the Pathotypes of Escherichia coli O26, O45, O103, O111, and O145 Isolated from Feces of Feedlot Cattle†

2019 ◽  
Vol 82 (3) ◽  
pp. 395-404 ◽  
Author(s):  
PRAGATHI B. SHRIDHAR ◽  
ISHA R. PATEL ◽  
JAYANTHI GANGIREDLA ◽  
LANCE W. NOLL ◽  
XIAORONG SHI ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Microarray ◽  
Virulence Genes ◽  
Feedlot Cattle ◽  
Clinical Strains ◽  
E Coli ◽  
Type Iii ◽  
Virulence Potential ◽  
Genes Encoding ◽  
Secretory System

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 serogroups, are responsible for more than 70% of human non-O157 STEC infections in North America. Cattle harbor non-O157 strains in the hindgut and shed them in the feces. The objective of this study was to use the U.S. Food and Drug Administration (FDA) E. coli identification (ECID) DNA microarray to identify the serotype, assess the virulence potential of each, and determine the phylogenetic relationships among five of the six non-O157 E. coli serogroups isolated from feedlot cattle feces. Forty-four strains of STEC, enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), or putative nonpathotype E. coli (NPEC) of cattle origin and five human clinical strains of EHEC were assayed with the FDA-ECID DNA microarray. The cattle strains harbored diverse flagellar genes. The bovine and human strains belonging to serogroups O26, O45, and O103 carried stx1 only, O111 carried both stx1 and stx2, and O145 carried either stx1 or stx2. The strains were also positive for various subtypes of intimin and other adhesins (IrgA homologue adhesin, long polar fimbriae, mannose-specific adhesin, and curli). Both human and cattle strains were positive for LEE-encoded type III secretory system genes and non–LEE-encoded effector genes. SplitsTree4, a program used to determine the phylogenetic relationship among the strains, revealed that the strains within each serogroup clustered according to their pathotype. In addition to genes encoding Shiga toxins, bovine non-O157 E. coli strains possessed other major virulence genes, including those for adhesins, type III secretory system proteins, and plasmid-borne virulence genes, similar to human clinical strains. Because virulence factors encoded by these genes are involved in the pathogenesis of various pathotypes of E. coli, the bovine non-O157 strains could cause human illness. The FDA-ECID DNA microarray assay rapidly provided a profile of the virulence genes for assessment of the virulence potential of each strain.

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