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At least 829 records · Page 46Linked to original sources
PubMed2002

Identification of the Staphylococcus aureus etd pathogenicity island which encodes a novel exfoliative toxin, ETD, and EDIN-B.

We identified a novel pathogenicity island in Staphylococcus aureus which contains open reading frames (ORFs) similar to the exfoliative toxin (ET) gene, glutamyl endopeptidase gene, and edin-B gene in tandem and the phage resistance gene, flanked by hsdM, hsdS (restriction and modification system), and IS256. The protein encoded by the ET-like gene showed 40, 59, and 68% amino acid sequence identities with exfoliative toxin A (ETA), exfoliative toxin B (ETB), and Staphylococcus hyicus ETB (ShETB), respectively. When injected into neonatal mice, the recombinant protein derived from the ET-like gene induced exfoliation of the skin with loss of cell-to-cell adhesion in the upper part of the epidermis as observed in histological examinations, just as was found in neonatal mice injected with ETA or ETB. Western blot analysis indicated that the recombinant protein is serologically distinct from ETA and ETB. Therefore, the product encoded by this new ORF is a new ET member produced by S. aureus and is termed ETD. ETD did not induce blisters in 1-day-old chickens. In the skins of mice injected with ETD, cell surface staining of desmoglein 1 (Dsg1), a cadherin type cell-to-cell adhesion molecule in desmosomes, was abolished without affecting that of desmoglein 3 (Dsg3). Furthermore, in vitro incubation of the recombinant extracellular domains of Dsg1 and Dsg3 with the recombinant protein demonstrated that both mouse and human Dsg1, but not Dsg3, were directly cleaved in a dose-dependent manner. These results demonstrate that ETD and ETA induce blister formation by identical pathophysiological mechanisms. Clinical strains positive for edin-B were suggested to be clonally associated, and all edin-B-positive strains tested were positive for etd. Among 18 etd-positive strains, 12 produced ETD extracellularly. Interestingly, these strains are mainly isolated from other sources of infections and not from patients with bullous impetigo or staphylococcal scalded-skin syndrome. This strongly suggests that ETD might play a pathogenic role in a broader spectrum of bacterial infections than previously considered.

Amino Acid Sequence↗
PubMed1983

Rapid method for detection, identification, and susceptibility testing of enteric pathogens.

Three hundred and seven colonies believed to be enteric pathogens were selected from primary plates of MacConkey, xylose desoxycholate, or salmonella-shigella agar for inoculation to lactose-sucrose broth, urea-41 motility medium, modified Andrade glucose broth with inverted Durham tube, pregrowth broth, triple sugar iron agar, lysine iron agar (LIA), and Christensen urea agar. The rapid screen consisted of interpreting the lactose-sucrose, urea-41 motility, and modified Andrade glucose broth gas reactions after 4 to 6 h at 35 degrees C. These rapid screening biochemicals plus LIA were incubated for 24 h if further interpretation was required. Reference biochemicals (triple sugar iron, LIA, and Christensen urea agars) were interpreted at 24 h. Of 307 isolates, 49 (16%) were reported as negative for enteric pathogens after 4 to 6 h because their biochemical profiles were not compatible with those for enteric pathogens. A total of 87 (28.3%) isolates produced biochemical profiles at 4 to 6 h that were presumptive for enteric pathogens. The 87 presumptive pathogens were inoculated into the AutoMicrobic system Gram-Negative General Susceptibility Card and the AutoMicrobic system Enterobacteriaceae-Plus Biochemical Card (AMS-EBC+) after 4 to 6 h of growth in pregrowth broth. Of these isolates, 63 were confirmed to be enteric pathogens, of which 61 (96.8%) were correctly identified by the AMS-EBC+. One isolate was identified as Shigella dysenteriae by AMS-EBC+ but confirmed as Shigella flexneri biotype 6 by a reference laboratory. The other isolate was identified as Arizona hinshawii by AMS-EBC+ but was confirmed as Salmonella enteritidis. Of the 307 isolates, 166 (54.1%) required further interpretation of the rapid screening biochemicals plus LIA at 24 h; 5 of these were detected as enteric pathogens. The same 68 enteric pathogens were detected by both the rapid method and the reference method. The results from the general susceptibility card agreed with agar diffusion results at 99.2%. One Salmonella enteritidis and four Shigella spp. showed minor discrepancies with tetracycline. No very major or major discrepancies were observed.

Bacteriological Techniques↗
PubMed2001

Identification, classification, and phylogeny of the pathogenic species Exophiala jeanselmei and related species by mitochondrial cytochrome b gene analysis.

We analyzed a 402-bp sequence of the mitochondrial cytochrome b gene of 34 strains of Exophiala jeanselmei and 16 strains representing 12 related species. The strains of E. jeanselmei were classified into 20 DNA types and 17 amino acid types. The differences between these strains were found in 1 to 60 nucleotides and 1 to 17 amino acids. On the basis of the identities and similarities of nucleotide and amino acid sequences, some strains were reidentified: i.e., two strains of E. jeanselmei var. hetermorpha and one strain of E. castellanii as E. dermatitidis (including the type strain), three strains of E. jeanselmei as E. jeanselmei var. lecanii-corni (including the type strain), three strains of E. jeanselmei as E. bergeri (including the type strain), seven strains of E. jeanselmei as E. pisciphila (including the type strain), seven strains of E. jeanselmei as E. jeanselmei var. jeanselmei (including the type strain), one strain of E. jeanselmei as Fonsecaea pedrosoi (including the type strain), and one strain of E. jeanselmei as E. spinifera (including the type strain). Some E. jeanselmei strains showed distinct nucleotide and amino acid sequences. The amino-acid-based UPGMA (unweighted pair group method with the arithmetic mean) tree exhibited nearly the same topology as those of the DNA-based trees obtained by neighbor joining, maximum parsimony, and maximum likelihood methods.

Cytochrome b Group↗
PubMed1980

Avian retroviruses that cause carcinoma and leukemia: identification of nucleotide sequences associated with pathogenicity.

Avian myelocytomatosis virus (MC29V) is a retrovirus that transforms both fibroblasts and macrophages in culture and induces myelocytomatosis, carcinomas, and sarcomas in birds. Previous work identified a sequence of about 1,500 nucleotides (here denoted onc(MCV)) that apparently derived from a normal cellular sequence and that may encode the oncogenic capacity of MC29V. In an effort to further implicate onc(MCV) in tumorigenesis, we used molecular hybridization to examine the distribution of nucleotide sequences related to onc(MCV) among the genomes of various avian retroviruses. In addition, we characterized further the genetic composition of the remainder of the MC29V genome. Our work exploited the availability of radioactive DNAs (cDNA's) complementary to onc(MCV) (cDNA(MCV)) or to specific portions of the genome of avian sarcoma virus (ASV). We showed that genomic RNAs of avian erythroblastosis virus (AEV) and avian myeloblastosis virus (AMV) could not hybridize appreciably with cDNA(MCV). By contrast, cDNA(MCV) hybridized extensively (about 75%) and with essentially complete fidelity to the genome of Mill Hill 2 virus (MH2V), whose pathogenicity is very similar to that of MC29V, but different from that of AEV or AMV. Hybridization with the ASV cDNA's demonstrated that the MC29V genome includes about half of the ASV envelope protein gene and that the remainder of the MC29V genome is closely related to nucleotide sequences that are shared among the genomes of many avian leukosis and sarcoma viruses. We conclude that onc(MCV) probably specifies the unique set of pathogenicities displayed by MC29V and MH2V, whereas the oncogenic potentials of AEV and AMV are presumably encoded by a distinct nucleotide sequence unrelated to onc(MCV). The genomes of ASV, MC29V, and other avian oncoviruses thus share a set of common sequences, but apparently owe their various oncogenic potentials to unrelated transforming genes.

Alpharetrovirus↗
PubMed1997

Identification of a replication-competent pathogenic human immunodeficiency virus type 1 with a duplication in the TCF-1alpha region but lacking NF-kappaB binding sites.

Multiple human immunodeficiency virus type 1 (HIV-1) sequences with deletions of NF-kappaB binding sites at both the 5' and 3' long terminal repeats (LTRs) were identified in serial samples collected from an infected individual. The effect of this deletion on the level of transcription was studied by transient transfection of an LTR-driven luciferase reporter gene and by infection with a full-length recombinant HIV-1 containing a luciferase reporter (HIVHXBluc). Detectable levels of gene expression were found in both systems, in the presence or absence of the viral transactivator Tat. Interestingly, a duplication of a putative TCF-1alpha motif was found in place of the NF-kappaB elements in these viruses. Higher transcriptional activity was observed with HXBLTR (NF-kappaB intact) than with the patient's LTR (NF-kappaB deleted), suggesting that the NF-kappaB binding sites may promote optimal levels of viral gene transcription. The ability of these viruses with NF-kappaB deleted to replicate and cause substantial decline in CD4 cell counts demonstrates that the NF-kappaB binding sites are not absolutely required for viral replication or pathogenicity in vivo. These results are consistent with the notion that the HIV-1 LTR possesses functional redundancy which allows it to interact with multiple transcription factors, thereby ensuring viral replication in a variety of cell types.

Base Sequence↗
PubMed2024

Identification of a novel EYA4 likely pathogenic variant in a Chinese family with postlingual non-syndromic hearing loss and analysis of molecular epidemiology of EYA4 variants.

BACKGROUND: EYA4 variants are responsible for DFNA10 deafness. Due to its insidious onset and slow progression, hearing loss in autosomal dominant non-syndromic hearing loss (ADNSHL) is usually challenging to detect early in clinical settings, with limited intervention options. Genetic testing can aid in early detection of hearing loss, enabling timely intervention to reduce disability rates and improve the quality of life. METHODS: In this study, we report the case of a Chinese family with postlingual and progressive hearing loss that was passed down for four generations. Whole-exome sequencing (WES) was performed on DNA samples from the proband. Candidate variants identified in the proband and family members were confirmed via Sanger sequencing. In silico prediction tools and co-segregation analyses were used to assess the pathogenicity of identified variants. A literature review of known EYA4 variants was performed, analysing variant frequency, distribution characteristics across different populations, and genotype-phenotype correlations. RESULTS: We identified a novel EYA4 variant, c.1745_1748del (p.Glu582ValfsTer6), in a Chinese family with ADNSHL, and co-segregation with the family's phenotype was confirmed. The audiometry showed mid-to-high frequency downsloping hearing loss. To date, 52 pathogenic variants of EYA4 have been reported, with majority identified in Asian populations. Most observed are the missense and frameshift variants. CONCLUSIONS: A novel variant of EYA4 was identified in a Chinese family with postlingual hearing loss, contributing to the expanding spectrum of EYA4 variants. The audiological features of EYA4 variants are highly heterogeneous and often challenging to detect early in clinical settings. Our findings highlight the significance of genetic testing in patients presenting with postlingual hearing loss.

Humans↗
PubMed2006

[Isolation, identification and phylogenetic analysis of a pathogenic bacterium in channel catfish].

A pathogenic bacterium (CCF00024) was isolated from the kidney and liver of the diseased channel catfish with acute epidemic disease. Artificial infection proved that the bacterium was the pathogen of the disease. Its morphological, physiological, biochemical characteristics and 16S rDNA sequence analysis were studied. The isolated strain is an aerobic, non-fermentative bacterium. The bacteria are gram negative, rods, with polar multi-flagella; Oxidase-negative, methyl-red-negative, lysine decarboxylase-positive, DNAase-positive, urease-positive, lipase-positive and protease-positive. The bacteria can't utilize most of sugars with production of acid, except maltose and mannose. A phylogenetic tree was constructed by comparing the 16S rDNA sequence of the isolated strain (GenBank accession number AY970826) with other relative bacteria species in the RDP and GenBank databases. In the phylogenetic tree CCF00024, Stenotrophomonas maltophilia 13637T, Stenotrophomonas maltophilia MG958T, and Stenotrophomonas maltophilia M5-1 constitute a branch. The similarity value between strain CCF00024 and those 5 strains Stenotrophomonas maltophilia are 99.4%-99.6%. According to morphological, physiological, biochemical characteristics and phylogenetic analysis, the isolated strain (CCF00024) is identified as Stenotrophomonas maltophilia.

Animals↗
PubMed1977

Enteric pathogens: use of flow diagrams for identification.

A protocol is presented for the cultural processing of stool specimens. Flow diagrams were developed which allow all stool cultures to be processed in a consistent and efficient manner. Criteria have been established to indicate when definitive identification and antimicrobial susceptibility testing are required. A review of the food-poisoning syndrome and infective gastrointestinal disease due to bacterial agents is included.

Aeromonas↗
PubMed1983

Identification of stocks of non-pathogenic "Entamoeba histolytica".

The isoenzyme mobilities, on thin layer starch gel electrophoresis, of stocks of Entamoeba histolytica have been shown to relate to pathogenicity in the host. The ability of some zymodemes of this organism to produce extra-intestinal lesions is also coupled with a capacity to resist lysis by human serum. The results of isoenzyme characterization particularly related to serum lysis is discussed.

Entamoeba histolytica↗
PubMed1993

DNA-based identification and epidemiologic typing of bacterial pathogens.

Genotypic, or DNA-based, methods have become increasingly applicable for infectious disease diagnosis and epidemiologic analysis. The ability to assess the pathogen's genotype directly bypasses requirements for cultivation and may diminish diagnostic delays with fastidious organisms. Genotypic typing methods have enhanced epidemiologic studies by providing techniques with greater discriminatory ability and smaller proportions of nontypeable samples. Hence, these methods enable rigorous studies to be performed regarding the nature of disease outbreaks. Phenotypic, or conventional, methods will remain important in diagnostic microbiology, especially with organisms that are relatively easy to culture. However, genotypic methods may become increasingly prominent in clinical microbiology laboratories, particularly with respect to diagnosis of fastidious pathogens, because of their relative speed, versatility, and lack of cultivation requirements.

Bacteria↗
PubMed1997

Towards the routine application of nucleic acid technology for avian disease diagnosis.

The use of nucleic acid technology (polymerase chain reaction, probing, restriction fragment analysis and nucleotide sequencing) in the study of avian diseases has largely been confined to fundamental analysis and retrospective studies. More recently these approaches have been applied to diagnosis and what one might call real-time epidemiological studies on chickens and turkeys. At the heart of these approaches is the identification and characterisation of pathogens based on their genetic material, RNA or DNA. Among the objectives has been the detection of pathogens quickly combined with the simultaneous identification of serotype, subtype or genotype. Nucleic acid sequencing also gives a degree of characterisation unmatched by other approaches. In this paper we describe the use of nucleic acid technology for the diagnosis and epidemiology of infectious bronchitis virus, turkey rhinotracheitis virus (avian pneumovirus) and Newcastle disease virus.

Animals↗
PubMed1978

[Isolation and identification of Clamydia psittaci as the pathogen in enzootic abortion of sheep in eastern Slovakia].

Abortions in ewes occurred on a large scale in three localities in eastern Slovakia. Antibodies to the group-type ornithosis antigen were detected in titres of 1 : 128 to 1 : 2048 in the aborting ewes in the mentioned localities. Suspensions were prepared from the four samples of material, obtained either from the placentae and afterbirths of the aborting ewes or from the tissues of the aborted foetuses. Seven-day old yolk sacs of chicken embryos were infected with these suspensions. Four strains of Chlamydia psittaci were isolated and designated EPO-A2-uterus, EPO-B1 aborted foetus-lung, EPO-B2-aborted foetus-lung, EPO-B3-aborted foetus-spleen. Differential diagnosis eliminated some bacteria, toxoplasma, and parainfluenza-3 virus as possible agents responsible for the abortions.

Abortion, Veterinary↗
PubMed1998

Comparison of RapID yeast plus system with API 20C system for identification of common, new, and emerging yeast pathogens.

The ability to identify yeast isolates by the new enzymatic RapID Yeast Plus System was compared to the ability to identify yeast isolates by the API 20C system. A total of 447 yeast isolates representing Blastoschizomyces capitatus, 17 Candida spp., 5 Cryptococcus spp., Geotrichum spp., 2 Hanseniaspora spp., Hansenula anomala, Hansenula wingei, 3 Rhodotorula spp., Saccharomyces cerevisiae, Sporobolomyces salmonicolor, Trichosporon beigelii, and 2 Prototheca spp. were evaluated. Also, five quality control strains (Candida spp. and Cryptococcus laurentii) with well-documented reactivities by the RapID Yeast Plus System were used. Each isolate was evaluated by both methods with a 48-h culture grown at 30 degrees C on Sabouraud dextrose agar (Emmons modification) by following the recommendations of the manufacturers. The RapID Yeast Plus System enzymatic reactions were read after 4 h of incubation, and the API 20C carbohydrate assimilation identification profiles were obtained after 72 h of incubation. There was good (95.7%) agreement between the identifications obtained by the two methods with the eight common Candida spp. and with Cryptococcus neoformans. The agreement was lower when the emerging Candida spp. and other yeast-like pathogens were tested (79.1 and 75.2%, respectively). These preliminary data suggest the potential utility of the RapID Yeast Plus System for use in the clinical laboratory for the rapid identification of common yeast pathogens as well as certain new and emerging species.

Yeasts↗
PubMed2006

Application of DNA microarray technology for detection, identification, and characterization of food-borne pathogens.

DNA microarrays represent the latest advance in molecular technology. In combination with bioinformatics, they provide unparalleled opportunities for simultaneous detection of thousands of genes or target DNA sequences and offer tremendous potential for studying food-borne microorganisms. This review provides an up-to-date look at the application of DNA microarray technology to detect food-borne pathogenic bacteria, viruses, and parasites. In addition, it covers the advantages of using microarray technology to further characterize microorganisms by providing information for specific identification of isolates, to understand the pathogenesis based on the presence of virulence genes, and to indicate how new pathogenic strains evolved epidemiologically and phylogenetically.

Animals↗
PubMed1995

An idiotype D23-bearing polyspecific, murine anti-DNA monoclonal antibody forms glomerular immune deposits. Pathogenic role of natural autoantibodies?

Identification of the immunochemical and structural properties of pathogenic anti-DNA antibodies is a major goal for understanding their origins and the mechanisms whereby they induce tissue lesions. Herein, we report on the production of an IgG2a,k anti-DNA monoclonal antibody (4B1), derived from a 12-month-old (NZB x NZW)F1 lupus mouse, able to form glomerular immune deposits. mAb 4B1 is a polyspecific antibody able to bind to ssDNA, actin, tubulin, cardiolipin and to laminin as shown by solid phase ELISAs. Indirect immunofluorescence labeling of HEp-2 cells gave a cytoplasmic staining pattern similar to that obtained with anti-cytoskeleton antibodies. Western blot analysis demonstrated that mAb 4B1 bore idiotype D23, previously shown to be characteristic of natural antibodies derived from normal mice. After injecting the 4B1-secreting hybridoma intraperitoneally into normal (NZW x BALB/c)F1 mice, glomerular immune deposits were observed along the capillary wall. These deposits contained mainly IgM, IgG2a and mAb 4B1, as demonstrated by direct immunofluorescence using a biotinylated-rat anti-4B1 idiotype mAb and kidney eluate analysis. Nucleotide sequence analysis of the VH and VL genes showed that mAb 4B1 is encoded by VH Q52, DSP2.9 and JH2 genes with minimal mutations and by VK8 very similar to the canonic D23 light chain, and JK1 germline genes. No arginine residues were observed in the VH CDR and both chains lacked N-segment addition. Thus, no structural characteristics deduced from the primary structure of mAb 4B1 could explain its pathogenic potential. However, the immunochemical and structural properties suggest that autoantibodies closely related to natural autoantibodies may be pathogenic.

Amino Acid Sequence↗