Decreased Clinical Severity of Strangles in Weanlings Associated with Restricted Seroconversion to Optimized Streptococcus equi ssp equi Assays.

BACKGROUND: Streptococcus equi ssp. equi causes characteristic clinical signs that are most severe in young horses, including fever, purulent nasal discharge, and lymph node abscessation in the head region. HYPOTHESIS/OBJECTIVES: Clinical, serologic, and microbiologic factors related to unexpectedly mild disease severity in a natural outbreak of strangles in immunologically naïve weanlings were investigated. ANIMALS: One-hundred and twelve warmblood weanlings. METHODS: Prospective longitudinal observational study of a natural outbreak of strangles. The entire cohort was examined at the peak of the outbreak by deep nasal swabs for culture and quantitative PCR (qPCR) for the presence of S. equi and clinically and serologically in a sequential manner by an optimized ELISA from the index case throughout the outbreak until resolution. Descriptive statistics were calculated and comparisons made using a nondirectional Wilcoxon signed-rank test. RESULTS: Outbreak morbidity was 53%, with 9 of 14 horses culture positive and 26 of 53 horses qPCR positive for S. equi lacking clinical signs characteristic of strangles. By resolution, 91 of 112 had seroconverted to Antigen A by ELISA but seroconversion to antigen C (part of the SeM protein) was minimal. Sequencing of the isolates detected no alterations in the SeM protein, but identified a 61 bp deletion in the gene SEQ_0402. CONCLUSIONS AND CLINICAL IMPORTANCE: Absence of clinical signs alone in naïve horses may be an insufficient criterion to release horses from strangles quarantine measures. Restricted seroconversion to antigen C may have been associated with decreased clinical severity. The role of a minor gene deletion in SEQ_0402 in the virulence of S. equi warrants further investigation.

Streptococcus equi subspecies equi in horses in Israel: seroprevalence and strain types.

The purpose of this cross-sectional study was to determine the seroprevalence of Streptococcus equi in Israel, to monitor seropositive horses over time and to identify archived strains that were recovered from Israeli horses. A serological survey of 200 healthy horses on 20 farms throughout Israel was performed to detect recent exposure to S equi antigens A and C via indirect ELISA. Seroprevalence was 9.5 per cent (19/200) and positive horses were found in 30 per cent (6/20) of the farms. Sixteen horses that returned a positive serology result were retested three and six months later. Most (12/16) positive horses remained positive, which suggests the presence of animals with persistent infection. Molecular characterisation of S equi strains by sequencing of the SeM gene of 16 archived isolates of S equi that were recovered from clinical cases of strangles between 2008 and 2012 identified two strains: SeM-2 and SeM-28.

Prevalence of Streptococcus dysgalactiae subsp. equisimilis and S. equi subsp. zooepidemicus in a sample of healthy dogs, cats and horses.

AIMS: To estimate the prevalence of ß-haemolytic Lancefield group C streptococci in healthy dogs, cats and horses; to determine if frequent contact with horses was associated with isolation of these species from dogs and cats; and to characterise recovered S. equi subsp. zooepidemicus isolates by multilocus sequence typing. METHODS: Oropharyngeal swabs were collected from 197 dogs and 72 cats, and nasopharyngeal swabs from 93 horses. Sampling was carried out at the Massey University Veterinary Teaching Hospital, on sheep and beef farms or on premises where horses were present. All animals were healthy and were categorised as Urban dogs and cats (minimal contact with horses or farm livestock), Farm dogs (minimal contact with horses) and Stable dogs and cats (frequent contact with horses). Swabs were cultured for ß-haemolytic Streptococcus spp. and Lancefield group C streptococcal subspecies were confirmed by phenotypic and molecular techniques. RESULTS: Of the 197 dogs sampled, 21 (10.7 (95% CI= 4.0-25.4)%) tested positive for S. dysgalactiae subsp. equisimilis and 4 (2.0 (95% CI=0.7-5.5)%) tested positive for S. equi subsp. zooepidemicus. All these isolates, except for one S. dysgalactiae subsp. equisimilis isolate in an Urban dog, were from Stable dogs. S. dysgalactiae subsp. equisimilis was isolated from one Stable cat. Of the 93 horses, 22 (23.7 (95% CI=12.3-40.6)%) and 6 (6.5 (95% CI=2.8-14.1)%) had confirmed S. dysgalactiae subsp. equisimilis and S. equi subsp. zooepidemicus isolation respectively. Isolation of S. dysgalactiae subsp. equisimilis from dogs was associated with frequent contact with horses (OR=9.8 (95% CI=2.6-72.8)). Three different multilocus sequence type profiles of S. equi subsp. zooepidemicus that have not been previously reported in dogs were recovered. CONCLUSIONS AND CLINICAL RELEVANCE: Subclinical infection or colonisation by S. equi subsp. zooepidemicus and S. dysgalactiae subsp. equisimilis occurs in dogs and further research on inter-species transmission and the pathogenic potential of these Lancefield group C streptococci is needed. Complete speciation of ß-haemolytic streptococci should be recommended in clinical cases and the possible exposure to horses and their environment should be considered in epidemiological investigations.

Prevalence and disease associations of superantigens szeF, szeN and szeP in the S. zooepidemicus population and possible functional redundancy of szeF.

Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) causes a variety of infections in a broad range of species. This study broadens prevalence data for three recently identified novel superantigens (szeF, szeN, and szeP) to define links between their presence and disease type. Screening of 437 strains across 190 sequence types (STs) revealed that 50% of strains contained superantigen genes. Results confirmed that the presence of S. zooepidemicus superantigen genes is significantly associated with non-Strangles lymph node abscessation in the horse (p-value = 0.003) and their absence is associated with uterine infection/abortion (p-value = 0.006). This study also investigated the lack of mitogenicity observed in szeF only. Results show that szeF is polymorphic, with 23 different alleles, and mutations altering the protein sequence. Gene expression differences are not responsible for lack of mitogenic activity in these strains. Taken together, these findings suggest that superantigens are important for S. zooepidemicus pathogenesis but SzeF probably has little involvement.

Molecular characterisation of 'strangles' outbreaks in the UK: the use of M-protein typing of Streptococcus equi ssp. equi.

REASONS FOR PERFORMING STUDY: Strangles is the most commonly diagnosed and important infectious disease of horses worldwide. Very little is known about the temporo-spatial and molecular epidemiology of strangles. The disease is not notifiable in the UK and there are few published data on the geographical locations of outbreaks. OBJECTIVE: To investigate whether typing of a surface protein (SeM) of Streptococcus equi ssp. equi (S. equi), the causative agent of strangles, is a useful epidemiological tool. METHODS: The variable region of the SeM gene was amplified from 145 isolates of S. equi by PCR and sequenced. Different SeM gene alleles were assigned based on the SeM database, grouped into phylogenetic clusters using split decomposition analysis and plotted against the submitting veterinary practices. RESULTS: In this study 21 S. equi SeM alleles were found, including 9 previously unidentified alleles and representing 4 phylogenetic groups. S. equi containing SeM alleles 9 and 7 were the most commonly isolated and there was a high number of low frequency alleles. The occurrence of an outbreak cluster in the north-west of the UK is also reported. CONCLUSIONS: Strangles outbreaks can be differentiated on the basis of their SeM allele sequences. The data provide further evidence of SeM mutation leading to the emergence of novel, but related SeM alleles that are geographically linked. Sequencing of the SeM gene is a useful tool for the elucidation of strangles epidemiology at a regional and a national level. POTENTIAL RELEVANCE: This technique may allow differentiation or linkage of strangles outbreaks and as such may be an effective tool for local as well as national and international disease surveillance.

Zoonotic transmission of Streptococcus equi subsp. zooepidemicus from a dog to a handler.

This is, to the best of our knowledge, the first case report to describe the apparent transmission of Streptococcus equi subsp. zooepidemicus from an infected dog to a handler who subsequently developed severe systemic infection. Characterization of the haemolytic streptococci isolated from both the patient and the dog, by phenotypic and molecular analysis, confirmed the canine and human isolates were identical.

Structure-based design, synthesis, and biological evaluation of indomethacin derivatives as cyclooxygenase-2 inhibiting nitric oxide donors.

Indomethacin, a nonselective cyclooxygenase (COX) inhibitor, was modified in three distinct regions in an attempt both to increase cyclooxygenase-2 (COX-2) selectivity and to enhance drug safety by covalent attachment of an organic nitrate moiety as a nitric oxide donor. A human whole-blood COX assay shows the modifications on the 3-acetic acid part of the indomethacin yielding an amide-nitrate derivative 32 and a sulfonamide-nitrate derivative 61 conferred COX-2 selectivity. Along with their respective des-nitrate analogs, for example, 31 and 62, the nitrates 32 and 61 were effective antiinflammatory agents in the rat air-pouch model. After oral dosing, though, only 32 increased nitrate and nitrite levels in rat plasma, indicating that its nitrate tether served as a nitric oxide donor in vivo. In a rat gastric injury model, examples 31 and 32 both show a 98% reduction in gastric lesion score compared to that of indomethacin. In addition, the nitrated derivative 32 inducing 85% fewer gastric lesions when coadministered with aspirin as compared to the combination of aspirin and valdecoxib.

T-cell-rich large-B-cell lymphomas contain non-activated CD8+ cytolytic T cells, show increased tumor cell apoptosis, and have lower Bcl-2 expression than diffuse large-B-cell lymphomas.

The factor(s) responsible for the reduced B cell number and increased T cell infiltrate in T-cell-rich large-B-cell lymphomas (TCRBCLs) have not been well characterized. We studied 18 TCRBCLs and 12 diffuse large-B-cell lymphomas (DLBCLs) to compare the 1) predominant T cell subpopulation(s), 2) expression of cytotoxic granule proteins (TIA-1 and granzyme B), 3) level of tumor cell apoptosis (Apoptag system, Oncor, Gaithersburg, MD), and 4) expression of Ki-67 (Mib-1) and apoptosis-related proteins (fas (CD95), bcl-2, and p53). T cells in TCRBCLs and DLBCLs were predominantly CD8+ T cells expressing alphabeta T-cell receptors and TIA-1 (16 of 18 TCRBCLs with >50% TIA-1+ small lymphocytes) but lacking granzyme B (16 of 18 TCRBCLs with <25% granzyme B+ small lymphocytes). Scattered apoptotic tumor cells (confirmed with CD20 co-labeling) were present in 15 of 18 TCRBCLs, with 14 of 15 cases having <10% apoptotic cells. No apoptotic cells were seen in 12 of 12 DLBCLs. In 16 of 16 immunoreactive TCRBCLs, <25% tumor cells were bcl-2+, whereas 6 of 12 DLBCLs had >50% bcl-2+ tumor cells. CD95 (fas) expression was also lower, with 3 of 18 (16.7%) TCRBCLs versus 4 of 12 (33%) DLBCLs having >25% CD95+ tumor cells. TCRBCLs and DLBCLs had similar levels of p53 and Ki-67 (Mib-1) expression. Thus, T cells in TCRBCLs are non-activated cytotoxic T lymphocytes (TIA-1+, granzyme B-). Tumor cell apoptosis (perhaps cytotoxic T cell mediated) may partly account for the decreased number of large (neoplastic) B cells in TCRBCLs, but other factors (ie, decreased bcl-2 expression) may also be needed.

ELT-1, a GATA-like transcription factor, is required for epidermal cell fates in Caenorhabditis elegans embryos.

Epidermal cells are generated during Caenorhabditis elegans embryogenesis by several distinct lineage patterns. These patterns are controlled by maternal genes that determine the identities of early embryonic blastomeres. We show that the embryonically expressed gene elt-1, which was shown previously to encode a GATA-like transcription factor, is required for the production of epidermal cells by each of these lineages. Depending on their lineage history, cells that become epidermal in wild-type embryos become either neurons or muscle cells in elt-1 mutant embryos. The ELT-1 protein is expressed in epidermal cells and in their precursors. We propose that elt-1 functions at an early step in the specification of epidermal cell fates.

Transcription frequency modulates the efficiency of an attenuator preceding the rpoBC RNA polymerase genes of Escherichia coli: possible autogenous control.

Expression of the rpoBC genes encoding the beta and beta' RNA polymerase subunits of Escherichia coli is autogenously regulated. Although previous studies have demonstrated a post-transcriptional feedback mechanism, complex transcriptional controls of rpoBC expression may also contribute. We show that an attenuator (rpoBa) separating the ribosomal protein (rpl) genes from the rpoBC genes in the rplKAJLrpoBC gene cluster is modulated in its efficiency in response to changes in the frequency of transcription initiated by promoters located upstream. A series of rplJLrpoBalacZ transcriptional fusions was constructed on lambda vectors in which transcription into the rpoBa attenuator was varied by using a variety of promoters with different strengths. beta-galactosidase assays performed on monolysogens of the recombinant phage show that with transcription increasing over a 40-fold range, readthrough of rpoBa decreases from 61% to 19%. In contrast, two other well-characterized terminators show nearly constant efficiencies over a similar range of transcription frequencies. Using a set of phage P22 ant promoter variants with single-nucleotide changes in the promoter consensus sequences also demonstrates that the modulation of rpoBa function appears to be unrelated to the phenomenon of 'factor-independent antitermination' reported by others. The implications for autogenous control of RNA polymerase synthesis are discussed.

In vivo analysis of overlapping transcription units in the rplKAJLrpoBC ribosomal protein-RNA polymerase gene cluster of Escherichia coli.

Transcription of the rplKAJLrpoBC ribosomal protein (rpl) RNA polymerase (rpo) gene cluster is governed by a complex set of signals. To dissect the transcription units active in vivo and to quantify the relative contribution of each, an extensive array of rplKAJLrpoB/lacZ gene fusions were constructed on lambda phage derivatives and introduced in single copy into the chromosomes of lac- cells. Measurements of beta-galactosidase production from fusions containing wild-type and/or mutagenized rplrpo DNA fragments permitted the establishment of high-resolution transcription profiles of the gene cluster. The results show that transcription initiated at the upstream rplKp promoter (located just before rplK) does not terminate before the rplJp promoter (located upstream from rplJ), but instead reads through into the distal genes. In addition, rplJp continues to function efficiently in the presence of readthrough transcription from rplKp. As a result the rplJL genes are transcribed at almost twice the frequency of the upstream rplKA genes. However, the transcription of rpoB, which is situated downstream from the previously identified attenuator (rpoBa), is only marginally increased (20%) when both promoters are present. This suggests that although both transcription units overlap, transcriptional termination at rpoBa is modulated in response to the frequency of initiation from both promoters.

The role of adherence in determining the site of infection by Corynebacterium diphtheriae.

Twenty-nine strains of Corynebacterium diphtheriae isolated from throats and 29 strains from skin lesions, the latter mainly from communities of low socio-economic status in tropics and cold climates, have been examined for the property of adherence to human buccal epithelial cells. All throat strains showed adherence. In contrast, strains from skin lesions were predominantly poor adherers. These results indicate that strains of C. diptheriae from throats must now be added to the important group of pathogens which possess the property of adherence to surface epithelial cells of mucous membranes, thus providing an essential first step in the process of colonizing their hosts. The possible role of this phenomenon of adherence to bucco-pharyngeal epithelial cells in the evolution of the host-parasite relationship of C. diphtheriae is discussed.

Transport of rubidium absorbed by the apex of the bean root.

Rubidium-86 was applied to the terminal 5.0 mm region of intact roots for a 6 hour period. The plants were then harvested after 0, 18, 24, 48, 72, or 96 hours additional growth in a rubidium-free continuously renewed nutrient solution. A substantial portion of the rubidium absorbed in a region of the root devoid of functional xylem tissue was ultimately transported to more basipetal regions.