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Viability studies on actinomycetes.

Eighty-nine Actinomycetes strains were tested for their viability, morphological and physiological characteristics after being kept under paraffin oil overlay and distilled water for a period between 10-30 years. Most of the studied strains belong to the "Lorenzo De Montemayor" collection. Almost all the recovered strains were 28-30 years old and had never been subcultured since the paraffin oil was overlaid. 71.4% of viable Streptomycetes strains had been kept on Sabouraud-dextrose agar and 28.6% were kept on Negroni and Bonfiglioli-medium. Streptomyces violaceusruber produced its characteristic pigment even after 28 years under these conditions. All of the recovered strains were tested for their biological activity, but only Streptomyces lavendulae showed growth-inhibition against Staphylococcus aureus and Bacillus subtilis.

Actinomycetales↗
PubMed2001

Dermatophilus congolensis infection in goats in Tanzania.

When goats in Eastern Tanzania were screened for skin diseases, Dermatophilus congolensis was isolated from the skin lesions in 8 of 484 animals examined. In one severely affected case, the disease was also characterized by histological studies (Gram stain, Giemsa stain and routine HE studies) and electron microscopy. The histological picture was characterized by hyperkeratosis, parakeratosis, acanthosis, folliculitis and an inflammatory cellular reaction involving the epidermis. Gram stain and Giemsa stain revealed longitudinal and transverse branching filaments in the deeper layers of the epidermis. Ultrastructural studies demonstrated D. congolensis in various morphological forms, ranging from filamentous to tuber-shaped structures, mixed with numerous coccoid bodies of variable size. In some instances, the organisms were geometrically arranged in parallel rows of beading and were present in and among the degenerated epithelial cells. Several host cells showed degenerative changes. Ticks present on the goats were Amblyomma variegatum, Rhipicephalus evertsi, Rhipicephalus pravus and Boophilus sp. The clinical signs, pathological lesions, diagnosis, epidemiology and pathogenesis of the disease are discussed.

Actinomycetales↗
PubMed2002

Prevalence of bovine dermatophilosis in a tropical highland region of Ethiopia.

A study was made of bovine dermatophilosis on 540 animals at a high altitude (2400-2500 m above sea level) in Ethiopia. Eighty-two (15.4%) of the animals were affected by the disease which was more prevalent in local animals than was previously assumed. There was a significant (p < 0.05) difference in the prevalence among different age groups. However, the difference in the prevalence of the disease between males and females was not significant (p > 0.05). Associated risk factors included the relatively high average annual rainfall and humidity, tick infestation (76%) and management, related to the mixed crop-livestock production system. The possible impact of the disease on Ethiopian agriculture is indicated.

Actinomycetales↗
PubMed2003

Numerical phenetic classification of clinically significant aerobic sporoactinomycetes and related organisms.

Clinically significant aerobic sporoactinomycetes, notably agents of mycetoma, were examined for a balanced set of unit characters and the resultant data analysed using standard numerical taxonomic procedures. All save two of the one hundred and seventy three tested strains were assigned to three multimembered cluster-groups, which encompassed sixteen major (4-7 strains), ten minor (2-3 strains) and forty single membered clusters, in an analysis based on the simple matching coefficient and unweighted pair group method with arithmetic averages algorithm. The three cluster-groups were equated with the genus Actinomadura (including Actinocorallia and Streptomyces somaliensis strains), and the genera Nocardiopsis and Streptomyces, and Thermobifida and Thermomonospora, respectively. In a corresponding principal co-ordinates analysis four multimembered groups corresponding to the genera Actinomadura, Nocardiopsis, Streptomyces, and Thermobifida and Thermomonospora were recognised. The causal agents of actinomycetoma were not only assigned to established taxa, notably, to Actinomadura latina, Actinomadura madurae, Actinomadura pelletieri and Streptomyces somaliensis, but also to additional centres of taxonomic variation which were equated with the rank of species. Most of the streptomycetes isolated from clinical material were assigned to clusters equated with the species Streptomyces albus and Streptomyces anulatus. The numerical taxonomic data were used to generate a frequency matrix designed to facilitate the identification of clinically significant Actinomadura, Nocardiopsis and Streptomyces strains to the species level; rapid enzyme tests accounted for eleven out of the twenty-one diagnostic tests.

Actinomycetales↗
PubMed2003

Effect of Azospirillum-mediated plant growth promotion on the development of bacterial diseases on fresh-market and cherry tomato.

AIMS: Plant growth-promoting (PGP) activity of two Azospirillum strains and their effects on foliar and vascular bacterial diseases were evaluated on fresh market and cherry tomato. METHODS AND RESULTS: Tomato seeds were inoculated with A. brasilense Sp7 or Azospirillum sp. BNM-65. Four-week-old plants were challenge-inoculated with Clavibacter michiganensis subsp. michiganensis (bacterial canker) or with Xanthomonas campestris pv. vesicatoria (bacterial spot). Azospirillum-induced PGP was greater on cherry than on fresh-market tomato. Cherry tomato was more resistant to bacterial canker but more susceptible to bacterial spot than the fresh-market tomato. Canker severity was not affected by Azospirillum seed treatments. However, leaf- and plant-death were delayed on Azospirillum-treated plants compared with nontreated controls. Azospirillum increased the bacterial spot severity on cherry but not on fresh-market tomato. CONCLUSIONS: PGP was observed on both tomato genotypes, although growth effects were larger on cherry tomato. Also, Azospirillum treatments may alter tomato susceptibility to bacterial diseases. SIGNIFICANCE AND IMPACT OF THE STUDY: The interaction between PGP rhizobacteria like Azospirillum spp., not known to induce systemic resistance, with plant pathogens distantly located is frequently overlooked. This work demonstrates the importance of this kind of evaluation.

Actinomycetales↗
PubMed2000

Isolation of Dermatophilus congolensis from a cat.

Dermatophilus congolensis was isolated from a cat with dermatitis. The isolate was sensitive to oxytetracyclin, streptomycin and penicillin but resistant to ampicillin, amoxicillin, gentamycin and cefoperazone.

Actinomycetales↗
PubMed2002

A simple random amplified polymorphic DNA genotyping method for field isolates of Dermatophilus congolensis.

Dermatophilus congolensis is the pathogenic actinomycete that causes dermatophilosis in cattle, lumpy wool in sheep and rain scald in horses. Phenotypic variation between isolates has previously been described, but its genetic basis, extent and importance have not been investigated. Standard DNA extraction methods are not always successful for D. congolensis due to its complex life cycle, one stage of which is encapsulated. Here we describe the development of rapid and reliable DNA extraction and random amplified polymorphic DNA (RAPD) methods that can be used for genotyping D. congolensis field isolates. Our results suggest that genotypic variation between isolates correlates with host species. Several DNA extraction methods and RAPD protocols were compared. An extraction method based on incubation of the bacterium in lysozyme, sodium dodecyl sulphate (SDS) and proteinase K treatments and phenolic extraction yielded high-quality DNA, which was used to optimize RAPD-polymerase chain reaction (PCR) protocols for two random primers. An alternative rapid, non-phenolic extraction method based on proteinase K treatment and thermal shock was selected for routine RAPD typing of isolates. DNA extracted from reference strains from cattle, sheep and horse using either method gave reproducible banding patterns with different DNA batches and different thermal cyclers. The rapid DNA extraction method and RAPD-PCR were applied to 38 D. congolensis field isolates. The band patterns of the field and type isolates correlated with host species but not with geographical location.

Actinomycetales↗
PubMed2002

Lemierre's disease caused by co-infection of Arcanobacterium haemolyticum and Fusobacterium necrophorum: a case report.

We report the first case of Lemierre's disease caused by a co-infection with A. haemolyticum and F. necrophorum. A characteristic skin rash and predominant growth on multiple blood cultures suggests a causative role for Arcanobacterium. Failures of penicillin therapy in A. haemolyticum infections should be considered when the initial antibiotic regimen is chosen.

Actinomycetales↗
PubMed2001

Random amplified ribosomal DNA restriction analysis for rapid identification of thermophilic Actinomycete-like bacteria involved in hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is a pulmonary disease characterised by inflammation that can be caused by, amongst other substances, a subset of 4 thermophilic mycelial bacteria: Saccharopolyspora rectivirgula, Saccharomonospora viridis, Thermoactinomyces sacchari, and Thermoactinomyces vulgaris. Air sampling analyses in highly contaminated environments are often performed to evaluate exposure to these species which are difficult and fastidious to identify by conventional techniques. The aim of this study was to use amplified ribosomal DNA restriction analysis (ARDRA) to develop a method of identification for those thermophilic organisms that would be more rapid and simple. Strains of these 4 species were obtained from the American type culture collection (ATCC) and were characterized using biochemical tests and ARDRA patterns obtained on their partial-lenght amplified 16S rDNAs. To validate this approach, ARDRA with two restriction enzymes, TaqI and HhaI, was applied to 49 thermophilic actinomycete-like strains from environmental samples (sawmills). The results obtained show that combining some cultural characteristics and biochemical tests, such as xanthine or hypoxanthine decomposition, growth in the presence of NaCl, lysozyme or novobiocin, and spore resistance over 100 degrees C provide a rough identification and selection of the genera of interest. Consequently, target species could be confirmed by digestion of partial-lenght 16S rDNA with the use of Taql and HhaI restriction enzymes that gave specific restriction patterns. ARDRA analyses on the 49 environmental actinomycete-like organisms revealed the presence of 8 Saccharopolyspora rectivirgula, 2 Saccharomonospora viridis, and 15 Thermoactinomyces vulgaris strains, the other strains had restriction patterns different than those of the species of interest. Results of the present study will be applicable to other potential HP environments such as dairy barns, peat bogs and compost plants.

Actinomycetales↗
PubMed2003

Analysis of conserved non-rRNA genes of Tropheryma whipplei.

The causative agent of Whipple's disease, Tropheryma whipplei, is a slow-growing bacterium that remains poorly-understood. Genetic characterization of this organism has relied heavily upon rRNA sequence analysis. Pending completion of a complete genome sequencing effort, we have characterized several conserved non-rRNA genes from T. whipplei directly from infected tissue using broad-range PCR and a genome-walking strategy. Our goals were to evaluate its phylogenetic relationships, and to find ways to expand the strain typing scheme, based on rDNA sequence comparisons. The genes coding for the ATP synthase beta subunit (atpD), elongation factor Tu (tuf), heat shock protein GroEL (groEL), beta subunit of DNA-dependent RNA polymerase (rpoB), and RNase P RNA (rnpB) were analyzed, as well as the regions upstream and downstream of the rRNA operon. Phylogenetic analyses with all non-rRNA marker molecules consistently placed T. whipplei within the class, Actinobacteria. The arrangement of genes in the atpD and rpoB chromosomal regions was also consistent with other actinomycete genomes. Tandem sequence repeats were found upstream and downstream of the rRNA operon, and downstream of the groEL gene. These chromosomal sites and the 16S-23S rRNA intergenic spacer regions were examined in the specimens of 11 patients, and a unique combination of tandem repeat numbers and spacer polymorphisms was found in each patient. These data provide the basis for a more discriminatory typing method for T. whipplei.

Actinomycetales↗
PubMed2003

Mucosal immune response to Tropheryma whipplei.

Whipple's disease is a rare infectious disease caused by the ubiquitously occurring Tropheryma whipplei in predisposed persons. Genetic or acquired defects in the mucosal and peripheral immune system become apparent as diminished Th1 immune functions with decreased production of IL-12 and IFN-gamma accompanied by an increased secretion of IL-4. These defects may enable T. whipplei to survive and replicate. The recently established cultivation of the bacterium in HEL cells and the isolation from infected intestinal biopsies enable a multitude of experimental possibilities which may lead to an improved diagnosis as well as understanding of the etiology and pathogenesis of Whipple's disease.

Actinomycetales↗
PubMed1994

Catheter-related septicemia caused by a vancomycin-resistant Coryneform CDC group A-5.

A case of catheter-related septicemia, due to Coryneform CDC group A-5, in an 11 yr old boy with acute myelomonocytic leukemia is discussed. The child failed to respond to initial antibiotic therapy, even following the addition of vancomycin. Laboratory studies later showed the organism to be vancomycin resistant but cefotaxime susceptible.

Actinomycetales↗