Pleomorphic Rods Research Articles

First isolation of thermophilic aerobic non-sporulating heterotrophic bacteria from deep-sea hydrothermal vents

Thermophilic aerobic non-sporulating heterotrophic bacteria were isolated for the first time from deep-sea hydrothermal vents. Samples were taken at Snakepit (Mid-Atlantic Ridge) and Guaymas Basin (Gulf of California). Isolates consisting of pleomorphic rods, single cells or pairs, formed filaments of variable length, and grew at 70°C or some up to 80°C. They were halotolerant and unable to grow anaerobically, except some strains in the presence of nitrate. A numerical classification based on phenotypic features was performed on the isolates, including three reference strains Rhodothermus marinus (R-10), Thermus aquaticus (YT-1) and Thermus scotoductus (X-1) and one yellow pigmented Thermus strain. Results from unweighted average linkage (UPGMA) clustering applied to a similarity matrix derived from the simple matching (SSM) coefficient showed the formation of five main clusters which were defined for at least 80% similarity, whereas only three isolates remained outside of the clusters. One reference strain (X-1) clustered with one isolate at a level of 83% and between 76–78% with other clusters. The other reference strains showed less than 55% similarity with the deep-sea isolates.

Structure and swimming behavior of the larva of Haliclona tubifera (Porifera: Demospongiae).

Early developmental stages of Haliclona tubifera are retained by the parent and larvae are released on illumination of dark-adapted colonies. Larvae are parenchymellae without provision for feeding on particulate matter and without identifiable sensory and neuronal elements. Larvae, however, are strongly photonegative on release and remain so throughout the duration of larval existence. The anterior and lateral epidermal fields are composed predominantly of elongate flagellate cells which form a pseudostratified columnar epithelium. Interspersed among elongate cells are globular flagellate cells which, based on ultrastructural criteria, are thought to be secretory in function. The posterior surface is not flagellated and is composed of a cuboidal epithelium. A 5-7 cells wide ring of epidermal cells with flagella 50 μm in length forms a prominent flagellar band separating the posterior from lateral fields. Measurements of swimming speeds in the horizontal plane indicate that H. tubifera larvae swim at speeds intermediate between Halichondria melanadocia, which have a posterior tuft of 25 μm flagella and Haliclona sp, with a posterior ring 75 μm flagella. Morphometric analysis of larval length, larval diameter, and flagellar band diameter shows significant correlations in all pair-wise tests. Band diameter varies less than larval length or width suggesting that it is a conserved trait. A negative allometry exists between band diameter and larval length. As larval length increases elongate flagellar cells of the lateral and anterior surfaces become relatively more important for locomotion. A prominent cup-like sheath of subepidermal cells separates the epidermis from the central region of the larval interior. These cells are not associated with collagen as are cells similar in appearance and location in several other haplosclerid larvae. Their function remains unknown. Spicules occur in the posterior region. As in the adult, these spicules are hastate oxeas, but they are significantly different in length, width, and length/width from those of the adult. Their function is unknown, but several obvious potential functions in both larval and postlarval life exist and await further study. Archeocytes are the dominant cell type of the central region. Bacteria are found inter- and intracellularly. Based on morphological data, they appear to be of a single type, pleomorphic rods without thick walls, but further study utilizing isolates in culture is needed to establish their diversity and identity. Intracellular bacteria are associated with a cell type provisionally designated a bacteriocyte. Three stages of bacteriocytes are described based on anatomical criteria, presence/absence of bacteria, and what appear to be stages in degradation of bacteria. The significance of this association and of the bacteriocyte cell type remain to be explored. © 1993 Wiley-Liss, Inc.

Phascolarctobacterium faecium gen. nov, spec. nov., a Novel Taxon of the Sporomusa Group of Bacteria

Phascolarctobacterium faecium gen.nov., spec. nov. has been described for Gram-negatively staining, nonsporing, chemoorganotrophic, pleomorphic rods that were isolated from koala faeces. Propionate is the main end product of succinate fermentation and growth of satellite colonies occurs around colonies of succinate producing Escherichia coli cells. Phylogenetically, the novel genus groups within the Sporomusa branch of the Clostridium/Bacillus subphylum of Gram-positive bacteria and is a neighbor of Acidaminococcus fermentans .

Endocarditis caused by Rochalimaea henselae

A case of community-acquired, culture-negative, infective endocarditis was diagnosed in a 57-year-old construction worker. Small, pleomorphic gram-negative rods were seen in Brown-Hopps tissue gram stains and Warthin-Starry silver stains. The organism was identified as Rochalimaea henselae by polymerase chain reaction amplification and sequencing of the 16S rDNA gene sequence. This is the first report of infective endocarditis caused by R henselae.

A microbiological study of primary root-caries lesions with different treatment needs.

Samples of altered or carious dentin for microbiological culture were obtained from 301 primary root-caries lesions in 59 patients by means of a standardized sampling procedure. This involved the cleansing of each root surface of extraneous supragingival plaque by means of a hand-held toothbrush and distilled water and the collection of the sample with a sterile dental excavator passed through the entire vertical dimension of each lesion. The total number of colony-forming units (cfu) in each sample and the numbers of mutans streptococci (primarily Streptococcus mutans), lactobacilli, yeasts, and Gram-positive pleomorphic rods (GPPR) were determined. Individual bacterial counts were expressed as log10 (cfu per sample), as a percentage of the total number of bacteria per sample, and as a frequency of isolation from lesions with different clinical diagnostic criteria. Clinical measurements of each lesion were made for color, texture, position relative to the gingival margin, and treatment need. Lesions classified as soft yielded significantly more bacteria, mutans streptococci, lactobacilli, and GPPR than leathery lesions, which yielded more bacteria than hard lesions. Lesions were classified into 5 treatment categories: soft and restore, leathery and restore, leathery and debride of caries; leathery and treat therapeutically; and hard no treatment. The total numbers of bacteria, mutans streptococci, lactobacilli, GPPR, and yeasts decreased significantly with decreasing treatment need. The frequency of isolation of mutans streptococci, lactobacilli, and yeasts was significantly greater from lesions requiring restoration and from lesions situated within 1 mm of the gingival margin. We suggest that the majority of root caries is initiated adjacent to the gingival margin.

Transmission of Necrotizing Hepatopancreatitis in Penaeus vannamei

Necrotizing hepatopancreatitis (NHP) has been an important disease of shrimp mariculture in Texas since it was first recognized in 1985. This disease has resulted in mass mortalities of Penaeus vannamei in commercial growout ponds. Though the cause has remained an enigma, results of a recent morphologic study suggested that the etiology was of one or possibly two intracellular bacteria. The predominant organism associated with necrotic hepatopancreatic tubules was a small, pleomorphic rod, while small numbers of a unique helical organism was sometimes also present. In the present study, successful transmission of necrotizing hepatopancreatitis was accomplished in P. vannamei. Shrimp were injected with a suspension of small, pleomorphic, Gram-negative organisms isolated from spontaneously infected farmed shrimp. Experimentally infected shrimp demonstrated characteristic histologic lesions of NHP and intracellular bacteria in hepatopancreatic epithelial cells. Ultrastructurally, moderate numbers of small pleomorphic rods were demonstrated within hepatopancreatic cells of four infected shrimp, while only a single helical organism was identified. The findings indicate that NHP is the result of a bacterial infection and that the small, pleomorphic, Gram-negative bacterium plays a major role in the pathogenesis of the disease. The relationship of the helical organism in development of the disease and its relationship to the pleomorphic bacterium could not be determined from this study. Shrimp maintained for 20 weeks in a tank that had previously held NHP-infected shrimp failed to develop histologic evidence of hepatopancreatic intracellular infection or evidence of disease. The findings suggest that transmission of this intracellular bacterium may involve a reservoir host and/or that it requires specific environmental conditions.

Preliminary Characterization of a Pleomorphic Gram-Negative Rod Associated with Avian Respiratory Disease

An unidentified, pleomorphic, gram-negative rod (PGNR) bacterium has been isolated from domestic fowl with respiratory disease. The PGNR was isolated in 5% of turkey accessions and 3% of chicken accessions, primarily from the respiratory tract. Preliminary characterization of this organism included reviewing accession records, conducting cultural and biochemical tests, and analyzing cellular fatty acids. The PGNR was also compared with other bacteria capable of inhabiting the avian respiratory system. Biochemical and cellular fatty acid analysis failed to identify the organism, however all 14 isolates were similar.

Description of Osteomyelitis Lesions Associated with Actinomyces pyogenes Infection in the Proximal Tibia of Adult Male Turkeys

Actinomyces pyogenes was isolated from osteomyelitis lesions from the proximal tibia of mature tom turkeys. Gram-stained impression smears of the lesions resulted in bacteria that appeared as club-shaped, gram-positive pleomorphic rods. The bacteria grew better in a reduced-oxygen environment. The lesions were well demarcated and cavernous, ranging from purulent to caseous in consistency.

Characterization of Gram-negative Anaerobic Strains, Isolated from Koala Feces, which Exhibit Satellite Growth and Pleomorphism

Summary Three strains, which showed satellite growth around colonies of concomitant isolates of Escherichia coli , were isolated from koala feces. Experimental inoculation of these strains and E. coli strains on a plate medium anaerobic, gram-negative, and highly pleomorphic rods. They were bile resistant and asaccharolytic, and produced only a trace amount of propionic acid from peptone yeast-extract Fildes-solution with glucose broth. Their growth was stimulated by succinic acid but completely inhibited by fumaric acid. Subsequent biochemical analysis revealed that the strains produced a large amount of propionic acid from peptone yeast-extract (PY) broth supplemented with sodium succinate. A PY broth agar plate, which contained 30% E. coli -metabolized PY broth, enhanced growth of the strains, and it was found that this spent broth contained succinic acid produced by the E. coli . The evidence suggests that the observed satellite growth was due to succinic acid produced by E. coli strains.

Microscopic and ultrastructural studies of necrotizing hepatopancreatitis in Pacific white shrimp (Penaeus vannamei) cultured in Texas.

Granulomatous hepatopancreatitis of unknown etiology has been considered an important disease of Texas shrimp mariculture since 1985. Samples of Pacific white shrimp (Penaeus vannamei) were collected during 1986, 1987, and 1990 from three farms and an experimental mariculture facility with histories of production loss and increased mortality rates. Histologic and ultrastructural examination of shrimp from the four sites demonstrated two morphologically distinct, Gram-negative, double-enveloped, intracytoplasmic bacteria in necrotic hepatopancreatic epithelium. The more numerous small, pleomorphic rod as well as the helical organism are both taxonomically unclassifiable. The helical organism lacked ultrastructural characteristics of previously described helical or spiral bacteria. The relationship between the two organisms is unknown, but the pleomorphic rod is thought to play a major role in the disease. The role of a bacterial agent(s) in subsequent disease episodes is suggested by the observation that the use of oxytetracycline-medicated feed resulted in increased production and survival. Hepatopancreatic tubular epithelial necrosis and shrimp mortality correlated directly with the extent of infection by the small pleomorphic rod. Individual discrete bacteria were identified microscopically by Steiner and Steiner's method. Three major developmental stages of the disease were characterized based on the extent and number of hepatopancreatic tubular epithelial cells containing bacteria, the degree of tubular interstitial inflammation, and the extent and chronicity of tubular necrosis. Additional studies are needed to clarify the roles of the different bacteria identified and the potential role of environmental factors on the disease process.

Soft-tissue and osseous lesions caused by bacillary angiomatosis: unusual manifestations of cat-scratch fever in patients with AIDS.

Cat-scratch disease, caused by a pleomorphic Gram-negative rod known as the cat-scratch bacillus, has many rare and varied complications and unusual manifestations [1]. Recent reports [2-6] have described bacillary angiomatosis as a new manifestation of systemic cat-scratch disease seen in patients with AIDS who have cutaneous lesions, subcutaneous nodules, or osteolytic lesions. We report a case of bacillary angiomatosis that was manifested as a vascular softtissue mass in which cat-scratch bacilli were shown by electron microscopy. To our knowledge, no similar cases of softtissue masses in systemic cat-scratch disease have been reported. As our case illustrates, systemic cat-scratch disease has clinical and radiologic features that resemble both benign and malignant diseases. Although certain radiologic and dinical findings may suggest the diagnosis of systemic catscratch disease, a definitive diagnosis is made only on the basis of biopsy specimens examined by using either special stains or electron microscopy.

Coryneform bacteria in infectious diseases: clinical and laboratory aspects

Coryneform isolates from clinical specimens frequently cannot be identified by either reference laboratories or research laboratories. Many of these organisms are skin flora that belong to a large number of taxonomic groups, only 40% of which are in the genus Corynebacterium. This review provides an update on clinical presentations, microbiological features, and pathogenic mechanisms of infections with nondiphtheria Corynebacterium species and other pleomorphic gram-positive rods. The early literature is also reviewed for a few coryneforms, especially those whose roles as pathogens are controversial. Recognition of newly emerging opportunistic coryneforms is dependent on sound identification schemes which cannot be developed until cell wall analyses and nucleic acid studies have defined the taxonomic groups and all of the reference strains within each taxon have been shown by molecular methods to be authentic members. Only then can reliable batteries of biochemical tests be selected for distinguishing each taxon.

Microbiology of Root Surface Caries in Humans

Studies on the microbiology of root surface caries between 1970 and 1975 placed emphasis on Gram-positive pleomorphic filamentous rods, particularly Actinomyces viscosus and Actinomyces naeslundii. Both of these species had been shown to produce root surface caries in experimental animals. Since this time, studies have placed more emphasis on Streptococcus mutans, and S. mutans and Lactobacillus are significant in prediction of root surface caries risk in patients. Subsequent studies confirmed an association between S. mutans and 'soft' or 'initial' root lesions. Thus, it is important when determining the microflora of root surface lesions to make careful characterization of the state of the lesion. A second important aspect of the analysis of bacterial communities associated with root surface caries is better definition of the organisms. Most studies have concentrated on 'target organisms' S. mutans, S. sanguis, A. viscosus, A. naeslundii, Lactobacillus, and Veillonella. However, it has been known for 17 years that the Actinomyces associated with the lesions may be variants of A. viscosus and A. naeslundii. Such strains (intermediate strains) have been described in taxonomic studies of Actinomyces, yet little is known of the differences in physiology of these strains or their relationship to root surface caries. A similar situation exists with oral Streptococcus where new taxonomic divisions are being proposed. Recognition of the potential diversity within the 'target' genera of root surface caries could yield valuable data. Recent studies suggest that this is so, since samples from root surface lesions which contain S. mutans and Lactobacillus show a high isolation of S. mitis 1 and no isolations of A. naeslundii. Careful definition of the lesions of root surface caries and the flora will allow analysis to relate a specific bacterial community to the state fo the lesion and assist in monitoring the control of the lesion through fluoride and antibacterials.

Identification procedures for oral Actinomyces species

Rapid tests for carbohydrate fermentation, nitrate reduction and enzymic reactions with single reagents were used for species identification of 144 isolates being gram-positive pleomorphic rods and belonging to the genus Actinomyces. The isolates derived from human supragingival and subgingival plaque. The results were compared with those obtained with reference strains as well as other previously identified strains belonging to Actinomyces and to the related genera Arachnia, Bifidobacterium, Propionibacterium and Rothia. The results showed that species identification within the genus Actinomyces was possible with the tests studied. A key for identification work is hereby provided.

Coryneform bacteria in infectious diseases: clinical and laboratory aspects.

Coryneform isolates from clinical specimens frequently cannot be identified by either reference laboratories or research laboratories. Many of these organisms are skin flora that belong to a large number of taxonomic groups, only 40% of which are in the genus Corynebacterium. This review provides an update on clinical presentations, microbiological features, and pathogenic mechanisms of infections with nondiphtheria Corynebacterium species and other pleomorphic gram-positive rods. The early literature is also reviewed for a few coryneforms, especially those whose roles as pathogens are controversial. Recognition of newly emerging opportunistic coryneforms is dependent on sound identification schemes which cannot be developed until cell wall analyses and nucleic acid studies have defined the taxonomic groups and all of the reference strains within each taxon have been shown by molecular methods to be authentic members. Only then can reliable batteries of biochemical tests be selected for distinguishing each taxon.

Diphtheroids as Ocular Pathogens

Unlike Corynebacterium diphtheriae and Propionibacterium acnes, the pleomorphic gram-positive rods known as diphtheroids are generally regarded as nonpathogenic contaminants of the human external eye. We reviewed five years of microbiology records at Wills Eye Hospital and studied a series of eight cases of apparently infectious keratitis associated with heavy growth of diphtheroids on cultures of ulcer scrapings. All of these cases included indolent ulcers that occurred almost exclusively in elderly patients (mean age, 72 years; range, 11 to 92 years). All patients had preexisting ocular conditions that compromised the corneal surface such as exposed corneal sutures, eyelid surgery, aphakic extended wear contact lenses, viral keratitis, and diabetes mellitus. No other pathogens were isolated. All infections responded well to antibiotic therapy with all organisms sensitive to cefazolin and all but one sensitive to gentamicin.

Taxonomic characters and cultural conditions of a bacterial strain, AT-25, which produces a galactan sulfate with antithrombin activity.

Strain AT-25 isolated from a soil sample collected in Japan, showed potent antithrombin activity in its culture filtrate. The strain was a strictly aerobic, gram-positive and pleomorphic rod. The properties of the strain, especially the presence of LL-diaminopimelic acid (LL-DAP), tetrahydrogenatedmenaquinone with eight isoprene units (MK-8(H4)), and DNA with 72.9mol% of guanine plus cytosine, indicate that strain AT-25 is closely related to Arthrobacter simplex and Arthrobacter tumescens, while these species do not belong to the genus Arthrobacter in strict meaning. Theunique characteristics of strain AT-25 are requirement of SO42- for growth and the production of a galactan sulfate with antithrombinactivity. The most suitable medium for the production of galactan sulfate was a fermentation medium consisting of 0.05% Na2SO4, 2% glycerol, 0.5% (NH4)2HPO4, 0.1% KH2PO4, and 0.1% yeast extract (pH 7.2).

Halobacterium lacusprofundi sp. nov., a Halophilic Bacterium Isolated from Deep Lake, Antarctica

Summary Halobacterium lacusprofundi sp. nov. is described based on the characteristics of two strains (ACAM 32, ACAM 34) of red halophilic bacteria isolated from Deep Lake, a hypersaline, Antarctic lake. Bacteria which could grow on media prepared with undiluted Deep Lake water have not been isolated previously from Deep Lake. Cells were pleomorphic rods which lysed when suspended in distilled water. Unlike other halobacteria, the strains grew at 4°C, albeit very slowly. Fastest generation times (11 h) occurred between 31–37°C. The strains were not proteolytic, did not produce acids from sugars, but utilized a wide range of carbon sources including sugars, alcohols, and organic acids for growth. The strains grew in media with Mg ++ concentrations ranging from 0.005 to 1.0 mol/l and with NaCl concentrations ranging from 1.5 mol/l to saturation. Cells contained isoprenoid neutral lipids typical of halophilic archaebacteria. The major constituents were diphytanyl glyceryl ether, squalene and dihydrophytol. Approximately 30% of the total ether lipids consisted of at least four glyceryl ethers containing one or more double bonds in the phytenyl group. Also present were squalane, dihydrosqualene, tetrahydrosqualene, dihydrophytol and phytol. The G+C content of the major component DNA was 65 to 66 mol%. Satellite band DNA was present with G+C contents ranging from 54 to 57 mol%. Analysis of the 16S rRNA catalogue showed strain ACAM 34 was most closely related to Halobacterium saccharovorum ATCC 29252 (S AB value 0.74) but only distantly related to Haloferax volcanii ATCC 29605 (S AB value 0.43), Haloarcula vallismortis ATCC 29715 (S AB value 0.36), Halococcus morrhuae ATCC 17082 (S AB value 0.39) or Natronococcus occultus NCMB 2192 (S AB value 0.47). The type strain is UQM 3107 (ACAM 34).

Light and electron microscopic features of tropical ulcer.

The histopathological features of 20 tropical ulcers with the electron microscopic findings on seven biopsy specimens are reported. The main findings were loss of epidermis associated with extensive dermal oedema, infiltration by polymorphonuclear leucocytes, and disruption of collagen bundles. The presence of micro-organisms at the site of tissue damage was shown and compared with the morphology of the organisms grown in culture. The most commonly identified bacteria were pleomorphic rods whose electron microscopic appearances accorded most closely with Fusobacteria grown in vitro. Spirochaetes, identified ultrastructurally as Treponema sp, were also present. There was no evidence of vasculitis to explain the rapid onset of ulceration, but necrotic changes seen in the dermis and the inflammatory cell infiltrate suggest that, associated with cell necrosis, bacteria previously shown in vitro have an important role in the pathogenesis of tropical ulcers.

Ultrastructural Observations in Cat Scratch Disease

Because the causative bacterium of cat scratch disease has not been definitively cultured or fully characterized, the authors have studied its ultrastructure in lymph node biopsies from two patients using glutaraldehyde-fixed tissue. In both specimens, the organisms were invariably extracellular, forming small groups within bundles of collagen fibrils. Their appearance was similar in necrotic and viable regions of the nodes, although in the latter sites they could not be identified by light microscopic examination with the Warthin-Starry stain. The bacteria were pleomorphic rods, and, despite faint gram-negative staining, their walls were consistently thick and homogeneous.