Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ACTINOMYCES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2000

Sensitization of Actinomyces naeslundii and Streptococcus sanguis in biofilms and suspensions to acid damage by fluoride and other weak acids.

Fluoride and other weak acids, such as benzoate, indomethacin, salicylate and sorbate, were found to be sensitizers for acid killing of cells of Actinomyces naeslundii ATCC 19246 and Streptococcus sanguis NCTC 10904 in suspensions or in mono-organism biofilms on glass slides. These bacteria are among the more acid-sensitive organisms from dental plaque and were killed when acidified to pH values between 3.5 and 4.0. Biofilm cells were more resistant than cells in suspensions, especially in terms of the fraction of the initial population surviving acidification. The mechanism for sensitization to acid killing by fluoride and the other weak acids involved enhanced transmembrane transport of protons, reflected by increases in measured proton permeabilities of the cells. Thus, the weak acids thwarted the functions of F(H+)-ATPases in extruding protons and protecting cells against acid damage. Fluoride sensitization of biofilms or cells in suspensions to acid damage occurred rapidly. There was a delay in sensitization of biofilms by indomethacin and higher molecular weight acids which was interpreted in terms of diffusion limitation of sensitizer penetration. Overall, it seemed that weak-acid sensitization to acid killing is a general phenomenon that occurs not just for oral bacteria but also for organisms in food, soil, and other acidified environments.

Actinomyces↗
PubMed2002

Actinomyces neuii and neonatal sepsis.

Actinomyces neuii belongs to the coryneform bacteria. In the case presented here this gram-positive rod had to be considered the pathogen causing not only the chorioam nionitis but also the neonatal sepsis. Conventional therapeutic regimes are effective due to the high sensitivity of A. neuii to beta-lactam antibiotics.

Actinomyces↗
PubMed1981

Actinomyces in the vaginas of women with and without intrauterine contraceptive devices.

Either Actinomyces israeli, A. naeslundii, or Arachnia propionica was found, by immunofluorescence studies, in cervicovaginal mucus from 36% of 50 women. One or more of these organisms were found in a surprising 27% of those with neither intrauterine contraceptive devices (IUDs) nor intravaginal foreign bodies. The only common finding was abundant vaginal mucus, and no clinical features were more serious than vaginal itching, odor, or vague discomfort. Among those women who harbored actinomycetes, the average duration of continuous IUD use was 5.3 years; the comparable figure for those with no infection was 2.1 years.

Actinomyces↗
PubMed1977

Fusobacterium in presumed Actinomyces canaliculitis.

Based on stained smears of material obtained from the canaliculus, three cases of canaliculitis were presumed to be caused by Actinomyces. Cultures of these cases showed Fusobacterium to be the probable infectious agent producing the disease.

Actinomyces↗
PubMed1982

Cell-mediated and humoral immune responses of guinea-pigs to the oral bacterium Actinomyces viscosus.

Actinomyces viscosus is a Gram-positive facultative rod indigenous to most human mouths. The guinea-pig was evaluated as a model for assessing cellular immune responses to a human strain of A. viscosus. Guinea-pigs, immunized with heat-killed A. viscosus cells or a water-soluble extract from A. viscosus (AVS), were tested for delayed-type hypersensitivity responses to A. viscosus 4 weeks after immunization. A week later, the guinea-pigs were terminated. Lymphocytes from peripheral blood, lymph node and spleen were tested for in-vitro blastogenic responses to heat-killed A. viscosus or the water-soluble extract. Plasma from these guinea-pigs were tested for the presence of precipitating antibodies. Positive in-vivo delayed-type hypersensitivity reactions and antibody responses to AVS occurred only in immunized guinea-pigs. A strong in-vitro blastogenic response to AVS or heat-killed A. viscosus occurred in lymphocytes from immunized guinea-pigs, but a weak response was detected in un-immunized animals. These data suggest that the guinea-pig can be used to evaluate different parameters of the immune response to oral bacteria such as A. viscosus.

Actinomyces↗
PubMed1982

Differences in lymphoproliferative responses to the bacterium Actinomyces viscosus in various mammalian species.

A water-soluble extract of Actinomyces viscosus (AVS) was tested for its capacity to induce DNA synthesis in lymphocytes from man, monkeys, mice and guinea pigs. The results indicated that the AVS induced an in-vitro lymphoproliferative response, as assessed by tritiated thymidine incorporation, in mouse-spleen cells, in the majority of human peripheral blood samples tested and in macaque monkey spleen cells. The AVS also elicited a blastogenic response from spleen, lymph node and peripheral blood lymphocytes from guinea pigs immunized with A. viscosus. The AVS did not elicit a lymphoproliferative response from human-cord blood cells, monkey peripheral blood lymphocytes, or peripheral blood and spleen lymphocytes from non-immunized guinea pigs. Thus there was a difference in the ability of A. viscosus to induce DNA synthesis in lymphocytes from the different animal species tested.

Actinomyces↗
PubMed1982

The effect of extracts from human dental plaque, oral streptococci and actinomyces bacteria on HELA cell growth, [3H]-thymidine uptake and 51Cr release.

Dialysed extracts from dental plaque and a number of species of oral streptococci and actinomycetes have been investigated for their effects on cell growth, [3H]-thymidine uptake and 51Cr release from HeLa cell cultures. Eight of the 15 extracts inhibited cell growth and all but one inhibited [3H]-thymidine incorporation. None of the extracts stimulated 51Cr release from prelabelled cells. These results suggest that many of the species of streptococci and actinomyces found in the mouth and in dental plaque are capable of producing high mol. wt substances that interfere with HeLa cell cultures by inhibiting [3H]-thymidine uptake and DNA synthesis but do not affect the degree of intactness of the external cell membrane.

Actinomyces↗
PubMed1983

Activation of the alternate complement pathway by peptidoglycan of Actinomyces viscosus, a potentially pathogenic oral bacterium.

Peptidoglycans and cells walls from Actinomyces viscosus, Staphylococcus aureus, and group A streptococcus were compared for their relative abilities to activate the alternate complement pathway (ACP). On the dry-weight basis, the peptidoglycan from A. viscosus was 3.5 times more active than group A streptococcal peptidoglycan and 15.6 times more active than Staph. aureus peptidoglycan in activating the ACP. Consequently A. viscosus peptidoglycan is one of the most potent ACP-activators reported to date. For both A. viscosus and group A streptococcus, the peptidoglycan was a better ACP activator than cell walls from the same organism (125- and 52-fold, respectively) indicating that the peptidoglycan is probably the most important subcellular ACP-activator in these microorganisms. In contrast, cell walls from Staph, aureus were 9 times more active than peptidoglycan from Staph. aureus in activating the ACP, presumably because teichoic acids are the most important subcellular ACP activator in this microorganism.

Actinomyces↗
PubMed1985

Peptidoglycan from the potentially pathogenic oral bacterium Actinomyces viscosus is a B-cell mitogen.

Cell walls and peptidoglycan from Actinomyces viscosus, strain M-100 were compared for their ability to act as mitogens with spleen cells from germ-free Fischer rats. The cell walls were prepared from trypticase soy broth grown whole cells using a French press, followed by two consecutive washes with 0.1 M tris-HCl buffer, pH 8.0, 1 M NaCl and distilled water. Peptidoglycan was prepared from cell walls by three consecutive formamide extractions at 165 degrees C. On a dry-weight basis, the peptidoglycan was a significantly-better mitogen than cell walls, suggesting that the peptidoglycan is the major mitogenic component of A. viscosus cell walls. Mononuclear spleen cells were separated on a Nylon-wool column into a non-adherent subpopulation enriched for T lymphocytes and a weakly-adherent, plunger-removable subpopulation enriched for B lymphocytes. The non-adherent T-cell subpopulation responded strongly to the T-cell mitogen PHA, but was unresponsive to both the peptidoglycan and cell walls from A. viscosus. In contrast, the weakly-adherent enriched B-cell subpopulation was less responsive to PHA, but was strongly stimulated by A. viscosus peptidoglycan and cell walls. These results indicate that peptidoglycan and cell walls from A. viscosus are B-cell mitogens.

Actinomyces↗
PubMed1992

Role of Porphyromonas gingivalis 40-kDa outer membrane protein in the aggregation of P. gingivalis vesicles and Actinomyces viscosus.

Porphyromonas gingivalis, an important pathogen in periodontitis, produces extracellular vesicles that aggregate with Actinomyces viscosus cells. A 40-kDa outer membrane protein (OMP)-coding gene from P. gingivalis was cloned and the protein was found to be localized in these vesicles. The recombinant 40-kDa OMP did not show aggregation activity. However, affinity-purified antibody against the recombinant protein significantly inhibited aggregation of P. gingivalis vesicles with A. viscosus cells. The antibody also inhibited cellular coaggregation of several strains of P. gingivalis with A. viscosus cells, but not with other periodontal pathogens. Moreover, aggregation of A. viscosus cells with P. gingivalis vesicles was inhibited in a dose-dependent manner by pre-treatment of the A. viscosus cells with the recombinant protein. These findings suggest that the 40-kDa OMP may be an important aggregation factor of P. gingivalis.

Actinomyces viscosus↗
PubMed1996

Biochemical studies on LevJ, a fructanase from Actinomyces naeslundii T14V.

The Actinomyces naeslundii T14V gene levJ encodes a sucrase with fructanase activity and may be responsible for the fructanase activity observed bound to the surface of A. naeslundii T14V cells. A large proportion of LevJ expressed in Escherichia coli was translocated to the periplasm, and translocation and enzymatic activity were not affected by deletion of a putative cell-wall anchor sequence. The pH optimum of the enzyme was found to be between 5.5 and 6.5 whether the substrate was sucrose or inulin, although inulinase activity was more sensitive than sucrose activity to perturbation of the pH from the optimum. The relation between LevJ inulinase activity and pH was similar to that of A. naeslundii whole cells. LevJ exhibited standard saturation kinetics with sucrose, and the K(m) was calculated to be 89 mM, but it was not possible to calculate a K(m) for inulin. Evidence for inhibition of inulinase activity but not sucrase activity by high concentrations of inulin was obtained.

Actinomyces↗
PubMed1979

The cell wall-associated levansucrase of Actinomyces viscosus.

Actinomyces viscosus produces both a soluble extracellular levansucrase and a cell wall-associated levansucrase. The enzyme from cell walls was solubilized by lysozyme digestion. The soluble extracellular and cell wall-associated forms of the enzyme were compared and appeared to be identical, based on molecular weight estimations, kinetic parameters, and reactions with antisera. The product of both forms of the enzyme was a high molecular weight, branched levan, as shown by its reactivity with myeloma proteins specific for beta(2 leads to 1) and for beta(2 leads to 6) linkages in fructosans. Although levansucrase remained tightly bound to the levan which it synthesized, the enzyme did not bind to exogeneously added levan. Regarding the potential pathogenicity of the levan product, pure levan, produced using purified levansucrase, did weakly activate complement by the alternative pathway. However, the pure levan did not directly cause bone resorption in an in vitro bone resorption assay.

Actinomyces↗
PubMed1984

Influence of removal of intrauterine contraceptive devices on colonisation of the cervix by actinomyces-like organisms.

An overall prevalence rate of actinomyces-like organisms (ALO) in cervical smears from intrauterine contraceptive device (IUCD) users of 3% (79/2, 734) was found, with a rate of 2% and 22.6% for copper and inert IUCD users. Although the users of the inert IUCDs were older, and their devices had been in situ longer, these factors did not account for the significant difference between the two types of IUCD. Fifty-five patients were counselled and given a leaflet on ALO. Fourteen IUCD users with ALO positive smears who had their devices removed had mild or moderate pelvic pain or discharge. Six others who were asymptomatic had the IUCD removed at their own request. All fifty-five patients were re-examined six months to one year later, and a smear was repeated. Only one woman required later removal of the IUCD because of dyspareunia with pelvic tenderness. After removal of the IUCD, and without antibiotic therapy, in 100% (20/20) of the women, ALO colonisation was no longer found six to twelve months later. This applied even to seven women who had had a new copper IUCD inserted immediately after removal of the index device.

Actinomyces↗
PubMed1986

Actinomyces israelii-associated salpingitis.

Actinomyces israelii was identified in samples from the oviducts of 4/100 women with salpingitis diagnosed by laparoscopy. All four cases healed on 'routine' treatment. Possible pathogenic mechanisms for the development of actinomycosis are discussed.

Actinomyces↗
PubMed1983

Actinomyces israelii in osteoradionecrosis of the jaws. Histopathologic and immunocytochemical study of five cases.

Five surgically treated patients with osteoradionecrosis of the jaws are presented. The clinical history of the disease varied from 3 to 17 years. In three cases the progression of the disease was enhanced by surgical procedures performed in the irradiated area causing exfoliation of the premaxillary area in one case and spontaneous mandibular fracture in two cases. Actinomyces israelii was demonstrated in tissue sections of all five cases by using FITC-labeled specific antiserum and additionally with peroxidase-antiperoxidase method in one case. Candida was found in histologic sections of three cases. Radiation damage in the oral soft tissues and jawbones makes the atmosphere favorable for anaerobic microorganisms. The present results indicate that the role of A. israelii in the pathogenesis of osteoradionecrosis of the jaws has not been fully appreciated.

Actinomyces↗
PubMed1991

Nonhealing extraction site due to Actinomyces naeslundii in patient with AIDS.

There are many oral complications of human immunodeficiency virus infection. One of the infectious sequelae is contamination and delayed healing of the tooth extraction site. We report a case of a nonhealing extraction site in a patient with the acquired immunodeficiency syndrome. Histologic and microbiologic evaluation determined the causative species of bacterium to be Actinomyces naeslundii. Diagnosis and treatment are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Complement activation by individual and combinations of monoclonal antibodies to Actinomyces viscosus T14V fimbriae: a probe for epitope distribution on these polymeric proteins.

The spatial requirements for IgG activation of the classical complement pathway has provided a basis for utilizing complement consumption by individual and pairs of monoclonal antibodies (mAbs) to compare the repeating epitope patterns of the type 1 and type 2 fimbriae of Actinomyces viscosus T14V and to examine the co-operative effects of mAbs against these polymeric proteins. Three of five mAbs specific for the type 1 fimbriae consumed complement when assayed individually. Four patterns of complement consumption were detected with pairs of these mAbs: inhibition, addition, enhancement or synergy. Inhibition occurred when both members of a pair reacted with the same epitope but only one consumed complement. A strictly additive effect was observed if both mAbs consumed complement and, in addition, recognized the same epitope. Complement consumption by mAbs against certain epitopes was enhanced by non-complement consuming mAbs that reacted with different epitopes. Synergy was observed with extremely low concentrations of two mAbs each of which reacted with a different epitope and consumed complement. In contrast to the anti-type 1 mAbs, only one of seven mAbs against the type 2 fimbriae consumed more than 20% of the available complement. Pairs of anti-type 2 mAbs exhibited only inhibition or synergy. The latter effect was particularly striking as pairs containing mAbs that reacted with different epitopes and failed to consume complement or were minimally active when assayed individually were extremely efficient. These data indicated that the spatial arrangements of individual mAbs bound to repeating epitopes in the type 1, but not the type 2, fimbriae were appropriate for activation of complement. Thus, the repeating epitope patterns of the two types of fimbriae apparently differ.

Actinomyces↗
PubMed1992

Pericarditis, pneumonia and brain abscess due to a combined Actinomyces--Actinobacillus actinomycetemcomitans infection.

A patient is described in whom there developed a pulmonary infiltrate and constrictive pericarditis caused by a combined Actinomyces and Actinobacillus actinomycetemcomitans infection, presumably originating from his poor dentition. The diagnosis was only made following repeated thoracotomy. After surgery, long-term treatment with antibiotics led to complete clinical recovery. None the less, some months later he was found to have a brain abscess which resolved during a further course of antibiotics. The variable clinical picture of actinomycosis is discussed, as well as the role of other bacteria frequently associated with actinomycotic infection, in particular Actinobacillus actinomycetemcomitans. The therapeutic implications are described.

Actinobacillus Infections↗