Episymbiotic Saccharibacteria suppresses gingival inflammation and bone loss in mice through host bacterial modulation.

Saccharibacteria (TM7) are obligate epibionts living on the surface of their host bacteria and are strongly correlated with dysbiotic microbiomes during periodontitis and other inflammatory diseases, suggesting they are putative pathogens. However, due to the recalcitrance of TM7 cultivation, causal research to investigate their role in inflammatory diseases is lacking. Here, we isolated multiple TM7 species on their host bacteria from periodontitis patients. These TM7 species reduce inflammation and consequential bone loss by modulating host bacterial pathogenicity in a mouse ligature-induced periodontitis model. Two host bacterial functions involved in collagen binding and utilization of eukaryotic sialic acid are required for inducing bone loss and are altered by TM7 association. This TM7-mediated downregulation of host bacterial pathogenicity is shown for multiple TM7/host bacteria pairs, suggesting that, in contrast to their suspected pathogenic role, TM7 could protect mammalian hosts from inflammatory damage induced by their host bacteria.

A rare case of Actinomyces skin and soft tissue infection in an end-stage kidney disease patient with a review of the literature.

End-stage kidney disease (ESKD) patients are a commonly overlooked immunocompromised population that places them at risk for rare infections. We describe the case of a 78-year-old man with a history of ESKD managed with thrice weekly in-center hemodialysis who had a prolonged episode of left elbow pain and drainage and was eventually found to have a skin and soft tissue infection from Actinomyces radingae. We review the bacteriology of Actinomyces spp. and the experiences of other providers who have treated actinomycosis in individuals with ESKD. The anatomic sites and demographics of these individuals are heterogeneous, but they all generally require a long antibiotic course with a beta-lactam and portend to a good prognosis. High index of suspicion is needed to identify rare and atypical infections in the ESKD population.

[Actinomycosis]. / Actinomycose.

Actinomycosis is a chronic bacterial infection, caused by the genus Actinomyces, commensal of the digestive and genital tract. The most common presentation of the disease affects the cervicofacial region, but other anatomical sites in the abdomen, thorax and central nervous system may be involved. Differential diagnosis includes neoplasia. Prolonged culture of deep samples in an anaerobic environment is the gold standard of the diagnosis. The treatment of choice is intravenous penicillin G followed by oral amoxicillin for a total duration of 6 to 12 months. However, depending on the location and response to antibiotics, shorter therapy may be considered.

L'actinomycose est une infection bactérienne chronique, causée par le genre Actinomyces, commensal des tractus digestif et génital. La forme la plus fréquente de la maladie touche la région cervico-faciale, mais d'autres sites anatomiques dans l'abdomen, le thorax et le système nerveux central peuvent être concernés. Le diagnostic différentiel se fait souvent avec une néoplasie. La mise en culture prolongée de prélèvements profonds en milieu anaérobe est le gold standard du diagnostic. Le traitement de choix est la pénicilline G intraveineuse, suivi d'un relais per os par amoxicilline, pour une durée totale de 6 à 12 mois. Cependant, selon la localisation et la réponse aux antibiotiques, une thérapie plus courte peut être envisagée.

Liquid-Infused Structured Titanium Surfaces: Antiadhesive Mechanism to Repel Streptococcus oralis Biofilms.

To combat implant-associated infections, there is a need for novel materials which effectively inhibit bacterial biofilm formation. In the present study, the antiadhesive properties of titanium surface functionalization based on the "slippery liquid-infused porous surfaces" (SLIPS) principle were demonstrated and the underlying mechanism was analyzed. The immobilized liquid layer was stable over 13 days of continuous flow in an oral flow chamber system. With increasing flow rates, the surface exhibited a significant reduction in attached biofilm of both the oral initial colonizer  Streptococcus oralis and an oral multispecies biofilm composed of S. oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis. Using single cell force spectroscopy, reduced S. oralis adhesion forces on the lubricant layer could be measured. Gene expression patterns in biofilms on SLIPS, on control surfaces, and expression patterns of planktonic cultures were also compared. For this purpose, the genome of S. oralis strain ATCC 9811 was sequenced using PacBio Sequel technology. Even though biofilm cells showed clear changes in gene expression compared to planktonic cells, no differences could be detected between bacteria on SLIPS and on control surfaces. Therefore, it can be concluded that the ability of liquid-infused titanium to repel S. oralis biofilms is mainly due to weakened bacterial adhesion to the underlying liquid interface.

Intrageneric and Intergeneric Interactions Developed by Oral Streptococci: Pivotal Role in the Pathogenesis of Oral Diseases.

Oral streptococci are among the most abundant genera present in the oral cavity. They are usually the first colonizers of oral surfaces and they develop extensive microbial interactions, playing a fundamental role in the pathogenesis of oral diseases such as dental caries and periodontitis. In addition to physical adherence, streptococcal cells also exchange messages with cells from another Streptococcus spp. and other microorganisms in the form of metabolites and signaling molecules. In this review, we focused on these intrageneric and intergeneric interactions, and their association with oral diseases.

Actinomyces naeslundii causing pulmonary endobronchial Actinomycosis - A case report.

Actinomyces naeslundii is a commensal flora of the oral cavity and is generally considered as an avirulent saprophytic bacterium in immunocompetent patients. It can become an opportunistic anaerobic pathogen in oral cavity in patients with poor oral hygiene or tooth extraction and can cause periodontal disease. Pulmonary Actinomycosis is a rare manifestation and may be suspected in middle-aged male patients with cough and hemoptysis showing radiological findings of a peripheral mass or chronic consolidation in whom repeated aerobic cultures have yielded negative results. Here, we report isolation of A. naeslundii from the bronchoalveolar lavage sample from an immunocompetent patient who presented with chronic nonresolving pneumonia of 6 months duration.

Actinomyces odontolyticus infection 3 months post-robotic-assisted laparoscopic prostatectomy.

Actinomyces odontolyticus infection is a rare bacterial infection with only 46 cases reported from its discovery in 1958. This case highlights an immunocompetent patient who presented with an infected lymphocele and bacteraemia following a robotic-assisted laparoscopic prostatectomy and extended pelvic lymph node dissection 3 months previously. He was treated for a fever of unclear origin initially using amoxicillin, gentamicin and metronidazole. Subsequently, he was found to have an infected lymphocele, which required surgical drainage. He was discharged 19 days after admission with three times daily oral amoxicillin which is to be continued for 6-12 months. This case highlights the need for effective communication between the laboratory and medical teams, and the importance of prompt source control.

Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm.

INTRODUCTION: Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation. METHODS: Highly pure and structurally intact Lp.LTA was purified from L. plantarum. Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans, and Enterococcus faecalis were co-cultured to form oral multispecies biofilm in the presence or absence of Lp.LTA on culture plates or human dentin slices. Preformed biofilm was treated with or without Lp.LTA, followed by additional treatment with intracanal medicaments such as calcium hydroxide or chlorhexidine digluconate. Confocal microscopy and crystal violet assay were performed to determine biofilm formation. Biofilm on human dentin slices was visualized with a scanning electron microscope. RESULTS: Biofilm formation of multispecies bacteria on the culture dishes was dose-dependently reduced by Lp.LTA compared with the nontreatment control group. Lp.LTA also inhibited multispecies biofilm formation on the dentin slices in a dose-dependent manner. Interestingly, Lp.LTA was shown to reduce preformed multispecies biofilm compared with the nontreatment group. Moreover, Lp.LTA potentiated the effectiveness of the intracanal medicaments in the removal of preformed multispecies biofilm. CONCLUSIONS: These results suggest that Lp.LTA is a potential anti-biofilm agent for treatment or prevention of oral infectious disease, including apical periodontitis, which is mainly caused by multispecies bacterial biofilm.

Novel anti-biofouling light-curable fluoride varnish containing 2-methacryloyloxyethyl phosphorylcholine to prevent enamel demineralization.

We evaluated the efficacy of light-curable fluoride varnish (LCFV) that contains 2-methacryloyloxyethyl phosphorylcholine (MPC) in terms of anti-biofouling properties and prevention of tooth enamel demineralization. MPC was mixed with and incorporated into LCFV at 0 (control), 1.5, 3.0, 5.0, 10.0, 20.0, and 40.0 weight percentage (wt%). Addition of high wt% of MPC resulted in increased film thickness and decreased the degree of conversion, indicating loss of the advantageous properties of LCFV. Addition of 1.5, 3, or 5 wt% MPC significantly reduced the amount of bovine serum albumin adsorbed from a solution and proteins adsorbed from brain heart infusion medium compared to the control (P < 0.001). A similar pattern was observed for bacterial adhesion: significantly less Streptococcus mutans cells adhered on the surface of LCFV with 1.5, 3, or 5 wt% MPC (P < 0.001) than on the control, and similar results were obtained for Actinomyces naeslundii and Streptococcus sanguinis adherence to LCFV with 3 wt% MPC. Finally, bacterial adhesion, surface microhardness loss, and the depth of demineralization were substantially lower on bovine tooth enamel surface coated with LCFV containing 3 wt% of MPC than in the control treatment (0 wt% MPC). Therefore, this novel LCFV containing a low concentration of MPC (e.g., 3 wt%) would be effective in anti-biofouling while maintaining the important advantageous features of light-curable fluoride in preventing demineralization.

Actinomyces and Alimentary Tract Diseases: A Review of Its Biological Functions and Pathology.

Actinomyces are nonmotile, filamentous, Gram-positive bacteria that cause actinomycosis in immunodeficiency patients. Although the prognosis of actinomycosis is good, the diagnosis of actinomycosis is quite difficult. Recent studies on actinomycosis have shown that Actinomyces play an important role in various biological and clinical processes, such as the formation of dental plaque and the degradation of organics in the gastrointestinal tract. Here, the distribution of Actinomyces in the digestive tract, and different biological effects of actinomycosis, and its clinical association with inflammatory diseases are discussed. Furthermore, an overview of the most commonly used treatment methods and drugs used to treat Actinomyces infected alimentary canal diseases is presented.

Antibacterial Effect of Silver Diammine Fluoride on Cariogenic Organisms

AIM: To screen the possible antimicrobial activity of a range of clinically used, silver-based compounds on cariogenic organisms: silver diammine fluoride (SDF), silver fluoride, and silver nitrate. MATERIALS AND METHODS: Preliminary screening disk-diffusion susceptibility tests were conducted on Mueller-Hinton agar plates inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces naeslundii, organisms known to be cariogenic. In order to identify which component of the silver compounds was responsible for any antibacterial (AB) effect, and to provide controls, the following were also investigated at high and low concentrations: sodium fluoride, ammonium fluoride, ammonium chloride, sodium fluoride, sodium chloride, and sodium nitrate, as well as deionized water as control. A volume of 10 pL of a test solution was dispensed onto a paper disk resting on the inoculated agar surface, and the plate incubated anaerobically at 37°C for 48 hours. The zones of inhibition were then measured. RESULTS: Silver diammine fluoride, silver fluoride, silver nitrate, and ammonium fluoride had significant AB effect (p < 0.05) on all three test organisms, although ammonium fluoride had no effect at low concentration; the remaining other compounds had no effect. CONCLUSION: Silver ions appear to be the principal AB agent at both high and low concentration; fluoride ions only have an AB effect at high concentration, while ammonium, nitrate, chloride and sodium ions have none. The anticaries effect of topical silver solutions appears restricted to that of the silver ions. CLINICAL SIGNIFICANCE: Silver compounds, such as SDF, silver fluoride, and silver nitrate have AB effect against cariogenic organisms and these may have clinical impact in arresting or preventing dental decay. Sodium fluoride did not have AB effect under the conditions tested.

Actinomyces cavernous sinus infection: a case and systematic literature review.

A 63-year-old man presented with a 2-month history of progressive right-sided exophthalmos, painful ophthalmoplegia and fevers. As more features developed, he was diagnosed with giant cell arteritis, then Tolosa-Hunt syndrome, and transiently responded to corticosteroids. A bland cerebrospinal fluid and highly metabolically active brain (18F)-fluoro-D-glucose-positron emission tomography suggested lymphoma. Biopsy of the mass showed sulphur granules with Gram-positive filamentous bacteria with Actinomyces-like colonies. Actinomyces cavernous sinus infections are rare and indolent. They often mimic non-infective causes including other inflammatory and infiltrative conditions, vascular and neoplastic causes, particularly lymphoma. Clinicians should consider infective cavernous sinus syndromes in people with a fluctuating painful ophthalmoplegia that responds poorly to corticosteroids. The term Tolosa-Hunt syndrome is problematic and should be retired or used only with reservation.

Case Report: Iatrogenic Infection from Traditional Treatment of Stingray Envenomation.

A 47-year-old man was stung on the left ankle by a stingray while on vacation on the Island of Bubaque, Guinea-Bissau. The affected limb was initially treated with an attempt to suck out the venom and application of chewed plant root. The following 3 days, local pain gradually diminished, but then high fever erupted together with generalized symptoms and intense pain from the ankle. After initiating antibiotic treatment, the patient was evacuated. Because of sustained symptoms and fever, the wound was surgically debrided, and culture revealed infection with oral flora bacteria. Attempts to suck out venom are not recommended.

Pelvic actinomycosis and IUD.

OBJECTIVE: To summarize knowledge about the mana-gement in women with proven actinomyces in uterine cervix and inserted intrauterine device (IUD). DESIGN: An overall review. RESULTS: Actinomycosis is an uncommon but important subacute or chronic infection caused by anaerobic or microaerophilic bacteria, mainly within the Actinomyces genus. Actinomycosis can affect various organs and tissues in the human body, often manifesting draining sinuses, abscess formation and fibrosis. The pelvic form in women is the most common in the developed countries. Long-duration treatment with antibiotics can be completely effective even in cases of heavy disease. Although pelvic actinomycosis is predominantly associated with the longstanding use of intrauterine device, the risk of future symptomatic infection is extremly low even in women with a cervical Pap smear positive for actinomyces-like organisms (ALO). Therefore the identification of actinomycetes by cytology after cervical Pap smears is not diagnostic nor predictive of any disease because the actinomycetes normally reside in the female genital tract. In the absence of symptoms, patients with ALO on a Pap test do not need antimicrobial treatment or IUD removal. Nevertheless, women choosing an IUD for contraception should know that there is very low risk of developing the infection in later years after insertion. CONCLUSION: The sources of literature conclude that removal of the intrauterine device in a patients with a positive ALO in the uterine cervix is not necessary and antibiotics treatment is not required. However, IUD must be changed at least every five years in order to limit the risk of the development of pelvic actinomycosis.

The cytopathology of Actinomyces, Nocardia, and their mimickers.

Nocardia species and Actinomyces species are 2 of the most commonly diagnosed filamentous bacteria in routine cytopathology practice. These genera share many overlapping cytomorphologic features, including their thin, beaded, branching, Gram-positive, GMS-positive filamentous structures that fragment at their peripheries into bacillary- and coccoid-appearing forms. Features that help distinguish between these 2 microorganisms include the width of their filamentous structures, the angles at which they branch, and their ability or lack thereof to retain a modified acid-fast stain. In addition to cytomorphologic overlap, overlap in clinical presentation is frequent with pulmonary and mucocutaneous presentations seen in both. Differentiating between Nocardia and Actinomyces is essential because patients with these infections require different approaches to medical management. Both antibiotic susceptibilities and the need for early surgical intervention as part of the treatment plan vary greatly among these 2 groups. This review focuses on the clinical presentation, cytomorphology and staining characteristics that can be useful in identifying and distinguishing between Nocardia and Actinomyces infections, as well as their mimickers.

Actinomyces-Related Tubo-Ovarian Abscess in a Poorly Controlled Type II Diabetic With a Copper Intrauterine Device.

BACKGROUND: The historic association of Actinomyces israelii infection with intrauterine devices (IUDs) has long been recognized. In recent years, the risk of developing pelvic inflammatory disease with a copper or levonorgestrel IUD has been less than 1% in women who are low risk for sexually transmitted infections. IUD-related pelvic infections secondary to actinomyces have largely vanished from contemporary practice. CASE: A 49-year-old using a copper IUD for contraception with poorly controlled type II diabetes mellitus was admitted for suspected tubo-ovarian abscess on the basis of abdominopelvic pain, leukocytosis, and computed tomography findings. After she was treated with intravenous and outpatient antibiotics with clinical improvement, repeat imaging 1 month later revealed a persistent complex left adnexal mass. Tumor markers were negative but given the persistence and complex nature of the mass, surgical management was recommended. A robotic-assisted hysterectomy with bilateral salpingo-oophorectomy was performed. Adhesiolysis, profuse irrigation, and ureteral stenting were required. Pathology revealed bilateral tubo-ovarian abscesses with actinomyces species identified on intraoperative culture. The patient had a total of 10 days of postoperative antibiotics and improved glucose control with no further signs of infection. CONCLUSION: Although actinomyces-related IUD PID is considered an outdated diagnosis, there are intermittent case reports of bizarre presentations in older women, often mimicking malignancy. Actinomyces should be a consideration in tubo-ovarian abscesses or pelvic inflammatory disease in patients with an IUD in place, particularly those who have poor glucose control or are otherwise immunosuppressed. Early identification and treatment of actinomyces tubo-ovarian abscesses may reduce surgical morbidity and overall improve patient outcomes and safety.

Comparative evaluation of MicroDTTect device and flocked swabs in the diagnosis of prosthetic and orthopaedic infections.

The evolution of new prosthetic and osteosynthetic devices has led to more surgical indications, and this is accompanied by an increased incidence of septic complications in orthopaedic and trauma surgery in the general population. The strategy for choosing surgical or therapeutic (conservative) treatment is based on the identification of the pathogen: knowledge of the aetiological agents is an essential element in the decision-making process to ensure the most effective treatment is administered. The pathogen also needs to be considered in the challenging case of doubtful infection, where perhaps the only sign is inflammation, for a more accurate prediction of progression to either sepsis or healing. Biofilm-related infections and low-grade infections may fall into this category. Biofilm slows the metabolism of microorganisms and prolongs their survival, which renders them resistant to antibiotics. Moreover, when microorganisms are embedded in the biofilm they are poorly recognised by the immune system and the infection becomes chronic. As recently demonstrated, isolation and identification of bacteria in biofilm is difficult as the bacteria are concealed. The development of an effective means of sample collection and laboratory methods that can dislodge bacteria from prosthetic surfaces has therefore become necessary. The primary aim of the study was to evaluate the reliability of an innovative technology (MicroDTTect), specifically applied to collect and transport explanted samples (prostheses, osteosynthetic devices, biological tissues), and compare with flocked swabs. The MicroDTTect system is quick and simple to use and, most importantly, is a closed system that is totally sterile and safe for the patient being treated. It contains a specific concentration of dithiotreitol (DTT) that can dislodge bacteria from the biofilm adhering to prosthetic surfaces. The numbers of positive and negative samples were measured to compare the MicroDTTect methodology with swab collection in 30 procedures. The results showed that MicroDTTect had a higher sensitivity compared to swabs (77% and 46%, respectively), and was associated with more positive results than swabs (35% and 20%, respectively). These preliminary results show that MicroDTTect is superior to swab collection for bacterial identification in orthopaedic surgery. The early identification of microorganisms that cause sepsis may help improve treatment strategies and the efficacy of therapy, which will lead to an increased healing rate, reduced severity of sequelae and improved quality of life.

Comparative in vitro investigation of the cariogenic potential of bifidobacteria.

OBJECTIVE: This study aimed to assess the in vitro cariogenic potential of some Bifidobacterium species in comparison with caries-associated bacteria. DESIGN: Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium animalis, Bifidobacterium dentium, Lactobacillus acidophilus, Lactobacillus casei, Actinomyces israelii, Streptococcus sobrinus and Streptococcus mutans were tested for acidogenicity and aciduricity by measuring the pH of the cultures after growth in glucose and bacterial growth after exposure to acid solutions. Biofilm biomass was determined for each species either alone or associated with S. mutans or S. mutans/S. sobrinus. Enamel hardness was analyzed before and after 7-days biofilm formation using bacterial combinations. RESULTS: B. animalis and B. longum were the most acidogenic and aciduric strains, comparable to caries-associated bacteria, such as S. mutans and L. casei. All species had a significantly increased biofilm when combined either with S. mutans or with S. mutans/S. sobrinus. The greatest enamel surface loss was produced when B. longum or B. animalis were inoculated with S. mutans, similar to L. casei and S. sobrinus. All strains induced similar enamel demineralization when combined with S. mutans/S. sobrinus, except by B. lactis. CONCLUSION: The ability to produce acidic environments and to enhance biofilm formation leading to increased demineralization may mean that Bifidobacterium species, especially B. animalis and B. longum, are potentially cariogenic.

The association of medication-related osteonecrosis of the jaw with Actinomyces spp. infection.

Medication-related osteonecrosis of the jaw (MRONJ) represents a complication of bisphosphonate treatment that responds poorly to standard treatment. In a retrospective cohort study we investigated a possible role of Actinomyces spp. in the pathogenesis of MRONJ. Deep biopsies of necrotic bone were collected during surgical treatment of MRONJ and evaluated by histology and microbiology for the presence of Actinomyces spp. Microbiological, demographic and clinicpathological data were analyzed for risk of Actinomyces-associated MRONJ. Between 2005 and 2014, 111 patients suffering from histologically-confirmed MRONJ were identified. Actinomyces spp. were detected in 99 cases (89%) by histology and in six further patients by microbiological culture. A diverse microbial flora was found in all specimens without association with Actinomyces spp. Demographic and clinicopathological characteristics did not separate significantly Actinomyces-positive from Actinomyces-negative cases. Our observations confirm previous reports of a high prevalence of Actinomyces spp. in MRONJ in the single largest cohort available up to now. The high prevalence of Actinomyces spp. and the lack of clinicopathological risk factors underline the prominent role of Actinomyces spp. in MRONJ and may change the current understanding of MRONJ. Established prolonged antimicrobial treatment regimens against Actinomyces spp. infection could therefore be a mainstay of future MRONJ management.