Intestinal Bacteria Fluctuating in Early-Stage Colorectal Cancer Carcinogenesis are Associated with Diet in Healthy Adults.

This hospital-based, cross-sectional study aimed to explore the association between diet and fluctuating intestinal bacteria in early-stage colorectal cancer (CRC) (Atopobium parvulum, Actinomyces odontolyticus, Solobacterium moorei, and Bifidobacterium longum). Healthy participants (n = 212) who underwent total colonoscopy at National Cancer Center Hospital (Tokyo, Japan) were divided into two groups according to the relative abundance of bacteria in their feces: those in the top 25% of relative bacterial abundance as cases and the bottom 25% as controls. The participants were divided into three groups (low, medium, and high) according to their intake of food groups associated with CRC. Multivariable logistic regression analysis was conducted to estimate the association between dietary intake and higher relative abundance of bacteria. Dairy products were inversely associated with a higher relative abundance of A. parvulum, A. odontolyticus, and S. moorei, with odds ratios (high vs. low) and 95% confidence interval as follows: 0.16 (0.06-0.44), 0.25 (0.08-0.82), and 0.29 (0.11-0.78), respectively. Additionally, dietary fiber was inversely associated with a higher relative abundance of S.moorei (0.29 [0.11-0.78]). No association was observed between diet and B.longum. In conclusion, healthy adults with a higher intake of dairy products and fiber had lower odds of having a higher relative abundance of CRC-associated microbiota.

Characterization of isolates of members of the genus Actinomyces from Marmota himalayana: description of Actinomyces faecalis sp. nov., Actinomyces respiraculi sp. nov., and Actinomyces trachealis sp. nov.

Six novel strains (ZJ34T, ZJ561, ZJ750T, ZJ1629, zg-993T and zg-987) isolated from faeces and respiratory tracts of Marmota himalayana from the Qinghai-Tibet Plateau of PR China were characterized comprehensively. The results of analyses of the 16S rRNA gene and genome sequences indicated that the six strains represent three novel species of the genus Actinomyces, and are closely related to Actinomyces urogenitalis DSM 15434T (16S rRNA gene sequences similarities, 94.9-98.7 %), Actinomyces weissii CCUG 61299T (95.6-96.6 %), Actinomyces bovis CCTCC AB2010168T (95.7 %) and Actinomyces bowdenii DSM 15435T (95.2-96.4 %), with values of digital DNA-DNA hybridization less than 30.1 % when compared with their closest relatives but higher than 70 % within each pair of novel strains (ZJ34T/ZJ561, ZJ750T/ZJ1629 and zg-993T/zg-987). All the novel strains had C18 : 1 ω9c and C16 : 0 as the two most abundant major fatty acids. MK-9(H4) or MK-8(H4) was the sole or predominant respiratory quinone of strains ZJ34T, ZJ750T and zg-993T and their polar lipid profiles differed, but all had diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidyl inositol mannoside as major components. ZJ750T shared identical peptidoglycan amino acid profile with ZJ34T (alanine, glutamic acid, lysine and ornithine) and the same whole-cell sugar composition with zg-993T (glucose, rhamnose and ribose). Strain zg-993T contained alanine, aspartic acid, glutamic acid, glycine and lysine in the peptidoglycan, and the only sugar in ZJ34T was ribose. The DNA G+C contents of the novel strains were within the range of 65.8-70.1 mol%. On the basis of the results from the aforementioned analyses, the six novel strains were classified as representing three novel species of genus Actinomyces, for which the names Actinomyces faecalis sp. nov. [type strain ZJ34T (=GDMCC 1.1952T=JCM 34355T)], Actinomyces respiraculi sp. nov. [type strain ZJ750T (=GDMCC 1.1950T=JCM 34356T)] and Actinomyces trachealis sp. nov. [type strain zg-993T (=GDMCC 1.1956T=JCM 34357T)] were proposed, respectively.

Kibdelosporangium persicum sp. nov., a new member of the Actinomycetes from a hot desert in Iran.

Isolate 4NS15T was isolated from a neglected arid habitat in Kerman, Iran. The strain showed 16S rRNA gene sequence similarity values of 98.9 % to the type strains of Kibdelosporangium aridum subsp. aridum, Kibdelosporangium phytohabitans and Kibdelosporangium philippinense and 98.6 % to the type strain K. aridum subsp. largum, respectively. Genome-based phylogenetic analysis revealed that isolate 4NS15T is closely related to Kibdelosporangium aridum subsp. aridum DSM 43828T. The digital DNA-DNA hybridization value between the genome sequences of 4NS15T and strain DSM 43828T is 29.8 %. Strain 4NS15T produces long chains of spores without a sporangium-like structure which can be distinguished from other Kibdelosporangium species. Isolate 4NS15T has a genome size of 10.35 Mbp with a G+C content of 68.1 mol%. Whole-cell hydrolysates of isolate 4NS15T are rich in meso-diaminopimelic acid and cell-wall sugars such as arabinose, galactose, glucose and ribose. Major fatty acids (>10 %) are C16 : 0, iso-C16 : 0 and iso-C15 : 0. The phospholipid profile contains diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylhydroxyethanolamine, aminolipid and glycoaminolipid. The predominant menaquinone is MK-9(H4). Based on its phenotypic and genotypic characteristics, isolate 4NS15T (NCCB 100701=CIP 111705=DSM 110728) merits recognition as representing a novel species of the genus Kibdelosporangium, for which the name Kibdelosporangium persicum sp. nov. is proposed.

Rapid evolution of decreased host susceptibility drives a stable relationship between ultrasmall parasite TM7x and its bacterial host.

Around one-quarter of bacterial diversity comprises a single radiation with reduced genomes, known collectively as the Candidate Phyla Radiation. Recently, we coisolated TM7x, an ultrasmall strain of the Candidate Phyla Radiation phylum Saccharibacteria, with its bacterial host Actinomyces odontolyticus strain XH001 from human oral cavity and stably maintained as a coculture. Our current work demonstrates that within the coculture, TM7x cells establish a long-term parasitic association with host cells by infecting only a subset of the population, which stay viable yet exhibit severely inhibited cell division. In contrast, exposure of a naïve A. odontolyticus isolate, XH001n, to TM7x cells leads to high numbers of TM7x cells binding to each host cell, massive host cell death, and a host population crash. However, further passaging reveals that XH001n becomes less susceptible to TM7x over time and enters a long-term stable relationship similar to that of XH001. We show that this reduced susceptibility is driven by rapid host evolution that, in contrast to many forms of phage resistance, offers only partial protection. The result is a stalemate where infected hosts cannot shed their parasites; nevertheless, parasite load is sufficiently low that the host population persists. Finally, we show that TM7x can infect and form stable long-term relationships with other species in a single clade of Actinomyces, displaying a narrow host range. This system serves as a model to understand how parasitic bacteria with reduced genomes such as those of the Candidate Phyla Radiation have persisted with their hosts and ultimately expanded in their diversity.

Actinomyces in Forensic Practice.

ABSTRACT: A 19-year-old woman in septic shock with recent computed tomography findings of a loculated hepatic abscess was transferred to an intensive care unit where she went into asystolic cardiac arrest. After resuscitation, surgical exploration revealed a purulent pericardial effusion with tamponade and a liver abscess. Microbiological analyses from both sites were negative. Shortly after surgical exploration, she developed multiorgan failure and died. At autopsy, pus was observed both within the pericardial cavity and around the left lobe of the liver. Green "sulfur granules" suggestive of infection with Actinomyces spp. were able to be extruded from the liver during the postmortem examination and cultures returned positive for Actinomyces israelii. This case is a rare example of primary hepatic actinomycosis infection that resulted in the death of a young woman. Nonspecific clinical manifestations may delay diagnosis; however, the finding of "sulfur granules" in areas of abscess formation at autopsy should be taken as an indication of possible underlying Actinomyces infection.

Vaginal estrogen therapy is associated with increased Lactobacillus in the urine of postmenopausal women with overactive bladder symptoms.

BACKGROUND: Previous work has shown that the vaginal microbiome decreases in Lactobacillus predominance and becomes more diverse after menopause. It has also been shown that estrogen therapy restores Lactobacillus dominance in the vagina and that topical estrogen is associated with overactive bladder symptom improvement. We now know that the bladder contains a unique microbiome and that increased bladder microbiome diversity is associated with overactive bladder. However, there is no understanding of how quickly each pelvic floor microbiome responds to estrogen or if those changes are associated with symptom improvement. OBJECTIVE: This study aimed to determine if estrogen treatment of postmenopausal women with overactive bladder decreases urobiome diversity. STUDY DESIGN: We analyzed data from postmenopausal participants in 2 trials (NCT02524769 and NCT02835846) who chose vaginal estrogen as the primary overactive bladder treatment and used 0.5 g of conjugated estrogen (Premarin cream; Pfizer, New York City, NY) twice weekly for 12 weeks. Baseline and 12-week follow-up data included the Overactive Bladder questionnaire, and participants provided urine samples via catheter, vaginal swabs, perineal swabs, and voided urine samples. Microbes were detected by an enhanced culture protocol. Linear mixed models were used to estimate microbiome changes over time. Urinary antimicrobial peptide activity was assessed by a bacterial growth inhibition assay and correlated with relative abundance of members of the urobiome. RESULTS: In this study, 12 weeks of estrogen treatment resulted in decreased microbial diversity within the vagina (Shannon, P=.047; Richness, P=.043) but not in the other niches. A significant increase in Lactobacillus was detected in the bladder (P=.037) but not in the vagina (P=.33), perineum (P=.56), or voided urine (P=.28). The change in Lactobacillus levels in the bladder was associated with modest changes in urgency incontinence symptoms (P=.02). The relative abundance of the genus Corynebacterium correlated positively with urinary antimicrobial peptide activity after estrogen treatment. CONCLUSION: Estrogen therapy may change the microbiome of different pelvic floor niches. The vagina begins to decrease in diversity, and the bladder experiences a significant increase in Lactobacillus levels; the latter is correlated with a modest improvement in the symptom severity subscale of the Overactive Bladder questionnaire.

Actinomyces qiguomingii sp. nov., isolated from the Pantholops hodgsonii.

Two previously undescribed, Gram-stain-positive, rod-shaped strains, 410T and 553, were isolated from faeces of the Tibetan antelope (Pantholops hodgsonii) from the Tibet-Qinghai Plateau, PR China. The optimum growth conditions of the two novel strains were 1 % (w/v) NaCl, 37 °C and pH 7. The end products from glucose fermentation included ethanol and lactic acid. Based on results of 16S rRNA gene sequence comparison and phylogenetic and phylogenomic analyses, strains 410T and 553 were classified into the genus Actinomyces, and were closely related to Actinomyces ruminicola (97.6 %), Actinomyces oricola (93.5 %) and Actinomyces dentalis (90.8 %). The genomic G+C content of strain 410T was 67.4 mol%. Digital DNA-DNA hybridization values between strain 410T and each of the closely related species were under 70 %. The respiratory quinones were MK-10 (68 %) and MK-9 (32 %). The main cellular fatty acids of the isolates were C16 : 0, followed by C18 : 1 ω9c. The major polar lipids were diphosphatidylglycerol and phosphatidylinositol-mannoside. The whole-cell sugars contained rhamnose, ribose and glucose. The diagnostic amino acids of cell-wall peptidoglycan included alanine, glutamic acid, lysine and ornithine. The results of biochemical, chemotaxonomic and genotypic analyses revealed that the two novel strains represent a novel species of genus Actinomyces, for which the name Actinomyces qiguomingii sp. nov. is proposed. The type strain is 410T (=CGMCC 1.16361T= DSM 106201T).

Actinomyces wuliandei sp. nov., Corynebacterium liangguodongii sp. nov., Corynebacterium yudongzhengii sp. nov. and Oceanobacillus zhaokaii sp. nov., isolated from faeces of Tibetan antelope in the Qinghai-Tibet plateau of China.

Eight Gram-stain-positive, rod-shaped bacterial strains were isolated from faeces of Tibetan antelopes on the Tibet-Qinghai Plateau of China. Genomic sequence analysis showed that the strains belong to the genera Actinomyces (strains 299T and 340), Corynebacterium (strains 2184T, 2185, 2183T and 2189) and Oceanobacillus (strains 160T and 143), respectively, with a percentage of similarity for the 16S rRNA gene under the species threshold of 98.7 % except for strains 160T and 143 with Oceanobacillus arenosus CAU 1183T (98.8 %). The genome sizes (and genomic G+C contents) were 3.1 Mb (49.4 %), 2.5 Mb (64.9 %), 2.4 Mb (66.1 %) and 4.1 Mb (37.1 %) for the type strains 299T, 2183T, 2184T and 160T, respectively. Two sets of the overall genome relatedness index values between our isolates and their corresponding closely related species were under species thresholds (95 % for average nucleotide identity, and 70 % for digital DNA-DNA hybridization). These results, together with deeper genotypic, genomic, phenotypic and biochemical analyses, indicate that these eight isolates should be classified as representing four novel species. Strain 299T (=CGMCC 1.16320T=JCM 33611T) is proposed as representing Actinomyces wuliandei sp. nov.; strain 2184T (=CGMCC 1.16417T=DSM 106203T) is proposed as representing Corynebacterium liangguodongii sp. nov.; strain 2183T (=CGMCC 1.16416T=DSM 106264T) is proposed as representing Corynebacterium yudongzhengii sp. nov.; and strain 160T (=CGMCC 1.16367T=DSM 106186T) is proposed as representing Oceanobacillus zhaokaii sp. nov.

Measuring the subgingival microbiota in periodontitis patients: Comparison of the surface layer and the underlying layers.

Periodontitis is a major cause of tooth loss in adults that initially results from dental plaque. Subgingival plaque pathogenesis is affected by both community composition and plaque structures, although limited data are available concerning the latter. To bridge this knowledge gap, subgingival plaques were obtained using filter paper (the fourth layer) and curette (the first-third layers) sequentially and the phylogenetic differences between the first-third layers and the fourth layer were characterized by sequencing the V3-V4 regions of 16S rRNA. A total of 11 phyla, 148 genera, and 308 species were obtained by bioinformatic analysis, and no significant differences between the operational taxonomic unit numbers were observed for these groups. In both groups, the most abundant species were Porphyromonas gingivalis and Fusobacterium nucleatum. Actinomyces naeslundii, Streptococcus intermedius, and Prevotella intermedia possessed relatively high proportions in the first-third layers; while in the fourth layer, both traditional pathogens (Treponema denticola and Campylobacter rectus) and novel pathobionts (Eubacterium saphenum, Filifactor alocis, Treponema sp. HOT238) were prominent. Network analysis showed that either of them exhibited a scale-free property and was constructed by two negatively correlated components (the pathogen component and the nonpathogen component), while the synergy in the nonpathogen component was lower in the first-third layers than that in the fourth layer. After merging these two parts into a whole plaque group, the negative/positive correlation ratio increased. With potential connections, the first-third layers and the fourth layer showed characteristic key nodes in bacterial networks.

A rare case of brain abscess caused by Actinomyces meyeri.

BACKGROUND: Brain abscesses are the rare and most severe form of actinomycosis, which usually manifests as abscesses of the occipital or parietal lobe due to direct expansion from an adjacent area, the oral cavity. In the medical literature, there are only a few reported cases of brain abscess caused by Actinomyces meyeri. In this report, we present a 35-year-old male patient who experienced an insidious headache and left-sided weakness and was diagnosed with an Actinomyces meyeri brain abscess. CASE PRESENTATION: A 35-year-old Nepalese man came to our institute with the primary complaint of insidious onset of headache and left-sided weakness. His physical examination was remarkable for the left-sided weakness with power 2/5 on both upper and lower limbs, hypertonia, hyperreflexia and positive Babinski sign, with intact sensory function. Cardiac examination revealed systolic murmur with regular S1 and S2, and lung examination was normal. The patient had poor dental hygiene. Biochemistry and haematology panel were normal. Urinalysis, chest X-ray and electrocardiogram revealed no abnormality. A transthoracic echocardiogram revealed mitral regurgitation. However, there was no evidence of valvular vegetation. A magnetic resonance imaging (MRI) of the brain was performed, which showed a bi-lobed rim enhancing lesion with a conglomeration of two adjoining round lesions in the right parietal parasagittal region. Perilesional oedema resulting in mass effect over the right lateral ventricle and mid-right uncal herniation with midline shift was noted. Craniotomy was performed, and the lesion was excised. Gram staining of the extracted sample revealed gram variable filamentous rods. Creamy white, moist, confluent colonies were observed after performing anaerobic culture in chocolate agar. On the gram staining, they showed gram-positive filamentous rods. Actinomyces meyeri was identified based on matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology. Based on the susceptibilities, he was successfully treated with ampicillin-sulbactam. CONCLUSIONS: In conclusion, Actinomyces should be considered in the differential diagnosis of brain abscess in patients with poor dental hygiene, and early diagnosis and appropriate treatment can lead to better results.

[Our experiences with Actinomyces urogenitalis in human clinical samples].

Actinomyces urogenitalis is most commonly associated with the human genitourinary system, often only as the resident flora. Outside the genitourinary tract, A. urogenitalis is isolated rather sporadically. Presented are two brief case reports of human infections outside the genitourinary tract as well as experiences with microbiological identification of this actinomycete. Antibiotic susceptibility testing of actinomycetes is focused especially on their resistance to lincosamides and fluoroquinolones. The etiological relationship with the patients' clinical problems was not investigated. Previously reported cases of infections outside the genitourinary tract are also mentioned in the article. The article may aid in expanding the knowledge of the occurrence, diagnosis and susceptibility of A. urogenitalis to antibiotics, particularly in rarely reported extra-genitourinary infections caused by this species. Accurate species identification in routine laboratory practice is important both for determination of the etiological role of the microorganism and for more precise selection of empirical antibiotic therapy.

High-resolution novel method for tracking bacteria in a multi-species biofilm.

The aim of this study is to establish a novel high resolution tracking ability of a specific bacterium in multispecies biofilm. A periodontal multispecies biofilm was constructed with Streptococcus sanguis, Actinomyces naeslundii, Porphyromonas gingivalis and Fusobacterium nucleatum. A single species was stained with fluorescein isothiocyanate (FITC). The mature biofilm was stained for viability (propidium iodide) and analysis was performed with flow cytometry. The sensitivity of the assay was compared with colony forming units (CFU) counts. A single cell suspension of P. gingivalis was grown in broth and biofilm to identify the location of these events on side scatter and forward scatter. The sensitivity of the assay was comparable to that of the CFU counts. The assay allows quantification of the ratio of a single bacterium within the biofilm, and its viable proportion. The described method is reproducible and of high resolution, and allows the examination of microbes' composition and viability within a biofilm structure.

Actinomyces lilanjuaniae sp. nov., isolated from the faeces of Tibetan antelope (Pantholops hodgsonii) on the Qinghai-Tibet Plateau.

Two novel, Gram-stain-positive, non-motile, facultatively anaerobic, rod-shaped bacteria (strains 2129T and 2119) were isolated from the faeces of Tibetan antelopes (Pantholops hodgsonii) on the Qinghai-Tibet Plateau, PR China. The 16S rRNA gene sequences of the strains showed highest similarity values to Actinomyces timonensis DSM 23838T (92.9 and 92.8 %, respectively), and phylogenetic analysis based on 16S rRNA gene and genomic sequences indicated that strains 2129T and 2119 represent a new lineage. Strains 2129T and 2119 could ferment d-adonitol and d-xylose, but were unable to utilize d-mannose and d-melibiose nor produce esterase (C4) and proline arylamidase. The G+C contents of the two strains were both 69.0 mol%. Their genomes exhibited less than 40.4 % relatedness in DNA-DNA hybridization tests (below 70 % as the recommended threshold for new species) with all available genomes of the genus Actinomyces in the NCBI database. The major fatty acids of the two strains were C18 : 1ω9c and C16 : 0, and the major polar lipids were diphosphatidylglycerol, glycolipid, phosphatidylinositol, phosphatidyl inositol mannoside and phosphoglycolipid. Based on the results of genotypic, phenotypic and biochemical analyses, it is proposed that the two unidentified bacteria be classified as representing a novel species, Actinomyces lilanjuaniae sp. nov. The type strain is 2129T (=CGMCC 4.7483T=DSM 106426T).

Actinomyces spp. bloodstream and deep vein thrombus infections in people who inject drugs.

INTRODUCTION: Actinomyces spp. cause several well-described syndromes including cervicofacial and pelvic infections. Actinomyces spp. infection as an opportunistic infection among people who inject drugs has rarely been described with few case reports published. METHODS AND RESULTS: Here we describe four people who inject drugs admitted with Actinomyces spp. infections, all with an overlapping syndrome and who presented a challenge to both diagnose and to manage. DISCUSSION: This case series highlights the potential to overlook Actinomyces spp. infection in people who inject drugs and aims to increase clinician awareness of diagnosis, empirical and directed treatment, and potential complications of this infection.

Actinomycotic Endometritis.

Seven cases of actinomycotic endometritis were identified among 28,906 endometrial biopsies performed in the last 10 yr. The patients' ages ranged from 44 to 85 yr old. An intrauterine device was in place from 7 to 44 yr. The reasons to perform the biopsies included abnormal uterine bleeding, malodor, prolapse, pelvic inflammatory disease, and suspicion of metastatic uterine sarcoma. Definitive identification of Actinomyces israelii by culture was obtained in 1 case only. Gram, Gomori methenamine silver, and Fite stains were useful in the differential diagnosis with pseudoactinomycotic granules, Nocardia, fungi, and other bacteria. The Actinomyces-like organisms were surrounded by extensive suppurative reaction in all cases. The tissues showed florid neutrophilic and plasmacytic inflammation. The treatment consisted of intrauterine device removal and 10 to 30 d of antibiotics in 4 patients. The Actinomyces-like organisms persisted for 6 wk in spite of antibiotic therapy when the intrauterine device removal was delayed in one of those cases. Two patients had hysterectomy and salpingo-oophorectomy due to tubo-ovarian abscess and hysterectomy, salpingo-oophorectomy, and rectosigmoid excision due to pelvic abscess and septic emboli, both followed by 30 to 45 d of antibiotic therapy. One patient had hysterectomy not followed by antibiotics due to prolapse. No other pelvic abscesses were identified on follow-up, which ranged from 4 to 101 mo (median, 20 mo; mean, 44 mo).

Actinomyces neuii: a case report of a rare cause of acute infective endocarditis and literature review.

BACKGROUND: Infective endocarditis caused by Actinomyces spp. is extremely rare. However, cases by new species of Actinomyces have been increasingly reported due to advances in laboratory techniques, and many of these species do not cause classic presentations of actinomycosis. Actinomyces neuii is reported to have a tendency to cause endovascular infection. The course of infective endocarditis caused by Actinomyces spp. is usually indolent. CASE PRESENTATION: A 61-year-old man with history of infective endocarditis, end stage renal disease, and monoclonal gammopathy was admitted for an abrupt fever, confusion, dysarthria, and facial droop after hemodialysis. Echocardiogram showed vegetations on both the aortic and mitral valves. Two sets of blood culture grew A. neuii. Brain MRI showed multiple bilateral cerebral infarcts consistent with septic emboli. The patient recovered after valvular surgery and prolonged intravenous and oral antibiotic therapy. CONCLUSIONS: This case illustrates an unusually acute presentation of A. neuii infective endocarditis. As with other Gram-positive bacilli, Actinomyces spp. isolates are often regarded as a result of contamination. One should keep it in mind as a cause of infective endocarditis in vulnerable patient populations.

Actinomycotic osteomyelitis of a long bone in an immunocompetent adult: a case report and literature review.

BACKGROUND: Actinomycosis is a rare, chronic granulomatous disease caused by Gram-positive anaerobic bacteria that colonize the oral cavity. Cervicofacial actinomycosis is the most frequent clinical presentation of actinomycosis, but hematogenous osteomyelitis at distant sites can occur in rare instance in immunocompromised or pediatric patients, only a few cases have been reported in healthy patients. Here we described a new case of distal femur osteomyelitis caused by Actinomyces in an adult patient who was immunocompetent and had no predisposing factors. CASE PRESENTATION: A woman aged 52 years with no history of trauma presented with severe pain, swelling, and increased local heat in the proximal area of the right knee 3 weeks after she first noticed discomfort. Magnetic resonance imaging showed persistent osteomyelitis of the distal metaphysis and diaphysis of the femur with a multifocal intraosseous abscess pocket. An incision and drainage of the abscess were conducted. The tissue culture, fungus culture, acid fast bacillus (AFB) culture, AFB smear, and tuberculosis polymerase chain reaction test results were negative. A pathologic examination confirmed the presence of actinomycosis. The patient was successfully treated with intravenous penicillin G for 8 weeks followed by oral amoxicillin-clavulanate for 6 weeks with repeated surgical debridement and drainage. After a 5-year follow up, the patient had no signs of recurring infection or complications and she had full range of movement in the affected knee. CONCLUSIONS: Although rare, actinomycotic osteomyelitis can occur in healthy people. Furthermore, actinomycotic osteomyelitis is easily misdiagnosed as tuberculosis in areas with a high prevalence of tuberculosis. To detect and identify the bacteria accurately, pathologic examination should be performed as well as culture tests, because the probability for culture confirmation of actinomycosis is quite low. The initial treatment is vital to a successful outcome without ostectomy or amputation.

A Linear Plasmid-Like Prophage of Actinomyces odontolyticus Promotes Biofilm Assembly.

The human oral cavity is home to a large number of bacteria and bacteriophages (phages). However, the biology of oral phages as members of the human microbiome is not well understood. Recently, we isolated Actinomyces odontolyticus subsp. actinosynbacter strain XH001 from the human oral cavity, and genomic analysis revealed the presence of an intact prophage named xhp1. Here, we demonstrated that xhp1 is a linear plasmid-like prophage, which is a newly identified phage of A. odontolyticus The prophage xhp1 genome is a 35-kb linear double-stranded DNA with 10-bp single-stranded, 3' cohesive ends. xhp1 exists extrachromosomally, with an estimated copy number of 5. Annotation of xhp1 revealed 54 open reading frames, while phylogenetic analysis suggests that it has limited similarity with other phages. xhp1 phage particles can be induced by mitomycin C and belong to the Siphoviridae family, according to transmission electron microscopic examination. The released xhp1 particles can reinfect the xhp1-cured XH001 strain and result in tiny blurry plaques. Moreover, xhp1 promotes XH001 biofilm formation through spontaneous induction and the release of host extracellular DNA (eDNA). In conclusion, we identified a linear plasmid-like prophage of A. odontolyticus, which enhances bacterial host biofilm assembly and could be beneficial to the host for its persistence in the oral cavity.IMPORTANCE The biology of phages as members of the human oral microbiome is understudied. Here, we report the characterization of xhp1, a novel linear plasmid-like prophage identified from a human oral isolate, Actinomyces odontolyticus subsp. actinosynbacter strain XH001. xhp1 can be induced and reinfect xhp1-cured XH001. The spontaneous induction of xhp1 leads to the lysis of a subpopulation of bacterial hosts and the release of eDNA that promotes biofilm assembly, thus potentially contributing to the persistence of A. odontolyticus within the oral cavity.

Actinomyces tangfeifanii sp. nov., isolated from the vulture Aegypius monachus.

A novel, Gram-stain-positive, catalase-positive, non-spore-forming, short rod-shaped strain (VUL4_3T) was isolated from rectal swabs of Old World vultures (Aegypius monachus) from the Tibet-Qinghai Plateau, China. Based on the results of biochemical tests and 16S rRNA gene sequence comparison, strain VUL4_3T was determined to be a member of the genus Actinomyces that is closely related to the type strains of Actinomyces liubingyangii (97.7 % 16S rRNA gene sequence similarity) and Actinomyces marimammalium (96.5 %). Optimal growth occurred at 37 °C, pH 6-7 and with 1 % (w/v) NaCl. The typical major cellular fatty acids of strain VUL4_3T were C18 : 1ω9c, C16 : 0 and C18 : 0. The VUL4_3T genome contained 2 207 832 bp with an average G+C content of 51.9 mol%. DNA-DNA hybridization values between strain VUL4_3T and the above two species of the genus Actinomyces showed less than 32 % DNA-DNA relatedness, supporting a novel species status of strain VUL4_3T. Based on the phenotypic data and phylogenetic inference, the novel species Actinomycestangfeifanii sp. nov. is proposed. The type strain is VUL4_3T (=CGMCC 4.7369T=DSM 103436T).