Analysis of the factors affecting the formation of the microbiome associated with chronic osteomyelitis of the jaw

Predictors for prolonged and escalated perioperative antibiotic therapy after microvascular head and neck reconstruction: a comprehensive analysis of 446 cases

Literature suggests that intravenous prophylaxis exceeding 48 h offers no additional benefit in preventing surgical site infections (SSI) in patients with microvascular head and neck reconstruction. However, protocols for antibiotic therapy duration post-reconstruction are not standardized. This study identifies factors predicting prolonged intravenous antibiotic use and antibiotic escalation in patients receiving free flap head neck reconstruction. A retrospective analysis of 446 patients receiving free flap reconstruction was conducted, examining predictors for antibiotic therapy > 10 days and postoperative escalation. 111 patients (24.8%) experienced escalation, while 159 patients (35.6%) received prolonged therapy. Multivariate regression analysis revealed predictors for escalation: microvascular bone reconstruction (p = 0.008, OR = 2.0), clinically suspected SSI (p < 0.001, OR = 5.4), culture-positive SSI (p = 0.03, OR = 2.9), extended ICU stay (p = 0.01, OR = 1.1) and hospital-acquired pneumonia (p = 0.01, OR = 5.9). Prolonged therapy was associated with bone reconstruction (p = 0.06, OR = 2.0), preoperative irradiation (p = 0.001, OR = 1.9) and culture-positive SSI (p < 0.001, OR = 3.5). The study concludes that SSIs are a primary factor driving the escalation of perioperative antibiotic use. Clinical suspicion of infection often necessitates escalation, even in the absence of confirmed microbiological evidence. Microvascular bone reconstruction was a significant predictor for both the escalation and extension of antibiotic therapy beyond 10 days. Furthermore, preoperative radiation therapy, hospital-acquired pneumonia, and prolonged ICU stay were associated with an increased likelihood of escalation, resulting in significantly extended antibiotic administration during hospitalization. Antibiotic stewardship programmes must be implemented to reduce postoperative antibiotic administration time.Trial registration The study was registered approved by the local Ethics Committee (Nr: 18-1131-104).

Shotgun metagenomic analysis of saliva microbiome suggests Mogibacterium as a factor associated with chronic bacterial osteomyelitis

Osteomyelitis of the jaw is a severe inflammatory disorder that affects bones, and it is categorized into two main types: chronic bacterial and nonbacterial osteomyelitis. Although previous studies have investigated the association between these diseases and the oral microbiome, the specific taxa associated with each disease remain unknown. In this study, we conducted shotgun metagenome sequencing (≥10 Gb from ≥66,395,670 reads per sample) of bulk DNA extracted from saliva obtained from patients with chronic bacterial osteomyelitis (N = 5) and chronic nonbacterial osteomyelitis (N = 10). We then compared the taxonomic composition of the metagenome in terms of both taxonomic and sequence abundances with that of healthy controls (N = 5). Taxonomic profiling revealed a statistically significant increase in both the taxonomic and sequence abundance of Mogibacterium in cases of chronic bacterial osteomyelitis; however, such enrichment was not observed in chronic nonbacterial osteomyelitis. We also compared a previously reported core saliva microbiome (59 genera) with our data and found that out of the 74 genera detected in this study, 47 (including Mogibacterium) were not included in the previous meta-analysis. Additionally, we analyzed a core-genome tree of Mogibacterium from chronic bacterial osteomyelitis and healthy control samples along with a reference complete genome and found that Mogibacterium from both groups was indistinguishable at the core-genome and pan-genome levels. Although limited by the small sample size, our study provides novel evidence of a significant increase in Mogibacterium abundance in the chronic bacterial osteomyelitis group. Moreover, our study presents a comparative analysis of the taxonomic and sequence abundances of all genera detected using deep salivary shotgun metagenome data. The distinct enrichment of Mogibacterium suggests its potential as a marker to distinguish between patients with chronic nonbacterial osteomyelitis and chronic bacterial osteomyelitis, particularly at the early stages when differences are unclear.

Microbial Profiles in Oral Lichen Planus: Comparisons with Healthy Controls and Erosive vs. Non-Erosive Subtypes

Recent studies have begun exploring the potential involvement of microbiota in the pathogenesis of oral lichen planus (OLP), yet comprehensive investigations remain limited. Hence, this study aimed to compare the microbial profiles in saliva samples obtained from patients with OLP against those from healthy controls (HC), along with a comparison between erosive (E) and non-erosive (NE) OLP patients. Saliva samples were collected from 60 OLP patients (E: n = 25, NE: n = 35) and 30 HC individuals. Analysis revealed no significant differences in alpha diversity, as assessed by the Chao1 and Shannon index, across the three groups. However, Bray-Curtis distance analysis indicated a significant disparity in microbiome composition distribution between HC and E-OLP, as well as HC and NE-OLP groups. The six most abundant phyla observed across the groups were Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, Fusobacteria, and Saccharibacteria (TM7). Notably, OLP groups exhibited a higher prevalence of Bacteroidetes. Prevotella emerged as the predominant genus in the OLP groups, while Capnocytophaga showed a relatively higher prevalence in E-OLP compared to NE-OLP. This study's findings indicate a notable difference in microbiota composition between HC and patients with OLP. Additionally, differences in the microbiome were identified between the E-OLP and NE-OLP groups. The increase in the proportion of certain bacterial species in the oral microbiome suggests that they may exacerbate the inflammatory response and act as antigens for OLP.

Can jaw bone healed from chronic sclerosing osteomyelitis be considered healthy when planning dental implants? Case report with 20-year follow-up

Introduction and importance

Extraction of mandibular third molars can lead to complications such as chronic sclerosing osteomyelitis (CSO), an inflammatory bone marrow disease that tends to progress. CSO involves the cortical plates and often the periosteal tissues and is caused by a variety of microorganisms, including Corynebacterium spp. The treatment of chronic osteomyelitis (CO) and CSO remains challenging, as there is no universal treatment protocol. This case report investigated whether jaw bone that has healed from chronic sclerosing osteomyelitis can be considered healthy bone when planning dental implants.

Case presentation

A 21-year-old Caucasian woman developed CO and CSO after third molar surgery.

Clinical discussion

A combination of alveolar ridge bone resection, extraction of teeth 47-32, and long-term specific antibiotic therapy against Corynebacterium spp. was administered. An attempt at preprosthetic alveolar ridge reconstruction with an anterior superior iliac crest bone graft resulted in graft failure and the patient refused further harvesting procedures. Implantation in the intraforaminal zone also resulted in the loss of two implants after loading. Finally, inferior alveolar nerve transposition resulted in the successful reimplantation of two implants, which were fully functional almost 11 years later.

Conclusion

This case report presents the treatment history of this patient. With a longitudinal observation period of greater than 20 years, the results of this case demonstrate the successful treatment of bone with CO, CSO, and Corynebacterium spp. infection. Following the removal of infected bone, radical debridement, and long-term antibiotic therapy, bone health was restored.

Innovative biochemisurgical treatment for stabilisation of an end-stage chronic wound in a complex vascular compromized patient

INTRODUCTION

Treating advanced peripheral arterial occlusive disease (e.g. PAOD IV) poses a significant challenge, as conventional treatments quite often fall short at this stage. However, a range of interventions can be considered to postpone amputation. This study presents an example of advanced stage of Peripheral Artery Occlusive Disease (PAOD) stage IV, encompassing a history of a high thigh amputation on the left side, coupled with pronounced wound healing disorders.

PRESENTATION OF CASE

Our patient, 55 years old, smoker and ASA Class III is in a left sided above-the knee-amputation situation. He presented to our outpatient clinic with blistering in the stump area, caused by non-proportinate pressure from the prosthesis. With an emerging septic course and advanced peripheral arterial occlusive disease (PAOD) at Fontaine class IV, revascularization was unfeasible in the left iliac artery axis and groin arteries. Additionally, a stage PAOD IV presents itself with poorly healing wounds on the right side which our patient still uses to support his transfers in and out bed and his wheelchair. Multiple surgical stump revisions and femur shortenings and diverse wound treatments were performed all were unsatisfying for patient and practitioners. We introduced a novel biochemisurgical treatment in our teaching hospital.

DISCUSSION

Desiccating-agent-A is an innovative dehydrating agent with potent desiccating characteristics upon application to organic substances. Its formulation involves blending 83% methane sulfonic acid with proton acceptors and dimethyl sulfoxide, as outlined in patent application. The case description results in an illustrated follow up period of 16 months and is presented in line with the recommendations of the consensus-based surgical case reporting guideline development.

CONCLUSION

The goal of achieving a secondary healing trend is to establish stability within the wound area or achieve complete healing. This endeavor becomes particularly intricate when severe blood circulation compromise exists. Nonetheless, progress in wound treatment measures has made it feasible to achieve this aim by fostering the formation of dry and clean necrotic tissue. This dry and clean wound is now manageable in a patient's home situation, allowing for effective care and a better chance at preventing further severe complications.

Chronic mandibular osteomyelitis associated with a novel probable Kocuria sp in a sugar glider (Petaurus breviceps)

Dental disease in sugar gliders (Petaurus breviceps) is understudied, with only limited clinical and pathological data available. An approximately 7-year-old female sugar glider presented to its primary care veterinarian for a decline in food intake, rapid weight loss and a mass involving the rostral mandible. At necropsy, the mandibular mass effaced most of the rostral mandible and adjacent musculature. Histologically, the mandible was disrupted by nodular infiltrates of variably degenerate neutrophils and macrophages encased in granulomatous inflammation and fibrous connective tissue. Within the neutrophilic cell population were segments of fragmented, necrotic bone and cloud-like colonies of gram-positive cocci. Aerobic culture yielded a heavy, pure growth of a gram-positive coccus morphologically consistent with those identified in the lesions, which was identified as a presumptively novel Kocuria sp by polymerase chain reaction and sequencing of the 16S rRNA gene. This is the first description of Kocuria infection in association with clinically significant pathology in an animal. Although isolated as a pure growth, Kocuria sp cannot be confirmed as the sole cause of lesion formation due to the case chronicity and potential for unculturable, polymicrobial infections. This report adds to our understanding of the clinical and pathological aspects of dental disease in sugar gliders.

Oral microbiota may affect osteoradionecrosis following radiotherapy for head and neck cancer

BACKGROUND

Osteoradionecrosis (ORN) is a serious complication of radiotherapy for head and neck cancer (HNC). However, its etiology and pathogenesis have not been completely elucidated. Recent studies suggest the involvement of the oral microbiota in the development of ORN. The aim of this study was to assess the correlation between oral microbiota and the extent of bone resorption in ORN patients.

MATERIALS AND METHODS

Thirty patients who received high-dose radiotherapy for HNC were enrolled. Tissue specimens were collected from the unaffected and affected sides. The diversity, species differences and marker species of the oral microbial community were determined by 16 S rRNA sequencing and bioinformatics analysis.

RESULTS

The ORN group had greater microbial abundance and species diversity. The relative abundance of f_Prevotellaceaeand, f_Fusobacteriaceae, f_Porphyromonadaceae, f_Actinomycetaceae, f_Staphylococcaceae, g_Prevotella, g_Staphylococcus, s_Endodontalis and s_Intermedia were particular;y increased in ORN, suggesting a potential association between the oral microbiota and ORN. Furthermore, g_Prevotella, g_Streptococcus, s_parvula and s_mucilaginosa were identified as potential diagnostic and prognostic biomarkers of ORN. Association network analysis also suggested an overall imbalance in species diversity and ecological diversity in the oral microbiota of ORN patients. In addition, pathway analysis indicated that the dominant microbiota in ORN may disrupt bone regeneration by regulating specific metabolic pathways that increase osteoclastic activity.

CONCLUSION

Radiation-induced ORN is associated with significant changes in the oral microbiota, and the latter may play a potential role in the etiopathology of post-radiation ORN. The exact mechanisms through which the oral microbiota influence osteogenesis and osteoclastogenesis remain to be elucidated.

Disproportionate responses between free-living and particle-attached bacteria during the transition to oxygen-deficient zones in the Bohai Seawater

The Bohai Sea has recently suffered several seasonal oxygen-deficiency, even hypoxia events during the summer. To better understand effects of dissolved oxygen (DO) concentration on the bacterial composition in particle attached (PA) and free living (FL) fractions during the transition from oxic water to low oxygen conditions, the bacterial communities under three different oxygen levels, i.e., high oxygen (HO, close to 100% O₂ saturation), medium oxygen (MO, close to 75% O₂ saturation), and low oxygen (LO, close to 50% O₂ saturation) in the Bohai Sea were investigated using 16S rRNA amplicon sequencing. Fourteen water samples from 5 stations were collected during a cruise from August to September in 2018. The results showed that the sequences of Proteobacteria and Actinobacteriota jointly accounted for up to 74% across all 14 samples. The Shannon index in HO samples were significantly higher than in LO samples (P < 0.05), especially in PA communities. The composition of bacterial communities varied by oxygen concentration in all samples, and the effect was more pronounced in the PA fraction, which indicates that the PA fraction was more sensitive to the change in oxygen concentration, possibly due to the tighter interactions in this community than in the FL fraction. This study provides novel insights into the distribution of bacterial communities, and clues for understanding the responses of bacterial communities in the Bohai Sea during the transition from the oxic to oxygen-deficient zones.

Impact of the Host-Microbiome on Osteomyelitis Pathogenesis

The microbiome is a collection of genomes from microbiota, including all microorganisms in a niche, through direct and indirect interactions with the host. Certain microorganisms can exist in areas conventionally considered to be sterile, such as the bone matrix. Osseous microbiota dysbiosis caused by host-microbiome perturbation or external infections may ultimately lead to osteomyelitis, a bone inflammatory disorder. Our review covers the current discoveries on the impact of host-microbiome on osteomyelitis and some common osseous diseases. Some studies suggest that the microbiotas from both osseous and non-osseous tissues (e.g., blood or gut) impact the pathogenicity of osteomyelitis and other osseous diseases (e.g., rheumatoid arthritis). We believe that this review will provide readers with a better understanding on the role of the microbiome to the host’s bone health.

Osteomyelitis: Focus on Conventional Treatments and Innovative Drug Delivery Systems

Osteomyelitis is a bone marrow infection which generally involves cortical plates and which may occur after bone trauma, orthopedic/maxillofacial surgery or after vascular insufficiency episodes. It mostly affects people from the Third World Countries, the elderly and patients affected by systemic diseases e.g. autoimmune disorders, AIDS, osteoporosis and microvascular disease. The highest percentage of osteomyelitis cases (almost 75%) is caused by Staphylococcus spp., and in particular by Staphylococcus aureus (more than 50%). The ideal classification and the diagnosis of osteomyelitis are two important tools which help the physicians to choose the best therapeutic strategies. Currently, common therapies provide an extensive debridement in association with intravenous administration of antibiotics (penicillin or clindamycin, vancomycin and fluoroquinolones among all for resistant microorganisms), to avoid the formation of sequestra. However, conventional therapeutic approach involves several drawbacks like low concentration of antibiotics in the infected site, leading to resistance and adverse effects due to the intravenous administration. For these reasons, in the last years several studies have been focused on the development of drug delivery systems such as cements, beads, scaffolds and ceramics made of hydroxyapatite (HA), calcium phosphate (CaP) and β-tricalcium phosphate (β-TCP) which demonstrated to be biocompatible, poorly toxic and capable to allow osteointegration and a prolonged drug release. The aim of this review is to provide a focus on current therapies and latest developed drug delivery systems with particular attention on those based on CaP and its derivatives, hoping that this work could allow further direction in the field of osteomyelitis.

Primary progressive multiple sclerosis in a Russian cohort: relationship with gut bacterial diversity

Background

Gut microbiota has been increasingly acknowledged to shape significantly human health, contributing to various autoimmune diseases, both intestinal and non-intestinal, including multiple sclerosis (MS). Gut microbiota studies in patients with relapsing remitting MS strongly suggested its possible role in immunoregulation; however, the profile and potential of gut microbiota involvement in patients with primary progressive MS (PPMS) patients has received much less attention due to the rarity of this disease form. We compared the composition and structure of faecal bacterial assemblage using Illumina MiSeq sequencing of V3-V4 hypervariable region of 16S rRNA genes amplicons in patients with primary progressive MS and in the healthy controls.

Results

Over all samples 12 bacterial phyla were identified, containing 21 classes, 25 orders, 54 families, 174 genera and 1256 operational taxonomic units (OTUs). The Firmicutes phylum was found to be ultimately dominating both in OTUs richness (68% of the total bacterial OTU number) and in abundance (71% of the total number of sequence reads), followed by Bacteroidetes (12 and 16%, resp.) and Actinobacteria (7 and 6%, resp.). Summarily in all samples the number of dominant OTUs, i.e. OTUs with ≥1% relative abundance, was 13, representing much less taxonomic richness (three phyla, three classes, four orders, six families and twelve genera) as compared to the total list of identified OTUs and accounting for 30% of the sequence reads number in the healthy cohort and for 23% in the PPMS cohort. Human faecal bacterial diversity profiles were found to differ between PPMS and healthy cohorts at different taxonomic levels in minor or rare taxa. Marked PPMS-associated increase was found in the relative abundance of two dominant OTUs (Gemmiger sp. and an unclassified Ruminococcaceae). The MS-related differences were also found at the level of minor and rare OTUs (101 OTUs). These changes in OTUs’ abundance translated into increased bacterial assemblage diversity in patients.

Conclusion

The findings are important for constructing a more detailed global picture of the primary progressive MS-associated gut microbiota, contributing to better understanding of the disease pathogenesis.

Staphylococcus aureus biofilm organization modulated by YycFG two-component regulatory pathway

BACKGROUND

Staphylococcus aureus (S. aureus) infection accounts for more than 50% of the osteomyelitis cases. Currently, methicillin-resistant S. aureus (MRSA) strains present an urgent medical problem. The YycFG two-component regulatory system (TCS) can allow bacteria to rapidly adapt to physical, chemical, and biological stresses. To define the role of YycFG in modulation virulence of S. aureus in osteomyelitis, we isolated clinical MRSA strains and compared these with ATCC29213 methicillin-sensitive S. aureus (MSSA).

METHODS

In the present study, 13 MRSA strains from chronic osteomyelitis tissues were isolated. The in-depth sequencing of 16S rRNA amplicons of the samples was conducted. Bacterial growth was monitored, and biofilm biomass was determined by crystal violet microtiter assay. Furthermore, quantitative RT-PCR analysis was adopted to identify the expression of yycF/G/H and icaA/D in MRSA and MSSA strains. Analysis of variance with one-way ANOVA was used for statistical analysis.

RESULTS

The in-depth sequencing of 16S rRNA amplicons of the clinical samples indicated a polymicrobial infection, with the phylum Firmicutes made up 13% of the microbial population. The MRSA strains showed an accelerated growth rate compared to the MSSA strains. Of note, MRSA biofilms showed an accumulation of an intercellular polysaccharides matrix and enhanced biomass upon microscopic examination. Furthermore, MRSA strains had a higher expression of the yycF/G/H and icaA/D genes and adhesion force.

CONCLUSIONS

These data suggested the roles of intercellular polysaccharide in S. aureus pathogenesis, indicating a possible association between YycFG pathways and MRSA strain virulence.

Microbiology of Acute and Chronic Osteomyelitis and Antibiotic Treatment

Osteomyelitis is an inflammation of bone marrow with a tendency for progression, involving the cortical plates and often periosteal tissues, with most cases occurring after trauma to bone or bone surgery or secondary to vascular insufficiency. Antimicrobial therapy and surgical débridement are the primary modalities of osteomyelitis treatment, although often it is associated with a prolonged course, requiring a large commitment between patient and clinician as well as sizable health care costs. Despite surgical and chemotherapeutic advancements, osteomyelitis remains difficult to treat, and no universally accepted protocol for treatment exists.

Rhizobacterial Community Structures Associated with Native Plants Grown in Chilean Extreme Environments

Chile is topographically and climatically diverse, with a wide array of diverse undisturbed ecosystems that include native plants that are highly adapted to local conditions. However, our understanding of the diversity, activity, and role of rhizobacteria associated with natural vegetation in undisturbed Chilean extreme ecosystems is very poor. In the present study, the combination of denaturing gradient gel electrophoresis and 454-pyrosequencing approaches was used to describe the rhizobacterial community structures of native plants grown in three representative Chilean extreme environments: Atacama Desert (ATA), Andes Mountains (AND), and Antarctic (ANT). Both molecular approaches revealed the presence of Proteobacteria, Bacteroidetes, and Actinobacteria as the dominant phyla in the rhizospheres of native plants. Lower numbers of operational taxonomic units (OTUs) were observed in rhizosphere soils from ATA compared with AND and ANT. Both approaches also showed differences in rhizobacterial community structures between extreme environments and between plant species. The differences among plant species grown in the same environment were attributed to the higher relative abundance of classes Gammaproteobacteria and Alphaproteobacteria. However, further studies are needed to determine which environmental factors regulate the structures of rhizobacterial communities, and how (or if) specific bacterial groups may contribute to the growth and survival of native plants in each Chilean extreme environments.

Distinct interacting core taxa in co-occurrence networks enable discrimination of polymicrobial oral diseases with similar symptoms

Polymicrobial diseases, which can be life threatening, are caused by the presence and interactions of multiple microbes. Peri-implantitis and periodontitis are representative polymicrobial diseases that show similar clinical symptoms. To establish a means of differentiating between them, we compared microbial species and functional genes in situ by performing metatranscriptomic analyses of peri-implantitis and periodontitis samples obtained from the same subjects (n = 12 each). Although the two diseases differed in terms of 16S rRNA-based taxonomic profiles, they showed similarities with respect to functional genes and taxonomic and virulence factor mRNA profiles. The latter—defined as microbial virulence types—differed from those of healthy periodontal sites. We also showed that networks based on co-occurrence relationships of taxonomic mRNA abundance (co-occurrence networks) were dissimilar between the two diseases. Remarkably, these networks consisted mainly of taxa with a high relative mRNA-to-rRNA ratio, with some showing significant co-occurrence defined as interacting core taxa, highlighting differences between the two groups. Thus, peri-implantitis and periodontitis have shared as well as distinct microbiological characteristics. Our findings provide insight into microbial interactions in polymicrobial diseases with unknown etiologies.

Resection and microvascular reconstruction of bisphosphonate-related osteonecrosis of the jaw: The role of microvascular reconstruction

BACKGROUND

Current treatment guidelines caution against osseous reconstruction using free flap tissue to treat bisphosphonate-related osteonecrosis of the jaw (BRONJ). The primary rationale for this stance is the theoretical risk of nonunion and recurrence of disease within the reconstruction. Emerging evidence suggests that these theoretical risks may be overestimated. We performed a literature review of this procedure for the treatment of advanced BRONJ. We also present a new case report of resection and microvascular reconstruction in a 58-year-old man with stage III BRONJ.

METHODS

A MEDLINE search was performed to gather all reports of maxillary and mandibular reconstruction using free tissue flap transfer for BRONJ. Inclusion criteria were confirmed stage II or III BRONJ, free tissue transfer and reconstruction, and reported complications. Articles were excluded if they contained only local flap reconstruction, wound closure without reconstruction, or osteoradionecrosis. Outcomes from our case report were added to the analysis.

RESULTS

We identified 10 articles that met criteria. Adding our case, we identified 40 cases of free flap reconstruction. The rate of nonunion was 5% (2 of 40). Fistulas formed in 4 cases (10%). BRONJ recurred in 2 cases (5%).

CONCLUSION

Complication rates after free flap microvascular reconstruction in BRONJ seem acceptable. Nonunion is relatively rare and should not be the sole reason to recommend against free flap reconstruction. A randomized clinical trial would help clarify the role of this procedure in refractory BRONJ; however, we believe that segmental resection and microvascular reconstruction is a viable option in select cases of BRONJ. © 2016 Wiley Periodicals, Inc. Head Neck 38:1278-1285, 2016.

The microbiome of diabetic foot osteomyelitis

The purpose of this investigation was to evaluate the diversity of bacteria in diabetic foot osteomyelitis using a 16S rRNA sequencing approach and to compare the results with conventional culture techniques. In this prospective observational study, we obtained 34 bone samples from patients admitted to our hospital with a moderate–severe diabetic foot infection. We analysed the distribution of the 16S rRNA gene sequences in the bone samples, using an Illumina MiSeq Personal Sequencer. We compared the genera that were detected with the cultured pathogens in the bone samples with conventional techniques. In the 23 samples that had positive results with both techniques, Staphylococcus, Corynebacterium, Streptococcus and Propionibacterium spp. were detected in 20, 18, 13 and 11 samples, respectively. Significantly more anaerobes were detected with 16S rRNA sequencing compared to conventional techniques (86.9 % vs. 23.1 %, p = 0.001) and more Gram-positive bacilli were present (78.3 % vs. 3.8 %, p < 0.001). Staphylococcus spp. were identified in all of the sequenced bone samples that were negative with conventional techniques. Mixed genera were present in 83.3 % (5 of 6) of the negative samples. Anaerobic and fastidious organisms may play a more significant role in osteomyelitis than previously reported. Further studies with larger populations are needed in order to fully understand the clinical importance of the microbial diversity of diabetic foot osteomyelitis.

Histologic, Clinical, and Radiologic Findings of Alveolar Bone Expansion and Osteomyelitis of the Jaws in Cats

The objective of this study was to characterize clinical, radiologic, and histologic patterns of alveolar bone expansion and osteomyelitis in cats. Based on case materials submitted as surgical biopsy specimens, alveolar bone pathology was diagnosed in 28 cats. These cats had a total of 37 oral lesions with clinical and radiologic changes that involved bone and/or teeth, including periodontitis, bone expansion, tooth resorption, and/or chronic osteomyelitis; 32 lesions were evaluated by histopathology. Canine teeth were affected in 19 cats (27 affected teeth), with bilateral lesions in 5 (26.3%) cats. The caudal premolar and/or molar regions were affected in 10 cats (10 affected sites). All biopsy sites evaluated by a review of clinical images and/or radiographs had evidence of periodontitis. Clinical photographs showed expansion of alveolar bone in 13 of 16 (81%) biopsy sites evaluated. Radiologically, rarifying osseous proliferation of alveolar bone was seen at 26 of 27 (96%) biopsy sites, and tooth resorption occurred at 15 of 18 (83%) sites. Histologically, the tissue samples from canine sites had compressed trabeculae of mature remodeled bone, loose fibrous stroma with paucicellular inflammation, and mild proliferation of woven bone. Tissue samples from the premolar/molar biopsy sites were often highly cellular with mixed lymphoplasmacytic and chronic suppurative inflammation, ulceration with granulation tissue, and robust proliferation of woven bone. Alveolar bone expansion and osteomyelitis in cats occurs in conjunction with periodontal inflammation and frequently with tooth resorption.

Oral microbiota and host innate immune response in bisphosphonate-related osteonecrosis of the jaw

Bacterial biofilms have emerged as potential critical triggers in the pathogenesis of bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) or BRONJ. BRONJ lesions have shown to be heavily colonized by oral bacteria, most of these difficult to cultivate and presents many clinical challenges. The purpose of this study was to characterize the bacterial diversity in BRONJ lesions and to determine host immune response. We examined tissue specimens from three cohorts (n=30); patients with periodontal disease without a history of BP therapy (Control, n=10), patients with periodontal disease having history of BP therapy but without ONJ (BP, n=5) and patients with BRONJ (BRONJ, n=15). Denaturing gradient gel electrophoresis of polymerase chain reaction (PCR)-amplified 16S rRNA gene fragments revealed less bacterial diversity in BRONJ than BP and Control cohorts. Sequence analysis detected six phyla with predominant affiliation to Firmicutes in BRONJ (71.6%), BP (70.3%) and Control (59.1%). Significant differences (P<0.05) in genera were observed, between Control/BP, Control/BRONJ and BP/BRONJ cohorts. Enzyme-linked immunosorbent assay (ELISA) results indicated that the levels of myeloperoxidase were significantly lower, whereas interleukin-6 and tumor necrosis factor-alpha levels were moderately elevated in BRONJ patients as compared to Controls. PCR array showed significant changes in BRONJ patients with downregulation of host genes, such as nucleotide-binding oligomerization domain containing protein 2, and cathepsin G, the key modulators for antibacterial response and upregulation of secretory leukocyte protease inhibitor, proteinase 3 and conserved helix-loop-helix ubiquitous kinase. The results suggest that colonization of unique bacterial communities coupled with deficient innate immune response is likely to impact the pathogenesis of ONJ.