Development and biological evaluation of Ti6Al7Nb scaffold implants coated with gentamycin-saturated bacterial cellulose biomaterial

Herein we present an innovative method of coating the surface of Titanium-Aluminium-Niobium bone scaffold implants with bacterial cellulose (BC) polymer saturated with antibiotic. Customized Ti6Al7Nb scaffolds manufactured using Selective Laser Melting were immersed in a suspension of Komagataeibacter xylinus bacteria which displays an ability to produce a 3-dimensional structure of bio-cellulose polymer. The process of complete implant coating with BC took on average 7 days. Subsequently, the BC matrix was cleansed by means of alkaline lysis and saturated with gentamycin. Scanning electron microscopy revealed that BC adheres and penetrates into the implant scaffold structure. The viability and development of the cellular layer on BC micro-structure were visualized by means of confocal microscopy. The BC-coated implants displayed a significantly lower cytotoxicity against osteoblast and fibroblast cell cultures in vitro in comparison to non-coated implants. It was also noted that gentamycin released from BC-coated implants inhibited the growth of Staphylococcus aureus cultures in vitro, confirming the suitability of such implant modification for preventing hostile microbial colonization. As demonstrated using digital microscopy, the procedure used for implant coating and BC chemical cleansing did not flaw the biomaterial structure. The results presented herein are of high translational value with regard to future use of customized, BC-coated and antibiotic-saturated implants designed for use in orthopedic applications to speed up recovery and to reduce the risk of musculoskeletal infections.

Innate Immunity to Staphylococcus aureus: Evolving Paradigms in Soft Tissue and Invasive Infections

Staphylococcus aureus causes a wide range of diseases that together embody a significant public health burden. Aided by metabolic flexibility and a large virulence repertoire, S. aureus has the remarkable ability to hematogenously disseminate and infect various tissues, including skin, lung, heart, and bone, among others. The hallmark lesions of invasive staphylococcal infections, abscesses, simultaneously denote the powerful innate immune responses to tissue invasion as well as the ability of staphylococci to persist within these lesions. In this article, we review the innate immune responses to S. aureus during infection of skin and bone, which serve as paradigms for soft tissue and bone disease, respectively.

Historic Treponema pallidum genomes from Colonial Mexico retrieved from archaeological remains

Treponema pallidum infections occur worldwide causing, among other diseases, syphilis and yaws. In particular sexually transmitted syphilis is regarded as a re-emerging infectious disease with millions of new infections annually. Here we present three historic T. pallidum genomes (two from T. pallidum ssp. pallidum and one from T. pallidum ssp. pertenue) that have been reconstructed from skeletons recovered from the Convent of Santa Isabel in Mexico City, operational between the 17th and 19th century. Our analyses indicate that different T. pallidum subspecies caused similar diagnostic presentations that are normally associated with syphilis in infants, and potential evidence of a congenital infection of T. pallidum ssp. pertenue, the causative agent of yaws. This first reconstruction of T. pallidum genomes from archaeological material opens the possibility of studying its evolutionary history at a resolution previously assumed to be out of reach.

Gut Microbiota, Immune System, and Bone

The gut microbiota (GM) is the whole of commensal, symbiotic, and pathogenic microorganisms living in our intestine. The GM-host interactions contribute to the maturation of the host immune system, modulating its systemic response. It is well documented that GM can interact with non-enteral cells such as immune cells, dendritic cells, and hepatocytes, producing molecules such as short-chain fatty acids, indole derivatives, polyamines, and secondary bile acid. The receptors for some of these molecules are expressed on immune cells, and modulate the differentiation of T effector and regulatory cells: this is the reason why dysbiosis is correlated with several autoimmune, metabolic, and neurodegenerative diseases. Due to the close interplay between immune and bone cells, GM has a central role in maintaining bone health and influences bone turnover and density. GM can improve bone health also increasing calcium absorption and modulating the production of gut serotonin, a molecule that interacts with bone cells and has been suggested to act as a bone mass regulator. Thus, GM manipulation by consumption of antibiotics, changes in dietary habits, and the use of pre- and probiotics may affect bone health. This review summarizes evidences on the influence of GM on immune system and on bone turnover and density and how GM manipulation may influence bone health.

Osteomicrobiology: A New Cross-Disciplinary Research Field

The mutualistic interaction between the gut microbiota (GM) and its host profoundly shapes many aspects of our physiology. The composition and activity of the gut microbiota is modulated by environmental factors such as dietary habits and antibiotic treatments. In rodents, studies demonstrate that the GM is a crucial regulator of bone metabolism and that modulation of the GM composition by probiotic interventions can prevent castration-induced bone loss. Short-term colonization of germ-free mice with GM results in an activation of CD4+T cells, resulting in increased levels of pro-inflammatory cytokines in bone and thereby activation of osteoclastic bone resorption. Besides these immune-mediated effects on bone mass, the GM is involved in nutritional uptake and may, thereby, regulate overall body growth and bone sizes possibly mediated via altered IGF-I levels. We recently introduced a new term "osteomicrobiology" for the rapidly emerging research field of the role of the microbiota in bone health. This research field is aimed to bridge the gaps between bone physiology, gastroenterology, immunology, and microbiology. Future studies will determine if the GM is a novel therapeutic target for osteoporosis and if the GM composition might be used as a biomarker for fracture prediction.

Prebiotics, Bone and Mineral Metabolism

Increasing interest in functional foods has driven discovery in the area of bioactive compounds. Prebiotics are non-digestible carbohydrate compounds that, when consumed, elicit health benefits and aid in the prevention and treatment of chronic diseases. While prebiotics have been shown to improve a number of chronic, inflammatory conditions, growing evidence exists for prebiotic effects on calcium metabolism and bone health. These novel dietary fibers have been shown to increase calcium absorption in the lower intestines of both preclinical and human models. Rodent models have also been imperative for understanding prebiotic effects on bone mineral density and measures of skeletal strength. Although fewer data are available for humans, bone-related prebiotic effects exist across the lifecycle, suggesting benefits for attainment of peak bone mass during adolescence and minimized bone resorption among postmenopausal women. These effects are thought to occur through prebiotic-microbe interactions in the large intestine. Current prebiotic mechanisms for improved mineral absorption and skeletal health include alterations in gut microbiota composition, production of short-chain fatty acids, altered intestinal pH, biomarker modification, and immune system regulation. While the majority of available data support improved mineral bioavailability, emerging evidence suggests alternate microbial roles and the presence of an intricate gut-bone signaling axis. Overall, the current scientific literature supports prebiotic consumption as a cost-effective and sustainable approach for improved skeletal health and/or fracture prevention. The goal of this review is to discuss both foundational and recent research in the area of prebiotics, mineral metabolism, and bone health.

Effects of Fermented Milk Products on Bone

Fermented milk products like yogurt or soft cheese provide calcium, phosphorus, and protein. All these nutrients influence bone growth and bone loss. In addition, fermented milk products may contain prebiotics like inulin which may be added to yogurt, and provide probiotics which are capable of modifying intestinal calcium absorption and/or bone metabolism. On the other hand, yogurt consumption may ensure a more regular ingestion of milk products and higher compliance, because of various flavors and sweetness. Bone mass accrual, bone homeostasis, and attenuation of sex hormone deficiency-induced bone loss seem to benefit from calcium, protein, pre-, or probiotics ingestion, which may modify gut microbiota composition and metabolism. Fermented milk products might also represent a marker of lifestyle promoting healthy bone health.

Impact of Fluoroscopically Guided Bone Biopsy on Antibiotic Management of Osteomyelitis in the Lower Extremity

This study evaluated the impact of fluoroscopically guided percutaneous bone biopsy on altering antibiotic regimens in lower extremity osteomyelitis. Eighty-eight patients who received fluoroscopically guided bone biopsies were identified. There was bacterial growth in 28% of bone biopsies overall. The rate of positive culture was decreased in patients started on empiric antibiotics before biopsy (23%) compare with patients without empiric antibiotics (44%). Antibiotic regimens were changed in 24% of patients overall in response to culture data. The majority of positive biopsy cultures (76%) but minority of negative biopsy cultures (3%) resulted in a change to antibiotic regimens. The impact of percutaneous bone biopsy on antibiotic management of adult patients with osteomyelitis diagnosed by magnetic resonance imaging is modest and is decreased in patients previously started on antibiotics. Despite its modest impact, bone biopsy results can provide useful information in antibiotic management, especially when positive (Journal of Surgical Orthopaedic Advances 27(4):277-280, 2018).

Bone responses in health and infectious diseases: A focus on osteoblasts

Historically, bone was thought to be immunologically inactive with the sole function of supporting locomotion and ensuring stromaness functions as a major lymphoid organ. However, a myriad of pathogens (bacteria such as staphylococcus as well as viruses including alphaviruses, HIV or HCV) can invade the bone. These pathogens can cause apoptosis, autophagy and necrosis of osteoblasts and lead to lymphopenia and immune paralysis. There are now several detailed studies on how osteoblasts contribute to innate immune and inflammatory responses; indeed, osteoblasts in concert with resident macrophages can engage an armory of defense mechanisms capable of detecting and controlling pathogen evasion mechanisms. Osteoblasts can express the so-called pattern recognition receptors such as TOLL-like receptors involved in the detection for example of lipids and unique sugars (polysaccharides and polyriboses) expressed by bacteria or viruses (e.g. LPS and RNA respectively). Activated osteoblasts can produce interferon type I, cytokines, chemokines and interferon-stimulated proteins through autocrine and paracrine mechanisms to control for viral replication and to promote phagocytosis or lysis of bacteria for example by defensins. Uncontrolled and sustained innate immune activation of infected osteoblasts will also lead to an imbalance in the production of osteoclastogenic factors such as RANKL and osteoprotegerin involved in bone repair.

Comprehensive analysis of microorganisms accompanying human archaeological remains

Metagenome analysis has become a common source of information about microbial communities that occupy a wide range of niches, including archaeological specimens. It has been shown that the vast majority of DNA extracted from ancient samples come from bacteria (presumably modern contaminants). However, characterization of microbial DNA accompanying human remains has never been done systematically for a wide range of different samples. We used metagenomic approaches to perform comparative analyses of microorganism communities present in 161 archaeological human remains. DNA samples were isolated from the teeth of human skeletons dated from 100 AD to 1200 AD. The skeletons were collected from 7 archaeological sites in Central Europe and stored under different conditions. The majority of identified microbes were ubiquitous environmental bacteria that most likely contaminated the host remains not long ago. We observed that the composition of microbial communities was sample-specific and not correlated with its temporal or geographical origin. Additionally, traces of bacteria and archaea typical for human oral/gut flora, as well as potential pathogens, were identified in two-thirds of the samples. The genetic material of human-related species, in contrast to the environmental species that accounted for the majority of identified bacteria, displayed DNA damage patterns comparable with endogenous human ancient DNA, which suggested that these microbes might have accompanied the individual before death. Our study showed that the microbiome observed in an individual sample is not reliant on the method or duration of sample storage. Moreover, shallow sequencing of DNA extracted from ancient specimens and subsequent bioinformatics analysis allowed both the identification of ancient microbial species, including potential pathogens, and their differentiation from contemporary species that colonized human remains more recently.

The Cause of Death of a Child in the 18th Century Solved by Bone Microbiome Typing Using Laser Microdissection and Next Generation Sequencing

The history of medicine abounds in cases of mysterious deaths, especially by infectious diseases, which were probably unresolved because of the lack of knowledge and of appropriate technology. The aim of this study was to exploit contemporary technologies to try to identify the cause of death of a young boy who died from a putative “infection” at the end of the 18th century, and for whom an extraordinarily well-preserved minute bone fragment was available. After confirming the nature of the sample, we used laser microdissection to select the most “informative” area to be examined. Tissue genotyping indicated male gender, thereby confirming the notary’s report. 16S ribosomal RNA sequencing showed that Proteobacteria and Actinobacteria were more abundant than Firmicutes and Bacteroidetes, and that Pseudomonas was the most abundant bacterial genus in the Pseudomonadaceae family. These data suggest that the patient most likely died from Pseudomonas osteomyelitis. This case is an example of how new technological approaches, like laser microdissection and next-generation sequencing, can resolve ancient cases of uncertain etiopathology. Lastly, medical samples may contain a wealth of information that may not be accessible until more sophisticated technology becomes available. Therefore, one may envisage the possibility of systematically storing medical samples for evaluation by future generations.

Diagnostic value of sinus tract culture versus intraoperative bone culture in patients with chronic osteomyelitis

To compare the organisms isolated from the sinus tract culture and intraoperative bone culture in patients with chronic osteomyelitis. This cross sectional prospective study was conducted from February 2015 to March 2016. Ninety consecutive patients were enrolled in study (n=90). Inclusion criteria were patients with either sex, any age, chronic osteomyelitis having discharging sinus. Sample from sinus tracts and bone were taken through standardized aseptic technique and organism were cultured. There were 62 males and 28 females, male to female ratio 3:1, mean age was 40 years. 23 patients had primary osteomyelitis and 67 had secondary osteomyelitis. 68 patients had orthopaedic implant infections. In 61/90 (67%) patients the same organism was isolated on both sinus tract and intraoperative cultures.In our scenario we found that within the limitations of this study, there was a high ratio of agreement between the sinus tract and intraoperative cultures. We conclude that if used judiciously, sinus tract cultures can yield accurate results in the majority of cases.

[The microbiological study of purulent focus of inflammation in patients with chronic osteomyelitis of long bones]

The article presents analysis of results of microbiological study of pathologic samples from fistula and surgical wounds of 155 patients with chronic osteomyelitis of long bones in the period of exacerbation of disease during 2014-2015. In totality, 126 samples from fistula and 95 samples from wounds were analyzed. Correspondingly, 164 and 102 strains of bacteria were separated. The microbial contamination of fistula and wounds was established. The species composition of microflora was analyzed. It is established that in the analyzed groups the main agent still continues to be staphylococcus and priority pathogen Staphylococcus aureus differing slightly in rate of occurrence and coefficient of resistance. MRSA was separated up to 5.6% more often from surgical wounds than from fistula. The highest detection rate of strains S. aureus and MRSA falls on 2009-2010. In 2015, the lowest detection rate of S. aureus was marked with relatively high rate of detection of MRSA. The disk diffusion D-test was applied to determine resistance of inducible type to Clindamycin of 17 strains of S. aureus resistant to Erythromycin and sensitive to Clindamycin. The inducible resistance to Clindamycin for strains from surgery pounds made up to 62.5% that is three times higher than in case of strains separated from fistula. The important role in development of chronic of osteomyelitis of long bones is played by Gram-negative microorganisms (E. coli, Enterobacter, P. aeruginosa, etc.). The rate of detection of these microorganisms in surgery wounds makes up to 22.5% and 17.1% in fistula.

Use of MALDI-TOF mass spectrometry after liquid enrichment (BD Bactec™) for rapid diagnosis of bone and joint infections

Advantages of MALDI-TOF MS (MS) were evaluated for diagnosis of bone and joint infections after enrichment of synovial fluid (SF) or crushed osteoarticular samples (CSs). MS was performed after enrichment of SF or crushed osteoarticular samples CS (n = 108) in both aerobic and anaerobic vials. Extraction was performed on 113 vials (SF: n = 47; CS: n = 66), using the Sepsityper^® kit prior identification by MS. The performances of MS, score and reproducibility results on bacterial colonies from blood agar and on pellets after enrichment in vials, were compared. MS analysis of the vial resulted in correct identification of bacteria at a species and genus level (80.5% and 92% of cases, respectively). The reproducibility was superior for aerobic Gram-positive bacteria (Staphylococci and Gram-positive bacilli: 100% colonies), as compared to aerobic Gram-negative bacilli (89.7%), anaerobes (83.3%) and Streptococcus/Enterococcus (58.8%). MS performance was significantly better for staphylococci than for streptococci on all identification parameters. For polymicrobial cultures, identification (score>1.5) of two species by MS was acceptable in 92.8% of cases. Use of MS on enrichment pellets of bone samples is an accurate, rapid and robust method for bacterial identification of clinical isolates from osteoarticular infections, except for streptococci, whose identification to species level remains difficult.

Incidence of Propionibacterium acnes in initially culture-negative thioglycollate broths-a prospective cohort study at a Danish University Hospital

The aim of this study was to prospectively investigate the incidence of Propionibacterium acnes in thioglycollate broths reported as culture-negative at the Department of Clinical Microbiology, Rigshospitalet, to evaluate whether 5 days of incubation was enough to find all relevant cases. Five hundred thioglycollate broths reported as culture-negative after 5 days were consecutively collected and incubated for at least a further 9 days (at least 14 days of incubation in total). Only tissue samples from sterile sites of the body (n = 298), bone tissue (n = 197) and foreign material (n = 5) were included in this study. Samples were divided into two groups: infected group and control group. This made it possible to compare findings between groups, thereby making it possible to estimate the level of true-positive findings and contamination. Samples from 296 participants were included in this study. After exclusion criteria were met, P. acnes was cultured from ten out of 151 patients (6.6%) in the infected group and from one out of 138 participants (0.7%) in the control group. This resulted in more findings of P. acnes in the infected group on day 14 than on day 5 (p 0.002). Furthermore, P. acnes was cultured more often from bone tissue and tissue surrounding foreign materials on day 14 than on day 5 (p 0.04). Clinical microbiology laboratories should consider incubating thioglycollate broths for at least 14 days to find all relevant cases of P. acnes, especially when it comes to bone tissue and tissue surrounding foreign materials.

Disseminated mucormycosis (DM) after pneumonectomy: a case report

BACKGROUND

Mucormycosis is a kind of rare opportunistic fungal disease and the incidence of which has gradually increased. Disseminated mucormycosis (DM) is a life-threatening infection that mostly occurs in immunocompromised patients. The lung and brain are usually involved in disseminated mucormycosis, and other sites are scare. We report the first case of disseminated mucormycosis whose infection sites included lung, skin, liver, vertebra, and spinal cord that ensued after a right lung pneumonectomy in an immunocompetent patient.

CASE PRESENTATION

A 20-year-old female underwent a right lung pneumonectomy for "lung cancer" presented with an intermittent fever for two years. A computed tomography (CT) scan showed an enclosed outstanding mass in the right chest wall. The patient also suffered from lower limb numbness and weakness, difficulty walking, and dysuria. Medical examination showed superficial feeling of the abdominal wall was decreased from the T7 and T8 level; muscle strength for both lower limbs was decreased; muscle tension of both lower limbs was also diminished. A biopsy through the right chest wall mass and thoracic mass by fistula of chest wall showed broad nonseptate hyphae with right-angle branching, consistent with mucormycosis. With titration of amphotericin B and its lipid complex, the patient recovered.

CONCLUSIONS

Our case showed an unusual clinical presentation of disseminated mucormycosisin an immunocompetent patient.

Outbreaks of Pythiosis in Two Flocks of Sheep in Northeastern Brazil

Two outbreaks of cutaneous pythiosis caused by Pythium insidiosum were diagnosed in two herds of crossbred hair wool sheep of different ages in the semiarid region of Northeastern Brazil. In one herd of 120 sheep, 40 were affected. The other outbreak affected six sheep out of 80. Local swellings with ulcerative lesions were observed in the limbs and abdominal and prescapular regions. Three sheep were necropsied. Two of them had lung metastasis characterized by multifocal nodules measuring 0.5–2 cm. In one animal, the prescapular lymph node was also affected. In another, the cutaneous lesion extended to the sesamoid bone. Microscopically, there were multifocal granulomas with intralesional P. insidiosum hyphae and Splendore-Hoeppli material surrounding the hyphae. The diagnosis was based on the histologic lesions, immunohisto-chemical identification, and culture of the etiologic agent. One sheep treated with potassium iodide recovered. Standing in swampy water for long periods in a warm aquatic environment seems to be the reason for the high prevalence of the disease.

Genotype Analysis of Bacillus anthracis Strains Circulating in Bangladesh

In Bangladesh, anthrax, caused by the bacterium Bacillus anthracis, is considered an endemic disease affecting ruminants with sporadic zoonotic occurrences in humans. Due to the lack of knowledge about risks from an incorrect removal of infected carcasses, the disease is not properly monitored, and because of the socio-economic conditions, the situation is under-reported and under-diagnosed. For sensitive species, anthrax represents a fatal outcome with sudden death and sometimes bleeding from natural orifices. The most common source of infection for ruminants is ingestion of spores during grazing in contaminated pastures or through grass and water contaminated with anthrax spores. Domestic cattle, sheep and goats can also become infected through contaminated bone meal (used as feed) originating from anthrax-infected carcasses. The present investigation was conducted to isolate B. anthracis organisms from 169 samples (73 soil, 1 tissue, 4 bone and 91 bone meal samples) collected from 12 different districts of Bangladesh. The sampling was carried out from 2012 to 2015. Twelve samples resulted positive for B. anthracis. Biomolecular analyses were conducted starting from the Canonical Single Nucleotide Polymorphism (CanSNP) to analyze the phylogenetic origin of strains. The analysis of genotype, obtained through the Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) with the analysis of 15 Variable Number Tandem Repeats (VNTR), demonstrated four different genotypes: two of them were previously identified in the district of Sirajganj. The sub-genotyping, conducted with Single Nucleotide Repeats analysis, revealed the presence of eight subgenotypes. The data of the present study concluded that there was no observed correlation between imported cattle feed and anthrax occurrence in Bangladesh and that the remarkable genetic variations of B. anthracis were found in the soil of numerous outbreaks in this country.

Biomaterials with Antibacterial and Osteoinductive Properties to Repair Infected Bone Defects

The repair of infected bone defects is still challenging in the fields of orthopedics, oral implantology and maxillofacial surgery. In these cases, the self-healing capacity of bone tissue can be significantly compromised by the large size of bone defects and the potential/active bacterial activity. Infected bone defects are conventionally treated by a systemic/local administration of antibiotics to control infection and a subsequent implantation of bone grafts, such as autografts and allografts. However, these treatment options are time-consuming and usually yield less optimal efficacy. To approach these problems, novel biomaterials with both antibacterial and osteoinductive properties have been developed. The antibacterial property can be conferred by antibiotics and other novel antibacterial biomaterials, such as silver nanoparticles. Bone morphogenetic proteins are used to functionalize the biomaterials with a potent osteoinductive property. By manipulating the carrying modes and release kinetics, these biomaterials are optimized to maximize their antibacterial and osteoinductive functions with minimized cytotoxicity. The findings, in the past decade, have shown a very promising application potential of the novel biomaterials with the dual functions in treating infected bone defects. In this review, we will summarize the current knowledge of novel biomaterials with both antibacterial and osteoinductive properties.

Testing the Hypothesis of Biofilm as a Source for Soft Tissue and Cell-Like Structures Preserved in Dinosaur Bone

Recovery of still-soft tissue structures, including blood vessels and osteocytes, from dinosaur bone after demineralization was reported in 2005 and in subsequent publications. Despite multiple lines of evidence supporting an endogenous source, it was proposed that these structures arose from contamination from biofilm-forming organisms. To test the hypothesis that soft tissue structures result from microbial invasion of the fossil bone, we used two different biofilm-forming microorganisms to inoculate modern bone fragments from which organic components had been removed. We show fundamental morphological, chemical and textural differences between the resultant biofilm structures and those derived from dinosaur bone. The data do not support the hypothesis that biofilm-forming microorganisms are the source of these structures.

Fungal Ferromanganese Mineralisation in Cretaceous Dinosaur Bones from the Gobi Desert, Mongolia

Well-preserved mycelia of fungal- or saprolegnia-like biota mineralised by ferromanganese oxides were found for the first time in long bones of Late Cretaceous dinosaurs from the Gobi Desert (Nemegt Valley, Mongolia). The mycelia formed a biofilm on the wall of the bone marrow cavity and penetrated the osteon channels of the nearby bone tissue. Optical microscopy, Raman, SEM/EDS, SEM/BSE, electron microprobe and cathodoluminescence analyses revealed that the mineralisation of the mycelia proceeded in two stages. The first stage was early post-mortem mineralisation of the hyphae by Fe/Mn-oxide coatings and microconcretions. Probably this proceeded in a mildly acidic to circumneutral environment, predominantly due to heterotrophic bacteria degrading the mycelial necromass and liberating Fe and Mn sorbed by the mycelia during its lifetime. The second stage of mineralisation, which proceeded much later following the final burial of the bones in an alkaline environment, resulted from the massive precipitation of calcite and occasionally barite on the iron/manganese-oxide-coated mycelia. The mineral phases produced by fungal biofilms colonising the interiors of decaying dinosaur bones not only enhance the preservation (fossilisation) of fungal remains but can also be used as indicators of the geochemistry of the dinosaur burial sites.

Challenges in diagnosing infection in the diabetic foot

Diagnosing the presence of infection in the foot of a patient with diabetes can sometimes be a difficult task. Because open wounds are always colonized with microorganisms, most agree that infection should be diagnosed by the presence of systemic or local signs of inflammation. Determining whether or not infection is present in bone can be especially difficult. Diagnosis begins with a history and physical examination in which both classic and 'secondary' findings suggesting invasion of microorganisms or a host response are sought. Serological tests may be helpful, especially measurement of the erythrocyte sedimentation rate in osteomyelitis, but all (including bone biomarkers and procalcitonin) are relatively non-specific. Cultures of properly obtained soft tissue and bone specimens can diagnose and define the causative pathogens in diabetic foot infections. Newer molecular microbial techniques, which may not only identify more organisms but also virulence factors and antibiotic resistance, look very promising. Imaging tests generally begin with plain X-rays; when these are inconclusive or when more detail of bone or soft tissue abnormalities is required, more advanced studies are needed. Among these, magnetic resonance imaging is generally superior to standard radionuclide studies, but newer hybrid imaging techniques (single-photon emission computed tomography/computed tomography, positron emission tomography/computed tomography and positron emission tomography/magnetic resonance imaging) look to be useful techniques, and new radiopharmaceuticals are on the horizon. In some cases, ultrasonography, photographic and thermographic methods may also be diagnostically useful. Improved methods developed and tested over the past decade have clearly increased our accuracy in diagnosing diabetic foot infections.

Ancient pathogens in museal dry bone specimens: analysis of paleocytology and aDNA

Bone samples investigated in this study derive from the pathologic-anatomical collection of the Natural History Museum of Vienna. In order to explore the survival of treponemes and treponemal ancient DNA in museal dry bone specimens, we analyzed three individuals known to have been infected with Treponema pallidum pallidum. No reproducible evidence of surviving pathogen's ancient DNA (aDNA) was obtained, despite the highly sensitive extraction and amplification techniques (TPP15 and arp). Additionally, decalcification fluid of bone sections was smear stained with May-Gruenwald-Giemsa. The slides were examined using direct light microscope and dark field illumination. Remnants of spirochetal structures were detectable in every smear. Our results demonstrate that aDNA is unlikely to survive, but spirochetal remains are stainable and thus detectable.