Invasion of bone cells by Staphylococcus epidermidis

Bone implants infected with Staphylococcus epidermidis often require surgical intervention because of the failure of antibiotic treatment. The reasons why such infections are resistant to therapy are poorly understood. We have previously reported that another bacterium, Staphylococcus aureus, can invade bone cells and thereby evade antimicrobial therapy. In this study we have investigated the hypothesis that S. epidermidis can also invade bone cells and may therefore explain the difficulties of treating infections with this organism. We found that S. epidermidis was capable of invading bone cells but that there were significant strain dependent differences in this capacity. A recombinant protein encompassing the D1-D4 repeat region of S. aureus fibronectin-binding protein B completely inhibited internalization of S. aureus but failed to block internalization of S. epidermidis. Similarly a blocking antibody to alpha5beta1 integrin inhibited internalization of S. aureus by bone cells but had no effect on the uptake of S. epidermidis. Therefore unlike S. aureus, S. epidermidis does not gain entrance into bone cells through a fibronectin bridge between the alpha5beta1 integrin and a bacterial adhesin.

Comparative study of cryopreserved bone tissue and tissue preserved in a 98% glycerol solution

OBJECTIVE

To compare the bone graft cryopreservation method (at -80 degrees C) with a preservation method using a 98% glycerol solution at room temperature (10 degrees C-35 degrees C), by testing the antibacterial and fungal effects of 98% glycerol and comparatively analyzing the observed histological changes resulting from the use of both methods.

METHOD

This study was of 30 samples of trabecular bone tissue from 10 patients undergoing total hip arthroplasty. Each femoral head provided 3 samples that were randomized into 3 groups, namely, the control group, the cryopreserved group, and the group preserved in a 98% glycerol at room temperature for 1 year. The samples were submitted to histomorphologic, cell feasibility, and microbiologic analyses. The results were statistically analyzed using the McNemar test, with a statistical significance index of 0.05.

RESULTS

Values obtained using the McNemar test to compare probability distributions of histomorphologic variables (mature or lamellar bone, immature bone, and necrosis) and cell feasibility (osteoblasts and osteoclasts) indicated that there is no difference between the distributions of variables under the 3 experimental conditions. Microbiological analysis of the 98% glycerol solution and bone fragments from samples stored for 1 year at room temperature did not show bacterial or fungal growth. The histological and microbiological investigation were performed at 2 different time points: immediately after the sample processing and after 1 year.

CONCLUSION

The method used to preserve bone grafts kept in 98% glycerol at room temperature (10 degrees C-35 degrees C) was similar to cryopreservation in terms of bone matrix preservation; no bacteria or fungi were found in the samples.

A Rhizopus oryzae strain isolated from resected bone and soft tissue specimens from a sinonasal and palatal mucormycosis case. Report of a case and in vitro experiments of yeastlike cell development

We report a histologically and mycologically proven sinonasal mucormycosis case causing palatal necrosis in a nondiabetic patient with renal failure. Mycological examination of Giemsa stained imprinted tissue preparations revealed abundant yeast-like cells besides the typical mucoraceous hyphae. The fungus was isolated from surgical specimens and identified as Rhizopus oryzae by phenotypic and genotypic tests. Laboratory studies were performed to investigate the association of the yeast-like cells observed in tissue specimens and the fungus recovered in culture. In vitro induced yeast-like cell development of the case isolate was found under certain growth conditions and documented by photomicrographs.

Tuberculosis in adolescents: A French retrospective study of 52 cases

BACKGROUND

The only available data about tuberculosis (TB) among adolescents date back to the 1980s, although the incidence of tuberculosis has been increasing in this age group.

METHODS

Medical records were reviewed for all adolescents aged 12 to 18 years hospitalized with the diagnosis of TB in Avicenne/Jean Verdier Teaching hospital (Seine-Saint-Denis, suburb of Paris) between September 2000 and December 2004.

RESULTS

Of the 52 patients identified, 52% were female. Median age at diagnosis was 15 years (range, 12-18 years). The proportion of adolescents known to be born abroad was 90%. Diagnoses resulted from the examination of a sick child in 79% of cases, a case contact investigation of an adult suspected of having TB in 19% and routine tuberculin skin test in 2%. Twenty-seven of 52 patients (52%) had isolated pulmonary disease. Sixteen patients (31%) had pulmonary and extrapulmonary TB and 8 cases (17%) had exclusively extrapulmonary disease. The site of extrapulmonary TB included pleural (n = 8), meningitis (n = 4), lymph node (n = 4), peritoneal (n = 5), osteoarticular (n = 3) and genitourinary (n = 1). TB was confirmed by the isolation of Mycobacterium tuberculosis from sputum (n = 21), gastric aspirate (n = 8), bone (n = 1) or cerebrospinal fluid (n = 2). No case had a relapse or recurrence of disease in median 3.2 years of follow up.

CONCLUSIONS

Our results indicate that demographic and clinical characteristics of adolescents with TB differed from adults and children. A specific approach to the prevention and treatment of TB in adolescents is absolutely necessary.

Autogenous particulate bone collected with a piezo-electric surgical device and bone trap: a microbiological and histomorphometric study

The aims of this study were to determine the microbiological and particle size characteristics of particulate bone collected with a piezosurgery device and bone trap, and to reduce bacterial contamination after treatment of debris with rifamycin SV. Samples were taken from 10 patients who underwent surgical extraction of their third lower molars. The ostectomy was performed with a piezosurgery device, and the debris was collected with a surgical aspiration set equipped with a bone trap. Two aliquots were taken from each sample, one of which was treated with rifamycin SV. The second aliquot, used as a control, was treated with a physiological solution. In the samples immersed in antibiotic solution, there was a statistically significant (P<0.005) reduction in bacterial contamination. The stringent protocol followed in this study has proved valid for collection of material, and treatment with rifamycin SV was found to reduce bacterial contamination in collected material.

Infection of the appendicular skeleton

In relation to the clinical course, infection in bone can be divided into acute, subacute and chronic osteomyelitis. The diagnosis of acute osteomyelitis is often challenging but can best be made by correlating radiography, bone scintigraphy and MRI with clinical information. Radiography should routinely be supplemented by sonography in the newborns and infants, if applicable. Brodie's abscess, which is clinically a subacute form of osteomyelitis, is best diagnosed by the combination of radiography and MRI. Chronic osteomyelitis is divided into primary haematogenous forms and exogenous, mostly post-traumatic, osteomyelitis. In the majority of patients, post-traumatic osteomyelitis is a clinical diagnosis; however, in a number of patients only the correlation of clinical findings, blood tests and imaging reveals the correct diagnosis. Often, MRI and scintigraphic methods, such as scanning with labeled leucocytes, together establish the diagnosis. Chronic recurrent multifocal osteomyelitis may mimic bacterial osteomyelitis but is a distinct disease probably associated with the SAPHO syndrome.

Soft tissue and joint infection

Soft tissue infection may be acute or chronic and may be introduced by the haematogenous route, or by inoculation, including surgical infection, or spread from other areas. The spectrum of infecting organism differs in primary infection, in immunodeficiency or when foreign bodies, including prostheses, are present. Bacterial infections are usually more rapid than those due to fungi or atypical organisms. Inflammation usually begins as cellulitis, proceeding through necrosis to cavitation and abscess formation, sometimes complicated by haemorrhage. Imaging, apart from MRI in selected cases, is rarely helpful in the early stages, but early diagnosis of pyomyositis and necrotizing fasciitis is mandatory. When infection is established, US, CT and MRI all have individual value in diagnosis, including biopsy, and in directing therapy, including percutaneous or surgical drainage or debridement. Both MRI and CT are best suited to monitoring progress. Septic arthritis presents as rapidly progressive, destructive arthritis, and early diagnosis is essential to prevent long-term morbidity. Ultrasound offers the best method of detecting early joint effusion and synovial thickening, but aspiration is usually required for diagnosis. In more advanced stages CT is valuable for revealing destructive changes, and MRI for documenting intra-articular changes and detecting inflammation in surrounding bone.

Disseminated Mycobacterium celatum infection in a white-tailed trogon (Trogon viridis)

An adult female white-tailed trogon (Trogon viridis) was presented with abdominal enlargement and hard subcutaneous masses. Necropsy findings included bony masses extending from skeletal structures, disseminated pale foci in the liver, and a pale mass in the kidney. Histological examination revealed multifocal to coalescing granulomatous inflammation in the bone, liver, kidney, lung and spleen. Mycobacterium celatum was isolated from the liver and identified by DNA sequencing. This is the first report of M. celatum infection in an avian species.

An in vitro study of adherence of coagulase-negative staphylococci to bone chip columns

Coagulase-negative staphylococci (CNS) have become a dominant cause of bone infections and their adherence to the infected bones is a prerequisite for the initiation of these infections. In the present study we investigated and compared the adherence of CNS bacteria to human, chicken and rabbit bones. The study was performed using columns made of bone powder from the three different sources, and measurement of the extent of adhesion to bones of CNS bacteria as an in vitro model which is based on particles of matrix that are closely related to the natural matrix. The adhesion to rabbit bone was relatively high, while adhesion to both human and chicken bone columns was lower and almost identical. Pretreatment of the CNS bacteria with sodium periodate, beta-galactosidase or proteinase K significantly inhibited by 50-60% the adhesion to human bones. Pretreatment of CNS bacteria with subinhibitory concentrations of vancomycin or tunicamycin increased their adherence to human bones several-fold. When the bones were pretreated with vancomycin a considerable increase in the adhesion rate of the bacteria to human and chicken bones was seen. A smaller increase in adherence was observed after pretreatment of human bones with the antibiotic tunicamycin. Salicylic acid or benzalkonium chloride (BZC) also resulted in an increase in adhesion to these pretreated bones. From the results obtained it seems that pretreatment of the CNS bacteria with certain reagents exposes adhesins on the surface of the CNS bacteria. On the other hand, pretreatment of the bones with other reagents may enable a better exposure of receptors located on the bone cells and, as a consequence, may improve the adhesion of the CNS bacteria to the treated bones.

Multifocal osteomyelitis in a child: a rare manifestation of cat scratch disease: a case report and systematic review of the literature

We present a case of a 9-year-old immunocompetent girl who presented with pain in her left elbow and a painful swelling at her left clavicle. She had no lymphadenopathy or fever. Four hot spots were seen at her left clavicle, proximal and distal left humerus and lumbo-sacral spine on a bone scan. A magnetic resonance imaging showed an inflammatory process with bone destruction at her clavicle. Serological testing and polymerase chain reaction performed on a bone biopsy identified a Bartonella henselae infection. She was treated with rifampin and trimethoprim-sulphamethoxazole. After a relapse half a year later, the patient recovered fully. Multifocal osteomyelitis is a rare manifestation of cat scratch disease in children.

The diagnosis of osteomyelitis of the foot in diabetes: microbiological examination vs. magnetic resonance imaging and labelled leucocyte scanning

AIMS

Foot infections and their sequelae are among the most common and severe complications of diabetes mellitus. As diabetic patients with foot infections develop osteomyelitis and may progress to amputation, early diagnosis of osteomyelitis is critical.

METHODS

We compared the diagnostic values of labelled leucocyte scanning with Tc(99)m, magnetic resonance imaging (MRI) and microbiological examination of bone tissue specimens with histopathology, the definitive diagnostic procedure. Thirty-one diabetic patients with foot lesions were enrolled in the study and histopathological examination was performed in all. Patients had clinically suspected foot lesions of > or = grade 3 according to the classification of Wagner.

RESULTS

Bone specimens were obtained for histopathological examination. Microbiology had a sensitivity of 92% and specificity of 60%. Labelled leucocyte scanning had a sensitivity of 91%, specificity of 67%, and MRI a sensitivity of 78%, specificity of 60%.

CONCLUSIONS

Microbiological examination may be as useful as and less costly than other diagnostic procedures and is the only method which can guide the choice of antibiotic therapy.

The effects of combined gentamicin-hydroxyapatite coating for cementless joint prostheses on the reduction of infection rates in a rabbit infection prophylaxis model

Infections remain a critical issue in total joint arthroplasty. Addition of antibiotics to bone cement was shown to significantly improve antimicrobial prophylaxis in cemented joint arthroplasty. In cementless joint arthroplasty a comparable prophylaxis by local antibiotics has not been possible yet. The aim of the current study was to investigate the antimicrobial effect of two different gentamicin-hydroxyapatite (HA) coatings for cementless prostheses in a rabbit infection model. Staphylococcus aureus with a dose of 10(7) CFUs was inoculated into the intramedullary canal of the tibia of 30 rabbits followed by the implantation of standard steel HA K-wires (n=10), steel K-wires coated with a gentamicin-HA combination (n=10), and steel K-wires coated with a gentamicin-RGD-HA combination (n=10), respectively. The animals were sacrificed after 28 days and clinical, histological and microbiological assessment on the bone and on the removed K-wire itself by agar plating and DNA-pulsed field gel electrophoresis were carried out to detect infection. There was a statistically significant reduction of infection rates by both gentamicin-coating types (0 infections in both groups) compared to standard HA coating (7 infections in 8 animals; 2 animals were lost due to acute diarrhea) (p<0.001). An excellent correlation between agar plating testing results of the K-wires and of the bone samples was found. Detailed histology showed cortical lysis, abscess and sequester formation in the infected animals. Both gentamicin-coating types showed significant improvement of infection prophylaxis compared to standard HA coating and, therefore, this coating technology could help to improve infection prophylaxis in cementless total joint arthroplasty. In further studies biocompatibility of the coatings has to be assessed.

A prospective evaluation of the diagnostic value of sinus specimen cultures in chronic osteomyelitis

We prospectively compared organisms isolated from sinus and bone marrow specimens in 25 patients with chronic osteomyelitis at the King Orthopaedic Clinic, Ekpoma, Edo State, Nigeria between January 2001 and December 2003. Sinus and bone marrow specimens were taken from each patient at the time of surgery and sent for aerobic cultures. The mean age was 12 years, with a range of 6-40 years. Staphylococcus aureus was the commonest organism associated with chronic osteomyelitis. Organisms isolated from the sinus specimens were similar to those obtained from the bone marrow specimens. Sinus specimen culture is a good guide to selection of antibiotics in the preoperative treatment of chronic osteomyelitis.

Evaluating bacterial pathogen DNA preservation in museum osteological collections

Reports of bacterial pathogen DNA sequences obtained from archaeological bone specimens raise the possibility of greatly improving our understanding of the history of infectious diseases. However, the survival of pathogen DNA over long time periods is poorly characterized, and scepticism remains about the reliability of these data. In order to explore the survival of bacterial pathogen DNA in bone specimens, we analysed samples from 59 eighteenth and twentieth century individuals known to have been infected with either Mycobacterium tuberculosis or Treponema pallidum. No reproducible evidence of surviving pathogen DNA was obtained, despite the use of extraction and PCR-amplification methods determined to be highly sensitive. These data suggest that previous studies need to be interpreted with caution, and we propose that a much greater emphasis is placed on understanding how pathogen DNA survives in archaeological material, and how its presence can be properly verified and used.

Etiologic diagnosis of chronic osteomyelitis: a prospective study

BACKGROUND

Although bone specimens were established 25 years ago as the gold standard for etiologic diagnosis of chronic osteomyelitis, recent studies suggest that nonbone specimens are as accurate as bone to identify the causative agent. We examined concordance rates between cultures from nonbone and bone specimens in 100 patients.

METHODS

Prospective study conducted at Hospital Universitario San Vicente de Paul, a 750-bed university-based hospital located in Medellín, Colombia. We included patients with chronic osteomyelitis who had been free of antibiotic therapy for at least 48 hours, excluding those with diabetic foot and decubitus ulcers. At least 1 nonbone and 1 bone specimen were taken from each individual and subjected to complete microbiologic analysis.

RESULTS

Bone cultures allowed agent identification in 94% of cases, including anaerobic bacteria in 14%. Cultures of nonbone and bone specimens gave identical results in 30% of patients, with slightly better concordance in chronic osteomyelitis caused by Staphylococcus aureus (42%) than by all other bacterial species (22%). However, statistical concordance determined by the Cohen kappa statistic was less than 0 (-0.0092+/-0.0324), indicating that the observed concordance was no better than that expected by chance alone (P>.99).

CONCLUSIONS

Appropriate diagnosis and therapy of chronic osteomyelitis require microbiologic cultures of the infected bone. Nonbone specimens are not valid for this purpose.

[Tuberculous osteoarthritis of the foot in the diabetic: not unrecognize this diagnostic trap. About one case]

Osteoarticular tuberculosis is the fourth leading extrapulmonary localization of tuberculosis. The disease has a progressive course and is often diagnosed in the stage of bone destruction, causing an important diagnostic problem in diabetics with nervous osteoarthropathy. We report the case of a 23-year-old patient with multicomplicated diabetes type 1, treated for pulmonary tuberculosis who consulted after a trauma distended the left ankle. Bone biopsy was performed because of the diagnostic doubt between diabetes and infectious osteoarthropathy. Pathology reported active tuberculosis. Osteoarticular tuberculosis is still a severe disease because of the functional prognosis that requires early diagnosis, a difficult task in some conditions particularly in the diabetic where the disease may mimic nervous osteoarthropathy. Bone biopsy should be performed if there is a doubt.

Endogeneous sources of infection in transplant recipients

The mammal organisms carry on their surfaces and in their tissues cohorts of microorganisms of various nature. There is a balance of interests and profits between the host and microbial inhabitants. The bacteria and fungi behave like comensals, colonizers, dormants, however, under certain, mostly unknown, conditions may evoke reaction of the host. This process is damaging both for the host and microbes. Large surgical trauma and allograft itself, as well as, immunosuppression create favorable conditions for imbalance between inhabiting microorganism and the recipient. The host flora and that transplanted with the organ graft become activated. Active combating of the proliferating bacteria with antibiotics becomes necessary. Our knowledge of the bacterial flora of the so called "sterile" tissues remains rudimentary. There is still a great deal of prejudice on the sterility of deep tissues e.g. muscles, fat tissue, etc. This review cumulates pertinent literature data on the microorganisms-host interactions. Our own findings on colonization of arteries and adjacent tissues are discussed in the context of atherosclerosis and grafting.

Evolutionary innovation: a bone-eating marine symbiosis

Symbiotic associations between microbes and invertebrates have resulted in some of the most unusual physiological and morphological adaptations that have evolved in the animal world. We document a new symbiosis between marine polychaetes of the genus Osedax and members of the bacterial group Oceanospirillales, known for heterotrophic degradation of complex organic compounds. These organisms were discovered living on the carcass of a grey whale at 2891 m depth in Monterey Canyon, off the coast of California. The mouthless and gutless worms are unique in their morphological specializations used to obtain nutrition from decomposing mammalian bones. Adult worms possess elaborate posterior root-like extensions that invade whale bone and contain bacteriocytes that house intracellular symbionts. Stable isotopes and fatty acid analyses suggest that these unusual endosymbionts are likely responsible for the nutrition of this locally abundant and reproductively prolific deep-sea worm.

Musculoskeletal tissue banking in Western Australia: review of the first ten years

BACKGROUND

Musculoskeletal tissue allotransplantation has been used as a standard approach for reconstructive surgery. The present study has reviewed the banking of musculoskeletal tissue at the Perth Bone and Tissue Bank (PBTB) and provided evidence of quality assurance on musculoskeletal tissue allotransplantation.

METHODS

All donor tissues were processed in accordance with the Therapeutic Goods Administration's relevant codes of good manufacturing practices. Microbiological monitoring at each step of manufacture and postoperative surveying of the musculoskeletal allotransplantations were both conducted. The possible contribution of contaminants in allografts to postoperative infections was also assessed.

RESULTS

Of the 5276 donors obtained over the last 10 years, 1672 were rejected, giving an overall donor rejection rate of 32%. Milled femoral heads were the most frequently implanted allografts, followed by whole femoral heads. In the postoperative survey an infection rate of 4.9% was found (113/2321 recipients). The infectious agents were identified in 65 cases but for 60 of these there were no correlations with the positive culture test results for the allografts. The organism most commonly identified in postoperative infections was Staphylococcus species.

CONCLUSIONS

The present study shows evidence that musculoskeletal tissue allotransplantation is a safe procedure when accompanied by high standards of quality assurance.

Genotypic analysis of the earliest known prehistoric case of tuberculosis in Britain

The earliest known case of human tuberculosis in Britain dates to the middle period of the Iron Age, approximately 2,200 years before present. Bone lesions on the spine of a male skeleton excavated at Tarrant Hinton in Dorset, United Kingdom, show evidence of Pott's disease and are supported by molecular evidence of Mycobacterium tuberculosis complex DNA amplified by IS6110 PCR (19). In the present study, we used a further series of sensitive PCR methods to confirm the diagnosis of tuberculosis and to determine the genotype of the infecting strain. These tests demonstrated that this individual was infected with a strain of M. tuberculosis rather than Mycobacterium bovis. The strain had undergone the tuberculosis D1 deletion affecting the mmpS6 and mmpL6 genes and can therefore be identified as a member of the family of "modern" M. tuberculosis isolates. All evidence obtained was consistent with surviving mycobacterial DNA being highly fragmented in this case.

Effective use of optimized, high-dose (50 kGy) gamma irradiation for pathogen inactivation of human bone allografts

The safety of tissue allografts has come under increased scrutiny due to recent reports of allograft-associated bacterial and viral infections in tissue recipients. We report that 50 kGy of gamma irradiation, nearly three times the dose currently used, is an effective pathogen inactivation method when used under optimized conditions that minimize damage to the tissue. Cancellous bone dowels treated with a radioprotectant solution and 50 kGy of optimized irradiation had an ultimate compressive strength and modulus of elasticity equal to conventionally irradiated (18 kGy) and non-irradiated control bone grafts. We subjected bone dowels treated with this pathogen inactivation method to an in vitro cytotoxicity test using three different mammalian cell lines and concluded that the treated grafts were not cytotoxic. The log reduction of nine pathogens spiked into radioprotectant-treated bone irradiated to 50 kGy was also tested. We achieved 4.9 logs of inactivation of a model virus for HIV and hepatitis C and 5 logs inactivation of a model virus for human parvovirus B-19. Complete inactivation (6.0-9.2 logs) of seven clinically relevant microorganisms was demonstrated. The results show that a combination of radioprotectants and optimized, high-dose gamma irradiation is a viable method for producing safer cancellous bone grafts that have the mechanical strength of existing grafts.

Development of heating method by microwave for sterilization of bone allografts

The purpose of this study was to develop a disinfection method using a microwave apparatus to treat large bone allografts. Heating of a bone allograft is an effective method for the disinfection of bacteria or inactivation of viruses. However, the size of the bone we can treat is limited, and following the popular method of using a bathtub is a lengthy process. The experimental system described here was designed using a microwave oven, an optical-fiber thermometer, and a power regulator. Large and small specimens, a femoral head, and a metatarsal were harvested from a bovine femur. The influence of size and the electrical or thermal characteristics of the specimens were assessed regarding temperature distribution after microwave irradiation. The effects of humidity or hot-air supply were also assessed. The average temperature of the bovine femoral head became 80 degrees C throughout the 15 min of microwave irradiation, although the temperature in the metatarsal did not attain uniformity. Microwave irradiation with a hot-air supply realized a uniform distribution of temperature at 83.0 degrees +/- 0.4 degrees C in the metatarsal within 15 min. Use of microwave irradiation enables quick heating for disinfection of large allograft bones when a hot-air supply was used as well.

Comparative metagenomics of microbial communities

The species complexity of microbial communities and challenges in culturing representative isolates make it difficult to obtain assembled genomes. Here we characterize and compare the metabolic capabilities of terrestrial and marine microbial communities using largely unassembled sequence data obtained by shotgun sequencing DNA isolated from the various environments. Quantitative gene content analysis reveals habitat-specific fingerprints that reflect known characteristics of the sampled environments. The identification of environment-specific genes through a gene-centric comparative analysis presents new opportunities for interpreting and diagnosing environments.