Biofilm prevention concentration of clarithromycin against clinically relevant species of nontuberculous mycobacteria

OBJECTIVE

Mycobacterium avium complex (MAC) and Mycobacterium abscessus are a group of nontuberculous mycobacteria (NTM) that have been described as human pathogens. Their ability to develop biofilms in tissues and medical devices is one of the most important pathogenicity factors, with important implications in diagnosis and treatment. Macrolides are usually considered one of the bases of this treatment.

METHODS

Here we have studied the biofilm prevention concentration (BPC) of 16 strains (n=16) with clarithromycin to avoid the biofilm development by these NTM.

RESULTS

In this study, all M. abscessus strains have similar BPC, while MAC strains showed different values. For MAC the concentrations ranged between 1-16 mg/L, while for M. abscessus the concentration was 32 mg/L for all strains except one that was 64 mg/L.

CONCLUSIONS

These results open the possibility of using macrolides for the prevention of biofilm development in patients with a risk of developing NTM disease.

Positron Emission Tomography-Computed Tomography and Magnetic Resonance Imaging Assessments in a Mouse Model of Implant-Related Bone and Joint Staphylococcus aureus Infection

Osteomyelitis is an infection of the bone, associated with an inflammatory process. Imaging plays an important role in establishing the diagnosis and the most appropriate patient management. However, data are lacking regarding the use of preclinical molecular imaging techniques to assess osteomyelitis progression in experimental models. This study aimed to compare structural and molecular imaging to assess disease progression in a mouse model of implant-related bone and joint infections caused by Staphylococcus aureus. In SWISS mice, the right femur was implanted with a resorbable filament impregnated with S. aureus (infected group, n = 10) or sterile culture medium (uninfected group, n = 6). Eight animals (5 infected, 3 uninfected) were analyzed with magnetic resonance imaging (MRI) at 1, 2, and 3 weeks postintervention, and 8 mice were analyzed with [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)-computed tomography (CT) at 48 h and at 1, 2, and 3 weeks postintervention. In infected animals, CT showed bone lesion progression, mainly in the distal epiphysis, although some uninfected animals presented evident bone sequestra at 3 weeks. MRI showed a lesion in the articular area that persisted for 3 weeks in infected animals. This lesion was smaller and less evident in the uninfected group. At 48 h postintervention, FDG-PET showed higher joint uptake in the infected group than in the uninfected group (P = 0.025). Over time, the difference between groups increased. These results indicate that FDG-PET imaging was much more sensitive than MRI and CT for differentiating between infection and inflammation at early stages. FDG-PET clearly distinguished between infection and postsurgical bone healing (in uninfected animals) from 48 h to 3 weeks after implantation. IMPORTANCE Our results encourage future investigations on the utility of the model for testing different therapeutic procedures for osteomyelitis.

Antibiotic delivery from bone-targeted mesoporous silica nanoparticles for the treatment of osteomyelitis caused by methicillin-resistant Staphylococcus aureus

Osteomyelitis is a hard-to-treat infection of the bone and bone marrow that is mainly caused by Staphylococcus aureus, with an increasing incidence of methicillin-resistant S. aureus (MRSA). Owing to the aggressiveness of these bacteria in colonizing and destroying the bone, systemic antibiotic treatments fail to eradicate the infection. Instead, it normally entails surgery to remove the dead or infected bone. In this work, we report bone-targeted mesoporous silica nanoparticles for the treatment of osteomyelitis. The nanoparticles have been engineered with a functional gelatine/colistin coating able to hamper premature release from the mesopores while effectively disaggregating the bacterial biofilm. Because antibiotic resistance is a global emergency, we have designed two sets of identical nanoparticles, carrying each of them a clinically relevant antibiotic, that have demonstrated to have synergistic effect. The bone-targeted nanoparticles have been thoroughly evaluated in vitro and in vivo, obtaining a notable reduction of the amount of bacteria in the bone in just 24 h after only one dose, and paving the way for localized, nanoparticle-mediated treatment of MRSA-caused osteomyelitis. STATEMENT OF SIGNIFICANCE: In this work, we propose the use of bone-targeted mesoporous silica nanoparticles to address S. aureus-caused osteomyelitis that render synergistic therapeutic effect via multidrug delivery. Because the bacterial biofilm is responsible for an aggressive surgical approach and prolonged antibiotic treatment, the nanoparticles have been functionalized with a functional coating able to both disaggregate the biofilm, hamper premature antibiotic release and protect the intact bone. These engineered nanoparticles are able to effectively target bone tissue both in vitro and in vivo, showing high biocompatibility and elevated antibacterial effect.

Barriers and facilitators in the implementation of a telemedicine-based outpatient brain tumor surgery program

OBJECTIVE

Despite growing evidence on the benefits of outpatient oncological neurosurgery (OON), it is only performed in a few specialized centers and there are no previous descriptions of established OON programs in Europe. Moreover, increasing application of telemedicine strategies, especially after the start of the coronavirus disease 2019 (COVID-19) pandemic, is drastically changing neurosurgical management, particularly in the case of vulnerable populations such as neuro-oncological patients. In this context, the authors implemented an OON program in their hospital with telematic follow-up. Herein, they describe the protocol and qualitatively analyze the barriers and facilitators of the development process.

METHODS

An OON program was developed through the following steps: assessment of hospital needs, specific OON training, multidisciplinary team organization, and OON protocol design. In addition, the implementation phase included training sessions, a pilot study, and continuous improvement sessions. Finally, barriers and facilitators of the protocol’s implementation were identified from the feedback of all participants.

RESULTS

An OON protocol was successfully designed and implemented for resection or biopsy of supratentorial lesions up to 3 cm in diameter. The protocol included the patient’s admission to the day surgery unit, noninvasive anesthetic monitoring, same-day discharge, and admission to the hospital-at-home (HaH) unit for telematic and on-site postoperative care. After a pilot study including 10 procedures in 9 patients, the main barriers identified were healthcare provider resistance to change, lack of experience in outpatient neurosurgery, patient reluctance, and limitations in the recruitment of patients. Key facilitators of the process were the patient education program, the multidisciplinary team approach, and the HaH-based telematic postoperative care.

CONCLUSIONS

Initiating an OON program with telematic follow-up in a European clinical setting is feasible. Nevertheless, it poses several barriers that can be overcome by identifying and maximizing key facilitators of the process. Among them, patient education, a multidisciplinary team approach, and HaH-based postoperative care were crucial to the success of the program. Future studies should investigate the cost-effectiveness of telemedicine to assess potential cost savings, from reduced travel and wait times, and the impact on patient satisfaction.

Arabic gum plus colistin coated moxifloxacin-loaded nanoparticles for the treatment of bone infection caused by Escherichia coli

Osteomyelitis is an inflammatory process of bone and bone marrow that may even lead to patient death. Even though this disease is mainly caused by Gram-positive organisms, the proportion of bone infections caused by Gram-negative bacteria, such as Escherichia coli, has significantly increased in recent years. In this work, mesoporous silica nanoparticles have been employed as platform to engineer a nanomedicine able to eradicate E. coli- related bone infections. For that purpose, the nanoparticles have been loaded with moxifloxacin and further functionalized with Arabic gum and colistin (AG+CO-coated MX-loaded MSNs). The nanosystem demonstrated high affinity toward E. coli biofilm matrix, thanks to AG coating, and marked antibacterial effect because of the bactericidal effect of moxifloxacin and the disaggregating effect of colistin. AG+CO-coated MX-loaded MSNs were able to eradicate the infection developed on a trabecular bone in vitro and showed pronounced antibacterial efficacy in vivo against an osteomyelitis provoked by E. coli. Furthermore, AG+CO-coated MX-loaded MSNs were shown to be essentially non-cytotoxic with only slight effect on cell proliferation and mild hepatotoxicity, which might be attributed to the nature of both antibiotics. In view of these results, these nanoparticles may be considered as a promising treatment for bone infections caused by enterobacteria, such as E. coli, and introduce a general strategy against bone infections based on the implementation of antibiotics with different but complementary activity into a single nanocarrier. STATEMENT OF SIGNIFICANCE: In this work, we propose a methodology to address E.coli bone infections by using moxifloxacin-loaded mesoporous silica nanoparticles coated with Arabic gum containing colistin (AG+CO-coated MX-loaded MSNs). The in vitro evaluation of this nanosystem demonstrated high affinity toward E. coli biofilm matrix thanks to the Arabic gum coating, a disaggregating and antibacterial effect of colistin, and a remarkable antibiofilm action because of the bactericidal ability of moxifloxacin and colistin. This anti-E. coli capacity of AG+CO-coated MX-loaded MSNs was brought out in an in vivo rabbit model of osteomyelitis where the nanosystem was able to eradicate more than 90% of the bacterial load within the infected bone.

Transopercular Insular Approach, Overcoming the Training Curve Using a Cadaveric Simulation Model: 2-Dimensional Operative Video

Transopercular approach to the insula is indicated for resection of insular low-grade gliomas, particularly for Yasargil's 3B, 5A, and 5B types. Nevertheless, the infrequent location and its challenging approach make it difficult to master the surgery. Consequently, a realistic laboratory training model might help to acquire key surgical skills. In this video, we describe a cadaveric-based model simulating the resection of a temporo-insular low-grade glioma. Kingler's fixation technique was used to fix the cadaver head before injecting red and blue colorants for a realistic vascular appearance. Hemisphere was frozen for white matter tract dissection. Tractography and intraoperative eloquent areas were extrapolated from a glioma patient by using a neuronavigation system. Then, a fronto-temporal craniotomy was performed through a question mark incision, exposing from inferior temporal gyrus up to middle frontal gyrus. After cortical anatomic landmark identification, eloquent areas were extrapolated creating a simulated functional cortical map. Then, transopercular noneloquent frontal and temporal corticectomies were performed, followed by subpial resection. Detailed identification of Sylvian vessels and insular cortex was demonstrated. Anatomic resection limits were exposed, and implicated white matter bundles, uncinate and fronto-occipital fascicles, were identified running through the temporal isthmus. Finally, a temporo-mesial resection was performed. In summary, this model provides a simple, cost-effective, and very realistic simulation of a transopercular approach to the insula, allowing the development of surgical skills needed to treat insular tumors in a safe environment. Besides, the integration of simulated navigation has proven useful in better understanding the complex white matter anatomy involved. Cadaver donation, subject or relatives, includes full consent for publication of the images. For the purpose of this video, no ethics committee approval was needed. Images correspond to a cadaver head donation. Cadaver donation, subject or relatives, includes full consent for any scientific purposes involving the corpse. The consent includes image or video recording. Regarding the intraoperative surgical video and tractography, the patient gave written consent for scientific divulgation prior to surgery.

When genetic and surname analyses meet historical sources: The C56R mutation associated with factor XI deficiency as a marker of human migration during the Spanish Reconquista

The C56R mutation associated with factor XI deficiency has been first evidenced in individuals from the French Basque Country. Genetic investigations revealed that this mutation occurred about 5400 years ago as a founder effect in this zone. Other cases were subsequently described in Southwestern Europe. Noticeably a cluster of cases was evidenced in Yecla, a small city from the province of Murcia, in Southeastern Spain. In correlation with historical sources our genetic data and surname analysis argue for associating this mutation with the migration of people from Western Pyrenees (and more probably from the Navarra province) toward Southeastern Spain during the Reconquista period.

Functionalization of sol-gel coatings with organophosphorus compounds for prosthetic devices

Sol-gel coatings are proposed as surface treatments for titanium-based materials to promote the osseointegration of prosthetic devices with the host. As precursors of sol-gel synthesis, two silanes were selected: 3-methacryloxypropyltrimethoxy silane and 2 tetramethyl orthosilane. Sol-gel synthesis was functionalized with the addition of two different organophosphorus compounds, namely, tris(trimethylsilyl) phosphite and tris(trimethylsilyl) phosphate. Depending on the organophosphorus compound, phosphorus was incorporated into the sol-gel network by different mechanisms: organophosphate was incorporated following a hydrolysis/polycondensation reaction with the precursors of synthesis (two organopolysiloxanes), whereas organophosphite was introduced into the network through transformation of trivalent phosphorus to pentavalent phosphorus following a Michaelis-Arbuzov reaction and subsequent reaction of hydrolysis/polycondensation. When compared to the control coating, which has good adhesion coating-substrate, only the addition of the organophosphite ensured good adhesion without altering synthesis. The resulting coating modified with organophosphite was subjected to cellular study and the concentration of this compound was varied to reach the highest enhancement of proliferation. It was demonstrated that by increasing the amount of organophosphite cell proliferation increased. Inspection of the surfaces of the coatings revealed that by increasing the quantity of organophosphite, adhesion to the substrate was compromised. Thus, an intermediate quantity of organophosphite was considered the most suitable for application on metallic prosthetic devices.

High incidence of FXI deficiency in a Spanish town caused by 11 different mutations and the first duplication of F11: Results from the Yecla study

INTRODUCTION

Factor XI (FXI) deficiency is a rare disorder with molecular heterogeneity in Caucasians but relatively frequent and molecularly homogeneous in certain populations.

AIM

To characterize FXI deficiency in a Spanish town of 60 000 inhabitants.

METHODS

A total of 324 764 APTT tests were screened during 20 years. FXI was evaluated by FXI:C and by Western blot. Genetic analysis of F11 was performed by sequencing, multiplex ligation-dependent probe amplification and genotyping.

RESULTS

Our study identified 46 unrelated cases and 170 relatives with FXI deficiency carrying 12 different genetic defects. p.Cys56Arg, described as founder mutation in the French-Basque population, was identified in 109 subjects from 24 unrelated families. This mutation was also identified in 2% of the general population. p.Cys416Tyr, c.1693G>A and p.Pro538Leu were identified in 7, 6 and 2 unrelated families, respectively. NGS analysis of the whole F11 gene revealed a common haplotype for each of the four recurrent mutations, suggesting a founder effect. The analysis of plasma FXI of four p.Pro538Leu homozygous carriers revealed that this variant was not activated by FXIIa. We identified four mutations previously described in other Caucasian subjects with FXI deficiency (p.Lys536Asn; p.Thr322Ile, p.Arg268Cys and c.325G>A) and four new gene defects: p.(Cys599Tyr) potentially causing a functional deficiency, p.(Ile426Thr), p.(Ile592Thr) and the first worldwide duplication of 1653 bp involving exons 8 and 9. Bleeding was rare and mild.

CONCLUSIONS

Our population-cohort study supplies new evidences that FXI deficiency in Caucasians is more common than previously thought and confirmed the wide underlying genetic heterogeneity, caused by both recurrent and sporadic mutations.

Evaluation of bacterial adherence of clinical isolates of Staphylococcus sp. using a competitive model: An in vitro approach to the "race for the surface" theory

Objectives

Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the in vitro studies did not evaluate bacterial adhesion in the presence of eukaryotic cells, as stated by the ‘race for the surface’ theory. Moreover, the adherence of numerous clinical strains with different initial concentrations has not been studied.

Methods

We describe a method for the study of bacterial adherence in the presence of preosteoblastic cells. For this purpose we mixed different concentrations of bacterial cells from collection and clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells, and analysed the minimal concentration of bacteria able to colonise the surface of the material with image analysis.

Results

Our results show that clinical strains adhere to the material surface at lower concentrations than collection strains. A destructive effect of bacteria on preosteoblastic cells was also detected, especially with higher concentrations of bacteria.

Conclusions

The method described herein can be used to evaluate the effect of surface modifications on bacterial adherence more accurately than conventional monoculture studies. Clinical strains behave differently than collection strains with respect to bacterial adherence.

Cite this article: M. Martinez-Perez, C. Perez-Jorge, D. Lozano, S. Portal-Nuñez, R. Perez-Tanoira, A. Conde, M. A. Arenas, J. M. Hernandez-Lopez, J. J. de Damborenea, E. Gomez-Barrena, P. Esbrit, J. Esteban. Evaluation of bacterial adherence of clinical isolates of Staphylococcus sp. using a competitive model: An in vitro approach to the “race for the surface” theory. Bone Joint Res 2017;6:315–322. DOI: 10.1302/2046-3758.65.BJR-2016-0226.R2.

Time trends in the aetiology of prosthetic joint infections: a multicentre cohort study

It is important to know the spectrum of the microbial aetiology of prosthetic joint infections (PJIs) to guide empiric treatment and establish antimicrobial prophylaxis in joint replacements. There are no available data based on large contemporary patient cohorts. We sought to characterize the causative pathogens of PJIs and to evaluate trends in the microbial aetiology. We hypothesized that the frequency of antimicrobial-resistant organisms in PJIs has increased in the recent years. We performed a cohort study in 19 hospitals in Spain, from 2003 to 2012. For each 2-year period (2003-2004 to 2011-2012), the incidence of microorganisms causing PJIs and multidrug-resistant bacteria was assessed. Temporal trends over the study period were evaluated. We included 2524 consecutive adult patients with a diagnosis of PJI. A microbiological diagnosis was obtained for 2288 cases (90.6%). Staphylococci were the most common cause of infection (1492, 65.2%). However, a statistically significant rising linear trend was observed for the proportion of infections caused by Gram-negative bacilli, mainly due to the increase in the last 2-year period (25% in 2003-2004, 33.3% in 2011-2012; p 0.024 for trend). No particular species contributed disproportionally to this overall increase. The percentage of multidrug-resistant bacteria PJIs increased from 9.3% in 2003-2004 to 15.8% in 2011-2012 (p 0.008), mainly because of the significant rise in multidrug-resistant Gram-negative bacilli (from 5.3% in 2003-2004 to 8.2% in 2011-2012; p 0.032). The observed trends have important implications for the management of PJIs and prophylaxis in joint replacements.

A severe case of Hirayama disease successfully treated by anterior cervical fusion

Hirayama disease, or juvenile amyotrophy of distal upper extremity, is a benign, self-limiting cervical myelopathy consisting of selective unilateral weakness of the hand and forearm. The weakness slowly progresses until spontaneous arrest occurs within 5 years of onset. The condition predominantly affects Asian males and is thought to be secondary to spinal cord compression during neck flexion, because of a forward displacement of the posterior dural sac.

The authors present what is to their knowledge the first reported case of a Caucasian male with a severe form of Hirayama disease, suffering from weakness of the leg as well as the forearm. An abnormal range of cervical flexion was observed at the C5–6 level. The patient was successfully treated by anterior cervical discectomy and fusion.

Prolonged incubation time does not increase sensitivity for the diagnosis of implant-related infection using samples prepared by sonication of the implants

We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period.

Cite this article: Bone Joint J 2013;95-B:1001–6.

Risk factors and clinical significance of invasive infections caused by levofloxacin-resistant Streptococcus pneumoniae

Purpose

Fluoroquinolones are recommended for the treatment of pneumonia. The recognition of risk factors for invasive levofloxacin-resistant Streptococcus pneumoniae is important for the design of treatment.

Methods

A retrospective review of cases of invasive pneumococcal infections in adults was undertaken. Epidemiologic data, predisposing factors, clinical variables, and outcome were recorded from previously established protocols. Antimicrobial susceptibility was determined by disk diffusion and the Etest method. Serotyping was performed by latex agglutination and Quellung reaction.

Results

Twenty patients with infection caused by levofloxacin-resistant pneumococci [minimum inhibitory concentration (MIC) ≥2 μg/ml] were compared with 102 patients harboring levofloxacin-susceptible strains; 80 % of levofloxacin-resistant pneumococci were resistant to ≥3 antibiotics but susceptible to penicillin. Most levofloxacin-resistant strains (80 %) belonged to serotype 8. In comparison, only 8 % of levofloxacin-susceptible pneumococci belonged to serotype 8. In the multivariate analysis, residence in public shelters [odds ratio (OR) 26.13; p 0.002], previous hospitalization (OR 61.77; p < 0.001), human immunodeficiency virus (HIV) infection (OR 28.14; p = 0.009), and heavy smoking (OR 14.41; p = 0.016) were associated with an increased risk of infection by levofloxacin-resistant pneumococci. Mortality caused by levofloxacin-resistant and levofloxacin-susceptible pneumococci was 35 and 14 %, respectively. Among HIV-positive individuals infected with levofloxacin-resistant pneumococci 44 % died, but only 12.5 % of HIV-positive patients with levofloxacin-susceptible strains died.

Conclusions

We observed the emergence of serotype 8 as the main cause of invasive disease caused by levofloxacin-resistant S. pneumoniae. HIV-positive patients seem to be prone to infection caused by multidrug-resistant serotype 8 and have a high mortality rate.

Mycobacterium africanum, an emerging disease in high-income countries?

BACKGROUND

Mycobacterium africanum is a cause of tuberculosis (TB) that has mainly been described in Africa, but immigration and travel patterns have contributed to the spread of the disease to other countries.

METHODS

We retrospectively reviewed TB cases due to M. africanum during 2000-2010 in seven Spanish hospitals. Selected clinical charts were reviewed using a predefined protocol that included demographical, clinical and microbiological data and outcome.

RESULTS

Although 57 cases were diagnosed, only 36 clinical charts were available for review: 82.8% were men and the mean age was 31.6 years (range 12-81). Forty-four cases were from Africa, 1 from the Philippines, 1 from India, and 4 from Spain, while the country of origin was unknown in 7 cases. The most frequent site of infection was the lung (58.3%). Four cases (6.9%) were resistant to at least one first-line anti-tuberculosis drug.

CONCLUSIONS

Disease due to M. africanum in industrialised countries is mainly associated with immigration from endemic areas, although some cases also occur among native-born populations.

Sonication of intramedullary nails: clinically-related infection and contamination

BACKGROUND AND AIM

Sonication is currently considered the best procedure for microbiological diagnosis of implant-related osteoarticular infection, but studies in nail-related infections are lacking. The study aim was to evaluate implant sonication after intramedullary nail explantation, and relate it to microbiological cultures and clinical outcome.

PATIENTS AND METHODS

A study was performed in two University Hospitals from the same city. Thirty-one patients with implanted nails were prospectively included, whether with clinical infection (8 cases) or without (23 cases). Retrieved nails underwent sonication according a previously published protocol. The clinical and microbiological outcome patient was related to the presence of microorganisms in the retrieved implant.

RESULTS

Positive results appeared in 15/31 patients (9 with polymicrobial infections) almost doubling those clinically infected cases. The most commonly isolated organisms were Staphylococcus epidermidis (19.2 %) and Staphylococcus aureus (15.4 %). A significant relationship was found between the presence of positive cultures and previous local superficial infection (p=0.019). The presence of usual pathogens was significantly related to clinical infection (p=0.005) or local superficial infection (p=0.032). All patients with positive cultures showed pain diminution or absence of pain after nail removal (15/15), but this only occurred in 8 (out of 16) patients with negative cultures.

CONCLUSIONS

In patients with previously diagnosed infection or local superficial infection, study of the hardware is mandatory. In cases where pain or patient discomfort is observed, nail sonication can help diagnose the implant colonization with potential pathogens that might require specific treatment to improve the final outcome.

SPG7 mutational screening in spastic paraplegia patients supports a dominant effect for some mutations and a pathogenic role for p.A510V

Mutations in the SPG7 gene were initially reported in patients with autosomal recessive hereditary spastic paraplegia (HSP). Recent works suggested a dominant effect for some SPG7 mutations. To characterize the SPG7 mutational spectrum in a large cohort of Spanish HSP patients, we sequenced the whole SPG7 gene in a total of 285 Spastic Paraplegia patients. Large gene rearrangements were also ascertained in some patients. We found a total of 14 SPG7 mutations (12 new) in 14 patients; 2 were large deletions. All the mutation carriers had an adult onset age but only five (35%) had a complicated phenotype. We identified a single mutation in 13 patients. Familial analysis suggested a dominant inheritance for one (p.Leu78*) of these mutations. Carriers of the rare p.A510V variant were significantly more frequent in patients vs healthy controls (3% vs 1%), suggesting a pathogenic role for this SPG7 variant. We reported a high frequency of patients with only one SPG7 mutation, and a putative pathogenic role for the p.A510V variant.

Evaluation of the detection of Mycobacterium tuberculosis with metabolic activity in culture-negative human clinical samples

Mycobacterium tuberculosis is assumed to remain in a quiescent state during latent infection, being unable to grow in culture. The aim of this study was to evaluate the detection of viable but non-cultivable bacilli with metabolic activity in human clinical samples using a procedure that is independent of the immunological status of the patient. The study was performed on 66 human clinical samples, from patients subjected to routine diagnosis to rule out a mycobacterial infection. Specimens from pulmonary and extra-pulmonary origins were verified to contain human DNA before testing for M. tuberculosis DNA, rRNA and transient RNA by real-time quantitative PCR. Clinical records of 55 patients were also reviewed. We were able to detect viable but non-cultivable bacilli with a metabolic activity in both pulmonary and extra-pulmonary samples. Mycobacterium tuberculosis RNA was detected in the majority of culture-positive samples whereas it was detected in one-third of culture-negative samples, 20% of them showed metabolic activity. Amplifications of the ftsZ gene and particularly of the main promoter of the ribosomal operon rrnA, namely PCL1, seem to be good targets to detect active bacilli putatively involved in latent infection. Moreover, this last target would provide information on the basal metabolic activity of the bacilli detected.

PD03-09: Breast Cancer Recurrence Risk Probed by Whole Transcriptome Next Generation Sequencing in 136 Patients

Background: RNA biomarkers discovered by RT-PCR-based gene expression profiling of archival formalin-fixed paraffin-embedded (FFPE) tissue are the basis for very precise and sensitive clinical diagnostic tests, such as the 21 gene Oncotype DX® breast cancer assay. Both inherent limits of technical scalability and the small amounts of patient FFPE RNA available place practical constraints on the number of transcripts that can be interrogated by RT-PCR. We developed new methods for RNA profiling through massively parallel “next generation” sequencing (RNA-Seq) of archival FFPE specimens. We report here the technical performance of this methodology and compare the results to RT-PCR results obtained in one of the studies that were carried out to develop the 21 gene assay.

Methods: RNA was extracted in 2002 from 136 invasive breast tumors that were formalin-fixed and paraffin-embedded between 1990 and 1997. RNA-Seq was carried out using minor modifications to methods we have reported previously (Sinicropi et al., Advances in Genome Biology and Technology Conference, p. 170, 2010 and p. 198, 2011). Briefly, 0.1 mg of total RNA was selectively depleted of ribosomal RNA and sequencing libraries were prepared using a modification of the ScriptSeq™ kit from Epicentre. The libraries were sequenced on an Illumina HiSeq 2000 instrument with multiplexing of two libraries per lane for 50 cycles in one direction. The resulting FASTQ sequences were mapped to version hg19 of the human genome using the Illumina CASAVA pipeline. The total number of sequences (reads) that uniquely mapped to all exons of each RefSeq entry was used for quantification of expression levels.

Results: On average, there were 43 million reads per sample (range 31 - 58 million; SD=4.6 million) of which 69% uniquely mapped to the human genome. Ribosomal RNA was effectively removed and accounted for &lt;0.3% of total counts. Significant coverage of a high proportion of the human genome was obtained, with 40% of RefSeq transcripts represented by a median of more than 100 reads. Using Cox proportional hazards analysis to evaluate the association of quantitative gene expression with breast cancer recurrence, the standardized hazard ratios and p-values for the 21 Oncotype DX genes determined by RNA-Seq were comparable to those originally obtained using RT-PCR. Moreover, whole transcriptome RNA-Seq identified more than 1800 new coding, intronic, and intergenic transcripts that strongly associated with breast cancer recurrence risk (at a false discovery rate &lt;10%) and revealed heretofore unappreciated co-expressed gene networks. Summary: New methodology has been developed for application of next generation sequencing-based whole transcriptome profiling to small amounts of archival FFPE tissue. This technology has sensitivity and selectivity comparable to RT-PCR, can provide a vast increase in the number of interrogated transcripts, can reveal new biological relationships, and has excellent performance suitable for the discovery of RNA biomarkers.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD03-09.

Bacterial adherence on UHMWPE with vitamin E: an in vitro study

Orthopaedic materials may improve its capacity to resist bacterial adherence, and subsequent infection. Our aim was to test the bacterial adherence to alpha-tocopherol (frequently named vitamin E, VE) doped or blended UHMWPE with S. aureus and S. epidermidis, compared to virgin material. Collection strains and clinical strains isolated from patients with orthopaedic infections were used, with the biofilm-developing ability as a covariable. While collection strains showed significantly less adherence to VE-UHMWPE, some clinical strains failed to confirm this effect, leading to the conclusion that VE doped or blended UHMWPE affects the adherence of some S. epidermidis and S. aureus strains, independently of the concentration in use, but the results showed important intraspecies differences and cannot be generalized.

Predictors of influenza vaccination uptake among adults with a history of heart attack

BACKGROUND

Influenza vaccination can reduce morbidity and mortality caused by cardiovascular diseases. This study sought to evaluate influenza vaccination coverage among adults with a history of heart attack and to determine which variables were associated with vaccine uptake.

RESULTS

A total of 716 adults reported having suffered a heart attack. The coverage among sufferers was 67.9% as against 35% for non sufferers. The variables that were significantly associated with a higher likelihood of receiving the vaccine among sufferers were: higher age; male gender, no smoking habit, "Physician visits in the preceding four weeks"; and, "Blood pressure control in the preceding three months".

DESIGN

A descriptive study was conducted using individual data from adults aged ≥40 years included in the year 2006/7 Spanish Health Survey and comparing subjects with a history of heart attack with those who had not suffered this event.

METHODS

The number of participants surveyed was 20,060. Subjects were classified as heart attack sufferers if they answered affirmatively to the question: "Has your doctor told you that you have suffered a heart attack?" To assess influenza vaccination status we considered the response to the question, "Did you have a 'flu shot in the latest campaign?". Independent variables included sociodemographic, health-related, lifestyles and periodic control of cardiovascular risk factors.

CONCLUSIONS

Influenza vaccination coverage among subjects who have suffered a heart attack is below desirable levels. Multiple strategies focused on providers and patients are needed to improve influenza vaccination coverage among these high risk subjects, particularly now with the emerging H1N1 pandemic.

[SOD1-N196 mutation in a family with amyotrophic lateral sclerosis]

INTRODUCTION

N19S mutation is produced by substitution in the 139 position of SOD1 and was described by Mayeux in a patient with amyotrophic lateral sclerosis (ALS). He suggested that it did not have a causal effect as it was found in asymptomatic and sporadic cases. Other authors in later articles did not agree.

MATERIAL AND METHODS

We describe a family with 4 members with ALS patients and attempt to find the carrier of the N19S mutation of the propositus. Molecular studies were performed on 15 members of the family of a different order.

RESULTS

The ALS cases were found in the maternal line of the propositus. The presence of the mutation was detected in 3 people, the other two were asymptomatic. One of patients with ALS in the family, who died previously, did not have the mutation. Two of the sons of this case and another of the other case did not show it. On the other hand, N19S mutation was only present in paternal branch of the propositus, where there were no cases.

CONCLUSION

The described family supports the hypothesis by Mayeux and against that mutation N19S has pathological consequences, since mutation is only in the family line where there are no cases with ALS. In consequence, although the described case is included as a familiar form, it cannot be attributed to the mutation, and its relationship with N19S should be considered as casual.

Effect of Secondary Phases Formation in the Leaching of UO2 Under Simulated Radiolytic Products

The leaching of the spent fuel matrix (UO2) is function of the radiolytic products formation. The effect of each radioiytic product on the leaching process is not totally understood. In the literature, the influence of H2O2 on the dissolution process is described from the qualitative point of view, and most of the studies were performed for pH values from 8 to 12. In this paper we report on the effect of the H2O2 in the leaching process of UO2 by dissolution experiments at various H2O2 concentrations. Also, it was tested the influence of S/V ratio (surface area exposed to the leaching media) on the UO2 leaching and secondary phases formation. It was identified the formation of secondary phases on the UO2 surface. Solid phases characterization was carried out by x-ray Photoelectron Spectrometry (XPS), x-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. By XPS studies the secondary phase formed corresponded to a U(VI) phase. By XRD analyses the solid was identified as studtite, UO4 - 4H2O, (card n0 16–206, [I]). A comparison of the U(VI) phases formed in spent fuel and UO, leaching experiments in various media has been carried out.

A case of Hirayama disease treated with laminectomy and duraplasty without spinal fusion

INTRODUCTION

Juvenile amyotrophy of the distal upper extremity (JADUE) is a rare disease afecting young males. Since neck flexion has been thought to be the cause of the spinal cord damage, cervical orthosis, spinal fusion by an anterior or posterior approach and duraplasty in combination with posterior spinal fusion have been proposed as treatment of JADUE. We are presenting the case of a patient with JADUE who was surgically treated with duraplasty without spinal fusion, thus avoiding the compression of the spinal cord without limitation of cervical movement.

CASE

A previously healthy 19-year-old man presented with insidious onset of weakness in the left forearm and hand for the past year. On MRI, during neck flexion, the posterior dura showed anterior displacement that compressed the cervical spinal cord. The dura was opened linearly from C3 to C6, observing the herniation of the spinal cord through the opening. Duraplasty was performed in order to increase the room of the spinal cord. No spinal fusion was performed.

DISCUSSION

The postoperative course was uneventful. Clinical deterioration stopped following operation and two years later unchanged as compared to the preoperative one.