Comparison of Biolog GEN III MicroStation semi-automated bacterial identification system with matrix-assisted laser desorption ionization-time of flight mass spectrometry and 16S ribosomal RNA gene sequencing for the identification of bacteria of veterinary interest

Recent advances in phenotypic and chemotaxonomic methods have improved the ability of systems to resolve bacterial identities at the species level. Key to the effective use of these systems is the ability to draw upon databases which can be augmented with new data gleaned from atypical or novel isolates. In this study we compared the performance of the Biolog GEN III identification system (hereafter, GEN III) with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing in the identification of isolates of veterinary interest. The use of strains that had proven more difficult to identify by routine methods was designed to test the systems' abilities at the extremes of their performance range. Over an 18month period, 100 strains were analysed by all three methods. To highlight the importance of identification to species level, a weighted scoring system was devised to differentiate the capacity to identify at genus and species levels. The overall relative weighted scores were 0.869:0.781:0.769, achieved by 16S rRNA gene sequencing, GEN III and MALDI-TOF MS respectively, when compared to the 'gold standard'. Performance to the genus level was significantly better using 16S rRNA gene sequencing; however, performance to the species level was similar for all three systems.

Characterisation of Escherichia fergusonii isolates from farm animals using an Escherichia coli virulence gene array and tissue culture adherence assays

Escherichia fergusonii has been associated with a wide variety of intestinal and extra-intestinal infections in both humans and animals but, despite strong circumstantial evidence, the degree to which the organism is responsible for the pathologies identified remains uncertain. Thirty isolates of E. fergusonii collected between 2003 and 2004 were screened using an Escherichia coli virulence gene array to test for the presence of homologous virulence genes in E. fergusonii. The iss (increased serum survival) gene was present in 13/30 (43%) of the test strains and the prfB (P-related fimbriae regulatory) and ireA (siderophore receptor IreA) genes were also detected jointly in 3/30 (10%) strains. No known virulence genes were detected in 14/30 (47%) of strains. Following confirmatory PCR and sequence analysis, the E. fergusoniiprfB, iss and ireA genes shared a high degree of sequence similarity to their counterparts in E. coli, and a particular resemblance was noted with the E. coli strain APEC O1 pathogenicity island. In tissue culture adherence assays, nine E. fergusonii isolates associated with HEp-2 cells with a 'localised adherence' or 'diffuse adherence' phenotype, and they proved to be moderately invasive. The E. fergusonii isolates in this study possess both some phenotypic and genotypic features linked to known pathotypes of E. coli, and support existing evidence that strains of E. fergusonii may act as an opportunistic pathogens, although their specific virulence factors may need to be explored.

Tibio-femoral movement in the living knee. A study of weight bearing and non-weight bearing knee kinematics using 'interventional' MRI

The aim of this study was to image tibio-femoral movement during flexion in the living knee. Ten loaded male Caucasian knees were initially studied using MRI, and the relative tibio-femoral motions, through the full flexion arc in neutral tibial rotation, were measured. On knee flexion from hyperextension to 120 degrees , the lateral femoral condyle moved posteriorly 22 mm. From 120 degrees to full squatting there was another 10 mm of posterior translation, with the lateral femoral condyle appearing almost to sublux posteriorly. The medial femoral condyle demonstrated minimal posterior translation until 120 degrees . Thereafter, it moved 9 mm posteriorly to lie on the superior surface of the medial meniscal posterior horn. Thus, during flexion of the knee to 120 degrees , the femur rotated externally through an angle of 20 degrees . However, on flexion beyond 120 degrees , both femoral condyles moved posteriorly to a similar degree. The second part of this study investigated the effect of gender, side, load and longitudinal rotation. The pattern of relative tibio-femoral movement during knee flexion appears to be independent of gender and side. Femoral external rotation (or tibial internal rotation) occurs with knee flexion under loaded and unloaded conditions, but the magnitude of rotation is greater and occurs earlier on weight bearing. With flexion plus tibial internal rotation, the pattern of movement follows that in neutral. With flexion in tibial external rotation, the lateral femoral condyle adopts a more anterior position relative to the tibia and, particularly in the non-weight bearing knee, much of the femoral external rotation that occurs with flexion is reversed.

Magnetic resonance imaging-guided laser thermal ablation of renal tumours

OBJECTIVE

To test the hypothesis that magnetic resonance imaging (MRI)-guided laser thermal ablation (LTA) of inoperable renal tumours is a safe, tolerable and potentially effective treatment.

PATIENTS AND METHODS

Nine patients (aged 56-81 years) with malignant renal tumours underwent percutaneous LTA under MRI guidance in a 0.5 T open magnet. Real-time colour thermal mapping was used to monitor tumour ablation, and the follow-up was with gadolinium-enhanced MRI at 6 weeks and (where appropriate) 3-4 months after the procedure. Tumour volume and percentage tumour enhancement before and after ablation were compared. The percentage of tumour ablated on real-time T1-weighted thermal maps was compared with that on gadolinium-enhanced follow-up MRI.

RESULTS

The mean (range) follow-up was 16.9 (3-32) months after the first ablation. The mean tumour size did not change significantly, but the mean percentage of viable tumour decreased significantly from 73.7% before to 29.5% after ablation (P = 0.012, Wilcoxon signed-ranks test). Thermal maps correlated moderately well with follow-up MRI in predicting the extent of tumour ablation (Pearson correlation coefficient 0.55). There were two minor and one major complication.

CONCLUSION

In this pilot study of patients unsuitable for surgery, MRI-guided LTA of renal tumours was safe, feasible (being well tolerated by the patient) and significantly reduced enhancing tumour volume by a mean of 45%.

Can interventional MRI provide an insight into the mechanics of a posterior-anterior mobilisation?

OBJECTIVES

A pilot study aimed to investigate if interventional MRI could detect changes in the spine and surrounding soft tissues as a result of a posteroanterior mobilisation, and to determine if such an effect was specific to the level of application.

DESIGN

A prospective pilot study to investigate the kinematics of cervical spine mobilisation.

BACKGROUND

Posteroanterior mobilisation is a manual physiotherapy technique that is commonly used as an examination tool and a form of conservative treatment. The efficacy of this technique is controversial and little is known regarding the underlying mechanisms.

METHODS

Five control subjects were recruited and written informed consent obtained. Subjects were scanned, using a General Electric Signa SP10 Open Interventional MRI scanner, in the prone position with their necks in either a neutral or flexed position. In each position a posteroanterior mobilisation to the 2nd and 6th cervical vertebrae was performed. Sagittal images of the spine were obtained prior to, during and following the mobilisation.

RESULTS

Clear images of vertebral position could be obtained during the application of a posteroanterior mobilisation. Measurements of intervertebral angulation and translation demonstrated little if any motion during the application of a posteroanterior mobilisation, in both a flexed and neutral position. Changes were seen in terms of soft tissue compression and in some instances overall angulation of the cervical spine.

CONCLUSIONS

Interventional MRI can produce images of posteroanterior mobilisation. Dynamic imaging of the procedure produced images of unsuitable quality for analysis. The quasi-static images of suggested that the application of a posteroanterior mobilisation to the cervical spine produces minimal if any intervertebral motion, but significant soft tissue deformation of the overlying structures. RELEVANCE STATEMENT: Posteroanterior mobilisation is frequently used in the assessment and management of spinal problems, but the efficacy of the technique remains controversial. This is hampered by the fact that little is known about the mechanisms involved during such a procedure.

Ectodermal dysplasia in adulthood: the restorative difficulties and management

Ectodermal dysplasia can result in a number of oral problems. As the condition is usually diagnosed in childhood, multidisciplinary specialist dental care at an early age may minimize the long-term dental complications. This article describes the restorative management of an adult patient suffering from ectodermal dysplasia for whom such support was not available, resulting in the provision of complex and highly invasive restorative treatment in adult life to provide a functional and aesthetically acceptable dentition. The various treatment options that were considered are discussed together with the details of the treatment provided.

Case report: the advantage of close liaison between primary and secondary health workers in the restorative care of hemi-maxillectomy patients

The expansion of the maxillofacial speciality outside major teaching hospitals has not been mirrored by a similar expansion in Consultant-led restorative services. This has resulted in general dental practitioners being asked to provide both immediate and long-term restorative support for patients following surgery. Alternatively, the patient may have to travel long-distances to access specialist restorative advice. This paper describes the restorative management of a patient who, ten years after a hemi-maxillectomy, was referred to a Consultant in Restorative Dentistry for care. The treatment provided is detailed and the importance and benefit for the patient of close co-operation between the hospital and the general dental practitioner is highlighted.