Genome sequencing and molecular characterisation of Staphylococcus aureus ST772-MRSA-V, “Bengal Bay Clone”

Background: The PVL-positive ST772-MRSA-V is an emerging community-associated (CA-) MRSA clone that has been named Bengal Bay Clone since most patients have epidemiological connections to the Indian subcontinent. It is found increasingly common in other areas of the world. Methods: One isolate of ST772-MRSA-V was sequenced using the Illumina Genome Analyzer System. After initial assembling the multiple sequence contigs were analysed using different in-house annotation scripts. Results were compared to microarray hybridisation results of clinical isolates of ST772-MRSA-V, of related strains and to another ST772-MRSA-V genome sequence. Results: According to MLST e-burst analysis, ST772-MRSA-V belongs to Clonal Complex (CC)1, differing from ST1 only in one MLST allele (pta-22). However, there are several additional differences including agr alleles (group II rather than III), capsule type (5 rather than 8), the presence of the egc enterotoxin gene cluster and of the enterotoxin homologue ORF CM14 as well as the absence of the enterotoxin H gene seh. Enterotoxin genes sec and sel are present. ST772-MRSA-V harbours the genes encoding enterotoxin A (sea) and PVL (lukS/F-PV). Both are located on the same prophage. Conclusions: ST772-MRSA-V may have emerged from the same lineage as globally spread CC1 and CC5 strains. It has acquired a variety of virulence factors, and for a CA-MRSA strain it has an unusually high number of genes associated with antibiotic resistance

Long-term correlations and fractal dimension of beat-to-beat blood pressure dynamics

© World Scientific Publishing CompanyArterial blood pressure is modulated by several physiological regulatory processes. The analysis of beat-to-beat blood pressure dynamics provides information about cardiovascular control and patho-physiological conditions. In this paper we investigated the long-term correlations and fractal dimension of systolic blood pressure time series applying detrended fluctuation analysis (DFA) and Higuchi's algorithm (HFD). Thirty-minute blood pressure recordings in 25 patients with dilated cardiomyopathy (DCM) and 27 healthy controls (CON) were analyzed. The DFA and HFD revealed multifractal features in the blood pressure dynamics of CON as well as of DCM. At small scales, DFA and HFD of CON were significantly different from those of CON, reflecting patho-physiological changes. In conclusion, scaling analysis of blood pressure dynamics might lead to an enhanced assessment of autonomic cardiovascular control in patients with DCM.Mathias Baumert; Vico Baier; Andreas Vos

Postextrasystolic regulation patterns of blood pressure and heart rate in patients with idiopathic dilated cardiomyopathy

Assessment of fluctuations in heart rate (HR) following a premature ventricular complex (PVC) is valuable for identifying patients at high risk of sudden cardiac death. We hypothesised that postextrasystolic potentiation is the main determinant of the regulation patterns of blood pressure (BP) and HR following a PVC. Twelve patients with idiopathic dilated cardiomyopathy (IDC) and 13 control subjects with single PVCs (comparable coupling intervals) were investigated. Non-invasive finger arterial BP and ECGs were analysed. Regulation patterns following a single PVC were quantified using the indices postextrasystolic amplitude potentiation (PEAP) and maximum turbulence slope of five consecutive mean BP values (MBP-TS), and compared with the HR turbulence parameters turbulence slope (HR-TS) and turbulence onset (HR-TO). PEAP was significantly higher in IDC patients compared to controls (48.7 ± 32.6 vs. 9.8 ± 5.4 %, P < 0.01), whereas MBP-TS was lower (0.97 ± 0.60 vs. 2.07 ± 1.04 mmHg BBI−1 (BBI, beat-to-beat interval), P < 0.05), as was HR-TS (8.46 ± 7.90 vs. 30.73 ± 22.90 ms BBI−1, P < 0.01). HR-TO was significantly higher in IDC patients (−0.56 ± 2.19 vs. −5.52 ± 4.13 %, P < 0.01). In addition, the regulation patterns of BP and HR following a single PVC differed significantly between IDC patients and controls. Specifically, we observed pronounced PEAPs in IDC patients. The baroreflex response initiated by the low pressure amplitude of the PVC was suppressed in IDC patients due to the augmented potentiation of the first postextrasystolic blood pressure. Furthermore, IDC patients displayed impressive postextrasystolic pulsus alternans phenomena, whereas healthy subjects exhibited a typical baroreflex pattern. The pulsus alternans phenomenon seems to be triggered by a PVC

Rapid and Sensitive Multiplex Detection of <i>Burkholderia pseudomallei</i>-Specific Antibodies in Melioidosis Patients Based on a Protein Microarray Approach

<div><p>Background</p><p>The environmental bacterium <i>Burkholderia pseudomallei</i> causes the infectious disease melioidosis with a high case-fatality rate in tropical and subtropical regions. Direct pathogen detection can be difficult, and therefore an indirect serological test which might aid early diagnosis is desirable. However, current tests for antibodies against <i>B</i>. <i>pseudomallei</i>, including the reference indirect haemagglutination assay (IHA), lack sensitivity, specificity and standardization. Consequently, serological tests currently do not play a role in the diagnosis of melioidosis in endemic areas. Recently, a number of promising diagnostic antigens have been identified, but a standardized, easy-to-perform clinical laboratory test for sensitive multiplex detection of antibodies against <i>B</i>. <i>pseudomallei</i> is still lacking.</p><p>Methods and Principal Findings</p><p>In this study, we developed and validated a protein microarray which can be used in a standard 96-well format. Our array contains 20 recombinant and purified <i>B</i>. <i>pseudomallei</i> proteins, previously identified as serodiagnostic candidates in melioidosis. In total, we analyzed 196 sera and plasmas from melioidosis patients from northeast Thailand and 210 negative controls from melioidosis-endemic and non-endemic regions. Our protein array clearly discriminated between sera from melioidosis patients and controls with a specificity of 97%. Importantly, the array showed a higher sensitivity than did the IHA in melioidosis patients upon admission (cut-off IHA titer ≥1:160: IHA 57.3%, protein array: 86.7%; <i>p</i> = 0.0001). Testing of sera from single patients at 0, 12 and 52 weeks post-admission revealed that protein antigens induce either a short- or long-term antibody response.</p><p>Conclusions</p><p>Our protein array provides a standardized, rapid, easy-to-perform test for the detection of <i>B</i>. <i>pseudomallei</i>-specific antibody patterns. Thus, this system has the potential to improve the serodiagnosis of melioidosis in clinical settings. Moreover, our high-throughput assay might be useful for the detection of anti-<i>B</i>. <i>pseudomallei</i> antibodies in epidemiological studies. Further studies are needed to elucidate the clinical and diagnostic significance of the different antibody kinetics observed during melioidosis.</p></div

Characteristics of the <i>Burkholderia pseudomallei</i> antigens used in this study.

<p>Characteristics of the <i>Burkholderia pseudomallei</i> antigens used in this study.</p

Comparative calculation of IHA and protein array sensitivity.^#

<p>Comparative calculation of IHA and protein array sensitivity.<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004847#t003fn001" target="_blank">^#</a></p

Development of signal intensities of grouped antigens inducing a long-term antibody response (A) and a short-term antibody response (B).

<p>Sera of individual patients (n = 36) were drawn upon admission (week 0 <i>p</i>.<i>a</i>.), 12 and 52 weeks <i>p</i>.<i>a</i>. Two graphs per antigen are shown. Left: the mean signal intensity per serum. Right: number of sera recognizing the respective antigen. Figures include only data of antigens found to be significantly recognized by melioidosis-positive sera. Statistical analyses were performed using repeated-measures ANOVA followed by Bonferroni's Multiple Comparison test comparing signal intensities measured in sera of week 0, 12 and 52 <i>p</i>.<i>a</i>. (*<i>p</i><0.05; **<i>p</i><0.01; ***<i>p</i><0.001)</p