Methicillin-resistant Staphylococcus aureus from infections in horses in Germany are frequent colonizers of veterinarians but rare among MRSA from infections in humans

AbstractA total of 272 methicillin-resistant Staphylococcus aureus (MRSA) from equine infections originating from 17 equine hospitals and 39 veterinary practices in Germany as well as 67 isolates from personnel working at equine clinics were subjected to molecular typing. The majority of isolates from horses was attributed to clonal complex (CC) 398 (82.7%). Within CC398, 66% of isolates belonged to a subpopulation (clade) of CC398, which is associated with equine clinics.MRSA attributed to CC8 (ST254, t009, t036, SCCmecIV; ST8, t064, SCCmecIV) were less frequent (16.5%). Single isolates were attributed to ST1, CC22, ST130, and ST1660. The emergence of MRSA CC22 and ST130 in horses was not reported so far. Nasal MRSA colonization was found in 19.5% of veterinary personnel with occupational exposure to horses. The typing characteristics of these isolates corresponded to isolates from equine infections.Comparing typing characteristics of equine isolates with those of a substantial number of isolates from human infections typed at the German Reference Center for Staphylococci and Enterococci (2006–2014; n=10864) yielded that the proportion of isolates exhibiting characteristics of MRSA from equine medicine is very low (<0.5%). As this low proportion was also found among MRSA originating from nasal screenings of human carriers not suffering from a staphylococcal infection (n=5546) transmission of MRSA from equine clinics to the community seems to be rare so far

Antibiotic resistance and molecular epidemiology of Staphylococcus aureus in Nigeria

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus aureus </it>is an important pathogen causing a wide range of infections in the hospital and community setting. In order to have adequate information for treatment of <it>S. aureus </it>infections, it is crucial to understand the trends in the antibiotic-resistance patterns. In addition, the occurrence and changes in types of <it>S. aureus</it>, clonal identities, and their geographic spread is essential for the establishment of adequate infection control programmes. In this study, 68 <it>S. aureus </it>isolates obtained from clinical and non-clinical sources in Nigeria between January and April 2009 were characterized using phenotypic and molecular methods.</p> <p>Results</p> <p>All the <it>S. aureus </it>isolates were susceptible to teicoplanin, vancomycin, phosphomycin, fusidic acid, rifampicin, daptomycin, mupirocin, linezolid and tigecycline. Sixteen percent of the isolates were resistant to oxacillin, while 55% and 72% of isolates were resistant to tetracycline and trimethoprim/sulphamethoxazole (cotrimoxazole), respectively (Table <tblr tid="T1">1</tblr>). There was excellent correlation between the broth microdilution assay and detection of antibiotic resistance genes by the multiplex PCR, in the determination of <it>S. aureus </it>resistance to erythromycin, gentamicin, methicillin and tetracycline. A total of 28 <it>spa </it>types were identified in the study, and the predominant <it>spa </it>type among the methicillin-susceptible <it>S. aureus </it>(MSSA) isolates was t084 (13 isolates). The t037-ST241-SCC<it>mec</it>III type was the only clone identified in Maiduguri (North-East Nigeria) while in South-West Nigeria, diversity among the MRSA isolates (t451-ST8-SCC<it>mec</it>V; t008-ST94-SCC<it>mec</it>IV; t002-ST5-SCC<it>mec</it>V; t064-ST8-SCC<it>mec</it>V) was observed. The toxin genes <it>seh </it>and <it>etd </it>were detected in isolates affiliated with clonal complexes CC1, CC80 and sequence type ST25, respectively. The proportion of PVL-positive isolates among MSSA was high (40%). Most of the PVL-positive MSSA isolates were obtained from wound infections and associated with clonal complexes CC1, CC30, CC121 and with sequence type ST152.</p> <tbl id="T1"> <title> <p>Table 1</p> </title> <caption> <p>Antibiotic resistance profile of <it>S. aureu</it><it>s </it>(MSSA and MRSA) from Nigeria</p> </caption> <tblbdy cols="4"> <r> <c> <p/> </c> <c cspan="3" ca="left"> <p><b>Number (%) of resistant isolates among</b>:</p> </c> </r> <r> <c ca="left"> <p><b>Antibiotic</b></p> </c> <c ca="left"> <p><b>MSSA</b></p> <p><b>(n = 57)</b></p> </c> <c ca="left"> <p><b>MRSA</b></p> <p><b>(n = 11)</b></p> </c> <c ca="left"> <p><b>Total</b></p> <p><b>(n = 68)</b></p> </c> </r> <r> <c cspan="4"> <hr/> </c> </r> <r> <c ca="left"> <p>Penicillin</p> </c> <c ca="left"> <p>49 (86)</p> </c> <c ca="left"> <p>11 (100)</p> </c> <c ca="left"> <p>60 (88.2)</p> </c> </r> <r> <c ca="left"> <p>Oxacillin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>11 (100)</p> </c> <c ca="left"> <p>11 (16.2)</p> </c> </r> <r> <c ca="left"> <p>Teicoplanin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Vancomycin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Gentamicin</p> </c> <c ca="left"> <p>1 (1.8)</p> </c> <c ca="left"> <p>9 (81.8)</p> </c> <c ca="left"> <p>10 (14.7)</p> </c> </r> <r> <c ca="left"> <p>Tetracycline</p> </c> <c ca="left"> <p>27 (47.4)</p> </c> <c ca="left"> <p>11 (100)</p> </c> <c ca="left"> <p>38 (55.9)</p> </c> </r> <r> <c ca="left"> <p>Ciprofloxacin</p> </c> <c ca="left"> <p>12 (21.1)</p> </c> <c ca="left"> <p>8 (72.7)</p> </c> <c ca="left"> <p>20 (29.4)</p> </c> </r> <r> <c ca="left"> <p>Moxifloxacin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>7 (63.6)</p> </c> <c ca="left"> <p>7 (10.3)</p> </c> </r> <r> <c ca="left"> <p>Trimethoprim/sulfamethoxazole</p> </c> <c ca="left"> <p>39 (68.4)</p> </c> <c ca="left"> <p>10 (90.9)</p> </c> <c ca="left"> <p>49 (72.1)</p> </c> </r> <r> <c ca="left"> <p>Phosphomycin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Fusidic acid</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Erythromycin</p> </c> <c ca="left"> <p>2 (3.5)</p> </c> <c ca="left"> <p>6 (54.5)</p> </c> <c ca="left"> <p>8 (11.8)</p> </c> </r> <r> <c ca="left"> <p>Clindamycin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>6 (54.5)</p> </c> <c ca="left"> <p>6 (8.8)</p> </c> </r> <r> <c ca="left"> <p>Rifampicin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Daptomycin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Mupirocin</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Linezolid</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> <r> <c ca="left"> <p>Tigecycline</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> <c ca="left"> <p>0 (0)</p> </c> </r> </tblbdy> </tbl> <p>Conclusions</p> <p>The use of phenotypic and molecular methods provided useful information on antibiotic resistance and molecular diversity of <it>S. aureus </it>in Nigeria. The high proportion of PVL-positive MSSA isolates affiliated to various clonal complexes and detected in all the health institutions is a major concern, both as a source of severe infections and as a potential reservoir that could lead to the emergence of PVL-positive MRSA. This study presents the first baseline information on the nature of the antibiotic resistance genes from <it>S. aureus </it>isolates in Nigeria. There is the need to curtail the spread and establishment of MRSA and PVL-positive MSSA clones in Nigerian health care institutions.</p

Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

We present phonon dispersions, element-resolved vibrational density of states (VDOS) and corresponding thermodynamic properties obtained by a combination of density functional theory (DFT) and nuclear resonant inelastic X-ray scattering (NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and thin epitaxial films. We see distinct differences in the VDOS of the antiferromagnetic (AF) and ferromagnetic (FM) phase which provide a microscopic proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular sensitivity to the slight tetragonal distortions present in epitaxial films, which is not encountered in the AF phase. This results in a notable change in lattice entropy, which is important for the comparison between thin film and bulk results. Our calculations confirm the recently reported lattice instability in the AF phase. The imaginary frequencies at the $X$-point depend critically on the Fe magnetic moment and atomic volume. Analyzing these non vibrational modes leads to the discovery of a stable monoclinic ground state structure which is robustly predicted from DFT but not verified in our thin film experiments. Specific heat, entropy and free energy calculated within the quasiharmonic approximation suggest that the new phase is possibly suppressed because of its relatively smaller lattice entropy. In the bulk phase, lattice degrees of freedom contribute with the same sign and in similar magnitude to the isostructural AF-FM phase transition as the electronic and magnetic subsystems and therefore needs to be included in thermodynamic modeling.Comment: 15 pages, 12 figure

Preliminary Test of the Reduction Capacity for the Intestinal Adsorption of Skatole and Indole in Weaning Piglets by Pure and Coated Charcoal

To reduce the risk of boar taint, intact male piglets are immuno‐ or surgically castrated. One alternative is reducing skatole by adding skatole reducing or adsorbing substances to the boars’ diet. Charcoal with a high capacity for adsorbing skatole and indole in vitro (tested before, data not shown) was fed to the boars to test the hypothesis that a fat coating prevents the unspecific adsorption of charcoal before entry into the large intestine while increasing skatole adsorption. Twelve male and six female weaning piglets with initial body weights of 7.74 ± 0.75 kg were fed for 18 (or 19) days with either 2% pure (untreated) charcoal or 4% coated (50% charcoal + 50% fat‐coating) charcoal or no charcoal. After euthanasia, skatole and indole were quantified in caecum and colon chyme. Skatole and indole contents in caecum chyme were significantly lower (p < 0.05) in the group fed with coated charcoal (33 ± 4.2, 7 ± 2.8 μg/gDM, respectively) than in the group fed with pure charcoal (51 ± 7.3, 14 ± 3.0 μg/gDM) or with no charcoal (73 ± 12.6, 15 ± 1.7 μg/gDM). Similar effects were obvious for colon chyme. The results indicate that a fat coating of charcoal might prevent unspecific adsorption in the small intestine and might consequently lead to a higher adsorption capacity for skatole and indole in the large intestine, as skatole and indole concentrations in the chyme of caecum and colon were approximately 50% lower in the piglets who received coated charcoal

Small Extracellular Vesicles from Peripheral Blood of Aged Mice Pass the Blood-Brain Barrier and Induce Glial Cell Activation

Extracellular vesicles (EVs), including small EVs (sEVs), are involved in neuroinflammation and neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Yet, increased neuroinflammation can also be detected in the aging brain, and it is associated with increased glial activation. Changes in EV concentration are reported in aging tissues and senescence cells, suggesting a role of EVs in the process of aging. Here, we investigated the effect of peripheral sEVs from aged animals on neuroinflammation, specifically on glial activation. sEVs were isolated from the peripheral blood of young (3 months) and aged (24 months) C57BL/6J wildtype mice and injected into the peripheral blood from young animals via vein tail injections. The localization of EVs and the expression of selected genes involved in glial cell activation, including Gfap , Tgf- β , Cd68 , and Iba1 , were assessed in brain tissue 30 min, 4 h, and 24 h after injection. We found that sEVs from peripheral blood of aged mice but not from young mice altered gene expression in the brains of young animals. In particular, the expression of the specific astrocyte marker, Gfap , was significantly increased, indicating a strong response of this glial cell type. Our study shows that sEVs from aged mice can pass the blood-brain barrier (BBB) and induce glial cell activation

Single-Nucleotide Polymorphism Genotyping Identifies a Locally Endemic Clone of Methicillin-Resistant Staphylococcus aureus

We developed, tested, and applied a TaqMan real-time PCR assay for interrogation of three single-nucleotide polymorphisms that differentiate a clade (termed ‘t003-X’) within the radiation of methicillin-resistant Staphylococcus aureus (MRSA) ST225. The TaqMan assay achieved 98% typeability and results were fully concordant with DNA sequencing. By applying this assay to 305 ST225 isolates from an international collection, we demonstrate that clade t003-X is endemic in a single acute-care hospital in Germany at least since 2006, where it has caused a substantial proportion of infections. The strain was also detected in another hospital located 16 kilometers away. Strikingly, however, clade t003-X was not found in 62 other hospitals throughout Germany nor among isolates from other countries, and, hence, displayed a very restricted geographical distribution. Consequently, our results show that SNP-typing may be useful to identify and track MRSA clones that are specific to individual healthcare institutions. In contrast, the spatial dissemination pattern observed here had not been resolved by other typing procedures, including multilocus sequence typing (MLST), spa typing, DNA macrorestriction, and multilocus variable-number tandem repeat analysis (MLVA)

Nasal Colonization of Humans with Methicillin-Resistant Staphylococcus aureus (MRSA) CC398 with and without Exposure to Pigs

Background: Studies in several European countries and in North America revealed a frequent nasal colonization of livestock with MRSA CC398 and also in humans with direct professional exposure to colonized animals. The study presented here addresses the question of further transmission to non exposed humans. Methods: After selecting 47 farms with colonized pigs in different regions of Germany we sampled the nares of 113 humans working daily with pigs and of their 116 non exposed family members. The same was performed in 18 veterinarians attending pig farms and in 44 of their non exposed family members. For investigating transmission beyond families we samples the nares of 462 pupils attending a secondary school in a high density pig farming area. MRSA were detected by direct culture on selective agar. The isolates were typed by means of spa-sequence typing and classification of SCCmec elements. For attribution of spa sequence types to clonal lineages as defined by multi locus sequence typing we used the BURP algorithm. Antibiotic susceptibility testing was performed by microbroth dilution assay. Results: At the farms investigated 86% of humans exposed and only 4.3% of their family members were found to carry MRSA exhibiting spa-types corresponding to clonal complex CC398. Nasal colonization was also found in 45% of veterinarians caring for pig farms and in 9% of their non exposed family members. Multivariate analysis revealed that antibiotic usage prior to sampling beard no risk with respect to colonization. From 462 pupils only 3 were found colonized, all 3 were living on pig farms. Conclusion: These results indicate that so far the dissemination of MRSA CC398 to non exposed humans is infrequent and probably does not reach beyond familial communities

Polymorphisms in the Mitochondrial Genome Are Associated With Bullous Pemphigoid in Germans

Bullous pemphigoid (BP) is the most prevalent autoimmune skin blistering disease and is characterized by the generation of autoantibodies against the hemidesmosomal proteins BP180 (type XVII collagen) and BP230. Most intriguingly, BP is distinct from other autoimmune diseases because it predominantly affects elderly individuals above the age of 75 years, raising the question why autoantibodies and the clinical lesions of BP emerges mostly in this later stage of life, even in individuals harboring known putative BP-associated germline gene variants. The mitochondrial genome (mtDNA) is a potential candidate to provide additional insights into the BP etiology; however, the mtDNA has not been extensively explored to date. Therefore, we sequenced the whole mtDNA of German BP patients (n = 180) and age- and sex-matched healthy controls (n = 188) using next generation sequencing (NGS) technology, followed by the replication study using Sanger sequencing of an additional independent BP (n = 89) and control cohort (n = 104). While the BP and control groups showed comparable mitochondrial haplogroup distributions, the haplogroup T exhibited a tendency of higher frequency in BP patients suffering from neurodegenerative diseases (ND) compared to BP patients without ND (50%; 3 in 6 BP with haplogroup T). A total of four single nucleotide polymorphisms (SNPs) in the mtDNA, namely, m.16263T>C, m.16051A>G, and m.16162A>G in the D-loop region of the mtDNA, and m.11914G>A in the mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4 gene (MT-ND4), were found to be significantly associated with BP based on the meta-analysis of our NGS data and the Sanger sequencing data (p = 0.0017, p = 0.0129, p = 0.0076, and p = 0.0132, respectively, Peto's test). More specifically, the three SNPs in the D-loop region were negatively, and the SNP in the MT-ND4 gene was positively associated with BP. Our study is the first to interrogate the whole mtDNA in BP patients and controls and to implicate multiple novel mtDNA variants in disease susceptibility. Studies using larger cohorts and more diverse populations are warranted to explore the functional consequences of the mtDNA variants identified in this study on immune and skin cells to understand their contributions to BP pathology

Fetal autonomic brain age scores, segmented heart rate variability analysis, and traditional short term variability

Disturbances of fetal autonomic brain development can be evaluated from fetal heart rate patterns (HRP) reflecting the activity of the autonomic nervous system. Although HRP analysis from cardiotocographic (CTG) recordings is established for fetal surveillance, temporal resolution is low. Fetal magnetocardiography (MCG), however, provides stable continuous recordings at a higher temporal resolution combined with a more precise heart rate variability (HRV) analysis. A direct comparison of CTG and MCG based HRV analysis is pending. The aims of the present study are: (i) to compare the fetal maturation age predicting value of the MCG based fetal Autonomic Brain Age Score (fABAS) approach with that of CTG based Dawes-Redman methodology; and (ii) to elaborate fABAS methodology by segmentation according to fetal behavioral states and HRP. We investigated MCG recordings from 418 normal fetuses, aged between 21 and 40 weeks of gestation. In linear regression models we obtained an age predicting value of CTG compatible short term variability (STV) of R2 = 0.200 (coefficient of determination) in contrast to MCG/fABAS related multivariate models with R2 = 0.648 in 30 min recordings, R2 = 0.610 in active sleep segments of 10 min, and R2 = 0.626 in quiet sleep segments of 10 min. Additionally segmented analysis under particular exclusion of accelerations (AC) and decelerations (DC) in quiet sleep resulted in a novel multivariate model with R2 = 0.706. According to our results, fMCG based fABAS may provide a promising tool for the estimation of fetal autonomic brain age. Beside other traditional and novel HRV indices as possible indicators of developmental disturbances, the establishment of a fABAS score normogram may represent a specific reference. The present results are intended to contribute to further exploration and validation using independent data sets and multicenter research structures

Polymorphisms in the Mitochondrial Genome Are Associated With Bullous Pemphigoid in Germans

Bullous pemphigoid (BP) is the most prevalent autoimmune skin blistering disease and is characterized by the generation of autoantibodies against the hemidesmosomal proteins BP180 (type XVII collagen) and BP230. Most intriguingly, BP is distinct from other autoimmune diseases because it predominantly affects elderly individuals above the age of 75 years, raising the question why autoantibodies and the clinical lesions of BP emerges mostly in this later stage of life, even in individuals harboring known putative BP-associated germline gene variants. The mitochondrial genome (mtDNA) is a potential candidate to provide additional insights into the BP etiology; however, the mtDNA has not been extensively explored to date. Therefore, we sequenced the whole mtDNA of German BP patients (n = 180) and age- and sex-matched healthy controls (n = 188) using next generation sequencing (NGS) technology, followed by the replication study using Sanger sequencing of an additional independent BP (n = 89) and control cohort (n = 104). While the BP and control groups showed comparable mitochondrial haplogroup distributions, the haplogroup T exhibited a tendency of higher frequency in BP patients suffering from neurodegenerative diseases (ND) compared to BP patients without ND (50%; 3 in 6 BP with haplogroup T). A total of four single nucleotide polymorphisms (SNPs) in the mtDNA, namely, m.16263T>C, m.16051A>G, and m.16162A>G in the D-loop region of the mtDNA, and m.11914G>A in the mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4 gene (MT-ND4), were found to be significantly associated with BP based on the meta-analysis of our NGS data and the Sanger sequencing data (p = 0.0017, p = 0.0129, p = 0.0076, and p = 0.0132, respectively, Peto's test). More specifically, the three SNPs in the D-loop region were negatively, and the SNP in the MT-ND4 gene was positively associated with BP. Our study is the first to interrogate the whole mtDNA in BP patients and controls and to implicate multiple novel mtDNA variants in disease susceptibility. Studies using larger cohorts and more diverse populations are warranted to explore the functional consequences of the mtDNA variants identified in this study on immune and skin cells to understand their contributions to BP pathology