Authors:Sai Duraisingham, Steven Hanson, Matthew Buckland, Sofia Grigoriadou, and Hilary Longhurst
Pseudomonas aeruginosa (PA) is commonly isolated from the respiratory secretions of antibody deficiency patients, but the significance of this has not been well studied. We have reviewed our adult antibody deficiency cohort of 179 patients and assessed the prevalence and characteristics of PA infection and the effects of early antibiotic eradication treatments. Of the 34 patients with PA, 55.9% (19) underwent successful eradication and were infection-free, 38.2% (13) had intermittent infection, and 5.9% (2) had chronic PA. PA infection was significantly associated with bronchiectasis (p < 0.0001), with 36.1% (22 out of 61) of patients with bronchiectasis developing a PA infection. Infection status was also significantly associated with chronic sinusitis (p < 0.0001). Most treated PA exacerbations were symptomatic and with colony counts of ≥1000 cfu/ml. Current eradication protocols used at our center involve early treatment at first positive isolate with ciprofloxacin for 3 weeks and nebulized colomycin for 3 months, and if eradication fails, intravenous ceftazidime and gentamycin or colomycin is administered for 2 weeks. Continued sputum surveillance and early eradication treatments upon positive PA culture may help to limit chronic PA infection in antibody deficiency patients.
Authors:Sebastian Schmidt, Markus Heimesaat, André Fischer, Stefan Bereswill, and Matthias Melzig
The resistance of commensal bacteria to first and second line antibiotics has reached an alarming level in many parts of the world and endangers the effective treatment of infectious diseases. In this study, the influence of the plant-derived natural saponins glycyrrhizic acid, β-aescin, α-hederin, hederacoside C, and primulic acid 1 on the susceptibility of vancomycin-resistant enterococci (VRE) against antibiotics of clinical relevance was investigated in 20 clinical isolates. Furthermore, the antibacterial properties of saponins under study against VRE were determined in vitro. Results reveal that the susceptibility of VRE against gentamicin, teicoplanin, and daptomycin was enhanced in the presence of the saponin glycyrrhizic acid. Most importantly, glycyrrhizic acid (1 mg/ml) diminished the minimal inhibitory concentration (MIC) of gentamicin in gentamicin low-level intrinsic resistant VRE from 2 − >8 mg/l to ≤ 0.125−1 mg/l. The adding of β-aescin, α-hederin, hederacoside C, and primulic acid 1 to the antibiotics under study showed, compared to glycyrrhizic acid, less influence on the antibiotic potency. Only glycyrrhizic acid (1 mg/ml) and α-hederin (0.2 mg/ml) showed weak antibacterial properties against the clinical isolates. Our study points towards a therapeutic potential of saponins in the coapplication with antibiotics for bacterial infections.
Authors:M. Alutis, U. Grundmann, A. Fischer, A. Kühl, S. Bereswill, and M. Heimesaat
Increased levels of the matrix metalloproteinases-2 and -9 (also referred to gelatinase-A and -B, respectively) can be detected in intestinal inflammation. We have recently shown that selective gelatinase blockage by the synthetic compound RO28-2653 ameliorates acute murine ileitis and colitis. We here investigated whether RO28-2653 exerts anti-inflammatory effects in acute Campylobacter jejuni-induced enterocolitis of gnotobiotic IL-10−/− mice generated following antibiotic treatment. Mice were perorally infected with C. jejuni (day 0) and either treated with RO28-2653 (75 mg/kg body weight/day) or placebo from day 1 until day 6 post infection (p.i.) by gavage. Irrespective of the treatment, infected mice displayed comparable pathogen loads within the gastrointestinal tract. Following RO28-2653 administration, however, infected mice exhibited less severe symptoms such as bloody diarrhea as compared to placebo controls. Furthermore, less distinct apoptosis but higher numbers of proliferating cells could be detected in the colon of RO28-2653-treated as compared to placebo-treated mice at day 7 p.i. Remarkably, gelatinase blockage resulted in lower numbers of T- and B-lymphocytes as well as macrophages and monocytes in the colonic mucosa of C. jejuni-infected gnotobiotic IL-10−/− mice. Taken together, synthetic gelatinase inhibition exerts anti-inflammatory effects in experimental campylobacteriosis.
Authors:D. Wester, S. Rideout-Hanzak, C. Britton, and H. Whitlaw
Severe wildfires are increasing in extent in the western US. We used a matched-pairs design with plots in burned and non-burned areas to study effects of the East Amarillo Complex (EAC) wildfires on mixed grass prairie mean community composition and variability in composition. Species composition and ground cover data were collected at 5 study sites each year for three years following the EAC. Fire effects on mean species composition were analyzed with permutational analyses of variance; temporal patterns were analyzed with permutational anova and nonmetric multidimensional scaling; and an index of multivariate dispersion was used to assess variability in plant community composition. We found weak immediate impacts (year 1) of wildfire on mean species composition, but strong impacts by year three. Two general patterns of changes in mean species composition emerged: at 3 study sites, there was a progressive divergence in similarity between burned and non-burned areas following wildfire whereas at 2 study sites, wildfire effects lessened over time. In contrast, a trend of increased homogeneity in burned vegetation relative to non-burned vegetation was apparent at all 5 study sites 2 to 3 years post-fire; burned areas also had higher species diversity, higher evenness but similar species richness 3 years post-fire. Ground cover composition, which was immediately impacted by wildfire through removal of residual dry matter, was fully recovered to non-burned conditions 3 years after wildfire. We observed little seedling recruitment either of native or exotic species following wildfire. Community composition changes in burned areas were likely the result of changing dominance relationships among plants that survived the wildfires rather than the result of recruitment of new individuals in gaps created by dead plants. Given the growth form of perennial C4 grasses and the fact that these grasslands evolved in the context of repeated fire, it is likely that changes in mean species composition and compositional variability are short-term responses.
Notothylas irregularis Chantanaorr. is described and illustrated from Doi Chiang Dao Wildlife Sanctuary, Chiang Dao District, Chiang Mai Province, northern Thailand. It is similar to Notothylas yunnanensis T. Peng et R. L. Zhu, but differs in its capsules with a line of incrassate cells.
Different long-term experiments were carried on chernozem (Debrecen) and loamy (Hajdúböszörmény) soils. They included the most important agrotechnical, biological (hybrid) and agroecological (crop year, soil) factors in maize production. This paper evaluated the results of polyfactorial long-term experiments. For the maize the most favourable crop rotation was winter wheat (in a tri-culture) with an N 60–120, P2O5 60–70, K2O and 90–110 kg ha−1, and a density of 75–90,000 plants ha−1. The different input levels of maize crop management systems can modify an adaptive capacity to ecological conditions and the resilience of agro-ecosystems. The optimalization of agrotechnical elements reduces the harmful climatic effects. The yields of maize varied between 2–11 t ha−1 in extensive and 10–15 t ha−1 in intensive crop management systems, respectively.
Multivariate analysis of variance, based on randomization (permutation) test, has become an important tool for ecological data analyses. However, a comprehensive evaluation of the accuracy and power of available methods is still lacking. This is a thorough examination of randomization tests for multivariate group mean differences. With simulated data, the accuracy and power of randomization tests were evaluated using different test statistics in one-factor multivariate analysis of variance (MANOVA). The evaluations span a wide spectrum of data types, including specified and unspecified (field data) distributional properties, correlation structures, homogeneous to very heterogeneous variances, and balanced an unbalanced group sizes. The choice of test statistic strongly affected the results. Sums of squares between groups (Qb) computed on Euclidean distances (Qb-EUD) gave better accuracy. Qb on Bray-Curtis, Manhattan or Chord distances, the multiresponse permutation procedure (MRPP) and the sum of univariate ANOVA F produced severely inflated type I errors under increasing variance heterogeneity among groups, a common scenario in ecological data. Despite pervasive claims in the ecological literature, the evidence thus suggests caution when using test statistics other than Qb-EUD.
Authors:Prabhu Nesargikar, B. Spiller, and R. Chavez
Since its discovery in the 19th century, the complement system has developed into a clinically significant entity. The complement system has been implicated in a variety of clinical conditions, from autoimmune diseases to ischemia-reperfusion injury in transplantation. This article charts the historical progress of our understanding of the complement system and provides a synopsis on the activation pathways and its inherent regulators.
Authors:Hagen Frickmann, P. Gawlik, S. Crusius, and A. Podbielski
The objective of this paper was to investigate whether retrospective pulsed-field gel electrophoresis (PFGE) of methicillin-resistant Staphylococcus aureus (MRSA) isolates at two-year intervals is suitable and sufficient to demonstrate changes in the clonal composition of MRSA isolates and to identify previously undetected local outbreaks. PFGE patterns of 400 MRSA isolates were collected between 2004 and 2008 at the University of Rostock Hospital in Germany, and were used to assess the prevalence of MRSA clones at different time points. Only minor changes were detected. The combined analysis of all isolates that were collected per year reduced the time needed to perform this laborious procedure. The retrospective identification of outbreaks may require shorter intervals. Improved infection prevention and control measures prevented further outbreaks in previously affected hospital departments. In conclusion, PGFE at two-year intervals is sufficient to detect changes in the clonal composition of local MRSA isolates. If time for identification is important during outbreak investigations, more rapid methods with a similarly high discriminatory power such as spa typing should be used.
Authors:Katrin Gentil, A. Hoerauf, and E. Pearlman
Immune responses to filarial parasites like the river blindness inducing Onchocerca volvulus are obscured by combined reactions to the filarial nematodes themselves and their endosymbiont bacteria Wolbachia. Overall, infection with filarial nematodes induces a strong Th2 response characterized by IL-5 production and to a lesser degree a Th1 response and IFNγ production. Neutrophil and eosinophil infiltration into the corneal stroma are hallmark features of Onchocerca volvulus stimulation in a mouse model of river blindness. To determine the splenic and corneal response to filarial antigens in the absence of Wolbachia, C57BL/6 mice were immunized subcutaneously with either endosymbiotic Wolbachia alone, a soluble extract from the filaria Acanthocheilonema viteae that does not contain Wolbachia, or both, and injected into the corneal stroma. Neutrophil and eosinophil infiltration into the cornea was assessed by immunohistochemistry. In addition, Th1- and Th2-associated responses to filaria or Wolbachia were investigated by determining IL-5 and IFN-γ production by splenocytes. We found that A. viteae in the absence of Wolbachia induced IL-5 production and eosinophil infiltration, but not IFN-γ. Conversely, Wolbachia induced IFN-γ production and no migration of eosinophils. There was no difference in neutrophil infiltration. Together, these findings demonstrate a distinct Th-associated phenotype induced by filaria and Wolbachia.