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.
Authors:Hagen Frickmann, N. Chantratita, Y. Gauthier, H. Neubauer, and R. Hagen
Discrimination of Burkholderia (B.) pseudomallei and B. mallei from environmental B. thailandensis is challenging. We describe a discrimination method based on sequence comparison of the ribosomal protein S21 (rpsU) gene.The rpsU gene was sequenced in ten B. pseudomallei, six B. mallei, one B. thailandensis reference strains, six isolates of B. pseudomallei, and 37 of B. thailandensis. Further rpsU sequences of six B. pseudomallei, three B. mallei, and one B. thailandensis were identified via NCBI GenBank. Three to four variable base-positions were identified within a 120-base-pair fragment, allowing discrimination of the B. pseudomallei/mallei-cluster from B. thailandensis, whose sequences clustered identically. All B. mallei and three B. pseudomallei sequences were identical, while 17/22 B. pseudomallei strains differed in one nucleotide (78A>C). Sequences of the rpsU fragment of ‘out-stander’ reference strains of B. cepacia, B. gladioli, B. plantarii, and B. vietnamensis clustered differently.Sequence comparison of the described rpsU gene fragment can be used as a supplementary diagnostic procedure for the discrimination of B. mallei/pseudomallei from B. thailandensis as well as from other species of the genus Burkholderia, keeping in mind that it does not allow for a differentiation between B. mallei and B. pseudomallei.
In spite of the developments in microbiological methods, blood cultures remain the cornerstone for the diagnosis of bacteraemia. Classically, minimum of two bottles are collected on a routine basis: an aerobic bottle, allowing preferential growth of aerobic and facultative anaerobic microorganisms, and an anaerobic bottle, providing suitable environment for strict anaerobic bacteria. Recent reports have documented a decrease in anaerobic bacteraemias and have questioned the need for routine anaerobic blood cultures. Bacteraemia due to anaerobic organisms occurs in 0.5–12% of blood cultures worldwide; however, recent studies from Europe and the USA presented inconsistent data regarding the prevalence of anaerobic bacteraemias between 1993 and 2006.The aims of this retrospective survey were to determine the prevalence of bacteraemias due to anaerobic bacteria and evaluate the importance of anaerobic blood cultures in a university hospital in Szeged, Hungary. We examined the occurrence of bacteraemias due to anaerobic bacteria during a 5-year period, from January 2005 to 2009, in order to identify current trends of anaerobic bacteraemias in our university.
Authors:A. Autengruber, M. Gereke, G. Hansen, C. Hennig, and Dunja Bruder
Immunological characterization of immune cells that reside in specific anatomic compartments often requires their isolation from the respective tissue on the basis of enzymatic tissue disintegration. Applying enzymatic digestion of primary splenocytes, we evaluated the impact of collagenase and dispase, two enzymes that are commonly used for the liberation of immune cells from tissues, on the detectability of 48 immunologically relevant surface molecules that are frequently used for flow cytometric identification, isolation, and characterization of immune cell subsets. Whereas collagenase treatment had only minor effects on surface expression of most molecules tested, dispase treatment considerably affected antibody-mediated detectability of the majority of surface markers in subsequent FACS analyses. This effect was long lasting and, in case of high-dose dispase treatment, evident for the majority of surface molecules even after 24 h of in vitro culture. Of note, high-dose dispase treatment not only affected surface expression of certain molecules but also impaired antigen-specific proliferation of CD4+ and CD8+ T cells. Together, our data indicate that enzymatic tissue disintegration can have profound effects on the expression of a variety of cell-surface molecules with direct consequences for phenotypic analysis, FACS- and MACS-based target cell isolation, and immune cell function in cell culture experiments.
Authors:É. Nemes-Nikodém, E. Vörös, K. Pónyai, L. Párducz, S. Kárpáti, F. Rozgonyi, and Eszter Ostorházi
From January 1, 2009 through December 31, 2011, from 33,753 blood samples for syphilis screening, Treponema pallidum infections were confirmed in 241 pregnant women at the Department of Dermatology, Venerology, and Dermatooncology of Semmelweis University Budapest. In this period, four children born to inadequately or untreated women were confirmed to have connatal syphilis. The height of rapid plasma reagin (RPR) titer was measured to determine the stage of the infection and to examine the success of the antilues therapy. The diagnosis of maternal syphilis infection was confirmed with enzyme linked immunosorbent assay (ELISA), T. pallidum particle agglutination (TPPA), and IgG and IgM immunoblots. Maternal IgM immunoblot results identify mothers at risk of delivering babies with connatal syphilis better than the height of maternal RPR titer. The standard serological tests are less useful in newborns because of IgG transfer across the placenta. IgM test which depends on the infant’s response has more specificity in diagnosing connatal syphilis.
Monocytes are important cell types of the innate immune system. Recent scientific evidence suggests that monocytes not only play a crucial role in our innate immune system by defending the host from intruding microbial pathogens but they also contribute to the pathogenesis and progression of diseases such as liver fibrosis, atherosclerosis, multiple sclerosis, and tumor metastasis. In addition, monocytes and monocyte-derived macrophages play a crucial beneficial role in the liver fibrosis regression, muscle regeneration, and the clearance of the β-amyloid plaques in Alzheimer’s disease. Here, we summarize the origin, plasticity, and pathogenic potential of monocytes and monocyte-derived macrophages, as well as their positive role in the regression of some common diseases. Elucidating the comprehensive immunological role of monocytes will provide therapeutic advantages in either controlling disease progression or favoring the regression of the disease state.
Authors:Yoshiaki Kumamoto, T. Matsumoto, M. Fujisawa, and S. Arakawa
This prospective, multicenter clinical trial was conducted to compare the performance of the cobas® 4800 CT/NG, APTIMA Combo 2®, and ProbeTec™ ET CT/GC assays for the detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in Japan. From 1274 male and female patients, more than 1900 urine, endocervical and throat specimens were collected. Positive and negative concordance rates for CT and NG results obtained for urine and endocervical samples collected from the same patient were high in all three assays (range 96.0–99.6%). The accuracy of the cobas® 4800 CT/NG test did not differ significantly from that of the APTIMA Combo 2® and ProbeTec™ ET CT/GC assays. The accuracy of the assays did not change depending on the order of collection of endocervical specimens. Concordance rates for results obtained for throat swabs and mouthwashes in the ProbeTec™ ET CT/GC and cobas® 4800 CT/NG assays, respectively, were 98.8% for CT and 95.1% for NG. These data suggest that the cobas®4800 CT/NG test is a reliable and highly accurate diagnostic tool for the detection of CT and NG in urine, genital, and oral specimens. Owing to the high correlation of urine and endocervical swab results and the ease of acquisition, urine samples are suggested as the specimen of choice for screening of CT and NG.