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Antiparasitic treatment suppresses production and avidity of Toxoplasma gondii-specific antibodies in a murine model of acute infection
Authors: C. Alvarado-Esquivel, A. Niewiadomski, B. Schweickert and O. Liesenfeld

Abstract

Infection with Toxoplasma gondii during pregnancy may result in congenital transmission of the parasite. Infection is commonly diagnosed using serological tests for IgG, IgM and IgA antibodies. Avidity of IgG antibodies is used to exclude acute infection. Few studies have investigated the impact of antiparasitic treatment on the production of anti-T. gondii antibody and the avidity of IgG antibodies. We therefore investigated the production of IgG, IgM, and IgA antibodies and IgG avidity in a murine model of acute infection with 10 cysts of T. gondii. All antibody classes increased following infection. Treatment of mice with py rime thamine/ sulfadiazine but not with spiramycin or azithromycin at dosages equivalent to those used in patients resulted in a significant decrease in the concentration of T. gondii-specific IgG and IgM antibodies postinfection. IgG and IgM antibody decreases were paralleled by a significant reduction in cyst numbers in brains of mice treated with pyrimethamine/sulfadiazine but not with other drugs. In contrast, treatment with atovaquone did significantly reduce the concentrations of IgM antibodies and resulted in reduced IgG avidity indices. T. gondii-specific DNA was not detected in blood between days 1 and 3. In conclusion, antiparasitic treatment with pyrimethamine/sulfadiazine and atovaquone appears to impact the generation of antibody responses against T. gondii. Future studies will have to determine the specific impact of antiparasitic treatment on antibody responses and the consequences for the management of patients infected with T. gondii.

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Performance of the cobas® influenza A/B assay for rapid PCR-based detection of influenza compared to Prodesse ProFlu+ and viral culture
Authors: L. Chen, Y. Tian, S. Chen and O. Liesenfeld

Rapid and accurate diagnosis of influenza is important for patient management and infection control. We determined the performance of the cobas® Influenza A/B assay, a rapid automated nucleic acid assay performed on the cobas® Liat System for qualitative detection of influenza A and influenza B from nasopharyngeal (NP) swab specimens. Retrospective frozen and prospectively collected NP swabs from patients with signs and symptoms of influenza collected in universal transport medium (UTM) were tested at multiple sites including CLIA-waived sites using the cobas® Influenza A/B assay. Results were compared to the Prodesse ProFlu+ assay and to viral culture. Compared to the Prodesse ProFlu+ Assay, sensitivities of the cobas® Influenza A/B assay for influenza A and B were 97.7 and 98.6%, respectively; specificity was 99.2 and 99.4%. Compared to viral culture, the cobas® Influenza A/B assay showed sensitivities of 97.5 and 96.9% for influenza virus A and B, respectively; specificities were 97.9% for both viruses. Polymerase chain reaction (PCR)/sequencing showed that the majority of viral culture negative but cobas® Influenza A/B positive results were true positive results, indicating that the cobas® Influenza A/B assay has higher sensitivity compared to viral culture.

In conclusion, the excellent accuracy, rapid time to result, and remarkable ease of use make the cobas® Influenza A/B nucleic acid assay for use on the cobas® Liat System a highly suitable point-of-care solution for the management of patients with suspected influenza A and B infection.

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Molecular diagnosis of sepsis: New aspects and recent developments
Authors: O. Liesenfeld M.D., L. Lehman, K.-P. Hunfeld and G. Kost

Abstract

By shortening the time to pathogen identification and allowing for detection of organisms missed by blood culture, new molecular methods may provide clinical benefits for the management of patients with sepsis. While a number of reviews on the diagnosis of sepsis have recently been published we here present up-to-date new developments including multiplex PCR, mass spectrometry and array techniques. We focus on those techniques that are commercially available and for which clinical studies have been performed and published.

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Tim-3 is differently expressed in genetically susceptible C57BL/6 and resistant BALB/c mice during oral infection with Toxoplasma gondii
Authors: L. C. Berrocal Almanza, M. Muñoz, A. A. Kühl, T. Kamradt, M. M. Heimesaat and O. Liesenfeld

Abstract

Tim-3 has opposing roles in innate and adaptive immunities. It not only dampens CD4+ and CD8+ T cells responses but also enhances the ability of macrophages to eliminate intracellular pathogens. After peroral infection with 100 cysts of Toxoplasma gondii genetically susceptible C57BL/6 mice develop an unchecked Th1 response associated with the development of small intestinal immunopathology. Here we report that upon infection with T. gondii, both susceptible C57BL/6 and resistant BALB/c mice exhibit increased frequencies of Tim-3+ cells in spleens and mesenteric lymph nodes. The number of Tim-3+ cells was significantly higher in C57BL/6 than in BALB/c mice. Tim-3 was expressed by macrophages, dendritic, natural killer, as well as CD4+ and CD8+ T cells. Highest frequencies of Tim-3+ cells were observed at the peak of Th1 responses (day 7 post infection) concurrent with the development of ileal immunopathology. Infected Tim-3-deficient BALB/c mice did not develop ileal immunopathology nor did their parasite loads differ from those in wildtype BALB/c mice. Thus, although Tim-3 is markedly upregulated upon infection and differentially regulated in susceptible and resistant mice upon infection with T. gondii, the absence of Tim-3 is not sufficient to overcome the genetic resistance of BALB/c mice to the development of Th1-driven small intestinal immunopathology.

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Pro-inflammatory potential of Escherichia coli strains K12 and Nissle 1917 in a murine model of acute ileitis
Authors: S. Bereswill, A. Fischer, I. R. Dunay, A. A. Kühl, U. B. Göbel, O. Liesenfeld and M. M. Heimesaat

Abstract

Non-pathogenic Escherichia coli (Ec) strains K12 (EcK12) and Nissle 1917 (EcN) are used for gene technology and probiotic treatment of intestinal inflammation, respectively. We investigated intestinal colonization and potential pro-inflammatory properties of EcK12, EcN, and commensal E. coli (EcCo) strains in Toxoplasma (T.) gondii-induced acute ileitis. Whereas gnotobiotic animals generated by quintuple antibiotic treatment were protected from ileitis, mice replenished with conventional microbiota suffered from small intestinal necrosis 7 days post-T. gondii infection (p.i.). Irrespective of the Ec strain, recolonized mice revealed mild to moderate histopathological changes in their ileal mucosa. Upon stable recolonization with EcK12, EcN, or EcCo, development of inflammation was accompanied by pro-inflammatory responses at day 7 p.i., including increased ileal T lymphocyte and apoptotic cell numbers compared to T. gondii-infected gnotobiotic controls. Strikingly, either Ec strain was capable to translocate to extraintestinal locations, such as MLN, spleen, and liver. Taken together, Ec strains used in gene technology and probiotic treatment are able to exert inflammatory responses in a murine model of small intestinal inflammation. In conclusion, the therapeutic use of Ec strains in patients with broad-spectrum antibiotic treatment and/or intestinal inflammation should be considered with caution.

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Selective gelatinase blockage ameliorates acute DSS colitis
Authors: M. M. Heimesaat, I. R. Dunay, D. Fuchs, D. Trautmann, A. Fischer, A. A. Kühl, C. Loddenkemper, A. Batra, B. Siegmund, H.-W. Krell, S. Bereswill and O. Liesenfeld

Abstract

In the experimental models of intestinal inflammation and humans with inflammatory bowel diseases (IBD), increased levels of the matrix metalloproteinases (MMPs), MMP-2 and -9 (also referred to as gelatinase A and B, respectively), in inflamed tissue sites can be detected. In the presented study, we investigated potential beneficial effects exerted by doxycycline nonselectively blocking MMPs and the selective gelatinase inhibitor RO28-2653 in acute DSS colitis. Treatment with either compound for 8 days ameliorated clinical colitis pathology with a superior outcome in RO28-2653-treated animals. As compared to placebo controls, histopathological changes in the colon were less distinct following MMP blockage and IL-6 secretion in ex vivo biopsies was downregulated, paralleled by a diminished influx of pro-inflammatory immune cells and lack of overgrowth of the colonic lumen by potentially pro-inflammatory Escherichia coli of the commensal colon flora.

We conclude that selective gelatinase inhibition not only exerts beneficial effects by disrupting the vicious cycle of positive feedback between immune cell stimulation and MMP induction but also prevents overgrowth of the colonic lumen by pro-inflammatory E. coli despite a lack of direct anti-bacterial properties, thus unaffecting the commensal gut microbiota. These findings put RO28-2653 into a center stage for development of intervention strategies in human IBD.

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The distinct roles of MMP-2 and MMP-9 in acute DSS colitis
Authors: Markus M. Heimesaat, I. R. Dunay, D. Fuchs, D. Trautmann, A. Fischer, A. A. Kühl, C. Loddenkemper, B. Siegmund, A. Batra, S. Bereswill and O. Liesenfeld

Abstract

Expression of gelatinases A and B, also referred to matrixmetalloproteinases (MMP)-2 and -9, respectively, is increased in inflamed tissues of experimental intestinal inflammation and humans with inflammatory bowel disease (IBDs). Given that we recently reported that treatment with the selective gelatinase inhibitor RO28-2653 ameliorates acute dextrane sulfate sodium (DSS) colitis, we asked whether gelatinase A or B expression is pivotal in mediating large intestinal inflammation. Results from our study reveal that symptoms of acute DSS colitis as well as histopathological colonic changes were ameliorated in MMP-2-, but not MMP-9-deficient mice, and were paralleled by a diminished influx of immune cells. In MMP-2-deficient mice, we observed lower expression of pro-inflammatory cytokines including interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and IL-6 in colonic biopsies and less overgrowth of the colonic lumen by potentially pro-inflammatory enterobacteria from the commensal gut microbiota. We conclude that rather MMP-2 than MMP-9 is causative for the establishment of DSS colitis in mice. The discrepancy of these data to prior reports might be due to substantial differences in the intestinal microbiota composition of the mice bred at different animal facilities impacting susceptibility to inflammatory stimuli. Consequently, a detailed survey of the gut microbiota should be implemented in immunological/inflammatory studies in the future in order to allow comparison of data from different facilities.

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High seroprevalence of Toxoplasma gondii infection in inmates: A case control study in Durango City, Mexico
Authors: Cosme Alvarado-Esquivel, J. Hernández-Tinoco, L. F. Sánchez-Anguiano, A. Ramos-Nevárez, S. M. Cerrillo-Soto, L. Sáenz-Soto and O. Liesenfeld

Abstract

Purpose:

The seroprevalence of infection with the parasite Toxoplasma gondii and the association with risk factors has not been determined in inmates. Through a case-control study, 166 inmates from a state correctional facility in Durango City, Mexico and 166 age- and gender-matched non-incarcerated subjects were examined for the presence of anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays.

Results:

Seroprevalence of anti-T. gondii IgG antibodies was higher in inmates (35, 21.1%) than in controls (14, 8.4%) (OR = 2.90; 95% CI: 1.43–5.94; P = 0.001). Anti-T. gondii IgM antibodies were detected in two (1.2%) inmates and in seven (4.2%) controls (P = 0.17). Multivariate analysis of socio-demographic, incarceration, and behavioral characteristics of inmates revealed that T. gondii seropositivity was associated with being born out of Durango State (OR = 3.91; 95% CI: 1.29–11.79; P = 0.01). In addition, T. gondii seroprevalence was higher (P = 0.03) in inmates that had suffered from injuries (17/56: 30.4%) than those without such history (18/110: 16.4%).

Conclusions:

The seroprevalence of T. gondii infection in inmates in Durango City is higher than the seroprevalences found in the general population in the same city, indicating that inmates may represent a new risk group for T. gondii infection. Further research on T. gondii infection in inmates is needed.

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Miscarriage history and Toxoplasma gondii infection: A cross-sectional study in women in Durango City, Mexico
Authors: Cosme Alvarado-Esquivel, S. J. Pacheco-Vega, J. Hernández-Tinoco, M. M. Centeno-Tinoco, I. Beristain-García, L. F. Sánchez-Anguiano, O. Liesenfeld, E. Rábago-Sánchez and L. O. Berumen-Segovia

Abstract

Through a cross-sectional study design, 326 women with a history of miscarriage were examined for anti-Toxoplasma gondii IgG and IgM antibodies in Durango City, Mexico. Prevalence association with sociodemographic, clinical, and behavioral characteristics in women with miscarriage was also investigated.

Twenty-two (6.7%) of the 326 women studied had anti-T. gondii IgG antibodies and two (0.6%) were also positive for anti-T. gondii IgM antibodies. Seroprevalence of T. gondii infection was not influenced by age, birth place, occupation, educational level, or socioeconomic status. In contrast, logistic regression showed that T. gondii exposure was associated with consumption of raw or undercooked meat (OR = 6.84; 95% CI: 1.04–44.95; P = 0.04) and consumption of chicken brains (OR = 18.48; 95% CI: 1.26–269.43; P = 0.03).

This is the first study on the seroepidemiology of T. gondii infection in women with a history of miscarriage in Northern Mexico. Of interest, we also observed an association of T. gondii exposure with consumption of chicken brains. Contributing factors for T. gondii exposure found in the present study should be taken into consideration for public health measures to avoid infection with T. gondii and its sequelae.

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Liquid and dry swabs for culture- and PCR-based detection of colonization with methicillin-resistant Staphylococcus aureus during admission screening
Authors: N. von Allmen, K. Gorzelniak, O. Liesenfeld, M. Njoya, J. Duncan, E. M. Marlowe, T. Hartel, A. Knaust, B. Hoppe and M. Walter

Rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) colonization status facilitates isolation and decolonization and reduces MRSA infections. Liquid but not dry swabs allow fully automated detection methods. However, the accuracy of culture and polymerase chain reaction (PCR) using liquid and dry swabs has not been analyzed. We compared different swab collection systems for routine nasal–throat MRSA screening in patients admitted to a tertiary care trauma center in Germany. Over 3 consecutive months, dry swabs (month 1), ESwabs (month 2), or MSwabs (month 3) were processed using Cepheid GeneXpert, Roche cobas and BD-MAX™ MRSA tests compared to chromogenic culture. Among 1680 subjects, the MRSA detection rate using PCR methods did not differ significantly between dry swabs, ESwab, and MSwab (6.0%, 6.2%, and 5.3%, respectively). Detection rates using chromogenic culture were 2.9%, 3.9%, and 1.9%, using dry, ESwab, and MSwab, respectively. Using chromogenic culture as the “gold standard”, negative predictive values for the PCR tests ranged from 99.2–100%, and positive predictive values from 33.3–54.8%. Thus, efficient and accurate MRSA screening can be achieved using dry, as well as liquid E- or MSwab, collection systems. Specimen collection using ESwab or MSwab facilitates efficient processing for chromogenic culture in full laboratory automation while also allowing molecular testing in automated PCR systems.

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