Authors:Cosme Alvarado-Esquivel, Luis Francisco Sánchez-Anguiano, Alejandra Mendoza-Larios, Jesús Hernández-Tinoco, José Francisco Pérez-Ochoa, Elizabeth Irasema Antuna-Salcido, Elizabeth Rábago-Sánchez, and Oliver Liesenfeld
The presence of tissue cysts of Toxoplasma gondii has only poorly been investigated in autopsy series. We determined the presence of T. gondii cysts in a series of 51 autopsies in a public hospital using immunohistochemistry of brain and heart tissues. The association of tissue cysts with the general characteristics of the autopsy cases was also investigated.
Of the 51 cases studied, five (9.8%) were positive by immunohistochemistry for T. gondii cysts in the brain. None of the heart specimens was positive for T. gondii cysts. The presence of T. gondii cysts in brains did not vary with age, sex, birthplace, residence, education, occupation, or the presence of pathology in the brain. In contrast, multivariate analysis showed that the presence of T. gondii cysts was associated with undernourishment (OR = 33.90; 95% CI: 2.82–406.32; P = 0.005).
We demonstrated cerebral T. gondii cysts in an autopsy series in Durango City, Mexico. Results suggest that T. gondii can be more readily found in brain than in heart of infected individuals. This is the first report of an association between the presence of T. gondii in brains and undernourishment.
Authors:C. Alvarado-Esquivel, S. J. Pacheco-Vega, M. Salcedo-Jaquez, L. F. Sánchez-Anguiano, J. Hernández-Tinoco, E. Rábago-Sánchez, M. M. Centeno-Tinoco, I. D. Flores-Garcia, A. Ramos-Nevarez, S. M. Cerrillo-Soto, C. A. Guido-Arreola, I. Beristain-García, O. Liesenfeld, L. O. Berumen-Segovia, L. Saenz-Soto, and A. Sifuentes-Álvarez
Through a cross-sectional study design, 150 women attending public health centers with a history of stillbirths were examined for anti-Toxoplasma gondii IgG and IgM antibodies in Durango City, Mexico. Bivariate and multivariate analyses were used to assess the association of T. gondii seropositivity with the characteristics of the women with stillbirth history.
Of the 150 women (mean age: 32.09 ± 9.16 years) studied, 14 (9.3%) had anti-T. gondii IgG antibodies and six (42.9%) of them were also positive for anti-T. gondii IgM antibodies. Multivariate analysis showed that T. gondii seropositivity was associated with high frequency (4–7 days a week) of eating meat (OR = 5.52; 95% CI: 1.48–20.59; P = 0.01), history of lymphadenopathy (OR = 4.52; 95% CI: 1.14–17.82; P = 0.03), and history of surgery (OR = 8.68; 95% CI: 1.04–72.15; P = 0.04).
This is the first study on the seroepidemiology of T. gondii infection in women with a history of stillbirths in Mexico. The association of T. gondii exposure with a history of surgery warrants for further research. Risk factors for T. gondii infection found in the present survey may help to design optimal educational programs to avoid T. gondii infection.
A fully functioning immune system is essential in order to maintain good health. However, the immune system deteriorates with advancing age, and this contributes to increased susceptibility to infection, autoimmunity, and cancer in the older population. Progress has been made in identifying age-related defects in the adaptive immune system. In contrast, relatively little research has been carried out on the impact of ageing on the innate immune response. This area requires further research as the innate immune system plays a crucial role in protection against infection and represents a first line of defence. Macrophages are central effector cells of the innate immune system and have many diverse functions. As a result, age-related impairments in macrophage function are likely to have important consequences for the health of the older population. It has been reported that ageing in macrophages impacts on many processes including toll-like receptor signalling, polarisation, phagocytosis, and wound repair. A detailed understanding of the impact of ageing on macrophages is required in order to develop therapeutics that will boost immune responses in the older population.
Authors:Manja Boehm, Judith Lind, Steffen Backert, and Nicole Tegtmeyer
Campylobacter jejuni is an important pathogen of foodborne illness. Transmigration across the intestinal epithelial barrier and invasion are considered as primary reasons for tissue damage triggered by C. jejuni. Using knockout mutants, it was shown that the serine protease HtrA may be important for stress tolerance and physiology of C. jejuni. HtrA is also secreted in the extracellular environment, where it can cleave junctional host cell proteins such as E-cadherin. Aim of the present study was to establish a genetic complementation system in two C. jejuni strains in order to introduce the wild-type htrA gene in trans, test known htrA phenotypes, and provide the basis to perform further mutagenesis. We confirm that reexpression of the htrA wild-type gene in ΔhtrA mutants restored the following phenotypes: 1) C. jejuni growth at high temperature (44 °C), 2) growth under high oxygen stress conditions, 3) expression of proteolytically active HtrA oligomers, 4) secretion of HtrA into the supernatant, 5) cell attachment and invasion, and 6) transmigration across polarized epithelial cells. These results establish a genetic complementation system for htrA in C. jejuni, exclude polar effects in the ΔhtrA mutants, confirm important HtrA properties, and permit the discovery and dissection of new functions.
Malignantly transformed (cancer) cells of multicellular hosts, including human cells, operate activated biochemical pathways that recognizably derived from unicellular ancestors. The descendant heat shock proteins of thermophile archaea now chaperon oncoproteins. The ABC cassettes of toxin-producer zooxantella Symbiodinia algae pump out the cytoplasmic toxin molecules; malignantly transformed cells utilize the derivatives of these cassettes to get rid of chemotherapeuticals. High mobility group helix-loop-helix proteins, protein arginine methyltransferases, proliferating cell nuclear antigens, and Ki-67 nuclear proteins, that protect and repair DNA in unicellular life forms, support oncogenes in transformed cells. The cell survival pathways of Wnt–β-catenin, Hedgehog, PI3K, MAPK–ERK, STAT, Ets, JAK, Pak, Myb, achaete scute, circadian rhythms, Bruton kinase and others, which are physiological in uni- and early multicellular eukaryotic life forms, are constitutively encoded in complex oncogenic pathways in selected single cells of advanced multicellular eukaryotic hosts. Oncogenes and oncoproteins in advanced multicellular hosts recreate selected independently living and immortalized unicellular life forms, which are similar to extinct and extant protists. These uni cellular life forms are recognized at the clinics as autologous “cancer cells”.
Authors:B. Wangala, A. Vovor, R. Gantin, Y. Agbeko, C. Lechner, X. Huang, Peter Soboslay, and C. Köhler
Chemokine a nd antibody response profiles were investigated in children and adults with severe or uncomplicated Plasmodium falciparum malaria; the aim was to reveal which profiles are associated with severe disease, as often seen in nonimmune children, or with mild and uncomplicated disease, as seen in semi-immune adults. Blood samples were obtained from children under 5 years of age as well as adults with falciparum malaria. Classification of malaria was performed according to parasite densities and hemoglobin concentrations. Plasma levels of chemokines (IL-8, IP-10, MCP-4, TARC, PARC, MIP-1δ, eotaxins) were quantified, and antibody responses (IgE, IgG1, and IgG4) to P. falciparum, Entamoeba histolytica-specific antigen, and mite allergen extracts were determined. In children with severe malaria proinflammatory, IL-8, IP10, MIP-1δ, and LARC were at highly elevated levels, suggesting an association with severe disease. In contrast, the Th2-type chemokines TARC, PARC, and eotaxin-2 attained in children the same levels as in adults suggesting the evolution of immune regulatory components. In children with severe malaria, an elevated IgG1 and IgE reactivity to mite allergens and intestinal protozoan parasites was observed. In conclusion, exacerbated proinflammatory chemokines together with IgE responses to mite allergens or E. histolytica-specific antigen extract were observed in children with severe falciparum malaria.
Authors:Hagen Frickmann, Rebecca Hinz, and Ralf Hagen
Here, we assessed the extraction efficiency of a deployable bench-top nucleic acid extractor EZ1 in comparison to the column-based approach with complex sample matrices.A total of 48 EDTA blood samples and 81 stool samples were extracted by EZ1 automated extraction and the column-based QIAamp DNA Mini Kit. Blood sample extractions were assessed by two real-time malaria PCRs, while stool samples were analyzed by six multiplex real-time PCR assays targeting bacterial, viral, and parasitic stool pathogens. Inhibition control PCR testing was performed as well.In total, 147 concordant and 13 discordant pathogen-specific PCR results were obtained. The latter comprised 11 positive results after column-based extraction only and two positive results after EZ1 extraction only. EZ1 extraction showed a higher frequency of inhibition. This phenomenon was, however, inconsistent for the different PCR schemes. In case of concordant PCR results, relevant differences of cycle threshold numbers for the compared extraction schemes were not observed.Switches from well-established column-based extraction to extraction with the automated EZ1 system do not lead to a relevantly reduced yield of target DNA when complex sample matrices are used. If sample inhibition is observed, column-based extraction from another sample aliquot may be considered.
Authors:Olubenga Olowe, B. Ojo-Johnson, O. Makanjuola, R. Olowe, and V. Mabayoje
Human immunodeficiency virus-positive individuals are at increased risk of both asymptomatic and symptomatic urinary tract infections. The aim of this study was to determine the prevalence of asymptomatic bacteriuria (ASB) in HIV-positive individuals, its associated factors including any correlation with the CD4 count of the patient, and the antibiotic susceptibility pattern of the isolated organisms. Midstream urine and blood samples were collected from 242 consenting HIV-positive patients who were attending routine follow-up clinic during the six-month period of the study. Microscopy, culture, and antibiotic susceptibility testing of the samples were carried out following standard protocols, and CD4 counts were also determined. Fifty one (21.1%) of the 242 individuals had significant bacteriuria. The predominant organism was Klebsiella spp. (35%) followed by Escherichia coli (31%). Prevalence of bacteriuria was higher in the women. Low CD4 counts and young age were significantly associated with the presence of bacteriuria. ASB prevalence is high in this population and related to the CD4 count level.
Authors:Rebecca Hinz, Andreas Zautner, Ralf Hagen, and Hagen Frickmann
Haemophilus influenzae is a key pathogen of upper respiratory tract infections. Its reliable discrimination from nonpathogenic Haemophilus spp. is necessary because merely colonizing bacteria are frequent at primarily unsterile sites. Due to close phylogenetic relationship, it is not easy to discriminate H. influenzae from the colonizer Haemophilus haemolyticus. The frequency of H. haemolyticus isolations depends on factors like sampling site, patient condition, and geographic region.Biochemical discrimination has been shown to be nonreliable. Multiplex PCR including marker genes like sodC, fucK, and hpd or sequencing of the 16S rRNA gene, the P6 gene, or multilocus-sequence-typing is more promising. For the diagnostic routine, such techniques are too expensive and laborious. If available, matrix-assisted laser-desorption-ionization time-of-flight mass spectrometry is a routine-compatible option and should be used in the first line. However, the used database should contain well-defined reference spectra, and the spectral difference between H. influenzae and H. haemolyticus is small. Fluorescence in-situ hybridization is an option for less well-equipped laboratories, but the available protocol will not lead to conclusive results in all instances. It can be used as a second line approach. Occasional ambiguous results have to be resolved by alternative molecular methods like 16S rRNA gene sequencing.
Authors:Sofia Stokkou, Gernot Geginat, Dirk Schlüter, and Ina Tammer
Sepsis represents a life-threatening infection requiring the immediate start of antibacterial treatment to reduce morbidity. Thus, laboratories use direct antimicrobial susceptibility testing (AST) to rapidly generate preliminary results from positive blood cultures. As the direct AST has not yet been published to be evaluated with EUCAST breakpoints, the purpose of the study was to investigate the reliability of the direct agar diffusion test to correctly produce AST results from positive monobacterial blood cultures compared with the VITEK2-based definitive AST, when current EUCAST breakpoints were used.A total of 428 isolates from unselected monobacterial routine blood cultures and 110 challenge strains were included. Direct agar diffusion-based and standard VITEK2-based AST of 2803 bacterium-drug combinations yielded a total clinical category agreement of 95.47% with 1.28% very major errors and 3.42% combined major and minor errors. On the species level, very major errors were observed in the species-drug combinations Enterococcus spp.-high-level gentamicin (10.87%) and Staphylococcus spp.-rifampicin (5%), only. No very major errors occurred with Enterobacteriaceae and Pseudomonas aeruginosa.In most species-drug combinations, the direct agar diffusion test using EUCAST breakpoints precisely predicted the result of the definitive antibiotic susceptibility test and, thus, it can be used to optimize empiric antibiotic therapy until definitive results are available.