Immunogenic molecules associated with gut bacterial cell walls: chemical structures, immune-modulating functions, and mechanisms

Interactions between gut microbiome and host immune system are fundamental to maintaining the intestinal mucosal barrier and homeostasis. At the host-gut microbiome interface, cell wall-derived molecules from gut commensal bacteria have been reported to play a pivotal role in training and remodeling host immune responses. In this article, we review gut bacterial cell wall-derived molecules with characterized chemical structures, including peptidoglycan and lipid-related molecules that impact host health and disease processes via regulating innate and adaptive immunity. Also, we aim to discuss the structures, immune responses, and underlying mechanisms of these immunogenic molecules. Based on current advances, we propose cell wall-derived components as important sources of medicinal agents for the treatment of infection and immune diseases.

Long-read sequencing revealed alterations of microbial relationship between tongue coating and gastric mucosa in patients with gastric intestinal metaplasia / 数字中医药（英文）

Objective@#To explore the microbial correlation between oral tongue coating (TC) and gastric mucosa (GM) in patients with gastric intestinal metaplasia (GIM).@*Methods@#The present study recruited 1360 volunteers for upper gastrointestinal cancer screening. The microbiota in TC and GM were profiled by long-read sequencing of full-length 16S rRNA gene. The microbial diversity, community structure, and linear discriminant analysis effect size (LEfSe) were analyzed by the software Visual Genomics. SparCC correlation analysis was used to construct the commensal network and the graphical display was conducted by R software.@*Results@#The population included 44 patients with precancerous GIM, and 28 matched controls with negative rapid urease test (RUT) and non-symptomatic chronic superficial gastritis (CSG). No significant difference in diversity was observed between GIM patients and controls in TC or GM microbiota (P > 0.05). Patients had a higher percentage of 41 – 60 co-occurring operational taxonomic units (OTUs) between TC and GM than controls (34.1% vs. 25.0%) (P < 0.05). The LEfSe showed that TC Prevotella melaninogenica and three gastric Helicobacter species (i.e., Helicobacter pylori, Helicobacter pylori XZ274, and Helicobacter pylori 83) were enriched in patients with GIM. Furthermore, GIM patients with positive RUT had a lower percentage of co-occurring OTUs over 20 (P < 0.05), and lower abundances of gastric Veillonella, Pseudonocardia, and Mesorhizobium than those with negative RUT (P < 0.05). The commensal network between TC and GM was more complex in GIM patients than in controls. GIM patients with positive RUT demonstrated more bacterial correlations between TC and GM than those with negative RUT. Finally, the serum ratio of PG-I/II was negatively correlated with three gastric Helicobacter species (Helicobacter pylori, Helicobacter pylori XZ274, and Helicobacter pylori 83) in patients with negative RUT (P < 0.05), and negatively correlated with two TC species (Fusobacterium nucleatum subsp. nucleatum and Campylobacter showae) in patients with positive RUT (P < 0.05).@*Conclusion@#The development of GIM potentiated the commensal network between oral TC and GM, providing microbial evidence of the correlation between TC and the stomach.

Dysbiosis of lung commensal bacteria in the process of lung epithelial-mesenchymal transition in mice with silicosis / 中国职业医学

@#Objective - To investigate the effect of lung flora dysbiosis on the process of pulmonary fibrosis and lung epithelial （ ） Methods - mesenchymal transition EMT in mice with silicosis. Male C57BL/6 mice of specific pathogen free grade were ， ， ， （ ） randomly divided into the blank control group silicosis model group solvent control group vancomycin VM + ampicillin （ ） ， （ ） （ ） ， AMP group metronidazole MNZ + neomycin NEO group and mixed treatment group 12 mice in each group. Except for ， ， the blank control group which was given 20.0 µL of 0.9% NaCl solution the other five groups of mice were dosed with 20.0 µL of silica dust suspension at a mass concentration of 250.0 g/L using a single tracheal drip to establish the silicosis mouse model. ： The intranasal drip method was used to treat silicosis mice in each group as following mice in the solvent control group were - ； ； given double distilled water mice in the VM+AMP group were given VM at a mass concentration of 0.5 g/L and AMP at 1.0 g/L ； mice in the MNZ+NEO group were given MNZ at a mass concentration of 1.0 g/L and NEO at 1.0 g/L mice in the mixed ， treatment group were given the same doses of the four antibiotics mentioned above all in a drip volume of 50.0 µL. Silicosis ， ， mice were treated seven days and half an hour before silica dusting and 7 14 and 21 days after silica dusting. Mouse lungtissue was collected aseptically 28 days after silica dusting. Hematoxylin eosin and Masson trichrome staining methods were - used to observe the pathological changes. Western blotting was used to detect the relative protein expression of α smooth muscle （ - ）， - （ - ） （ ） actin α SMA E cadherin E CAD and vimentin VIM . Immunohistochemistry was used to detect the relative expression of - - E CAD and VIM. Real time fluorescence quantitative polymerase chain reaction was used to detect the expression levels of （Col1a2） Results collagen type Ⅰ alpha 2 mRNA in lung tissues. The histopathological results showed that the alveoli of the ， blank control group were thin and structurally intact with few surrounding infiltrating inflammatory cells and no abnormal ， distribution of collagen fibers. The alveoli of the silicosis model group were structurally disorganized with a large number of ， ， infiltrating inflammatory cells thickened alveolar walls and cellular fibrous nodules with abundant blue collagen deposit. In the ， ， VM+AMP group MNZ+NEO group and the mixed treatment group the inflammation and fibrosis were reduced with diferent degrees in the lung tissues compared to the silicosis model group and the solvent control group. The relative expression levels of - ， Col1a2 α SMA VIM protein and mRNA in lung tissues of mice in the silicosis model group were higher than those in the blank （ P ）， -CAD control group all <0.05 and the relative expression levels of E protein were lower than those in the blank control （P ） - ， Col1a2 group <0.05 . The relative expression levels of α SMA VIM protein and mRNA in lung tissues of mice in the MNZ+ （ P ）， -CAD NEO group and the mixed treatment group were lower all <0.05 and the relative expression levels of E protein were （P ）， Conclusion higher <0.05 when compared with the silicosis model group and the solvent control group. Pulmonary fibrosis ， - was reduced in silicosis mice with interventions in lung flora where anaerobic and gram negative bacteria affected pulmonary fibrosis and dysbiosis of the lung flora affected pulmonary EMT.

Isolation and identification of multidrug-resistant Escherichia coli from cattle, sheep, poultry and human in Cumilla, Bangladesh

Aims@#Antimicrobial resistance (AMR) is a significant public health concern of modern civilization. The potential risk of AMR is significant in terms of both human and animal health. This study aims to assess the antimicrobial resistance pattern of selected antimicrobials against Escherichia coli of animal, poultry and human origin in the Cumilla district of Bangladesh.@*Methodology and results@#A total of 200 samples were collected from different sources. Isolation and identification of commensal E. coli were performed following standard bacteriological and molecular techniques. Antimicrobial susceptibility testing was performed following the Kirby-Bauer disc diffusion technique. Ampicillin, tetracycline and sulfamethoxazole-trimethoprim resistance genes were detected by polymerase chain reactions (PCR). A total of 152 (76%; 95% confidence interval (CI) 70-81%) E. coli were isolated from cattle, sheep, chicken and human, where 37.5% of isolates were found to be multidrug-resistant (MDR). In the cultural sensitivity test, E. coli showed the highest resistance to sulfamethoxazole-trimethoprim (71%), tetracycline (63%), ampicillin (62%), where gentamicin (23%) showed the lowest resistance, followed by ceftriaxone (26%). The prevalence of resistance genes like blaTEM, tetA, tetB, tetC, sul1 and sul2 were 100%, 95%, 11%, 8%, 58% and 52%, respectively.@*Conclusion, significance and impact of study@#The emergence of multidrug-resistant commensal E. coli and resistance genes circulating in animals, poultry and humans limit the treatment options for serious infections.

Occurrence of Hymenolepis diminuta: a potential helminth of zoonotic importance in murid rodents / Ocorrência de Hymenolepis diminuta: um helminto potencial de importância zoonótica em roedores murídeos

The study reveals the prevalence of a potential rodent-borne zoonotic helminth species, Hymenolepis diminuta in commensal rodents caught from irrigated and rain-fed areas of Swat, Pakistan. Three hundred and fifty rodents (269 rats and 81 mice) trapped during vegetative, flowering/fruiting and mature/harvesting stages of crops were studied from 2011-2013. Hymenolepisdiminuta eggs were identified on the basis of their shape, size, colour and markings on the surface of the egg shell and three pairs of embryonic hook-lets. Overall prevalence of H. diminuta was 3.14% (n=11/350). The highest prevalence 3.49% (n=5/143) of H. diminuta was noted at harvesting stages of the crops whereas the lowest 2.59% (n=2/77) during vegetative stage. Infection was higher in males 3.25% (n=7/215) than females 2.96% (n=4/135). Adult rodents were highly infected while no sub-adult was found infected. Infection was higher in mice 3.70% (3/81) than rats 2.69% (8/269) while no significance (p=1.0000:0.1250 to 32.00 CI). Rats and mice appears to show the most suitable reservoirs by hosting H. diminuta a zoonotic helminth. The presence of these rodents in all possible habitats can act as a main channel of transferring parasites through various habitats and can pose a hazard to humans in the area.

O estudo revela a prevalência de uma espécie potencial de helmintos zoonóticos transmitidos por roedores, Hymenolepis diminuta, em roedores comensais capturados em áreas irrigadas e alimentadas pela chuva de Swat, Paquistão. Trezentos e cinquenta roedores (269 ratos e 81 camundongos) presos durante os estágios vegetativo, floração/frutificação e maturidade/colheita das safras foram estudados de 2011-2013. Ovos de Hymenolepisdiminuta foram identificados com base em sua forma, tamanho, cor e marcações na superfície da casca do ovo e três pares de anzóis embrionários. A prevalência geral de H. diminuta foi de 3,14% (n = 11/350). A maior prevalência 3,49% (n = 5/143) de H. diminuta foi observada na fase de colheita das lavouras, enquanto a menor 2,59% (n = 2/77) durante a fase vegetativa. A infecção foi maior nos homens 3,25% (n = 7/215) do que nas mulheres 2,96% (n = 4/135). Roedores adultos foram altamente infectados, enquanto nenhum subadulto foi encontrado infectado. A infecção foi maior em camundongos 3,70% (3/81) do que em ratos 2,69% (8/269), embora sem significância (p = 1,0000: 0,1250 a 32,00 CI). Ratos e camundongos parecem mostrar os reservatórios mais adequados hospedando H. diminuta um helmintos zoonótico. A presença desses roedores em todos os habitats possíveis pode atuar como um canal principal de transferência de parasitas através de vários habitats e pode representar um perigo para os humanos na área.

Occurrence of Hymenolepis diminuta: a potential helminth of zoonotic importance in murid rodents

Abstract The study reveals the prevalence of a potential rodent-borne zoonotic helminth species, Hymenolepis diminuta in commensal rodents caught from irrigated and rain-fed areas of Swat, Pakistan. Three hundred and fifty rodents (269 rats and 81 mice) trapped during vegetative, flowering/fruiting and mature/harvesting stages of crops were studied from 2011-2013. Hymenolepisdiminuta eggs were identified on the basis of their shape, size, colour and markings on the surface of the egg shell and three pairs of embryonic hook-lets. Overall prevalence of H. diminuta was 3.14% (n=11/350). The highest prevalence 3.49% (n=5/143) of H. diminuta was noted at harvesting stages of the crops whereas the lowest 2.59% (n=2/77) during vegetative stage. Infection was higher in males 3.25% (n=7/215) than females 2.96% (n=4/135). Adult rodents were highly infected while no sub-adult was found infected. Infection was higher in mice 3.70% (3/81) than rats 2.69% (8/269) while no significance (p=1.0000:0.1250 to 32.00 CI). Rats and mice appears to show the most suitable reservoirs by hosting H. diminuta a zoonotic helminth. The presence of these rodents in all possible habitats can act as a main channel of transferring parasites through various habitats and can pose a hazard to humans in the area.

Resumo O estudo revela a prevalência de uma espécie potencial de helmintos zoonóticos transmitidos por roedores, Hymenolepis diminuta, em roedores comensais capturados em áreas irrigadas e alimentadas pela chuva de Swat, Paquistão. Trezentos e cinquenta roedores (269 ratos e 81 camundongos) presos durante os estágios vegetativo, floração/frutificação e maturidade/colheita das safras foram estudados de 2011-2013. Ovos de Hymenolepisdiminuta foram identificados com base em sua forma, tamanho, cor e marcações na superfície da casca do ovo e três pares de anzóis embrionários. A prevalência geral de H. diminuta foi de 3,14% (n = 11/350). A maior prevalência 3,49% (n = 5/143) de H. diminuta foi observada na fase de colheita das lavouras, enquanto a menor 2,59% (n = 2/77) durante a fase vegetativa. A infecção foi maior nos homens 3,25% (n = 7/215) do que nas mulheres 2,96% (n = 4/135). Roedores adultos foram altamente infectados, enquanto nenhum subadulto foi encontrado infectado. A infecção foi maior em camundongos 3,70% (3/81) do que em ratos 2,69% (8/269), embora sem significância (p = 1,0000: 0,1250 a 32,00 CI). Ratos e camundongos parecem mostrar os reservatórios mais adequados hospedando H. diminuta um helmintos zoonótico. A presença desses roedores em todos os habitats possíveis pode atuar como um canal principal de transferência de parasitas através de vários habitats e pode representar um perigo para os humanos na área.

Occurrence of Hymenolepis diminuta: a potential helminth of zoonotic importance in murid rodents / Ocorrência de Hymenolepis diminuta: um helminto potencial de importância zoonótica em roedores murídeos

The study reveals the prevalence of a potential rodent-borne zoonotic helminth species, Hymenolepis diminuta in commensal rodents caught from irrigated and rain-fed areas of Swat, Pakistan. Three hundred and fifty rodents (269 rats and 81 mice) trapped during vegetative, flowering/fruiting and mature/harvesting stages of crops were studied from 2011-2013. Hymenolepisdiminuta eggs were identified on the basis of their shape, size, colour and markings on the surface of the egg shell and three pairs of embryonic hook-lets. Overall prevalence of H. diminuta was 3.14% (n=11/350). The highest prevalence 3.49% (n=5/143) of H. diminuta was noted at harvesting stages of the crops whereas the lowest 2.59% (n=2/77) during vegetative stage. Infection was higher in males 3.25% (n=7/215) than females 2.96% (n=4/135). Adult rodents were highly infected while no sub-adult was found infected. Infection was higher in mice 3.70% (3/81) than rats 2.69% (8/269) while no significance (p=1.0000:0.1250 to 32.00 CI). Rats and mice appears to show the most suitable reservoirs by hosting H. diminuta a zoonotic helminth. The presence of these rodents in all possible habitats can act as a main channel of transferring parasites through various habitats and can pose a hazard to humans in the area.

O estudo revela a prevalência de uma espécie potencial de helmintos zoonóticos transmitidos por roedores, Hymenolepis diminuta, em roedores comensais capturados em áreas irrigadas e alimentadas pela chuva de Swat, Paquistão. Trezentos e cinquenta roedores (269 ratos e 81 camundongos) presos durante os estágios vegetativo, floração/frutificação e maturidade/colheita das safras foram estudados de 2011-2013. Ovos de Hymenolepis diminuta foram identificados com base em sua forma, tamanho, cor e marcações na superfície da casca do ovo e três pares de anzóis embrionários. A prevalência geral de H. diminuta foi de 3,14% (n = 11/350). A maior prevalência 3,49% (n = 5/143) de H. diminuta foi observada na fase de colheita das lavouras, enquanto a menor 2,59% (n = 2/77) durante a fase vegetativa. A infecção foi maior nos homens 3,25% (n = 7/215) do que nas mulheres 2,96% (n = 4/135). Roedores adultos foram altamente infectados, enquanto nenhum subadulto foi encontrado infectado. A infecção foi maior em camundongos 3,70% (3/81) do que em ratos 2,69% (8/269), embora sem significância (p = 1,0000: 0,1250 a 32,00 CI). Ratos e camundongos parecem mostrar os reservatórios mais adequados hospedando H. diminuta um helmintos zoonótico. A presença desses roedores em todos os habitats possíveis pode atuar como um canal principal de transferência de parasitas através de vários habitats e pode representar um perigo para os humanos na área.

Arthropods associated with a Bombus pauloensis (Hymenoptera: Apidae: Bombini) nest in the Sabana of Bogotá (Colombia) / Artrópodos asociados a un nido de Bombus pauloensis (Hymenoptera: Apidae: Bombini) en la Sabana de Bogotá (Colombia)

ABSTRACT Bumblebees are important natural pollinators due to their services to wild and cultivated plants. They commonly nest in cavities in the ground where they are exposed to numerous organisms or interact with them. One Bombus pauloensis nest in the Sabana of Bogotá (Colombia) was transferred to an artificial nest and relocated close to a honeybee apiary after the original nest was threatened by an intentional fire. The objective was to preserve the colony and simultaneously identify arthropods associated with a bumblebee nest as this is poorly studied in Colombia. Samples of the organisms found in the bumblebees' nest were collected for taxonomic identification. Several commensal, scavenger and parasitic organisms were found, including Antherophagus sp. (Coleoptera: Crytophagidae), wireworm beetles (Coleoptera: Elateride), Fannia canicularis (Diptera: Fanniidae), and mites of genera Parasitellus and Pneumolaelaps. This is the first report of other organisms besides Antherophagus from a B. pauloensis nest in Colombia.

RESUMEN Los abejorros son polinizadores importantes en la naturaleza, debido a que prestan su servicio a plantas silvestres y cultivadas. Naturalmente, anidan en cavidades en el suelo, donde se pueden exponer a una gran variedad de organismos o interactuar con estos. Un nido de Bombus pauloensis en la Sabana de Bogotá fue transferido a un nido artificial y reubicado cerca de un apiario, debido a que el nido original fue quemado intencionalmente. Se tuvo por objetivo preservar la colonia e identificar los artrópodos asociados, ya que son poco estudiados en Colombia. Se tomaron muestras de los organismos encontrados en el nido, para determinación taxonómica. Varios organismos con hábitos comensales, descomponedores y parásitos se encontraron, incluyendo Antherophagus sp. (Coleoptera: Crytophagidae), cucarrones del gusano alambre (Coleoptera: Elateride), Fannia canicularis (Diptera: Fanniidae) y ácaros de los géneros Parasitellus y Pneumolaelaps (Acarina). Este es el primer reporte de otros organismos, diferentes de Antherophagus, para un nido de B. pauloensis, en Colombia.

Relationships between Virulence Factors and Antimicrobial Resistance among Escherichia coli Isolated from Urinary Tract Infections and Commensal Isolates in Tehran, Iran

OBJECTIVES: Uropathogenic Escherichia coli (UPEC) are the major cause of urinary tract infections (UTIs). Here, we determined whether sensitivity to antibiotics was related to the prevalence of iron scavenging genes, or to biofilm and hemolysis formation. METHODS: A total of 110 UPEC and 30 E coli isolates were collected from the urine of UTI patients and feces of healthy individuals without UTI, respectively. The presence of iron receptor genes and phenotypic properties were evaluated by polymerase chain reaction and phenotypic methods, respectively. Susceptibility to routine antibiotics was evaluated using the disc diffusion method. RESULTS: The prevalence of iron scavenging genes ranged from 21.8% (ireA) to 84.5% (chuA) in the UPEC. Resistance to ceftazidime and cefotaxime was significantly correlated with the presence of fyuA and iutA iron genes. Biofilm production was significantly associated with the prevalence of fyuA and hma iron genes. A higher degree of antibiotic resistance was exhibited by isolates that produced biofilms than by their non-biofilm producing counterparts. CONCLUSION: Our study clearly indicates that biofilm production is associated with antibiotic resistance, and that iron receptors and hemolysin production also contribute to reduced antibiotic sensitivity. These results further our understanding of the role that these virulence factors play during UPEC pathogenesis, which in turn may be valuable for the development of novel treatment strategies against UTIs.

Diversity and antimicrobial susceptibility of cultivable commensal bacteria from 18 to 22 year-old healthy people's nose and skin / 中华检验医学杂志

Objective To investigate the diversity and antimicrobial susceptibility of cultivable commesal bacteria from 18 to 22 year-old healthy people′s nose and skin. Methods From June to August 2017,18 to 22 year-old healthy people (n=210) were swabbed on skin and nose and cultured with blood plates at Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Species determination was performed using matrix assisted laser desorption Lonization-time of flight-mass spectrometry(MALDI-TOF-MS);Susceptibility testing was performed on the major species by the disc diffusion method; Genomic characteristics of methicillin resistant Staphylococcus epidermidis(MRSE) were determined by pulsed field gel electrophoresis (PFGE) method;SCCmec typing was tested by polymerase chain reaction(PCR);Statistical analysis was performed using SPSS software and association statistics were tested using Chi-Square tests. Results In total, 25 genera were identified of cultivable bacteria from 210 healthy people′s nose (1497 isolates) and skin (941 isolates).Staphylococcus isolates from nose and skin accounted for 82.03% and 80.23% respectively.Eleven species were identified of all Staphylococcus isolates and coagulase-negative Staphylococci(CoNS)from nose and skin accounted for 90.72% and 99.21% respectively.Furthermore, a variety of other species and differences between men and women were observed. Susceptibility testing was done on 631 Staphylococcus isolates, which were sensitive to most antibiotics but show high prevalence of resistance towards penicillin (76.55%), erythromycin (41.20%), clindamycin (10.77%) and trimethoprim/sulfamethoxazole(10.14%). Methicillin Resistant Staphylococcus (MRS) (45 isolates) showed higher prevalence of resistance towards penicillin (χ2=12.17,P<0.001), erythromycin (χ2=10.80,P=0.001), levofloxacin (χ2=20.24, P<0.001) and trimethoprim/sulfamethoxazole (χ2=58.57,P<0.001) compared to methicillin sensitive Staphylococcus (MSS)(586 isolates). Moreover, multidrug resistance (MDR) was observed in 42.16% of 631 isolates and MRS showed a significantly higher proportion than MSS(100.00% vs 37.71%,χ2=66.49,P<0.001).PFGE generated 23 groups out of 33 MRSE isolates. SCCmec genotyping of MRSE showed the most prevalent type was SCCmecⅣ (66.67%). Conclusions Obvious genus and species diversity and genetic diversity were observed on cultivable bacteria from 18 to 22 year-old healthy people′s nose and skin,and CoNS was in the majority. Staphylococcus isolates from healthy people′s nose and skin were sensitive to most antibiotics,but show high prevalence of resistance towards penicillin, erythromycin, clindamycin and trimethoprim/sulfamethoxazole. In addition, MDR was serious especially in MRS. Commensal bacteria may act as reservoir for resistance genes facilitating bacteria infection.

Mannheimia haemolytica growth and leukotoxin production for vaccine manufacturing: a bioprocess review

Mannheimia haemolytica leukotoxin (LKT) is a known cause of bovine respiratory disease (BRD) which results in severe economic losses in the cattle industry (up to USD 1 billion per year in the USA). Vaccines based on LKT offer the most promising measure to contain BRD outbreaks and are already commercially available. However, insufficient LKT yields, predominantly reflecting a lack of knowledge about the LKT expression process, remain a significant engineering problem and further bioprocess optimization is required to increase process efficiency. Most previous investigations have focused on LKT activity and cell growth, but neither of these parameters defines reliable criteria for the improvement of LKT yields. In this article, we review the most important process conditions and operational parameters (temperature, pH, substrate concentration, dissolved oxygen level, medium composition and the presence of metabolites) from a bioprocess engineering perspective, in order to maximize LKT yields.

Beyond Hygiene: Commensal Microbiota and Allergic Diseases

Complex communities of microorganisms, termed commensal microbiota, inhabit mucosal surfaces and profoundly influence host physiology as well as occurrence of allergic diseases. Perturbing factors such as the mode of delivery, dietary fibers and antibiotics can influence allergic diseases by altering commensal microbiota in affected tissues as well as in intestine. Here, we review current findings on the relationship between commensal microbiota and allergic diseases, and discuss the underlying mechanisms that contribute to the regulation of allergic responses by commensal microbiota.

Progress in regulation of intestinal immune homeostasis / 中华微生物学和免疫学杂志

A healthy gut consists of commensal flora,epithelial layer and gut-associated lymphoid tissue (GALT). GALT is hyporesponsive to commensal flora and dietary antigens,but can recognize and at-tack pathogens. Accumulating evidence suggests that dendritic cells (DCs) play a crucial role in managing this paradoxical situation and maintaining the complex homeostasis in gut. Influenced by intestinal epithelial cells (IECs) and commensal flora,intestinal DCs possess unique properties that enable them to regulate T-helper 2 (Th2) cells,regulatory T cells (Tregs) and immunoglobulin A (IgA)-producing cells in a steady state. During infection,intestinal DCs are involved in the induction of effector lymphocytes, although they are also responsible for initiating pathogenic responses in inflammatory bowel diseases (IBDs). Therefore, intestinal DCs are associated with not only the maintenance of immune tolerance to commensal flora,but also the induction of protective immune responses against pathogens. This review outlines the roles of commensal flora, epithelial layer, and GALT in mucosal homeostasis and inflammation and summarizes recent progress in DCs-mediated intestinal immune homeostasis.

Quantitative analysis of intestinal bacteria in Caenorhabditis elegans using qPCR / 军事医学

Objective To establish a method for detecting intestinal bacteria in Caenorhabditis elegans.Methods The gut flora number of 1, 20 or, 50 C.elegans was quantified and compared using real-time quantitative PCR (qPCR). Results The gut flora of a single C.elegans could be detected using qPCR method , which could also reflect the difference in the number of gut bacteria between different samples .Conclusion The qPCR method can be uased to accurately quantify intestinal bacteria even in only one C.elegans and has the advantages of low-cost, high-sensitivity and good-specificity.

Commensal Fungi are Involved in Antigen-Specific Antibody Production in the Elderly.

Aims: Fungi are an important health hazard as commensal antigens. To demonstrate sensitization to fungi in the elderly and the influence of prohibition of oral intake under intravenous hyperalimentation (IVH) management with administration of antibiotics, we measured commensal fungus-specific antibodies. Methodology: Thirty one college students (21.7±1.0 years): Young adult group, 28 elderly subjects over 75 years from the outpatient department (84.3±4.5 years): Outpatient group, and 21 elderly subjects over 75 years who were inpatients and required IVH (87.6±6.0 years): Inpatient group were enrolled. Plasma β-D-glucan and serum total immunoglobulin (Ig) E, antigen-specific IgE for house dust (HD), Cladosporium, Alternaria, Trichophyton, and Candida and Candidaspecific IgG were measured. Results: Total IgE level was significantly decreased in the outpatient group compared to the young adult group (p＜0.01), and was increased in the inpatient group compared to the outpatient group (p＜0.05). HD-specific IgE was elevated in the young group compared to the two elderly groups (p＜0.01, respectively). There was no tendency for detection of Cladosporium-or Alternaria-specific IgE in the three groups. Tricophyton-specific IgE level was significantly elevated in the inpatient group compared to the young adult group (p＜0.01). Candida-specific IgE level was significantly elevated in the inpatient group compared to the outpatient group (p＜0.05). Candida-specific IgG was significantly elevated in the inpatient group compared to the other two groups (p＜0.001, respectively). Conclusion: It is suggested that commensal fungi, such as Trichophyton and Candida, are more markedly associated with antigen-specific immunoglobulin production in an immunocompromised condition in the elderly.

Study progresses in respiratory mucosal immunity and related diseases / 中国免疫学杂志

As the passage of environmental atmosphere entering the body,the respiratory tract suffers persistent challenge from foreign substances.The mucosal immune system of the respiratory tract is the main defense line against the invasion of pathogens,which needs to distinguish not only beneficial and detrimental materials but also resident and pathogenic bacteria.Because the knowledge about respiratory mucosal immunity is limited,the immunopathologic mechanisms of related diseases such as asthma,acute lung injury, chronic obstructive pulmonary disease, and respiratory infection need investigation.The study about the immune features of the respiratory tract not only contributes to the prevention and treatment of respiratory disease but also provides ideas for the development and design of new vaccines and medicines.

Enterococci: A journey of a successful pathogen.

Introduction: A dynamic homeostasis is maintained between the host and native bacteria of the gastrointestinal tract in humans, but migration of bacteria from the gut to other organs can lead to disease or death. Enterococci, traditionally viewed as commensal bacteria are now acknowledged to be organisms capable of causing life-threatening infections in humans, especially in the nosocomial environment. The existence of Enterococci in such a dual role is facilitated by its intrinsic and acquired resistance to virtually all antibiotics currently in use. Objective: The present pilot study was taken up to compare the multidrug resistance prevalence in commensal Enterococci and pathogenic Enterococci. Material and methods: A total of 50 commensal Enterococci isolated from stool samples and 50 clinical samples yielding Enterococci were taken for the study. Antibiotic susceptibility testing was done using Kirby Bauer’s disk diffusion method. Minimum inhibitory concentration of Vancomycin was tested by using E- strip. Results: Among 50 commensal Enterococci, majority showed resistance to Ampicillin 50 (100%), Erythromycin 38 (76%), Clindamycin 30 (60%), higher level of resistance to high level Gentamycin 14 (28%), Linezolid 6 (12%), vancomycin 3 (6%). 23 (46%) isolates showed multi drug resistance (resistance to ≥ 3 categories of antibiotics). Among 50 clinical isolates, majority showed resistance to Ampicillin 50 (100%), Erythromycin 38 (76%), Clindamycin 30 (60%), higher level of resistance to high level Gentamycin 14 (28%), Linezolid 6 (12%), vancomycin 3 (6%). 23 (46%) isolates showed multi drug resistance (resistance to ≥ 3 categories of antibiotics). Among 50 clinical isolates, majority showed resistance to Ampicillin 50 (100%), Clindamycin 46 (92%), Tetracycline 46 (92%), Erythromycin 41 (82%), Linezolid resistance was seen in 8 (16%) and Vancomycin resistance in 5(10%) clinical isolate. 48(96%) showed multi drug resistance. Conclusion: Boundary line between pathogenic and commensal Enterococci is blurred due to exchange of resistant traits. Regular screening of enterococcal isolates for resistance detection should be implemented. It is very important to consider infection control measures, screening of health care workers, surveillance cultures which can control spread of multidrug resistant Enterococci.

Prevalencia de Blastocystis sp. y otros protozoarios comensales en individuos de Santa Rosa de Agua, Maracaibo, estado Zulia / Prevalence of Blastocystis sp. and other commensal protozoa in individuals from Santa Rosa del Agua, Zulia State

Con la finalidad de determinar la prevalencia de Blastocystis sp. y especies de protozoarios comensales intestinales del hombre según diferentes aspectos como la edad y el sexo, se evaluaron muestras de heces de 111 individuos varones y mujeres de todas las edades, pobladores de Santa Rosa de Agua, Maracaibo, estado Zulia. Cada muestra fecal se analizó a través de un examen al fresco, tinción de lugol y técnica de concentración de Ritchie. Se utilizó la tinción de hematoxilina férrica para identificar trofozoitos de Dientamoeba fragilis. Las especies del complejo Entamoeba histolytica/Entamoeba dispar se diferenciaron mediante técnicas de PCR. Blastocystis sp. fue la especie predominante (45,6%), seguida por Entamoeba coli (17,9%), Endolimax nana (14,8%), Chilomastix mesnili (6,2%), Entamoeba dispar (5,6%), Dientamoeba fragilis, Pentatrichomonas hominis, Iodamoeba butschlii (3,1%) respectivamente y Entamoeba hartmanni (0,6%). Hubo afinidad parasitaria entre las especies Entamoeba coli y Endolimax nana. No se demostró asociación entre presencia de infección y sexo. Los grupos etarios preescolares y escolares demostraron asociación significativa con la infección parasitaria. Se determinó una elevada prevalencia de Blastocystis sp. y especies comensales intestinales, todas indicadoras de contaminación fecal, donde probablemente factores ambientales y socioculturales promovieron su transmisión.

With the purpose of determining Blastocytis sp. and other commensal intestinal protozoa species prevalence according to different aspects such as age and sex, we evaluated 111 feces samples from male and female individuals of all ages, living at Santa Rosa del Agua, Maracaibo, Zulia State, Venezuela. Each fecal sample was analyzed fresh, stained with lugol, and by Ritchie’s concentration test. We used ferric hematoxilin stain to identify Dientamoeba fragilis trophozoites. Species belonging to the Entamoeba histolytica/Entamoeba dispar complex were differentiated through PCR techniques. Blastocytis sp. was the predominant species (45.6%), followed by Entamoeba coli (17.9%), Endolimax nana (14.8%), Chilomastix mesnili (6.2%), Entamoeba dispar (5.6%), Dientamoeba fragilis, Pentatrichomonas hominis, Iodamoeba butschlii (3.1%, respectively), and Entamoeba hartmanni (0.6%). There was parasitic affinity between the Entamoeba coli and Endolimax nana species. There was no association between presence of infection and sex. Pre-school and school age groups showed a significant association with parasite infection. A high prevalence of Blastocystis sp. and intestinal commensal species was determined, all indicative of fecal contamination, where environmental and sociocultural factors probably promote transmission.

Predictors for abundance of Rattus tanezumi in households of commensal rodent plague foci / 中华流行病学杂志

Objective To explore the predictors on the abundance of Rattus (R.) tanezumi in households of commensal rodent plague foci.Methods Thirty natural villages that experienced previous plague cases in Lianghe county,Yunnan province,were selected followed by random selection of 20 households in each village through computer technique.Live traps were set in households to capture small mammals which were then identified to species in the field according to their morphological features.Data on potential factors for abundance of R.tanezumi were collected through questionnaires and field observation and were coded and computerized using EpiData software and further analyzed by hurdle regression model under R software.Results A total of 166 rodents (133 R.tanezumi and 33 Suucus murinus) were captured.Results from final multilevel hurdle regression model showed that the likelihood of R.tanezumi captures increased by 1.67-to 2.76-fold in households belonged to Dai ethnic families that stored foodstuff in metal pails,often raising dogs,and having adjacent houses.The number of R.tanezumi captures increased by 2.18-fold in the villages where over 80％ of the households would raise chickens.In the villages with communal latrine,the likelihood and the number of R.tanezumi capture increased 1.93-fold and 2.38-fold,respectively.While the likelihood of R.tanezumi captures would reduce by 45％-61％ in those households where there were cats and cattle being raised and maize grown in the village.The number of R.tanezumi captures would reduce by 63％ in the households where there were outside toilets.Conclusion The abundance of R.tanczumi seemed to be closely related to the ecological environment factors.Programs on plague control and prevention should relate to ecological factors that influencing the abundance of R.tanezumi.

Detection of Enzootic Plague Foci in Peninsular India.

A Continuous serological and bacteriological surveillance in rodents was carried out in peninsular India i.e. Andhra Pradesh, Karnataka and Tamil Nadu to detect the role of different species of rodents in the maintenance of active enzootic plague foci. Live rodents were collected from wild and ruderal/peri-domestic situations by digging and trapping for sera and organ samples. During 1989 to 2007 serological evidence of plague was detected in different species of rodents in peninsular India. Plague antibodies were detected in 243 sera samples in three different rodent species. Sero-positivity (0.042 percent) amongst rodents tested were found in Tatera indica cuvieri (Hardwicke) followed by Rattus rattus and Bandicota bengalensis. Regular plague surveillance work enhanced the possibility of detecting and delimiting plague foci and helped in implementing necessary preventive anti plague measures to prevent the occurrence of human plague.