Microbiota Signals during the Neonatal Period Forge Life-Long Immune Responses.

The microbiota regulates immunological development during early human life, with long-term effects on health and disease. Microbial products include short-chain fatty acids (SCFAs), formyl peptides (FPs), polysaccharide A (PSA), polyamines (PAs), sphingolipids (SLPs) and aryl hydrocarbon receptor (AhR) ligands. Anti-inflammatory SCFAs are produced by Actinobacteria, Bacteroidetes, Firmicutes, Spirochaetes and Verrucomicrobia by undigested-carbohydrate fermentation. Thus, fiber amount and type determine their occurrence. FPs bind receptors from the pattern recognition family, those from commensal bacteria induce a different response than those from pathogens. PSA is a capsular polysaccharide from B. fragilis stimulating immunoregulatory protein expression, promoting IL-2, STAT1 and STAT4 gene expression, affecting cytokine production and response modulation. PAs interact with neonatal immunity, contribute to gut maturation, modulate the gut-brain axis and regulate host immunity. SLPs are composed of a sphingoid attached to a fatty acid. Prokaryotic SLPs are mostly found in anaerobes. SLPs are involved in proliferation, apoptosis and immune regulation as signaling molecules. The AhR is a transcription factor regulating development, reproduction and metabolism. AhR binds many ligands due to its promiscuous binding site. It participates in immune tolerance, involving lymphocytes and antigen-presenting cells during early development in exposed humans.

Outer Membrane Vesicles (OMVs) Produced by Gram-Negative Bacteria: Structure, Functions, Biogenesis, and Vaccine Application.

Gram-negative bacteria produce outer membrane vesicles (OMVs) with 10 to 300 nm of diameter. The contribution of OMVs to bacterial pathogenesis is a topic of great interest, and their capacity to be combined with antigens impact in the future to the development of vaccines.

Chemical Composition and Antibacterial Effect of Plantago Major Extract on Periodontal Pathogens

Abstract Objective: To determine the in vitro antibacterial effect of different concentrations of the ethanol extract of Plantago major (plantain) on Porphyromonas gingivalis and Fusobacterium nucleatum. Material and Methods: Bacterial susceptibility tests were used in conjunction with the agar diffusion test and the minimum inhibitory concentration (MIC) test using the broth macrodilution technique. Results: Different concentrations of ethanol extract (25%, 50%, 75% and 100%) dissolved in 70% ethanol were used, with a positive control (0.12% chlorhexidine + 0.05% cetyl-pyridinium chloride) and a negative control (70% alcohol). The extracts at 75% and 100% showed inhibition halos against both strains studied. With 0.12% chlorhexidine + 0.05% cetyl-pyridinium chloride, inhibition halos averaged 14.9 mm, in contrast to 70º alcohol, where no bacterial inhibition was observed. The MIC was 50% for both species. Conclusion: The ethanol extract of Plantago major presents an in vitro antibacterial effect on Porphyromonas gingivalis, they may have potential applications in food and pharmaceutical products.

Risk Factors for Early Childhood Caries Based on Identification of Veillonella spp. Using RT-PCR

Abstract Objective: To identify the occurrence of Veillonella spp. in children using real-time PCR (RT-PCR) and to determine its role as a risk factor for ECC in children aged 2-3 years. Material and Methods: A cross-sectional survey was conducted and samples from 87 children aged 2-3 years, who lived in selected villages in the Bandung City area, Indonesia, were collected. Examination for dental caries was performed using standard checks for decay, missing, and filled surfaces (dfms), and saliva samples were taken. Microbiological examination was performed using RT-PCR with primers consisting of one primary set for Veillonella spp. and one universal primary set for 16S rDNA. We performed statistical testing using the Mann Whitney rank-sum test. Results: A total of 87 children were sampled, and an ECC prevalence of 71.3% was found, with a mean dmfs of 7.1 (± 9.1). The proportion of Veillonella spp. in caries-free children was 2.13 ± 2.30, while in children with ECC, it was 3.29 ± 6.83. Conclusion: The proportion of Veillonella spp. in children with ECC was higher than in caries-free children; therefore, Veillonella spp. may be a risk factor for ECC.

Beyond the antibody: B cells as a target for bacterial infection.

It is well established that B cells play an important role during infections beyond antibody production. B cells produce cytokines and are APCs for T cells. Recently, it has become clear that several pathogenic bacterial genera, such as Salmonella, Brucella, Mycobacterium, Listeria, Francisella, Moraxella, and Helicobacter, have evolved mechanisms such as micropinocytosis induction, inflammasome down-regulation, inhibitory molecule expression, apoptosis induction, and anti-inflammatory cytokine secretion to manipulate B cell functions influencing immune responses. In this review, we summarize our current understanding of B cells as targets of bacterial infection and the mechanisms by which B cells become a niche for bacterial survival and replication away from extracellular immune responses such as complement and antibodies.

Functionality of the Interleukin 8 haplotypes in lymphocytes and macrophages in response to gram-negative periodontopathogens.

Individuals carrying the ATC/TTC haplotype (Hap-1) in the interleukin 8 (IL8) gene were reported as more susceptible to chronic periodontitis (CP), an infectious disease associated with Gram-negative bacteria, in comparison to patients with the ATT/TTC haplotype (Hap-2). This study investigated the functionality of the IL8 haplotypes in lymphocytes and monocytes of individuals carrying the Hap-1 or Hap-2 IL8 haplotypes in the response to CP-associated Gram-negative bacteria (periodontopathogens). Peripheral blood was collected from 6 subjects carrying each haplotype, and their immune cells were challenged with periodontopathogens or phorbol 12-myristate 13-acetate (PMA) plus Ionomycin. Depending on the immune cell type (lymphocytes or monocyte-derived macrophages) the assessed outcomes were: phenotypical polarization, gene expression, phagocytic activity, chemotaxis and production of reactive oxygen species (ROS). Subjects carrying the Hap-1 haplotype showed increased expression of IL8 and TNFA and significantly skewing towards pro-inflammatory Th1/M1/Th17 phenotypes. There was increased percentage of ROS-producing monocyte-derived macrophages from individuals carrying the Hap-1 haplotype. Cells from individuals presenting the Hap-2 haplotype had an overall attenuated response to periodontopathogens, with a significant shift towards the Treg phenotype. In conclusion, the IL8 haplotypes showed to be functional both in monocyte-derived macrophages and lymphocytes. The Hap-1 haplotype previously associated with increased susceptibility to CP demonstrated greater skewing to pro-inflammatory Th1/M1/Th17 phenotypes and production of ROS.

Isolation of Fungi and Gram Negative Bacteria from Toothbrushes and Bathroom Bioaerosols

Objective: To identify, using phenotypic methods, FGNB, NFGNB and Candida sp. in toothbrushes, and environmental samples of bathroom air in a group of students from the Dentistry School of the Universidad Central de Venezuela. Material and Methods: Thirty-four toothbrushes were supplied to the cohort during a 60-day period; environmental samples were collected in the rooms where toothbrushes were kept during this period. All samples were processed by traditional methods of microbiological counting isolation and phenotypic identification using selective and differential agar based on the international guidelines of the United States Pharmacopeia (USP) 38. Results: 82.36% of the toothbrush samples were positive to bacteria and fungi and 91.17% of the environmental samples were positive to enterobacteria. Conclusion: It is necessary to establish antiseptic protocols for the management, storage and disinfection of toothbrushes. The high rate of contamination may represent an opportunity for enterobacteria colonization of oral biofilms, reservoir to infection foci and metastatic infections in certain populations.

Inflammasome-dependent Mechanisms Involved in Sensing and Restriction of Bacterial Replication.

Inflammasomes are multiprotein platforms assembled in the cytosol in response to pathogens and cell stress. Inflammasomes are recognized by their important role on defenses against bacterial infections and have been also implicated in a range of human inflammatory disorders. Intracellular sensors such as NLRP1, NLRP3, NLRC4, AIM2 and Pyrin induce assembly of inflammasomes, while caspase-11 induces the non-canonical pathway for activation of the NLRP3 inflammasome. The formation of the inflammasome leads to caspase-1 activation that triggers pyroptosis and activation of interleukin-1ß (IL-1ß) and IL-18. Pyroptotic cell death and cytokines production are involved in restriction of bacterial replication by limiting the replication niche of intracellular bacteria and by inducing inflammatory responses. In this review we focus on the mechanisms mediated by inflammasome activation that leads to inflammatory responses and restriction of bacterial infection.

The immunotranscriptome of the Caribbean reef-building coral Pseudodiploria strigosa.

The viability of coral reefs worldwide has been seriously compromised in the last few decades due in part to the emergence of coral diseases of infectious nature. Despite important efforts to understand the etiology and the contribution of environmental factors associated to coral diseases, the mechanisms of immune response in corals are just beginning to be studied systematically. In this study, we analyzed the set of conserved immune response genes of the Caribbean reef-building coral Pseudodiploria strigosa by Illumina-based transcriptome sequencing and annotation of healthy colonies challenged with whole live Gram-positive and Gram-negative bacteria. Searching the annotated transcriptome with immune-related terms yielded a total of 2782 transcripts predicted to encode conserved immune-related proteins that were classified into three modules: (a) the immune recognition module, containing a wide diversity of putative pattern recognition receptors including leucine-rich repeat-containing proteins, immunoglobulin superfamily receptors, representatives of various lectin families, and scavenger receptors; (b) the intracellular signaling module, containing components from the Toll-like receptor, transforming growth factor, MAPK, and apoptosis signaling pathways; and (3) the effector module, including the C3 and factor B complement components, a variety of proteases and protease inhibitors, and the melanization-inducing phenoloxidase. P. strigosa displays a highly variable and diverse immune recognition repertoire that has likely contributed to its resilience to coral diseases.

Identification and antimicrobial resistance of members from the Enterobacteriaceae family isolated from canaries (Serinus canaria) / Identificação e resistência antimicrobiana de membros da família Enterobacteriaceae isolados de canários (Serinus canaria)

The Enterobacteriaceae family contains potentially zoonotic bacteria, and their presence in canaries is often reported, though the current status of these in bird flocks is unknown. Therefore, this study aimed to identify the most common genera of enterobacteria from canaries (Serinus canaria) and their antimicrobial resistance profiles. From February to June of 2013, a total of 387 cloacal swab samples from eight domiciliary breeding locations of Fortaleza city, Brazil, were collected and 58 necropsies were performed in canaries, which belonged to the Laboratory of Ornithological Studies. The samples were submitted to microbiological procedure using buffered peptone water and MacConkey agar. Colonies were selected according to their morphological characteristics on selective agar and submitted for biochemical identification and antimicrobial susceptibility. A total of 61 isolates were obtained, of which 42 were from cloacal swabs and 19 from necropsies. The most isolated bacteria was Escherichia coli with twenty five strains, followed by fourteen Klebsiellaspp., twelve Enterobacterspp., seven Pantoea agglomerans, two Serratiaspp. and one Proteus mirabilis. The antimicrobial to which the strains presented most resistance was sulfonamides with 55.7%, followed by ampicillin with 54.1% and tetracycline with 39.3%. The total of multidrug-resistant bacteria (MDR) was 34 (55.7%). In conclusion, canaries harbor members of the Enterobacteriaceae family and common strains present a high antimicrobial resistance rate, with a high frequency of MDR bacteria.(AU)

A família Enterobacteriaceae possui bactérias com potencial zoonótico e a presença destas bactérias em canários é relatada na literatura, porém a realidade dos plantéis de criadores de canários é desconhecida. Portanto, este trabalho teve como objetivo isolar enterobactérias de canários belga (Serinus canarius) com o intuito de conhecer os gêneros mais comuns nestas aves e suas respectivas resistências a antimicrobianos. De fevereiro a junho de 2013 foram coletadas 387 amostras de swabs cloacais de canários de oito propriedades da cidade de Fortaleza, Brasil e de 58 necropsias de aves do acervo próprio do Laboratório de Estudos Ornitológicos. As amostras foram submetidas a isolamento microbiológico utilizando-se água peptonada e ágar MacConkey. As colônias foram selecionadas de acordo com suas características morfológicas nas placas, submetidas à tipificação bioquímica para identificação e ao teste de sensibilidade a antimicrobianos. Foram isoladas 61 cepas, sendo 42 de suabes cloacais e 19 de necropsias. A bactéria mais isolada foi Escherichia coli com vinte e cinco cepas, seguida por catorze Klebsiella spp., doze Enterobacter spp., sete Pantoea agglomerans, duas Serratiaspp. e uma cepa de Proteus mirabilis. As cepas apresentaram maior resistência a sulfonamidas com 55,7%, seguidas por ampicilina com 54,1% e tetraciclina com 39,3%. Além disso, o total de cepas resistentes a múltiplas drogas (RMD) foi 34 (55,7%). Portanto, conclui-se que os canários albergam enterobactérias e que as cepas apresentam alto índice de resistência a antimicrobianos, com alta frequência de cepas RMD.(AU)

Identification and antimicrobial resistance of members from the Enterobacteriaceae family isolated from canaries (Serinus canaria) / Identificação e resistência antimicrobiana de membros da família Enterobacteriaceae isolados de canários (Serinus canaria)

The Enterobacteriaceae family contains potentially zoonotic bacteria, and their presence in canaries is often reported, though the current status of these in bird flocks is unknown. Therefore, this study aimed to identify the most common genera of enterobacteria from canaries (Serinus canaria) and their antimicrobial resistance profiles. From February to June of 2013, a total of 387 cloacal swab samples from eight domiciliary breeding locations of Fortaleza city, Brazil, were collected and 58 necropsies were performed in canaries, which belonged to the Laboratory of Ornithological Studies. The samples were submitted to microbiological procedure using buffered peptone water and MacConkey agar. Colonies were selected according to their morphological characteristics on selective agar and submitted for biochemical identification and antimicrobial susceptibility. A total of 61 isolates were obtained, of which 42 were from cloacal swabs and 19 from necropsies. The most isolated bacteria was Escherichia coli with twenty five strains, followed by fourteen Klebsiellaspp., twelve Enterobacterspp., seven Pantoea agglomerans, two Serratiaspp. and one Proteus mirabilis. The antimicrobial to which the strains presented most resistance was sulfonamides with 55.7%, followed by ampicillin with 54.1% and tetracycline with 39.3%. The total of multidrug-resistant bacteria (MDR) was 34 (55.7%). In conclusion, canaries harbor members of the Enterobacteriaceae family and common strains present a high antimicrobial resistance rate, with a high frequency of MDR bacteria.

A família Enterobacteriaceae possui bactérias com potencial zoonótico e a presença destas bactérias em canários é relatada na literatura, porém a realidade dos plantéis de criadores de canários é desconhecida. Portanto, este trabalho teve como objetivo isolar enterobactérias de canários belga (Serinus canarius) com o intuito de conhecer os gêneros mais comuns nestas aves e suas respectivas resistências a antimicrobianos. De fevereiro a junho de 2013 foram coletadas 387 amostras de swabs cloacais de canários de oito propriedades da cidade de Fortaleza, Brasil e de 58 necropsias de aves do acervo próprio do Laboratório de Estudos Ornitológicos. As amostras foram submetidas a isolamento microbiológico utilizando-se água peptonada e ágar MacConkey. As colônias foram selecionadas de acordo com suas características morfológicas nas placas, submetidas à tipificação bioquímica para identificação e ao teste de sensibilidade a antimicrobianos. Foram isoladas 61 cepas, sendo 42 de suabes cloacais e 19 de necropsias. A bactéria mais isolada foi Escherichia coli com vinte e cinco cepas, seguida por catorze Klebsiella spp., doze Enterobacter spp., sete Pantoea agglomerans, duas Serratiaspp. e uma cepa de Proteus mirabilis. As cepas apresentaram maior resistência a sulfonamidas com 55,7%, seguidas por ampicilina com 54,1% e tetraciclina com 39,3%. Além disso, o total de cepas resistentes a múltiplas drogas (RMD) foi 34 (55,7%). Portanto, conclui-se que os canários albergam enterobactérias e que as cepas apresentam alto índice de resistência a antimicrobianos, com alta frequência de cepas RMD.

Expression of IL-8, IL-6 and IL-1ß in tears as a main characteristic of the immune response in human microbial keratitis.

Corneal infections are frequent and potentially vision-threatening diseases, and despite the significance of the immunological response in animal models of microbial keratitis (MK), it remains unclear in humans. The aim of this study was to describe the cytokine profile of tears in patients with MK. Characteristics of ocular lesions such as size of the epithelial defect, stromal infiltration, and hypopyon were analyzed. Immunological evaluation included determination of interleukine (IL)-1ß, IL-6, IL-8, IL-10, IL-12 and tumor necrosis factor (TNF)-α in tear samples obtained from infected eyes of 28 patients with MK and compared with their contralateral non-infected eyes. Additionally, frequency of CD4+, CD8+, CD19+ and CD3-CD56+ cells was also determined in peripheral blood mononuclear cells in patients with MK, and compared with 48 healthy controls. Non-significant differences were observed in the size of the epithelial defect, stromal infiltration, and hypopyon. Nevertheless, we found an immunological profile apparently related to MK etiology. IL-8 > IL-6 in patients with bacterial keratitis; IL-8 > IL-6 > IL-1ß and increased frequency of circulating CD3-CD56+ NK cells in patients with gram-negative keratitis; and IL-8 = IL-6 > IL-1ß in patients with fungal keratitis. Characterization of tear cytokines from patients with MK could aid our understanding of the immune pathophysiological mechanisms underlying corneal damage in humans.

La pubertad en niños chilenos muestra un adelantamiento en el inicio del crecimiento testicular / Age of onset of puberty in Chilean boys according to testicular volume and Tanner stage

Background: A secular trend towards a younger age of puberty onset has been reported in Chilean girls. Aim: To evaluate the age of onset of puberty and prevalence of early puberty in Chilean boys. Material and Methods: A pediatric endocrinologist examined 319 children attending schools in central Santiago. Pubertal development was assessed by testicular volume (TV) and genital inspection (GI) using Tanner graduation. Precocious and early puberty development was diagnosed if TV ≥ 4 ml or GI > stage 2 occurred in boys younger than 9 years and at 9-10 years of age, respectively. Results: Pubertal onset occurred at 10.2 ± 1.5 years according to TV and at 11.1 ± 1.6 years according to GI (p < 0.01). Before the age of nine, 15.2% of children had a VT ≥ 4 ml, 3% had genital changes in GI and only 3% had both changes simultaneously. Early puberty was observed in 23.8% of children according to TV and 9.5% according to GI. However, no child of less than 11 years old had a TV ≥ 4 ml, genital changes and pubic hair simultaneously. Late pubertal stages occurred at the same age according to both criteria used. Body mass index z score was not associated with the age of pubertal onset. Conclusions: Testicular enlargement occurs one year earlier than changes in genitalia according to inspection. Testicular growth, but not late stages of puberty, are occurring one year earlier than previously reported in Chile 10 years ago.

Bacterial lysates improve the protective antibody response against respiratory viruses through Toll-like receptor 4.

Respiratory viruses cause significant morbidity and mortality in infants and young children worldwide. Current strategies to modulate the immune system and prevent or treat respiratory viral infections in this age group have shown limited success. Here, we demonstrate that a lysate derived from Gram-positive and Gram-negative organisms positively modulates protective antibody responses against both respiratory syncytial virus (RSV) and influenza virus in murine models of infection. Interestingly, despite the complex mixture of Toll-like receptor (TLR) agonists present in the bacterial lysate, the modulatory effects were mostly dependent on TLR4 signaling. Our results indicate that the use of simple formulations of TLR-agonists can significantly improve the immune response against critical pediatric respiratory pathogens.

IgG sera levels against a subset of periodontopathogens and severity of disease in aggressive periodontitis patients: a cross-sectional study of selected pocket sites.

AIMS: To evaluate the association among serum immunoglobulin G (IgG) responses to Aggregatibacter actinomycetemcomitans (Aa) serotypes a, b and c, Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf) and clinical parameters in Aggressive Periodontitis (AP) subjects. Associations between periodontal pathogens and clinical and immunological parameters were also evaluated. METHODS: Thirty-eight subjects diagnosed with generalized AP (GAP) and localized AP (LAP) were included. Ten healthy controls were also evaluated. Clinical parameters were assessed and percentages of subgingival levels of Aa, Pg and Tf (beyond bacterial load), were determined by quantitative real-time polymerase chain reaction. Serum IgG antibody levels against Aa, Pg and Tf were evaluated by enzyme-linked immunosorbent assay. RESULTS: Percentages of Aa, Pg and Tf were significantly higher in AP than in controls. The response to Aa serotype c was higher in LAP subjects than in controls. There were no differences in microbial composition or antibodies responses between GAP and LAP, except for IgG response to Tf. Pg levels were correlated with probing depth (PD), BoP and CAL in GAP but not in LAP subjects. Tf levels correlated with PD and CAL in GAP subjects. In GAP, the infection levels of Aa and Pg correlated with the corresponding IgG levels to Aa serotype c and Pg. CONCLUSION: Given the evidences that IgG response in AP patients correlated with bacterial infection level in GAP, but not in LAP, and that LAP patients lack a response to Tf, despite harbouring this species, our data suggest a difference in host immune defence between these two forms of aggressive periodontitis.

Subversion of inflammasome activation and pyroptosis by pathogenic bacteria.

Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila, and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis.

Efeitos do aditivo do leite materno com ferro sobre as propriedades bacteriostáticas do leite materno / Effects of human milk fortifier with iron on the bacteriostatic properties of breast milk

OBJETIVO: Comparar o crescimento bacteriano em colostro puro e colostro com aditivo do leite materno contendo ferro. MÉTODOS: Foram comparadas 78 amostras de colostro puro ou colostro com adição de aditivo do leite materno contendo ferro para avaliar o crescimento de Escherichia coli, Staphylococcus aureus e Pseudomonas aeruginosa. Para a análise qualitativa, discos de papel-filtro foram imersos em amostras de cada grupo e incubados por 48 horas com 10¹ Unidades Formadoras de Colônias/mL de cada cepa. Para a avaliação quantitativa, 1 mL de cada cepa contendo 10(7) Unidades Formadoras de Colônias/mL foi homogeneizado com 1 mL, tanto de colostro puro quanto de colostro com aditivo do leite materno, espalhado em placa de Petri e incubado a 37ºC. O número de Unidades Formadoras de Colônias foi contado 24 horas depois. RESULTADOS: A análise qualitativa não mostrou nenhuma diferença no crescimento bacteriano. Na avaliação quantitativa, o crescimento de Escherichia coli (EC) no grupo C foi de 29,4±9,7 x 10(6) CFU/mL, enquanto no grupo FM85 foi de 31,2±10,8 x 10(6) CFU/mL. A diferença entre o crescimento médio foi de 1,9±4,9 x 10(6) CFU/mL (p = 0,001). Não houve diferenças no crescimento de Staphylococcus aureus e Pseudomonas aeruginosa. CONCLUSÃO: A adição de ferro a essa concentração reduz a ação bacteriostática do leite materno contra Escherichia coli.

OBJECTIVE: To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier (HMF) containing iron. METHODS: The growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa in 78 samples of pure colostrum or colostrum with added iron-containing HMF was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 10¹ colony forming units (CFUs)/mL of each strain. For quantitative assessment, 1 mL of each strain containing 10(7) CFUs/mL was homogenized with 1 mL of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37ºC. Twenty-four hours later, the number of CFUs was counted. RESULTS: The qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, E. coli growth in the control group was 29.4±9.7 x 10(6) CFU/ mL, while in the HMF group it was 31.2±10.8 x 10(6) CFU/mL. The difference between the average growth was 1.9±4.9 x 10(6) CFU/mL (p = 0.001). There were no differences in S. aureus and P. aeruginosa growth. CONCLUSION: Addition of iron at this concentration reduces breast milk bacteriostatic action against E. coli.

Genetic variations in toll-like receptor 4 in Mexican-Mestizo patients with intra-abdominal infection and/or pneumonia.

Sepsis is a leading cause of death around the world, and 73-83% of all sepsis cases requiring attention in intensive care units are linked to intra-abdominal infection (IAI) or pneumonia. The activation of innate immunity is central to the manifestation of sepsis, and toll-like receptor (TLR) 4 plays an important role in this activation process. The 299G and 399I alleles of TLR4 have been linked with an increased risk of Gram-negative bacteria (GNB) infections and septic shock in some populations. This case-control study evaluated the prevalence of D299G/T399I polymorphisms in Mexican patients with IAI and/or pneumonia and in healthy controls. Genotyping revealed that 1 in 44 patients (2.3%; CI 95%: 0.05-12.0%) and 4 in 126 controls (3.2%; CI 95%: 0.9-7.9%) were heterozygous for both the D299G and T399l polymorphisms (OR: 0.71, CI 95%: 0.01-7.44, p = NS), confirming the co-segregation of these alleles in this population. Furthermore, the patients with a GNB infection and severe sepsis were not carriers of the risk alleles. In summary, this report shows that the frequency of the D299G and T399I polymorphisms in Mexican-Mestizos is lower than anticipated in comparison with other ethnic groups, emphasizing the variable distribution of TLR4 polymorphisms among different populations. Consequently, this study was not able to detect associations between TLR4 polymorphisms and sepsis in this population.

Effects of human milk fortifier with iron on the bacteriostatic properties of breast milk.

OBJECTIVE: To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier (HMF) containing iron. METHODS: The growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa in 78 samples of pure colostrum or colostrum with added iron-containing HMF was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 10(1) colony forming units (CFUs)/mL of each strain. For quantitative assessment, 1 mL of each strain containing 10(7) CFUs/mL was homogenized with 1 mL of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37°C. Twenty-four hours later, the number of CFUs was counted. RESULTS: The qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, E. coli growth in the control group was 29.4±9.7×10(6)CFU/mL, while in the HMF group it was 31.2±10.8×10(6)CFU/mL. The difference between the average growth was 1.9±4.9×10(6)CFU/mL (p=0.001). There were no differences in S. aureus and P. aeruginosa growth. CONCLUSION: Addition of iron at this concentration reduces breast milk bacteriostatic action against E. coli.

On the computational modeling of the innate immune system.

In recent years, there has been an increasing interest in the mathematical and computational modeling of the human immune system (HIS). Computational models of HIS dynamics may contribute to a better understanding of the relationship between complex phenomena and immune response; in addition, computational models will support the development of new drugs and therapies for different diseases. However, modeling the HIS is an extremely difficult task that demands a huge amount of work to be performed by multidisciplinary teams. In this study, our objective is to model the spatio-temporal dynamics of representative cells and molecules of the HIS during an immune response after the injection of lipopolysaccharide (LPS) into a section of tissue. LPS constitutes the cellular wall of Gram-negative bacteria, and it is a highly immunogenic molecule, which means that it has a remarkable capacity to elicit strong immune responses. We present a descriptive, mechanistic and deterministic model that is based on partial differential equations (PDE). Therefore, this model enables the understanding of how the different complex phenomena interact with structures and elements during an immune response. In addition, the model's parameters reflect physiological features of the system, which makes the model appropriate for general use.