Maria Elisa Drago-Serrano

Lactoferrin increases both resistance to Salmonella typhimurium infection and the production of antibodies in mice.

Lactoferrin (Lf) is a multifunctional iron-binding glycoprotein with antibacterial and immunomodulatory activities. The antibacterial influence of orally administered bovine Lf (bLf) against murine infection caused by Salmonella typhimurium (S. typhimurium) has scarcely been explored. In the current study, Balb/c mice were treated orally for 7 days with either 5 or 100mg of bovine lactoferrin (bLf). On day 7 of treatment, mice were intragastrically infected with a lethal or sublethal dose of colony forming units (CFU) of S. typhimurium. During treatment with bLf, feces from mice sublethally infected were harvested daily to prepare fecal suspensions, which were serially diluted and plated onto Salmonella Shigella agar to estimate CFU/g of feces. After sacrificing the animals on day 7, 14 or 21 post-infection, samples of intestinal fluid, Peyers patches (PP), liver and spleen were collected to count the number of CFU by plate dilution. Intestinal secretions were also employed, along with serum samples, to evaluate total IgA, IgG and IgM antibodies, and those against Salmonella surface proteins and bLf by ELISA assay. In lethally infected mice both bLf doses decreased mortality. In sublethally infected mice, both bLf doses decreased bacterial shedding in feces and intestinal fluid, and also reduced bacterial colonization at PP and bacterial translocation in the liver and spleen. Levels of total and those IgG and IgM in serum and IgA in intestinal secretions against Salmonella surface proteins and bLf were enhanced with both doses of bLf. These findings suggest that the effect of bLf against the infection by S. typhimurium in mice may be the result of an antimicrobial activity linked with its modulatory effect on immunocompetent cells (from intestinal and peripheral organs) involved in antibody production.

Lactoferrin: Balancing Ups and Downs of Inflammation Due to Microbial Infections

Lactoferrin (Lf) is a glycoprotein of the primary innate immune-defense system of mammals present in milk and other mucosal secretions. This protein of the transferrin family has broad antimicrobial properties by depriving pathogens from iron, or disrupting their plasma membranes through its highly cationic charge. Noteworthy, Lf also exhibits immunomodulatory activities performing up- and down-regulation of innate and adaptive immune cells, contributing to the homeostasis in mucosal surfaces exposed to myriad of microbial agents, such as the gastrointestinal and respiratory tracts. Although the inflammatory process is essential for the control of invasive infectious agents, the development of an exacerbated or chronic inflammation results in tissue damage with life-threatening consequences. In this review, we highlight recent findings in in vitro and in vivo models of the gut, lung, oral cavity, mammary gland, and liver infections that provide experimental evidence supporting the therapeutic role of human and bovine Lf in promoting some parameters of inflammation and protecting against the deleterious effects of bacterial, viral, fungal and protozoan-associated inflammation. Thus, this new knowledge of Lf immunomodulation paves the way to more effective design of treatments that include native or synthetic Lf derivatives, which may be useful to reduce immune-mediated tissue damage in infectious diseases.

Intermittent fasting promotes bacterial clearance and intestinal IgA production in Salmonella typhimurium-infected mice.

The impact of intermittent fasting versus ad libitum feeding during Salmonella typhimurium infection was evaluated in terms of duodenum IgA levels, bacterial clearance and intestinal and extra‐intestinal infection susceptibility. Mice that were intermittently fasted for 12 weeks or fed ad libitum were infected with S. typhimurium and assessed at 7 and 14 days post‐infection. Next, we evaluated bacterial load in the faeces, Peyers patches, spleen and liver by plate counting, as well as total and specific intestinal IgA and plasmatic corticosterone levels (by immunoenzymatic assay) and lamina propria IgA levels in plasma cells (by cytofluorometry). Polymeric immunoglobulin receptor, α‐ and J‐chains, Pax‐5 factor, pro‐inflammatory cytokine (tumour necrosis factor‐α and interferon‐γ) and anti‐inflammatory cytokine (transforming growth factor‐β) mRNA levels were assessed in mucosal and liver samples (by real‐time PCR). Compared with the infected ad libitum mice, the intermittently fasted infected animals had (1) lower intestinal and systemic bacterial loads; (2) higher SIgA and IgA plasma cell levels; (3) higher mRNA expression of most intestinal parameters; and (4) increased or decreased corticosterone levels on day 7 and 14 post‐infection, respectively. No contribution of liver IgA was observed at the intestinal level. Apparently, the changes following metabolic stress induced by intermittent fasting during food deprivation days increased the resistance to S. typhimurium infection by triggering intestinal IgA production and presumably, pathogen elimination by phagocytic inflammatory cells.

Antibiotic resistance and multidrug‐resistant efflux pumps expression in lactic acid bacteria isolated from pozol, a nonalcoholic Mayan maize fermented beverage

Abstract Pozol is a handcrafted nonalcoholic Mayan beverage produced by the spontaneous fermentation of maize dough by lactic acid bacteria. Lactic acid bacteria (LAB) are carriers of chromosomal encoded multidrug‐resistant efflux pumps genes that can be transferred to pathogens and/or confer resistance to compounds released during the fermentation process causing food spoiling. The aim of this study was to evaluate the antibiotic sensibility and the transcriptional expression of ABC‐type efflux pumps in LAB isolated from pozol that contributes to multidrug resistance. Analysis of LAB and Staphylococcus (S.) aureus ATCC 29213 and ATCC 6538 control strains to antibiotic susceptibility, minimal inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) to ethidium bromide were based in “standard methods” whereas the ethidium bromide efflux assay was done by fluorometric assay. Transcriptional expression of efflux pumps was analyzed by RT‐PCR. LAB showed antibiotic multiresistance profiles, moreover, Lactococcus (L.) lactis and Lactobacillus (L.) plantarum displayed higher ethidium bromide efflux phenotype than S. aureus control strains. Ethidium bromide resistance and ethidium bromide efflux phenotypes were unrelated with the overexpression of lmrD in L. lactics, or the underexpression of lmrA in L. plantarum and norA in S. aureus. These findings suggest that, moreover, the analyzed efflux pumps genes, other unknown redundant mechanisms may underlie the antibiotic resistance and the ethidium bromide efflux phenotype in L. lactis and L. plantarum. Phenotypic and molecular drug multiresistance assessment in LAB may improve a better selection of the fermentation starter cultures used in pozol, and to control the antibiotic resistance widespread and food spoiling for health safety.

The Central Nervous System Modulates the Immune Response to Salmonella

Rafael Campos-Rodriguez1, Andres Quintanar Stephano2, Maria Elisa Drago-Serrano3, Edgar Abarca-Rojano1, Istvan Berczi2,4, Javier Ventura-Juarez5 and Alexandre Kormanovski1 1Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Medicina Instituto Politecnico Nacional 2Departamento de Fisiologia y Farmacologia, Centro de Ciencias Basicas Universidad Autonoma de Aguascalientes, Aguascalientes 3Departamento de Sistemas Biologicos Universidad Autonoma Metropolitana Unidad Xochimilco 4Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg 5Departamento de Morfologia, Centro de Ciencias Basicas Universidad Autonoma de Aguascalientes, Aguascalientes 1,2,3,5Mexico 4Canada

Lactoferrin as an Adjunctive Agent in the Treatment of Bacterial Infections Associated with Diabetic Foot Ulcers

Lactoferrin is a protein of mammalian origin secreted in the milk of several animals, including human beings, cows, horses, pigs, goats and mice (Masson & Heremans, 1971). From the moment that bovine (Tomita et al., 2009) and human lactoferrin (Weinberg, 2001) were isolated from the milk of their respective species, they began to receive great attention due to their multifunctional properties that are distinctive from lactoferrin from other mammals. In general, lactoferrin is regarded as a modulator of humoral and cellular components involved in inflammatory and immune responses (Actor et al., 2009; Legrand et al., 2004), which has broad implications. For instance, lactoferrin displays antimicrobial activity against a wide range of pathogens, including virus, bacteria, fungi and parasites (Jenssen & Hancock, 2009). It is also able to promote skin integrity by regulating the generation of humoral components of the inflammatory and immune responses, including such cytokines as the tumor necrosis factor (TNF) alpha and interleukin (IL) 1beta, as well as the migration of Langerhans cells (Kimber et al., 2002). Moreover, lactoferrin enhances collagen gel contractile activity of fibroblasts, leading to skin wound healing (Takayama & Takezawa, 2006).