Belchiolina Beatriz Fonseca

A glance at Listeria and Salmonella cell invasion: Different strategies to promote host actin polymerization

The facultative intracellular bacterial pathogens Listeria monocytogenes and Salmonella enterica have evolved multiple strategies to invade a large panel of mammalian cells. These pathogens use the host cell actin system for invasion and became a paradigm for the study of host-pathogen interactions and bacterial adaptation to mammalian hosts. The key signaling component that these pathogens use to orchestrate actin remodeling is the Arp2/3 complex, which is related to polymerization of actin filaments. These bacterial pathogens are able to trigger distinct invasion mechanisms. On the one hand, L. monocytogenes invade a host cell in a way dependent on the specific interactions between bacterial and host cell proteins, which in turn activate the host cell actin polymerizing machinery that culminates with bacterial internalization. Also, Listeria escapes from the newly formed parasitophorous vacuole and moves among adjacent cells by triggering actin polymerization. On the other hand, Salmonella invades a host cell by delivering into the cytoplasm virulence factors which directly interact with host regulators of actin polymerization which leads to bacterial uptake. Moreover, Salmonella avoids vacuole lyses and modulates the early and late endosomal markers presented in the vacuole membrane. This mini-review focuses on the different pathways that L. monocytogenes and S. enterica activate to modulate the actin cytoskeleton in order to invade, to form the parasitophorous vacuole, and to migrate inside host cells.

Campylobacter sp in eggs from cloacal swab positive breeder hens

Campylobacter sp is a microaerophilic, thermotolerating Gram negative bacterium, known to be one of the main causes of food-borne human infections. Among the foods that carry these microorganisms, the chicken is outstanding. In Brazil, a large chicken exporting country, few researches are conducted about their prevalence in breeder hens and the transmission through eggs. The aim of this research was to verify the presence of Campylobacter sp in the shells and within the eggs from positive cloacal swab breeder hens. Microbiological analyses were made on cloacal swabs of 140 weighed breeder hens. The positive breeder hens were set aside and in a total of 244 of their eggs, Campylobacter sp was present in macerated shells and yolk contents during 7 weeks. Out of the 140 researched breeder hens, 25 (17.8%) were positive from cloacal swabs, however the eggs were not positive. The physiological characteristics of the birds, their eggs and Campylobacter sp favor the bacterium entering and surviving in the eggs, but in this study, no positive result was found in macerated shells or in the yolks, indicating that vertical transmission is probably an unusual event.

Transfer, viability and colonisation of Campylobacter jejuni in the chicken vitellus and in embryos

1. The objective of this study was to evaluate the ability of Campylobacter jejuni to penetrate and colonise eggs from specific-pathogen-free (SPF) and heavy breeder hens, and to determine its effects on the viability of SPF embryos. 2. We detected C. jejuni in 10% of breeder hens and 20% of SPF eggs, which demonstrates the ability of the bacteria to go through the pores of eggs and contaminate the vitellus after 3 h of contact. These results indicate that there is a risk of contamination under commercial production conditions, where, after oviposition, there is contact between the egg and organic material such as faeces and blood. 3. We observed that in 80% of SPF eggs analysed, C. jejuni survived the 21-d incubation period. This positive result suggests that this microorganism was also responsible for early embryonic mortality. 4. The ability of C. jejuni to penetrate the eggs in this study suggests that serious problems may occur under natural field conditions, which may cause significant problems for producers.

Microbiota of the cecum, ileum morphometry, pH of the crop and performance of broiler chickens supplemented with probiotics

It was studied, in this work, the effects of supplementation of probiotics on the performance, on the pH of crop content, on the morphometry of the ileum and on the number of enterobacteria in the cecum of the broilers. Out of the 120 studied birds, 60 belonged to the test group and 60 to the control group. At 1, 7, 12, 18, 23 and 28 days of age, the chickens and rations were weighed and mortality and morbidity were determined. Then, the birds were sacrificed and the pH of the crop content was measured, ileum fragments were collected for morphometric analysis and the enterobacteria in the cecal content were quantified. The mean pH was lower in the group that was given probiotics at 1, 7 and 18 days of age. There were no differences on ration consumption, weight, mortality and morbidity rates. The counts of enterobacteria were lower in the supplemented animals at the ages of 7, 18 and 28 days. The measure of villus of the ileum was higher for the group treated with probiotics at all ages, except for 1 day of age in comparison to the control group. This work proves that supplementation with probiotics reduces the pH of the crop content at the ages of 1, 7 and 18 days and it can contribute to the reduction of pathogenic bacteria on the first days of life by reducing the quantity of enterobacteria in the cecum. In addition, probiotics increase the height of villi in the ileum of the birds.

Characterization of the virulence, growth temperature and antibiotic resistance of the Campylobacter jejuni IAL 2383 strain isolated from humans

The objective of this study was to characterize the C. jejuni IAL2383 strain isolated from humans in Brazil. Transcripts for the racR, dnaJ and ciaB genes were found and flaA, plda and cadF genes were present in the genome and bacteria was sensitive to most of the important antimicrobials used to treat humans. C. jejuni IAL2383 is a good experimental model to analyze the interactions with cells.

Occurrence and characterization of Campylobacter spp.isolates in dogs, cats and children

Com o objetivo de melhorar o entendimento das infeccoes por Campylobacterspp. em caes, gatos e criancas no Brasil, foram avaliadas 160 amostras fecais de criancas e 120 swabs retais de pets (103 caes e 17 gatos). Do total das amostras das criancas, 6,87% foram positivas para Campylobacter spp. e em caes e gatos a positividade foi de 18,3%. Das 33 amostras positivas para Campylobacter spp., 57,6% foram identificadas como C. jejunie 33,4% foram identificadas como C. coli. Mais de 50% das amostras isoladas de pets foram resistentes a ceftiofur, sulphazotrim, norfloxacina e tetraciclina. Em criancas, a maioria das amostras foi resistente a amoxilina, cefazolina, ceftiofur, eritromicina e norfloxacina. De 19 isolados de C. jejuni, 11 isolados de criancas e cinco (5) de caes tinham dois (2) dos quatro (4) genes de virulencia flaA, pldA, cadFor ciaB. Associacao positiva entre a presenca de Campylobacter spp. e diarreia em caes e gatos foi observada em animais desverminados e com hemograma sugestivo de infeccao bacteriana. Tambem houve associacao positiva entre a presenca dos genes de virulencia e a ocorrencia de diarreia, e entre o uso de antibioticos e a positividade para Campylobacterspp. em suabes fecais de pets. Os dados desse trabalho indicam que cepas virulentas de Campylobacter spp. sao fatores de risco para diarreia em caes e a resistencia antimicrobiana e comum em isolados de caes

Effects of inverting the position of layers eggs during storage on hatchery performance parameters

Storing hatchable eggs is a common practice in commercial hatcheries. However, storage time may negative effects on several performance parameters. An experiment was carried out to evaluate inverting egg position during storage of eggs laid by young and old layer breeders. Fertile eggs of 32 and 58-week-old breeders were stored for seven, 14, and 21 days at 18oC ± 2oC and 80% ± 10% relative humidity (RU). The following parameters were evaluated: egg weight loss, hatchability and hatchling weight, and embryodiagnosis results. Eggs stored with the small end up lost less weight during storage compared with the control eggs. Storing eggs for 14 days with the small end up reduced early embryo mortality, improving hatchability. In addition, hatchling weight increased. These results show that the detrimental effects of long storage periods may be alleviated when eggs are stored with the small end up to 14 days of storage.

Identificação sorológica e relação filogenética de Salmonella spp. de origem suína

Salmonella spp. is an important zoonotic pathogen that can spread along the production chain of swines. The objective was to evaluate the incidence of Salmonella spp. in feces of swines in termination phase in the farm, in the pre-slaughter and environmental samples, identify the serotypes and establish a phylogenetic relationship among the isolates. Three collections were done in different batches of pigs housed in the termination pen and in the same animals after transport to the slaughterhouse totaling 90 plots and 9 environmental samples. The transport does not influenced the percentage of isolation of the microorganism (p>0.05). Of the total of 99 samples, 50 (50.5%) were identified as Salmonella spp., and was identified a variety of serovars: Agona (30%), Typhimurium (26%), Minnesota (24%), Infantis (18%) and Panama (2%). Dendrograms showed homology among isolates of different serovars grouped into clusters. The similarity was independent of the local of isolation, indicating the presence of several clones. The main sources of infection were cross-contamination between animals and environment and the consumption of contaminated feed. The diversity of strains and homology among the isolates indicates a common origin, demonstrating a need for monitoring of zoonotic bacterias and the deployment of more effective control measures for Salmonella spp. in swines.

Campylobacter spp. and Related Organisms in Poultry

Members of the Campylobacter genus are Gram-negative, microaerophilic, small bacilli with polar flagellation. Bacterial movement has a typical corkscrew characteristic. There are many species associated with different diseases. This chapter describes the taxonomy, genetic structure, and general characteristics of the Campylobacter genus focusing on thermophilic species and/or those that colonize the intestinal tract of birds.

Campylobacter jejuni in Poultry: A Commensal or a Pathogen?

Campylobacter has a long standing association with poultry and is the main cause of cases of human foodborne disease in the developed world, with most cases being linked back to the poultry reservoir, particularly chicken. Campylobacter is ideally suited to the poultry niche, and can grow at the increased body temperature of birds of 42 °C. Historically Campylobacter was referred to as a commensal of poultry, as it is found in the majority of birds reared for human consumption irrespective of the breed or rearing system used, even though there is experimental evidence from over 30 years ago that certain Campylobacter strains harm broiler chickens. More recently there is an increasing body of evidence, supporting this early work, which indicates that Campylobacter is not necessarily a commensal of poultry and under certain conditions the bacterium behaves more like a pathogen. Birds mount innate and adaptive immune responses to Campylobacter. Recent studies have highlighted the ability of Campylobacter to leave the gut and be found in other internal organs and muscle tissue. In addition, Campylobacter has been shown to have a negative effect on the health and welfare of the birds, Furthermore evidence of host adaptation and host-specific species leads us to believe that Campylobacter is more than just a commensal of chickens. Here we will review the role of Campylobacter, host adaption and commensalism within the poultry niche.