Salmonella enterica Serovars Dublin and Enteritidis Comparative Proteomics Reveals Differential Expression of Proteins Involved in Stress Resistance, Virulence, and Anaerobic Metabolism.

The Enteritidis and Dublin serovars of Salmonella enterica are phylogenetically closely related yet differ significantly in host range and virulence. S Enteritidis is a broad-host-range serovar that commonly causes self-limited gastroenteritis in humans, whereas S Dublin is a cattle-adapted serovar that can infect humans, often resulting in invasive extraintestinal disease. The mechanism underlying the higher invasiveness of S Dublin remains undetermined. In this work, we quantitatively compared the proteomes of clinical isolates of each serovar grown under gut-mimicking conditions. Compared to S Enteritidis, the S Dublin proteome was enriched in proteins linked to response to several stress conditions, such as those encountered during host infection, as well as to virulence. The S Enteritidis proteome contained several proteins related to central anaerobic metabolism pathways that were undetected in S Dublin. In contrast to what has been observed in other extraintestinal serovars, most of the coding genes for these pathways are not degraded in S Dublin. Thus, we provide evidence that S Dublin metabolic functions may be much more affected than previously reported based on genomic studies. Single and double null mutants in stress response proteins Dps, YciF, and YgaU demonstrate their relevance to S Dublin invasiveness in a murine model of invasive salmonellosis. All in all, this work provides a basis for understanding interserovar differences in invasiveness and niche adaptation, underscoring the relevance of using proteomic approaches to complement genomic studies.

A rural worker infected with a bovine-prevalent genotype of Campylobacter fetus subsp. fetus supports zoonotic transmission and inconsistency of MLST and whole-genome typing.

Whole-genome characterisation in clinical microbiology enables to detect trends in infection dynamics and disease transmission. Here, we report a case of bacteraemia due to Campylobacter fetus subsp. fetus in a rural worker under cancer treatment that was diagnosed with cellulitis; the patient was treated with antibiotics and recovered. The routine typing methods were not able to identify the microorganism causing the infection, so it was further analysed by molecular methods and whole-genome sequencing. The multi-locus sequence typing (MLST) revealed the presence of the bovine-associated ST-4 genotype. Whole-genome comparisons with other C. fetus strains revealed an inconsistent phylogenetic position based on the core genome, discordant with previous ST-4 strains. To the best of our knowledge, this is the first C. fetus subsp. fetus carrying the ST-4 isolated from humans and represents a probable case of zoonotic transmission from cattle.

Prevalence of Salmonella enterica in poultry and eggs in Uruguay during an epidemic due to Salmonella enterica serovar Enteritidis.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is frequently associated with food-borne disease worldwide. Poultry-derived products are a major source. An epidemic of human infection with S. Enteritidis occurred in Uruguay, and to evaluate the extent of poultry contamination, we conducted a nationwide survey over 2 years that included the analysis of sera from 5,751 birds and 12,400 eggs. Serological evidence of infection with Salmonella group O:9 was found in 24.4% of the birds. All positive sera were retested with a gm flagellum-based enzyme-linked immunosorbent assay, and based on these results, the national prevalence of S. Enteritidis infection was estimated to be 6.3%. Salmonellae were recovered from 58 of 620 pools made up of 20 eggs each, demonstrating a prevalence of at least 1 in every 214 eggs. Surprisingly, the majority of the isolates were not S. Enteritidis. Thirty-nine isolates were typed as S. Derby, 9 as S. Gallinarum, 8 as S. Enteritidis, and 2 as S. Panama. Despite the highest prevalence in eggs, S. Derby was not isolated from humans in the period of analysis, suggesting a low capacity to infect humans. Microarray-based comparative genomic hybridization analysis of S. Derby and S. Enteritidis revealed more than 350 genetic differences. S. Derby lacked pathogenicity islands 13 and 14, the fimbrial lpf operon, and other regions encoding metabolic functions. Several of these regions are present not only in serovar Enteritidis but also in all sequenced strains of S. Typhimurium, suggesting that these regions might be related to the capacity of Salmonella to cause food-borne disease.

An attenuated Salmonella Enteritidis strain derivative of the main genotype circulating in Uruguay is an effective vaccine for chickens.

We have recently reported that Salmonella enterica serovar Enteritidis (S. Enteritidis) strains circulating in Uruguay, are unevenly distributed among different genetic subtypes, with a predominant genotype that is a common contaminant of poultry-derived food and that accounts for the vast majority of human cases of food-borne disease. Herein, we describe the construction of a genetically-defined aroC derivative (LVR02) of a local strain of S. Enteritidis belonging to the major genetic type. We demonstrated the attenuation and the immunogenicity of that strain in a mouse model, and evaluated it as a vaccine for commercial layer chickens. LVR02 proved to be stable, attenuated, innocuous, immunogenic and to induce protective immunity against a S. Enteritidis challenge when used for oral vaccination. A single oral dose of LVR02 administered to newly hatched chickens induced protection against oral challenge with the parental virulent strain, preventing systemic and persistent intestinal infection and significantly reducing the shedding of the challenge strain in birds' feces. A second vaccine dose at 15 days post-hatching boosted the immunogenicity of the vaccine, and strengthened the protection achieved with a single dose. This strain may represent the basis of a live vaccine to be included in national control programs to reduce circulation of this pathogen in the country.

Intranasal immunization with a colloid-formulated bacterial extract induces an acute inflammatory response in the lungs and elicits specific immune responses.

Nonspecific stimulation of lung defenses by repeated oral administration of immunomodulators, such as bacterial extracts, has shown potential for the prevention of respiratory tract infections. Here, we show that intranasal (i.n.) immunization with a bacterial extract formulated as a colloid induces an acute inflammatory response in the lungs characterized by increased production of CCL and CXCL chemokines and a major influx of dendritic cells (DCs) and neutrophils, with a higher proportion of DCs showing an activated phenotype (high CD80/CD86 expression). Cytokine levels measured in bronchoalveolar-lavage samples showed a small increase in the production of tumor necrosis factor alpha and similar levels of the other cytokines measured (interleukin 10 [IL-10], IL-12, and gamma interferon [IFN-gamma]) in immunized mice compared with control mice. However, the recall response of primed animals after antigenic challenge induced increased expression of IL-12 and IFN-gamma mRNAs in lung homogenates. Overall, all these effects were not due to the lipopolysaccharide content in the bacterial extract. Furthermore, we found that three i.n. doses administered 2 to 3 weeks apart were enough to elicit long-lasting specific serum immunoglobulin G (IgG) and secretory IgA antibody responses. Assessment of IgG subclasses showed a balanced pattern of IgG1-IgG2a responses. The serum total IgE concentrations were also elevated in immunized mice 2 weeks after the third dose, but they significantly decreased soon afterwards. Our results suggest that simple formulations of bacterial extracts administered i.n. are highly immunogenic, eliciting local and systemic immune responses, and may serve as the basis for cost-effective immunotherapies for the prevention and treatment of respiratory infections.

Efecto del Lactobacillus casei administrado en el suero de rehidratación oral, en el tratamiento de la enfermedad diarreica aguda / Efficacy of Lactobacillus GG in oral rehidratation solution

El probiótico Lactobacillus GG es efectivo en promover una recuperación rápida de la diarrea aguda infantil producida por rotavirus. Hay poca información, sobre el rol de este agente en el efecto sobre la diarrea producida por otros gérmenes, tampoco hay evidencia de su eficacia administrada en la sal de hidratación oral para pscientes con diarrea de diversas causa. Método: Niños de 1 mes a 3 años de edad con enfermedad diarreica aguda fueron enrolados en una investigación doble ciego. Pacientes fueron randomizados y colocados en al grupo A recibiendo sal de hidratación y placebo, y en el grupo recibiendo, el mismo con el agragado de una preparación viva de Lactobacuillus GG. Luego de la hidratación en las 4 ó 6 horas se les ofreció su dieta habitual. Resultados: enrolamos 97 pacientes 52 del grupo A y 45 del grupo B. Duración de la diarrea luego del enrolamiento fue 7 días para el grupo A y 4 días para el grupo B (p<0.005).Para los niños rotavirus positivos la diarrea duró 6 días para el grupo A y 3 días para el grupo B (p<0.005).La diarrea duró más de 10 días, 5 para el grupo A y 1 para el grupo B. Conclusión: Administrar sal de hidratación oral conteniendo Lactobacillus GG a niños con enfermedad diarreica aguda es segura y resulta en duración menor de esta y tiene menos chance de pasar a curso prolongado. (AU)

Enfermedad de kikuchi-fujimoto: una entidad a considerar en el diagnóstico diferencial de las adenopatías cervicales. A propósito de tres casos / Kikuchi-Fujimoto disease: an entity to consider in differential diagnosis of the cervical adenopathy. Regard of three cases

La enfermedad de Kikuchi-Fujimoto es una rara entidad de causa desconocida que cursa con adenopatías cervicales persistentes que no responde a antibióticos ni antiinflamatorios. Aunque generalmente es benigna, ha sido confundida con linfomas malignos; por tanto, otorrinolaringólogos y patólogos deben de conocer esta enfermedad. Presentamos tres casos que han ocurrido recientemente en nuestro hospital (AU)

Introduction of thiol-reactive structures on to soluble and insoluble proteins.

When proteins containing disulphide groups were oxidized with magnesium monoperoxyphthalate at acidic pH, they acquired the property of binding thiol compounds. This was the case with the insoluble protein keratin, chosen for having a large number of disulphide bridges, and with soluble ones like BSA and immunoglobulins. The potential applications of some of these modified proteins for the preparation of soluble bioconjugates have been explored. As a particular example of an application, the immobilization of activated IgG on to solid phases might provide a new way for preparing immunoadsorbents.

Influence of human wet cerumen on the growth of common and pathogenic bacteria of the ear.

The available data on the effect of human wet cerumen on bacterial growth are not conclusive. Nevertheless it is widely accepted that cerumen has a bactericidal effect. In this study the activity of human wet cerumen on bacterial growth was assessed by applying cerumen suspensions to bacterial cultures. Bacterial counts were performed before and after application of cerumen suspensions. A total of 383 assays was carried out with 73 pools of cerumen that were tested against cultures of Staphylococcus aureus, Staphylococcus epidermidis, Corynebacterium spp., Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Serratia marcescens. An increase in growth occurred much more frequently than a decrease in growth in almost every microrganism tested, with the mean increase percentage being much higher than the mean decrease percentage, except in the case of S. aureus. The largest average growth increase was obtained with E. coli. The largest average decrease in bacterial growth was recorded with S. marcescens. Our study does not support the conception of a decrease in bacterial growth produced by humen wet cerumen. In vitro, the most observable effect was in fact an increase in microbial growth.

Study of common aerobic flora of human cerumen.

Cerumen is the product of the secretion of the sebaceous, ceruminous or apocrine glands together with cells exfoliated from the cornified stratum of the epithelium of the external auditory canal (EAC). In the present study we identified and quantified common flora of human cerumen. The mean count obtained was 10(6) microorganisms per ml of cerumen suspension. In 24 pools of cerumen (33.3 per cent) the isolates were monomicrobial, Staphylococcus epidermidis (12), Corynebacterium spp (10), Staphylococcus aureus (1) and Streptococcus saprophyticum (1). In 48 pools (66.6 per cent) we found polymicrobial isolates. The most commonly isolated bacteria in these polymicrobial isolates were S. epidermidis (35) and Corynebacterium spp. (43). It is noteworthy that there were isolates of Candida albicans in three cases; in one case of Pseudomonas stutzeri, in one case of Pseudomonas aeruginosa, and, on seven occasions, of S. aureus. The organisms isolated as common bacterial components of human cerumen in our experience were similar to those found by other authors. However, the mean count was much higher. This could be related to climatic conditions and to the length of time the cerumen had remained in the external auditory canal.

Etiology and therapy of chronic suppurative otitis.

Infectious diseases of the ear are important in adults due to their incidence and relapses. We carried out a study of aerobic microorganisms on 251 otic exudates from patients diagnosed as having chronic suppurative otitis media without cholesteatoma (119), chronic suppurative otitis media with cholesteatoma (85) and chronic external otitis (47). The microorganisms predominantly isolated were, Pseudomonas aeruginosa, Staphylococcus aureus and other Enterobacteriaceae. 86% of isolates were monomicrobial and 14% of isolates were polymicrobial. In these latter the predominantly isolated microorganisms were also P. aeruginosa, S. aureus, Corynebacterium spp. and Proteus mirabilis. P. aeruginosa was the most commonly isolated and showed the highest percentages of resistance against antimicrobial agents tested. P. aeruginosa was most susceptible to ciprofloxacin and imipenem, but much less susceptible to cefotaxime, moxalactam and trimethoprim-sulfamethoxazole. S. aureus was highly sensitive to amoxicillin/clavulanate, trimethoprim-sulfamethoxazole, rifampin and teichoplanin. 100% of the isolates were resistant to penicillin G and ampicillin.

Acyclovir in the treatment of laryngeal papillomatosis.

We report the results obtained in a study of 3 young patients with laryngeal papillomatosis, who were treated with acyclovir after tumor excision using forceps was performed under microlaryngoscopy. No recurrence of the papillomatosis occurred between 18 and 42 months post-therapy. Laryngeal papillomatosis is the most common proliferative laryngeal lesion in children. Different non-surgical therapies have been used to prevent its recurrence but with poor results. Acyclovir is a drug with proved efficacy in DNA viral diseases. Since papillomata of the larynx is most likely a viral disease which is imputed to have a DNA virus etiology, acyclovir may be effective to control it.