Multiresistant Salmonella enterica serovar 4,[5],12:i:- in Europe: a new pandemic strain?

A marked increase in the prevalence of S. enterica serovar 4,[5],12:i:- with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines (R-type ASSuT) has been noted in food-borne infections and in pigs/pig meat in several European countries in the last ten years. One hundred and sixteen strains of S. enterica serovar 4,[5],12:i:- from humans, pigs and pig meat isolated in England and Wales, France, Germany, Italy, Poland, Spain and the Netherlands were further subtyped by phage typing, pulsed-field gel electrophoresis and multilocus variable number tandem repeat analysis to investigate the genetic relationship among strains. PCR was performed to identify the fljB flagellar gene and the genes encoding resistance to ampicillin, streptomycin, sulphonamides and tetracyclines. Class 1 and 2 integrase genes were also sought. Results indicate that genetically related serovar 4,[5],12:i:- strains of definitive phage types DT193 and DT120 with ampicillin, streptomycin, sulphonamide and tetracycline resistance encoded by blaTEM, strA-strB, sul2 and tet(B) have emerged in several European countries, with pigs the likely reservoir of infection. Control measures are urgently needed to reduce spread of infection to humans via the food chain and thereby prevent the possible pandemic spread of serovar 4,[5],12:i:- of R-type ASSuT as occurred with S. Typhimurium DT104 during the 1990s.

Salmonella Enterica serovar Typhimurium Infection in Mouse Pregnancy

Salmonella are Gram-negative, intracellular food-borne pathogens that cause pregnancy complications. In pregnant mice, Salmonella enterica serovar Typhimurium (S.Tm) infection results in placental bacterial replication, inflammation, necrosis, and fetal loss by unknown mechanisms. Necroptosis, or programmed necrosis mediated by RIPK3 (receptor-interacting protein kinase 3), an inflammatory cell death pathway, is implicated in the pathogenesis of S.Tm in non-pregnant mice. This goal of this thesis was to investigate the role of necroptosis in the pathogenesis of S.Tm infection during mouse pregnancy. I hypothesized that elimination of the key necroptotic cell death protein RIPK3 would decrease placental inflammation and trophoblast cell death, and increase conceptus survival compared to controls. Mice expressing a functional Slc11a1 (encodes the natural resistance-associated macrophage protein 1, NRAMP1) gene with or without RIPK3 function (Ripk3-/-Slc11a1+/+ compared to Slc11a1+/+) were infected with 103 S.Tm by tail vein injection on gestational day (GD) 12. Mice were euthanized on GD 14 (48h post-infection) or GD 15 (72h post-infection) and implantation sites (IS) and maternal serum were harvested for analyses. In nearly all challenged mice (except one outlier), S.Tm were detected in most IS within a litter but there was limited immune cell infiltration, placental damage or cell death in Slc11a1 competent mice regardless of Ripk3 gene deletion. Maternal serum cytokine analyses confirmed lack of maternal immune responses to S.Tm infection. IS amongst the litter of a single dam (Ripk3-/-Slc11a1+/+ at 72h postinfection) displayed heavy but not universal placental S.Tm infection of decidual tissues and spongiotrophoblast, associated with elevated maternal serum pro-inflammatory cytokines. S.Tm infection of the fetal yolk sac (YS) was observed in 54.5% of IS from this dam. YS infection was confirmed in archival samples in mice expressing Ripk3 with intact Slc11a1 and in mice lacking functional Slc11a1. In Slc11a1 incompetent mice, S.Tm were detected in placental labyrinthine trophoblast. Based on the available data, this thesis suggests that Ripk3 and necroptosis have no significant roles in either promotion or prevention of progressive Salmonella infection during mouse pregnancy. It also provides pilot data that NRAMP1 controls placental localization and lethality due to YS infection.

Utilización de antimicrobianos en las infecciones odontogénicas en niños y adolescentes: análisis farmacocinético/farmacodinámico (PK/PD)

El objetivo de este estudio es evaluar la eficacia de los tratamientos más utilizados en infecciones odontogénicas en niños y adolescentes aplicando criterios farmacocinéticos/farmacodinámicos (PK/PD). Se han simulado las curvas de concentración plasmática libre-tiempo a partir de parámetros farmacocinéticos medios de amoxicilina, amoxicilina-ácido clavulánico, cefuroxima axetilo, espiramicina, clindamicina, azitromicina y metronidazol. Para los antibióticos con actividad dependiente del tiempo, se ha calculado el tiempo durante el cual las concentraciones permanecen por encima de la concentración inhibitoria mínima (CIM90) de los microorganismos (T>CIM). Para los antimicrobianos con actividad dependiente de la concentración, se ha calculado el cociente entre el área bajo la curva y la CIM90 (ABC/CIM90). Con amoxicilina-ácido clavulánico (80 mg/kg/día) se han obtenido índices de eficacia adecuados frente a los microorganismos estudiados (T > CIM > 40%), excepto paraVeillonella spp. Clindamicina (40 mg/kg/día) también ha presentado índices PK/PD adecuados frente a la mayoría de los patógenos, excepto Lactobacillus, Actinobacillus actinomycetemcomitans, Peptostreptococcus resistente a penicilina y Eikenella corrodens. Con dosis altas de amoxicilina los resultados no han sido satisfactorios frente a varias especies bacterianas. Con azitromicina y metronidazol no se han alcanzado valores adecuados frente a la mayoría de patógenos (ABC/CIM90 < 25). En conclusión, el tratamiento empírico más adecuado en infecciones odontogénicas en niños y adolescentes es amoxicilina-ácido clavulánico en altas dosis de amoxicilina, aunque se puede utilizar como alternativa clindamicina. Sería conveniente confirmar estos resultados mediante ensayos clínicos, para cuyo diseño y evaluación podría ser de gran utilidad la aplicación de estudios PK/PD.

Enteropatógenos y antibióticos

La gastroenteritis infecciosa continúa siendo un problema de salud pública. La etiología bacteriana es la responsable de la mayoría de los casos graves. En nuestro país, Campylobacter y Salmonella son los géneros bacterianos más prevalentes, mientras que Yersinia y Shigella son mucho menos frecuentes. La mayoría de los casos suelen ser autolimitados y, en general, el tratamiento antibiótico no está indicado, salvo en pacientes con factores de riesgo de infección grave y en shigelosis. Ciprofloxacino, cefalosporinas de tercera generación, azitromicina, ampicilina, cotrimoxazol y doxiciclina son los fármacos más recomendados. El patrón de sensibilidad de las diferentes bacterias determina la elección del tratamiento antibiótico más adecuado. El objetivo de esta revisión es analizar la situación, las novedades y la evolución de la resistencia y la multirresistencia en estos 4 enteropatógenos.

Resistência antimicrobiana em salmonella spp. isoladas de aviários de frangos de corte: dados parciais.

2016

An Isoflavone From Dipteryx Alata Vogel Is Active Against The In Vitro Neuromuscular Paralysis Of Bothrops Jararacussu Snake Venom And Bothropstoxin I, And Prevents Venom-induced Myonecrosis.

Snakebite is a neglected disease and serious health problem in Brazil, with most bites being caused by snakes of the genus Bothrops. Although serum therapy is the primary treatment for systemic envenomation, it is generally ineffective in neutralizing the local effects of these venoms. In this work, we examined the ability of 7,8,3'-trihydroxy-4'-methoxyisoflavone (TM), an isoflavone from Dipteryx alata, to neutralize the neurotoxicity (in mouse phrenic nerve-diaphragm preparations) and myotoxicity (assessed by light microscopy) of Bothrops jararacussu snake venom in vitro. The toxicity of TM was assessed using the Salmonella microsome assay (Ames test). Incubation with TM alone (200 μg/mL) did not alter the muscle twitch tension whereas incubation with venom (40 μg/mL) caused irreversible paralysis. Preincubation of TM (200 μg/mL) with venom attenuated the venom-induced neuromuscular blockade by 84% ± 5% (mean ± SEM; n = 4). The neuromuscular blockade caused by bothropstoxin-I (BthTX-I), the major myotoxic PLA2 of this venom, was also attenuated by TM. Histological analysis of diaphragm muscle incubated with TM showed that most fibers were preserved (only 9.2% ± 1.7% were damaged; n = 4) compared to venom alone (50.3% ± 5.4% of fibers damaged; n = 3), and preincubation of TM with venom significantly attenuated the venom-induced damage (only 17% ± 3.4% of fibers damaged; n = 3; p < 0.05 compared to venom alone). TM showed no mutagenicity in the Ames test using Salmonella strains TA98 and TA97a with (+S9) and without (-S9) metabolic activation. These findings indicate that TM is a potentially useful compound for antagonizing the neuromuscular effects (neurotoxicity and myotoxicity) of B. jararacussu venom.

Influence Of The Major Nitrite Transporter Nirc On The Virulence Of A Swollen Head Syndrome Avian Pathogenic E. Coli (apec) Strain.

Avian Pathogenic Escherichia coli (APEC) strains are extra-intestinal E. coli that infect poultry and cause diseases. Nitrite is a central branch-point in bacterial nitrogen metabolism and is used as a cytotoxin by macrophages. Unlike nitric oxide (NO), nitrite cannot diffuse across bacterial membrane cells. The NirC protein acts as a specific channel to facilitate the transport of nitrite into Salmonella and E. coli cells for nitrogen metabolism and cytoplasmic detoxification. NirC is also required for the pathogenicity of Salmonella by downregulating the production of NO by the host macrophages. Based on an in vitro microarray that revealed the overexpression of the nirC gene in APEC strain SCI-07, we constructed a nirC-deficient SCI-07 strain (ΔnirC) and evaluated its virulence potential using in vivo and in vitro assays. The final cumulative mortalities caused by mutant and wild-type (WT) were similar; while the ΔnirC caused a gradual increase in the mortality rate during the seven days recorded, the WT caused mortality up to 24h post-infection (hpi). Counts of the ΔnirC cells in the spleen, lung and liver were higher than those of the WT after 48 hpi but similar at 24 hpi. Although similar number of ΔnirC and WT cells was observed in macrophages at 3 hpi, there was higher number of ΔnirC cells at 16 hpi. The cell adhesion ability of the ΔnirC strain was about half the WT level in the presence and absence of alpha-D-mannopyranoside. These results indicate that the nirC gene influences the pathogenicity of SCI-07 strain.

Estabilidade oxidativa e microbiológica em carne de galinha mecanicamente separada e adicionada de antioxidantes durante período de armazenamento a -18 &deg;C

Com o objetivo de acompanhar a estabilidade físico-química e microbiológica da carne mecanicamente separada (CMS) de diferentes origens e estocada durante 99 dias a -18 &deg;C, foi realizada prévia mistura de conservante (nitrito de sódio) e antioxidante (eritorbato de sódio) em CMS obtida de duas linhagens de aves: galinhas matrizes de corte e galinhas poedeiras comerciais brancas. Na CMS de cada linhagem foram realizados três diferentes tratamentos: 1) controle (sem aditivos); 2) adição de 150 ppm de nitrito; e 3) adição de 150 ppm de nitrito e 500 ppm de eritorbato. Os resultados encontrados demonstraram que a adição de nitrito isoladamente não impediu a oxidação lipídica, avaliada através do índice de TBARS, nem a alteração na cor, avaliada em colorímetro. Por outro lado, a adição de nitrito juntamente com eritorbato foi efetiva na redução dos problemas de oxidação lipídica na CMS de galinhas matrizes, e em menor grau, na CMS de poedeiras. A adição de nitrito e eritorbato na CMS também melhorou a preservação da cor vermelha desejável (a*) ao longo do tempo. A avaliação da estabilidade microbiológica da CMS, realizada no primeiro e último dia de estocagem congelada, para microrganismos mesófilos, Escherichia coli, Staphylococcus aureus, Clostridium perfringens e Pseudomonas spp., e quinzenalmente para microrganismos psicrotróficos, indicou que não houve uma variação significativa nas contagens em função do tratamento utilizado (diferentes aditivos adicionados). Não foi detectada Salmonella spp. em nenhuma das amostras analisadas. Em função da melhoria da estabilidade oxidativa, recomenda-se a adição de nitrito (150 ppm) e eritorbato (500 ppm) em CMS de galinhas matrizes a ser estocada congelada por um período prolongado.

Áreas de vulnerabilidade para co-infecção HIV-aids/TB em Ribeirão Preto, SP

OBJETIVO: Identificar áreas de vulnerabilidade para os casos novos de co-infecção HIV/tuberculose (TB). MÉTODOS: Estudo descritivo ecológico realizado por meio do georreferenciamento dos casos novos de HIV/TB notificados em Ribeirão Preto, SP, em 2006. Os dados foram obtidos do sistema de informação estadual paulista de notificação de TB. Os casos novos de co-infecção HIV/TB foram analisados conforme características sociodemográficas e clínicas e, posteriormente, georreferenciados na base cartográfica do município segundo endereço residencial. Os setores do município foram categorizados em três níveis socioeconômicos: inferior, intermediário e superior, com base na análise de componentes principais das variáveis do censo demográfico de 2000 (renda, instrução e percentagem de domicílios com cinco ou mais moradores). Foi calculada a incidência da co-infecção HIV/TB para cada nível socioeconômico. RESULTADOS: A co-infecção HIV/TB acometeu mais adultos do sexo masculino em idade economicamente ativa e a forma pulmonar da TB foi a mais comum. A distribuição espacial mostrou que as incidências nas áreas com níveis socioeconômicos intermediários e inferiores (8,3 e 11,5 casos por 100 mil habitantes, respectivamente) foram superiores àquela (4,8 casos por 100 mil habitantes) de nível socioeconômico superior. CONCLUSÕES: A taxa de incidência de co-infecção HIV/TB analisada por níveis socioeconômicos mostrou padraÞo espacial de distribuiçaÞo não homogêneo e apresentou valores mais altos em áreas de maior vulnerabilidade social. O estudo diagnosticou aìreas geograìficas prioritaìrias para o controle da co-infecção e a tecnologia do sistema de informação geográfica pode ser empregada no planejamento das ações em saúde pelos gestores municipais.

Microbiological quality of hamburgers sold in the streets of Cuiabá - MT, Brazil and vendor hygiene-awareness

This study evaluated the microbiological quality of hamburgers and the microbe community on the hands of vendors in Cuiabá, Mato Grosso, Brazil, in relation to vendors´ awareness as to what constitute acceptable food-handling practices as part of a broad-spectrum research programme on street foods in Brazil . Sale of the hamburger known as the 'baguncinha' is common and widespread in urban Cuiabá, Mato Grosso, Brazil. Food inspectors encounter various difficulties in carrying out inspections. One hundred and five hamburgers samples were evaluated using conventional methods including tests for facultative aerobic and/or anaerobic mesophytic bacteria, coliform counts at 45 °C, the coagulase test for Staphylococcus, Gram-staining for the presence of Bacillus cereus, Clostridium sulphite reductase and Salmonella spp. The hamburgers were categorized as unsuitable for human consumption in 31.4% of samples, with those testing positive for coliforms and Staphylococcus at unacceptably high levels by Brazilian standards. High levels of microbiological contamination were detected on the hands of the food handlers and mesophytic bacterial counts reached 1.8 × 10(4) CFU/hand. Interviews were carried out by means of questionnaires to evaluate levels of awareness as to acceptable food handling practices and it was found that 80,1% of vendors had never participated in any kind of training.

Etiologic diagnosis of bovine infectious abortion by PCR

Infectious abortion is a significant cause of reproductive failure and economic losses in cattle. The goal of this study was to detect nucleic acids of several infectious agents known to cause abortion including Arcanobacterium pyogenes, Bovine Herpesvirus 1, Brucella abortus, Campylobacter fetus subsp. venerealis, Chlamydophila abortus, Leptospira sp., Listeria monocytogenes, Salmonella sp., Mycoplasma bovis, Mycoplasma bovigenitalium, Neospora caninum, and Tritrichomonas foetus. Tissue homogenates from 42 fetuses and paraffin-embedded tissues from 28 fetuses and 14 placentas/endometrium were included in this study. Brucella abortus was detected in 14.2% (12/84) of the samples. Salmonella sp. DNA was amplified from 2 fetuses, and there was one positive for Neospora caninum, and another for Listeria monocytogenes. This PCR-based approach resulted in identification of the etiology in 19% of samples, or 20% if considered fetal tissues only.

Serosurvey of selected avian pathogens in brazilian commercial Rheas (Rhea americana) and Ostriches (Struthio camelus)

Ratite farming of has expanded worldwide. Due to the intensive farming methods used by ratite producers, preventive medicine practices should be established. In this context, the surveillance and control of some avian pathogens are essential for the success of the ratite industry; however, little is known on the health status of ratites in Brazil. Therefore, the prevalence of antibodies against Newcastle Disease virus, Chlamydophila psittaci, Mycoplasma gallisepticum, Mycoplasma synoviae, and Salmonella Pullorum were evaluated in 100 serum samples collected from commercial ostriches and in 80 serum samples from commercial rheas reared in Brazil. All sampled animals were clinically healthy. The results showed that all ostriches and rheas were serologically negative to Newcastle disease virus, Chlamydophila psittaci, Mycoplasma gallisepticum, and Mycoplasma synoviae. Positive antibody responses against Salmonella Pullorum antigen were not detected in ostrich sera, but were detected in two rhea serum samples. These results can be considered as a warning as to the presence of Salmonella spp. in ratite farms. Therefore, the implementation of good health management and surveillance programs in ratite farms may contribute to improve not only animal production, but also public health conditions.

Structure-Function Analysis of the HrpB2-HrcU Interaction in the Xanthomonas citri Type III Secretion System

Bacterial type III secretion systems deliver protein virulence factors to host cells. Here we characterize the interaction between HrpB2, a small protein secreted by the Xanthomonas citri subsp. citri type III secretion system, and the cytosolic domain of the inner membrane protein HrcU, a paralog of the flagellar protein FlhB. We show that a recombinant fragment corresponding to the C-terminal cytosolic domain of HrcU produced in E. coli suffers cleavage within a conserved Asn264-Pro265-Thr266-His267 (NPTH) sequence. A recombinant HrcU cytosolic domain with N264A, P265A, T266A mutations at the cleavage site (HrcU(AAAH)) was not cleaved and interacted with HrpB2. Furthermore, a polypeptide corresponding to the sequence following the NPTH cleavage site also interacted with HrpB2 indicating that the site for interaction is located after the NPTH site. Non-polar deletion mutants of the hrcU and hrpB2 genes resulted in a total loss of pathogenicity in susceptible citrus plants and disease symptoms could be recovered by expression of HrpB2 and HrcU from extrachromossomal plasmids. Complementation of the Delta hrcU mutant with HrcU(AAAH) produced canker lesions similar to those observed when complemented with wild-type HrcU. HrpB2 secretion however, was significantly reduced in the Delta hrcU mutant complemented with HrcU(AAAH), suggesting that an intact and cleavable NPTH site in HrcU is necessary for total functionally of T3SS in X. citri subsp. citri. Complementation of the Delta hrpB2 X. citri subsp. citri strain with a series of hrpB2 gene mutants revealed that the highly conserved HrpB2 C-terminus is essential for T3SS-dependent development of citrus canker symptoms in planta.

Etiology of childhood diarrhea in the northeast of Brazil: significant emergent diarrheal pathogens

In a study conducted in Joao Pessoa, northeast of Brazil, 2344 Escherichia coli isolated from 290 infants with diarrhea and 290 healthy matched controls were analyzed for virulence traits. Enteroaggregative E. coli (EAEC) was the most prevalent pathogen associated to acute diarrhea. Based on the results of colony blot hybridization, serotyping, and HEp-2 cell adherence assays, strains were separated in categories as typical enteropathogenic E. coli (EPEC) (1.7%), atypical EPEC (a-EPEC) (9.3%), EAEC (25%), enterotoxigenic E. coli (10%), and enteroinvasive E. coli (EIEC) (1.4%). No enterohemorrhagic E. coli strains were isolated. Other enteropathogens were found, including Salmonella (7.9%), Shigella spp. (4.1%), thermophilic Campylobacter spp. (2.4%), Giardia lamblia (9.3%), and Entamoeba histolytica (5.8%). All enteropathogens were associated with diarrhea (P < 0.01). However, the association was lower for EPEC and EIEC (P < 0.03). Different pathogens associated with diarrhea may have been changing in Brazil where EAEC and a-EPEC seem to be the most prevalent pathogens among them. (C) 2010 Elsevier Inc. All rights reserved.

A recombinant vaccine based on domain II of Plasmodium vivax Apical Membrane Antigen 1 induces high antibody titres in mice

The Apical Membrane Antigen 1 (AMA-1) is considered a promising candidate for development of a malaria vaccine against asexual stages of Plasmodium. We recently identified domain II (DII) of Plasmodium vivax AMA-1 (PvAMA-1) as a highly immunogenic region recognised by IgG antibodies present in many individuals during patent infection with P. vivax. The present study was designed to evaluate the immunogenic properties of a bacterial recombinant protein containing PvAMA-1 DII. To accomplish this, the recombinant protein was administered to mice in the presence of each of the following six adjuvants: Complete/Incomplete Freund`s Adjuvant (CFA/IFA), aluminium hydroxide (Alum), Quil A, QS21 saponin, CpG-ODN 1826 and TiterMax. We found that recombinant DII was highly immunogenic in BALB/c mice when administered in the presence of any of the tested adjuvants. Importantly, we show that DII-specific antibodies recognised the native AMA-1 protein expressed on the surface of P. vivax merozoites isolated from the blood of infected patients. These results demonstrate that a recombinant protein containing PvAMA-1 DII is immunogenic when administered in different adjuvant formulations, and indicate that this region of the AMA-1 protein should continue to be evaluated as part of a subunit vaccine against vivax malaria. (C) 2010 Elsevier Ltd. All rights reserved.