RESUMO
Disintegrins are low molecular weight cysteine-rich proteins (4-14 kDa) that are isolated mainly from viperid snake venom. Due to their potential as lead compounds for binding and blocking integrin receptors, snake venom disintegrins have become one of the most studied venom protein families. The aim of this study was to obtain disintegrins from C. totonacus venom and evaluate their capability to bind and block integrin receptors. The C. totonacus disintegrin fraction (totonacin) represents two disintegrin isoforms obtained from C. totonacus venom. These disintegrins showed extracellular-matrix (ECM) protein adhesion and migration inhibitory effects on MDA-MB-231 and HMEC-1 cells. Totonacin (3 µM) inhibited MDA-MB-231 cell adhesion to the ECM proteins, fibronectin, vitronectin, and laminin by 31.2, 44.0, and 32.1, respectively. Adhesion inhibition to fibronectin, vitronectin, and laminin observed on HMEC-1 cells was 42.8, 60.8, and 51%, respectively. In addition, totonacin (3 µM) significantly inhibited MDA-MB-231 and HMEC-1 cell migration (41.4 and 48.3%, respectively). Totonacin showed more potent cell adhesion inhibitory activity toward vitronectin in both cell lines. These results suggest a major affinity of totonacin toward αVß3, α8ß1, αVß5, αVß1, and αIIbß3 integrins. In addition, the inhibitory effect observed on MDA-MB-231 and HMEC-1 cell migration reinforces the evidence of an interaction between these disintegrins and αVß3 integrin, which plays a key role in migration and angiogenesis.
Assuntos
Venenos de Crotalídeos/química , Desintegrinas/farmacologia , Proteínas de Répteis/farmacologia , Animais , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Crotalus , Desintegrinas/isolamento & purificação , Humanos , Proteínas de Répteis/isolamento & purificação , Cicatrização/efeitos dos fármacosRESUMO
The objective of this study was to determine the serotype distribution and antibiotic resistance of invasive pneumococcal disease (IPD) strains in children from Lima, Peru, before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7), which was introduced in the national immunisation program on 2009. We conducted a prospective, multicentre, passive surveillance IPD study during 2006-2008 and 2009-2011, before and right after the introduction of PCV7 in Peru. The study was performed in 11 hospitals and five private laboratories in Lima, Peru, in patients <18 years old, with sterile site cultures yielding Streptococcus pneumoniae. In total 159 S. pneumoniae isolates were recovered. There was a decrease in the incidence of IPD in children <2 years old after the introduction of PCV7 (18.4/100 000 vs. 5.1/100 000, P = 0.004). Meningitis cases decreased significantly in the second period (P = 0.036) as well as the overall case fatality rate (P = 0.025), including a decreased case fatality rate of pneumonia (16.3% to 0%, P = 0.04). PCV7 serotypes showed a downward trend. Vaccine-preventable serotypes caused 78.9% of IPD cases, mainly 14, 6B, 5, 19F and 23F. A non-significant increase in erythromycin resistance was reported. Our findings suggest that the introduction of PCV7 led to a significant decrease of IPD in children under 2 years old and in the overall case fatality rate.
Assuntos
Farmacorresistência Bacteriana , Vacina Pneumocócica Conjugada Heptavalente/uso terapêutico , Infecções Pneumocócicas/epidemiologia , Streptococcus pneumoniae/efeitos dos fármacos , Adolescente , Fatores Etários , Criança , Pré-Escolar , Monitoramento Epidemiológico , Feminino , Humanos , Incidência , Lactente , Masculino , Peru/epidemiologia , Infecções Pneumocócicas/prevenção & controle , Estudos Prospectivos , Sorogrupo , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/imunologiaRESUMO
PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. OBJECTIVE: Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. METHODS AND RESULTS: The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpfO113. E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 108 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. CONCLUSIONS: These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment.
Assuntos
Aderência Bacteriana/fisiologia , Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli Shiga Toxigênica/fisiologia , Animais , Antibacterianos/farmacologia , Biofilmes , Bovinos , Chlorocebus aethiops , Farmacorresistência Bacteriana , Infecções por Escherichia coli/microbiologia , Escherichia coli O157 , Feminino , Regulação Bacteriana da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Escherichia coli Shiga Toxigênica/genética , Células Vero , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
OBJECTIVES: Lactoferrin (LF) is a breast milk glycoprotein with protective effects against neonatal infections, mainly in premature and low-birth-weight (LBW) neonates. The aims of this study were to determine LF concentration in breast milk of mothers of LBW infants during the first 2 months postpartum, and to identify the factors associated with LF concentration. STUDY DESIGN: Prospective study conducted as a part of an ongoing clinical trial in three Neonatal Units in Peru. We included 346 mothers of neonates with a birth weight <2000 g. We measured LF concentration in four stages of lactation using a commercial enzyme-linked immunosorbent assay kit. Multivariate analysis was performed to assess the association between maternal and neonatal factors, and LF concentration. RESULTS: We collected 695 milk samples. LF mean concentration±standard deviation was 14.92±7.96 mg ml-1 in colostrum (n=277), 10.73±5.67 in transitional milk (n=55), 10.34±6.27 at 1 month (n=259) and 8.52±6.47 at 2 months (n=104). There was a significant difference in LF concentration between different stages of lactation (P<0.001). Mothers with higher LF concentration in colostrum had higher values in the following 2 months. High maternal income and multiple gestation were significantly associated with higher LF levels; in contrast, maternal peripartum infections and male neonatal gender were associated with lower LF levels. CONCLUSIONS: LF concentration in breast milk of mothers of LBW infants was high and remained elevated even at 1 and 2 months postpartum. LF concentration in colostrum was higher in mothers with higher income and multiple pregnancies, and lower in mothers with peripartum infections.
Assuntos
Colostro/química , Recém-Nascido de Baixo Peso , Lactoferrina/análise , Leite Humano/química , Nascimento Prematuro , Adulto , Aleitamento Materno , Feminino , Humanos , Renda , Lactente , Recém-Nascido , Lactação/fisiologia , Modelos Lineares , Masculino , Análise Multivariada , Peru , Período Pós-Parto , Gravidez , Gravidez Múltipla , Estudos Prospectivos , Adulto JovemRESUMO
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for intestinal disease and hemolytic uremic syndrome (HUS), a serious systemic complication which particularly affects children. In this study, we evaluated whether passive immunization protects from EHEC O157:H7 colonization and renal damage, by using a weaned BALB/c mouse model of infection. Recombinant proteins EspB and the carboxyl-terminal fragment of 280 amino acids of γ-intimin (γ-IntC280) were used in combination with a macrophage-activating lipopeptide-2 (MALP) adjuvant to immunize pregnant mice by the intranasal route. Neonatal mice were allowed to suckle vaccinated or sham-vaccinated dams until weaning when they were challenged by the oral route with a suspension of an E. coli O157:H7 Stx2+ strain. The excretion of the inoculated strain was followed for 72h. All vaccinated dams exhibited elevated serum IgG response against both γ-Int C280 and EspB. Passive immunization of newborn mice resulted in a significant increase in serum IgG titers against γ-Int C280 and a slight increase in EspB-specific antibodies. The neonates from vaccinated dams showed a significant reduction in EHEC O157:H7 colonization 48h post challenge. In addition, the level of plasma urea concentration, a marker of renal failure, was significantly higher in offsprings of sham-vaccinated mice. In conclusion, vaccination of pregnant dams with γ-Int C280 and EspB could reduce colonization and systemic toxicity of EHEC O157:H7 in their suckling offsprings.
Assuntos
Adesinas Bacterianas/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Infecções por Escherichia coli/prevenção & controle , Proteínas de Escherichia coli/imunologia , Vacinas contra Escherichia coli/imunologia , Imunidade Materno-Adquirida , Administração Intranasal , Animais , Anticorpos Antibacterianos/sangue , Escherichia coli O157 , Vacinas contra Escherichia coli/administração & dosagem , Feminino , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos BALB C , Gravidez , Proteínas Recombinantes/imunologiaRESUMO
Escherichia coli O157:H7 is the main causative agent of haemolytic uremic syndrome. Cattle are the main reservoir of these bacteria, and have been shown to develop immune response to colonization. Our aim was to investigate the faecal shedding pattern of E. coli O157:H7 in calves challenged intragastrically with either 10(8) or 10(10) CFU, as well as the ability of specific preexisting antibodies to reduce shedding of the pathogen. Shedding was analysed by direct counting as well as enrichment of rectoanal mucosal swabs. Statistical analysis was performed using a linear model for repeated measures with and without the inclusion of preexisting antibodies against the carboxy-terminal fraction of intimin-γ (γ-intimin C280) as a covariable. Results suggest that there is a statistical difference in the area under the shedding curves between both doses for 14 as well as 28 days after challenge (p = 0.0069 and 0.0209, resp.). This difference is increased when the prechallenge antibodies are taken into account (p = 0.0056 and 0.0185). We concluded that the bacterial dose influences shedding on calves experimentally challenged and that preexisting antibodies against E. coli O157:H7 γ-intimin C280 could partially reduce faecal excretion.
Assuntos
Derrame de Bactérias/imunologia , Infecções por Escherichia coli , Escherichia coli O157 , Proteínas de Escherichia coli/imunologia , Interações Hospedeiro-Patógeno/imunologia , Fosfoproteínas/imunologia , Animais , Anticorpos Antibacterianos/sangue , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/microbiologia , Modelos Animais de Doenças , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli O157/química , Escherichia coli O157/imunologia , Escherichia coli O157/patogenicidade , MasculinoRESUMO
Escherichia coli O157:H7 is responsible for severe intestinal disease and hemolytic uremic syndrome (HUS), a serious systemic complication which particularly affects children. Cattle are the primary reservoir for E. coli O157:H7 and the main source of infection for humans. In this study, we evaluated the ability of transferred maternal colostral antibodies against γ-Intimin C280 and EspB, to protect young weaned calves from E. coli O157:H7 infection. Hyperimmune colostra were obtained by immunization of pregnant cows with a mix of the mentioned antigens. All vaccinated cows mounted a significant IgG response against γ-Intimin C280, and EspB in sera and colostra. Colostrum-fed calves also exhibited high serum IgG titers against γ-Intimin C280 and EspB along with a rise in mucosal γ-Intimin C280-specific IgG antibodies at recto-anal junction and ileum. Additionally, 70 day-old calves received a challenge with E. coli O157:H7 but no reduction in total bacterial shedding or frequency of E. coli O157:H7 excretion from these calves was observed. Most tissue samples showed granulocyte focal infiltrations of the lamina propria and enterocyte erosion. In conclusion, up to the 70th day, the passively acquired γ-Intimin-C280 and EspB-IgG antibodies present in sera and recto-anal mucosa reached a titer insufficient to reduce EHEC O157 shedding and damages of experimentally inoculated young calves.
Assuntos
Adesinas Bacterianas/imunologia , Anticorpos Antibacterianos/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Doenças dos Bovinos/prevenção & controle , Colostro/imunologia , Infecções por Escherichia coli/veterinária , Proteínas de Escherichia coli/imunologia , Animais , Anticorpos Antibacterianos/sangue , Derrame de Bactérias , Bovinos , Doenças dos Bovinos/imunologia , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/prevenção & controle , Escherichia coli O157 , Vacinas contra Escherichia coli/administração & dosagem , Fezes/microbiologia , Feminino , Imunidade Materno-Adquirida , Imunidade nas Mucosas , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , GravidezRESUMO
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of intestinal disease and hemolytic uremic syndrome, a serious systemic complication that particularly affects children. Cattle are primary reservoirs for EHEC O157:H7 and the main source of infection for humans. Vaccination of cattle with different combinations of bacterial virulence factors has shown efficacy in decreasing EHEC O157:H7 shedding. It is, therefore, important to demonstrate whether vaccination of pregnant cows with EHEC O157:H7 induces high titers of transferable antibodies to avoid early colonization of calves by the bacteria. In this study we evaluated the ability of EspA, EspB, the C-terminal fragment of 280 amino acids of γ-intimin (γ-intimin C280) and inactivated Shiga toxin (Stx) 2 proteins to induce specific antibodies in colostrum and their passive transference to colostrum-fed calves. Friesian pregnant cows immunized by the intramuscular route mounted significantly high serum and colostrum IgG responses against EspB and γ-intimin C280 that were efficiently transferred to their calves. Antibodies to EspB and γ-intimin C280 were detected in milk samples of vaccinated cows at d 40 postparturition. Significant Stx2-neutralizing titers were also observed in colostrum from Stx2-vaccinated cows and sera from colostrum-fed calves. The results presented showed that bovine colostrum with increased levels of antibodies against EHEC O157:H7 may be obtained by systemic immunization of pregnant cows, and that these specific antibodies are efficiently transferred to newborn calves by feeding colostrum. Hyperimmune colostrum and milk may be an alternative to protect calves from early colonization by EHEC O157:H7 and a possible key source of antibodies to block colonization and toxic activity of this bacterium.
Assuntos
Adesinas Bacterianas/farmacologia , Anticorpos Antibacterianos/imunologia , Proteínas da Membrana Bacteriana Externa/farmacologia , Bovinos/imunologia , Colostro/imunologia , Escherichia coli O157/imunologia , Proteínas de Escherichia coli/farmacologia , Imunidade Materno-Adquirida/imunologia , Toxina Shiga II/farmacologia , Vacinação/veterinária , Adesinas Bacterianas/imunologia , Animais , Animais Recém-Nascidos/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Escherichia coli/imunologia , Feminino , Gravidez , Toxina Shiga II/imunologiaRESUMO
Cattle are the main reservoir of enterohemorrhagic Escherichia coli O157:H7, a bacterium that, in humans, causes hemorrhagic colitis and hemolytic uremic syndrome (HUS), a life-threatening disease, especially in children and older people. Therefore, the development of vaccines preventing colonization of cattle by E. coli O157:H7 could be a main tool for an HUS control program. In the present study, we evaluated bacterial ghosts (BGs) of E. coli O157:H7 as an experimental vaccine against this pathogen. BGs are empty envelopes of Gram-negative bacteria, which retain the morphological surface make-up of their living counterparts and are produced by controlled expression of the cloned protein E, which causes loss of all the cytoplasm content. In this work, E. coli O157:H7 BGs were used for subcutaneous immunization of calves. The vaccinated animals elicited significant levels of BG-specific IgG but not IgA antibodies in serum. Low levels of IgA and IgG antibodies against BGs were detected in saliva from vaccinated animals. Following oral challenge with E. coli O157:H7, a significant reduction in both the duration and total bacterial shedding was observed in vaccinated calves compared to the nonimmunized group. We demonstrated that systemic vaccination with E. coli O157 BGs provides protection in a bovine experimental model. Further research is needed to reach a higher mucosal immune response leading to an optimal vaccine.
Assuntos
Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/prevenção & controle , Infecções por Escherichia coli/veterinária , Escherichia coli O157/imunologia , Vacinas contra Escherichia coli/imunologia , Animais , Anticorpos Antibacterianos/sangue , Derrame de Bactérias , Bovinos , Doenças dos Bovinos/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/prevenção & controle , Vacinas contra Escherichia coli/administração & dosagem , Imunização/métodos , Imunização/veterinária , Masculino , Distribuição AleatóriaRESUMO
Pets can be reservoirs of Shiga toxin-producing Escherichia coli (STEC) strains. The aim of this study was to examine nine strains belonging to several serotypes (O91:H21, O91:H16, O178:H19, O8:H19, O22:H8, O22:HNT, ONT:H8), previously recovered from cats or dogs. To this end, we assessed a set of additional virulence genes (stx(2) subtype, subAB, ehxA, eae and saa), cytotoxic activity, and genetic relationships with strains isolated from cattle, meat and humans using pulsed-field gel electrophoresis (PFGE). Most of the isolates carried the stx(2) and/or stx(2vh-b) sequences, while only the O91:H21 isolate presented the mucus-activatable stx(2d) variant, as confirmed by sequencing the genes of subunits A and B. All the strains showed cytotoxic activity in cultured cells. One of the two O178:H19, selected for its high level of cytotoxicity in Vero cells, showed the ability to cause functional alterations in the human colon mucosa in vitro. None of the strains possessed the subAB, eae or saa genes and only the strains belonging to serotype O8:H19 carried the ehxA gene. The isolates shared 90-100% similarity by PFGE to epidemiologically unrelated strains of the corresponding serotypes recovered from cattle, meat or humans. Our results demonstrate that dogs and cats may have a role in the infection of humans by STEC, probably serving as a vehicle for bovine strains in the cycle of human infection, and thus emphasize the health risks for owners and their families.