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1.
J Exp Med ; 218(2)2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33180929

RESUMO

Typhoid Vi vaccines have been shown to be efficacious in children living in endemic regions; however, a widely accepted correlate of protection remains to be established. We applied a systems serology approach to identify Vi-specific serological correlates of protection using samples obtained from participants enrolled in an experimental controlled human infection study. Participants were vaccinated with Vi-tetanus toxoid conjugate (Vi-TT) or unconjugated Vi-polysaccharide (Vi-PS) vaccines and were subsequently challenged with Salmonella Typhi bacteria. Multivariate analyses identified distinct protective signatures for Vi-TT and Vi-PS vaccines in addition to shared features that predicted protection across both groups. Vi IgA quantity and avidity correlated with protection from S. Typhi infection, whereas higher fold increases in Vi IgG responses were associated with reduced disease severity. Targeted antibody-mediated functional responses, particularly neutrophil phagocytosis, were also identified as important components of the protective signature. These humoral markers could be used to evaluate and develop efficacious Vi-conjugate vaccines and assist with accelerating vaccine availability to typhoid-endemic regions.


Assuntos
Febre Tifoide/imunologia , Vacinas Tíficas-Paratíficas/imunologia , Vacinas Conjugadas/imunologia , Adulto , Carga Bacteriana , Humanos , Imunidade Humoral , Imunogenicidade da Vacina , Imunoglobulina G/sangue , Fatores de Tempo , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/farmacologia , Vacinas Conjugadas/farmacologia
2.
BMC Infect Dis ; 20(1): 843, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33198646

RESUMO

BACKGROUND: Typhoid fever causes global morbidity and mortality and is a significant health burden, particularly in low- and middle-income countries. The direct fecal-oral route is the main transmission mode, but indirect environmental transmission could occur, particularly in urban settings. This study aimed to investigate the burden and trend of typhoid fever, reporting the coverage system between government and private practice and pattern of multidrug-resistant (MDR) typhoid cases in the urban Klang Valley area from 2011 to 2015. METHODS: The data from a cross-sectional study retrieved from the e-Notifikasi System, a national reporting system for communicable diseases provided by the Disease Control Division, Ministry of Health Malaysia and secondary data of all the typhoid cases were obtained from the public and private hospitals and laboratories in Klang Valley. Descriptive analysis was performed to examine the sociodemographic characteristics, spatial mapping was conducted to examine trends, and the crude incidence rates of confirmed typhoid cases and percentage of reporting coverage were calculated. Significant differences between MDR and non-MDR Salmonella typhi were determined in the patient's sociodemographic characteristics, which were analyzed using χ2 test. P values < 0.05 were considered statistically significant. RESULTS: In total, 507 typhoid fever cases were reported in Klang Valley; however, only 265 cases were confirmed by culture tests. The crude incidence rates of confirmed cases were between 0.5 to 0.7 but peaked at 1.42 per 100,000 population in 2015. Most typhoid fever cases were observed among men (55.6%), individuals aged 21 to 30 years (27.6%), Malaysians (86.3%) and individuals of Malay ethnicity (52.1%). The reporting coverage of confirmed cases was 78.9% and non-reporting coverage of unconfirmed typhoid cases was 79.5%. The predictive value positive (PVP) was 89.3, and 7.5% were detected as MDR Salmonella typhi. Statistical significance was found in gender, citizenship and ethnicity regarding MDR Salmonella typhi (p = 0.004, p = 0.008 and p = 0.034, respectively). CONCLUSIONS: The local transmission of typhoid is still prevalent in the Klang Valley despite rapid urbanization and development in recent years. These findings are essential for policy makers to plan and implement focused and effective preventative activities to curb typhoid infection in urban areas.


Assuntos
Efeitos Psicossociais da Doença , Salmonella typhi/isolamento & purificação , Febre Tifoide/epidemiologia , Adolescente , Adulto , Antibacterianos/uso terapêutico , Hemocultura , Criança , Pré-Escolar , Estudos Transversais , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Malásia/epidemiologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Prevalência , Salmonella typhi/efeitos dos fármacos , Febre Tifoide/tratamento farmacológico , Febre Tifoide/microbiologia , Febre Tifoide/transmissão , Adulto Jovem
3.
PLoS One ; 15(11): e0232382, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33211713

RESUMO

Present study aimed at investigating the magnitude of the prevalence and antibiotic resistance among four Salmonella spp. i.e., S. typhi, S. paratyphi A, S. paratyphi B and S. typhimurium. Raw milk and environment samples were collected from the five districts of southern part of the province of Punjab in Pakistan i.e., Multan, Bahawalpur, Lodhran, Dera Ghazi Khan and Muzaffargarh. Extent of antibiotic resistance was also determined and classified as resistant, intermediate and susceptible. District-wise prevalence data on Salmonella spp. in milk and environmental samples indicated higher S. typhi, S. paratyphi B and S. typhimurium count in Bahawalpur, D.G. Khan and Muzaffargarh districts, respectively. Amongst 13 tested antibiotics, chloramphenicol and ofloxacin were found to be the most susceptible against Salmonella spp. Increased emergence of antibacterial resistance was noted with respect to the type of antibiotics among Salmonella spp. isolates. The study suggests serious interventions to be practiced by the farmers and raw milk vendors in animal husbandry and milk marketing, respectively to curb the burden of Salmonella spp. prevalence in milk. Further, active engagement of animal health division and enforcement agencies to ensure sagacious use of antibiotics at farm level may also help in containment of antimicrobial resistance in Salmonella spp.


Assuntos
Antibacterianos/farmacologia , Salmonella typhi/efeitos dos fármacos , Febre Tifoide/epidemiologia , Farmacorresistência Bacteriana Múltipla , Humanos , Paquistão/epidemiologia , Prevalência , Salmonella typhi/isolamento & purificação , Febre Tifoide/tratamento farmacológico , Febre Tifoide/microbiologia
4.
PLoS One ; 15(10): e0241217, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33112899

RESUMO

Typhoid and paratyphoid fevers are common enteric diseases causing disability and death in China. Incidence data of typhoid and paratyphoid between 2004 and 2016 in China were analyzed descriptively to explore the epidemiological features such as age-specific and geographical distribution. Cumulative incidence of both fevers displayed significant decrease nationally, displaying a drop of 73.9% for typhoid and 86.6% for paratyphoid in 2016 compared to 2004. Cumulative incidence fell in all age subgroups and the 0-4 years-old children were the most susceptible ones in recent years. A cluster of three southwestern provinces (Yunnan, Guizhou, and Guangxi) were the top high-incidence regions. Grey model GM (1,1) and seasonal autoregressive integrated moving average (SARIMA) model were employed to extract the long-term trends of the diseases. Annual cumulative incidence for typhoid and paratyphoid were formulated by GM (1,1) as [Formula: see text] and [Formula: see text] respectively. SARIMA (0,1,7) × (1,0,1)12 was selected among a collection of constructed models for high R2 and low errors. The predictive models for both fevers forecasted cumulative incidence to continue the slightly downward trend and maintain the cyclical seasonality in near future years. Such data-driven insights are informative and actionable for the prevention and control of typhoid and paratyphoid fevers as serious infectious diseases.


Assuntos
Modelos Estatísticos , Febre Paratifoide/epidemiologia , Salmonella typhi/isolamento & purificação , Análise Espaço-Temporal , Febre Tifoide/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Febre Paratifoide/microbiologia , Vigilância da População , Projetos de Pesquisa , Fatores de Tempo , Febre Tifoide/microbiologia , Adulto Jovem
5.
Am J Trop Med Hyg ; 103(6): 2515-2517, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32959766

RESUMO

In contrast to enteric fever, reports of secondary hemophagocytic lymphohistiocytosis (HLH) in invasive non-typhoidal salmonellosis are scarce. We report a child with ceftriaxone-resistant invasive Salmonella Enteritidis infection with secondary HLH, who was successfully managed with intravenous meropenem. Secondary HLH in the context of S. Enteritidis has not been described before.


Assuntos
Ceftriaxona/farmacologia , Farmacorresistência Bacteriana , Linfo-Histiocitose Hemofagocítica/complicações , Infecções por Salmonella/microbiologia , Salmonella enteritidis/efeitos dos fármacos , Febre Tifoide/patologia , Antibacterianos/uso terapêutico , Criança , Humanos , Masculino , Meropeném/uso terapêutico , Infecções por Salmonella/patologia
6.
Proc Natl Acad Sci U S A ; 117(39): 24443-24449, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32900928

RESUMO

Polysaccharide-protein conjugates have been developed to overcome the T-independent response, hyporesponsiveness to repeated vaccination, and poor immunogenicity in infants of polysaccharides. To address the impact of polysaccharide length, typhoid conjugates made with short- and long-chain fractions of Vi polysaccharide with average sizes of 9.5, 22.8, 42.7, 82.0, and 165 kDa were compared. Long-chain-conjugated Vi (165 kDa) induced a response in both wild-type and T cell-deficient mice, suggesting that it maintains a T-independent response. In marked contrast, short-chain Vi (9.5 to 42.7 kDa) conjugates induced a response in wild-type mice but not in T cell-deficient mice, suggesting that the response is dependent on T cell help. Mechanistically, this was explained in neonatal mice, in which long-chain, but not short-chain, Vi conjugate induced late apoptosis of Vi-specific B cells in spleen and early depletion of Vi-specific B cells in bone marrow, resulting in hyporesponsiveness and lack of long-term persistence of Vi-specific IgG in serum and IgG+ antibody-secreting cells in bone marrow. We conclude that while conjugation of long-chain Vi generates T-dependent antigens, the conjugates also retain T-independent properties, leading to detrimental effects on immune responses. The data reported here may explain some inconsistencies observed in clinical trials and help guide the design of effective conjugate vaccines.


Assuntos
Proteínas de Bactérias/administração & dosagem , Polissacarídeos Bacterianos/administração & dosagem , Vacinas contra Salmonella/administração & dosagem , Salmonella typhi/imunologia , Linfócitos T/imunologia , Febre Tifoide/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Linfócitos B/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Feminino , Humanos , Imunoglobulina G/imunologia , Masculino , Camundongos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/imunologia , Vacinas contra Salmonella/genética , Vacinas contra Salmonella/imunologia , Salmonella typhi/genética , Febre Tifoide/microbiologia , Febre Tifoide/prevenção & controle , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/genética , Vacinas Conjugadas/imunologia
7.
PLoS Negl Trop Dis ; 14(8): e0008530, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32804950

RESUMO

We evaluated the protection conferred by a first documented visit for clinical care of typhoid fever against recurrent typhoid fever prompting a visit. This study takes advantage of multi-year follow-up of a population with endemic typhoid participating in a cluster-randomized control trial of Vi capsular polysaccharide typhoid vaccine in Kolkata, India. A population of 70,566 individuals, of whom 37,673 were vaccinated with one dose of either Vi vaccine or a control (Hepatitis A) vaccine, were observed for four years. Surveillance detected 315 first typhoid visits, among whom 4 developed subsequent typhoid, 3 due to reinfection, defined using genomic criteria and corresponding to -124% (95% CI: -599, 28) protection by the initial illness. Point estimates of protection conferred by an initial illness were negative or negligible in both vaccinated and non-vaccinated subjects, though confidence intervals around the point estimates were wide. These data provide little support for a protective immunizing effect of clinically treated typhoid illness, though modest levels of protection cannot be excluded.


Assuntos
Febre Tifoide/epidemiologia , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/administração & dosagem , Anticorpos Antibacterianos , Humanos , Índia/epidemiologia , Salmonella typhi/imunologia , Febre Tifoide/imunologia , Vacinas Tíficas-Paratíficas/uso terapêutico , Vacinação
9.
Sci Rep ; 10(1): 13581, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32788681

RESUMO

Salmonella enterica serovar Typhi (S. Typhi) causes substantial morbidity and mortality worldwide, particularly among young children. Humans develop an array of mucosal immune responses following S. Typhi infection. Whereas the cellular mechanisms involved in S. Typhi infection have been intensively studied, very little is known about the early chromatin modifications occurring in the human gut microenvironment that influence downstream immune responses. To address this gap in knowledge, cells isolated from human terminal ileum exposed ex vivo to the wild-type S. Typhi strain were stained with a 33-metal-labeled antibody panel for mass cytometry analyses of the early chromatin modifications modulated by S. Typhi. We measured the cellular levels of 6 classes of histone modifications, and 1 histone variant in 11 major cell subsets (i.e., B, CD3 + T, CD4 + T, CD8 + T, NK, TCR-γδ, Mucosal associated invariant (MAIT), and NKT cells as well as monocytes, macrophages, and epithelial cells). We found that arginine methylation might regulate the early-differentiation of effector-memory CD4+ T-cells following exposure to S. Typhi. We also found S. Typhi-induced post-translational modifications in histone methylation and acetylation associated with epithelial cells, NKT, MAIT, TCR-γδ, Monocytes, and CD8 + T-cells that are related to both gene activation and silencing.


Assuntos
Epigênese Genética/imunologia , Íleo/imunologia , Imunidade nas Mucosas/imunologia , Membrana Mucosa/imunologia , Salmonella typhi/imunologia , Febre Tifoide/imunologia , Acetilação , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/microbiologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/microbiologia , Epigênese Genética/genética , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Microbioma Gastrointestinal/imunologia , Código das Histonas , Humanos , Íleo/citologia , Íleo/microbiologia , Imunidade nas Mucosas/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/microbiologia , Metilação , Membrana Mucosa/metabolismo , Salmonella typhi/fisiologia , Febre Tifoide/microbiologia
10.
Am J Trop Med Hyg ; 103(4): 1630-1634, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32815509

RESUMO

COVID-19 is a global pandemic which has seriously impacted the economy of nations. Access to essential medicines is of utmost importance. This study examined the impacts of the COVID-19 pandemic on the ease of access to essential medicines by end users. A cross-sectional survey using electronic questionnaires was conducted on study participants across the 36 states of Nigeria. They were assessed on sociodemographics, health characteristics, and challenges in accessing essential medicines during the COVID-19 pandemic. Data obtained were analyzed using the Statistical Package for the Social Sciences (SPSS version 20, IBM, Armonk, NY) with overall impact of the pandemic operationalized as < 60.0% or ≥ 60.0% access to essential medicines by respondents as maximal and minimal impact, respectively. The results showed that 35.2% of the respondents managing chronic illnesses had difficulties accessing essential medicines during the COVID-19 lockdown, with 84.0% experiencing deteriorating chronic health conditions in the light of difficulty in accessing their medicines. The proportion of respondents who sourced for orthodox medicines before COVID-19 lockdown (98.4%) was significantly (P < 0.05) higher than that of those who sourced for the same during the lockdown (89.0%). Increase in cost of medicines was observed by 77.7% of participants, with 73.9% of respondents living with chronic illness affirming that their income was negatively affected by the pandemic. The COVID-19 pandemic had minimal impact on consumers' ability to access essential medicines. However, important challenges identified were poor availability of means of transportation, reduced income, and high cost of medicines, as well as fear of contracting the virus.


Assuntos
Infecções por Coronavirus/epidemiologia , Pandemias , Pneumonia Viral/epidemiologia , Medicamentos sob Prescrição/provisão & distribução , Quarentena/psicologia , Adolescente , Adulto , Idoso , Betacoronavirus/patogenicidade , Criança , Pré-Escolar , Resfriado Comum/tratamento farmacológico , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Estudos Transversais , Diabetes Mellitus/tratamento farmacológico , Medo/psicologia , Feminino , Humanos , Hipertensão/tratamento farmacológico , Lactente , Malária/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Nigéria/epidemiologia , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia , Saúde Pública/ética , Inquéritos e Questionários , Febre Tifoide/tratamento farmacológico
12.
PLoS Pathog ; 16(7): e1008591, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32645118

RESUMO

Reactive arthritis, an autoimmune disorder, occurs following gastrointestinal infection with invasive enteric pathogens, such as Salmonella enterica. Curli, an extracellular, bacterial amyloid with cross beta-sheet structure can trigger inflammatory responses by stimulating pattern recognition receptors. Here we show that S. Typhimurium produces curli amyloids in the cecum and colon of mice after natural oral infection, in both acute and chronic infection models. Production of curli was associated with an increase in anti-dsDNA autoantibodies and joint inflammation in infected mice. The negative impacts on the host appeared to be dependent on invasive systemic exposure of curli to immune cells. We hypothesize that in vivo synthesis of curli contributes to known complications of enteric infections and suggest that cross-seeding interactions can occur between pathogen-produced amyloids and amyloidogenic proteins of the host.


Assuntos
Artrite Infecciosa/imunologia , Proteínas de Bactérias/imunologia , Febre Tifoide/imunologia , Animais , Anticorpos Antinucleares/imunologia , Artrite Experimental/imunologia , Artrite Experimental/metabolismo , Artrite Infecciosa/metabolismo , Proteínas de Bactérias/biossíntese , Intestino Grosso/imunologia , Intestino Grosso/microbiologia , Camundongos , Febre Tifoide/metabolismo
14.
Folia Med Cracov ; 60(1): 25-32, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32658209

RESUMO

Outbreaks of typhoid fever for centuries decimated armies, cities and large hosts of people. Discovery of an agent causing such a grave disease became one of the most important achievements of bacteriology - science, which had experienced rapid development in the last quarter of the 19th century and changed the course of our civilization.The article deals with the discovery of Tadeusz Browicz, Polish anatomopathologist, who in 1874 reported about rod-shaped "parasites" in viscera of typhoid fever victim. His achievement became shaded by the later discoveries of Eberth, Klebs and Gaffky, but as authors stated below, Browicz should be recognized with mentioned scientists as a co-discoverer of the typhoid fever bacillus.


Assuntos
Surtos de Doenças/história , Salmonella typhi/isolamento & purificação , Febre Tifoide/diagnóstico , Febre Tifoide/história , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Achados Incidentais , Polônia/epidemiologia , Febre Tifoide/epidemiologia
15.
Am J Trop Med Hyg ; 103(3): 1032-1038, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32720632

RESUMO

Transcutaneous vaccination can induce both mucosal and systemic immune responses. However, there are few data on anti-polysaccharide responses following transcutaneous vaccination of polysaccharides, despite the role that anti-polysaccharide responses play in protecting against intestinal mucosal and respiratory pathogens. Whether transcutaneous vaccination with a conjugate polysaccharide vaccine would be able to induce memory responses is also unknown. To address this, we transcutaneously vaccinated mice with virulence antigen (Vi) polysaccharide of Salmonella enterica serovar Typhi (the cause of typhoid fever), either in unconjugated or conjugated form (the latter as a Vi-DT conjugate). We also assessed the ability of the immunoadjuvant cholera toxin to impact responses following vaccination. We found that presenting Vi in a conjugate versus nonconjugate form transcutaneously resulted in comparable serum IgG responses but higher serum and lamina propria lymphocyte IgA anti-Vi responses, as well as increased IgG memory responses. The addition of immunoadjuvant did not further increase these responses; however, it boosted fecal IgA and serum IgG anti-Vi responses. Our results suggest that transcutaneous vaccination of a conjugate vaccine can induce systemic as well as enhanced mucosal and memory B-cell anti-polysaccharide responses.


Assuntos
Anticorpos Antibacterianos/sangue , Imunidade Humoral/efeitos dos fármacos , Imunidade nas Mucosas/efeitos dos fármacos , Salmonella typhi/imunologia , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/administração & dosagem , Vacinação/métodos , Administração Cutânea , Animais , Modelos Animais de Doenças , Feminino , Humanos , Esquemas de Imunização , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Memória Imunológica/efeitos dos fármacos , Camundongos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/imunologia , Salmonella typhi/efeitos dos fármacos , Salmonella typhi/patogenicidade , Febre Tifoide/imunologia , Febre Tifoide/microbiologia , Vacinas Tíficas-Paratíficas/biossíntese , Vacinas Conjugadas
16.
Am J Trop Med Hyg ; 103(3): 1020-1031, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32700668

RESUMO

Typhoid fever transmission occurs through ingestion of food or water contaminated with Salmonella Typhi, and case-control studies are often conducted to identify outbreak sources and transmission vehicles. However, there is no current summary of the associations among water, sanitation, and hygiene (WASH); and food exposures and typhoid from case-control studies. We conducted a systematic review and meta-analysis of case-control studies to evaluate the associations among typhoid fever and predicted WASH or food exposure risk factors (13), and protective factors (7). Overall, 19 manuscripts describing 22 case-control studies were included. Two studies were characterized as having low risk of bias, one as medium risk, and 19 as high risk. In total, nine of 13 predicted risk factors were associated with increased odds of typhoid (odds ratio [OR] = 1.4-2.4, I 2 = 30.5-74.8%.), whereas five of seven predicted protective factors were associated with lower odds of typhoid (OR = 0.52-0.73, I 2 = 38.7-84.3%). In five types of sensitivity analyses, two (8%) of 26 summary associations changed significance from the original analysis. Results highlight the following: the importance of household hygiene transmission pathways, the need for further research around appropriate food interventions and the risk of consuming specific foods and beverages outside the home, and the absence of any observed association between sanitation exposures and typhoid fever. We recommend that typhoid interventions focus on interrupting household transmission routes and that future studies provide more detailed information about WASH and food exposures to inform better targeted interventions.


Assuntos
Surtos de Doenças , Desinfecção das Mãos , Salmonella typhi/patogenicidade , Febre Tifoide/epidemiologia , Febre Tifoide/prevenção & controle , Estudos de Casos e Controles , Microbiologia de Alimentos , Humanos , Razão de Chances , Fatores de Risco , Saneamento/métodos , Febre Tifoide/microbiologia , Microbiologia da Água , Abastecimento de Água/métodos
17.
BMC Infect Dis ; 20(1): 422, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32552753

RESUMO

BACKGROUND: In Kenya, typhoid fever and invasive non-typhoidal salmonellosis present a huge burden of disease, especially in poor-resource settings where clean water supply and sanitation conditions are inadequate. The epidemiology of both diseases is poorly understood in terms of severity and risk factors. The aim of the study was to determine the disease burden and spatial distribution of salmonellosis, as well as socioeconomic and environmental risk factors for these infections, in a large informal settlement near the city of Nairobi, from 2013 to 2017. METHODS: Initially, a house-to-house baseline census of 150,000 population in Mukuru informal settlement was carried out and relevant socioeconomic, demographic, and healthcare utilization information was collected using structured questionnaires. Salmonella bacteria were cultured from the blood and faeces of children < 16 years of age who reported at three outpatient facilities with fever alone or fever and diarrhea. Tests of association between specific Salmonella serotypes and risk factors were conducted using Pearson Chi-Square (χ2) test. RESULTS: A total of 16,236 children were recruited into the study. The prevalence of bloodstream infections by Non-Typhoidal Salmonella (NTS), consisting of Salmonella Typhimurium/ Enteriditis, was 1.3%; Salmonella Typhi was 1.4%, and this was highest among children < 16 years of age. Occurrence of Salmonella Typhimurium/ Enteriditis was not significantly associated with rearing any domestic animals. Rearing chicken was significantly associated with high prevalence of S. Typhi (2.1%; p = 0.011). The proportion of children infected with Salmonella Typhimurium/ Enteriditis was significantly higher in households that used water pots as water storage containers compared to using water directly from the tap (0.6%). Use of pit latrines and open defecation were significant risk factors for S. Typhi infection (1.6%; p = 0.048). The proportion of Salmonella Typhimurium/ Enteriditis among children eating street food 4 or more times per week was higher compared to 1 to 2 times/week on average (1.1%; p = 0.032). CONCLUSION: Typhoidal and NTS are important causes of illness in children in Mukuru informal settlement, especially among children less than 16 years of age. Improving Water, Sanitation and Hygiene (WASH) including boiling water, breastfeeding, hand washing practices, and avoiding animal contact in domestic settings could contribute to reducing the risk of transmission of Salmonella disease from contaminated environments.


Assuntos
Infecções por Salmonella/epidemiologia , Salmonella typhi/imunologia , Salmonella typhimurium/imunologia , Febre Tifoide/epidemiologia , Adolescente , Animais , Galinhas , Criança , Pré-Escolar , Características da Família , Fezes/microbiologia , Feminino , Humanos , Higiene , Lactente , Recém-Nascido , Quênia/epidemiologia , Masculino , Áreas de Pobreza , Prevalência , Fatores de Risco , Infecções por Salmonella/microbiologia , Salmonella typhi/isolamento & purificação , Salmonella typhimurium/isolamento & purificação , Saneamento , Testes Sorológicos , Febre Tifoide/microbiologia
18.
Int J Infect Dis ; 97: 334-336, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32569838

RESUMO

OBJECTIVES: Enteric fever remains an important diagnostic and treatment challenge in febrile children living in the tropics. In the context of a national Salmonella enterica serovar Paratyphi A outbreak, the objective of this retrospective study was to compare features of S. Typhi and S. Paratyphi A infections in Cambodian children. METHODS: Clinical and laboratory features were reviewed for 192 blood culture-confirmed children with S. Typhi and S. Paratyphi A infections presenting to a paediatric referral hospital in Siem Reap, 2012-2016. RESULTS: Children with S. Typhi infections were younger, were more likely to have chills and/or diarrhoea, and were more frequently hospitalized than those with S. Paratyphi A infections. Over three quarters (88.3%) of S. Typhi isolates were multidrug-resistant, compared to none of the S. Paratyphi A. CONCLUSIONS: In this small study of Cambodian children, S. Typhi infections were more severe than S. Paratyphi A infections. Antibiotic resistance limits treatment options for enteric fever in this population.


Assuntos
Febre Paratifoide/microbiologia , Salmonella paratyphi A/fisiologia , Salmonella typhi/fisiologia , Febre Tifoide/microbiologia , Adolescente , Antibacterianos/administração & dosagem , Camboja/epidemiologia , Criança , Pré-Escolar , Feminino , Hospitais Pediátricos/estatística & dados numéricos , Humanos , Lactente , Masculino , Febre Paratifoide/tratamento farmacológico , Febre Paratifoide/epidemiologia , Estudos Retrospectivos , Salmonella paratyphi A/genética , Salmonella paratyphi A/isolamento & purificação , Salmonella typhi/genética , Salmonella typhi/isolamento & purificação , Febre Tifoide/tratamento farmacológico , Febre Tifoide/epidemiologia
19.
Artigo em Inglês | MEDLINE | ID: mdl-32526179

RESUMO

In this issue of Cell Host and Microbe, Lee et al. define the glycan binding specificity of a variant of typhoid toxin produced by a non-typhoidal Salmonellae serotype. The authors elegantly demonstrate that tissue and host specificity of the toxin are related to specific glycan binding characteristics of the toxin.


Assuntos
Febre Tifoide , Humanos , Lectinas , Especificidade de Órgãos , Polissacarídeos , Salmonella , Virulência
20.
Am J Trop Med Hyg ; 103(2): 665-671, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32588803

RESUMO

Blood cultures (BCs) detect an estimated 50% of typhoid fever cases. There is need for validated clinical criteria to define cases that are BC negative, both to help direct empiric antibiotic treatment and to better evaluate the magnitude of protection conferred by typhoid vaccines. To derive and validate a clinical rule for defining BC-negative typhoid fever, we assessed, in a cluster-randomized effectiveness trial of Vi-polysaccharide (ViPS) typhoid vaccine in Kolkata, India, 14,797 episodes of fever lasting at least 3 days during 4 years of comprehensive, BC-based surveillance of 70,865 persons. A recursive partitioning algorithm was used to develop a decision rule to predict BC-proven typhoid cases with a diagnostic specificity of 97-98%. To validate this rule as a definition for BC-negative typhoid fever, we assessed whether the rule defined culture-negative syndromes prevented by ViPS vaccine. In a training subset of individuals, we identified the following two rules: rule 1: patients aged < 15 years with prolonged fever accompanied by a measured body temperature ≥ 100°F, headache, and nausea; rule 2: patients aged ≥ 15 years with prolonged fever accompanied by nausea and palpable liver but without constipation. The adjusted protective efficacy of ViPS against clinical typhoid defined by these rules in persons aged ≥ 2 years in a separate validation subset was 33% (95% CI: 4-53%). We have defined and validated a clinical rule for predicting BC-negative typhoid fever using a novel vaccine probe approach. If validated in other settings, this rule may be useful to guide clinical care and to enhance typhoid vaccine evaluations.


Assuntos
Febre/fisiopatologia , Cefaleia/fisiopatologia , Fígado/patologia , Náusea/fisiopatologia , Febre Tifoide/diagnóstico , Adolescente , Adulto , Algoritmos , Hemocultura , Criança , Pré-Escolar , Regras de Decisão Clínica , Árvores de Decisões , Humanos , Índia , Aprendizado de Máquina , Palpação , Polissacarídeos Bacterianos/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Sensibilidade e Especificidade , Fatores de Tempo , Febre Tifoide/fisiopatologia , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas/uso terapêutico , Adulto Jovem
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