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1.
Int J Food Microbiol ; 348: 109201, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-33930836

RESUMO

Salmonella enterica is frequently implicated in foodborne disease outbreaks associated with fresh-cut fruits. In the U.S., more than one third of fruit-related outbreaks have been linked to two S. enterica serotypes Newport and Typhimurium. Approximately 80% of fruit-related human salmonellosis cases were associated with tomatoes, cantaloupes and cucumbers. In this study, we investigated the population dynamics of S. Newport and S. Typhimurium on fresh-cut tomato, cantaloupe, cucumber and apple under short-term storage conditions. We further compared the transcriptomic profiles of a S. Newport strain on fresh-cut tomato and cantaloupe using high-throughput RNA-seq. We demonstrated that both S. enterica Newport and Typhimurium survived well on various fresh-cut fruit items under refrigeration storage conditions, independent of inoculation levels. However, S. enterica displayed variable survival behaviors on different types of fruits. For example, at 7 d storage, the population of S. enterica reduced less than 0.2 log (p > 0.05) on fresh-cut tomato and cantaloupe, in contrast to ~0.5 log (p < 0.05) on cucumber and apple. RNA-seq analysis suggested that S. enterica mediates its survival on fresh-cut fruits through differentially regulating genes involved in specific carbon utilization and metabolic pathways. Several known bacterial virulence factors (e.g., pag gene) were found to be differentially regulated on fresh-cut tomato and cantaloupe, suggesting a link between the events of food contamination and subsequent human infection. Findings from this study contribute to a better understanding of S. enterica survival mechanisms on fresh-cut produce.


Assuntos
Armazenamento de Alimentos/métodos , Doenças Transmitidas por Alimentos/microbiologia , Frutas/microbiologia , Infecções por Salmonella/transmissão , Salmonella enterica/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Cucumis melo/microbiologia , Cucumis sativus/microbiologia , Surtos de Doenças , Metabolismo Energético/genética , Contaminação de Alimentos , Microbiologia de Alimentos , Humanos , Lycopersicon esculentum/microbiologia , Malus/microbiologia , Infecções por Salmonella/microbiologia , Salmonella enterica/genética , Salmonella enterica/patogenicidade , Sorogrupo , Transcriptoma
2.
Zoonoses Public Health ; 68(2): 131-143, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33455089

RESUMO

Salmonellosis is a major global public health issue; its most common infection, gastroenteritis, accounts for approximately 90 million illnesses and 150,000 mortalities per year. Eradicating salmonellosis requires surveillance, prevention and treatment, entailing large expenditures. However, it is difficult to control Salmonella transmission because it occurs via multiple routes; exotic reptiles are a reservoir of Salmonella and comprise one such route. As the popularity of exotic pets and animal exhibition has increased, human encounters with reptiles have also increased. As a result, reptile-associated salmonellosis (RAS) has been recognized as an emerging disease. The development of antimicrobial resistance in RAS-causing Salmonella sp. requires alternatives to antibiotics. In this study, bacteriophages have been established as an alternative to antibiotics because only target bacteria are lysed; thus, they are promising biocontrol agents. Here, bacteriophage pSal-SNUABM-02, which infects and lyses reptile Salmonella isolates, was isolated and characterized. The morphology, host range, growth traits and stability of the phage were investigated. The phage was assigned to Myoviridae and was stable in the following conditions: pH 5-9, 4-37°C, and ultravioletA/ultravioletB (UVA/UVB) exposure. Salmonella clearance efficacy was tested using planktonic cell lysis activity and biofilm degradation on polystyrene 96-well plates and reptile skin fragments. The phage exhibited vigorous lysis activity against planktonic cells. In in vitro biofilm degradation tests on reptile skin and polystyrene plates, both low- and high-concentration phage treatments lowered bacterial cell viability by approximately 2.5-3 log colony-forming units and also decreased biomass. Thus, bacteriophages are a promising alternative to antibiotics for the prevention and eradication of RAS.


Assuntos
Reservatórios de Doenças/veterinária , Répteis/microbiologia , Infecções por Salmonella/prevenção & controle , Fagos de Salmonella/fisiologia , Zoonoses/microbiologia , Animais , Biofilmes , Humanos , Animais de Estimação/microbiologia , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/transmissão , Zoonoses/prevenção & controle , Zoonoses/transmissão
3.
Viruses ; 12(12)2020 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-33321823

RESUMO

Non-typhoidal Salmonella present a major threat to animal and human health as food-borne infectious agents. We characterized 91 bacterial isolates from Armenia and Georgia in detail, using a suite of assays including conventional microbiological methods, determining antimicrobial susceptibility profiles, matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, serotyping (using the White-Kauffmann-Le Minor scheme) and genotyping (repetitive element sequence-based PCR (rep-PCR)). No less than 61.5% of the isolates were shown to be multidrug-resistant. A new antimicrobial treatment strategy is urgently needed. Phage therapy, the therapeutic use of (bacterio-) phages, the bacterial viruses, to treat bacterial infections, is increasingly put forward as an additional tool for combatting antibiotic resistant infections. Therefore, we used this representative set of well-characterized Salmonella isolates to analyze the therapeutic potential of eleven single phages and selected phage cocktails from the bacteriophage collection of the Eliava Institute (Georgia). All isolates were shown to be susceptible to at least one of the tested phage clones or their combinations. In addition, genome sequencing of these phages revealed them as members of existing phage genera (Felixounavirus, Seunavirus, Viunavirus and Tequintavirus) and did not show genome-based counter indications towards their applicability against non-typhoidal Salmonella in a phage therapy or in an agro-food setting.


Assuntos
Bacteriófagos/fisiologia , Interações Hospedeiro-Patógeno , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonella/virologia , Animais , Antibacterianos/farmacologia , Bacteriófagos/ultraestrutura , Doenças Transmitidas por Alimentos/microbiologia , Geografia Médica , República da Geórgia/epidemiologia , Humanos , Filogenia , Salmonella/classificação , Salmonella/efeitos dos fármacos , Salmonella/isolamento & purificação , Infecções por Salmonella/transmissão
4.
BMC Public Health ; 20(1): 336, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32178656

RESUMO

BACKGROUND: Campylobacter is the most commonly reported causative agent of foodborne bacterial infection in Germany, and contaminated chicken meat is an important source of this zoonotic agent. The aim of this study was to determine the knowledge of consumers in Germany about Campylobacter, Salmonella and Toxoplasma and their transmissibility via meat. In addition, we investigated the level of knowledge between selected consumer groups and whether the results coincided with those of international studies. METHODS: We conducted a cross-sectional survey of 1008 consumers in Germany via an online panel to record, analyse and evaluate the state of knowledge about Campylobacter, Salmonella and Toxoplasma. The participants were selected according to age, gender and federal states to be representative of the German population. RESULTS: Overall, 68.3% of the respondents had never heard of Campylobacter, 20.2% had heard of Campylobacter but did not know how to protect themselves, and only 11.5% knew how to protect themselves from Campylobacter infections. Slightly more than half (52.2%) of the respondents who had at least heard of Campylobacter knew that Campylobacter was transmissible via meat. Knowledge increased significantly with age. Participants over 60 years old knew about Campylobacter almost three times as often as the 16- to 19-year-old comparison group (OR = 2.982). Consumers who had at least a secondary school certificate were almost twice as likely to know about Campylobacter as those who had no school certificate or a lower secondary school certificate (OR = 1.899). Participants who were not actors in the food chain were significantly less frequently informed about Campylobacter than were those who were actors in the food chain. Consumer knowledge of Toxoplasma was better than that of Campylobacter. Consumers have the most knowledge about Salmonella. CONCLUSIONS: Consumers in Germany are predominantly poorly informed about Campylobacter and the transmission route via meat. General knowledge of Toxoplasma is better than that of Campylobacter. Among the three pathogens, consumers are best informed about Salmonella. This finding highlights the importance of making existing information materials more accessible to consumers in the future to increase their knowledge, with the objective of reducing the incidence of Campylobacter infections.


Assuntos
Campylobacter , Conhecimentos, Atitudes e Prática em Saúde , Salmonella , Toxoplasma , Adolescente , Adulto , Infecções por Campylobacter/transmissão , Estudos Transversais , Feminino , Alemanha , Humanos , Masculino , Carne/microbiologia , Pessoa de Meia-Idade , Infecções por Salmonella/transmissão , Toxoplasmose/transmissão , Adulto Jovem
5.
Epidemiol Infect ; 148: e60, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32079547

RESUMO

For outbreaks of gastrointestinal disease, rapid identification of the source is crucial to enable public health intervention and prevent further cases. Outbreak investigation comprises analyses of exposure information from cases and, if required, undertaking analytical epidemiological studies. Hypothesis generation has been reliant on empirical knowledge of exposures historically associated with a given pathogen. Epidemiology studies are resource-intensive and prone to bias, one of the reasons being the difficulties in recruiting appropriate controls. For this paper, the information from cases was compared against pre-defined background exposure information. As exemplars, three past outbreaks were used, one of common and two of rare exposures. Information from historical case trawling questionnaires was used to define background exposure having removed any exposures implicated with the outbreak. The case-background approach showed good sensitivity and specificity, identifying correctly all outbreak-related exposures. One additional exposure related to a retailer was identified and four food items where all cases had been exposed. In conclusion, the case-background method, a development of the case-case design, can be used to assist with hypothesis generation or when a case-control study may not be possible to carry out.


Assuntos
Surtos de Doenças , Exposição Ambiental/estatística & dados numéricos , Projetos de Pesquisa Epidemiológica , Gastroenteropatias/epidemiologia , Adulto , Inglaterra , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saúde Pública , Estudos Retrospectivos , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/transmissão , Adulto Jovem
6.
PLoS Negl Trop Dis ; 14(2): e0008036, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32106221

RESUMO

BACKGROUND: Multi-drug resistant typhoid fever remains an enormous public health threat in low and middle-income countries. However, we still lack a detailed understanding of the epidemiology and genomics of S. Typhi in many regions. Here we have undertaken a detailed genomic analysis of typhoid in urban Dhaka, Bangladesh to unravel the population structure and antimicrobial resistance patterns in S. Typhi isolated between 2004-2016. PRINCIPAL FINDINGS: Whole genome sequencing of 202 S. Typhi isolates obtained from three study locations in urban Dhaka revealed a diverse range of S. Typhi genotypes and AMR profiles. The bacterial population within Dhaka were relatively homogenous with little stratification between different healthcare facilities or age groups. We also observed evidence of exchange of Bangladeshi genotypes with neighboring South Asian countries (India, Pakistan and Nepal) suggesting these are circulating throughout the region. This analysis revealed a decline in H58 (genotype 4.3.1) isolates from 2011 onwards, coinciding with a rise in a diverse range of non-H58 genotypes and a simultaneous rise in isolates with reduced susceptibility to fluoroquinolones, potentially reflecting a change in treatment practices. We identified a novel S. Typhi genotype, subclade 3.3.2 (previously defined only to clade level, 3.3), which formed two localized clusters (3.3.2.Bd1 and 3.3.2.Bd2) associated with different mutations in the Quinolone Resistance Determining Region (QRDR) of gene gyrA. SIGNIFICANCE: Our analysis of S. Typhi isolates from urban Dhaka, Bangladesh isolated over a twelve year period identified a diverse range of AMR profiles and genotypes. The observed increase in non-H58 genotypes associated with reduced fluoroquinolone susceptibility may reflect a change in treatment practice in this region and highlights the importance of continued molecular surveillance to monitor the ongoing evolution of AMR in Dhaka. We have defined new genotypes and lineages of Bangladeshi S. Typhi which will facilitate the identification of these emerging AMR clones in future surveillance efforts.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonella typhi/efeitos dos fármacos , Bangladesh/epidemiologia , DNA Bacteriano/genética , Genoma Bacteriano , Genótipo , Humanos , Internacionalidade , Polimorfismo de Nucleotídeo Único , Estudos Retrospectivos , Infecções por Salmonella/transmissão , Salmonella typhi/genética , Salmonella typhi/isolamento & purificação , Fatores de Tempo , Viagem , População Urbana
7.
PLoS One ; 15(1): e0220484, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31990938

RESUMO

The growing occurrence of multidrug-resistant (MDR) Salmonella enterica in poultry has been reported with public health concern worldwide. We reported, recently, the occurrence of Escherichia coli and Salmonella enterica serovars carrying clinically relevant resistance genes in dairy cattle farms in the Wakiso District, Uganda, highlighting an urgent need to monitor food-producing animal environments. Here, we present the prevalence, antimicrobial resistance, and sequence type of 51 Salmonella isolates recovered from 379 environmental samples from chicken farms in Uganda. Among the Salmonella isolates, 32/51 (62.7%) were resistant to at least one antimicrobial, and 10/51 (19.6%) displayed multiple drug resistance. Through PCR, five replicon plasmids were identified among chicken Salmonella isolates including IncFIIS 17/51 (33.3%), IncI1α 12/51 (23.5%), IncP 8/51 (15.7%), IncX1 8/51 (15.7%), and IncX2 1/51 (2.0%). In addition, we identified two additional replicons through WGS (Whole Genome Sequencing; ColpVC and IncFIB). A significant seasonal difference between chicken sampling periods was observed (p = 0.0017). We conclude that MDR Salmonella highlights the risks posed to animals and humans. Implementing a robust, integrated surveillance system will aid in monitoring MDR zoonotic threats.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos , Plasmídeos/metabolismo , Doenças das Aves Domésticas/epidemiologia , Infecções por Salmonella/epidemiologia , Salmonella enterica/genética , Animais , Antibacterianos/classificação , Antibacterianos/farmacologia , Galinhas/microbiologia , Fazendas , Humanos , Vigilância Imunológica , Plasmídeos/química , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/transmissão , Prevalência , Replicon , Infecções por Salmonella/microbiologia , Infecções por Salmonella/transmissão , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/isolamento & purificação , Estações do Ano , Uganda/epidemiologia , Sequenciamento Completo do Genoma
9.
PLoS One ; 14(9): e0222108, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31479476

RESUMO

Non-typhoidal Salmonella (NTS) infection is one of the major causes of diarrheal disease throughout the world. In recent years, an increase in human S. Javiana infection has been reported from the southern part of the United States. However, the sources and routes of transmission of this Salmonella serotype are not well understood. The objective of this study was to perform a systematic review of the literature to identify risk factors for human S. Javiana infection. Using PRISMA guidelines, we conducted a systematic search in Web of Science, PubMed, and the Morbidity and Mortality Weekly Report (MMWR). Searches returned 63 potential articles, of which 12 articles met all eligibility criteria and were included in this review. A review of the literature indicated that both food and non-food (such as animal contact) exposures are responsible for the transmission of S. Javiana infection to humans. Consumption of fresh produce (tomatoes and watermelons), herbs (paprika-spice), dairy products (cheese), drinking contaminated well water and animal contact were associated with human S. Javiana infections. Based on the findings of this study, control of human S. Javiana infection should include three factors, (a) consumption of drinking water after treatment, (b) safe animal contact, and (c) safe food processing and handling procedures. The risk factors of S. Javiana infections identified in the current study provide helpful insight into the major vehicles of transmission of S. Javiana. Eventually, this will help to improve the risk management of this Salmonella serotype to reduce the overall burden of NTS infection in humans.


Assuntos
Infecções por Salmonella/microbiologia , Salmonella enterica/patogenicidade , Animais , Infecção Hospitalar/microbiologia , Infecção Hospitalar/prevenção & controle , Infecção Hospitalar/transmissão , Microbiologia de Alimentos , Humanos , Fatores de Risco , Gestão de Riscos , Intoxicação Alimentar por Salmonella/microbiologia , Intoxicação Alimentar por Salmonella/prevenção & controle , Intoxicação Alimentar por Salmonella/transmissão , Infecções por Salmonella/prevenção & controle , Infecções por Salmonella/transmissão , Salmonella enterica/classificação , Sorogrupo
10.
Am J Trop Med Hyg ; 101(4): 746-748, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31392950

RESUMO

Salmonella enterica serovar Infantis is causing an increasing number of infections worldwide. Our aim was to describe the characteristics of S. enterica serovar Infantis among patients attended in a hospital of Lima, Peru. Fifty cases of salmonellosis were seen during October 2015-May 2017; Salmonella Infantis was detected in 36% (n = 18) of them, displacing Enteritidis and Typhimurium (n = 13, 26%, each). Seventeen cases caused by Salmonella Infantis were presented as diarrheal illnesses; only one extraintestinal case (bacteremia) was seen in a 1-year-old infant. This serovar is resistant to multiple groups of antimicrobials, showing only fully susceptibility to carbapenems. Compared with Infantis, other serovars analyzed (mainly Enteritidis and Typhimurium) showed a lower frequency of resistance to antimicrobials such as trimethoprim-sulfamethoxazole, ampicillin, and chloramphenicol. The antibiotic with the highest frequency of resistance was ciprofloxacin. Further studies are needed to evaluate the routes of transmission and measures of control of this multidrug-resistant Salmonella.


Assuntos
Antibacterianos/farmacologia , Bacteriemia/microbiologia , Infecções por Salmonella/microbiologia , Salmonella/imunologia , Adolescente , Bacteriemia/epidemiologia , Bacteriemia/transmissão , Carbapenêmicos/farmacologia , Criança , Pré-Escolar , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana Múltipla , Hospitais , Humanos , Lactente , Testes de Sensibilidade Microbiana , Peru/epidemiologia , Salmonella/enzimologia , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/transmissão , Salmonella enterica/enzimologia , Salmonella enterica/imunologia , Sorogrupo
11.
PLoS One ; 14(7): e0220145, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31323053

RESUMO

The epidemiology of human Salmonella enterica infections in Guadeloupe (French West Indies) appears to be specific, with a higher prevalence of the subspecies enterica serovars Panama and Arechavaleta (Panama and Arechavaleta) than in other regions. A study was performed in Guadeloupe to identify the reservoir of Salmonella serovars by comparing their distribution in warm- and cold-blooded animals and in humans living in Guadeloupe and mainland France. Furthermore, a case-control study was conducted in 2012-2013 to identify the main epidemiologic risk factors for S. enterica infection among children under 15 years of age. Between June 2011 and December 2014, feces from 426 reptiles (322 anoles, 69 iguanas and 35 geckos) and 50 frogs distributed throughout Guadeloupe and nearby islands were investigated. The frequency of S. enterica carriage was 15.0% (n = 64) in reptiles but varied by species. The only significant risk factor for S. enterica infection was a more frequent presence of frogs in the houses of cases than in those of controls (P = 0.042); however, isolates were not collected. Panama and Arechavaleta were the two serovars most often recovered between 2005 and 2014 from humans living in Guadeloupe (24.5% (n = 174) and 11.5% (n = 82), respectively), which is in contrast to the low prevalence in mainland France (0.4%). Their presence at low frequencies in wild reptiles (4.6% (n = 3) and 3.1% (n = 2), respectively) and pigs (7.5% (n = 5) and 1.5% (n = 1), respectively) suggests a broad host range, and humans may be infected by indirect or direct contact with animals. These serovars are probably poorly adapted to humans and therefore cause more severe infections. The unusual subspecies houtenae serovar 43:z4,z32:- was a major subspecies in wild reptiles (24.6%, n = 16) and humans (9.4%, n = 67) but was not recovered from warm-blooded animals, suggesting that reptiles plays a key role in human infection.


Assuntos
Reservatórios de Doenças/microbiologia , Répteis/microbiologia , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Infecções por Salmonella/transmissão , Salmonella enterica , Animais , Estudos de Casos e Controles , Guadalupe/epidemiologia , Humanos
12.
Infect Immun ; 87(9)2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31262982

RESUMO

In recent years nontyphoidal Salmonella has emerged as one of the pathogens most frequently isolated from the bloodstream in humans. Only a small group of Salmonella serovars cause this systemic infection, known as invasive nontyphoidal salmonellosis. Here, we present a focused minireview on Salmonella enterica serovar Panama, a serovar responsible for invasive salmonellosis worldwide. S Panama has been linked with infection of extraintestinal sites in humans, causing septicemia, meningitis, and osteomyelitis. The clinical picture is often complicated by antimicrobial resistance and has been associated with a large repertoire of transmission vehicles, including human feces and breast milk. Nonhuman sources of S Panama involve reptiles and environmental reservoirs, as well as food animals, such as pigs. The tendency of S Panama to cause invasive disease may be linked to certain serovar-specific genetic factors.


Assuntos
Infecções por Salmonella/microbiologia , Salmonella enterica/patogenicidade , Farmacorresistência Bacteriana Múltipla , Saúde Global , Humanos , Infecções por Salmonella/transmissão , Salmonella enterica/genética , Virulência
13.
Sci Rep ; 9(1): 10659, 2019 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337777

RESUMO

Wildlife that exploit human-made habitats hosts and spreads bacterial pathogens. This shapes the epidemiology of infectious diseases and facilitates pathogen spill-over between wildlife and humans. This is a global problem, yet little is known about the dissemination potential of pathogen-infected animals. By combining molecular pathogen diagnosis with GPS tracking of pathogen-infected gulls, we show how this knowledge gap could be filled at regional scales. Specifically, we generated pathogen risk maps of Salmonella, Campylobacter and Chlamydia based on the spatial movements of pathogen-infected yellow-legged gulls (Larus michahellis) equipped with GPS recorders. Also, crossing this spatial information with habitat information, we identified critical habitats for the potential transmission of these bacteria in southern Europe. The use of human-made habitats by infected-gulls could potentially increase the potential risk of direct and indirect bidirectional transmission of pathogens between humans and wildlife. Our findings show that pathogen-infected wildlife equipped with GPS recorders can provide accurate information on the spatial spread risk for zoonotic bacteria. Integration of GPS-tracking with classical epidemiological approaches may help to improve zoonosis surveillance and control programs.


Assuntos
Migração Animal/fisiologia , Infecções por Campylobacter/transmissão , Infecções por Chlamydia/transmissão , Infecções por Salmonella/transmissão , Zoonoses/transmissão , Animais , Animais Selvagens , Charadriiformes , Europa (Continente) , Sistemas de Informação Geográfica , Humanos
14.
Zoonoses Public Health ; 66(6): 562-578, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31179637

RESUMO

Livestock meat and offal contribute significantly to human nutrition as sources of high-quality protein and micronutrients. Livestock products are increasingly in demand, particularly in low- and middle-income settings where economies are growing and meat is increasingly seen as an affordable and desirable food item. Demand is also driving intensification of livestock keeping and processing. An unintended consequence of intensification is increased exposure to zoonotic agents, and a contemporary emerging problem is infection with Campylobacter and Salmonella spp. from livestock (avian and mammalian), which can lead to disease, malabsorption and undernutrition through acute and chronic diarrhoea. This can occur at the farm, in households or through the food chain. Direct infection occurs when handling livestock and through bacteria shed into the environment, on food preparation surfaces or around the house and surroundings. This manuscript critically reviews Campylobacter and Salmonella infections in animals, examines the factors affecting colonization and faecal shedding of bacteria of these two genera as well as risk factors for human acquisition of the infection from infected animals or environment and analyses priority areas for preventive actions with a focus on resource-poor settings.


Assuntos
Derrame de Bactérias , Infecções por Campylobacter/veterinária , Campylobacter/isolamento & purificação , Infecções por Salmonella/microbiologia , Salmonella/isolamento & purificação , Zoonoses , Animais , Infecções por Campylobacter/microbiologia , Humanos , Infecções por Salmonella/transmissão
15.
PLoS Genet ; 15(6): e1008233, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31233504

RESUMO

Pathogenic Salmonella strains that cause gastroenteritis are able to colonize and replicate within the intestines of multiple host species. In general, these strains have retained an ability to form the rdar morphotype, a resistant biofilm physiology hypothesized to be important for Salmonella transmission. In contrast, Salmonella strains that are host-adapted or even host-restricted like Salmonella enterica serovar Typhi, tend to cause systemic infections and have lost the ability to form the rdar morphotype. Here, we investigated the rdar morphotype and CsgD-regulated biofilm formation in two non-typhoidal Salmonella (NTS) strains that caused invasive disease in Malawian children, S. Typhimurium D23580 and S. Enteritidis D7795, and compared them to a panel of NTS strains associated with gastroenteritis, as well as S. Typhi strains. Sequence comparisons combined with luciferase reporter technology identified key SNPs in the promoter region of csgD that either shut off biofilm formation completely (D7795) or reduced transcription of this key biofilm regulator (D23580). Phylogenetic analysis showed that these SNPs are conserved throughout the African clades of invasive isolates, dating as far back as 80 years ago. S. Typhi isolates were negative for the rdar morphotype due to truncation of eight amino acids from the C-terminus of CsgD. We present new evidence in support of parallel evolution between lineages of nontyphoidal Salmonella associated with invasive disease in Africa and the archetypal host-restricted invasive serovar; S. Typhi. We hypothesize that the African invasive isolates are becoming human-adapted and 'niche specialized' with less reliance on environmental survival, as compared to gastroenteritis-causing isolates.


Assuntos
Evolução Biológica , Gastroenterite/genética , Infecções por Salmonella/genética , Salmonella typhimurium/genética , África/epidemiologia , Biofilmes/crescimento & desenvolvimento , Criança , Gastroenterite/epidemiologia , Gastroenterite/microbiologia , Humanos , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Infecções por Salmonella/microbiologia , Infecções por Salmonella/transmissão , Salmonella typhimurium/patogenicidade , Transativadores/genética
16.
Int J Food Microbiol ; 298: 1-10, 2019 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-30889473

RESUMO

Fresh betel leaves (Piper betle L.), imported into the UK are a traditional ready-to-eat food consumed by Asian populations. We report here the consolidation of routinely collected data to model the public health risks from consumption of this food. Amongst 2110 samples collected at Border Inspection, wholesale, catering or retail, Salmonella was detected in 488 (23%) of samples tested between 2011 and 2017 and was the most commonly Salmonella-contaminated ready-to-eat food examined by Public Health England during this period. Using data from multiple samples (usually 5) tested per consignment sampled at Border Inspection, contamination levels were calculated by most probable number: seasonal, temporal and country specific differences were detected. Quantitative contamination data was used to estimate the levels present at retail, and a ß-Poisson dose response model the probability of illness was calculated. Using data for products imported from India, the probability of acquiring infection following a single exposure (comprising of a single leaf) was estimated to be between 0.00003 (January-March) and 0.0001 (July-September). Using British Asian population data for individuals over 30 years of age in England in 2011, two estimates of consumption were modelled as 2.1 and 12.8 million servings per annum. Results from the model estimated 160 cases (range 102 to 242) and 960 cases (range 612 to 1456) per year in England for the two consumption estimates and equated to 34 (range 22 to 51) and 204 (range 130 to 310) salmonellosis cases per year reported to national surveillance. Salmonella from 475 of the contaminated samples were further characterised which showed a heterogeneous population structure with 46 S. enterica subsp. Enterica serovars, together with S. enterica subs diarizonae and salamae identified. Isolates from individual consignments were diverse and close genetic relationships between independent isolates were very rare except from within an individual consignment. There were no outbreaks detected as associated with betel leaf consumption. However analysis by whole genome sequencing of the 2014-17 data identified two cases where the clinical isolate had <5 single nucleotide polymorphism differences to isolates from betel leaves which is indicative of a likely epidemiological link and common source of contamination. Due to the diversity of the Salmonella contaminating this product, associations between salmonellosis cases and betel leaf consumption will appear sporadic and unlikely to be detected by current surveillance strategies based on outbreak detection.


Assuntos
Microbiologia de Alimentos , Modelos Estatísticos , Piper betle/microbiologia , Folhas de Planta/microbiologia , Saúde Pública/estatística & dados numéricos , Salmonella/fisiologia , Adulto , Inglaterra/epidemiologia , Humanos , Intoxicação Alimentar por Salmonella/prevenção & controle , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/prevenção & controle , Infecções por Salmonella/transmissão
17.
Zoonoses Public Health ; 66(4): 370-376, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30821071

RESUMO

In the United States, multistate Salmonella outbreaks are most commonly linked to a food source; however, contact with live animals can also result in outbreaks of human illness. To characterize Salmonella outbreaks linked to animal contact and examine differences compared to foodborne outbreaks, we analysed data reported to the Centers for Disease Control and Prevention through the National Outbreak Reporting System (NORS) from 2009 to 2014 with a primary mode of transmission listed as "animal contact" or "food." Four hundred and eighty-four outbreaks with animal contact or foodborne transmission were reported through NORS; of these outbreaks, 99 (20.5%) resulted from Salmonella transmission through animal contact and 385 (79.5%) resulted from foodborne transmission, which resulted in 3,604 (19.8%) and 13,568 (80.2%) illnesses, respectively. A higher proportion of illnesses among children aged <1 year and children aged 1-4 years were linked to animal contact outbreaks compared to foodborne outbreaks (15.2% vs. 1.4%, p < 0.01 and 24.5% vs. 5.6%, p < 0.01, respectively). Illnesses resulting in hospitalizations (OR: 1.81, 95% CI: 1.62, 2.02) were more likely to be associated with animal contact compared to food. Animal contact outbreaks reported to NORS were more likely to be multistate compared to foodborne outbreaks (OR: 5.43, 95% CI: 3.37, 8.76) and had a longer median duration (99.0 days vs. 9.0 days, p < 0.01). Characterizing the differences between outbreaks of illness linked to animal contact and outbreaks linked to food provides useful information to investigators to improve public health response.


Assuntos
Surtos de Doenças/estatística & dados numéricos , Intoxicação Alimentar por Salmonella/epidemiologia , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/transmissão , Salmonella enterica/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Centers for Disease Control and Prevention, U.S. , Criança , Pré-Escolar , Feminino , Hospitalização , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Vigilância em Saúde Pública , Estados Unidos/epidemiologia , Adulto Jovem
18.
Math Biosci Eng ; 16(2): 667-700, 2019 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-30861661

RESUMO

Sanitation and awareness programs play a fundamental role and are much effective public health interventions to control the spread of infectious diseases. In this paper, a nonlinear mathematical model for the control of infectious diseases, such as typhoid fever is proposed and analyzed by considering budget required for sanitation and awareness programs as a dynamic variable. It is assumed that the budget allocation regarding the protection against the disease to warn people and for sanitation increases logistically and its per-capita growth rate increases with the increase in number of infected individuals. In the model formulation, it is assumed that the susceptible individuals contract infection through the direct contact with infected individuals as well as indirectly through bacteria shed in the environment. It is further assumed that a fraction of budget is used to warn people via propagating awareness whereas the remaining part is used for sanitation to reduce the density of bacteria. The condition when budget should spend on sanitation/awareness to reduce the number of infected individuals is obtained. Model analysis reveals that the sanitation and awareness programs have capability to reduce the epidemic threshold and thus control the spread of infection. However, delay in providing funds destabilizes the system and may cause stability switches through Hopf-bifurcation. Numerical simulations are also carried out to support analytical findings.


Assuntos
Controle de Doenças Transmissíveis/métodos , Doenças Transmissíveis/transmissão , Infectologia/métodos , Infecções por Salmonella/transmissão , Saneamento , Algoritmos , Países em Desenvolvimento , Epidemias , Humanos , Índia , Dinâmica não Linear , Saúde Pública , Salmonella typhi , Microbiologia da Água , Poluentes da Água
19.
Epidemiol Infect ; 147: e150, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30869062

RESUMO

Salmonella enterica serovar Wangata (S. Wangata) is an important cause of endemic salmonellosis in Australia, with human infections occurring from undefined sources. This investigation sought to examine possible environmental and zoonotic sources for human infections with S. Wangata in north-eastern New South Wales (NSW), Australia. The investigation adopted a One Health approach and was comprised of three complimentary components: a case-control study examining human risk factors; environmental and animal sampling; and genomic analysis of human, animal and environmental isolates. Forty-eight human S. Wangata cases were interviewed during a 6-month period from November 2016 to April 2017, together with 55 Salmonella Typhimurium (S. Typhimurium) controls and 130 neighbourhood controls. Indirect contact with bats/flying foxes (S. Typhimurium controls (adjusted odds ratio (aOR) 2.63, 95% confidence interval (CI) 1.06-6.48)) (neighbourhood controls (aOR 8.33, 95% CI 2.58-26.83)), wild frogs (aOR 3.65, 95% CI 1.32-10.07) and wild birds (aOR 6.93, 95% CI 2.29-21.00) were statistically associated with illness in multivariable analyses. S. Wangata was detected in dog faeces, wildlife scats and a compost specimen collected from the outdoor environments of cases' residences. In addition, S. Wangata was detected in the faeces of wild birds and sea turtles in the investigation area. Genomic analysis revealed that S. Wangata isolates were relatively clonal. Our findings suggest that S. Wangata is present in the environment and may have a reservoir in wildlife populations in north-eastern NSW. Further investigation is required to better understand the occurrence of Salmonella in wildlife groups and to identify possible transmission pathways for human infections.


Assuntos
Saúde Única , Salmonelose Animal/epidemiologia , Salmonelose Animal/transmissão , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/transmissão , Salmonella/classificação , Salmonella/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Animais Domésticos/microbiologia , Animais Selvagens/microbiologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Transmissão de Doença Infecciosa , Microbiologia Ambiental , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , New South Wales/epidemiologia , Fatores de Risco , Infecções por Salmonella/microbiologia , Salmonelose Animal/microbiologia , Sorogrupo , Adulto Jovem
20.
Foodborne Pathog Dis ; 16(4): 244-255, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30779595

RESUMO

OBJECTIVES: This study aimed to trace the transmission source of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis strains associated with enteric infections in Shanghainese children, and understand the molecular mechanism of resistance to third-generation cephalosporins and ciprofloxacin. MATERIALS AND METHODS: The profiles of pulsed-field gel electrophoresis (PFGE) were compared among the isolates from children, animal, and environment. Antimicrobial susceptibility was determined using the minimal inhibitory concentrations and Kirby-Bauer disk diffusion method. Extended-spectrum ß-lactamase (ESBL) producing isolates mediated by resistance genes were identified using polymerase chain reaction and sequencing. RESULTS: Based on PFGE patterns, 49 (33.1%) of 148 human Salmonella Typhimurium isolates located in the dominant PFGE clusters were genetically related to the isolates from poultry source, environment water, aquatic products, and reptiles, whereas 97 (97.0%) of 100 human Salmonella Enteritidis isolates were genetically related to isolates from poultry and water. The rates of resistance to ceftriaxone among clinical Salmonella Typhimurium and Salmonella Enteritidis isolates were 42.0% and 14.2%, respectively. Besides, 35.1% of Salmonella Typhimurium isolates displayed resistance to ciprofloxacin; 64.9% of Salmonella Typhimurium isolates and 97.0% of Salmonella Enteritidis isolates displayed reduced susceptibility to ciprofloxacin. Of 64 ESBL/AmpC-producing strains, CTX-M, TEM, DHA, and CMY were detected at frequencies of 86.0%, 62.5%, 7.8%, 3.1%, and 3.1%, respectively. CONCLUSIONS: The transmission sources of Salmonella Typhimurium and Salmonella Enteritidis infections in Shanghainese children were diverse. The high prevalence of resistance to third-generation cephalosporins and ciprofloxacin mediated by multiple molecular mechanisms needs continuous monitoring and intervention.


Assuntos
Diarreia Infantil/microbiologia , Microbiologia de Alimentos , Infecções por Salmonella/epidemiologia , Salmonella enteritidis/isolamento & purificação , Salmonella typhimurium/isolamento & purificação , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Ceftriaxona/farmacologia , Ceftriaxona/uso terapêutico , Criança , Serviços de Saúde da Criança , Pré-Escolar , China/epidemiologia , Ciprofloxacina/farmacologia , Ciprofloxacina/uso terapêutico , Busca de Comunicante , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Farmacorresistência Bacteriana Múltipla/genética , Feminino , Humanos , Lactente , Masculino , Infecções por Salmonella/tratamento farmacológico , Infecções por Salmonella/microbiologia , Infecções por Salmonella/transmissão , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/genética , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética
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