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1.
Biofouling ; 36(1): 101-112, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31997643

RESUMEN

Although disinfection procedures are widely implemented in food environments, bacteria can survive and present increased virulence/resistance. Since little is known about these phenomena regarding biofilms, this study aimed to investigate the effect of chemical disinfection on biofilm-derived cells of Salmonella Enteritidis. Using a reference strain (NCTC 13349) and a food isolate (350), biofilm susceptibility to benzalkonium chloride (BAC), sodium hypochlorite (SH) and hydrogen peroxide (HP) was evaluated and biofilms were exposed to sub-lethal concentrations of each disinfectant. Biofilm-derived cells were characterized for their biofilm forming ability, antibiotic resistance and expression of virulence-associated genes. Except for a few instances, disinfectant exposure did not alter antibiotic susceptibility. However, SH and HP exposure enhanced the biofilm forming ability of Salmonella Enteritidis NCTC 13349. After BAC and HP exposure, biofilm-derived cells presented a down-regulation of rpoS. Exposure to BAC also revealed an up-regulation of invA, avrA and csgD on Salmonella Enteritidis NCTC 13349. The results obtained suggest that biofilm-derived cells that survive disinfection may represent an increased health risk.


Asunto(s)
Antibacterianos/farmacología , Biopelículas/efectos de los fármacos , Desinfectantes/farmacología , Desinfección/métodos , Farmacorresistencia Bacteriana/efectos de los fármacos , Salmonella enteritidis/efectos de los fármacos , Virulencia , Compuestos de Benzalconio/farmacología , Biopelículas/crecimiento & desarrollo , Farmacorresistencia Bacteriana/genética , Expresión Génica/efectos de los fármacos , Genes Bacterianos/efectos de los fármacos , Salmonella enteritidis/genética , Salmonella enteritidis/crecimiento & desarrollo , Salmonella enteritidis/patogenicidad , Hipoclorito de Sodio/farmacología , Virulencia/efectos de los fármacos , Virulencia/genética
2.
PLoS Pathog ; 15(12): e1008152, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31800631

RESUMEN

Pathogenicity island excision is a phenomenon that occurs in several Salmonella enterica serovars and other members of the family Enterobacteriaceae. ROD21 is an excisable pathogenicity island found in the chromosome of S. Enteritidis, S. Dublin and S. Typhi among others, which contain several genes encoding virulence-associated proteins. Excision of ROD21 may play a role in the ability of S. Enteritidis to cause a systemic infection in mice. Our previous studies have shown that Salmonella strains unable to excise ROD21 display a reduced ability to colonize the liver and spleen. In this work, we determined the kinetics of ROD21 excision in vivo in C57BL/6 mice and its effect on virulence. We quantified bacterial burden and excision frequency in different portions of the digestive tract and internal organs throughout the infection. We observed that the frequency of ROD21 excision was significantly increased in the bacterial population colonizing mesenteric lymph nodes at early stages of the infective cycle, before 48 hours post-infection. In contrast, excision frequency remained very low in the liver and spleen at these stages. Interestingly, excision increased drastically after 48 h post infection, when intestinal re-infection and mortality begun. Moreover, we observed that the inability to excise ROD21 had a negative effect on S. Enteritidis capacity to translocate from the intestine to deeper organs, which correlates with an abnormal transcription of invA in the S. Enteritidis strain unable to excise ROD21. These results suggest that excision of ROD21 is a genetic mechanism required by S. Enteritidis to produce a successful invasion of the intestinal epithelium, a step required to generate systemic infection in mice.


Asunto(s)
Islas Genómicas/genética , Mucosa Intestinal/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/genética , Salmonella enteritidis/patogenicidad , Animales , Ratones , Ratones Endogámicos C57BL , Virulencia/genética
3.
PLoS Negl Trop Dis ; 13(10): e0007782, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31609964

RESUMEN

BACKGROUND: Salmonella Typhimurium and Enteritidis are major causes of bloodstream infection in children in sub-Saharan Africa. This study assessed evidence for their zoonotic versus human reservoir. METHODS: Index patients were children with blood culture confirmed Salmonella infection recruited during a microbiological surveillance study in Nanoro, rural Burkina between May 2013 and August 2014. After consent, their households were visited. Stool from household members and livestock (pooled samples per species) as well as drinking water were cultured for Salmonella. Isolates with identical serotype obtained from index patient and any household sample were defined as "paired isolates" and assessed for genetic relatedness by multilocus variable number tandem-repeat analysis (MLVA) and whole-genome sequencing (WGS). RESULTS: Twenty-nine households were visited for 32/42 (76.2%) eligible index patients: two households comprised two index patients each, and in a third household the index patient had a recurrent infection. Among the 32 index patients, serotypes were Salmonella Typhimurium (n = 26), Salmonella Enteritidis (n = 5) and Salmonella Freetown (n = 1). All Typhimurium isolates were sequence type (ST)313. Median delay between blood culture sampling and household visits was 13 days (range 6-26). Salmonella was obtained from 16/186 (8.6%) livestock samples (13 serotypes) and 18/290 (6.2%) household members (9 serotypes). None of the water samples yielded Salmonella. Paired Salmonella Typhimurium isolates were obtained from three households representing four index patients. MLVA types were identical in two pairs and similar in the third (consisting of two index patients and one household member). WGS showed a strong genetic relatedness with 0 to 2 core genome SNPs difference between pairs on a household level. Livestock samples did not yield any Salmonella Typhimurium or Salmonella Enteritidis, and the latter was exclusively obtained from blood culture. Other serotypes shared by human and/or livestock carriers in the same household were Salmonella Derby, Drac, Tennessee and Muenster. CONCLUSIONS/SIGNIFICANCE: The current study provides further evidence of a human reservoir for invasive non-Typhoidal Salmonella (iNTS) in sub-Saharan Africa.


Asunto(s)
Reservorios de Enfermedades/microbiología , Composición Familiar , Infecciones por Salmonella/microbiología , Salmonella/clasificación , Salmonella/aislamiento & purificación , Adolescente , Animales , Burkina Faso/epidemiología , Niño , Preescolar , Monitoreo del Ambiente , Heces/microbiología , Femenino , Humanos , Lactante , Ganado , Masculino , Tipificación de Secuencias Multilocus , Filogenia , Salmonella/genética , Infecciones por Salmonella/epidemiología , Salmonella enterica/genética , Salmonella enterica/aislamiento & purificación , Salmonella enteritidis/genética , Salmonella enteritidis/aislamiento & purificación , Salmonella typhimurium/genética , Salmonella typhimurium/aislamiento & purificación , Serogrupo , Microbiología del Agua , Secuenciación Completa del Genoma
4.
BMC Vet Res ; 15(1): 319, 2019 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-31488137

RESUMEN

BACKGROUND: Small non-coding RNAs (sRNAs) regulate bacterial gene expression at the post-transcriptional level. STnc640 is a type of sRNA that was identified in Salmonella Typhimurium. RESULTS: In this study, STnc640 in Salmonella Enteritidis was confirmed to be an Hfq-dependent sRNA. TargetRNA software analysis showed that fimbrial genes fimA and bcfA were likely to be the target genes of STnc640. To investigate the target mRNAs and function of STnc640 in pathogenicity, we constructed the deletion mutant strain 50336△stnc640 and the complemented strain 50336△stnc640/pstnc640 in Salmonella Enteritidis 50336. The RT-qPCR results showed that the mRNA level of fimA was decreased, while bcfA was unchanged in 50336△stnc640 compared with that in the wild type (WT) strain. The adhesion ability of 50336△stnc640 to Caco-2 cells was increased compared to the 50336 WT strain. The virulence of 50336△stnc640 was enhanced in a one-day-old chicken model of S. Enteritidis disease as determined by quantifying the 50% lethal dose (LD50) of the bacterial strains. CONCLUSIONS: The results demonstrate that STnc640 contributes to the virulence of Salmonella Enteritidis.


Asunto(s)
Antígenos Bacterianos/genética , Proteínas Fimbrias/genética , Regulación Bacteriana de la Expresión Génica , ARN Bacteriano/fisiología , ARN Pequeño no Traducido/fisiología , Salmonella enteritidis/genética , Salmonella enteritidis/patogenicidad , Animales , Adhesión Bacteriana/genética , Células CACO-2 , Pollos , Femenino , Humanos , Masculino , Enfermedades de las Aves de Corral/virología , Salmonelosis Animal/virología , Eliminación de Secuencia , Virulencia/genética
5.
Future Microbiol ; 14: 885-898, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31368788

RESUMEN

Aim: The aim of this study is to formulate a new single nonselective pre-enrichment medium (ELSS) that can support the concurrent growth of four major foodborne pathogens containing E. coli O157: H7, L. monocytogenes, S. aureus and S. enterica serovar Entertidis to develop a multiplex TaqMan Real-time PCR (mRT-PCR). Methods: The mRT-PCR with a new pre-enrichment was carried out for simultaneous detection and quantification of these foodborne bacteria. Results: By using mRT-PCR after 16 h pre-enrichment in ELSS, the detection limit of each pathogen was 1 CFU/25 ml contaminated milk, as well as inclusivity and exclusivity reached 100%. Conclusion: The mRT-PCR assay with pre-enrichment step is a fast and reliable technique for detecting single or multiple pathogens in food products.


Asunto(s)
Bacterias/genética , Técnicas Bacteriológicas/métodos , Microbiología de Alimentos/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Leche/microbiología , Animales , Bacterias/crecimiento & desarrollo , Bacterias/aislamiento & purificación , Medios de Cultivo , ADN Bacteriano/genética , Escherichia coli O157/genética , Escherichia coli O157/crecimiento & desarrollo , Escherichia coli O157/aislamiento & purificación , Listeria monocytogenes/genética , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Salmonella enteritidis/genética , Salmonella enteritidis/crecimiento & desarrollo , Salmonella enteritidis/aislamiento & purificación , Sensibilidad y Especificidad , Staphylococcus aureus/genética , Staphylococcus aureus/crecimiento & desarrollo , Staphylococcus aureus/aislamiento & purificación
6.
Int J Food Microbiol ; 306: 108269, 2019 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-31330452

RESUMEN

Salmonella enterica serovar Enteritidis strain SE86 has been associated with several foodborne diseases occurring in Southern Brazil, becoming and important causative agent of human salmonellosis. In this work, the complete genome of the bacterium Salmonella Enteritidis SE86 was sequenced using the Illumina MiSeq platform. An in silico analysis of the SE86 genome was performed in order to compare it with different Salmonella strains as well as to investigate the presence of stress-resistance and virulence genes. This strain showed a variety of genes that can be involved in antimicrobial and biocide resistance, acid and thermal resistance as well as virulence and adhesion. These genetic features could explain its increased resistance and the prevalence of this strain in foodborne outbreaks in Southern Brazil.


Asunto(s)
Antibacterianos/farmacología , Intoxicación Alimentaria por Salmonella/epidemiología , Salmonella enteritidis , Brasil/epidemiología , Brotes de Enfermedades , Genoma Bacteriano/genética , Humanos , Pruebas de Sensibilidad Microbiana , Intoxicación Alimentaria por Salmonella/microbiología , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/genética , Salmonella enteritidis/patogenicidad , Virulencia/genética , Factores de Virulencia/genética
7.
Artículo en Inglés | MEDLINE | ID: mdl-31214517

RESUMEN

Non-typhoidal Salmonella (NTS) strains are Gram negative bacterial pathogens that are associated with foodborne illness worldwide. During the process of infection, Salmonella uses two molecular injectisomes known as Type 3 Secretion Systems (T3SS) to secrete virulence factors that are encoded by Salmonella Pathogenicity Island-1 (SPI-1) and SPI-2 into host cells. These secretion systems play a major role in virulence, as shown in various animal models, but little is known about their role in human infections. In Saudi Arabia, NTS strains frequently cause human infections but data regarding these pathogenic strains is fairly limited. The aim of this study was to characterize Salmonella human clinical isolates in Riyadh, Saudi Arabia, by determining their serotype, testing for the presence of SPI-1 and SPI-2 genes and to determine the antibiotic resistance profiles of these strains. Using the rapid Check and Trace Salmonella ™ (CTS) system our results demonstrate that S. Enteritidis and S. Typhimurium were the predominant serovars, followed by S. Livingstone, S. Kentucky and S. Poona among a list of 36 serovars reported for the first time in the country. In addition, SPI-1 genes were detected in 99% of the isolates, while the sifA gene (SPI-2) was not detected in 13.5% of the isolates. These results suggest that both the SPI-1 and SPI-2 virulence determinants are important for human infection. Moreover, we report the presence of a Multi-Drug (MDR) carbapenem resistant S. Kentucky isolate harboring the bla OXA-48 gene not reported previously in Saudi Arabia.


Asunto(s)
Proteínas Bacterianas/aislamiento & purificación , Proteínas de la Membrana/aislamiento & purificación , Salmonella enteritidis/aislamiento & purificación , Salmonella typhimurium/aislamiento & purificación , Serogrupo , Fiebre Tifoidea/microbiología , Factores de Virulencia/genética , Animales , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Carbapenémicos/farmacología , Modelos Animales de Enfermedad , Farmacorresistencia Bacteriana Múltiple , Genoma Bacteriano , Genotipo , Humanos , Proteínas de la Membrana/genética , Salmonella enteritidis/clasificación , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/genética , Salmonella typhimurium/clasificación , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/genética , Arabia Saudita/epidemiología , Serotipificación , Sistemas de Secreción Tipo III/genética , Sistemas de Secreción Tipo III/aislamiento & purificación , Virulencia , beta-Lactamasas/genética
8.
PLoS Negl Trop Dis ; 13(6): e0007485, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-31220112

RESUMEN

BACKGROUND: Salmonella enterica serovar Enteritidis is a cause of both poultry- and egg-associated enterocolitis globally and bloodstream-invasive nontyphoidal Salmonella (iNTS) disease in sub-Saharan Africa (sSA). Distinct, multi-drug resistant genotypes associated with iNTS disease in sSA have recently been described, often requiring treatment with fluoroquinolone antibiotics. In industrialised countries, antimicrobial use in poultry production has led to frequent fluoroquinolone resistance amongst globally prevalent enterocolitis-associated lineages. METHODOLOGY/PRINCIPAL FINDINGS: Twenty seven S. Enteritidis isolates from patients with iNTS disease and two poultry isolates, collected between 2007 and 2015 in the Ashanti region of Ghana, were whole-genome sequenced. These isolates, notable for a high rate of diminished ciprofloxacin susceptibility (DCS), were placed in the phyletic context of 1,067 sequences from the Public Health England (PHE) S. Enteritidis genome database to understand whether DCS was associated with African or globally-circulating clades of S. Enteritidis. Analysis showed four of the major S. Enteritidis clades were represented, two global and two African. All thirteen DCS isolates, containing a single gyrA mutation at codon 87, belonged to a global PT4-like clade responsible for epidemics of poultry-associated enterocolitis. Apart from two DCS isolates, which clustered with PHE isolates associated with travel to Spain and Brazil, the remaining DCS isolates, including one poultry isolate, belonged to two monophyletic clusters in which gyrA 87 mutations appear to have developed within the region. CONCLUSIONS/SIGNIFICANCE: Extensive phylogenetic diversity is evident amongst iNTS disease-associated S. Enteritidis in Ghana. Antimicrobial resistance profiles differed by clade, highlighting the challenges of devising empirical sepsis guidelines. The detection of fluoroquinolone resistance in phyletically-related poultry and human isolates is of major concern and surveillance and control measures within the region's burgeoning poultry industry are required to protect a human population at high risk of iNTS disease.


Asunto(s)
Antibacterianos/farmacología , Enfermedades Transmisibles Emergentes/epidemiología , Fluoroquinolonas/farmacología , Salmonelosis Animal/epidemiología , Infecciones por Salmonella/epidemiología , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/aislamiento & purificación , Adolescente , Animales , Niño , Preescolar , Enfermedades Transmisibles Emergentes/microbiología , Enfermedades Transmisibles Emergentes/veterinaria , Enterocolitis/epidemiología , Enterocolitis/microbiología , Enterocolitis/veterinaria , Femenino , Variación Genética , Genotipo , Ghana/epidemiología , Humanos , Lactante , Masculino , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Filogenia , Aves de Corral , Infecciones por Salmonella/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/clasificación , Salmonella enteritidis/genética , Secuenciación Completa del Genoma
9.
Microb Drug Resist ; 25(8): 1191-1198, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31120391

RESUMEN

Objectives: The primary aim of this study was to investigate the presence of antibiotic resistance genes (ARGs) and plasmid replicon types for 75 multidrug-resistant (MDR) Salmonella Enteritidis isolates from children with gastroenteritis. We also evaluated the association among biofilm formation, in vitro invasion capacity, and antibiotic resistance phenotypes. Materials and Methods: Twenty-two ARGs and 18 different plasmid incompatibility types were investigated using polymerase chain reaction (PCR) and DNA sequencing. In vitro invasion capacity of S. Enteritidis isolates possessing different antibiotic resistance patterns was assessed using the Caco2 human intestinal epithelial cell line and biofilm formation was performed in a 96-well polystyrene well format using crystal violet detection. Results: The presence of plasmid-mediated quinolone resistance genes and ß-lactamase genes was established using PCR amplification. All the tested S. Enteritidis isolates that were fluoroquinolone resistant possessed gyrA mutations and 50% also possessed mutations in parC. MDR S. Enteritidis isolates containing three (29/75) or four (21/75) plasmid replicon types were predominant and 71/75 carried both FIIs and FIC replicon-type plasmids. MDR isolates were strong or moderate biofilm producers and a significant positive association (p < 0.05) between antibiotic resistance and biomass of biofilms was observed in the strains assayed. A ceftiofur-resistant strain was significantly more invasive (p < 0.01) than the other isolates. Conclusions: We observed a high incidence of ARGs and diversity of plasmids in S. Enteritidis isolates from children. Biofilm formation and invasion capacity highlight a significant hazard to public health.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Farmacorresistencia Bacteriana Múltiple/genética , Gastroenteritis/microbiología , Plásmidos/genética , Infecciones por Salmonella/microbiología , Salmonella enteritidis/crecimiento & desarrollo , Salmonella enteritidis/genética , Antibacterianos/uso terapéutico , Biopelículas/efectos de los fármacos , Células CACO-2 , Línea Celular Tumoral , Niño , Células Epiteliales/microbiología , Gastroenteritis/tratamiento farmacológico , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Quinolonas/uso terapéutico , Infecciones por Salmonella/tratamiento farmacológico , Salmonella enteritidis/efectos de los fármacos , beta-Lactamasas/genética
10.
Poult Sci ; 98(7): 2948-2963, 2019 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-30953073

RESUMEN

Chickens are the reservoir host of Salmonella Enteritidis. Salmonella Enteritidis colonizes the gastro-intestinal tract of chickens and replicates within macrophages without causing clinically discernable illness. Persistence of S. Enteritidis in the hostile environments of intestinal tract and macrophages allows it to disseminate extra-intestinally to liver, spleen, and reproductive tract. Extra-intestinal dissemination into reproductive tract leads to contamination of internal contents of eggs, which is a major risk factor for human infection. Understanding the genes that contribute to S. Enteritidis persistence in the chicken host is central to elucidate the genetic basis of the unique pathobiology of this public health pathogen. The aim of this study was to identify a succinct set of genes associated with infection-relevant in vitro environments to provide a rational foundation for subsequent biologically-relevant research. We used in silico prediction of gene expression and RNA-seq technology to identify a core set of 73 S. Enteritidis genes that are consistently highly expressed in multiple S. Enteritidis strains cultured at avian physiologic temperature under conditions that represent intestinal and intracellular environments. These common highly expressed (CHX) genes encode proteins involved in bacterial metabolism, protein synthesis, cell-envelope biogenesis, stress response, and a few proteins with uncharacterized functions. Further studies are needed to dissect the contribution of these CHX genes to the pathobiology of S. Enteritidis in the avian host. Several of the CHX genes could serve as promising targets for studies towards the development of immunoprophylactic and novel therapeutic strategies to prevent colonization of chickens and their environment with S. Enteritidis.


Asunto(s)
Perfilación de la Expresión Génica , Expresión Génica , Salmonella enteritidis/genética , Animales , Proteínas Bacterianas/genética , Pollos , Simulación por Computador , Salmonelosis Animal/genética , Salmonella enteritidis/metabolismo
11.
J Appl Microbiol ; 127(1): 262-273, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31002451

RESUMEN

AIMS: The aim of this study was to develop a multiplex touchdown PCR (multiplex TD-PCR) for rapid and simultaneous detection of four major foodborne pathogens to avoid mispriming and unwanted production during gene amplification. Touchdown PCR is the modified form of standard PCR, which enhances specificity, sensitivity. METHODS AND RESULTS: For this reason, a multiplex TD-PCR assay with a pre-enrichment step was developed to detect four foodborne pathogens namely Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica serovar Enteritidis in pure culture and raw milk samples. The results showed that this protocol can eliminate the unwanted band or reduce significantly. The detection sensitivity of the single and multiplex TD-PCR was one cell per ml in pure culture. Furthermore, the detection limit of multiplex TD-PCR was one cell per 25 ml for artificially contaminated raw milk. We obtained similar results for detection of aforementioned pathogens in raw milk, after comparing the multiplex TD-PCR method with the traditional culture, except in one or two samples. CONCLUSIONS: Hence, the proposed multiplex TD-PCR method could be confirmed as an effective way for rapid optimization of PCR reactions to increase specificity, sensitivity during gene amplification. SIGNIFICANCE AND IMPACT OF THE STUDY: Hence, due to its simplicity, cost-effectiveness and being time-saving, it seems that this method is reasonable and economical for rapid optimization of PCR reactions.


Asunto(s)
Bacterias/aislamiento & purificación , Microbiología de Alimentos/métodos , Leche/microbiología , Reacción en Cadena de la Polimerasa Multiplex , Animales , Bacterias/genética , Escherichia coli O157/genética , Escherichia coli O157/aislamiento & purificación , Listeria monocytogenes/genética , Listeria monocytogenes/aislamiento & purificación , Salmonella enteritidis/genética , Salmonella enteritidis/aislamiento & purificación , Sensibilidad y Especificidad , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación
12.
Microb Pathog ; 129: 118-124, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30738177

RESUMEN

For detection and isolation of Salmonella enterica, 650 meat and tissue samples were processed using Rappaport-Vassiliadis Enrichment broth and Salmonella Chromogenic agar followed by confirmation through specific antisera and polymerase chain reaction (PCR) targeting their Specific Serovar Genomic Regions (SSGRS). Isolates were tested for 15 antibiotics (CRO, AMX, GEN, STR, TET, CHL, CLR, LVX, OFX, GAT, CIP, SXT, AMP, LIN and AZM) according to the disc diffusion method and antimicrobial resistant genes (tet(A), tet(B), tet(C), strA/strB, aadA, aac(3)IV), aadB, sul1, sul2 and sul3, blaCMY-2, blaTEM and blaSHV) using PCR. The overall prevalence of Salmonella enterica was 12%, being higher in markets (15%) as compared to poultry farms (37.2%). The MPN of all positive meat and tissue samples was found 3.6 MPN/gram (0.17-18). A total of 234 isolates were obtained, serovar Typimurium (139) and Enteridits (95) were the most prevalent. Antimicrobial resistance patterns were different in different serovars according to origin of Salmonella isolates. The overall isolates were highly resistant for LIN (93.1%, 218/234) followed by AMX (80%, 187/234), AMP (74.3%, 174/234), TET (64.5%, 151/234) and STR (64.5%, 151/234). Overall, the most common ARG was blaTEM (76%, 178/234), followed by blaSHV (71.7%, 168/234), tet(A) (64%, 151/234) and tet(B) (64%, 150/234), while the least ARG was aadB (7.2%, 17/234). Both Typimurium and Enteridits were tested in the Balb/C mice for pathogenicity. Both Typimurium and Enteridits were found to cause successful colonization, 100% morbidity but Enteriditis were found to cause 33% mortality.


Asunto(s)
Farmacorresistencia Bacteriana , Enfermedades de las Aves de Corral/microbiología , Productos Avícolas/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/aislamiento & purificación , Salmonella typhimurium/aislamiento & purificación , Animales , Antibacterianos/farmacología , Técnicas Bacteriológicas , Femenino , Genes Bacterianos , Ratones Endogámicos BALB C , Modelos Animales , Reacción en Cadena de la Polimerasa , Aves de Corral , Prevalencia , Salmonelosis Animal/epidemiología , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/genética , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/genética , Análisis de Supervivencia
13.
mSphere ; 4(1)2019 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-30760616

RESUMEN

The survival mechanism of Salmonella enterica serovar Enteritidis in antibacterial egg white is not fully understood. In our lab, an egg white-resistant strain, S. Enteritidis SJTUF 10978, was identified. Cell envelope damage and osmotic stress response (separation of cell wall and inner membrane as well as cytoplasmic shrinkage) of this strain surviving in egg white were identified through microscopic observation. RNA-Seq analysis of the transcriptome of Salmonella survival in egg white showed that a considerable number of genes involved in DNA damage repair, alkaline pH adaptation, osmotic stress adaptation, envelope damage repair, Salmonella pathogenicity island 2 (SPI-2), iron absorption, and biotin synthesis were significantly upregulated (fold change ≥ 2) in egg white, indicating that these pathways or genes might be critical for bacterial survival. RNA-Seq results were confirmed by qRT-PCR, and the survival analysis of six gene deletion mutants confirmed their importance in the survival of bacteria in egg white. The importance of alkaline pH adaptation and envelope damage repair for Salmonella to survive in egg white were further confirmed by analysis of nhaA, cpxR, waaH, and eco deletion mutants. According to the RNA-Seq results, we propose that alkaline pH adaptation might be the cause of bacterial osmotic stress phenotype and that the synergistic effect between alkaline pH and other inhibitory factors can enhance the bacteriostatic effect of egg white. Moreover, cpxR and sigE were recognized as the central regulators that coordinate bacterial metabolism to adapt to envelope damage and alkaline pH.IMPORTANCE Salmonella enterica serovar Enteritidis is a major foodborne pathogen that causes salmonellosis mainly through contaminated chicken eggs or egg products and has been a worldwide public health threat since 1980. Frequent outbreaks of this serotype through eggs correlate significantly with its exceptional survival ability in the antibacterial egg white. Research on the survival mechanism of S. Enteritidis in egg white will help to further understand the complex and highly effective antibacterial mechanisms of egg white and lay the foundation for the development of safe and effective vaccines to prevent egg contamination by this Salmonella serotype. Key pathways and genes that were previously overlooked under bactericidal conditions were characterized as being induced in egg white, and synergistic effects between different antimicrobial factors appear to exist according to the gene expression changes. Our work provides new insights into the survival mechanism of S. Enteritidis in egg white.


Asunto(s)
Clara de Huevo/microbiología , Perfilación de la Expresión Génica , Viabilidad Microbiana , Salmonella enteritidis/genética , Animales , Proteínas Bacterianas/genética , Pollos , Secuenciación de Nucleótidos de Alto Rendimiento , Concentración de Iones de Hidrógeno , Redes y Vías Metabólicas , Mutación , Presión Osmótica , Fenotipo , Salmonella enteritidis/patogenicidad , Análisis de Secuencia de ARN , Factor sigma/genética
14.
EcoSal Plus ; 8(2)2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30657108

RESUMEN

Nontyphoidal salmonellae (NTS) are a major cause of invasive (iNTS) disease in sub-Saharan Africa, manifesting as bacteremia and meningitis. Available epidemiological data indicate that iNTS disease is endemic in much of the region. Antimicrobial resistance is common and case fatality rates are high. There are well-characterized clinical associations with iNTS disease, including young age, HIV infection, malaria, malnutrition, anemia, and sickle cell disease. However, the clinical presentation of iNTS disease is often with fever alone, so clinical diagnosis is impossible without blood culture confirmation. No vaccine is currently available, making this a priority area for global health research. Over the past ten years, it has emerged that iNTS disease in Africa is caused by distinct pathovars of Salmonella Typhimurium, belonging to sequence type ST313, and Salmonella Enteritidis. These are characterized by genome degradation and appear to be adapting to an invasive lifestyle. Investigation of rare patients with primary immunodeficiencies has suggested a key role for interferon gamma-mediated immunity in host defense against NTS. This concept has been supported by recent population-based host genetic studies in African children. In contrast, immunoepidemiological studies from Africa indicate an important role for antibody for protective immunity, supporting the development of antibody-inducing vaccines against iNTS disease. With candidate O-antigen-based vaccines due to enter clinical trials in the near future, research efforts should focus on understanding the relative contributions of antibody and cell-mediated immunity to protection against iNTS disease in humans.


Asunto(s)
Infecciones por Salmonella/complicaciones , Infecciones por Salmonella/epidemiología , Salmonella enteritidis/patogenicidad , Salmonella typhimurium/patogenicidad , África del Sur del Sahara/epidemiología , Bacteriemia/epidemiología , Costo de Enfermedad , Humanos , Meningitis Bacterianas/epidemiología , Factores de Riesgo , Salmonella enteritidis/genética , Salmonella typhimurium/genética
15.
Poult Sci ; 98(5): 2281-2289, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-30624709

RESUMEN

Salmonella Enteritidis has developed the potential to contaminate eggs by surviving in the antimicrobial environment of the hen's egg white. This has led to a worldwide pandemic of foodborne salmonellosis infections in humans due to the consumption of contaminated eggs and egg-derived products. The molecular mechanisms of Salmonella Enteritidis egg white survival are not fully clear. Using in vivo expression technology and promoter-reporter fusions we showed that the promoter of the tolC gene, encoding the TolC outer membrane channel that is used by multidrug efflux pumps to export harmful molecules and to secrete bacterial products, is activated by egg white at the chicken body temperature. Using a Salmonella Enteritidis tolC deletion mutant we showed that TolC has an important role in egg white survival. Chromatographic separation techniques and subsequent testing of antimicrobial activities of separated egg white fractions led to the identification of ovotransferrin as the egg white antimicrobial factor which is capable of inhibiting growth of a tolC deletion strain but not the wild type strain. We provide evidence that TolC protects Salmonella Enteritidis against ovotransferrin-mediated growth inhibition in egg white.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa/genética , Pollos , Clara de Huevo/microbiología , Enfermedades de las Aves de Corral/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/genética , Animales , Proteínas de la Membrana Bacteriana Externa/metabolismo , Secuencia de Bases , Salmonella enteritidis/fisiología , Eliminación de Secuencia
16.
Microb Drug Resist ; 25(1): 133-142, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30113248

RESUMEN

The zoonotic serovars of Salmonella enterica particularly Typhimurium and Enteritidis pose a continuous global threat to poultry industry and public health. We report the prevalence of Salmonella Typhimurium and Salmonella Enteritidis serovars in local poultry, phenotypic antimicrobial resistance profiling, and molecular detection of antimicrobial resistance and virulence genes. A total of 340 clinical samples were collected and 239 carried Salmonella, which were identified by genus-specific PCR (invA gene) and by matrix-assisted laser desorption/ionization time-of-flight. The 68 and 22 isolates were confirmed as Salmonella Typhimurium (stm gene) and Salmonella Enteritidis (sdfI gene) respectively. Pulsed-field gel electrophoresis (PFGE) revealed 27 and 9 PFGE types of Salmonella Typhimurium and Salmonella Enteritidis respectively. Among 24 antimicrobials tested, highest resistance was observed against pefloxacin while highest susceptibility was found for ertapenem in Salmonella Typhimurium and aztreonam in Salmonella Enteritidis. All isolates were found multiple drug resistant, 98.8% as motile and 8.8% as extended spectrum beta lactamase producers. Most prevalent resistance gene in Salmonella Typhimurium was parE (69.1%) while in Salmonella Enteritidis blaTEM-1 (72.7%). High prevalence of SopE gene in Salmonella Typhimurium (91.1%) and Salmonella Enteritidis (81.8%) indicated their zoonotic potential. The study is first of its kind from this region and highlights the emerging trends of antimicrobial resistance of global concern.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Salmonella enterica/genética , Salmonella enteritidis/genética , Salmonella typhimurium/genética , Virulencia/genética , Animales , Antibacterianos/farmacología , Granjas , Pruebas de Sensibilidad Microbiana/métodos , Pakistán , Aves de Corral , Enfermedades de las Aves de Corral/tratamiento farmacológico , Enfermedades de las Aves de Corral/microbiología , Salmonelosis Animal/tratamiento farmacológico , Salmonelosis Animal/microbiología , Salmonella enterica/efectos de los fármacos , Salmonella enteritidis/efectos de los fármacos , Salmonella typhimurium/efectos de los fármacos
17.
Microb Pathog ; 126: 357-362, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30347261

RESUMEN

Infection with Salmonella Enteritidis (SE) is one of the main causes for food- and water-borne diseases, and is a major concern to public health for both humans and animals worldwide. Some fimbrial antigens expressed by SE strains have been described and characterized, containing SEF14, SEF17, SEF21, long polar fimbriae and plasmid-encoded fimbriae, they play a role in bacterial survival in the host or external environment. However, their functions remain to be well elucidated, with the initial attachment and binding for fimbriae-mediated SE infections only minimally understood. Meanwhile, host-pathogen interactions provide insights into receptor modulation of the host innate immune system. Therefore, to well understand the pathogenicity of SE bacteria and to comprehend the host response to infection, the host cell-SE interactions need to be characterized. This review describes SE fimbriae receptors with an emphasis on the interaction between the receptor and SE fimbriae.


Asunto(s)
Proteínas Fimbrias/metabolismo , Fimbrias Bacterianas/metabolismo , Receptores Inmunológicos , Infecciones por Salmonella/inmunología , Salmonella enteritidis/metabolismo , Antígenos Bacterianos/genética , Antígenos Bacterianos/metabolismo , Adhesión Bacteriana/fisiología , Proteínas Fimbrias/genética , Fimbrias Bacterianas/genética , Interacciones Huésped-Patógeno/inmunología , Inmunidad , Inmunidad Innata , Familia de Multigenes , Salmonella enteritidis/genética
18.
Can J Microbiol ; 65(2): 162-173, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30395482

RESUMEN

A real-time PCR (qPCR) regimen, using up to six genetic targets, was developed to rapidly detect Salmonella and in particular identify Salmonella Enteritidis. The test regimen was first evaluated using a reference culture collection of Salmonella to confirm the appropriateness of the selected targets, which included up to three genetic markers for discrimination of Salmonella Enteritidis from other Salmonella serovars commonly found in poultry facilities. The qPCR procedure was then compared with culture methods used to detect Salmonella using a collection of enrichment broths previously generated from 239 environmental samples collected from a large number of hatchery facilities across Canada over several years. The qPCR regimen facilitated specific detection of Salmonella Enteritidis, and on a sample basis, it showed excellent agreement with the culture methods. Moreover, in many cases, qPCR detected Salmonella earlier in the culture process than did the culture method. Application of this method will significantly shorten test times and allow more timely identification of infected poultry premises, thereby improving present programmes aimed at controlling Salmonella Enteritidis at the environmental source.


Asunto(s)
Aves de Corral/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Salmonella enteritidis/aislamiento & purificación , Animales , Salmonella enteritidis/genética , Serogrupo
19.
Infect Immun ; 87(1)2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30396895

RESUMEN

Salmonella enterica serovar Enteritidis is a common cause of foodborne illness in the United States. The bacterium can be transmitted to humans via contaminated chicken meat and eggs, and virulence in humans requires type III secretion system 1 (TTSS-1), encoded on Salmonella pathogenicity island 1 (SPI-1). Chickens often carry S Enteritidis subclinically, obscuring the role of SPI-1 in facilitating bacterial colonization. To evaluate the role of SPI-1 in the infection of chicks by Salmonella, we created and utilized strains harboring a stable fluorescent reporter fusion designed to quantify SPI-1 expression within the intestinal tracts of animals. Using mutants unable to express TTSS-1, we demonstrated the important role of the secretion system in facilitating bacterial colonization. We further showed that coinoculation of an SPI-1 mutant with the wild-type strain increased the number of mutant organisms in intestinal tissue and contents, suggesting that the wild type rescues the mutant. Our results support the hypothesis that SPI-1 facilitates S Enteritidis colonization of the chicken and make SPI-1 an attractive target in preventing Salmonella carriage and colonization in chickens to reduce contamination of poultry meat and eggs by this foodborne pathogen.


Asunto(s)
Proteínas Bacterianas , Portador Sano/veterinaria , Perfilación de la Expresión Génica , Intestinos/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/crecimiento & desarrollo , Salmonella enteritidis/genética , Animales , Fusión Artificial Génica , Portador Sano/microbiología , Pollos , Femenino , Genes Reporteros , Proteínas Luminiscentes/análisis , Proteínas Luminiscentes/genética , Ratones Endogámicos C57BL , Proteínas Recombinantes de Fusión/análisis , Proteínas Recombinantes de Fusión/genética
20.
Microb Drug Resist ; 25(2): 219-226, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30328753

RESUMEN

Salmonella enterica serovar Enteritidis is the most common cause of human salmonellosis worldwide. In this study, all clinical isolates of Salmonella Enteritidis recovered between January 2008 and June 2014 in a Spanish region (491) were screened for antimicrobial drug resistance and the phage type (PT) was determined for a significant number (265). PT1, PT14b, PT56, PT6, PT4, and PT8 were the predominant PTs, accounting together for 82% of the isolates. A total of 38.3% of the isolates were susceptible to all antimicrobials tested, 46.4% and 6.1% isolates were resistant to nalidixic acid and ampicillin, respectively, and single isolates were resistant to two (ampicillin and nalidixic acid) or six (ampicillin, chloramphenicol, streptomycin, sulfonamides, tetracycline, and trimethoprim) agents. Nalidixic acid resistance was statistically associated with PT1 and PT14b (p < 0.05, 95% CI), and ampicillin resistance with PT6/PT6a (p < 0.05, 95% CI). All ampicillin-resistant isolates (30) carried a plasmid-encoded blaTEM-1. All except one harbored the virulence plasmid specific of Salmonella Enteritidis (IncFIIA + IncFIB; 28 isolates) or a blaTEM-1-positive variant herein (IncFIIA + IncFIB; 1 isolate). Five additional blaTEM-1 plasmids, of the ColE1, IncX, IncF, and IncI incompatibility groups, were identified. The IncI plasmid, found in the single multidrug-resistant isolate, carried the strAB and sul2 genes together with genes of the virulence plasmid, including the spv operon. The obtained results highlight the high diversity of blaTEM-1 plasmids conferring ampicillin resistance in Salmonella Enteritidis, and support clonal expansion as the main cause of nalidixic acid resistance in this serovar.


Asunto(s)
Resistencia a la Ampicilina/genética , Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Plásmidos/genética , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/genética , Tipificación de Bacteriófagos , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/genética , Pruebas de Sensibilidad Microbiana , Ácido Nalidíxico/farmacología , Factores de Virulencia/genética
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