Molecular and phylogenetic analyses of Salmonella Gallinarum trace the origin and diversification of recent outbreaks of fowl typhoid in poultry farms.

PubMed

De Carli, Silvia; Gräf, Tiago; Kipper, Diéssy; Lehmann, Fernanda Kieling Moreira; Zanetti, Nathalie; Siqueira, Franciele Maboni; Cibulski, Samuel; Fonseca, André Salvador Kazantzi; Ikuta, Nilo; Lunge, Vagner Ricardo

2017-12-01

Fowl typhoid (FT) and pullorum disease (PD) are two important poultry infections caused by Salmonella enterica subsp. enterica serotype Gallinarum (S. Gallinarum). S. Gallinarum strains are adapted to birds and classified into biovars Gallinarum (bvGA) and Pullorum (bvPU) as they are the causative agent of FT and PD, respectively. In Brazil, FT/PD outbreaks have been reported along the last 50 years, but there was a recent increase of FT field reports with the suspicion it could be due to virulence reversion of the attenuated live vaccine SG9R. In this study, we applied molecular biology assays and phylogenetic methods to detect and investigate S. Gallinarum isolates from commercial poultry flocks in order to understand the evolutionary history and origin of the recent FT outbreaks in Brazil. S. Gallinarum isolates were obtained from thirteen different poultry flocks with clinical signs of FT/PD from 2013 to 2015. These isolates were serotyped, tested with three specific PCR (for the detection of bvGA, bvPU and live vaccine strain SG9R) and submitted to sequencing of a variable genome region (ISR analysis). The complete genome of one bvGA strain (BR_RS12) was also compared to other S. Gallinarum complete genomes (including other two Brazilian ones: bvGA 287/91 and bvPU FCVA198). PCR detected all thirteen isolates as S. Gallinarum (eight bvGA and five bvPU), none positive for SG9R strain. ISR analysis revealed that all eight bvGA isolates showed exactly the same nucleotide sequences with 100% similarity to reference strains, while two patterns were observed for bvPU. Genome phylogeny demonstrated distinct clades for bvGA and bvPU, with the bvGA clade showing a clear subdivision including three genomes: SG9R vaccine, the respective SG9 parent strain and one SG9R revertant field isolate (MB4523). The evolutionary rate of the total S. Gallinarum genome was calculated at 6.15×10 -7 substitutions/site/year, with 2.8 observed substitutions per year per genome (1 SNP per

Salmonella infections

USDA-ARS?s Scientific Manuscript database

Infections of poultry with bacteria of the genus Salmonella can cause clinical disease, but are of greater current concern as agents of food-borne transmission of illness to humans. However, two nonmotile organisms, S. Pullorum and S. Gallinarum, are host-specific for avian species. Pullorum disease...

Molecular differentiation between Salmonella enterica subsp enterica serovar Pullorum and Salmonella enterica subsp enterica serovar Gallinarum

PubMed Central

Ribeiro, Simone Alves Mendes; de Paiva, Jaqueline Boldrin; Zotesso, Fábio; Lemos, Manoel Victor Franco; Berchieri Jánior, Ângelo

2009-01-01

S. Pullorum (SP) and S. Gallinarum (SG) are very similar. They are the agents of pullorum disease and fowl typhoid, respectively, and the two diseases are responsible for economic losses in poultry production. Although SP and SG are difficult to be differentiated in routine laboratory procedures, the ability to metabolize ornithine is a biochemical test that may be used to achieve this aim. While SP is able to decarboxylate this amino acid, SG is not. However, the isolation of strains showing atypical biochemical behavior has made this differentiation difficult. One of the genes associated with the metabolization of the amino acid ornithine is called speC, and is found in both serovars. The analysis of 21 SP and 15 SG strains by means of PCR did not enable the differentiation of the two serovars, because fragments produced were identical. However, after enzymatic treatment with restriction enzyme Eco RI, the band pattern of each serovar showed to be different, even in samples of atypical biochemical behavior. This fact enabled the standardization of the technique for a quick and safe differentiation of serovars Pullorum and Gallinarum. PMID:24031341

An outer membrane protein (porin) as an eliciting antigen for delayed-type hypersensitivity in murine salmonellosis.

PubMed Central

Udhayakumar, V; Muthukkaruppan, V R

1987-01-01

The porin, an outer membrane protein of Salmonella typhimurium, was found to be a suitable antigen for eliciting delayed-type hypersensitivity in mouse salmonellosis. Histological examination of the reaction site revealed that the porin was superior to other antigenic preparations in eliciting a typical delayed-type hypersensitivity reaction consisting of mononuclear cell infiltration without polymorphonuclear cell contamination. This study indicates the importance of using a suitable protein antigen from S. typhi for human application. Images PMID:3028963

Inactivation of Salmonella on Eggshells by Chlorine Dioxide Gas

PubMed Central

Yum, Bora; Yoon, Sung-Sik; Song, Kyoung-Ju; Kim, Jong-Rak

2016-01-01

Microbiological contamination of eggs should be prevented in the poultry industry, as poultry is one of the major reservoirs of human Salmonella. ClO2 gas has been reported to be an effective disinfectant in various industry fields, particularly the food industry. The aims of this study were to evaluate the antimicrobial effect of chlorine dioxide gas on two strains of Salmonella inoculated onto eggshells under various experimental conditions including concentrations, contact time, humidity, and percentage organic matter. As a result, it was shown that chlorine dioxide gas under wet conditions was more effective in inactivating Salmonella Enteritidis and Salmonella Gallinarum compared to that under dry conditions independently of the presence of organic matter (yeast extract). Under wet conditions, a greater than 4 log reduction in bacterial populations was achieved after 30 min of exposure to ClO2 each at 20 ppm, 40 ppm, and 80 ppm against S. Enteritidis; 40 ppm and 80 ppm against S. Gallinarum. These results suggest that chlorine dioxide gas is an effective agent for controlling Salmonella, the most prevalent contaminant in the egg industry. PMID:27499670

The enhanced immune responses induced by Salmonella enteritidis ghosts loaded with Neisseria gonorrhoeae porB against Salmonella in mice.

PubMed

Jiao, Hongmei; Yang, Hui; Zhao, Dan; He, Li; Chen, Jin; Li, Guocai

2016-11-01

Human health has been seriously endangered by highly prevalent salmonellosis and multidrug-resistant Salmonella strains. Current vaccines suffer from variable immune-protective effects, so more effective ones are needed to control Salmonella infection : Bacterial ghosts have been produced by the expression of lysis gene E from bacteriophage PhiX174 and can be filled with considerable exogenous substances such as DNA or drugs as a novel platform. In this study, Salmonella enteritidis (SE) ghosts were developed and loaded with Neisseria gonorrhoeae porin B (porB) to construct a novel inactive vaccine. Our new studies show that SE ghosts loaded with porB displayed increased production of pro-inflammatory cytokines (IL-1β, IL-6, IL-10 and IL-12p70) in bone marrow-derived dendritic cells (BMDCs), and elicited significantly higher specific systemic and mucosal immune responses to Salmonella than SE ghosts alone. In addition, the novel porB-loaded ghosts conferred higher protective effects on virulent Salmonella challenge. For the first time, we demonstrate that N. gonorrhoeae porB, as a novel adjuvant, can increase the immunogenicity of SE ghosts. Our studies suggested that Salmonella enteritidis ghosts loaded with Neisseria gonorrhoeae porin B might be a useful mucosal Salmonella vaccine candidate for practical use in the future. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Improved antimicrobial activity of Pediococcus acidilactici against Salmonella Gallinarum by UV mutagenesis and genome shuffling.

PubMed

Han, Geon Goo; Song, Ahn Ah; Kim, Eun Bae; Yoon, Seong-Hyun; Bok, Jin-Duck; Cho, Chong-Su; Kil, Dong Yong; Kang, Sang-Kee; Choi, Yun-Jaie

2017-07-01

Pediococcus acidilactici is a widely used probiotic, and Salmonella enterica serovar Gallinarum (SG) is a significant pathogen in the poultry industry. In this study, we improved the antimicrobial activity of P. acidilactici against SG using UV mutation and genome shuffling (GS). To improve antimicrobial activity against SG, UV mutagenesis was performed against wild-type P. acidilactici (WT), and five mutants showed improved antimicrobial activity. To further improve antimicrobial activity, GS was performed on five UV mutants. Following GS, four mutants showed improved antimicrobial activity compared with the UV mutants and WT. The antimicrobial activity of GS1 was highest among the mutants; however, the activity was reduced when the culture supernatant was treated with proteinase K, suggesting that the improved antimicrobial activity is due to a proteinous substance such as bacteriocin. To validate the activity of GS1 in vivo, we designed multi-species probiotics and performed broiler feeding experiments. Groups consisted of no treatment (NC), avilamycin-treated (PC), probiotic group 1 containing WT (T1), and probiotic group 2 containing GS1 (T2). In broiler feeding experiments, coliform bacteria were significantly reduced in T2 compared with NC, PC, and T1. The cecal microbiota was modulated and pathogenic bacteria were reduced by GS1 oral administration. In this study, GS1 showed improved antimicrobial activity against SG in vitro and reduced pathogenic bacteria in a broiler feeding experiment. These results suggest that GS1 can serve as an efficient probiotic, as an alternative to antibiotics in the poultry industry.

Cross-protection against Salmonella enteritidis infection in mice. III. Delayed hypersensitivity reaction and clearance of the challenge organism.

PubMed

Padmanaban, V D; Mittal, K R

1979-01-01

Mice were immunized with live vaccines and with live vaccines with complete adjuvant incorporating Salmonella enteritidis, Salmonella typhi-murium, Salmonella gallinarum or Salmonella pullorum. On the 21st day after vacination, the hypersensitivity reactions elicited by the mice to extracts of the challenge organism (S. enteritidis 5694 SMR) were assessed. The degree of delayed hypersensitivity reaction was compared with the level of protection induced by the vaccine. The role in protection of delayed hypersensitivity is discussed. Clearance of the challenge organism from the liver of previously vaccinated and unvaccinated mice was assessed quantitatively.

1/f-Noise of open bacterial porin channels.

PubMed

Wohnsland, F; Benz, R

1997-07-01

General diffusion pores and specific porin channels from outer membranes of gram-negative bacteria were reconstituted into lipid bilayer membranes. The current noise of the channels was investigated for the different porins in the open state and in the ligand-induced closed state using fast Fourier transformation. The open channel noise exhibited 1/f-noise for frequencies up to 200 Hz. The 1/f-noise was investigated using the Hooge formula (Hooge, Phys. Lett. 29A: 139-140 (1969)), and the Hooge parameter alpha was calculated for all bacterial porins used in this study. The 1/f-noise was in part caused by slow inactivation and activation of porin channels. However, when care was taken that during the noise measurement no opening or closing of porin channels occurred, the Hooge Parameter alpha was a meaningful number for a given channel. A linear relationship was observed between alpha and the single-channel conductance, g, of the different porins. This linear relation between single-channel conductance and the Hooge parameter alpha could be qualitatively explained by assuming that the passing of an ion through a bacterial porin channel is-to a certain extent-influenced by nonlinear effects between channel wall and passing ion.

Gram-negative trimeric porins have specific LPS binding sites that are essential for porin biogenesis

PubMed Central

Arunmanee, Wanatchaporn; Pathania, Monisha; Solovyova, Alexandra S.; Le Brun, Anton P.; Ridley, Helen; Baslé, Arnaud; van den Berg, Bert; Lakey, Jeremy H.

2016-01-01

The outer membrane (OM) of gram-negative bacteria is an unusual asymmetric bilayer with an external monolayer of lipopolysaccharide (LPS) and an inner layer of phospholipids. The LPS layer is rigid and stabilized by divalent cation cross-links between phosphate groups on the core oligosaccharide regions. This means that the OM is robust and highly impermeable to toxins and antibiotics. During their biogenesis, OM proteins (OMPs), which function as transporters and receptors, must integrate into this ordered monolayer while preserving its impermeability. Here we reveal the specific interactions between the trimeric porins of Enterobacteriaceae and LPS. Isolated porins form complexes with variable numbers of LPS molecules, which are stabilized by calcium ions. In earlier studies, two high-affinity sites were predicted to contain groups of positively charged side chains. Mutation of these residues led to the loss of LPS binding and, in one site, also prevented trimerization of the porin, explaining the previously observed effect of LPS mutants on porin folding. The high-resolution X-ray crystal structure of a trimeric porin–LPS complex not only helps to explain the mutagenesis results but also reveals more complex, subtle porin–LPS interactions and a bridging calcium ion. PMID:27493217

Crystallization and preliminary X-ray diffraction analysis of ScrY, a specific bacterial outer membrane porin.

PubMed

Forst, D; Schülein, K; Wacker, T; Diederichs, K; Kreutz, W; Benz, R; Welte, W

1993-01-05

The sucrose-specific outer membrane porin ScrY of Salmonella typhimurium was isolated from Escherichia coli K-12 strain KS 26 containing the plasmid pPSO112. The protein was purified to homogeneity by differential extraction of the cell envelope in the presence of the detergents sodium dodecyl sulfate and lauryl (dimethyl)-amine oxide (LDAO). The porin had apparent molecular weights of 58 kDa and 120 kDa for the monomer and for the trimer, respectively, on SDS/PAGE. The purified trimers were crystallized using poly(ethylene glycol) 2000 and the detergents octylglucoside (OG) and hexyl-(dimethyl)-amine oxide (C6DAO). X-ray diffraction of the crystals showed reflections to 2.3 A. The space group of the crystals was R3 and the lattice constants of the hexagonal axes were a = b = 112.85 A and c = 149.9 A. The crystal volume per unit of protein molecular weight was 3.47 A3/Da.

Use of Intragenic Sequence Ribotyping (ISR) for serotyping Salmonella obtained from poultry and their environment

USDA-ARS?s Scientific Manuscript database

BACKGROUND: The dkgB-linked ribosomal region of Salmonella enterica flanking a 5S gene shows genetic heterogeneity that distinguishes closely related serovars such as Enteritidis, Dublin, Gallinarum and Pullorum (Morales et al, 2006). We wanted to know how sequence-based ISR compared to the traditio...

Gastrointestinal microbial ecology and the safety of our food supply as related to Salmonella.

PubMed

Callaway, T R; Edrington, T S; Anderson, R C; Byrd, J A; Nisbet, D J

2008-04-01

Salmonella causes an estimated 1.3 million human foodborne illnesses and more than 500 deaths each year in the United States, representing an annual estimated cost to the economy of approximately $2.4 billion. Salmonella enterica comprises more than 2,500 serotypes. With this genetic and environmental diversity, serotypes are adapted to live in a variety of hosts, which may or may not manifest with clinical illness. Thus, Salmonella presents a multifaceted threat to food production and safety. Salmonella have been isolated from all food animals and can cause morbidity and mortality in swine, cattle, sheep, and poultry. The link between human salmonellosis and host animals is most clear in poultry. During the early part of the 20th century, a successful campaign was waged to eliminate fowl typhoid caused by Salmonella Gallinarum/Pullorum. Microbial ecology is much like macroecology; environmental niches are filled by adapted and specialized species. Elimination of S. Gallinarum cleared a niche in the on-farm and intestinal microbial ecology that was quickly exploited by Salmonella Enteritidis and other serotypes that live in other hosts, such as rodents. In the years since, human salmonellosis cases linked to poultry have increased to the point that uncooked chicken and eggs are regarded as toxic in the zeitgeist. Salmonellosis caused by poultry products have increased significantly in the past 5 yr, leading to a USDA Food Safety and Inspection Service "Salmonella Attack Plan" that aims to reduce the incidence of Salmonella in chickens below the current 19%. The prevalence of Salmonella in swine and cattle is lower, but still poses a threat to food safety and production efficiency. Thus, approaches to reducing Salmonella in animals must take into consideration that the microbial ecology of the animal is a critical factor that should be accounted for when designing intervention strategies. Use of competitive exclusion, sodium chlorate, vaccination, and bacteriophage

Presence of Salmonella Enteritidis and Salmonella Gallinarum in commercial laying hens diagnosed with Fowl Typhoid Disease in Colombia

USDA-ARS?s Scientific Manuscript database

: A severe outbreak of salmonellosis in commercial brown table egg layers first occurred in Colombia in 2006. From 2008 to 2012, 35 samples collected from commercial layers farms in the states of Cundinamarca, Santander, Bolivar and San Andres, were positive to Salmonella enterica. Salmonella (S) wa...

Porins Increase Copper Susceptibility of Mycobacterium tuberculosis

PubMed Central

Speer, Alexander; Rowland, Jennifer L.; Haeili, Mehri; Niederweis, Michael

2013-01-01

Copper resistance mechanisms are crucial for many pathogenic bacteria, including Mycobacterium tuberculosis, during infection because the innate immune system utilizes copper ions to kill bacterial intruders. Despite several studies detailing responses of mycobacteria to copper, the pathways by which copper ions cross the mycobacterial cell envelope are unknown. Deletion of porin genes in Mycobacterium smegmatis leads to a severe growth defect on trace copper medium but simultaneously increases tolerance for copper at elevated concentrations, indicating that porins mediate copper uptake across the outer membrane. Heterologous expression of the mycobacterial porin gene mspA reduced growth of M. tuberculosis in the presence of 2.5 μM copper by 40% and completely suppressed growth at 15 μM copper, while wild-type M. tuberculosis reached its normal cell density at that copper concentration. Moreover, the polyamine spermine, a known inhibitor of porin activity in Gram-negative bacteria, enhanced tolerance of M. tuberculosis for copper, suggesting that copper ions utilize endogenous outer membrane channel proteins of M. tuberculosis to gain access to interior cellular compartments. In summary, these findings highlight the outer membrane as the first barrier against copper ions and the role of porins in mediating copper uptake in M. smegmatis and M. tuberculosis. PMID:24013632

Safety, Protective Immunity, and DIVA Capability of a Rough Mutant Salmonella Pullorum Vaccine Candidate in Broilers.

PubMed

Guo, Rongxian; Jiao, Yang; Li, Zhuoyang; Zhu, Shanshan; Fei, Xiao; Geng, Shizhong; Pan, Zhiming; Chen, Xiang; Li, Qiuchun; Jiao, Xinan

2017-01-01

Salmonella enterica subsp. enterica serovar Gallinarum biovar Pullorum ( Salmonella Pullorum) is highly adapted to chickens causing an acute systemic disease that results in high mortality. Vaccination represents one approach for promoting animal health, food safety and reducing environmental persistence in Salmonella control. An important consideration is that Salmonella vaccination in poultry should not interfere with the salmonellosis monitoring program. This is the basis of the DIVA (Differentiation of Infected and Vaccinated Animals) program. In order to achieve this goal, waaL mutant was developed on a spiC mutant that was developed previously. The safety, efficacy, and DIVA features of this vaccine candidate ( Salmonella Pullorum Δ spiC Δ waaL ) were evaluated in broilers. Our results show that the truncated LPS in the vaccine strain has a differentiating use as both a bacteriological marker (rough phenotype) and also as a serological marker facilitating the differentiation between infected and vaccinated chickens. The rough mutant showed adequate safety being avirulent in the host chicks and showed increased sensitivity to environmental stresses. Single intramuscular immunization of day-old broiler chicks with the mutant confers ideal protection against lethal wild type challenge by significantly stimulating both humoral and cellular immune responses as well as reducing the colonization of the challenge strain. Significantly lower mean pathology scores were observed in the vaccination group compared to the control group. Additionally, the mutant strain generated cross-protection against challenge with the wild type Salmonella Gallinarum thereby improving survival and with the wild type Salmonella Enteritidis thereby reducing colonization. These results suggest that the double-mutant strain may be a safe, effective, and cross-protective vaccine against Salmonella infection in chicks while conforming to the requirements of the DIVA program.

Type 1 fimbriae are important factors limiting the dissemination and colonization of mice by Salmonella Enteritidis and contribute to the induction of intestinal inflammation during Salmonella invasion

PubMed Central

Kuźmińska-Bajor, Marta; Grzymajło, Krzysztof; Ugorski, Maciej

2015-01-01

We have recently shown that Salmonella Gallinarum type 1 fimbriae with endogenous mannose-resistant (MR) variant of the FimH protein increase systemic dissemination of S. Gallinarum and colonization of internal organs in comparison to the S. Gallinarum fimH knockout strain or the mutant expressing mannose-sensitive (MS) FimH variant from S. Enteritidis. Elaborating from these studies, we proposed that MS variants of FimH are advantageous in gastrointestinal infections, in contrast to MR FimH variants which decrease intestinal colonization and promote their systemic spreading. To support our hypothesis, we carried out in vivo studies using mice infected with wild-type S. Enteritidis and its fimH knockout strain (S. Enteritidis), which was characterized by significantly lower adhesion and invasiveness of murine ICE-1 intestinal cells. Using bioluminescence imaging, we observed that the loss of MS FimH adhesin correlates well with the highly increased colonization of mice by these bacteria. The appearance of the mutant strain was observed much earlier than wild-type Salmonella, and mice infected with 104–107 S. Enteritidis fimH::kan CFUs had significantly (P < 0.05) shorter infection-free time than animals inoculated with wild-type S. Enteritidis. Infections caused by non-typhoid Salmonella, such as S. Enteritidis, are associated with massive inflammation of the lamina propria and lymph nodes in the intestinal tract. Therefore, we evaluated the role of MS type 1 fimbriae in the induction of cytokine expression and secretion, using murine ICE-1 intestinal cells. We showed that the expression, as well as secretion, of Il-1b, Il-6, Il-10, and Il-12b was significantly higher in cells infected with wild-type S. Enteritidis compared to cells infected with the mutant strain. Based on our results, we propose that type 1 fimbriae may play an important role in the pathogenicity of S. Enteritidis and may contribute to an intestinal inflammatory response. PMID:25914682

Increased susceptibility to beta-lactam antibiotics and decreased porin content caused by envB mutations of Salmonella typhimurium.

PubMed Central

Oppezzo, O J; Avanzati, B; Antón, D N

1991-01-01

Isogenic derivatives carrying envB6, envB9, or envB+ alleles were obtained from a strain of Salmonella typhimurium that was partially resistant to mecillinam, a beta-lactam antibiotic specific for penicillin-binding protein 2 (PBP 2). Testing of the isogenic strains with several antibacterial agents demonstrated that envB mutations either increased resistance (mecillinam) or did not affect the response (imipemen) to beta-lactams that act primarily on PBP 2, while susceptibilities to beta-lactams that act on PBP 1B, PBP 3, or both were increased. Furthermore, the susceptibilities of envB strains to hydrophobic compounds such as rifampin, novobiocin, or chloramphenicol were not modified, even though their susceptibilities to deoxycholate and crystal violet were enhanced. Outer cell membranes of envB mutants presented a 50% reduction in protein content compared with that of the isogenic envB+ strains, and OmpF and OmpD porins were particularly affected by the reduction. No alteration in the amount or pattern of periplasmic proteins was noticed, and lipopolysaccharides from envB mutants appeared to be normal by sodium dodecyl sulfate-urea-polyacrylamide gel electrophoresis. By using derivatives that produced a plasmid-encoded beta-lactamase, it was demonstrated that envB cells are slightly less permeable to cephalothin than envB+ bacteria are. It is concluded that the high susceptibility of envB mutants to beta-lactams is due to the increased effectiveness of the antibiotics on PBP 1B, PBP 3, or both. Images PMID:1656857

Identification and Characterization of the Major Porin of Desulfovibrio vulgaris Hildenborough

DOE PAGES

Zeng, Lucy; Wooton, Etsuko; Stahl, David A.; ...

2017-09-05

Due in large part to their ability to facilitate the diffusion of a diverse range of solutes across the outer membrane (OM) of Gram-negative bacteria, the porins represent one of the most prominent and important bacterial membrane protein superfamilies. Notably, for the Gram-negative bacterium Desulfovibrio vulgaris Hildenborough, a model organism for studies of sulfate-reducing bacteria, no genes for porins have been identified or proposed in its annotated genome. Results from initial biochemical studies suggested that the product of the DVU0799 gene, which is one of the most abundant proteins of the D. vulgaris Hildenborough OM and purified as a homotrimericmore » complex, was a strong porin candidate. To investigate this possibility, this protein was further characterized biochemically and biophysically. Structural analyses via electron microscopy of negatively stained protein identified trimeric particles with stain-filled depressions and structural modeling suggested a β-barrel structure for the monomer, motifs common among the known porins. Functional studies were performed in which crude OM preparations or purified DVU0799 was reconstituted into proteoliposomes and the proteoliposomes were examined for permeability against a series of test solutes. The results obtained establish DVU0799 to be a pore-forming protein with permeability properties similar to those observed for classical bacterial porins, such as those of Escherichia coli. Taken together, these findings identify this highly abundant OM protein to be the major porin of D. vulgaris Hildenborough. Classification of DVU0799 in this model organism expands the database of functionally characterized porins and may also extend the range over which sequence analysis strategies can be used to identify porins in other bacterial genomes. Porins are membrane proteins that form transmembrane pores for the passive transport of small molecules across the outer membranes of Gram-negative bacteria. The present

Identification and Characterization of the Major Porin of Desulfovibrio vulgaris Hildenborough

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Lucy; Wooton, Etsuko; Stahl, David A.

Due in large part to their ability to facilitate the diffusion of a diverse range of solutes across the outer membrane (OM) of Gram-negative bacteria, the porins represent one of the most prominent and important bacterial membrane protein superfamilies. Notably, for the Gram-negative bacterium Desulfovibrio vulgaris Hildenborough, a model organism for studies of sulfate-reducing bacteria, no genes for porins have been identified or proposed in its annotated genome. Results from initial biochemical studies suggested that the product of the DVU0799 gene, which is one of the most abundant proteins of the D. vulgaris Hildenborough OM and purified as a homotrimericmore » complex, was a strong porin candidate. To investigate this possibility, this protein was further characterized biochemically and biophysically. Structural analyses via electron microscopy of negatively stained protein identified trimeric particles with stain-filled depressions and structural modeling suggested a β-barrel structure for the monomer, motifs common among the known porins. Functional studies were performed in which crude OM preparations or purified DVU0799 was reconstituted into proteoliposomes and the proteoliposomes were examined for permeability against a series of test solutes. The results obtained establish DVU0799 to be a pore-forming protein with permeability properties similar to those observed for classical bacterial porins, such as those of Escherichia coli. Taken together, these findings identify this highly abundant OM protein to be the major porin of D. vulgaris Hildenborough. Classification of DVU0799 in this model organism expands the database of functionally characterized porins and may also extend the range over which sequence analysis strategies can be used to identify porins in other bacterial genomes. Porins are membrane proteins that form transmembrane pores for the passive transport of small molecules across the outer membranes of Gram-negative bacteria. The present

Importance of Porins for Biocide Efficacy against Mycobacterium smegmatis▿

PubMed Central

Frenzel, Elrike; Schmidt, Stefan; Niederweis, Michael; Steinhauer, Katrin

2011-01-01

Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the deletion of Msp porins in isogenic mutants increased the resistance of Mycobacterium smegmatis to isothiazolinones (methylchloroisothiazolinone [MCI]/methylisothiazolinone [MI] and octylisothiazolinone [2-n-octyl-4-isothiazolin-3-one; OIT]), formaldehyde-releasing biocides {hexahydrotriazine [1,3,5-tris (2-hydroxyethyl)-hexahydrotriazine; HHT] and methylenbisoxazolidine [N,N′-methylene-bis-5-(methyloxazolidine); MBO]}, and the lipophilic biocides polyhexamethylene biguanide and octenidine dihydrochloride 2- to 16-fold. Furthermore, the susceptibility of the porin triple mutant against a complex disinfectant was decreased 8-fold compared to wild-type (wt) M. smegmatis. Efficacy testing in the quantitative suspension test EN 14348 revealed 100-fold improved survival of the porin mutant in the presence of this biocide. These findings underline the importance of porins for the susceptibility of M. smegmatis to biocides. PMID:21398489

Functional assay of Salmonella typhi OmpC using reconstituted large unilamellar vesicles: a general method for characterization of outer membrane proteins.

PubMed

Sundara Baalaji, N; Mathew, M K; Krishnaswamy, S

2006-10-01

The immunodominant trimeric beta-barrel outer membrane protein OmpC from Salmonella typhi, the causative agent of typhoid, has been functionally characterized here. The activity in the vesicle environment was studied in vitro using OmpC reconstituted into proteoliposomes. Passage of polysaccharides and polyethyleneglycols through OmpC has been examined to determine the permeability properties. The relative rate of neutral solute flux yields a radius of 1.1 nm for the S. typhi OmpC pore. This is almost double the pore size of Escherichia coli. This provides an example of large pore size present in the porins that form trimers as in the general bacterial porin family. The method used in this study provides a good membrane model for functional studies of porins.

PCR for the identification and differentiation of Histomonas meleagridis, Tetratrichomonas gallinarum and Blastocystis spp.

PubMed

Grabensteiner, E; Hess, M

2006-12-20

In the present investigation PCR assays were developed for the rapid detection and differentiation of two poultry flagellates: Histomonas meleagridis and Tetratrichomonas gallinarum as well as the protozoan microorganism: Blastocystis spp. The nucleotide sequences of the small subunit ribosomal RNAs were used for primer construction obtaining fragments which vary in size for each microorganism. The established PCRs were able to detect DNA obtained from one microorganism of T. gallinarum and Blastocystis spp. propagated in vitro, proving the high analytical sensitivity of the method. DNA isolated from 10 protozoa was sufficient to detect H. meleagridis. To assess specificity, each PCR assay was performed with DNA from either H. meleagridis and/or T. gallinarum and/or Blastocystis spp. as well as with DNA from several other protozoan parasites (Eimeria tenella, Toxoplasma gondii, Cryptosporidia spp., Trichomonas gallinae, Entamoeba invadens, Entamoeba ranarum), fungi (Aspergillus fumigatus, Candida albicans), bacteria (Staphylococcae, Streptococcae, E. coli, Clostridium perfringens, Camplyobacter jejuni, Proteus) and viruses (fowl adenovirus serotype 4, avian reovirus) as well as livers and caecal samples from turkeys and specified pathogen free (spf) chickens. No cross-reactions with any of these samples were observed with the primer sets for the detection of H. meleagridis and Blastocystis spp. The primers designed for the identification of T. gallinarum yielded a PCR product with DNA of Trichomonas gallinae that had the identical size as the amplicon obtained with DNA from T. gallinarum. However, no PCR products resulted from any of the other samples tested with these primers. Liver and caecal samples from turkeys and chickens from flocks with outbreaks of histomonosis also named as "histomoniasis" originating from geographically distinct regions were investigated with the established PCRs. This is also the first report about the detection of the nucleic acid of H

Porin Deficiency in Carbapenem-Resistant Enterobacter aerogenes Strains.

PubMed

Hao, Min; Ye, Meiping; Shen, Zhen; Hu, Fupin; Yang, Yang; Wu, Shi; Xu, Xiaogang; Zhu, Sihui; Qin, Xiaohua; Wang, Minggui

2018-03-13

The more frequent reports of carbapenem-resistant Enterobacteriaceae have raised the alarm for public health. Apart from the production of carbapenemases, deficiency (decreased or loss of expression) of outer membrane proteins (OMPs) has been proposed as a potentially important mechanism of carbapenem resistance. The aim of the present study was to evaluate the contribution of the major OMPs to carbapenem resistance in Enterobacter aerogenes (CREA) isolates and also investigate the role of small RNAs (sRNAs) in inducing porin-associated permeability defects. The differential expression of OMPs was analyzed in four clinical CREA isolates. omp35 and omp36 genes were further investigated by whole-genome sequencing, induction of meropenem resistance, sRNA overexpression, OMP complementation assays, and reverse transcription-quantitative PCR. All four isolates examined were deficient in omp35 and omp36. Functional restoration of these two genes confirmed their contribution to carbapenem resistance. The meropenem induction assay further revealed that porin deficiency plays a role in carbapenem resistance under antibiotic selection pressure. Single-point mutations in omp36 leading to premature stop codons were detected in two of the isolates. Elevated expression levels of the sRNAs micF and micC were detected in the other two porin-deficient isolates, which were predicted to be potential porin regulators from whole-genome sequencing. Overexpression of micF and micC downregulated the expression of Omp35 and Omp36, respectively. Porin deficiency plays an important role in carbapenem resistance among clinical E. aerogenes isolates under regulation of the sRNAs micC and micF. Furthermore, overexpression of micC and micF had a minor to no impact on carbapenem minimum inhibitory concentrations, and thus, the regulatory mechanism is likely to be complex.

How β-Lactam Antibiotics Enter Bacteria: A Dialogue with the Porins

PubMed Central

Molitor, Alexander; Bolla, Jean-Michel; Bessonov, Andrey N.; Winterhalter, Mathias; Pagès, Jean-Marie

2009-01-01

Background Multi-drug resistant (MDR) infections have become a major concern in hospitals worldwide. This study investigates membrane translocation, which is the first step required for drug action on internal bacterial targets. β-lactams, a major antibiotic class, use porins to pass through the outer membrane barrier of Gram-negative bacteria. Clinical reports have linked the MDR phenotype to altered membrane permeability including porin modification and efflux pump expression. Methodology/Principal Findings Here influx of β-lactams through the major Enterobacter aerogenes porin Omp36 is characterized. Conductance measurements through a single Omp36 trimer reconstituted into a planar lipid bilayer allowed us to count the passage of single β-lactam molecules. Statistical analysis of each transport event yielded the kinetic parameters of antibiotic travel through Omp36 and distinguishable translocation properties of β-lactams were quantified for ertapenem and cefepime. Expression of Omp36 in an otherwise porin-null bacterial strain is shown to confer increases in the killing rate of these antibiotics and in the corresponding bacterial susceptibility. Conclusions/Significance We propose the idea of a molecular “passport” that allows rapid transport of substrates through porins. Deciphering antibiotic translocation provides new insights for the design of novel drugs that may be highly effective at passing through the porin constriction zone. Such data may hold the key for the next generation of antibiotics capable of rapid intracellular accumulation to circumvent the further development MDR infections. PMID:19434239

Biophysical characterization of OprB, a glucose-inducible porin of Pseudomonas aeruginosa.

PubMed

Wylie, J L; Bernegger-Egli, C; O'Neil, J D; Worobec, E A

1993-10-01

OprB, a glucose-inducible porin of P. aeruginosa, was characterized by black lipid bilayer analysis and circular dichroism spectroscopy. Black lipid bilayer analysis of OprB revealed a single-channel conductance of 25 pS, the presence of a glucose binding site with a Ks for glucose of 380 +/- 40 mM, and the formation of channels with a strong selection for anions. Analysis of P. aeruginosa OprB circular dichroism spectra revealed a high beta sheet content (40%) which is within the range of that determined for other porins. Values obtained from black lipid bilayer analysis were compared to those previously obtained for OprB of P. putida [Saravolac et al. (1991). J. Bacteriol. 173, 4970-4976] and indicated extensive similarities in the single-channel conductance and glucose-binding properties of these two porins. Immunological and amino terminal sequence analysis revealed a high degree of homology. Of the first 14 amino terminal residues, 12 were identical. A major difference between the two porins was found in their ion selectivity. Whereas P. aeruginosa OprB is anion selective, P. putida OprB and other carbohydrate selective porins are known to be cation selective.

Putative Porin of Bradyrhizobium sp. (Lupinus) Bacteroids Induced by Glyphosate▿

PubMed Central

de María, Nuria; Guevara, Ángeles; Serra, M. Teresa; García-Luque, Isabel; González-Sama, Alfonso; de Lacoba, Mario García; de Felipe, M. Rosario; Fernández-Pascual, Mercedes

2007-01-01

Application of glyphosate (N-[phosphonomethyl] glycine) to Bradyrhizobium sp. (Lupinus)-nodulated lupin plants caused modifications in the protein pattern of bacteroids. The most significant change was the presence of a 44-kDa polypeptide in bacteroids from plants treated with the higher doses of glyphosate employed (5 and 10 mM). The polypeptide has been characterized by the amino acid sequencing of its N terminus and the isolation and nucleic acid sequencing of its encoding gene. It is putatively encoded by a single gene, and the protein has been identified as a putative porin. Protein modeling revealed the existence of several domains sharing similarity to different porins, such as a transmembrane beta-barrel. The protein has been designated BLpp, for Bradyrhizobium sp. (Lupinus) putative porin, and would be the first porin described in Bradyrhizobium sp. (Lupinus). In addition, a putative conserved domain of porins has been identified which consists of 87 amino acids, located in the BLpp sequence 30 amino acids downstream of the N-terminal region. In bacteroids, mRNA of the BLpp gene shows a basal constitutive expression that increases under glyphosate treatment, and the expression of the gene is seemingly regulated at the transcriptional level. By contrast, in free-living bacteria glyphosate treatment leads to an inhibition of BLpp mRNA accumulation, indicating a different effect of glyphosate on BLpp gene expression in bacteroids and free-living bacteria. The possible role of BLpp in a metabolite interchange between Bradyrhizobium and lupin is discussed. PMID:17557843

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

PubMed Central

Johnson, Timothy J.; Ricke, Steven C.; Nayak, Rajesh; Danzeisen, Jessica

2013-01-01

SUMMARY Enteric pathogens such as Salmonella enterica cause significant morbidity and mortality. S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. S. enterica serovars such as S. Typhi, S. Dublin, and S. Gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while S. Enteritidis and S. Typhimurium have broad host ranges. This review examines how S. enterica has evolved through adaptation to different host environments, especially as related to the chicken host, and continues to be an important human pathogen. Several factors impact host range, and these include the acquisition of genes via horizontal gene transfer with plasmids, transposons, and phages, which can potentially expand host range, and the loss of genes or their function, which would reduce the range of hosts that the organism can infect. S. Gallinarum, with a limited host range, has a large number of pseudogenes in its genome compared to broader-host-range serovars. S. enterica serovars such as S. Kentucky and S. Heidelberg also often have plasmids that may help them colonize poultry more efficiently. The ability to colonize different hosts also involves interactions with the host's immune system and commensal organisms that are present. Thus, the factors that impact the ability of Salmonella to colonize a particular host species, such as chickens, are complex and multifactorial, involving the host, the pathogen, and extrinsic pressures. It is the interplay of these factors which leads to the differences in host ranges that we observe today. PMID:24296573

Molecular characterization of a 40 kDa OmpC-like porin from Serratia marcescens.

PubMed

Hutsul, J A; Worobec, E

1994-02-01

An oligonucleotide that encodes the N-terminal portion of a 41 kDa porin of Serratia marcescens was used to probe S. marcescens UOC-51 genomic DNA. An 11 kb EcoRI fragment which hybridized with the oligonucleotide was subcloned into Escherichia coli, examined for expression, and sequenced. The product expressed by the cloned gene was 40 kDa. The nucleotide sequence has an ORF of 1.13 kb. When the deduced amino acid sequence was aligned and compared to other enterobacterial porins the cloned S. marcescens porin most closely resembled E. coli OmpC. Although we did not detect osmoregulation or thermoregulation of any porins in S. marcescens UOC-51, sequences analogous to the E. coli osmoregulator OmpR-binding regions are seen upstream to the cloned gene. We examined the regulation of the S. marcescens porin in E. coli and found that its expression increased in a high salt environment. A micF gene, whose transcriptional product functions to inhibit synthesis of OmpF by hybridizing with the ompF transcript, was also seen upstream of the S. marcescens ompC. An alignment with the E. coli micF gene revealed that the functional region of the S. marcescens micF gene is conserved. Based on the results obtained we have determined that S. marcescens UOC-51 produces a 40 kDa porin similar to the E. coli OmpC porin.

Influence of Culture Conditions on Expression of the 40-Kilodalton Porin Protein of Vibrio anguillarum Serotype O2

PubMed Central

Davey, Michelle L.; Hancock, Robert E. W.; Mutharia, Lucy M.

1998-01-01

Vibrio anguillarum serotype O2 strains express a 40-kDa outer membrane porin protein. Immunoblot analysis revealed that antigenic determinants of the V. anguillarum O2 40-kDa porin were conserved within bacterial species of the genus Vibrio. The relative amounts of the V. anguillarum O2 40-kDa porin were enhanced by growth of V. anguillarum O2 in CM9 medium containing 5 to 10% sucrose or 0.1 to 0.5 M NaCl. In contrast, the levels of the porin were significantly reduced when cells were grown at 37°C, and a novel 60-kDa protein was also observed. However, the osmolarity or ionic concentration of the growth medium did not influence expression of the 60-kDa protein. Growth in medium containing greater than 0.6 mM EDTA reduced production of the V. anguillarum O2 40-kDa porin and enhanced levels of a novel 19-kDa protein. Thus, expression of the V. anguillarum O2 40-kDa porin was osmoregulated and possibly coregulated by temperature. The N-terminal amino acid sequence of the V. anguillarum O2 40-kDa protein and the effect of environmental factors on the cellular levels of the porin suggested that the V. anguillarum O2 40-kDa porin was functionally similar to the OmpC porin of Escherichia coli. However, pore conductance assays revealed that the V. anguillarum O2 40-kDa porin was a general diffusion porin with a pore size in the range of that of the OmpF porin of E. coli. PMID:9435071

Isolation, characterization, and application of bacteriophages for Salmonella spp. biocontrol in pigs.

PubMed

Albino, Luiz A A; Rostagno, Marcos H; Húngaro, Humberto M; Mendonça, Regina C S

2014-08-01

Foodborne illness due to Salmonella-contaminated pork products is an important public health problem, causing significant economic losses worldwide. The use of bacteriophages is a potential intervention tool that has attracted interest for the control of foodborne pathogens. The objective of this study was to detect the presence of Salmonella in commercial pig farms and to isolate specific autochthonous bacteriophages against Salmonella Typhimurium, to characterize them and to evaluate their lytic capacity against Salmonella Typhimurium in vivo and in vitro. Salmonella was isolated on 50% (4/8) of the farms, with serotype Typhimurium being the most prevalent, detected in 48.2% of samples (13/27). The isolated Salmonella Typhimurium bacteriophages belong to the Podoviridae family, were active against serotypes Abony, Enteritidis, Typhi, and Typhimurium, but not against serotypes Arizonae, Cholerasuis, Gallinarum, and Pullorum. In in vitro tests, bacteriophage at 10(7) PFU/mL and 10(9) PFU/mL significantly reduced (p<0.05) Salmonella Typhimurium counts in 1.6 and 2.5 log10 colony-forming units (CFU)/mL, respectively, after 24 h. Before the in vivo treatment with bacteriophages, Salmonella was identified in 93.3% (28/30) of the fecal samples from the pigs inoculated with 10(6) CFU/mL, and only in 56.6% (17/30) after the treatment consisting of oral administration of the pool of the bacteriophages after the fasting period, simulating a common preslaughter practice. These results indicate that the pool of bacteriophages administered was capable of reducing the colonization of Salmonella in pigs.

Comprehensive analysis of Salmonella sequence polymorphisms and development of a LDR-UA assay for the detection and characterization of selected serotypes.

PubMed

Lauri, Andrea; Castiglioni, Bianca; Mariani, Paola

2011-07-01

Salmonella is a major cause of food-borne disease, and Salmonella enterica subspecies I includes the most clinically relevant serotypes. Salmonella serotype determination is important for the disease etiology assessment and contamination source tracking. This task will be facilitated by the disclosure of Salmonella serotype sequence polymorphisms, here annotated in seven genes (sefA, safA, safC, bigA, invA, fimA, and phsB) from 139 S. enterica strains, of which 109 belonging to 44 serotypes of subsp. I. One hundred nineteen polymorphic sites were scored and associated to single serotypes or to serotype groups belonging to S. enterica subsp. I. A diagnostic tool was constructed based on the Ligation Detection Reaction-Universal Array (LDR-UA) for the detection of polymorphic sites uniquely associated to serotypes of primary interest (Salmonella Hadar, Salmonella Infantis, Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Gallinarum, Salmonella Virchow, and Salmonella Paratyphi B). The implementation of promiscuous probes allowed the diagnosis of ten further serotypes that could be associated to a unique hybridization pattern. Finally, the sensitivity and applicability of the tool was tested on target DNA dilutions and with controlled meat contamination, allowing the detection of one Salmonella CFU in 25 g of meat.

Population Dynamics of Salmonella enterica Serotypes in Commercial Egg and Poultry Production ▿

PubMed Central

Foley, Steven L.; Nayak, Rajesh; Hanning, Irene B.; Johnson, Timothy J.; Han, Jing; Ricke, Steven C.

2011-01-01

Fresh and processed poultry have been frequently implicated in cases of human salmonellosis. Furthermore, increased consumption of meat and poultry has increased the potential for exposure to Salmonella enterica. While advances have been made in reducing the prevalence and frequency of Salmonella contamination in processed poultry, there is mounting pressure on commercial growers to prevent and/or eliminate these human pathogens in preharvest production facilities. Several factors contribute to Salmonella colonization in commercial poultry, including the serovar and the infectious dose. In the early 1900s, Salmonella enterica serovars Pullorum and Gallinarum caused widespread diseases in poultry, but vaccination and other voluntary programs helped eradicate pullorum disease and fowl typhoid from commercial flocks. However, the niche created by the eradication of these serovars was likely filled by S. Enteritidis, which proliferated in the bird populations. While this pathogen remains a significant problem in commercial egg and poultry production, its prevalence among poultry has been declining since the 1990s. Coinciding with the decrease of S. Enteritidis, S. Heidelberg and S. Kentucky have emerged as the predominant serovars in commercial broilers. In this review, we have highlighted bacterial genetic and host-related factors that may contribute to such shifts in Salmonella populations in commercial poultry and intervention strategies that could limit their colonization. PMID:21571882

Immunoblot detection of class-specific humoral immune response to outer membrane proteins isolated from Salmonella typhi in humans with typhoid fever.

PubMed Central

Ortiz, V; Isibasi, A; García-Ortigoza, E; Kumate, J

1989-01-01

The studies reported here were undertaken to assess the ability of the outer membrane proteins (OMPs) of Salmonella typhi to induce a humoral immune response in humans with typhoid fever. OMPs were isolated with the nonionic detergent Triton X-100 and were found to be contaminated with approximately 4% lipopolysaccharide. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns showed protein bands with molecular size ranges from 17 to 70 kilodaltons; the major groups of proteins were those that correspond to the porins and OmpA of gram-negative bacteria. Rabbit antiserum to OMPs or to S. typhi recognized OMPs after absorption with lipopolysaccharide. Sera from patients with typhoid fever contained immunoglobulin M antibodies which reacted with a protein of 28 kilodaltons and immunoglobulin G antibodies which reacted mainly with the porins, as determined by immunoblotting. These results indicate that the porins are the major immunogenic OMPs from S. typhi and that the immune response induced in the infection could be related to the protective status. Images PMID:2768450

Bioprotective potential of bacteriocinogenic Enterococcus gallinarum strains isolated from some Nigerian fermented foods, and of their bacteriocins.

PubMed

Oladipo, Iyabo C; Sanni, Abiodun I; Writachit, Chakraborty; Chakravorty, Somnath; Jana, Sayantan; Rudra, Deep S; Gacchui, Ratan; Swarnakar, Snehasikta

2014-01-01

Enterococcus gallinarum strains isolated from some Nigerian fermented foods were found to produce bacteriocins. The bacteriocins had a broad spectrum of activity against both Gram-positive and negative bacteria. The effects of the bacteriocins and bacteriocinogenic organ- isms on Staphylococcus aureus infections in rats were evaluated. Sprague-Dawley rats were infected with S. aureus MTCC 737 and treated with E. gallinarum T71 and different concentrations of the bacteriocins from E. gallinarum W211 and T71. Staphylococcus aureus infection caused significant upregulation of aspartate aminotransferase and alanine aminotransferase levels in sera of the infected rats. Moreover, gelatin zymography revealed that infected gastric tissues showed elevated matrix metalloproteinase-9 activity. Bacteriocin treatments reduced the MMP-9 activity and inhibited the expressions of both Tumour Necrosis Factor Alpha (TNF-α) and Interleukin-1 Beta (IL-1β) dose dependently, pointing to a potential role of the bacteriocins in attenuating inflammatory responses to Staphylococcus aureus infec- tion. Gastric and GIT damage caused by staphylococcal infection were reduced in the Enterococcus gallinarum T71 and bacteriocin-treated groups also dose dependently. We conclude that these bacteriocins may have useful biomedical applications.

Molecular typing, antibiotic resistance, virulence gene and biofilm formation of different Salmonella enterica serotypes.

PubMed

Turki, Yousra; Mehr, Ines; Ouzari, Hadda; Khessairi, Amel; Hassen, Abdennaceur

2014-01-01

Salmonella enterica isolates representing commonly isolated serotypes in Tunisia were analyzed using genotyping and phenotyping methods. ERIC and ITS-PCR applied to 48 Salmonella spp. isolates revealed the presence of 12 and 10 different profiles, respectively. The distribution of profiles among serotypes demonstrated the presence of strains showing an identical fingerprinting pattern. All Salmonella strains used in this study were positive for the sdiA gene. Three Salmonella isolates belonging to serotypes Anatum, Enteritidis and Amsterdam were negative for the invA gene. The spvC gene was detected in thirteen isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Gallinarum and Montevideo. Antibiotic resistance was frequent among the recovered Salmonella isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Zanzibar and Derby. The majority of these isolates exhibited resistance to at least two antibiotic families. Four multidrug-resistant isolates were recovered from food animals and poultry products. These isolates exhibited not only resistance to tetracycline, sulphonamides, and ampicillin, but also have shown resistance to fluoroquinolones. Common resistance to nalidixic acid, ciprofloxacin and ofloxacin in two S. Anatum and S. Zanzibar strains isolated from raw meat and poultry was also obtained. Furthermore, wastewater and human isolates exhibited frequent resistance to nalidixic acid and tetracycline. Of all isolates, 33.5% were able to form biofilm.

Channel specificity and secondary structure of the glucose-inducible porins of Pseudomonas spp.

PubMed

Adewoye, L O; Tschetter, L; O'Neil, J; Worobec, E A

1998-06-01

The OprB porin-mediated glucose transport system was investigated in Pseudomonas chlororaphis, Burkholderia cepacia, and Pseudomonas fluorescens. Kinetic studies of [U-14C]glucose uptake revealed an inducible system of low Km values (0.3-5 microM) and high specificity for glucose. OprB homologs were purified and reconstituted into proteoliposomes. The porin function and channel preference for glucose were demonstrated by liposome swelling assays. Examination of the periplasmic glucose-binding protein (GBP) components by Western immunoblotting using P. aeruginosa GBP-specific antiserum revealed some homology between P. aeruginosa GBP and periplasmic proteins from P. fluorescens and P. chlororaphis but not B. cepacia. Circular dichroism spectropolarimetry of purified OprB-like porins from the three species revealed beta sheet contents of 31-50% in agreement with 40% beta sheet content for the P. aeruginosa OprB porin. These findings suggest that the high-affinity glucose transport system is primarily specific for glucose and well conserved in the genus Pseudomonas although its outer membrane component may differ in channel architecture and specificity for other carbohydrates.

On the Evolutionary History, Population Genetics and Diversity among Isolates of Salmonella Enteritidis PFGE Pattern JEGX01.0004

PubMed Central

Allard, Marc W.; Luo, Yan; Strain, Errol; Pettengill, James; Timme, Ruth; Wang, Charles; Li, Cong; Keys, Christine E.; Zheng, Jie; Stones, Robert; Wilson, Mark R.; Musser, Steven M.; Brown, Eric W.

2013-01-01

Facile laboratory tools are needed to augment identification in contamination events to trace the contamination back to the source (traceback) of Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis). Understanding the evolution and diversity within and among outbreak strains is the first step towards this goal. To this end, we collected 106 new S. Enteriditis isolates within S. Enteriditis Pulsed-Field Gel Electrophoresis (PFGE) pattern JEGX01.0004 and close relatives, and determined their genome sequences. Sources for these isolates spanned food, clinical and environmental farm sources collected during the 2010 S. Enteritidis shell egg outbreak in the United States along with closely related serovars, S. Dublin, S. Gallinarum biovar Pullorum and S. Gallinarum. Despite the highly homogeneous structure of this population, S. Enteritidis isolates examined in this study revealed thousands of SNP differences and numerous variable genes (n = 366). Twenty-one of these genes from the lineages leading to outbreak-associated samples had nonsynonymous (causing amino acid changes) changes and five genes are putatively involved in known Salmonella virulence pathways. While chromosome synteny and genome organization appeared to be stable among these isolates, genome size differences were observed due to variation in the presence or absence of several phages and plasmids, including phage RE-2010, phage P125109, plasmid pSEEE3072_19 (similar to pSENV), plasmid pOU1114 and two newly observed mobile plasmid elements pSEEE1729_15 and pSEEE0956_35. These differences produced modifications to the assembled bases for these draft genomes in the size range of approximately 4.6 to 4.8 mbp, with S. Dublin being larger (∼4.9 mbp) and S. Gallinarum smaller (4.55 mbp) when compared to S. Enteritidis. Finally, we identified variable S. Enteritidis genes associated with virulence pathways that may be useful markers for the development of rapid surveillance and typing

Trends of the Major Porin Gene (ompF) Evolution: Insight from the Genus Yersinia

PubMed Central

Stenkova, Anna M.; Isaeva, Marina P.; Shubin, Felix N.; Rasskazov, Valeri A.; Rakin, Alexander V.

2011-01-01

OmpF is one of the major general porins of Enterobacteriaceae that belongs to the first line of bacterial defense and interactions with the biotic as well as abiotic environments. Porins are surface exposed and their structures strongly reflect the history of multiple interactions with the environmental challenges. Unfortunately, little is known on diversity of porin genes of Enterobacteriaceae and the genus Yersinia especially. We analyzed the sequences of the ompF gene from 73 Yersinia strains covering 14 known species. The phylogenetic analysis placed most of the Yersinia strains in the same line assigned by 16S rDNA-gyrB tree. Very high congruence in the tree topologies was observed for Y. enterocolitica, Y. kristensenii, Y. ruckeri, indicating that intragenic recombination in these species had no effect on the ompF gene. A significant level of intra- and interspecies recombination was found for Y. aleksiciae, Y. intermedia and Y. mollaretii. Our analysis shows that the ompF gene of Yersinia has evolved with nonrandom mutational rate under purifying selection. However, several surface loops in the OmpF porin contain positively selected sites, which very likely reflect adaptive diversification Yersinia to their ecological niches. To our knowledge, this is a first investigation of diversity of the porin gene covering the whole genus of the family Enterobacteriaceae. This study demonstrates that recombination and positive selection both contribute to evolution of ompF, but the relative contribution of these evolutionary forces are different among Yersinia species. PMID:21655186

Absence of population genetic structure in Heterakis gallinarum of chicken from Sichuan, inferred from mitochondrial cytochrome c oxidase subunit I gene.

PubMed

Gu, Xiaobin; Zhu, Jun-Yang; Jian, Ke-Ling; Wang, Bao-Jian; Peng, Xue-Rong; Yang, Guang-You; Wang, Tao; Zhong, Zhi-Jun; Peng, Ke-Yun

2016-09-01

Population genetics information provides a foundation for understanding the transmission and epidemiology of parasite and, therefore, may be used to assist in the control of parasitosis. However, limited available sequence information in Heterakis gallinarum has greatly impeded the study in this area. In this study, we first investigated the genetic variability and genetic structure of H. gallinarum. The 1325 bp fragments of the mitochondrial COX1 gene were amplified in 56 isolates of H. gallinarum from seven different geographical regions in Sichuan province, China. The 56 sequences were classified into 22 haplotypes (H1-H22). The values of haplotype diversity (0.712) and nucleotide diversity (0.00158) in Sichuan population indicate a rapid expansion occurred from a relatively small, short-term effective population in the past. The haplotype network formed a distribution around H1 in a star-like topology, and the haplotypes did not cluster according to their geographical location. Similar conclusions could be made from MP phylogenetic tree. The Fst value (Fst<0.16965) and AMOVA analysis revealed that no significant genetic differentiation was observed among the seven different geographical populations. Neutrality tests (Tajima's D and Fu's Fs) and mismatch analysis indicated that H. gallinarum experienced a population expansion in the past. Our results indicated that H. gallinarum experienced a rapid population expansion in the past, and there was a low genetic diversity and an absence of population structure across the population.

Whole-Cell-Based Assay To Evaluate Structure Permeation Relationships for Carbapenem Passage through the Pseudomonas aeruginosa Porin OprD.

PubMed

Iyer, Ramkumar; Sylvester, Mark A; Velez-Vega, Camilo; Tommasi, Ruben; Durand-Reville, Thomas F; Miller, Alita A

2017-04-14

The global emergence of antibiotic resistance, especially in Gram-negative bacteria, is an urgent threat to public health. Discovery of novel classes of antibiotics with activity against these pathogens has been impeded by a fundamental lack of understanding of the molecular drivers underlying small molecule uptake. Although it is well-known that outer membrane porins represent the main route of entry for small, hydrophilic molecules across the Gram-negative cell envelope, the structure-permeation relationship for porin passage has yet to be defined. To address this knowledge gap, we developed a sensitive and specific whole-cell approach in Escherichia coli called titrable outer membrane permeability assay system (TOMAS). We used TOMAS to characterize the structure porin-permeation relationships of a set of novel carbapenem analogues through the Pseudomonas aeruginosa porin OprD. Our results show that small structural modifications, especially the number and nature of charges and their position, have dramatic effects on the ability of these molecules to permeate cells through OprD. This is the first demonstration of a defined relationship between specific molecular changes in a substrate and permeation through an isolated porin. Understanding the molecular mechanisms that impact antibiotic transit through porins should provide valuable insights to antibacterial medicinal chemistry and may ultimately allow for the rational design of porin-mediated uptake of small molecules into Gram-negative bacteria.

Enrofloxacin Permeation Pathways across the Porin OmpC.

PubMed

Prajapati, Jigneshkumar Dahyabhai; Solano, Carlos José Fernández; Winterhalter, Mathias; Kleinekathöfer, Ulrich

2018-02-01

In Gram-negative bacteria, the lack or quenching of antibiotic translocation across the outer membrane is one of the main factors for acquiring antibiotic resistance. An atomic-level comprehension of the key features governing the transport of drugs by outer-membrane protein channels would be very helpful in developing the next generation of antibiotics. In a previous study [ J. D. Prajapati et al. J. Chem. Theory Comput. 2017 , 13 , 4553 ], we characterized the diffusion pathway of a ciprofloxacin molecule through the outer membrane porin OmpC of Escherichia coli by combining metadynamics and a zero-temperature string method. Here, we evaluate the diffusion route through the OmpC porin for a similar fluoroquinolone, that is, the enrofloxacin molecule, using the previously developed protocol. As a result, it was found that the lowest-energy pathway was similar to that for ciprofloxacin; namely, a reorientation was required on the extracellular side with the carboxyl group ahead before enrofloxacin reached the constriction region. In turn, the free-energy basins for both antibiotics are located at similar positions in the space defined by selected reaction coordinates, and their affinity sites share a wide number of porin residues. However, there are some important deviations due to the chemical differences of these two drugs. On the one hand, a slower diffusion process is expected for enrofloxacin, as the permeation pathway exhibits higher overall energy barriers, mainly in the constriction region. On the other hand, enrofloxacin needs to replace some polar interactions in its affinity sites with nonpolar ones. This study demonstrates how minor chemical modifications can qualitatively affect the translocation mechanism of an antibiotic molecule.

Assignment of serotype to Salmonella enterica isolates obtained from poultry and their environment in southern Brazil

PubMed Central

Pulido-Landínez, M; Sánchez-Ingunza, R; Guard, J; do Nascimento, V Pinheiro

2013-01-01

To assess diversity of Salmonella enterica serotypes present in poultry and their environment from southern Brazil, the Kauffmann–White–Le Minor (KWL) scheme was used to serotype a total of 155 isolates. Isolates were then re-examined with nested PCR and sequencing of the dkgB-linked intergenic sequence ribotyping (ISR) region that assesses single nucleotide polymorphisms occurring around a 5S ribosomal gene. Serotypes identified were Heidelberg (40·6%), Enteritidis (34·2%), Hadar (8·4%), Typhimurium (3·9%), Gallinarum (3·2%), Agona (1·3%), Cerro (1·3%), Livingstone (1·3%), Infantis (0·6%), Isangi (0·6%), Mbandaka (0·6%), Montevideo (0·6%) and Senftenberg (0·6%). Three unique ISRs were detected from four strains. Day old chicks yielded only S. Enteritidis, whereas S. Heidelberg was most often associated with poultry carcasses. Overall agreement between KWL and ISR was 85·2%, with disagreement possibly due to the ability of ISR to detect mixtures of serotypes in culture. Overall, ISR provided more information than did KWL about the ecology of Salm. enterica on-farm. The O-antigen group D Salm. enterica serovars such as Pullorum, Gallinarum and Enteritidis appear susceptible to overgrowth by other serotypes. Significance and Impact of the Study Single nucleotide polymorphisms found in a group of poultry-associated Salmonella isolates from southern Brazil provided evidence of mixtures of serovar group D serotypes on-farm and in single samples from birds. This finding suggests that co-infection and interserotype competition of Salmonella enterica in poultry could impact the incidence of disease in animals or humans. In addition, unique serotypes were identified on-farm that escaped characterization by antibody typing. Application of cost-efficient and highly discriminatory genomic methods for assigning serotype may alter concepts about the epidemiology of Salm. enterica on-farm and in foods. PMID:23734786

An adaptive response of Enterobacter aerogenes to imipenem: regulation of porin balance in clinical isolates.

PubMed

Lavigne, Jean-Philippe; Sotto, Albert; Nicolas-Chanoine, Marie-Hélène; Bouziges, Nicole; Pagès, Jean-Marie; Davin-Regli, Anne

2013-02-01

Imipenem (IPM) is a carbapenem antibiotic frequently used in severe hospital infections. Several reports have mentioned the emergence of resistant isolates exhibiting membrane modifications. A study was conducted between September 2005 and August 2007 to survey infections due to Enterobacter aerogenes in patients hospitalised in a French university hospital. Resistant E. aerogenes clinical isolates obtained from patients treated with IPM and collected during the 3 months following initiation of treatment were phenotypically and molecularly characterised for β-lactamases, efflux pumps activity and outer membrane proteins. Among the 339 patients infected with E. aerogenes during the study period, 41 isolates (12.1%) were resistant to extended-spectrum cephalosporins and 17 patients (5.0%) were treated with IPM. The isolates from these 17 patients presented TEM-24 and basal efflux expression. Following IPM treatment, an IPM-intermediate-susceptible (IPM-I) isolate emerged in 11 patients and an IPM-resistant (IPM-R) isolate in 6 patients. A change in the porin balance (Omp35/Omp36) was observed in IPM-I isolates exhibiting ertapenem resistance. Finally, a porin deficiency (Omp35 and Omp36 absence) was detected in IPM-R isolates associated with efflux pump expression. This study indicates that the alteration in porin expression, including the shift of porin expression and lack of porins, contribute to the E. aerogenes adaptive response to IPM treatment. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Global survey of Klebsiella pneumoniae major porins from ertapenem non-susceptible isolates lacking carbapenemases.

PubMed

Wise, Mark G; Horvath, Elizabeth; Young, Katherine; Sahm, Daniel F; Kazmierczak, Krystyna M

2018-03-01

To understand the diversity of porin disruption in Klebsiella pneumoniae, the major outer membrane protein (OMP) porins, OmpK35 and OmpK36, were examined in a set of isolates that did not harbour traditional carbapenem-hydrolysing enzymes, but nevertheless tested non-susceptible to ertapenem. A world-wide collection of Klebsiella pneumoniae isolates that were part of the Study for Monitoring Antimicrobial Resistance Trends (SMART) surveillance project over the years 2008-2014 were characterised with regard to their β-lactamase gene carriage and potential permeability defects. Four hundred and eighty-seven isolates that did not carry carbapenemase genes, but were non-susceptible to ertapenem, were investigated by sequence analysis of the genes encoding OmpK35 and OmpK36. Isolates without obvious genetic lesions in either major porin gene were further examined by outer membrane protein SDS-PAGE. The majority of isolates, 83.0 % (404/487), exhibited clear genetic disruption in either or both of the ompK35 and ompK36 genes. Among the proportion of the collection with the highest ertapenem MIC value (>4 mg l -1 ), 60.5 % (115/190) showed mutation in both porin genes. Isolates without obvious genetic mutations were examined by SDS-PAGE, and 90.4 % (75/83) were found to lack or show altered expression of at least one of the major OMPs when compared to an ertapenem sensitive control strain. This study illustrates that porin deficiency in Klebsiella pneumoniae is a widespread phenomenon, and in combination with ESBLs and/or AmpC enzymes, likely accounts for the elevated ertapenem MICs observed in this study.

Improved purification of native meningococcal porin PorB and studies on its structure/function.

PubMed

Massari, Paola; King, Carol A; MacLeod, Heather; Wetzler, Lee M

2005-12-01

The outer membrane protein PorB of Neisseria meningitidis is a pore-forming protein which has various effects on eukaryotic cells. It has been shown to (1) up-regulate the surface expression of the co-stimulatory molecule CD86 and of MHC class II (which are TLR2/MyD88 dependent and related to the porin's immune-potentiating ability), (2) be involved in prevention of apoptosis by modulating the mitochondrial membrane potential, and (3) form pores in eukaryotic cells. As an outer membrane protein, its native trimeric form isolation is complicated by its insoluble nature, requiring the presence of detergent throughout the whole procedure, and by its tight association with other outer membrane components, such as neisserial LOS or lipoproteins. In this study, an improved chromatographic purification method to obtain an homogeneous product free of endotoxin and lipoprotein is described, without loss of any of the above-mentioned properties of the porin. Furthermore, we have investigated the requirement of the native trimeric structure for the porin's activity. Inactivation of functional PorB trimers into non-functional monomers was achieved by incubation on ice. Thus, routine long- and medium-term storage at low temperature may be a cause of porin inactivation.

The OprB porin plays a central role in carbohydrate uptake in Pseudomonas aeruginosa.

PubMed

Wylie, J L; Worobec, E A

1995-06-01

Using interposon mutagenesis, we have generated strains of Pseudomonas aeruginosa which lack or overexpress the substrate-selective OprB porin of this species. A marked decrease or increase in the initial uptake of glucose by these strains verified the role of OprB in facilitating the diffusion of glucose across the outer membrane of P. aeruginosa. However, we also demonstrated that the loss or overexpression of OprB had a similar effect on the uptake of three other sugars able to support the growth of this bacterium (mannitol, glycerol, and fructose). This effect was restricted to carbohydrate transport; arginine uptake was identical in mutant and wild-type strains. These results indicated that OprB cannot be considered strictly a glucose-selective porin; rather, it acts as a central component of carbohydrate transport and is more accurately described as a carbohydrate-selective porin.

Characterization of the porins of Campylobacter jejuni and Campylobacter coli and implications for antibiotic susceptibility.

PubMed Central

Page, W J; Huyer, G; Huyer, M; Worobec, E A

1989-01-01

The major outer membrane protein was extracted from Campylobacter coli by Triton X-100/EDTA fractionation of cell envelopes. This heat-modifiable protein was shown to have pore-forming activity in black lipid bilayers. The C. coli porin formed a relatively small cation-selective pore with a mean single-channel conductance of 0.53 +/- 0.16 nS in 1.0 M KCl. There was no evidence of oligomer formation, which suggested that each protein monomer formed a pore. Pore-forming activity of the C. coli porin and similarly prepared Campylobacter jejuni porin was also measured in liposome-swelling assays. These results confirmed the cation selectivity of both pores. The C. coli porin formed a small pore, which hindered the penetration of solutes with a molecular weight of 262, and a larger pore, which hindered the penetration of solutes with a molecular weight of 340, in a protein-concentration-dependent manner. C. jejuni formed one size of pore that was slightly larger than the C. coli pore and just permitted the passage of solutes, with a molecular weight of 340. A review of the literature concerning in vitro screening of antimicrobial agents tended to confirm the low permeability of the C. jejuni outer membrane to hydrophilic antimicrobial agents except when the molecules had molecular weights of less than 360. The porins of C. jejuni and C. coli may contribute to intrinsic resistance to antimicrobial agents, whereas alternative (nonporin) routes of antimicrobial agent uptake may be more important determinants of susceptibility to antimicrobial agents. Images PMID:2543277

Characterization of the porins of Campylobacter jejuni and Campylobacter coli and implications for antibiotic susceptibility.

PubMed

Page, W J; Huyer, G; Huyer, M; Worobec, E A

1989-03-01

The major outer membrane protein was extracted from Campylobacter coli by Triton X-100/EDTA fractionation of cell envelopes. This heat-modifiable protein was shown to have pore-forming activity in black lipid bilayers. The C. coli porin formed a relatively small cation-selective pore with a mean single-channel conductance of 0.53 +/- 0.16 nS in 1.0 M KCl. There was no evidence of oligomer formation, which suggested that each protein monomer formed a pore. Pore-forming activity of the C. coli porin and similarly prepared Campylobacter jejuni porin was also measured in liposome-swelling assays. These results confirmed the cation selectivity of both pores. The C. coli porin formed a small pore, which hindered the penetration of solutes with a molecular weight of 262, and a larger pore, which hindered the penetration of solutes with a molecular weight of 340, in a protein-concentration-dependent manner. C. jejuni formed one size of pore that was slightly larger than the C. coli pore and just permitted the passage of solutes, with a molecular weight of 340. A review of the literature concerning in vitro screening of antimicrobial agents tended to confirm the low permeability of the C. jejuni outer membrane to hydrophilic antimicrobial agents except when the molecules had molecular weights of less than 360. The porins of C. jejuni and C. coli may contribute to intrinsic resistance to antimicrobial agents, whereas alternative (nonporin) routes of antimicrobial agent uptake may be more important determinants of susceptibility to antimicrobial agents.

Structural and dynamical properties of the porins OmpF and OmpC: insights from molecular simulations

NASA Astrophysics Data System (ADS)

Kumar, Amit; Hajjar, Eric; Ruggerone, Paolo; Ceccarelli, Matteo

2010-11-01

In this paper we investigate the structural and dynamical properties of the two major porins (OmpF and OmpC) in Escherichia coli, using molecular dynamics (MD) simulations. In particular we characterized the atomic fluctuations, correlated motions, temperature dependence, solvent-accessible cross-sectional area and water dynamics in the key regions of the two channels. Our in-depth analysis allows us to highlight the importance of both the key conserved and substituted residues between OmpF and OmpC. The latter is characterized by a narrower and longer constriction region with respect to OmpF. OmpC also showed a higher stability upon increasing temperature. We then present the results of transport properties by using accelerated MD simulations to probe the diffusion of norfloxacin (a fluoroquinolone antibiotic) through the two porins OmpF/OmpC. Our study constitutes a step forward towards understanding the structure-function relationship of the two porins' channels. This will benefit the research of antibacterials with improved permeation properties and nanopores that aim to use these porins as sensing systems.

Evolution of Salmonella enterica Virulence via Point Mutations in the Fimbrial Adhesin

PubMed Central

Kisiela, Dagmara I.; Chattopadhyay, Sujay; Libby, Stephen J.; Karlinsey, Joyce E.; Fang, Ferric C.; Tchesnokova, Veronika; Kramer, Jeremy J.; Beskhlebnaya, Viktoriya; Samadpour, Mansour; Grzymajlo, Krzysztof; Ugorski, Maciej; Lankau, Emily W.; Mackie, Roderick I.; Clegg, Steven; Sokurenko, Evgeni V.

2012-01-01

Whereas the majority of pathogenic Salmonella serovars are capable of infecting many different animal species, typically producing a self-limited gastroenteritis, serovars with narrow host-specificity exhibit increased virulence and their infections frequently result in fatal systemic diseases. In our study, a genetic and functional analysis of the mannose-specific type 1 fimbrial adhesin FimH from a variety of serovars of Salmonella enterica revealed that specific mutant variants of FimH are common in host-adapted (systemically invasive) serovars. We have found that while the low-binding shear-dependent phenotype of the adhesin is preserved in broad host-range (usually systemically non-invasive) Salmonella, the majority of host-adapted serovars express FimH variants with one of two alternative phenotypes: a significantly increased binding to mannose (as in S. Typhi, S. Paratyphi C, S. Dublin and some isolates of S. Choleraesuis), or complete loss of the mannose-binding activity (as in S. Paratyphi B, S. Choleraesuis and S. Gallinarum). The functional diversification of FimH in host-adapted Salmonella results from recently acquired structural mutations. Many of the mutations are of a convergent nature indicative of strong positive selection. The high-binding phenotype of FimH that leads to increased bacterial adhesiveness to and invasiveness of epithelial cells and macrophages usually precedes acquisition of the non-binding phenotype. Collectively these observations suggest that activation or inactivation of mannose-specific adhesive properties in different systemically invasive serovars of Salmonella reflects their dynamic trajectories of adaptation to a life style in specific hosts. In conclusion, our study demonstrates that point mutations are the target of positive selection and, in addition to horizontal gene transfer and genome degradation events, can contribute to the differential pathoadaptive evolution of Salmonella. PMID:22685400

The OprB porin plays a central role in carbohydrate uptake in Pseudomonas aeruginosa.

PubMed Central

Wylie, J L; Worobec, E A

1995-01-01

Using interposon mutagenesis, we have generated strains of Pseudomonas aeruginosa which lack or overexpress the substrate-selective OprB porin of this species. A marked decrease or increase in the initial uptake of glucose by these strains verified the role of OprB in facilitating the diffusion of glucose across the outer membrane of P. aeruginosa. However, we also demonstrated that the loss or overexpression of OprB had a similar effect on the uptake of three other sugars able to support the growth of this bacterium (mannitol, glycerol, and fructose). This effect was restricted to carbohydrate transport; arginine uptake was identical in mutant and wild-type strains. These results indicated that OprB cannot be considered strictly a glucose-selective porin; rather, it acts as a central component of carbohydrate transport and is more accurately described as a carbohydrate-selective porin. PMID:7768797

Differential roles for pathogenicity islands SPI-13 and SPI-8 in the interaction of Salmonella Enteritidis and Salmonella Typhi with murine and human macrophages.

PubMed

Espinoza, Rodrigo A; Silva-Valenzuela, Cecilia A; Amaya, Fernando A; Urrutia, Ítalo M; Contreras, Inés; Santiviago, Carlos A

2017-02-15

Salmonella pathogenicity island (SPI)-13 is conserved in many serovars of S. enterica, including S. Enteritidis, S. Typhimurium and S. Gallinarum. However, it is absent in typhoid serovars such as S. Typhi and Paratyphi A, which carry SPI-8 at the same genomic location. Because the interaction with macrophages is a critical step in Salmonella pathogenicity, in this study we investigated the role played by SPI-13 and SPI-8 in the interaction of S. Enteritidis and S. Typhi with cultured murine (RAW264.7) and human (THP-1) macrophages. Our results showed that SPI-13 was required for internalization of S. Enteritidis in murine but not human macrophages. On the other hand, SPI-8 was not required for the interaction of S. Typhi with human or murine macrophages. Of note, the presence of an intact copy of SPI-13 in a S. Typhi mutant carrying a deletion of SPI-8 did not improve its ability to be internalized by, or survive in human or murine macrophages. Altogether, our results point out to different roles for SPI-13 and SPI-8 during Salmonella infection. While SPI-13 contributes to the interaction of S. Enteritidis with murine macrophages, SPI-8 is not required in the interaction of S. Typhi with murine or human macrophages. We hypothesized that typhoid serovars have lost SPI-13 and maintained SPI-8 to improve their fitness during another phase of human infection.

Molecular characterization of the Serratia marcescens OmpF porin, and analysis of S. marcescens OmpF and OmpC osmoregulation.

PubMed

Hutsul, J A; Worobec, E

1997-08-01

Serratia marcescens is a nosocomial pathogen with a high incidence of beta-lactam resistance. Reduced amounts of outer-membrane porins have been correlated with increased resistance to beta-lactams but only one porin, OmpC, has been characterized at the molecular level. In this study we present the molecular characterization of a second porin, OmpF, and an analysis of the expression of S. marcescens porins in response to various environmental changes. Two porins were isolated from the outer membrane using urea-SDS-PAGE and the relative amounts were shown to be influenced by the osmolarity of the medium and the presence of salicylate. From a S. marcescens genomic DNA library an 8 kb EcoRI fragment was isolated that hybridized with an oligonucleotide encoding the published N-terminal amino acid sequence of the S. marcescens 41 kDa porin. A 41 kDa protein was detected in the outer membrane of Escherichia coli NM522 carrying the cloned S. marcescens DNA. The cloned gene was sequenced and shown to code for a protein that shared 60-70% identity with other known OmpF and OmpC sequences. The upstream DNA sequence of the S. marcescens gene was similar to the corresponding E. coli ompF sequence; however, a regulatory element important in repression of E. coli ompF at high osmolarity was absent. The cloned S. marcescens OmpF in E. coli increased in expression in conditions of high osmolarity. The potential involvement of micF in the observed osmoregulation of S. marcescens porins is discussed.

Densely packed beta-structure at the protein-lipid interface of porin is revealed by high-resolution cryo-electron microscopy.

PubMed

Sass, H J; Büldt, G; Beckmann, E; Zemlin, F; van Heel, M; Zeitler, E; Rosenbusch, J P; Dorset, D L; Massalski, A

1989-09-05

Porin is an integral membrane protein that forms channels across the outer membrane of Escherichia coli. Electron microscopic studies of negatively stained two-dimensional porin crystals have shown three stain accumulations per porin trimer, revealing the locations of pores spanning the membrane. In this study, reconstituted porin lattices embedded in glucose were investigated using the low-dose technique on a cryo-electron microscope equipped with a helium-cooled superconducting objective lens. The specimen temperature was maintained at 5 K to yield an improved microscopic and specimen stability. Under these conditions, we obtained for the first time electron diffraction patterns from porin lattices to a resolution of 3.2 A and images showing optical diffraction up to a resolution of 4.9 A. Applying correlation averaging techniques to the digitized micrographs, we were able to reconstruct projected images of the porin trimer to a resolution of up to 3.5 A. In the final projection maps, amplitudes from electron diffraction and phases from these images were combined. The predominant feature is a high-density narrow band (about 6 A in thickness) that delineates the outer perimeter of the trimer. Since the molecule consists of almost exclusively beta-sheet structure, as revealed by spectroscopic data, we conclude that this band is a cylindrical beta-pleated sheet crossing the membrane nearly perpendicularly to its plane. Another intriguing finding is a low-density area (about 70 A2) situated in the centre of the trimer.

Patterns of genome evolution that have accompanied host adaptation in Salmonella

PubMed Central

Langridge, Gemma C.; Fookes, Maria; Connor, Thomas R.; Feltwell, Theresa; Feasey, Nicholas; Parsons, Bryony N.; Seth-Smith, Helena M. B.; Barquist, Lars; Stedman, Anna; Humphrey, Tom; Wigley, Paul; Peters, Sarah E.; Maskell, Duncan J.; Corander, Jukka; Chabalgoity, Jose A.; Barrow, Paul; Parkhill, Julian; Dougan, Gordon; Thomson, Nicholas R.

2015-01-01

Many bacterial pathogens are specialized, infecting one or few hosts, and this is often associated with more acute disease presentation. Specific genomes show markers of this specialization, which often reflect a balance between gene acquisition and functional gene loss. Within Salmonella enterica subspecies enterica, a single lineage exists that includes human and animal pathogens adapted to cause infection in different hosts, including S. enterica serovar Enteritidis (multiple hosts), S. Gallinarum (birds), and S. Dublin (cattle). This provides an excellent evolutionary context in which differences between these pathogen genomes can be related to host range. Genome sequences were obtained from ∼60 isolates selected to represent the known diversity of this lineage. Examination and comparison of the clades within the phylogeny of this lineage revealed signs of host restriction as well as evolutionary events that mark a path to host generalism. We have identified the nature and order of events for both evolutionary trajectories. The impact of functional gene loss was predicted based upon position within metabolic pathways and confirmed with phenotyping assays. The structure of S. Enteritidis is more complex than previously known, as a second clade of S. Enteritidis was revealed that is distinct from those commonly seen to cause disease in humans or animals, and that is more closely related to S. Gallinarum. Isolates from this second clade were tested in a chick model of infection and exhibited a reduced colonization phenotype, which we postulate represents an intermediate stage in pathogen–host adaptation. PMID:25535353

Engineering sucrose metabolism in Pseudomonas putida highlights the importance of porins.

PubMed

Löwe, Hannes; Sinner, Peter; Kremling, Andreas; Pflüger-Grau, Katharina

2018-05-28

Using agricultural wastes as a substrate for biotechnological processes is of great interest in industrial biotechnology. A prerequisite for using these wastes is the ability of the industrially relevant microorganisms to metabolize the sugars present therein. Therefore, many metabolic engineering approaches are directed towards widening the substrate spectrum of the workhorses of industrial biotechnology like Escherichia coli, yeast or Pseudomonas putida. For instance, neither xylose or arabinose from cellulosic residues, nor sucrose, the main sugar in waste molasses, can be metabolized by most E. coli and P. putida wild types. We evaluated a new, so far uncharacterized gene cluster for sucrose metabolism from Pseudomonas protegens Pf-5 and showed that it enables P. putida to grow on sucrose as the sole carbon and energy source. Even when integrated into the genome of P. putida, the resulting strain grew on sucrose at rates similar to the rate of the wild type on glucose - making it the fastest growing, plasmid-free P. putida strain known so far using sucrose as substrate. Next, we elucidated the role of the porin, an orthologue of the sucrose porin ScrY, in the gene cluster and found that in P. putida, a porin is needed for sucrose transport across the outer membrane. Consequently, native porins were not sufficient to allow unlimited growth on sucrose. Therefore, we concluded that the outer membrane can be a considerable barrier for substrate transport, depending on strain, genotype and culture conditions, all of which should be taken into account in metabolic engineering approaches. We additionally showed the potential of the engineered P. putida strains by growing them on molasses with efficiencies twice as high as obtained with the wild-type P. putida. This can be seen as a further step towards the production of low-value chemicals and biofuels with P. putida from alternative and more affordable substrates in the future. © 2018 The Authors

Electron crystallography of PhoE porin, an outer membrane, channel- forming protein from E. coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walian, P.J.

1989-11-01

One approach to studying the structure of membrane proteins is the use of electron crystallography. Dr. Bing Jap has crystallized PhoE pore-forming protein (porin) from the outer membrane of escherichia coli (E. coli) into monolayer crystals. The findings of this research and those of Jap (1988, 1989) have determined these crystals to be highly ordered, yielding structural information to a resolution of better than 2.8 angstroms. The task of this thesis has been to collect and process the electron diffraction patterns necessary to generate a complete three-dimensional set of high resolution structure factor amplitudes of PhoE porin. Fourier processing ofmore » these amplitudes when combined with the corresponding phase data is expected to yield the three-dimensional structure of PhoE porin at better than 3.5 angstroms resolution. 92 refs., 33 figs., 3 tabs. (CBS)« less

Validation of Thermal Lethality against Salmonella enterica in Poultry Offal during Rendering.

PubMed

Jones-Ibarra, Amie-Marie; Acuff, Gary R; Alvarado, Christine Z; Taylor, T Matthew

2017-09-01

Recent outbreaks of human disease following contact with companion animal foods cross-contaminated with enteric pathogens, such as Salmonella enterica, have resulted in increased concern regarding the microbiological safety of animal foods. Additionally, the U.S. Food and Drug Administration Food Safety Modernization Act and its implementing rules have stipulated the implementation of current good manufacturing practices and food safety preventive controls for livestock and companion animal foods. Animal foods and feeds are sometimes formulated to include thermally rendered animal by-product meals. The objective of this research was to determine the thermal inactivation of S. enterica in poultry offal during rendering at differing temperatures. Raw poultry offal was obtained from a commercial renderer and inoculated with a mixture of Salmonella serovars Senftenberg, Enteritidis, and Gallinarum (an avian pathogen) prior to being subjected to heating at 150, 155, or 160°F (65.5, 68.3, or 71.1°C) for up to 15 min. Following heat application, surviving Salmonella bacteria were enumerated. Mean D-values for the Salmonella cocktail at 150, 155, and 160°F were 0.254 ± 0.045, 0.172 ± 0.012, and 0.086 ± 0.004 min, respectively, indicative of increasing susceptibility to increased application of heat during processing. The mean thermal process constant (z-value) was 21.948 ± 3.87°F. Results indicate that a 7.0-log-cycle inactivation of Salmonella may be obtained from the cumulative lethality encountered during the heating come-up period and subsequent rendering of raw poultry offal at temperatures not less than 150°F. Current poultry rendering procedures are anticipated to be effective for achieving necessary pathogen control when completed under sanitary conditions.

Multiple environmental factors regulate the expression of the carbohydrate-selective OprB porin of Pseudomonas aeruginosa.

PubMed

Adewoye, L O; Worobec, E A

1999-12-01

In response to low extracellular glucose concentration, Pseudomonas aeruginosa induces the expression of the outer membrane carbohydrate-selective OprB porin. The promoter region of the oprB gene was cloned into a lacZ transcriptional fusion vector, and the construct was mobilized into P. aeruginosa OprB-deficient strain, WW100, to evaluate additional environmental factors that influence OprB porin gene expression. Growth temperature, pH of the growth medium, salicylate concentration, and carbohydrate source were found to differentially influence porin expression. This expression pattern was compared to those of whole-cell [14C]glucose uptake under conditions of high osmolarity, ionicity, variable pH, growth temperatures, and carbohydrate source. These studies revealed that the high-affinity glucose transport genes are down-regulated by salicylic acid, differentially regulated by pH and temperature, and are specifically responsive to exogenous glucose induction.

Transcriptional Analysis of the vanC Cluster from Enterococcus gallinarum Strains with Constitutive and Inducible Vancomycin Resistance

PubMed Central

Panesso, Diana; Abadía-Patiño, Lorena; Vanegas, Natasha; Reynolds, Peter E.; Courvalin, Patrice; Arias, Cesar A.

2005-01-01

The vanC glycopeptide resistance gene cluster encodes enzymes required for synthesis of peptidoglycan precursors ending in d-Ala-d-Ser. Enterococcus gallinarum BM4174 and SC1 are constitutively and inducibly resistant to vancomycin, respectively. Analysis of peptidoglycan precursors in both strains indicated that UDP-MurNAc-tetrapeptide and UDP-MurNAc-pentapeptide[d-Ser] were synthesized in E. gallinarum SC1 only in the presence of vancomycin (4 μg/ml), whereas the “resistance” precursors accumulated in the cytoplasm of BM4174 cells under both inducing and noninducing conditions. Northern hybridization and reverse transcription-PCR experiments revealed that all the genes from the cluster, vanC-1, vanXYC, vanT, vanRC, and vanSC, were transcribed from a single promoter. In the inducible SC1 isolate, transcriptional regulation appeared to be responsible for inducible expression of resistance. Promoter mapping in E. gallinarum BM4174 revealed that the transcriptional start site was located 30 nucleotides upstream from vanC-1 and that the −10 promoter consensus sequence had high identity with that of the vanA cluster. Comparison of the deduced sequence of the vanSC genes from isolates with constitutive and inducible resistance revealed several amino acid substitutions located in the X box (R200L) and in the region between the F and G2 boxes (D312N, D312A, and G320S) of the putative sensor kinase proteins from isolates with constitutive resistance. PMID:15728903

Enhancement of extracellular electron transfer and bioelectricity output by synthetic porin.

PubMed

Yong, Yang-Chun; Yu, Yang-Yang; Yang, Yun; Liu, Jing; Wang, Jing-Yuan; Song, Hao

2013-02-01

The microbial fuel cell (MFC), is a promising environmental biotechnology for harvesting electricity energy from organic wastes. However, low bacterial membrane permeability of electron shuttles is a limiting factor that restricts the electron shuttle-mediated extracellular electron transfer (EET) from bacteria to electrodes, thus the electricity power output of MFCs. To this end, we heterologously expressed a porin protein OprF from Pseudomonas aeruginosa PAO1 into Escherichia coli, which dramatically increased its membrane permeability, delivering a much higher current output in MFCs than its parental strain (BL21). We found that the oprF-expression strain showed more efficient EET than its parental strain. More strikingly, the enhanced membrane permeability also rendered the oprF-expression strain an efficient usage of riboflavin as the electron shuttle, whereas its parental strain was incapable of. Our results substantiated that membrane permeability is crucial for the efficient EET, and indicated that the expression of synthetic porins could be an efficient strategy to enhance bioelectricity generation by microorganisms (including electrogenic bacteria) in MFCs. Copyright © 2012 Wiley Periodicals, Inc.

Direct observation of gold nanoparticle assemblies with the porin MspA on mica.

PubMed

Basel, Matthew T; Dani, Raj Kumar; Kang, Myungshim; Pavlenok, Mikhail; Chikan, Viktor; Smith, Paul E; Niederweis, Michael; Bossmann, Stefan H

2009-02-24

The octameric porin MspA from Mycobacterium smegmatis is sufficiently stable to form a nonmembrane-supported stand-alone porin on mica surfaces. About 98% of all MspA octamers were found to stand upright on mica, with their periplasmic loop regions bound to the hydrophilic mica surface. Both, small (d = 3.7 nm) and large (d = 17 nm) gold nanoparticles bind to MspA, however, in different positions: small gold nanoparticles bind within the MspA pore, whereas the large gold nanoparticles bind to the upper region of MspA. These experiments demonstrate that gold nanoparticles can be positioned at different, well-defined distances from the underlying surface using the MspA pore as a template. These findings represent a significant step toward the use of electrically insulating stable proteins in combination with metal nanoparticles in nanodevices.

Direct Observation of Gold Nanoparticle Assemblies with the Porin MspA on Mica

PubMed Central

Basel, Matthew T.; Dani, Raj Kumar; Kang, Myungshim; Pavlenok, Mikhail; Chikan, Viktor; Smith, Paul E.; Niederweis, Michael

2009-01-01

The octameric porin MspA from Mycobacterium smegmatis is sufficiently stable to form a non-membrane-supported stand-alone porin on Mica surfaces. About 98% of all MspA octamers were found to stand upright on Mica, with their periplasmic loop regions bound to the hydrophilic Mica surface. Both, small (d = 3.7 nm) and large (d = 17 nm) gold nanoparticles bind to MspA, however in different positions: small gold nanoparticles bind within the MspA pore, whereas the large gold nanoparticles bind to the upper region of MspA. These experiments demonstrate that gold nanoparticles can be positioned at different, well-defined distances from the underlying surface using the MspA pore as a template. These findings represent a significant step towards the use of electrically insulating stable proteins in combination with metal nanoparticles in nanodevices. PMID:19236086

SEROVARS AND ANTIMICROBIAL RESISTANCE OF Salmonella spp. ISOLATED FROM TURKEY AND BROILER CARCASSES IN SOUTHERN BRAZIL BETWEEN 2004 AND 2006

PubMed Central

PALMEIRA, Andre; dos SANTOS, Luciana Ruschel; BORSOI, Anderlise; RODRIGUES, Laura Beatriz; CALASANS, Max; do NASCIMENTO, Vladimir Pinheiro

2016-01-01

Salmonella spp. causes diseases in fowls, when species-specific serovars (Salmonella Pullorum and S.Gallinarum) are present in flocks, and public health problems, when non-typhoid serovars are isolated, as well as possible bacterial resistance induced by the preventive and therapeutic use of antimicrobials in animal production. This study describes the serovars and bacterial resistance of 280Salmonella spp. strains isolated from turkey and broiler carcasses in Southern Brazil between 2004 and 2006. SalmonellaEnteritidis was the most prevalent serovar (55.7%), followed by Heidelberg (5.0%), Agona (4.3%), Bredeney (3.9%), Hadar (3.2%), and Typhimurium (2.9%). Tennessee and S. Enterica subspecies enterica(O: 4.5) were isolated only in turkeys, and Hadar (18.6%) was the most prevalent serovar in this species. Antimicrobial susceptibility tests were performed in 178 isolates (43 from turkeys and 135 from broilers). All isolates were sensitive to amoxicillin + clavulanic acid, polymyxin B, ciprofloxacin, and norfloxacin, and were resistant to bacitracin and penicillin. Broiler carcass isolates showed resistance to nalidixic acid (48.9%), nitrofurantoin (34.3%), neomycin (9.6%), tetracycline (5.2%), and kanamycin (8.9%); and turkey carcass isolates were resistant to nalidixic acid (62.8%), tetracycline (34.9%), and neomycin (30.2%), with a significant difference in turkeys when compared to broiler carcass isolates. These results indicate the need for judicious use of antimicrobials in livestock production, given that the serovars identified are potential causes of food poisoning. PMID:27007562

Porins in the Cell Wall of Mycobacteria

NASA Astrophysics Data System (ADS)

Trias, Joaquim; Jarlier, Vincent; Benz, Roland

1992-11-01

The cell wall of mycobacteria is an efficient permeability barrier that makes mycobacteria naturally resistant to most antibiotics. Liposome swelling assays and planar bilayer experiments were used to investigate the diffusion process of hydrophilic molecules through the cell wall of Mycobacterium chelonae and identify the main hydrophilic pathway. A 59-kilodalton cell wall protein formed a water-filled channel with a diameter of 2.2 nanometers and an average single-channel conductance equal to 2.7 nanosiemens in 1 M potassium chloride. These results suggest that porins can be found in the cell wall of a Gram-positive bacterium. A better knowledge of the hydrophilic pathways should help in the design of more effective antimycobacterial agents.

In vivo anthelmintic efficacy of Aloe ferox, Agave sisalana, and Gunnera perpensa in village chickens naturally infected with Heterakis gallinarum.

PubMed

Mwale, Marizvikuru; Masika, Patrick Julius

2015-01-01

The study was conducted to determine the anthelmintic efficacy of Aloe ferox, Agave sisalana, and Gunnera perpensa against Heterakis gallinarum in village chickens. The chickens naturally infected with H. gallinarum were randomly divided into 14 groups of eight chickens and orally administered distilled water (negative control), mebendazole (positive control), and graded levels (50-, 100-, 200-, and 400-mg/kg doses) of the three plant extracts. At days 0, 7, and 14, the floatation technique was used to determine fecal egg counts and H. gallinarum worms from chicken ceca were counted at days 0 and 14. Egg count reduction percentage (ECR%) was high at day 7 for all the test materials except for A. sisalana (100 mg/kg) that had 33%. At day 14, ECR% was high for all the other test materials save for A. ferox (200 mg/kg), mebendazole, and distilled water which was 50, 32, and 50%, respectively. A. ferox (200 mg/kg), G. perpensa (200 and 400 mg/kg), and A. sisalana (50 and 100 mg/kg) had the highest (85, 78, 74, 86, and 73%, respectively) worm count reduction percentage. The plants had anthelmintic properties. Advocacy and utilization of these plants in improving the health of village chickens could lead to increased productivity, boosting profits for the poultry industry thereby enabling it to meet the supply of animal protein and enhance livelihoods. It is imperative to determine compounds in the crude extracts of these medicinal plants which are responsible for the anthelmintic activities and their mechanism of action.

Structure of the membrane channel porin from Rhodopseudomonas blastica at 2.0 A resolution.

PubMed Central

Kreusch, A.; Neubüser, A.; Schiltz, E.; Weckesser, J.; Schulz, G. E.

1994-01-01

The crystal structure of a membrane channel, homotrimeric porin from Rhodopseudomonas blastica has been determined at 2.0 A resolution by multiple isomorphous replacement and structural refinement. The current model has an R-factor of 16.5% and consists of 289 amino acids, 238 water molecules, and 3 detergent molecules per subunit. The partial protein sequence and subsequently the complete DNA sequence were determined. The general architecture is similar to those of the structurally known porins. As a particular feature there are 3 adjacent binding sites for n-alkyl chains at the molecular 3-fold axis. The side chain arrangement in the channel indicates a transverse electric field across each of the 3 pore eyelets, which may explain the discrimination against nonpolar solutes. Moreover, there are 2 significantly ordered girdles of aromatic residues at the nonpolar/polar borderlines of the interface between protein and membrane. Possibly, these residues shield the polypeptide conformation against adverse membrane fluctuations. PMID:8142898

Genomic analyses of bacterial porin-cytochrome gene clusters

DOE PAGES

Shi, Liang; Fredrickson, James K.; Zachara, John M.

2014-11-26

In this study, the porin-cytochrome (Pcc) protein complex is responsible for trans-outer membrane electron transfer during extracellular reduction of Fe(III) by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens PCA. The identified and characterized Pcc complex of G. sulfurreducens PCA consists of a porin-like outer-membrane protein, a periplasmic 8-heme c type cytochrome (c-Cyt) and an outer-membrane 12-heme c-Cyt, and the genes encoding the Pcc proteins are clustered in the same regions of genome (i.e., the pcc gene clusters) of G. sulfurreducens PCA. A survey of additionally microbial genomes has identified the pcc gene clusters in all sequenced Geobacter spp. and other bacteriamore » from six different phyla, including Anaeromyxobacter dehalogenans 2CP-1, A. dehalogenans 2CP-C, Anaeromyxobacter sp. K, Candidatus Kuenenia stuttgartiensis, Denitrovibrio acetiphilus DSM 12809, Desulfurispirillum indicum S5, Desulfurivibrio alkaliphilus AHT2, Desulfurobacterium thermolithotrophum DSM 11699, Desulfuromonas acetoxidans DSM 684, Ignavibacterium album JCM 16511, and Thermovibrio ammonificans HB-1. The numbers of genes in the pcc gene clusters vary, ranging from two to nine. Similar to the metal-reducing (Mtr) gene clusters of other Fe(III)-reducing bacteria, such as Shewanella spp., additional genes that encode putative c-Cyts with predicted cellular localizations at the cytoplasmic membrane, periplasm and outer membrane often associate with the pcc gene clusters. This suggests that the Pcc-associated c-Cyts may be part of the pathways for extracellular electron transfer reactions. The presence of pcc gene clusters in the microorganisms that do not reduce solid-phase Fe(III) and Mn(IV) oxides, such as D. alkaliphilus AHT2 and I. album JCM 16511, also suggests that some of the pcc gene clusters may be involved in extracellular electron transfer reactions with the substrates other than Fe(III) and Mn(IV) oxides.« less

Modification of Salmonella Lipopolysaccharides Prevents the Outer Membrane Penetration of Novobiocin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobre, Thatyane M.; Martynowycz, Michael W.; Andreev, Konstantin

Small hydrophilic antibiotics traverse the outer membrane of Gram-negative bacteria through porin channels. Large lipophilic agents traverse the outer membrane through its bilayer, containing a majority of lipopolysaccharides in its outer leaflet. Genes controlled by the two-component regulatory system PhoPQ modify lipopolysaccharides. We isolate lipopolysaccharides from isogenic mutants of Salmonella sp., one lacking the modification, the other fully modified. These lipopolysaccharides were reconstituted asmonolayers at the air-water interface, and their properties, aswell as their interaction with a large lipophilic drug, novobiocin, was studied. X-ray reflectivity showed that the drug penetrated the monolayer of the unmodified lipopolysaccharides reaching the hydrophobic region,butwasmore » prevented fromthis penetration intothemodified lipopolysaccharides.Results correlatewith behavior of bacterial cells, which become resistant to antibiotics after PhoPQ-regulated modifications. Grazing incidence x-ray diffraction showed that novobiocin produced a striking increase in crystalline coherence length, and the size of the near-crystalline domains.« less

Helicobacter pylori HopE and HopV porins present scarce expression among clinical isolates

PubMed Central

Lienlaf, Maritza; Morales, Juan Pablo; Díaz, María Inés; Díaz, Rodrigo; Bruce, Elsa; Siegel, Freddy; León, Gloria; Harris, Paul R; Venegas, Alejandro

2010-01-01

AIM: To evaluate how widely Helicobacter pylori (H. pylori) HopE and HopV porins are expressed among Chilean isolates and how seroprevalent they are among infected patients in Chile. METHODS: H. pylori hopE and hopV genes derived from strain CHCTX-1 were cloned by polymerase chain reaction (PCR), sequenced and expressed in Escherichia coli AD494 (DE3). Gel-purified porins were used to prepare polyclonal antibodies. The presence of both genes was tested by PCR in a collection of H. pylori clinical isolates and their expression was detected in lysates by immunoblotting. Immune responses against HopE, HopV and other H. pylori antigens in sera from infected and non-infected patients were tested by Western blotting using these sera as first antibody on recombinant H. pylori antigens. RESULTS: PCR and Western blotting assays revealed that 60 and 82 out of 130 Chilean isolates carried hopE and hopV genes, respectively, but only 16 and 9, respectively, expressed these porins. IgG serum immunoreactivity evaluation of 69 H. pylori-infected patients revealed that HopE and HopV were infrequently recognized (8.7% and 10.1% respectively) compared to H. pylori VacA (68.1%) and CagA (59.5%) antigens. Similar values were detected for IgA serum immunoreactivity against HopE (11.6%) and HopV (10.5%) although lower values for VacA (42%) and CagA (17.4%) were obtained when compared to the IgG response. CONCLUSION: A scarce expression of HopE and HopV among Chilean isolates was found, in agreement with the infrequent seroconversion against these antigens when tested in infected Chilean patients. PMID:20082477

Assessing the efficacy of vesicle fusion with planar membrane arrays using a mitochondrial porin as reporter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pszon-Bartosz, Kamila; Hansen, Jesper S.; Technical University of Denmark, Department of Micro- and Nanotechnology, DK-2800 Kongens Lyngby

2011-03-04

Research highlights: {yields} We have established a vesicle fusion efficacy assay based on the major non-specific porin of Fusobacterium nucleatum (FomA). {yields} Maximal fusion obtained was almost 150,000 porin insertions during 20 min. {yields} Incorporation can be either first order or exponential kinetics which has implications for establishing protein delivery to biomimetic membranes. -- Abstract: Reconstitution of functionally active membrane protein into artificially made lipid bilayers is a challenge that must be overcome to create a membrane-based biomimetic sensor and separation device. In this study we address the efficacy of proteoliposome fusion with planar membrane arrays. We establish a proteinmore » incorporation efficacy assay using the major non-specific porin of Fusobacterium nucleatum (FomA) as reporter. We use electrical conductance measurements and fluorescence microscopy to characterize proteoliposome fusion with an array of planar membranes. We show that protein reconstitution in biomimetic membrane arrays may be quantified using the developed FomA assay. Specifically, we show that FomA vesicles are inherently fusigenic. Optimal FomA incorporation is obtained with a proteoliposome lipid-to-protein molar ratio (LPR) = 50 more than 10{sup 5} FomA proteins could be incorporated in a bilayer array with a total membrane area of 2 mm{sup 2} within 20 min. This novel assay for quantifying protein delivery into lipid bilayers may be a useful tool in developing biomimetic membrane applications.« less

Virulence Characterisation of Salmonella enterica Isolates of Differing Antimicrobial Resistance Recovered from UK Livestock and Imported Meat Samples

PubMed Central

Card, Roderick; Vaughan, Kelly; Bagnall, Mary; Spiropoulos, John; Cooley, William; Strickland, Tony; Davies, Rob; Anjum, Muna F.

2016-01-01

Salmonella enterica is a foodborne zoonotic pathogen of significant public health concern. We have characterized the virulence and antimicrobial resistance gene content of 95 Salmonella isolates from 11 serovars by DNA microarray recovered from UK livestock or imported meat. Genes encoding resistance to sulphonamides (sul1, sul2), tetracycline [tet(A), tet(B)], streptomycin (strA, strB), aminoglycoside (aadA1, aadA2), beta-lactam (blaTEM), and trimethoprim (dfrA17) were common. Virulence gene content differed between serovars; S. Typhimurium formed two subclades based on virulence plasmid presence. Thirteen isolates were selected by their virulence profile for pathotyping using the Galleria mellonella pathogenesis model. Infection with a chicken invasive S. Enteritidis or S. Gallinarum isolate, a multidrug resistant S. Kentucky, or a S. Typhimurium DT104 isolate resulted in high mortality of the larvae; notably presence of the virulence plasmid in S. Typhimurium was not associated with increased larvae mortality. Histopathological examination showed that infection caused severe damage to the Galleria gut structure. Enumeration of intracellular bacteria in the larvae 24 h post-infection showed increases of up to 7 log above the initial inoculum and transmission electron microscopy (TEM) showed bacterial replication in the haemolymph. TEM also revealed the presence of vacuoles containing bacteria in the haemocytes, similar to Salmonella containing vacuoles observed in mammalian macrophages; although there was no evidence from our work of bacterial replication within vacuoles. This work shows that microarrays can be used for rapid virulence genotyping of S. enterica and that the Galleria animal model replicates some aspects of Salmonella infection in mammals. These procedures can be used to help inform on the pathogenicity of isolates that may be antibiotic resistant and have scope to aid the assessment of their potential public and animal health risk. PMID:27199965

Site-directed mutagenesis studies to probe the role of specific residues in the external loop (L3) of OmpF and OmpC porins in susceptibility of Serratia marcescens to antibiotics.

PubMed

Begic, Sanela; Worobec, Elizabeth A

2007-06-01

Serratia marcescens is a nosocomial bacterium with natural resistance to a broad spectrum of antibiotics, making treatment challenging. One factor contributing to this natural antibiotic resistance is reduced outer membrane permeability, controlled in part by OmpF and OmpC porin proteins. To investigate the direct role of these porins in the diffusion of antibiotics across the outer membrane, we have created an ompF-ompC porin-deficient strain of S. marcescens. A considerable similarity between the S. marcescens porins and those from other members of Enterobacteriaceae was detected by sequence alignment, with the exception of a change in a conserved region of the third external loop (L3) of the S. marcescens OmpC protein. Serratia marcescens OmpC has aspartic acid instead of glycine in position 112, methionine instead of aspartic acid in position 114, and glutamine in position 124, while in S. marcescens OmpF this is a glycine at position 124. To investigate the role of amino acid positions 112, 114, and 124 and how the observed changes within OmpC porin may play a part in pore permeability, 2 OmpC sites were altered in the Enterobacteriaceae consensus (D112G and M114D) through site-directed mutagenesis. Also, Q124G in OmpC, G124Q in OmpF, and double mutants of these amino acid residues were constructed. Antibiotic accumulation assays and minimal inhibitory concentrations of the strains harboring the mutated porins were performed, while liposome swelling experiments were performed on purified porins. Our results demonstrate that the amino acid at position 114 is not responsible for either antibiotic size or ionic selection, the amino acid at position 112 is responsible for size selection only, and position 124 is involved in both size and ionic selection.

Porins of Pseudomonas fluorescens MFO as fibronectin-binding proteins.

PubMed

Rebière-Huët, J; Guérillon, J; Pimenta, A L; Di Martino, P; Orange, N; Hulen, C

2002-09-24

Bacterial adherence is a complex phenomenon involving specific interactions between receptors, including matricial fibronectin, and bacterial ligands. We show here that fibronectin and outer membrane proteins of Pseudomonas fluorescens were able to inhibit adherence of P. fluorescens to fibronectin-coated wells. We identified at least six fibronectin-binding proteins with molecular masses of 70, 55, 44, 37, 32 and 28 kDa. The presence of native (32 kDa) and heat-modified forms (37 kDa) of OprF was revealed by immuno-analysis and the 44-kDa band was composed of three proteins, their N-terminal sequences showing homologies with Pseudomonas aeruginosa porins (OprD, OprE1 and OprE3).

Characterization of Ciprofloxacin Permeation Pathways across the Porin OmpC Using Metadynamics and a String Method.

PubMed

Prajapati, Jigneshkumar Dahyabhai; Fernández Solano, Carlos José; Winterhalter, Mathias; Kleinekathöfer, Ulrich

2017-09-12

The rapid spreading of antimicrobial resistance in Gram-negative bacteria has become a major threat for humans as well as animals. As one of the main factors involved, the permeability of the outer membrane has attracted a great deal of attention recently. However, the knowledge regarding the translocation mechanisms for most available antibiotics is so far rather limited. Here, a theoretical study concerning the diffusion route of ciprofloxacin across the outer membrane porin OmpC from E. coli is presented. To this end, we establish a protocol to characterize meaningful permeation pathways by combining metadynamics with the zero-temperature string method. It was found that the lowest-energy pathway requires a reorientation of ciprofloxacin in the extracellular side of the porin before reaching the constriction region with its carboxyl group ahead. Several affinity sites have been identified, and their metastability has been evaluated using unbiased simulations. Such a detailed understanding is potentially very helpful in guiding the development of next generation antibiotics.

On the targeting and membrane assembly of the Escherichia coli outer membrane porin, PhoE.

PubMed

Phoenix, D A

1996-12-01

Within gram-negative bacteria such as Escherichia coli, the outer membrane porins provide a relatively non-specific uptake route which is utilised by a wide range of solutes including many antibiotics. Understanding the targeting and membrane assembly of these proteins is therefore of importance and this mini review aims to discuss this process in light of present knowledge.

The Role of OmpK35, OmpK36 Porins, and Production of β-Lactamases on Imipenem Susceptibility in Klebsiella pneumoniae Clinical Isolates, Cairo, Egypt.

PubMed

Wassef, Mona; Abdelhaleim, Mona; AbdulRahman, Eiman; Ghaith, Doaa

2015-12-01

OmpK35 and OmpK36 are the major outer membrane porins of Klebsiella pneumoniae. We aimed to study the effect of combined porin loss and production of extended-spectrum β-lactamases (ESBLs) on imipenem susceptibility among K. pneumoniae clinical isolates. This study included 91 suspected ESBL-producing K. pneumoniae clinical isolates, isolated from different patient specimens at the Cairo University hospital from January to June 2010. All isolates were subjected to genotypic analysis of the outer membrane protein gene expression using reverse transcription-PCR (RT-PCR) and analysis of OmpK35/36 of 38 isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). By RT-PCR, loss of Omp35 was detected in 78 (85.7%) isolates, loss of Omp36 was detected in 64 (70.32%), and loss of both porins was detected in 62 (68.1%). Out of 91 isolates, 45 (49.5%) were resistant to cefoxitin, and 17 (18.7%) were confirmed as derepressed AmpC producers. Omp35 was lost in all FOX-resistant isolates, whereas Omp36 was lost in 42 (93.3%) (p-value 0.002). The mean of ceftazidime inhibition zone diameter was significantly decreased among ESBL-producing isolates with loss of Omp35/36 (p-value 0.041 and 0.006), respectively. The mean of imipenem minimal inhibitory concentration (MIC) was markedly increased to 8.55 μg/ml among AmpC-producing isolates with Omp35/36 loss, while the mean of imipenem MIC among the 66 confirmed ESBL producers was 0.32 μg/ml. Imipenem MIC was markedly increased among K. pneumoniae isolates showing AmpC production with loss of both porins OmpK35/36. Meanwhile, the association of porin OmpK35/36 loss with ESBL production was not a direct cause of resistance to imipenem.

High prevalence of non-clonal imipenem-nonsusceptible Enterobacter spp. isolates in Korea and their association with porin down-regulation.

PubMed

Lee, Ji-Young; Hong, Yoon-Kyoung; Lee, Haejeong; Ko, Kwan Soo

2017-01-01

We investigated the prevalence and clonal distribution of imipenem-nonsusceptible Enterobacter clinical isolates from hospitals in Korea and the contributions of various mechanisms to imipenem nonsusceptibility. The in vitro antimicrobial susceptibility to imipenem of 357 non-duplicated Enterobacter isolates obtained from eight geographically distant tertiary care hospitals in Korea was evaluated. Imipenem-nonsusceptible Enterobacter isolates were genotyped. Additionally, β-lactamase genes were screened using PCR, and the expression of efflux pump and porin genes was investigated using quantitative RT-PCR. A total of 31 isolates (8.7%) were not susceptible to imipenem. Clonal diversity of 17 imipenem-nonsusceptible E. cloacae isolates was demonstrated by multilocus sequence typing. Fourteen imipenem-nonsusceptible E. aerogenes isolates were found to be distantly genetically related by an ERIC-PCR analysis. Expression levels of porin ompD and ompK35 genes were decreased in all imipenem-nonsusceptible E. cloacae and E. aerogenes isolates. However, only two isolates were found positive for bla IMP and bla VIM genes, and expression of the efflux pump gene, acrB, was not associated with reduced imipenem susceptibility. Imipenem resistance seems to have occurred independently in most of the imipenem-nonsusceptible isolates in this study, and decreased porin expression was found to be the main mechanism underlying this reduced susceptibility to imipenem. Copyright © 2016 Elsevier Inc. All rights reserved.

Structure of Carbon Nanotube Porins in Lipid Bilayers: An in Situ Small-Angle X-ray Scattering (SAXS) Study [Atomic-level structure of carbon nanotube porins in lipid bilayers: an in-situ small-angle x-ray scattering (SAXS) study

DOE PAGES

Tran, Ich C.; Tunuguntla, Ramya H.; Kim, Kyunghoon; ...

2016-06-20

Carbon nanotube porins (CNTPs), small segments of carbon nanotubes capable of forming defined pores in lipid membranes, are important future components for bionanoelectronic devices as they could provide a robust analog of biological membrane channels. Furthermore, in order to control the incorporation of these CNT channels into lipid bilayers, it is important to understand the structure of the CNTPs before and after insertion into the lipid bilayer as well as the impact of such insertion on the bilayer structure. Here we employed a noninvasive in situ probe, small-angle X-ray scattering, to study the integration of CNT porins into dioleoylphosphatidylcholine bilayers.more » These results show that CNTPs in solution are stabilized by a monolayer of lipid molecules wrapped around their outer surface. We also demonstrate that insertion of CNTPs into the lipid bilayer results in decreased bilayer thickness with the magnitude of this effect increasing with the concentration of CNTPs.« less

Gonococcal Resistance to β-Lactams and Tetracycline Involves Mutation in Loop 3 of the Porin Encoded at the penB Locus

PubMed Central

Gill, M. J.; Simjee, S.; Al-Hattawi, K.; Robertson, B. D.; Easmon, C. S. F.; Ison, C. A.

1998-01-01

penB is a chromosomal mutation that confers resistance to β-lactams and tetracyclines and reduced susceptibility to quinolones in Neisseria gonorrhoeae. It is linked to the porin gene (por) and requires the increased expression of an efflux pump due to mtr. Transformation of a susceptible gonococcus (strain H1) with chromosomal DNA from strain FA140 (penA mtr penB; porin serovar IB1) and conjugal transfer of a β-lactamase-expressing plasmid was used to produce isogenic strains for determination of equilibrium periplasmic penicillin concentrations by the method of Zimmermann and Rosselet (W. Zimmermann and A. Rosselet, Antimicrob. Agents Chemother. 12:368–372, 1977). In transformants with the Mtr and PenB phenotypes, equilibrium concentrations of penicillin were reduced. DNA sequence analysis of por from isogenic penB and penB+ transformants revealed 14 sequence differences; nine of these differences resulted in amino acid changes. Three amino acid changes were found in the putative gonococcal equivalent of the pore-constricting loop 3 of Escherichia coli OmpF. Two of these changes (Gly-101–Ala-102→Asp-Asp) result in an increased negative charge at this position in por loop 3. PCR products comprising the complete por gene from strain FA140 were transformed into strain H1-2 (penA mtr; porin serovar IB-3), with the resulting transformants having the antibiotic susceptibility phenotype associated with penB. penB-like mutations were found in loop 3 of clinical isolates of gonococci with chromosomally mediated resistance to penicillin. We conclude that penB is a mutation in loop 3 of por that reduces porin permeability to hydrophilic antibiotics and plays an important role in the development of chromosomally mediated resistance to penicillin and tetracycline in gonococci. PMID:9797206

21 CFR 520.2325a - Sulfaquinoxaline drinking water.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) Chickens. (i) As an aid in the control of outbreaks of coccidiosis caused by Eimeria tenella, E. necatrix... not change litter unless absolutely necessary. Do not give flushing mashes. (3) Chickens and turkeys... sulfaquinoxaline and fowl typhoid caused by Salmonella gallinarum susceptible to sulfaquinoxaline. (ii) Administer...

21 CFR 520.2325a - Sulfaquinoxaline drinking water.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) Chickens. (i) As an aid in the control of outbreaks of coccidiosis caused by Eimeria tenella, E. necatrix... not change litter unless absolutely necessary. Do not give flushing mashes. (3) Chickens and turkeys... sulfaquinoxaline and fowl typhoid caused by Salmonella gallinarum susceptible to sulfaquinoxaline. (ii) Administer...

21 CFR 520.2325a - Sulfaquinoxaline drinking water.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) Chickens. (i) As an aid in the control of outbreaks of coccidiosis caused by Eimeria tenella, E. necatrix... not change litter unless absolutely necessary. Do not give flushing mashes. (3) Chickens and turkeys... sulfaquinoxaline and fowl typhoid caused by Salmonella gallinarum susceptible to sulfaquinoxaline. (ii) Administer...

OpnS, an outer membrane porin of Xenorhabdus nematophila, confers a competitive advantage for growth in the insect host.

PubMed

van der Hoeven, Ransome; Forst, Steven

2009-09-01

The gammaproteobacterium Xenorhabdus nematophila engages in a mutualistic association with an entomopathogenic nematode and also functions as a pathogen toward different insect hosts. We studied the role of the growth-phase-regulated outer membrane protein OpnS in host interactions. OpnS was shown to be a 16-stranded beta-barrel porin. opnS was expressed during growth in insect hemolymph and expression was elevated as the cell density increased. When wild-type and opnS deletion strains were coinjected into insects, the wild-type strain was predominantly recovered from the insect cadaver. Similarly, an opnS-complemented strain outcompeted the DeltaopnS strain. Coinjection of the wild-type and DeltaopnS strains together with uncolonized nematodes into insects resulted in nematode progeny that were almost exclusively colonized with the wild-type strain. Likewise, nematode progeny recovered after coinjection of a mixture of nematodes carrying either the wild-type or DeltaopnS strain were colonized by the wild-type strain. In addition, the DeltaopnS strain displayed a competitive growth defect when grown together with the wild-type strain in insect hemolymph but not in defined culture medium. The DeltaopnS strain displayed increased sensitivity to antimicrobial compounds, suggesting that deletion of OpnS affected the integrity of the outer membrane. These findings show that the OpnS porin confers a competitive advantage for the growth and/or the survival of X. nematophila in the insect host and provides a new model for studying the biological relevance of differential regulation of porins in a natural host environment.

STUDIES ON FOWL PARALYSIS (NEUROLYMPHOMATOSIS GALLINARUM)

PubMed Central

Pappenheimer, Alwin M.; Dunn, Leslie C.; Cone, Vernon

1929-01-01

1. Fowl paralysis (neurolymphomatosis gallinarum) is a disease entity, with characteristic clinical and pathological features. 2. The disease occurs in all parts of the United States, Holland, Austria and probably South America. 3. The disease appears to be endemic in certain foci. Having once appeared, the disease tends to persist through successive years. 4. It occurs with about equal frequency in both sexes; all common breeds may be affected. 5. Symptoms appear between the 3rd and 18th months. Typical clinical cases have not been observed outside of these limits. 6. The conspicuous symptoms are (a) asymmetrical, partial and progressive paralysis of the wings and both legs, and rarely of neck muscles; (b) occasional grey discoloration of iris, with blindness. Nutrition is usually preserved. 7. The duration is variable; the outcome is usually fatal, but spontaneous recovery may rarely occur. 8. The principal pathological changes are found in the nervous system. In the peripheral nerves, the essential feature is an intense infiltration of lymphoid, plasma cells, and large mononuclears. This is accompanied by a myelin degeneration in the more advanced lesions, but the cellular infiltrations appear to precede the degenerative changes. In brain, cord and meninges, there are similar infiltrations predominantly perivascular. Infiltrations of the iris with lymphoid and plasma cells are found in the cases showing gross discoloration of the iris. Visceral lymphomata, originating usually in the ovary, are associated in a certain percentage of the cases. Evidence is presented in favor of the view that this association is not accidental, and that the lymphomata are a manifestation of the disease. 9. Infiltrations of the spinal cord and brain, rarely of the peripheral nerves, are frequently present in birds showing no clinical symptoms. These are interpreted as mild cases of the same disease. 10. No microorganisms of etiological significance have been demonstrated in the

Purification, characterization and sequence analysis of Omp50,a new porin isolated from Campylobacter jejuni.

PubMed Central

Bolla, J M; Dé, E; Dorez, A; Pagès, J M

2000-01-01

A novel pore-forming protein identified in Campylobacter was purified by ion-exchange chromatography and named Omp50 according to both its molecular mass and its outer membrane localization. We observed a pore-forming ability of Omp50 after re-incorporation into artificial membranes. The protein induced cation-selective channels with major conductance values of 50-60 pS in 1 M NaCl. N-terminal sequencing allowed us to identify the predicted coding sequence Cj1170c from the Campylobacter jejuni genome database as the corresponding gene in the NCTC 11168 genome sequence. The gene, designated omp50, consists of a 1425 bp open reading frame encoding a deduced 453-amino acid protein with a calculated pI of 5.81 and a molecular mass of 51169.2 Da. The protein possessed a 20-amino acid leader sequence. No significant similarity was found between Omp50 and porin protein sequences already determined. Moreover, the protein showed only weak sequence identity with the major outer-membrane protein (MOMP) of Campylobacter, correlating with the absence of antigenic cross-reactivity between these two proteins. Omp50 is expressed in C. jejuni and Campylobacter lari but not in Campylobacter coli. The gene, however, was detected in all three species by PCR. According to its conformation and functional properties, the protein would belong to the family of outer-membrane monomeric porins. PMID:11104668

Role of the transmembrane domain of the VanT serine racemase in resistance to vancomycin in Enterococcus gallinarum BM4174.

PubMed

Arias, C A; Peña, J; Panesso, D; Reynolds, P

2003-03-01

Enterococcus gallinarum BM4175 (a vancomycin-susceptible derivative of BM4174 obtained by insertional inactivation of vanC-1) was transformed with plasmid constructs pCA10 (containing the genes necessary for resistance, vanC-1-XYc-T), pJP1 (with a fragment lacking the DNA encoding the transmembrane region of VanT, -vanC-1-XYc-T((Delta))(2-322)-) and with plasmids containing fragments encoding either the transmembrane (mvanT(1-322)) or racemase (svanT(323-698)) domains of VanT under the control of a constitutive promoter. Accumulated peptidoglycan precursors were measured in all strains in the presence of L-Ser, D-Ser (50 mM) or in the absence of any growth supplement. Uptake of 0.1 mM L-[(14)C]serine was also determined in BM4174, BM4175 and BM4175/pCA10. Vancomycin resistance was restored in BM4175 transformed with pCA10(C-1-XYc-T), and the profile of peptidoglycan precursors was similar to wild-type E. gallinarum BM4174. Transformation of E. gallinarum BM4175 with plasmid pJP1(vanC-1-XYc-T((Delta))(2-322)) resulted in: (i) vancomycin MICs remaining within susceptible levels (< or =4 mg/L) in the absence of any growth supplement, but increasing to 8 mg/L when either L-Ser or D-Ser was added to the medium; and (ii) the relative amounts of accumulated UDP-MurNAc-pentapeptide[D-Ser] and tetrapeptide precursors decreasing substantially compared with BM4175/pCA10 and BM4174. The effect on the appearance of tetrapeptide appeared to be host dependent, since a substantial amount was present when the same plasmid construct pJP1(vanC-1-XYc-T((Delta))(2-322)) was electroporated into Enterococcus faecalis JH2-2. The uptake of L-[(14)C]Ser at 240 s was decreased by approximately 40% in BM4175 compared with BM4174. Plasmid pCA10(C-1-XY(C)-T) restored uptake of L-[(14)C]Ser at 180 and 240 s in BM4175. The results suggest that the transmembrane domain of VanT is likely to be involved in the transport of L-Ser, and that in its absence the resistance phenotype is compromised.

Clonal background, resistance gene profile, and porin gene mutations modulate in vitro susceptibility to imipenem/relebactam in diverse Enterobacteriaceae.

PubMed

Gomez-Simmonds, Angela; Stump, Stephania; Giddins, Marla J; Annavajhala, Medini K; Uhlemann, Anne-Catrin

2018-06-11

Treatment options for carbapenem-resistant Enterobacteriaceae (CRE) are limited. While Klebsiella pneumoniae harboring bla KPC account for most CRE, recent evidence points to increasing diversification of CRE. We determined whether CRE species and antibiotic resistance genotype influence response to relebactam (REL), a novel beta-lactamase inhibitor with class A/C activity, combined with imipenem(IMI)/cilastatin. We carried out broth microdilution testing to IMI alone or in the presence of 4 μg/mL REL in 154 clinical isolates collected at a New York City hospital with high prevalence of bla KPC including Enterobacter spp. (n=96), K. pneumoniae (n=44), Escherichia coli (n=1), Serratia marcescens (n=9) and Citrobacter spp. (n=4). Resistance gene profiles and presence of major porin gene disruptions were ascertained by whole genome sequencing. Addition of REL decreased the IMI MIC to the susceptible range (≤1 μg/mL) in 88% of isolates. However, S. marcescens IMI/REL MICs were 4 to 8-fold higher than those of other organisms. Most bla KPC -positive isolates had IMI/REL MICs ≤1 μg/mL (88%), including E. cloacae ST171 (93%) and K. pneumoniae ST258 (82%). Nineteen isolates had IMI/REL MICs ≥2 μg/mL, of which 84% harbored bla KPC and one was bla NDM-1 -positive. Isolates with IMI/REL MICs ≥2 μg/mL versus ≤1 μg/mL were significantly more likely to demonstrate disruption of at least one porin gene (42% versus 19%, p =0.04), although most S. marcescens isolates (67%) had intact porin genes. In conclusion, while REL reduced IMI MICs in a majority of diverse CRE isolates including high-risk clones, chromosomal factors impacted IMI/REL susceptibilities and may contribute to elevated MICs in S. marcescens. Copyright © 2018 American Society for Microbiology.

OpnS, an Outer Membrane Porin of Xenorhabdus nematophila, Confers a Competitive Advantage for Growth in the Insect Host▿ †

PubMed Central

van der Hoeven, Ransome; Forst, Steven

2009-01-01

The gammaproteobacterium Xenorhabdus nematophila engages in a mutualistic association with an entomopathogenic nematode and also functions as a pathogen toward different insect hosts. We studied the role of the growth-phase-regulated outer membrane protein OpnS in host interactions. OpnS was shown to be a 16-stranded β-barrel porin. opnS was expressed during growth in insect hemolymph and expression was elevated as the cell density increased. When wild-type and opnS deletion strains were coinjected into insects, the wild-type strain was predominantly recovered from the insect cadaver. Similarly, an opnS-complemented strain outcompeted the ΔopnS strain. Coinjection of the wild-type and ΔopnS strains together with uncolonized nematodes into insects resulted in nematode progeny that were almost exclusively colonized with the wild-type strain. Likewise, nematode progeny recovered after coinjection of a mixture of nematodes carrying either the wild-type or ΔopnS strain were colonized by the wild-type strain. In addition, the ΔopnS strain displayed a competitive growth defect when grown together with the wild-type strain in insect hemolymph but not in defined culture medium. The ΔopnS strain displayed increased sensitivity to antimicrobial compounds, suggesting that deletion of OpnS affected the integrity of the outer membrane. These findings show that the OpnS porin confers a competitive advantage for the growth and/or the survival of X. nematophila in the insect host and provides a new model for studying the biological relevance of differential regulation of porins in a natural host environment. PMID:19465651

New functions of an old protein: the eukaryotic porin or voltage dependent anion selective channel (VDAC).

PubMed

De Pinto, Vito; Messina, Angela; Accardi, Rosita; Aiello, Rita; Guarino, Francesca; Tomasello, Marianna Flora; Tommasino, Massimo; Tasco, Gianluca; Casadio, Rita; Benz, Roland; De Giorgi, Francesca; Ichas, François; Baker, Mark; Lawen, Alfons

2003-03-01

Mitochondrial porin or VDAC (Voltage Dependent Anion selective Channels) was identified for the first time in 1976, on the basis of the evolutionary similarity between the gram negative and mitochondrial outer membranes. Since this achievement VDAC has been extensively investigated: its functional features have been sharply defined upon reconstitution in artificial membranes and its sequence has been determined in many genomes. Unfortunately the tertiary structure has not yet been solved, mainly because it proved to be very difficult to get suitable crystals. Despite this established knowledge, in the last few years this protein has attracted renewed interest. There are two main reasons for this interest: the discovery, in most eukaryotes, of a family of genes encoding VDAC isoforms and the claims of VDAC involvement in the intrinsic pathway of apoptosis and in particular in the mechanism of cytochrome c release from mitochondria. We can affirm that nowadays the eukaryotic porin (or VDAC) is studied in a more general cellular contest, looking at the interactions and integration with other molecules, since VDAC is in a crucial position in the cell, forming the main interface between the mitochondrial and the cellular metabolisms. In this minireview we will briefly focus our attention onto the following topics: 1) recent advances about the structure of VDAC; 2) the VDAC-related multigene families; 3) the presence, targeting and function of VDAC in various cell membranes.

Comparative Genomics of Enterococci: Variation in Enterococcus faecalis, Clade Structure in E. faecium, and Defining Characteristics of E. gallinarum and E. casseliflavus

PubMed Central

Palmer, Kelli L.; Godfrey, Paul; Griggs, Allison; Kos, Veronica N.; Zucker, Jeremy; Desjardins, Christopher; Cerqueira, Gustavo; Gevers, Dirk; Walker, Suzanne; Wortman, Jennifer; Feldgarden, Michael; Haas, Brian; Birren, Bruce; Gilmore, Michael S.

2012-01-01

ABSTRACT The enterococci are Gram-positive lactic acid bacteria that inhabit the gastrointestinal tracts of diverse hosts. However, Enterococcus faecium and E. faecalis have emerged as leading causes of multidrug-resistant hospital-acquired infections. The mechanism by which a well-adapted commensal evolved into a hospital pathogen is poorly understood. In this study, we examined high-quality draft genome data for evidence of key events in the evolution of the leading causes of enterococcal infections, including E. faecalis, E. faecium, E. casseliflavus, and E. gallinarum. We characterized two clades within what is currently classified as E. faecium and identified traits characteristic of each, including variation in operons for cell wall carbohydrate and putative capsule biosynthesis. We examined the extent of recombination between the two E. faecium clades and identified two strains with mosaic genomes. We determined the underlying genetics for the defining characteristics of the motile enterococci E. casseliflavus and E. gallinarum. Further, we identified species-specific traits that could be used to advance the detection of medically relevant enterococci and their identification to the species level. PMID:22354958

Interpretations of antibody responses to Salmonella enterica serotype enteritidis gm flagellin in poultry flocks are enhanced by a kinetics-based enzyme-linked immunosorbent assay.

PubMed

McDonough, P L; Jacobson, R H; Timoney, J F; Mutalib, A; Kradel, D C; Chang, Y F; Shin, S J; Lein, D H; Trock, S; Wheeler, K

1998-07-01

Many regulatory and diagnostic programs for the detection of Salmonella enterica serotype Enteritidis infection in commercial poultry flocks have relied on rapid Pullorum agglutination tests to screen birds because of the shared antigens of S. enterica Enteritidis and S. enterica Pullorum and Gallinarum; however, the use of the enzyme-linked immunosorbent assay (ELISA) format affords better analytical sensitivity than crude agglutination tests. In this study, we adapted our earlier conventional indirect ELISA, using gm flagellin as the antigen, to a kinetics-based, computer-controlled ELISA (KELA). The KELA was used to screen for flagellin antibody from three commercial flocks: (i) a large flock involved in a U.S. Department of Agriculture trace back from a human S. enterica Enteritidis foodborne outbreak (n = 3,209), (ii) a flock infected with the endemic S. enterica Enteritidis serotype but which also had multiple other Salmonella serotypes (n = 65), and (iii) an S. enterica Pullorum-infected flock (n = 12). The first flock (S. enterica Enteritidis prevalence of 2.45% based on culture) provided a field test of the KELA and allowed the calculation of diagnostic sensitivity (D-Sn) and diagnostic specificity (D-Sp). With a cutoff of 10 (used for screening flocks [i.e., high sensitivity]), the KELA has a D-Sn of 95.2% and a D-Sp of 18.5%; with a cutoff of 140 (used in confirmatory flock testing [i.e., high specificity]), the KELA has a D-Sn of 28.0% and a D-Sp of 99.1%. We found that with a cutoff of 60 (D-Sn = 63.1%; D-Sp = 91.6%), we could eliminate reactions in the KELA caused by other non-S. enterica Enteritidis salmonellae. The KELA was also compared to two commercial rapid Pullorum tests, the Solvay (D-Sn = 94.9%; D-Sp = 55.5%) and the Vineland (D-Sn = 62.0%; D-Sp = 75.3%).

[Salmonella].

PubMed

Amo, Kiyoko

2012-08-01

Nontyphoidal salmonella causes infectious gastroenteritis, and sometimes causes bacteremia and meningitis. Gastroenteritis associated with nontyphoidal salmonella, in which fever, diarrhea, vomiting and abdominal cramps, is a common disease. The major way of transmittion is food of animal origin, for example egg. That is the reason why precausion is so important such as wash hands before cooking, avoid eating raw egg and wash the cooking utensils after contact raw foods. In this report, I presented the rare severe case of encephalitis caused by salmonella infection.

High-Yield Synthesis and Optical Properties of Carbon Nanotube Porins

DOE PAGES

Tunuguntla, Ramya H.; Chen, Xi; Belliveau, Allison; ...

2017-01-18

Carbon nanotube porins (CNTPs) are a convenient membrane-based model system for studying nanofluidic transport that replicates a number of key structural features of biological membrane channels. We present a generalized approach for CNTP synthesis using sonochemistry-assisted segmenting of carbon nanotubes. Prolonged tip sonication in the presence of lipid molecules debundles and fragments long carbon nanotube aggregates into stable and water-soluble individual CNTPs with lengths in the range 5–20 nm. We discuss the main parameters that determine the efficiency and the yield of this process, describe the optimized conditions for high-yield CNTP synthesis, and demonstrate that this methodology can be adaptedmore » for synthesis of CNTPs of different diameters. We also present the optical properties of CNTPs and show that a combination of Raman and UV–vis–NIR spectroscopy can be used to monitor the quality of the CNTP synthesis. Altogether, CNTPs represent a versatile nanopore building block for creating higher-order functional biomimetic materials.« less

Effect of Porins and blaKPC Expression on Activity of Imipenem with Relebactam in Klebsiella pneumoniae: Can Antibiotic Combinations Overcome Resistance?

PubMed

Balabanian, Gregory; Rose, Michael; Manning, Nyla; Landman, David; Quale, John

2018-05-21

Imipenem with relebactam is a novel β-lactam-β-lactamase inhibitor that has activity against most KPC-producing Enterobacteriaceae. Using 10 isolates of KPC-possessing Klebsiella pneumoniae, we assessed the relationship between imipenem-relebactam minimum inhibitory concentrations (MICs) and mechanisms known to contribute to antimicrobial resistance. The effect of adding a second agent was assessed by time-kill experiments. Mutations affecting the genes encoding porins ompK35 and ompK36 and identification of β-lactamases were assessed by PCR. Expression of bla KPC and acrB was assessed by real-time reverse-transcriptase (RT)-PCR, and production of OmpK36 by SDS-PAGE. Time-kill studies were performed using combinations of imipenem-relebactam with polymyxin B, amikacin, or tigecycline. Seven isolates having a disruption in a single porin, or in neither porin, remained susceptible to imipenem-relebactam. The addition of a second agent did not improve the activity of imipenem-relebactam for these isolates, although the addition of tigecycline was antagonistic for three isolates. Three isolates had major disruptions in both ompK35 and ompK36 that correlated with reduced activity of imipenem-relebactam (MICs 2/4, 8/4, and 512/4 μg/mL). Two of these isolates also had overexpression of bla KPC , including the isolate with the highest MIC. These isolates were also resistant to polymyxin B and amikacin. The addition of amikacin provided both synergistic and bactericidal activity for the two more resistant isolates. The activity of imipenem-relebactam against K. pneumoniae is affected by major disruptions of both ompK35 and ompK36 and by expression of the KPC gene. Combining imipenem-relebactam with an aminoglycoside may be a promising approach for isolates with reduced susceptibility to imipenem-relebactam.

Comparison of CHROMagar Salmonella Medium and Xylose-Lysine-Desoxycholate and Salmonella-Shigella Agars for Isolation of Salmonella Strains from Stool Samples

PubMed Central

Maddocks, Susan; Olma, Tom; Chen, Sharon

2002-01-01

The growth and appearance of 115 stock Salmonella isolates on a new formulation of CHROMagar Salmonella (CAS) medium were compared to those on xylose-lysine-desoxycholate agar (XLD), Salmonella-Shigella agar (SS), and Hektoen enteric agar (HEA) media. CAS medium was then compared prospectively to XLD and SS for the detection and presumptive identification of Salmonella strains in 500 consecutive clinical stool samples. All stock Salmonella isolates produced typical mauve colonies on CAS medium. Nine Salmonella strains were isolated from clinical specimens. The sensitivities for the detection of salmonellae after primary plating on CAS medium and the combination of XLD and SS after enrichment were 100%. The specificity for the detection of salmonellae after primary plating on CAS medium (83%) was significantly (P < 0.0001) higher than that after primary plating on the combination of SS and XLD media (55%) (a 28% difference in rates; 95% confidence interval, 23.0 to 34%). Twenty-nine non-Salmonella organisms produced mauve colonies on CAS medium, including 17 Candida spp. (59%) and 8 Pseudomonas spp. (28%). These were easily excluded as salmonellae by colony morphology, microscopic examination of a wet preparation, or oxidase testing. One biochemically inert Escherichia coli isolate required further identification to differentiate it from Salmonella spp. The use of plating on CAS medium demonstrated high levels of sensitivity and specificity and reduced the time to final identification of Salmonella spp., resulting in substantial cost savings. It can be recommended for use for the primary isolation of Salmonella spp. from stool specimens. Other media (e.g., XLD) are required to detect Shigella spp. concurrently. PMID:12149365

Influence of On-farm pig Salmonella status on Salmonella Shedding at Slaughter.

PubMed

Casanova-Higes, A; Andrés-Barranco, S; Mainar-Jaime, R C

2017-08-01

The risk of Salmonella shedding among pigs at slaughter with regard to their previous on-farm Salmonella status was assessed in a group of pigs from a farm from NE of Spain. A total of 202 pigs that had been serologically monitored monthly during the fattening period and from which mesenteric lymph nodes (MLN) and faecal (SFEC) samples were collected at slaughter for Salmonella isolation were included. A repeated-measures anova was used to assess the relationship between mean OD% values during the fattening period and sampling time and bacteriology on MLN and SFEC. Pigs were also grouped into four groups, that is pigs seronegative during the fattening period and Salmonella negative in MLN (group A; n = 69); pigs seronegative during the fattening period but Salmonella positive in MLN (B; n = 36); pigs seropositive at least once and Salmonella positive in MLN (C; n = 50); and pigs seropositive at least once but Salmonella negative in (D; n = 47). Pigs shedding at slaughter seroconverted much earlier and showed much higher mean OD% values than non-shedders pigs. The proportion of Salmonella shedders in groups A and D was high and similar (26.1% and 29.8%, respectively), but significantly lower than that for groups B and C. The odds of shedding Salmonella for groups B and C were 4.8 (95% CI = 1.5-15.5) and 20.9 (3.7-118) times higher, respectively, when compared to A. It was concluded that a large proportion of Salmonella seronegative pigs may shed Salmonella at slaughter, which would be likely associated to previous exposure with contaminated environments (i.e. transport and lairage). For pigs already infected at farm, the likelihood of shedding Salmonella was much higher and may depend on whether the bacterium has colonized the MLN or not. The odds of shedding Salmonella spp. were always much higher for pigs in which Salmonella was isolated from MLN. © 2016 Blackwell Verlag GmbH.

Low-oxygen tensions found in Salmonella-infected gut tissue boost Salmonella replication in macrophages by impairing antimicrobial activity and augmenting Salmonella virulence.

PubMed

Jennewein, Jonas; Matuszak, Jasmin; Walter, Steffi; Felmy, Boas; Gendera, Kathrin; Schatz, Valentin; Nowottny, Monika; Liebsch, Gregor; Hensel, Michael; Hardt, Wolf-Dietrich; Gerlach, Roman G; Jantsch, Jonathan

2015-12-01

In Salmonella infection, the Salmonella pathogenicity island-2 (SPI-2)-encoded type three secretion system (T3SS2) is of key importance for systemic disease and survival in host cells. For instance, in the streptomycin-pretreated mouse model SPI-2-dependent Salmonella replication in lamina propria CD11c(-)CXCR1(-) monocytic phagocytes/macrophages (MΦ) is required for the development of colitis. In addition, containment of intracellular Salmonella in the gut critically depends on the antimicrobial effects of the phagocyte NADPH oxidase (PHOX), and possibly type 2 nitric oxide synthase (NOS2). For both antimicrobial enzyme complexes, oxygen is an essential substrate. However, the amount of available oxygen upon enteroinvasive Salmonella infection in the gut tissue and its impact on Salmonella-MΦ interactions was unknown. Therefore, we measured the gut tissue oxygen levels in a model of Salmonella enterocolitis using luminescence two-dimensional in vivo oxygen imaging. We found that gut tissue oxygen levels dropped from ∼78 Torr (∼11% O2) to values of ∼16 Torr (∼2% O2) during infection. Because in vivo virulence of Salmonella depends on the Salmonella survival in MΦ, Salmonella-MΦ interaction was analysed under such low oxygen values. These experiments revealed an increased intracellular replication and survival of wild-type and t3ss2 non-expressing Salmonella. These findings were paralleled by blunted nitric oxide and reactive oxygen species (ROS) production and reduced Salmonella ROS perception. In addition, hypoxia enhanced SPI-2 transcription and translocation of SPI-2-encoded virulence protein. Neither pharmacological blockade of PHOX and NOS2 nor impairment of T3SS2 virulence function alone mimicked the effect of hypoxia on Salmonella replication under normoxic conditions. However, if t3ss2 non-expressing Salmonella were used, hypoxia did not further enhance Salmonella recovery in a PHOX and NOS2-deficient situation. Hence, these data suggest that

Characterization and modelling of VanT: a novel, membrane-bound, serine racemase from vancomycin-resistant Enterococcus gallinarum BM4174.

PubMed

Arias, C A; Martín-Martinez, M; Blundell, T L; Arthur, M; Courvalin, P; Reynolds, P E

1999-03-01

Sequence determination of a region downstream from the vanXYc gene in Enterococcus gallinarum BM4174 revealed an open reading frame, designated vanT, that encodes a 698-amino-acid polypeptide with an amino-terminal domain containing 10 predicted transmembrane segments. The protein contained a highly conserved pyridoxal phosphate attachment site in the C-terminal domain, typical of alanine racemases. The protein was overexpressed in Escherichia coli, and serine racemase activity was detected in the membrane but not in the cytoplasmic fraction after centrifugation of sonicated cells, whereas alanine racemase activity was located almost exclusively in the cytoplasm. When the protein was overexpressed as a polypeptide lacking the predicted transmembrane domain, serine racemase activity was detected in the cytoplasm. The serine racemase activity was partially (64%) inhibited by D-cycloserine, whereas host alanine racemase activity was almost totally inhibited (97%). Serine racemase activity was also detected in membrane preparations of constitutively vancomycin-resistant E. gallinarum BM4174 but not in BM4175, in which insertional inactivation of the vanC-1 D-Ala:D-Ser ligase gene probably had a polar effect on expression of the vanXYc and vanT genes. Comparative modelling of the deduced C-terminal domain was based on the alignment of VanT with the Air alanine racemase from Bacillus stearothermophilus. The model revealed that almost all critical amino acids in the active site of Air were conserved in VanT, indicating that the C-terminal domain of VanT is likely to adopt a three-dimensional structure similar to that of Air and that the protein could exist as a dimer. These results indicate that the source of D-serine for peptidoglycan synthesis in vancomycin-resistant enterococci expressing the VanC phenotype involves racemization of L- to D-serine by a membrane-bound serine racemase.

High-level carbapenem resistance in a Klebsiella pneumoniae clinical isolate is due to the combination of bla(ACT-1) beta-lactamase production, porin OmpK35/36 insertional inactivation, and down-regulation of the phosphate transport porin phoe.

PubMed

Kaczmarek, Frank M; Dib-Hajj, Fadia; Shang, Wenchi; Gootz, Thomas D

2006-10-01

Clinical isolates of Klebsiella pneumoniae resistant to carbapenems and essentially all other antibiotics (multidrug resistant) are being isolated from some hospitals in New York City with increasing frequency. A highly related pair of K. pneumoniae strains isolated on the same day from one patient in a hospital in New York City were studied for antibiotic resistance. One (KP-2) was resistant to imipenem, meropenem, and sulopenem (MICs of 16 to 32 microg/ml) while the other (KP-1) was susceptible (MIC of 0.5 microg/ml); both contained the bla(ACT-1), bla(SHV-1), and bla(TEM-1) beta-lactamases. bla(ACT-1) in both strains was encoded on a large approximately 150-kb plasmid. Both isolates contained an identical class 1 integron encoding resistance to aminoglycosides and chloramphenicol. They each had identical insertions in ompK35 and ompK36, resulting in disruption of these key porin genes. The carbapenem-resistant and -susceptible isolates were extensively studied for differences in the structural and regulatory genes for the operons acrRAB, marORAB, romA-ramA, soxRS, micF, micC, phoE, phoBR, rpoS, and hfq. No changes were detected between the isolates except for a significant down-regulation of ompK37, phoB, and phoE in KP-2 as deduced from reverse transcription-PCR analysis of mRNA and polyacrylamide gel electrophoresis separation of outer membrane proteins. Backcross analysis was conducted using the wild-type phoE gene cloned into the vector pGEM under regulation of its native promoter as well as the lacZ promoter following transformation into the resistant KP-2 isolate. The wild-type gene reversed carbapenem resistance only when under control of the heterologous lacZ promoter. In the background of ompK35-ompK36 gene disruption, the up-regulation of phoE in KP-1 apparently compensated for porin loss and conferred carbapenem susceptibility. Down-regulation of phoE in KP-2 may represent the normal state of this gene, or it may have been selected from KP-1 in vivo

Novel efficient promoter of the mitochondrial porin, voltage-dependent anion channel (VDAC), in the genome of the Yarrowia lipolytica yeast.

PubMed

Kulanbaewa, F F; Sekova, V Yu; Isakova, E P; Deryabina, Y I; Nikolaev, A V

2016-09-01

This article presents the characteristics of the highly inducible promoter of the gene encoding the mitochondrial porin, the voltage-dependent anion channel (VDAC). This promoter is recommended for use in new genetic constructs both in basic research for assessing the adaptive strategy of lower eukaryotes under adverse conditions and in designing new highly competitive transformants producing economically important compounds (proteins, lipids, and organic acids) on its basis.

The fitness costs and trade-off shapes associated with the exclusion of nine antibiotics by OmpF porin channels.

PubMed

Phan, Katherine; Ferenci, Thomas

2017-06-01

The trade-off relationship between antibiotic exclusion and nutrient access across the Gram-negative outer membrane is determined by structural constraints in porin channels. The precise nutritional cost of exclusion is unknown for different antibiotics, as are the shapes of the nutrition-susceptibility trade-off. Using a library of 10 engineered isogenic Escherichia coli strains with structural modifications of OmpF porin expressed at a constant level, susceptibilities were measured for nine antibiotics and the nutritional fitness costs estimated by competitions in chemostats. Different antibiotics exhibited a remarkably varied range of geometries in the nutrition-susceptibility trade-off, including convex, concave and sigmoidal trade-off shapes. The trade-off patterns predict the possibility of adaptations in contributing to antibiotic resistance; exclusion of amoxicillin or trimethoprim in ompF mutants can occur with little loss of fitness whereas kanamycin and streptomycin exclusion has a high cost. Some individual OmpF changes even allow positive correlations (trade-ups), resulting in increased fitness and decreased susceptibility specifically to cephalexin or ciprofloxacin. The surprising plasticity of the nutrition-exclusion relationship means that there are no generalisable rules that apply to decreasing susceptibility for all antibiotics. The protein changes are exquisitely specific in determining nutritional fitness and adaptive outcomes in a structural constraint trade-off.

A trans-outer membrane porin-cytochrome protein complex for extracellular electron transfer by Geobacter sulfurreducens PCA

DOE PAGES

Liu, Yimo; Wang, Zheming; Liu, Juan; ...

2014-09-24

The multiheme, outer membrane c-type cytochrome (c-Cyt) OmcB of Geobacter sulfurreducens was previously proposed to mediate electron transfer across the outer membrane. However, the underlying mechanism has remained uncharacterized. In G. sulfurreducens, the omcB gene is part of two tandem four-gene clusters, each is predicted to encode a transcriptional factor (OrfR/OrfS), a porin-like outer membrane protein (OmbB/OmbC), a periplasmic c-type cytochrome (OmaB/OmaC), and an outer membrane c-Cyt (OmcB/OmcC), respectively. Here we showed that OmbB/OmbC, OmaB/OmaC and OmcB/OmcC of G. sulfurreducens PCA formed the porin-cytochrome (Pcc) protein complexes, which were involved in transferring electrons across the outer membrane. The isolated Pccmore » protein complexes reconstituted in proteoliposomes transferred electrons from reduced methyl viologen across the lipid bilayer of liposomes to Fe(III)-citrate and ferrihydrite. The pcc clusters were found in all eight sequenced Geobacter and 11 other bacterial genomes from six different phyla, demonstrating a widespread distribution of Pcc protein complexes in phylogenetically diverse bacteria. Deletion of ombB-omaB-omcB-orfS-ombC-omaC-omcC gene clusters had no impact on the growth of G. sulfurreducens PCA with fumarate, but diminished the ability of G. sulfurreducens PCA to reduce Fe(III)-citrate and ferrihydrite. Finally, complementation with the ombB-omaB-omcB gene cluster restored the ability of G. sulfurreducens PCA to reduce Fe(III)-citrate and ferrihydrite.« less

High-Level Carbapenem Resistance in a Klebsiella pneumoniae Clinical Isolate Is Due to the Combination of blaACT-1 β-Lactamase Production, Porin OmpK35/36 Insertional Inactivation, and Down-Regulation of the Phosphate Transport Porin PhoE

PubMed Central

Kaczmarek, Frank M.; Dib-Hajj, Fadia; Shang, Wenchi; Gootz, Thomas D.

2006-01-01

Clinical isolates of Klebsiella pneumoniae resistant to carbapenems and essentially all other antibiotics (multidrug resistant) are being isolated from some hospitals in New York City with increasing frequency. A highly related pair of K. pneumoniae strains isolated on the same day from one patient in a hospital in New York City were studied for antibiotic resistance. One (KP-2) was resistant to imipenem, meropenem, and sulopenem (MICs of 16 to 32 μg/ml) while the other (KP-1) was susceptible (MIC of 0.5 μg/ml); both contained the blaACT-1, blaSHV-1, and blaTEM-1 β-lactamases. blaACT-1 in both strains was encoded on a large ∼150-kb plasmid. Both isolates contained an identical class 1 integron encoding resistance to aminoglycosides and chloramphenicol. They each had identical insertions in ompK35 and ompK36, resulting in disruption of these key porin genes. The carbapenem-resistant and -susceptible isolates were extensively studied for differences in the structural and regulatory genes for the operons acrRAB, marORAB, romA-ramA, soxRS, micF, micC, phoE, phoBR, rpoS, and hfq. No changes were detected between the isolates except for a significant down-regulation of ompK37, phoB, and phoE in KP-2 as deduced from reverse transcription-PCR analysis of mRNA and polyacrylamide gel electrophoresis separation of outer membrane proteins. Backcross analysis was conducted using the wild-type phoE gene cloned into the vector pGEM under regulation of its native promoter as well as the lacZ promoter following transformation into the resistant KP-2 isolate. The wild-type gene reversed carbapenem resistance only when under control of the heterologous lacZ promoter. In the background of ompK35-ompK36 gene disruption, the up-regulation of phoE in KP-1 apparently compensated for porin loss and conferred carbapenem susceptibility. Down-regulation of phoE in KP-2 may represent the normal state of this gene, or it may have been selected from KP-1 in vivo under antibiotic pressure

Salmonella Infections in Childhood.

PubMed

Bula-Rudas, Fernando J; Rathore, Mobeen H; Maraqa, Nizar F

2015-08-01

Salmonella are gram-negative bacilli within the family Enterobacteriaceae. They are the cause of significant morbidity and mortality worldwide. Animals (pets) are an important reservoir for nontyphoidal Salmonella, whereas humans are the only natural host and reservoir for Salmonella Typhi. Salmonella infections are a major cause of gastroenteritis worldwide. They account for an estimated 2.8 billion cases of diarrheal disease each year. The transmission of Salmonella is frequently associated with the consumption of contaminated water and food of animal origin, and it is facilitated by conditions of poor hygiene. Nontyphoidal Salmonella infections have a worldwide distribution, whereas most typhoidal Salmonella infections in the United States are acquired abroad. In the United States, Salmonella is a common agent for food-borne–associated infections. Several outbreaks have been identified and are most commonly associated with agricultural products. Nontyphoidal Salmonella infection is usually characterized by a self-limited gastroenteritis in immunocompetent hosts in industrialized countries, but it may also cause invasive disease in vulnerable individuals (eg, children less than 1 year of age, immunocompromised). Antibiotic treatment is not recommended for treatment of mild to moderate gastroenteritis by nontyphoidal Salmonella in immunocompetent adults or children more than 1 year of age. Antibiotic treatment is recommended for nontyphoidal Salmonella infections in infants less than 3 months of age, because they are at higher risk for bacteremia and extraintestinal complications. Typhoid (enteric) fever and its potential complications have a significant impact on children, especially those who live in developing countries. Antibiotic treatment of typhoid fever has become challenging because of the emergence of Salmonella Typhi strains that are resistant to classically used first-line agents: ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol. The

Inactivation of Salmonella Senftenberg, Salmonella Typhimurium and Salmonella Tennessee in peanut butter by 915 MHz microwave heating.

PubMed

Song, Won-Jae; Kang, Dong-Hyun

2016-02-01

This study evaluated the efficacy of a 915 MHz microwave with 3 different levels to inactivate 3 serovars of Salmonella in peanut butter. Peanut butter inoculated with Salmonella enterica serovar Senftenberg, S. enterica serovar Typhimurium and S. enterica serovar Tennessee were treated with a 915 MHz microwave with 2, 4 and 6 kW and acid and peroxide values and color changes were determined after 5 min of microwave heating. Salmonella populations were reduced with increasing treatment time and treatment power. Six kW 915 MHz microwave treatment for 5 min reduced these three Salmonella serovars by 3.24-4.26 log CFU/g. Four and two kW 915 MHz microwave processing for 5 min reduced these Salmonella serovars by 1.14-1.48 and 0.15-0.42 log CFU/g, respectively. Microwave treatment did not affect acid, peroxide, or color values of peanut butter. These results demonstrate that 915 MHz microwave processing can be used as a control method for reducing Salmonella in peanut butter without producing quality deterioration. Copyright © 2015 Elsevier Ltd. All rights reserved.

The relationship between the numbers of Salmonella Enteritidis, Salmonella Heidelberg, or Salmonella Hadar colonizing reproductive tissues of experimentally infected laying hens and deposition inside eggs.

PubMed

Gast, Richard K; Guraya, Rupa; Guard, Jean; Holt, Peter S

2011-06-01

Contamination of eggs by Salmonella Enteritidis has been a prominent cause of human illness for several decades and is the focus of a recently implemented national regulatory plan for egg-producing flocks in the United States. Salmonella Heidelberg has also been identified as an egg-transmitted pathogen. The deposition of Salmonella strains inside eggs is a consequence of reproductive tract colonization in infected laying hens, but prior research has not determined the relationship between the numbers of Salmonella that colonize reproductive organs and the associated frequency of egg contamination. In the present study, groups of laying hens in two trials were experimentally infected with large oral doses of strains of Salmonella Enteritidis (phage type 13a), Salmonella Heidelberg, or Salmonella Hadar. Reproductive tissues of selected hens were cultured to detect and enumerate Salmonella at 5 days postinoculation, and the interior contents of eggs laid between 6 and 25 days postinoculation were tested for contamination. Significantly more internally contaminated eggs were laid by hens infected with Salmonella Enteritidis (3.58%) than with strains of either Salmonella Heidelberg (0.47%) or Salmonella Hadar (0%). However, no significant differences were observed between Salmonella strains in either isolation frequency or the number of colony-forming units (CFU) isolated from ovaries or oviducts. Salmonella isolation frequencies ranged from 20.8% to 41.7% for ovaries and from 8.3% to 33.3% for oviducts. Mean Salmonella colonization levels ranged from 0.10 to 0.51 log CFU/g for ovaries and from 0.25 to 0.46 log CFU/g for oviducts. Although parallel rank-orders were observed for Salmonella enumeration (in both ovaries and oviducts) and egg contamination frequency, a statistically significant relationship could not be established between these two parameters of infection.

Impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the broiler crop and ceca.

PubMed

Buhr, R J; Bourassa, D V; Hinton, A; Fairchild, B D; Ritz, C W

2017-12-01

Research was conducted to evaluate the impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the crop and ceca following feed withdrawal. In 4 experiments, pens of broilers in separate rooms were challenged with marker strains of either Salmonella Montevideo or Salmonella Heidelberg. Three d post challenge, a 12-hour feed withdrawal was initiated, and one pen of broilers was switched between rooms for each Salmonella serotype. In experiments 3 and 4, non-challenged broilers also were added to the Salmonella challenge pens. The litter of each pen was sampled before and after the feed withdrawal period, the broilers euthanized, and the crop and ceca aseptically removed for Salmonella isolation. Results showed that only the challenge Salmonella serotype was recovered from the litter in challenge pens where broilers were not moved, while both Salmonella serotypes were recovered from the litter of the switched pens. Salmonella was recovered from 56/80 crops and from 66/80 ceca of challenged broilers that remained in the challenge pens. The challenge Salmonella serotype was recovered from 50/80 crops and from 60/80 ceca, and the switched pens' litter Salmonella serotype was recovered from 19/80 crops but not from the ceca in broilers challenged with Salmonella and then switched between pens. For experiments 3 and 4, Salmonella was recovered from 19/40 crops and from only 2/40 ceca from the non-challenged broilers placed into the Salmonella challenge pens. The results from broilers that were switched between Salmonella challenge pens indicate that the recovery of Salmonella from the crop of broilers following feed withdrawal (on Salmonella-contaminated litter) appears to depend mainly on the initial challenge Salmonella (62%) and less on the litter Salmonella (24%) status during the feed withdrawal period. In contrast, only the initial challenge Salmonella was recovered from the ceca (79%) from broilers that remained in challenge pens or

Salmonella Infections (For Parents)

MedlinePlus

... iguanas). Another, rarer form — called Salmonella typhi — causes typhoid fever . What Is Salmonella Infection? Salmonella infection, or salmonellosis , ... More on this topic for: Parents Kids Teens Typhoid Fever E. Coli Stool Test: Bacteria Culture Food Safety ...

Purification, crystallization and preliminary X-ray analysis of aminoglycoside-2′′-phosphotransferase-Ic [APH(2′′)-Ic] from Enterococcus gallinarum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrnes, Laura J.; Badarau, Adriana; Vakulenko, Sergei B.

2008-02-01

APH(2′′)-Ic is an enzyme that is responsible for high-level gentamicin resistance in E. gallinarum isolates. Crystals of the wild-type enzyme and three mutants have been prepared and a complete X-ray diffraction data set was collected to 2.15 Å resolution from an F108L crystal. Bacterial resistance to aminoglycoside antibiotics is primarily the result of deactivation of the drugs. Three families of enzymes are responsible for this activity, with one such family being the aminoglycoside phosphotransferases (APHs). The gene encoding one of these enzymes, aminoglycoside-2′′-phosphotransferase-Ic [APH(2′′)-Ic] from Enterococcus gallinarum, has been cloned and the wild-type protein (comprising 308 amino-acid residues) and threemore » mutants that showed elevated minimum inhibitory concentrations towards gentamicin (F108L, H258L and a double mutant F108L/H258L) were expressed in Escherichia coli and subsequently purified. All APH(2′′)-Ic variants were crystallized in the presence of 14–20%(w/v) PEG 4000, 0.25 M MgCl{sub 2}, 0.1 M Tris–HCl pH 8.5 and 1 mM Mg{sub 2}GTP. The crystals belong to the monoclinic space group C2, with one molecule in the asymmetric unit. The approximate unit-cell parameters are a = 82.4, b = 54.2, c = 77.0 Å, β = 108.8°. X-ray diffraction data were collected to approximately 2.15 Å resolution from an F108L crystal at beamline BL9-2 at SSRL, Stanford, California, USA.« less

Interpretations of Antibody Responses to Salmonella enterica Serotype Enteritidis gm Flagellin in Poultry Flocks Are Enhanced by a Kinetics-Based Enzyme-Linked Immunosorbent Assay

PubMed Central

McDonough, Patrick L.; Jacobson, Richard H.; Timoney, John F.; Mutalib, Ahmed; Kradel, David C.; Chang, Yung-fu; Shin, Sang J.; Lein, Donald H.; Trock, Susan; Wheeler, Kaye

1998-01-01

Many regulatory and diagnostic programs for the detection of Salmonella enterica serotype Enteritidis infection in commercial poultry flocks have relied on rapid Pullorum agglutination tests to screen birds because of the shared antigens of S. enterica Enteritidis and S. enterica Pullorum and Gallinarum; however, the use of the enzyme-linked immunosorbent assay (ELISA) format affords better analytical sensitivity than crude agglutination tests. In this study, we adapted our earlier conventional indirect ELISA, using gm flagellin as the antigen, to a kinetics-based, computer-controlled ELISA (KELA). The KELA was used to screen for flagellin antibody from three commercial flocks: (i) a large flock involved in a U.S. Department of Agriculture trace back from a human S. enterica Enteritidis foodborne outbreak (n = 3,209), (ii) a flock infected with the endemic S. enterica Enteritidis serotype but which also had multiple other salmonella serotypes (n = 65), and (iii) an S. enterica Pullorum-infected flock (n = 12). The first flock (S. enterica Enteritidis prevalence of 2.45% based on culture) provided a field test of the KELA and allowed the calculation of diagnostic sensitivity (D-Sn) and diagnostic specificity (D-Sp). With a cutoff of 10 (used for screening flocks [i.e., high sensitivity]), the KELA has a D-Sn of 95.2% and a D-Sp of 18.5%; with a cutoff of 140 (used in confirmatory flock testing [i.e., high specificity]), the KELA has a D-Sn of 28.0% and a D-Sp of 99.1%. We found that with a cutoff of 60 (D-Sn = 63.1%; D-Sp = 91.6%), we could eliminate reactions in the KELA caused by other non-S. enterica Enteritidis salmonellae. The KELA was also compared to two commercial rapid Pullorum tests, the Solvay (D-Sn = 94.9%; D-Sp = 55.5%) and the Vineland (D-Sn = 62.0%; D-Sp = 75.3%). PMID:9665965

A serological survey for pathogens in old fancy chicken breeds in central and eastern part of The Netherlands.

PubMed

de Wit, J J; van Eck, J H; Crooijmans, R P; Pijpers, A

2004-05-15

To get an impression of the presence of pathogens in multi-aged flocks of old fancy chicken breeds in the Netherlands, plasma samples originating from 24 flocks were examined for antibodies against 17 chicken pathogens. These flocks were housed mainly in the centre and east of the Netherlands, regions with a high poultry density. The owners of the tested flocks showed their chicken at national and international poultry exhibitions. Antibodies against Avian Influenza, Egg Drop Syndrome '76 virus, Pox virus, Salmonella pullorum/gallinarum, Salmonella Enteritidis or Salmonella Typhimurium were not detected. However, antibodies against other Salmonella species, Mycoplasma gallisepticum, infectious bursal disease virus, infectious bronchitis virus, avian encephalomyelitis virus, chicken anaemia virus, infectious laryngotracheitis virus, and avian leukosis virus, subgroups A and B, and subgroup J were detected in a varying proportion of the flocks. This study shows that antibodies against many chicken pathogens are present among the flocks of old fancy chicken breeds that are exhibited at international poultry exhibitions.

Salmonella risk to consumers via pork is related to the Salmonella prevalence in pig feed.

PubMed

Rönnqvist, M; Välttilä, V; Ranta, J; Tuominen, P

2018-05-01

Pigs are an important source of human infections with Salmonella, one of the most common causes of sporadic gastrointestinal infections and foodborne outbreaks in the European region. Feed has been estimated to be a significant source of Salmonella in piggeries in countries of a low Salmonella prevalence. To estimate Salmonella risk to consumers via the pork production chain, including feed production, a quantitative risk assessment model was constructed. The Salmonella prevalence in feeds and in animals was estimated to be generally low in Finland, but the relative importance of feed as a source of Salmonella in pigs was estimated as potentially high. Discontinuation of the present strict Salmonella control could increase the risk of Salmonella in slaughter pigs and consequent infections in consumers. The increased use of low risk and controlled feed ingredients could result in a consistently lower residual contamination in pigs and help the tracing and control of the sources of infections. Copyright © 2017 Elsevier Ltd. All rights reserved.

Control of Salmonella enterica serovar Enteritidis in laying hens by inactivated Salmonella Enteritidis vaccines

PubMed Central

de Freitas Neto, Oliveiro Caetano; Mesquita, Aline Lopes; de Paiva, Jaqueline Boldrin; Zotesso, Fábio; Berchieri Júnior, Angelo

2008-01-01

Salmonella Enteritidis is one of the agents that is responsible for outbreaks of human foodborne salmonellosis caused by Salmonella Enteritidis and is generally associated with the consumption of poultry products. Inactivated Salmonella Enteritidis cell vaccine is one of the available methods to control Salmonella Enteritidis in breeders and laying hens, however results in terms of efficacy vary. This vaccine has never been tested in Brazil, therefore, the present work was carried out to assess three commercial inactivated Salmonella Enteritidis vaccines allowed in Brazil. Four hundred white light variety commercial laying hens were obtained at one-day-of age. At eight weeks old, the birds were divided into four groups with one hundred animals each. Birds from three groups (V1, V2 and V3) received different intramuscular vaccines, followed by a booster dose at 16 weeks of age. Birds from another group (CG) were not vaccinated. When the laying hens were 20, 25 and 31 weeks old, 13 from each group were transferred to another room and were challenged by inoculating 2 mL neat culture of Salmonella Enteritidis. On the second day after each challenge, the caecal contents, spleen, liver and ovary of three birds from each group were analyzed for the presence of Salmonella Enteritidis. Twice a week a cloacal swab of each bird was taken and all eggs laid were examined for the presence of Salmonella Enteritidis. After four consecutive negative cloacal swabs in all the groups, the birds were sacrificed so as to examine the liver, caecal contents and ovaries. Overall, the inactivated vaccine used in group V3 reduced Salmonella Enteritidis in the feces and eggs. A very small amount of Salmonella was found in the spleen, liver, ovary and caeca of the birds in the four groups during the whole experiment. In general, inactivated Salmonella Enteritidis vaccines was able to decrease the presence of Salmonella Enteritidis in the birds and in the eggs as well. Nevertheless, they must

Use of Attenuated but Metabolically Competent Salmonella as a Probiotic To Prevent or Treat Salmonella Infection

PubMed Central

Sabag-Daigle, Anice; Blunk, Henry M.; Gonzalez, Juan F.; Steidley, Brandi L.; Boyaka, Prosper N.

2016-01-01

Salmonella enterica is among the most burdensome of foodborne disease agents. There are over 2,600 serovars that cause a range of disease manifestations ranging from enterocolitis to typhoid fever. While there are two vaccines in use in humans to protect against typhoid fever, there are none that prevent enterocolitis. If vaccines preventing enterocolitis were to be developed, they would likely protect against only one or a few serovars. In this report, we tested the hypothesis that probiotic organisms could compete for the preferred nutrient sources of Salmonella and thus prevent or treat infection. To this end, we added the fra locus, which encodes a utilization pathway for the Salmonella-specific nutrient source fructose-asparagine (F-Asn), to the probiotic bacterium Escherichia coli Nissle 1917 (Nissle) to increase its ability to compete with Salmonella in mouse models. We also tested a metabolically competent, but avirulent, Salmonella enterica serovar Typhimurium mutant for its ability to compete with wild-type Salmonella. The modified Nissle strain became more virulent and less able to protect against Salmonella in some instances. On the other hand, the modified Salmonella strain was safe and effective in preventing infection with wild-type Salmonella. While we tested for efficacy only against Salmonella Typhimurium, the modified Salmonella strain may be able to compete metabolically with most, if not all, Salmonella serovars, representing a novel approach to control of this pathogen. PMID:27185789

Two Novel Salmonella Bivalent Vaccines Confer Dual Protection against Two Salmonella Serovars in Mice

PubMed Central

Zhao, Xinxin; Dai, Qinlong; Jia, Renyong; Zhu, Dekang; Liu, Mafeng; Wang, Mingshu; Chen, Shun; Sun, Kunfeng; Yang, Qiao; Wu, Ying; Cheng, Anchun

2017-01-01

Non-typhoidal Salmonella includes thousands of serovars that are leading causes of foodborne diarrheal illness worldwide. In this study, we constructed three bivalent vaccines for preventing both Salmonella Typhimurium and Salmonella Newport infections by using the aspartate semialdehyde dehydrogenase (Asd)-based balanced-lethal vector-host system. The constructed Asd+ plasmid pCZ11 carrying a subset of the Salmonella Newport O-antigen gene cluster including the wzx-wbaR-wbaL-wbaQ-wzy-wbaW-wbaZ genes was introduced into three Salmonella Typhimurium mutants: SLT19 (Δasd) with a smooth LPS phenotype, SLT20 (Δasd ΔrfbN) with a rough LPS phenotype, and SLT22 (Δasd ΔrfbN ΔpagL::T araC PBAD rfbN) with a smooth LPS phenotype when grown with arabinose. Immunoblotting demonstrated that SLT19 harboring pCZ11 [termed SLT19 (pCZ11)] co-expressed the homologous and heterologous O-antigens; SLT20 (pCZ11) exclusively expressed the heterologous O-antigen; and when arabinose was available, SLT22 (pCZ11) expressed both types of O-antigens, while in the absence of arabinose, SLT22 (pCZ11) expressed only the heterologous O-antigen. Exclusive expression of the heterologous O-antigen in Salmonella Typhimurium decreased the swimming ability of the bacterium and its susceptibility to polymyxin B. Next, the crp gene was deleted from the three recombinant strains for attenuation purposes, generating the three bivalent vaccine strains SLT25 (pCZ11), SLT26 (pCZ11), and SLT27 (pCZ11), respectively. Groups of BALB/c mice (12 mice/group) were orally immunized with 109 CFU of each vaccine strain twice at an interval of 4 weeks. Compared with a mock immunization, immunization with all three vaccine strains induced significant serum IgG responses against both Salmonella Typhimurium and Salmonella Newport LPS. The bacterial loads in the mouse tissues were significantly lower in the three vaccine-strain-immunized groups than in the mock group after either Salmonella Typhimurium or Salmonella

Phage-Coupled Piezoelectric Biodetector for Salmonella Typhimurium

DTIC Science & Technology

2005-08-01

protein. (POR) porin. (A) lipid A. (LPS) lipopolysaccharide (core polysaccharide and O-antigen). (F) fimbriae or flagella or pili...large protein and polysaccharide molecules in solution gave responses that did not correlate with mass changes imposed at the solid- liquid interface...chains, which are linked to lipid A via a genera-specific core polysaccharide . These 94 differences account for serotype specificity. To date, well over

Prevalence and Characterization of Salmonella enterica and Salmonella Bacteriophages Recovered from Beef Cattle Feedlots in South Texas.

PubMed

Xie, Yicheng; Savell, Jeffrey W; Arnold, Ashley N; Gehring, Kerri B; Gill, Jason J; Taylor, T Matthew

2016-08-01

Asymptomatic Salmonella carriage in beef cattle is a food safety concern, and the beef feedlot environment may function as a reservoir of this pathogen. The goal of this study was to identify and isolate Salmonella and Salmonella bacteriophages from beef cattle feedlot environments in order to better understand the microbial ecology of Salmonella and identify phages that might be useful as anti-Salmonella beef safety interventions. Three feedlots in south Texas were visited, and 27 distinct samples from each source were collected from dropped feces, feed from feed bunks, drinking water from troughs, and soil in cattle pens (n = 108 samples). Preenrichment, selective enrichment, and selective/differential isolation of Salmonella were performed on each sample. A representative subset of presumptive Salmonella isolates was prepared for biochemical identification and serotyping. Samples were pooled by feedlot and sample type to create 36 samples and enriched to recover phages. Recovered phages were tested for host range against two panels of Salmonella hosts. Salmonella bacteria were identified in 20 (18.5%) of 108 samples by biochemical and/or serological testing. The serovars recovered included Salmonella enterica serovars Anatum, Muenchen, Altona, Kralingen, Kentucky, and Montevideo; Salmonella Anatum was the most frequently recovered serotype. Phage-positive samples were distributed evenly over the three feedlots, suggesting that phage prevalence is not strongly correlated with the presence of culturable Salmonella. Phages were found more frequently in soil and feces than in feed and water samples. The recovery of bacteriophages in the Salmonella-free feedlot suggests that phages might play a role in suppressing the Salmonella population in a feedlot environment.

Screening for Salmonella in backyard chickens.

PubMed

Manning, Johanna; Gole, Vaibhav; Chousalkar, Kapil

2015-06-15

Salmonellosis is a significant zoonotic disease which has a considerable economic impact on the egg layer industry. There is limited information about the prevalence of Salmonella spp. in backyard chickens. The current study was conducted to determine the prevalence of Salmonella in backyard chickens, and the associated virulence of any serovars identified. Hundred and fifteen pooled samples from 30 backyard flocks in South Australia were screened. Four flocks tested positive for Salmonella spp. The overall Salmonella isolation rate in the current study was 10.4%. The estimated prevalence at individual bird level was 0.02% (95% CI 0.025-0.975). The serovars isolated were Salmonella Agona, Salmonella subsp 2 ser 21:z10:z6 (Wandsbek) and Salmonella Bovismorbificans. All Salmonella isolates tested positive for the prgH, orfL and spiC genes. The Salmonella subsp 2 ser 21:z10:z6 (Wandsbek) had the most antibiotic resistance, being resistant to ampicillin and cephalothin and having intermediate resistance to florphenicol. All of the Salmonella Agona had intermediate resistance to the ampicillin, while the Salmonella Bovismorbificans were susceptible to all antibiotics tested. With the increased interest of keeping backyard chickens, the current study highlights the zoonotic risk from Salmonella spp. associated with home flocks. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Prevalence of Salmonella in Australian reptiles.

PubMed

Scheelings, T Franciscus; Lightfoot, Dianne; Holz, Peter

2011-01-01

From January 2007 until June 2008, 504 reptiles of four families and 57 species were examined for Salmonella by using cloacal or intestinal swabs. Salmonella was identified in 139 (28%) of the 504 animals tested. Of the 504 reptiles examined, 210 were captive and 294 were wild. Ninety-eight (47%) of the captive reptiles were shedding Salmonella at the time of sampling. In contrast, only 41 (14%) of the wild reptiles were shedding Salmonella. The higher prevalence of Salmonella in captive reptiles was statistically significant (P<0.0001). No Salmonella was found in 60 wild, freshwater chelonians or 48 wild southern water skinks (Eulamprus heatwolei). Our results suggest that some species of wild reptiles in Australia are not natural carriers of Salmonella and that diet and captivity may influence Salmonella excretion in other species.

Oral immunisation of laying hens with the live vaccine strains of TAD Salmonella vac E and TAD Salmonella vac T reduces internal egg contamination with Salmonella Enteritidis.

PubMed

Gantois, Inne; Ducatelle, Richard; Timbermont, Leen; Boyen, Filip; Bohez, Lotte; Haesebrouck, Freddy; Pasmans, Frank; van Immerseel, Filip

2006-09-11

Eggs are a major source of human infections with Salmonella. Therefore controlling egg contamination in laying hen flocks is one of the main targets for control programmes. A study was carried out to assess the effect of oral vaccination with TAD Salmonella vac E, TAD Salmonella vac T and with both vaccines TAD Salmonella vac E and TAD Salmonella vac T, on colonization of the reproductive tract and internal egg contamination of laying hens with Salmonella Enteritidis. Three groups of 30 laying hens were vaccinated at 1 day, 6 weeks and 16 weeks of age with either one of the vaccine strains, or a combination of both vaccine strains, while a fourth group was left unvaccinated. At 24 weeks of age, the birds were intravenously challenged with 0.5 ml containing 5 x 10(7)cfu Salmonella Enteritidis PT4 S1400/94. The number of oviducts from which Salmonella was isolated, was significantly lower in the vaccinated than in the non-vaccinated hens at 3 weeks post-challenge. Significantly less egg contents were Salmonella positive in the birds vaccinated with TAD Salmonella vac E or TAD Salmonella vac T (12/105 batches of eggs in both groups) than in the unvaccinated birds (28/105 batches of eggs). Internal egg contamination in the hens vaccinated with both TAD Salmonella vac E and TAD Salmonella vac T was even more reduced, as over the whole experiment, only one batch of eggs was positive. In conclusion, these data indicate that vaccination of laying hens with these live vaccines could be considered as a valuable tool in controlling internal egg contamination.

The influence of different cucumariosides on immunogenicity of OmpF porin from Yersinia pseudotuberulosis as a model protein antigen of tubular immunostimulating complex

NASA Astrophysics Data System (ADS)

Sanina, N. M.; Chopenko, N. S.; Davydova, L. A.; Mazeika, A. N.; Portnyagina, O. Yu.; Kim, N. Yu.; Golotin, V. A.; Kostetsky, E. Y.; Shnyrov, V. L.

2017-09-01

Nanoparticulate tubular immunostimulating complex (TI-complex) is a novel promising adjuvant carrier of antigens allowing to create safe and effective vaccines of new generation. The adjuvant activity of TI-complexes based on monogalactosyldyacylglycerol (MGDG) from the sea alga Ulva lactuca and different triterpene glycosides cucumariosides (CDs) from marine invertebrate Cucumaria japonica and their fractions was studied to assess effects of different CDs on the immunogenicity of porin OmpF from Yersinia pseudotuberculosis (YOmpF). TI-complexes with cucumarioside A2-2 (CDA2-2) maximally stimulated anti-porin antibody production. Studies of protein intrinsic fluorescence showed that all CDs had a relaxing effect on the conformation of YOmpF, loosening peripheral region of protein and promoting exposure of the protein antigenic determinants to the water environment. The greatest immunostimulating effect of TI-complexes comprising CDA2-2 was accompanied by mild effect of this CD on the tertiary structure of protein antigen YOmpF, whereas cucumarioside E (CDE) and cucumarioside A2-4 (CDA2-4) caused especially sharp redistribution of spectral form of the YOmpF corresponding to the emission of an intrinsic protein fluorophore tryptophan.

vanC Cluster of Vancomycin-Resistant Enterococcus gallinarum BM4174

PubMed Central

Arias, Cesar A.; Courvalin, Patrice; Reynolds, Peter E.

2000-01-01

Glycopeptide-resistant enterococci of the VanC type synthesize UDP-muramyl-pentapeptide[d-Ser] for cell wall assembly and prevent synthesis of peptidoglycan precursors ending in d-Ala. The vanC cluster of Enterococcus gallinarum BM4174 consists of five genes: vanC-1, vanXYC, vanT, vanRC, and vanSC. Three genes are sufficient for resistance: vanC-1 encodes a ligase that synthesizes the dipeptide d-Ala-d-Ser for addition to UDP-MurNAc-tripeptide, vanXYC encodes a d,d-dipeptidase–carboxypeptidase that hydrolyzes d-Ala-d-Ala and removes d-Ala from UDP-MurNAc-pentapeptide[d-Ala], and vanT encodes a membrane-bound serine racemase that provides d-Ser for the synthetic pathway. The three genes are clustered: the start codons of vanXYC and vanT overlap the termination codons of vanC-1 and vanXYC, respectively. Two genes which encode proteins with homology to the VanS-VanR two-component regulatory system were present downstream from the resistance genes. The predicted amino acid sequence of VanRC exhibited 50% identity to VanR and 33% identity to VanRB. VanSC had 40% identity to VanS over a region of 308 amino acids and 24% identity to VanSB over a region of 285 amino acids. All residues with important functions in response regulators and histidine kinases were conserved in VanRC and VanSC, respectively. Induction experiments based on the determination of d,d-carboxypeptidase activity in cytoplasmic extracts confirmed that the genes were expressed constitutively. Using a promoter-probing vector, regions upstream from the resistance and regulatory genes were identified that have promoter activity. PMID:10817725

Broad-range (pan) Salmonella and Salmonella serotype typhi-specific real-time PCR assays: potential tools for the clinical microbiologist.

PubMed

Farrell, John J; Doyle, Laura J; Addison, Rachel M; Reller, L Barth; Hall, Geraldine S; Procop, Gary W

2005-03-01

We describe broad-range salmonellae (ie, Salmonella) and Salmonella serotype Typhi-specific LightCycler (Roche Diagnostics, Indianapolis, IN) real-time polymerase chain reaction assays. We validated these with a battery of 280 bacteria, 108 of which were salmonellae representing 20 serotypes. In addition, 298 isolates from 170 clinical specimens that were suspected to possibly represent Salmonella were tested with the pan- Salmonella assay. Finally, the pan-Salmonella assay also was used to test DNA extracts from 101 archived, frozen stool specimens, 55 of which were culture-positive for salmonellae. Both assays were 100% sensitive and specific when cultured isolates of the battery were tested. The pan- Salmonella assay also characterized correctly all salmonellae on the primary isolation agar and was 96% sensitive (53/55) and 96% specific (49/51) when nucleic acid extracts from direct stool specimens were tested. These assays represent potential tools the clinical microbiologist could use to screen suspect isolates or stool specimens for Salmonella.

Pathogenesis of Salmonellosis: Salmonella Exotoxins

DTIC Science & Technology

1982-03-08

Newport; Sal. 9633 - serotype Newport; and Sal. 9186 - serotype Newport. Salmonella enteritidis serotype typhimurium strain 2000 was obtained from...7054 Table 1I CULTURE MEDIA SURVEY Salmonella enteritidis Salmonella typhimurium serotype Javiana #10016 SRlI Culture Media C H 0 Cell Factor C H 0 Cell...C r AD REPORT NUMBER 2 0 Pathogenesis of Salmonellosis: Salmonella Exotoxins Annual Progress Report (9/1/78-9/1/79) Johnny W. Peterson, Ph.D. March 8

Salmonella, including antibiotic-resistant Salmonella, from flies captured from cattle farms in Georgia, U.S.A.

PubMed

Xu, Yumin; Tao, Sha; Hinkle, Nancy; Harrison, Mark; Chen, Jinru

2018-03-01

Flies can be transmission vehicles of Salmonella from cattle to humans. This study determined the prevalence of Salmonella in/on flies captured from 33 cattle farms, including 5 beef and 28 dairy farms, in Georgia, USA, and characterized antibiotic resistance profiles of the isolated Salmonella. Twenty-six out of the 33 cattle farms (79%) and 185 out of the 1650 flies (11%) tested positive for Salmonella in the study. The incidence of Salmonella-positive flies varied from farm to farm, ranging from 0 to 78%. Among the 185 Salmonella isolated from flies, 29% were resistant to ampicillin, 28% to tetracycline, 21% to amoxicillin/clavulanic acid, 20% to cefoxitin, and 12% to streptomycin. Incidences of resistance against other tested antibiotics were low, ranging from 0 to 3%. Furthermore, 28% of the Salmonella isolates were multidrug resistant, demonstrating resistance to 3 or more antibiotics. The minimal inhibitory concentrations of ampicillin, cefoxitin, streptomycin, and tetracycline against the Salmonella isolates ranged from 32 to >2048, 64 to 2048, 128 to 1024, and 32 to 1024μg/mL, respectively. These data suggest that flies could be effective vehicles of transmitting antibiotic resistant Salmonella and disseminating antibiotic resistance genes on cattle farms, posing risks to human and animal health. Copyright © 2017 Elsevier B.V. All rights reserved.

Surveillance of Salmonella prevalence in animal feeds and characterization of the Salmonella isolates by serotyping and antimicrobial susceptibility.

PubMed

Li, X; Bethune, L A; Jia, Y; Lovell, R A; Proescholdt, T A; Benz, S A; Schell, T C; Kaplan, G; McChesney, D G

2012-08-01

This article presents the surveillance data from the Feed Contaminants Program (2002-2009) and Salmonella Assignment (2007-2009) of the U.S. Food and Drug Administration (FDA), which monitor the trend of Salmonella contamination in animal feeds. A total of 2,058 samples were collected from complete animal feeds, feed ingredients, pet foods, pet treats, and supplements for pets in 2002-2009. These samples were tested for the presence of Salmonella. Those that were positive for Salmonella underwent serotyping and testing for antimicrobial susceptibility. Of the 2,058 samples, 257 were positive for Salmonella (12.5%). The results indicate a significant overall Salmonella reduction (p≤0.05) in animal feeds from 18.2% (187 samples tested) in 2002 to 8.0% (584 samples tested) in 2009. Among these samples, feed ingredients and pet foods/treats had the most significant reduction (p≤0.05). Of the 45 Salmonella serotypes identified, Salmonella Senftenberg and Salmonella Montevideo were the top two common serotypes (8.9%). Of the 257 Salmonella isolates obtained, 54 isolates (21%) were resistant to at least one antimicrobial. The findings provide the animal feed industries with Salmonella prevalence information that can be used to address Salmonella contamination problems. Our findings can also be used to educate pet owners when handling pet foods and treats at home to prevent salmonellosis.

Serine and alanine racemase activities of VanT: a protein necessary for vancomycin resistance in Enterococcus gallinarum BM4174.

PubMed

Arias, C A; Weisner, J; Blackburn, J M; Reynolds, P E

2000-07-01

Vancomycin resistance in Enterococcus gallinarum results from the production of UDP-MurNAc-pentapeptide[D-Ser]. VanT, a membrane-bound serine racemase, is one of three proteins essential for this resistance. To investigate the selectivity of racemization of L-Ser or L-Ala by VanT, a strain of Escherichia coli TKL-10 that requires D-Ala for growth at 42 degrees C was used as host for transformation experiments using plasmids containing the full-length vanT from Ent. gallinarum or the alanine racemase gene (alr) of Bacillus stearothermophilus: both plasmids were able to complement E. coli TKL-10 at 42 degrees C. No alanine or serine racemase activities were detected in the host strain E. coli TKL-10 grown at 30, 34 or 37 degrees C. Serine and alanine racemase activities were found almost exclusively (96%) in the membrane fraction of E. coli TKL-10/pCA4(vanT): the alanine racemase activity of VanT was 14% of the serine racemase activity in both E. coli TKL-10/pCA4(vanT) and E. coli XL-1 Blue/pCA4(vanT). Alanine racemase activity was present mainly (95%) in the cytoplasmic fraction of E. coli TKL-10/pJW40(alr), with a trace (1.6%) of serine racemase activity. Additionally, DNA encoding the soluble domain of VanT was cloned and expressed in E. coli M15 as a His-tagged polypeptide and purified: this polypeptide also exhibited both serine and alanine racemase activities; the latter was approximately 18% of the serine racemase activity, similar to that of the full-length, membrane-bound enzyme. N-terminal sequencing of the purified His-tagged polypeptide revealed a single amino acid sequence, indicating that the formation of heterodimers between subunits of His-tagged C-VanT and endogenous alanine racemases from E. coli was unlikely. The authors conclude that the membrane-bound serine racemase VanT also has alanine racemase activity but is able to racemize serine more efficiently than alanine, and that the cytoplasmic domain is responsible for the racemase activity.

Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin.

PubMed

Magro, Massimiliano; Fasolato, Luca; Bonaiuto, Emanuela; Andreani, Nadia Andrea; Baratella, Davide; Corraducci, Vittorino; Miotto, Giovanni; Cardazzo, Barbara; Vianello, Fabio

2016-10-01

Mineral iron(III) recognition by bacteria is considered a matter of debate. The peculiar surface chemistry of novel naked magnetic nanoparticles, called SAMNs (surface active maghemite nanoparticles) characterized by solvent exposed Fe(3+) sites on their surface, was exploited for studying mineral iron sensing in Pseudomonas fluorescens. SAMNs were applied for mimicking Fe(3+) ions in solution, acting as magnetically drivable probes to evaluate putative Fe(3+) recognition sites on the microorganism surface. Culture broths and nano-bio-conjugates were characterized by UV-Vis spectroscopy and mass spectrometry. The whole heritage of a membrane porin (OprF) of P. fluorescens Ps_22 cells was recognized and firmly bound by SAMNs. The binding of nanoparticles to OprF porin was correlated to a drastic inhibition of a siderophore (pyoverdine) biosynthesis and to the stimulation of the production and rate of formation of a secondary siderophore. The analysis of metabolic pathways, based on P. fluorescens Ps_22 genomic information, evidenced that this putative secondary siderophore does not belong to a selection of the most common siderophores. In the scenario of an adhesion mechanism, it is plausible to consider OprF as the biological component deputed to the mineral iron sensing in P. fluorescens Ps_22, as well as one key of siderophore regulation. The present work sheds light on mineral iron sensing in microorganisms. Peculiar colloidal naked iron oxide nanoparticles offer a useful approach for probing the adhesion of bacterial surface on mineral iron for the identification of the specific recognition site for this iron uptake regulation in microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

Recent Trends in Salmonella Outbreaks and Emerging Technology for Biocontrol of Salmonella Using Phages in Foods: A Review.

PubMed

Oh, Jun-Hyun; Park, Mi-Kyung

2017-12-28

Salmonella is one of the principal causes of foodborne outbreaks. As traditional control methods have shown less efficacy against emerging Salmonella serotypes or antimicrobialresistant Salmonella , new approaches have been attempted. The use of lytic phages for the biocontrol of Salmonella in the food industry has become an attractive method owing to the many advantages offered by the use of phages as biocontrol agents. Phages are natural alternatives to traditional antimicrobial agents; they have proven effective in the control of bacterial pathogens in the food industry, which has led to the development of different phage products. The treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases, and ultimately promotes safe environments for animal and plant food production, processing, and handling. After an extensive investigation of the current literature, this review focuses predominantly on the efficacy of phages for the successful control of Salmonella spp. in foods. This review also addresses the current knowledge on the pathogenic characteristics of Salmonella , the prevalence of emerging Salmonella outbreaks, the isolation and characterization of Salmonella -specific phages, the effectiveness of Salmonella -specific phages as biocontrol agents, and the prospective use of Salmonella -specific phages in the food industry.

Assessment of attenuated Salmonella vaccine strains in controlling experimental Salmonella Typhimurium infection in chickens

PubMed Central

Pei, Yanlong; Parreira, Valeria R.; Roland, Kenneth L.; Curtiss, Roy; Prescott, John F.

2014-01-01

Salmonella hold considerable promise as vaccine delivery vectors for heterologous antigens in chickens. Such vaccines have the potential additional benefit of also controlling Salmonella infection in immunized birds. As a way of selecting attenuated strains with optimal immunogenic potential as antigen delivery vectors, this study screened 20 novel Salmonella Typhimurium vaccine strains, differing in mutations associated with delayed antigen synthesis and delayed attenuation, for their efficacy in controlling colonization by virulent Salmonella Typhimurium, as well as for their persistence in the intestine and the spleen. Marked differences were observed between strains in these characteristics, which provide the basis for selection for further study as vaccine vectors. PMID:24396177

Assessment of attenuated Salmonella vaccine strains in controlling experimental Salmonella Typhimurium infection in chickens.

PubMed

Pei, Yanlong; Parreira, Valeria R; Roland, Kenneth L; Curtiss, Roy; Prescott, John F

2014-01-01

Salmonella hold considerable promise as vaccine delivery vectors for heterologous antigens in chickens. Such vaccines have the potential additional benefit of also controlling Salmonella infection in immunized birds. As a way of selecting attenuated strains with optimal immunogenic potential as antigen delivery vectors, this study screened 20 novel Salmonella Typhimurium vaccine strains, differing in mutations associated with delayed antigen synthesis and delayed attenuation, for their efficacy in controlling colonization by virulent Salmonella Typhimurium, as well as for their persistence in the intestine and the spleen. Marked differences were observed between strains in these characteristics, which provide the basis for selection for further study as vaccine vectors.

PREVALENCE OF SALMONELLA IN CAPTIVE REPTILES FROM CROATIA.

PubMed

Lukac, Maja; Pedersen, Karl; Prukner-Radovcic, Estella

2015-06-01

Salmonellosis transmitted by pet reptiles is an increasing public health issue worldwide. The aim of this study was to investigate the prevalence of Salmonella strains from captive reptiles in Croatia. From November 2009 to November 2011 a total of 292 skin, pharyngeal, cloacal, and fecal samples from 200 apparently healthy reptiles were tested for Salmonella excretions by bacteriologic culture and serotyping. These 200 individual reptiles included 31 lizards, 79 chelonians, and 90 snakes belonging to private owners or housed at the Zagreb Zoo, Croatia. Salmonella was detected in a total of 13% of the animals, among them 48.4% lizards, 8.9% snakes, and 3.8% turtles. Representatives of five of the six Salmonella enterica subspecies were identified with the following proportions in the total number of isolates: Salmonella enterica enterica 34.6%, Salmonella enterica houtenae 23.1%, Salmonella enterica arizonae 23.1%, Salmonella enterica diarizonae 15.4%, and Salmonella enterica salamae 3.8%. The 14 different serovars isolated included several rarely occurring serovars such as Salmonella Apapa, Salmonella Halle, Salmonella Kisarawe, and Salmonella Potengi. These findings confirm that the prevalence of Salmonella is considerable in captive reptiles in Croatia, indicating that these animals may harbor serovars not commonly seen in veterinary or human microbiologic practice. This should be addressed in the prevention and diagnostics of human reptile-transmitted infections.

Genetic relatedness of a rarely isolated Salmonella: Salmonella enterica serotype Niakhar from NARMS animal isolates.

PubMed

Tankson, J D; Fedorka-Cray, P J; Jackson, C R; Headrick, M

2006-02-01

In the United States, Salmonella enterica serotype Niakhar is infrequently isolated. Between 1997 and 2000, the animal arm of the National Antimicrobial Resistance Monitoring System-Enteric Bacteria (NARMS) assayed a total of 22,383 Salmonella isolates from various animal sources (swine, cattle, chickens, turkeys, cats, horses, exotics and dogs) for antimicrobial susceptibility. Isolates originated from diagnostic and non-diagnostic submissions. To study the phenotypic and genotypic characteristics of Salmonella Niakhar. Only five (0.02%) of the 22,383 isolates were identified as Salmonella Niakhar. Antimicrobial resistance testing indicated that three isolates were pan-susceptible, one isolate was resistant to ampicillin and one isolate was resistant to ampicillin, chloramphenicol, ciprofloxacin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline and trimethoprim/sulfamethoxazole. RAPD-PCR analysis, PFGE and ribotyping indicated that two pan-susceptible isolates were genetically similar, whereas the three remaining isolates were genetically different. The one Salmonella Niakhar isolate that was multiresistant harboured a class I integron, intI1 and two large plasmids. This study represents the first report of a ciprofloxacin-resistant Salmonella isolate from the animal arm of NARMS.

Farm-level associations with the shedding of Salmonella and antimicrobial-resistant Salmonella in U.S. dairy cattle.

PubMed

Habing, Greg G; Lombard, Jason E; Kopral, Christine A; Dargatz, David A; Kaneene, John B

2012-09-01

Salmonella enterica is the leading cause of foodborne-related deaths and hospitalizations within the United States. Infections caused by antimicrobial-resistant (AMR) strains are associated with higher hospital costs and case fatality. The objective for this study was to determine the association of management practices with the recovery of Salmonella and AMR Salmonella on dairy herds. Individual adult cow fecal samples and/or composite fecal samples were collected from 265 dairy herds in 17 states. Samples were cultured for Salmonella, and the MIC was determined for 15 antimicrobials. Herds were classified as Salmonella positive if at least one isolate was recovered, and AMR Salmonella positive if at least one resistant isolate was recovered. Questionnaires regarding management practices were administered to herd operators, and a subset of practices was selected based on subject knowledge and prior research. Data on preventive and therapeutic antimicrobial usage were included in the analysis. Logistic regression models were used to determine which practices were significantly (p<0.05) associated with each herd classification. A total of 124 and 25 herds were classified as Salmonella positive and AMR Salmonella positive, respectively. Variables significantly associated with Salmonella-positive herds included using sprinklers or misters for heat abatement (OR=2.8; CI: 1.6-4.9), feeding anionic salts to cows (OR=1.9; CI: 1.1-3.5), and feeding ionophores to cows (OR=2.1; CI: 1.2-3.7). Herds that used a broadcast/solid spread had lower odds (OR=0.26; CI: 0.11-0.63) of being Salmonella positive. Herds with at least one resistant isolate were more likely to have used composted/dried manure for bedding relative to herds with only susceptible isolates (OR=3.6; CI: 1.2-11.0). These results can be useful to focus additional research aimed at decreasing the prevalence of Salmonella and AMR Salmonella on U.S. dairy herds.

Detection of Salmonellae in the Environment

PubMed Central

Thomason, Berenice M.; Biddle, James W.; Cherry, William B.

1975-01-01

The incidence of salmonellae in contrasting environments was compared in this study. Samples collected from or near surface waters in a lush hardwood forest yielded four salmonellae serotypes from six culturally positive samples. A total of 76 samples collected from the top of a granite outcropping over a 3-month period yielded 10 positive samples. Only two salmonellae serotypes were isolated, and one of these was isolated only once. The nature of the sample material had no significant effect on the detection of salmonellae from the two sampling sites. However, the presence or absence of visible moisture in the sample significantly affected the recovery of salmonellae. The results showed that even a harsh environment such as that found on top of Stone Mountain may serve as an ecological niche for the survival and transmission of salmonellae. PMID:1106319

Salmonella Infections - Multiple Languages

MedlinePlus

... Are Here: Home → Multiple Languages → All Health Topics → Salmonella Infections URL of this page: https://medlineplus.gov/ ... V W XYZ List of All Topics All Salmonella Infections - Multiple Languages To use the sharing features ...

Fecal shedding of Salmonella in exotic felids.

PubMed

Clyde, V L; Ramsay, E C; Bemis, D A

1997-06-01

Two collections of exotic felids were screened for the presence of Salmonella by selective fecal culture utilizing selenite broth and Hektoen enteric agar. In > 90% of the samples, Salmonella was isolated from a single culture. A commercial horsemeat-based diet was fed in both collections, and one collection also was fed raw chicken. Salmonella was cultured from the raw chicken and the horsemeat diet for both collections. Multiple Salmonella serotypes were identified, with S. typhimurium and S. typhimurium (copenhagen) isolated most frequently. Approximately half of the Salmonella isolates demonstrated multiple antibiotic resistance. The ability to harbor Salmonella as normal nonpathogenic bacteria of the gastrointestinal tract may be a physiological adaptation to carnivory. The high rate of fecal shedding of Salmonella in healthy individuals clouds the interpretation of a positive fecal culture in an ill felid, or one with diarrhea. All zoo employees having contact with cat feces or raw diets have a high rate of occupational exposure to Salmonella and should exercise appropriate hygienic precautions.

Survival of Salmonella Newport in oysters.

PubMed

Morrison, Christopher M; Armstrong, Alexandra E; Evans, Sanford; Mild, Rita M; Langdon, Christopher J; Joens, Lynn A

2011-08-02

Salmonella enterica is the leading cause of laboratory-confirmed foodborne illness in the United States and raw shellfish consumption is a commonly implicated source of gastrointestinal pathogens. A 2005 epidemiological study done in our laboratory by Brands et al., showed that oysters in the United States are contaminated with Salmonella, and in particular, a specific strain of the Newport serovar. This work sought to further investigate the host-microbe interactions between Salmonella Newport and oysters. A procedure was developed to reliably and repeatedly expose oysters to enteric bacteria and quantify the subsequent levels of bacterial survival. The results show that 10 days after an exposure to Salmonella Newport, an average concentration of 3.7 × 10(3)CFU/g remains within the oyster meat, and even after 60 days there still can be more than 10(2)CFU/g remaining. However, the strain of Newport that predominated in the market survey done by Brands et al. does not survive within oysters or the estuarine environment better than any other strains of Salmonella we tested. Using this same methodology, we compared Salmonella Newport's ability to survive within oysters to a non-pathogenic strain of E. coli and found that after 10 days the concentration of Salmonella was 200-times greater than that of E. coli. We also compared those same strains of Salmonella and E. coli in a depuration process to determine if a constant 120 L/h flux of clean seawater could significantly reduce the concentration of bacteria within oysters and found that after 3 days the oysters retained over 10(4)CFU/g of Salmonella while the oysters exposed to the non-pathogenic strain of E. coli contained 100-times less bacteria. Overall, the results of this study demonstrate that any of the clinically relevant serovars of Salmonella can survive within oysters for significant periods of time after just one exposure event. Based on the drastic differences in survivability between Salmonella and a non

Performance of the chromID Salmonella Elite chromogenic agar in comparison with CHROMagar™ Salmonella, Oxoid™ Brilliance™ Salmonella and Hektoen agars for the isolation of Salmonella from stool specimens.

PubMed

Martiny, Delphine; Dediste, Anne; Anglade, Claire; Vlaes, Linda; Moens, Catherine; Mohamed, Souad; Vandenberg, Olivier

2016-10-01

chromID™ Salmonella Elite is compared with 3 culture media commonly used for Salmonella isolation from stool specimens. As results were equivalent to other chromogenic media (100% sensitivity, 98% specificity), only financial arguments should guide the choice for a medium with respect to another. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of VIDAS Salmonella (SLM) easy Salmonella method for the detection of Salmonella in a variety of foods: collaborative study.

PubMed

Crowley, Erin; Bird, Patrick; Fisher, Kiel; Goetz, Katherine; Benzinger, M Joseph; Agin, James; Goins, David; Johnson, Ronald L

2011-01-01

The VIDAS Salmonella (SLM) Easy Salmonella method is a specific enzyme-linked fluorescent immunoassay performed in the automated VIDAS instrument. The VIDAS Easy Salmonella method is a simple 2-step enrichment procedure, using pre-enrichment followed by selective enrichment in a newly formulated broth, SX2 broth. This new method was compared in a multilaboratory collaborative study to the U.S. Food and Drug Administration's Bacteriological Analytical Manual, Chapter 5 method for five food matrixes (liquid egg, vanilla ice cream, spinach, raw shrimp, and peanut butter) and the U.S. Department of Agriculture's Microbiology Laboratory Guidebook 4.04 method for deli turkey. Each food type was artificially contaminated with Salmonella at three inoculation levels. A total of 15 laboratories representing government, academia, and industry, throughout the United States, participated. In this study, 1583 samples were analyzed, of which 792 were paired replicates and 791 were unpaired replicates. Of the 792 paired replicates, 285 were positive by both the VIDAS and reference methods. Of the 791 unpaired replicates, 341 were positive by the VIDAS method and 325 were positive by the cultural reference method. A Chi-square analysis of each of the six food types was performed at the three inoculation levels tested. For all foods evaluated, the VIDAS Easy SLM method demonstrated results comparable to those of the reference methods for the detection of Salmonella.

Vaccines against invasive Salmonella disease

PubMed Central

MacLennan, Calman A; Martin, Laura B; Micoli, Francesca

2014-01-01

Though primarily enteric pathogens, Salmonellae are responsible for a considerable yet under-appreciated global burden of invasive disease. In South and South-East Asia, this manifests as enteric fever caused by serovars Typhi and Paratyphi A. In sub-Saharan Africa, a similar disease burden results from invasive nontyphoidal Salmonellae, principally serovars Typhimurium and Enteritidis. The existing Ty21a live-attenuated and Vi capsular polysaccharide vaccines target S. Typhi and are not effective in young children where the burden of invasive Salmonella disease is highest. After years of lack of investment in new Salmonella vaccines, recent times have seen increased interest in the area led by emerging-market manufacturers, global health vaccine institutes and academic partners. New glycoconjugate vaccines against S. Typhi are becoming available with similar vaccines against other invasive serovars in development. With other new vaccines under investigation, including live-attenuated, protein-based and GMMA vaccines, now is an exciting time for the Salmonella vaccine field. PMID:24804797

Characterizing Salmonella Contamination in Two Rendering Processing Plants.

PubMed

Gong, Chao; Jiang, Xiuping

2017-02-01

A microbiological investigation on Salmonella contamination was conducted in two U.S. rendering plants to investigate the potential cross-contamination of Salmonella in the rendering processing environment. Sampling locations were predetermined at the areas where Salmonella contamination may potentially occur, including raw materials receiving, crax (rendered materials before grinding process) grinding, and finished meal loading-out areas. Salmonella was either enumerated directly on xylose lysine Tergitol 4 agar plates or enriched in Rappaport-Vassiliadis and tetrathionate broths. The presumptive Salmonella isolates were confirmed using CHROMagar plating and latex agglutination testing and then characterized using pulsed-field gel electrophoresis, serotyping, and biofilm-forming determination. Among 108 samples analyzed, 79 (73%) samples were Salmonella positive after enrichment. Selected Salmonella isolates (n = 65) were assigned to 31 unique pulsed-field gel electrophoresis patterns, with 16 Salmonella serotypes, including Typhimurium and Mbandaka, identified as predominant serotypes and 10 Salmonella strains determined as strong biofilm formers. Our results indicated that the raw materials receiving area was the primary source of Salmonella and that the surfaces surrounding crax grinding and finished meal loading-out areas harbor Salmonella in biofilms that may recontaminate the finished meals. The same Salmonella serotypes found in both raw materials receiving and the finished meal loading-out areas suggested a potential of cross-contamination between different areas in the rendering processing environment.

Pathogenesis of Salmonellosis: Salmonella Exotoxins

DTIC Science & Technology

1982-03-08

of Salmonella enteritidis , which included 9630 serotype newport, 9136 serotype newport, 10016 serotype javiana, and 8832, serotype javiana were also...supplied by Dr. T. Huber. Additionally, four clinical isolates of Salmonella enteritidis , which included 986 serotype typhimurium, 2000 serotype...77Z7I AD _ REPORT NUMBER 3 0 Pathogenesis of Salmonellosis: Salmonella Exotoxins Annual Progress Report (9/1/79-8/31/80) M Johnny W. Peterson, Ph.D

Pathogenesis of Salmonellosis: Salmonella Exotoxins

DTIC Science & Technology

1982-03-08

membrane-as3ociated enterotowin produced by S. enteritidis and by S. typhimurium ; however they could find no similarities between their Salmonella ...AD. . 0 REPORT NUJMBER 1 Pathogenesis of Salmoneiliosis: Salmonella Exotoxins Annual Progress Report (12/1/77-9/1/78) Johnny W. Peterson. Ph.D. March...TYPE OF REPORT & PERIOD COVEREOD",- Uathogenesis of ,Salmonellosils: Salmonella Annual Progress Report Exotoxins 12/T/77 9/1/78 C. PERFORMCNG ORG

Impact of litter salmonella status during feed withdrawal on salmonella recovery from the broiler crop and ceca

USDA-ARS?s Scientific Manuscript database

Research was conducted to evaluate the impact of litter Salmonella status during feed withdrawal on Salmonella recovery from the crop and ceca following feed withdrawal. In 4 experiments, pens of broilers in separate rooms were challenged with marker strains of either Salmonella Montevideo or Salmon...

Paradigm Diagnostics Salmonella Indicator Broth (PDX-SIB) for detection of Salmonella on selected environmental surfaces.

PubMed

Olstein, Alan; Griffith, Leena; Feirtag, Joellen; Pearson, Nicole

2013-01-01

The Paradigm Diagnostics Salmonella Indicator Broth (PDX-SIB) is intended as a single-step selective enrichment indicator broth to be used as a simple screening test for the presence of Salmonella spp. in environmental samples. This method permits the end user to avoid multistep sample processing to identify presumptively positive samples, as exemplified by standard U.S. reference methods. PDX-SIB permits the outgrowth of Salmonella while inhibiting the growth of competitive Gram-negative and -positive microflora. Growth of Salmonella-positive cultures results in a visual color change of the medium from purple to yellow when the sample is grown at 37 +/- 1 degree C. Performance of PDX-SIB has been evaluated in five different categories: inclusivity-exclusivity, methods comparison, ruggedness, lot-to-lot variability, and shelf stability. The inclusivity panel included 100 different Salmonella serovars, 98 of which were SIB-positive during the 30 to 48 h incubation period. The exclusivity panel included 33 different non-Salmonella microorganisms, 31 of which were SIB-negative during the incubation period. Methods comparison studies included four different surfaces: S. Newport on plastic, S. Anatum on sealed concrete, S. Abaetetuba on ceramic tile, and S. Typhimurium in the presence of 1 log excess of Citrobacter freundii. Results of the methods comparison studies demonstrated no statistical difference between the SIB method and the U.S. Food and Drug Administration-Bacteriological Analytical Manual reference method, as measured by the Mantel-Haenszel Chi-square test. Ruggedness studies demonstrated little variation in test results when SIB incubation temperatures were varied over a 34-40 degrees C range. Lot-to-lot consistency results suggest no detectable differences in manufactured goods using two reference Salmonella serovars and one non-Salmonella microorganism.

Dual Regulation of the Small RNA MicC and the Quiescent Porin OmpN in Response to Antibiotic Stress in Escherichia coli

PubMed Central

Dam, Sushovan; Pagès, Jean-Marie

2017-01-01

Antibiotic resistant Gram-negative bacteria are a serious threat for public health. The permeation of antibiotics through their outer membrane is largely dependent on porin, changes in which cause reduced drug uptake and efficacy. Escherichia coli produces two major porins, OmpF and OmpC. MicF and MicC are small non-coding RNAs (sRNAs) that modulate the expression of OmpF and OmpC, respectively. In this work, we investigated factors that lead to increased production of MicC. micC promoter region was fused to lacZ, and the reporter plasmid was transformed into E. coli MC4100 and derivative mutants. The response of micC–lacZ to antimicrobials was measured during growth over a 6 h time period. The data showed that the expression of micC was increased in the presence of β-lactam antibiotics and in an rpoE depleted mutant. Interestingly, the same conditions enhanced the activity of an ompN–lacZ fusion, suggesting a dual transcriptional regulation of micC and the quiescent adjacent ompN. Increased levels of OmpN in the presence of sub-inhibitory concentrations of chemicals could not be confirmed by Western blot analysis, except when analyzed in the absence of the sigma factor σE. We suggest that the MicC sRNA acts together with the σE envelope stress response pathway to control the OmpC/N levels in response to β-lactam antibiotics. PMID:29211019

Meta-analysis of chicken--salmonella infection experiments.

PubMed

Te Pas, Marinus F W; Hulsegge, Ina; Schokker, Dirkjan; Smits, Mari A; Fife, Mark; Zoorob, Rima; Endale, Marie-Laure; Rebel, Johanna M J

2012-04-24

Chicken meat and eggs can be a source of human zoonotic pathogens, especially Salmonella species. These food items contain a potential hazard for humans. Chickens lines differ in susceptibility for Salmonella and can harbor Salmonella pathogens without showing clinical signs of illness. Many investigations including genomic studies have examined the mechanisms how chickens react to infection. Apart from the innate immune response, many physiological mechanisms and pathways are reported to be involved in the chicken host response to Salmonella infection. The objective of this study was to perform a meta-analysis of diverse experiments to identify general and host specific mechanisms to the Salmonella challenge. Diverse chicken lines differing in susceptibility to Salmonella infection were challenged with different Salmonella serovars at several time points. Various tissues were sampled at different time points post-infection, and resulting host transcriptional differences investigated using different microarray platforms. The meta-analysis was performed with the R-package metaMA to create lists of differentially regulated genes. These gene lists showed many similarities for different chicken breeds and tissues, and also for different Salmonella serovars measured at different times post infection. Functional biological analysis of these differentially expressed gene lists revealed several common mechanisms for the chicken host response to Salmonella infection. The meta-analysis-specific genes (i.e. genes found differentially expressed only in the meta-analysis) confirmed and expanded the biological functional mechanisms. The meta-analysis combination of heterogeneous expression profiling data provided useful insights into the common metabolic pathways and functions of different chicken lines infected with different Salmonella serovars.

78 FR 42526 - Salmonella

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-16

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2013-D-0254] Salmonella Contamination of Dry Dog Food; Withdrawal of Compliance Policy Guide AGENCY: Food and Drug... entitled ``Sec. 690.700 Salmonella Contamination of Dry Dog Food (CPG 690.700)'' on October 1, 1980. CPG...

Autophagy Facilitates Salmonella Replication in HeLa Cells

PubMed Central

Yu, Hong B.; Croxen, Matthew A.; Marchiando, Amanda M.; Ferreira, Rosana B. R.; Cadwell, Ken; Foster, Leonard J.; Finlay, B. Brett

2014-01-01

ABSTRACT Autophagy is a process whereby a double-membrane structure (autophagosome) engulfs unnecessary cytosolic proteins, organelles, and invading pathogens and delivers them to the lysosome for degradation. We examined the fate of cytosolic Salmonella targeted by autophagy and found that autophagy-targeted Salmonella present in the cytosol of HeLa cells correlates with intracellular bacterial replication. Real-time analyses revealed that a subset of cytosolic Salmonella extensively associates with autophagy components p62 and/or LC3 and replicates quickly, whereas intravacuolar Salmonella shows no or very limited association with p62 or LC3 and replicates much more slowly. Replication of cytosolic Salmonella in HeLa cells is significantly decreased when autophagy components are depleted. Eventually, hyperreplication of cytosolic Salmonella potentiates cell detachment, facilitating the dissemination of Salmonella to neighboring cells. We propose that Salmonella benefits from autophagy for its cytosolic replication in HeLa cells. PMID:24618251

In vitro studies of chicken egg yolk antibody (IgY) against Salmonella enteritidis and Salmonella typhimurium.

PubMed

Lee, E N; Sunwoo, H H; Menninen, K; Sim, J S

2002-05-01

Chicken egg yolk antibody (IgY) raised against Salmonella enteritidis or Salmonella typhimurium was found in highly specific activity levels by ELISA. S. enteritidis- and S. typhimurium-specific IgY powder, prepared by freeze-drying the egg yolk water-soluble fraction, contained 15.5 and 10.0% of specific IgY, respectively. Anti-S. enteritidis IgY cross-reacted 55.3% with S. typhimurium. The cross-reactivity of anti-S. typhimurium IgY with S. enteritidis was 42.4%. Salmonella-specific IgY was demonstrated to inhibit Salmonella growth in liquid medium. The growth rate of S. enteritidis incubated with S. enteritidis-specific IgY was fourfold less than that of the control group during a 4-to-6-h incubation. Cell counts of S. typhimurium incubated with S. typhimurium-specific IgY were reduced by 1.6 log cfu/mL in comparison to that of the control group after 6 h of incubation. The specific binding activity of IgY was further evaluated by using immunofluorescence and immunoelectron microscopy. It was found that Salmonella-specific IgY could bind to the antigens expressed on the Salmonella surface, resulting in structural alterations of the bacterial surface.

Regulation of Serratia marcescens ompF and ompC porin genes in response to osmotic stress, salicylate, temperature and pH.

PubMed

Begic, Sanela; Worobec, Elizabeth A

2006-02-01

Serratia marcescens is a Gram-negative enterobacterium that has become an important opportunistic pathogen, largely due to its high degree of natural antibiotic resistance. One factor contributing to this natural antibiotic resistance is reduced outer membrane permeability, which is controlled in part by OmpC and OmpF porin proteins. OmpF expression is regulated by micF, an RNA transcript encoded upstream of the ompC gene, which hybridizes with the ompF transcript to inhibit its translation. Regulation of S. marcescens porin gene expression, as well as that of micF, was investigated using beta-galactosidase reporter gene fusions in response to 5, 8 and 10 % sucrose, 1, 5 and 8 mM salicylate, and different pH and temperature values. beta-Galactosidase activity assays revealed that a lower growth temperature (28 degrees C), a more basic pH (pH 8), and an absence of sucrose and salicylate induce the transcription of the ompF gene, whereas the induction of ompC is stimulated at a higher growth temperature (42 degrees C), acidic pH (pH 6), and maximum concentrations of sucrose (10 %) and salicylate (8 mM). In addition, when multiple conditions were tested, temperature had the predominant effect, followed by pH. In this study, it was found that the MicF regulatory mechanism does not play a role in the osmoregulation of the ompF and ompC genes, whereas MicF does repress OmpF expression in the presence of salicylate and high growth temperature, and under low pH conditions.

Effects of Climate Change on Salmonella Infections

PubMed Central

Akil, Luma; Reddy, Remata S.

2014-01-01

Abstract Background: Climate change and global warming have been reported to increase spread of foodborne pathogens. To understand these effects on Salmonella infections, modeling approaches such as regression analysis and neural network (NN) were used. Methods: Monthly data for Salmonella outbreaks in Mississippi (MS), Tennessee (TN), and Alabama (AL) were analyzed from 2002 to 2011 using analysis of variance and time series analysis. Meteorological data were collected and the correlation with salmonellosis was examined using regression analysis and NN. Results: A seasonal trend in Salmonella infections was observed (p<0.001). Strong positive correlation was found between high temperature and Salmonella infections in MS and for the combined states (MS, TN, AL) models (R2=0.554; R2=0.415, respectively). NN models showed a strong effect of rise in temperature on the Salmonella outbreaks. In this study, an increase of 1°F was shown to result in four cases increase of Salmonella in MS. However, no correlation between monthly average precipitation rate and Salmonella infections was observed. Conclusion: There is consistent evidence that gastrointestinal infection with bacterial pathogens is positively correlated with ambient temperature, as warmer temperatures enable more rapid replication. Warming trends in the United States and specifically in the southern states may increase rates of Salmonella infections. PMID:25496072

Effects of climate change on Salmonella infections.

PubMed

Akil, Luma; Ahmad, H Anwar; Reddy, Remata S

2014-12-01

Climate change and global warming have been reported to increase spread of foodborne pathogens. To understand these effects on Salmonella infections, modeling approaches such as regression analysis and neural network (NN) were used. Monthly data for Salmonella outbreaks in Mississippi (MS), Tennessee (TN), and Alabama (AL) were analyzed from 2002 to 2011 using analysis of variance and time series analysis. Meteorological data were collected and the correlation with salmonellosis was examined using regression analysis and NN. A seasonal trend in Salmonella infections was observed (p<0.001). Strong positive correlation was found between high temperature and Salmonella infections in MS and for the combined states (MS, TN, AL) models (R(2)=0.554; R(2)=0.415, respectively). NN models showed a strong effect of rise in temperature on the Salmonella outbreaks. In this study, an increase of 1°F was shown to result in four cases increase of Salmonella in MS. However, no correlation between monthly average precipitation rate and Salmonella infections was observed. There is consistent evidence that gastrointestinal infection with bacterial pathogens is positively correlated with ambient temperature, as warmer temperatures enable more rapid replication. Warming trends in the United States and specifically in the southern states may increase rates of Salmonella infections.

Surveillance for human Salmonella infections in the United States.

PubMed

Swaminathan, Bala; Barrett, Timothy J; Fields, Patricia

2006-01-01

Surveillance for human Salmonella infections plays a critical role in understanding and controlling foodborne illness due to Salmonella. Along with its public health partners, the Centers for Disease Control and Prevention (CDC) has several surveillance systems that collect information on Salmonella infections in the United States. The National Salmonella Surveillance System, begun in 1962, receives reports of laboratory-confirmed Salmonella infections through state public health laboratories. Salmonella outbreaks are reported by state and local health departments through the Foodborne Disease Outbreak Reporting System, which became a Web-based, electronic system (eFORS) in 2001. PulseNet facilitates the detection of clusters of Salmonella infections through standardized molecular subtyping (DNA "fingerprinting") of isolates and maintenance of "fingerprint" databases. The National Antimicrobial Resistance Monitoring System for Enteric Bacteria (NARMS) monitors antimicrobial resistance in Salmonella by susceptibility testing of every 20th Salmonella isolate received by state and local public health laboratories. FootNet is an active surveillance system that monitors Salmonella infections in sentinel areas, providing population-based estimates of infection rates. Efforts are underway to electronically link all of the Salmonella surveillance systems at CDC to facilitate optimum use of available data and minimize duplication.

Testing Feeds for Salmonella.

USDA-ARS?s Scientific Manuscript database

Human salmonellosis outbreaks have been linked to contamination of animal feeds. Thus it is crucial to employ sensitive Salmonella detection methods for animal feeds. Based on a review of the literature, Salmonella sustains acid injury at about pH 4.0 to5.0. Low pH can also alter the metabolism of S...

Salmonella-secreted Virulence Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heffron, Fred; Niemann, George; Yoon, Hyunjin

In this short review we discuss secreted virulence factors of Salmonella, which directly affect Salmonella interaction with its host. Salmonella secretes protein to subvert host defenses but also, as discussed, to reduce virulence thereby permitting the bacteria to persist longer and more successfully disperse. The type III secretion system (TTSS) is the best known and well studied of the mechanisms that enable secretion from the bacterial cytoplasm to the host cell cytoplasm. Other secretion systems include outer membrane vesicles, which are present in all Gram-negative bacteria examined to date, two-partner secretion, and type VI secretion will also be addressed. Excellentmore » reviews of Salmonella secreted effectors have focused on themes such as actin rearrangements, vesicular trafficking, ubiquitination, and the activities of the virulence factors themselves. This short review is based on S. Typhimurium infection of mice because it is a model of typhoid like disease in humans. We have organized effectors in terms of events that happen during the infection cycle and how secreted effectors may be involved.« less

Characterization of nanostructured surfaces generated by reconstitution of the porin MspA from Mycobacterium smegmatis.

PubMed

Wörner, Michael; Lioubashevski, Oleg; Basel, Matthew T; Niebler, Sandra; Gogritchiani, Eliso; Egner, Nicole; Heinz, Christian; Hoferer, Jürgen; Cipolloni, Michela; Janik, Katharine; Katz, Evgeny; Braun, Andre M; Willner, Itamar; Niederweis, Michael; Bossmann, Stefan H

2007-06-01

Nanostructures with long-term stability at the surface of gold electrodes are generated by reconstituting the porin MspA from Mycobacterium smegmatis into a specially designed monolayer of long-chain lipid surfactant on gold. Tailored surface coverage of gold electrodes with long-chain surfactants is achieved by electrochemically assisted deposition of organic thiosulfates (Bunte salts). The subsequent reconstitution of the octameric-pore MspA is guided by its extraordinary self-assembling properties. Importantly, electrochemical reduction of copper(II) yields copper nanoparticles within the MspA nanopores. Electrochemical impedance spectroscopy, reflection electron microscopy, and atomic force microscopy (AFM) show that: 1) the MspA pores within the self-assembled monolayer (SAM) are monodisperse and electrochemically active, 2) MspA reconstitutes in SAMs and with a 10-nm thickness, 3) AFM is a suitable method to detect pores within SAMs, and 4) the electrochemical reduction of Cu2+ to Cu0 under overpotential conditions starts within the MspA pores.

Large-scale purification and biochemical characterization of crystallization-grade porin protein P from Pseudomonas aeruginosa.

PubMed

Worobec, E A; Martin, N L; McCubbin, W D; Kay, C M; Brayer, G D; Hancock, R E

1988-04-07

A large-scale purification scheme was developed for lipopolysaccharide-free protein P, the phosphate-starvation-inducible outer-membrane porin from Pseudomonas aeruginosa. This highly purified protein P was used to successfully form hexagonal crystals in the presence of n-octyl-beta-glucopyranoside. Amino-acid analysis indicated that protein P had a similar composition to other bacterial outer membrane proteins, containing a high percentage (50%) of hydrophilic residues. The amino-terminal sequence of this protein, although not homologous to either outer membrane protein, PhoE or OmpF, of Escherichia coli, was found to have an analogous protein-folding pattern. Protein P in the native trimer form was capable of maintaining a stable functional trimer after proteinase cleavage. This suggested the existence of a strongly associated tertiary and quaternary structure. Circular dichroism studies confirmed these results in that a large proportion of the protein structure was determined to be beta-sheet and resistant to acid pH and heating in 0.1% sodium dodecyl sulphate.

Assessment of Salmonella survival in dry-cured Italian salami.

PubMed

Bonardi, S; Bruini, I; Bolzoni, L; Cozzolino, P; Pierantoni, M; Brindani, F; Bellotti, P; Renzi, M; Pongolini, S

2017-12-04

The inactivation of Salmonella during curing of Italian traditional pork salami was investigated. A total of 150 batches of ground raw meat (GRM) used for salami manufacturing by four producers were tested for Salmonella by real-time PCR followed by ISO 6579 cultural confirmation and MPN enumeration. Salami produced with Salmonella positive GRMs were re-tested at the end of their curing period. Aw, pH and NaCl content were also measured. Detection of Salmonella was performed testing both 25 and 50g of the samples. By Real-Time PCR 37% of the GRMs resulted positive, but cultural detection of Salmonella was obtained in 14% of the samples only. Salmonella enumeration ranged from 31 MPN/g to <1.3 MPN/g. The difference between testing 50g and 25g of the samples was statistically significant (p value≤0.01). In particular, ISO-50g detected Salmonella in 100% of all positive samples, vs. 62% of ISO-25g. Salami made of the contaminated GRMs were 29% Salmonella-positive, as most batches of salami produced with Salmonella-positive GRMs resulted negative after regular curing (20-48days). Overall, 13% of salami produced with Salmonella-contaminated GRMs were positive. They belonged to six batches, which turned out negative after prolonged curing ranging between 49 and 86days. Salmonella enumeration in salami ranged from 8.7 MPN/g to <1.3 MPN/g. Unlike GRMs, no significant difference was observed between the ISO-50g and the ISO-25g in detecting Salmonella in cured salami (p value: >0.05). The most common Salmonella serovars in GRMs were Derby (52%), Typhimurium monophasic variant 4, (Barbuti et al., 1993), 12:i:- (19%) and Stanley (10%). Salmonella Derby (56%), London, Branderup, Panama (13%, respectively) and Goldcoast (6%) were most frequent in cured salami. The study showed negative correlation between real-time CT values and cultural confirmation of Salmonella, as well as the importance of sample size for Salmonella detection. Among considered factors with possible effect

Comparison of CHROMagar Salmonella Medium and Hektoen Enteric Agar for Isolation of Salmonellae from Stool Samples

PubMed Central

Gaillot, Olivier; Di Camillo, Patrick; Berche, Patrick; Courcol, René; Savage, Colette

1999-01-01

CHROMagar Salmonella (CAS), a new chromogenic medium, was retrospectively compared to Hektoen enteric agar (HEA) with 501 Salmonella stock isolates and was then prospectively compared to HEA for the detection and presumptive identification of Salmonella spp. with 508 stool samples before and after enrichment. All stock cultures (100%), including cultures of H2S-negative isolates, yielded typical mauve colonies on CAS, while 497 (99%) isolates produced typical lactose-negative, black-centered colonies on HEA. Following overnight incubation at 37°C, a total of 20 Salmonella strains were isolated from the 508 clinical samples. Sensitivities for primary plating and after enrichment were 95% (19 isolates) and 100% (20 isolates), respectively, for CAS and 80% (16 isolates) and 100% (20 isolates), respectively, for HEA. The specificity of CAS (88.9%) was significantly higher than that of HEA (78.5%; P < 0.0001). On the basis of its good sensitivity and specificity, CAS medium can be recommended for use for primary plating when human stool samples are screened for Salmonella spp. PMID:9986847

A single-tube screen for Salmonella and Shigella.

PubMed

Procop, Gary W; Wallace, Jacqueline D; Tuohy, Marion J; Lasalvia, Margret M; Addison, Rachel M; Reller, L Barth

2008-08-01

Salmonella and Shigella species are routinely sought in stool specimens submitted for culture. It is a common practice to screen lactose-negative colonies by using triple sugar iron agar, lysine iron agar, and Christensen urea agar to determine if further identification is necessary. We designed and evaluated a novel combination of media, which are layered in a single tube, for screening isolates suspected to possibly represent Salmonella or Shigella. We tested this media combination with 106 Salmonella, 56 Shigella, and 56 other gram-negative bacilli. All Salmonella and Shigella isolates tested were appropriately characterized as possible Salmonella or Shigella by using an algorithm developed for use with this media combination. Similarly, 53 (95%) of 56 other gram-negative bacilli were appropriately screened as non -Salmonella and non -Shigella isolates. This unique media combination provides the most important biochemical reactions needed to screen for Salmonella and Shigella in a single-tube format, which decreases labor by two thirds (ie, 1 tube is inoculated vs 3).

Meta-analysis of Chicken – Salmonella infection experiments

PubMed Central

2012-01-01

Background Chicken meat and eggs can be a source of human zoonotic pathogens, especially Salmonella species. These food items contain a potential hazard for humans. Chickens lines differ in susceptibility for Salmonella and can harbor Salmonella pathogens without showing clinical signs of illness. Many investigations including genomic studies have examined the mechanisms how chickens react to infection. Apart from the innate immune response, many physiological mechanisms and pathways are reported to be involved in the chicken host response to Salmonella infection. The objective of this study was to perform a meta-analysis of diverse experiments to identify general and host specific mechanisms to the Salmonella challenge. Results Diverse chicken lines differing in susceptibility to Salmonella infection were challenged with different Salmonella serovars at several time points. Various tissues were sampled at different time points post-infection, and resulting host transcriptional differences investigated using different microarray platforms. The meta-analysis was performed with the R-package metaMA to create lists of differentially regulated genes. These gene lists showed many similarities for different chicken breeds and tissues, and also for different Salmonella serovars measured at different times post infection. Functional biological analysis of these differentially expressed gene lists revealed several common mechanisms for the chicken host response to Salmonella infection. The meta-analysis-specific genes (i.e. genes found differentially expressed only in the meta-analysis) confirmed and expanded the biological functional mechanisms. Conclusions The meta-analysis combination of heterogeneous expression profiling data provided useful insights into the common metabolic pathways and functions of different chicken lines infected with different Salmonella serovars. PMID:22531008

Salmonella: an ecological success story

USDA-ARS?s Scientific Manuscript database

Salmonella was first described in 1885 as a secondary pathogen in the infectious disease process. In 1929, a paper published in the Proceedings of the Royal Society of Medicine reported that Salmonella organisms were predominant in food borne outbreaks but acknowledged that the path of infection wa...

Development of multiplex PCR assay for simultaneous detection of Salmonella genus, Salmonella subspecies I, Salm. Enteritidis, Salm. Heidelberg and Salm. Typhimurium.

PubMed

Park, S H; Ricke, S C

2015-01-01

The aim of this research was to develop multiplex PCR assay that could simultaneously detect Salmonella genus, Salmonella subsp. I, Salm. Enteritidis, Heidelberg and Typhimurium because these Salmonella serovars are the most common isolates associated with poultry products. Five primers were utilized to establish multiplex PCR and applied to Salmonella isolates from chickens and farm environments. These isolates were identified as Salmonella subsp. I and 16 of 66 isolates were classified as Salm. Enteritidis, while Heidelberg or Typhimurium was not detected. We also spiked three Salmonella strains on chicken breast meat to evaluate the specificity and sensitivity of multiplex PCR as well as qPCR to optimize quantification of Salmonella in these samples. The optimized multiplex PCR and qPCR could detect approx. 2·2 CFU of Salmonella per gram after 18 h enrichment. The multiplex PCR and qPCR would provide rapid and consistent results. Also, these techniques would be useful for the detection and quantification of Salmonella in contaminated poultry, foods and environmental samples. The strategy for the rapid detection of Salmonella serovars in poultry is needed to further reduce the incidence of salmonellosis in humans. The optimized multiplex PCR will be useful to detect prevalent Salmonella serovars in poultry products. © 2014 The Society for Applied Microbiology.

Salmonella Levels Associated with Skin of Turkey Parts.

PubMed

Peng, Ye; Deng, Xiang Y; Harrison, Mark A; Alali, Walid Q

2016-05-01

Turkey skin is used as a source of fat in finished ground turkey products. Salmonella-contaminated skin may potentially disseminate this pathogen to ground turkey. The objective of this study was to determine and compare Salmonella levels (presence and numbers) associated with the skin of turkey parts (i.e., drumstick, thigh, and wing). Over a 10-month period, 20 turkey flocks expected to be highly contaminated with Salmonella based on boot-sock testing data of turkey houses were sampled. A total of 300 samples per type of turkey part were collected postchill and were tested for Salmonella using the most-probable-number (MPN) and enrichment methods. Overall, Salmonella was detected in 13.7, 19.7, and 25.0% of drumstick skin, thigh skin, and wing skin samples, respectively. Salmonella prevalence from wing skin was significantly higher (P < 0.05) than in drumstick skin, but the difference was not significant (P > 0.05) when compared with thigh skin. Salmonella was 2.4 times more likely to be present from thigh skin (odds ratio = 2.4; P < 0.05) when the pathogen was found from wing skin. Salmonella mean numbers from drumstick, thigh, and wing were 1.18, 1.29, and 1.45 log MPN per sample, respectively; these values were not significantly different (P > 0.05). Based on our findings, the high prevalence of Salmonella associated with the skin of turkey parts could be a potential source for ground turkey contamination.

Salmonella serotype distribution in the Dutch broiler supply chain.

PubMed

van Asselt, E D; Thissen, J T N M; van der Fels-Klerx, H J

2009-12-01

Salmonella serotype distribution can give insight in contamination routes and persistence along a production chain. Therefore, it is important to determine not only Salmonella prevalence but also to specify the serotypes involved at the different stages of the supply chain. For this purpose, data from a national monitoring program in the Netherlands were used to estimate the serotype distribution and to determine whether this distribution differs for the available sampling points in the broiler supply chain. Data covered the period from 2002 to 2005, all slaughterhouses (n = 22), and the following 6 sampling points: departure from hatchery, arrival at the farm, departure from the farm, arrival at the slaughterhouse, departure from the slaughterhouse, and end of processing. Furthermore, retail data for 2005 were used for comparison with slaughterhouse data. The following serotypes were followed throughout the chain: Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Paratyphi B var. Java (Salmonella Java), Salmonella Infantis, Salmonella Virchow, and Salmonella Mbandaka. Results showed that serotype distribution varied significantly throughout the supply chain (P < 0.05). Main differences were found at the farm and at the slaughterhouse (within one stage), and least differences were found between departure from one stage and arrival at the next stage. The most prominent result was the increase of Salmonella Java at farm level. This serotype remained the most prominent pathogen throughout the broiler supply chain up to the retail phase.

Sources of salmonellae in an uninfected commercially-processed broiler flock.

PubMed

Rigby, C E; Pettit, J R; Baker, M F; Bentley, A H; Salomons, M O; Lior, H

1980-07-01

Cultural monitoring was used to study the incidence and sources of salmonellae in a 4160 bird broiler flock during the growing period, transport and processing in a commercial plant. No salmonellae were isolated from any of 132 litter samples of 189 chickens cultured during the seven-week growing period, even though nest litter samples from four of the eight parent flocks yielded salmonellae and Salmonella worthington was isolated from the meat meal component of the grower ration. On arrival at the plant, 2/23 birds sampled carried S. infantis on their feathers, although intestinal cultures failed to yield salmonellae. Three of 18 processed carcasses samples yielded salmonellae (S. infantis, S. heidelberg, S. typhimurium var copenhagen). The most likely source of these salmonellae was the plastic transport crates, since 15/107 sampled before the birds were loaded yielded salmonellae (S. infantis, S. typhimurium). The crate washer at the plant did not reduce the incidence of Salmonella-contaminated crates, since 16/116 sampled after washing yielded salmonellae (S. infantis, S. typhimurium, S. heidelberg, S. schwarzengrund, S. albany).

Salmonella: A century old conundrum

USDA-ARS?s Scientific Manuscript database

In 1885 a new bacterial species, Salmonella cholerae suis which was thought to cause hog cholera. Interestingly, Salmonella cholerae suis was not the etiologic agent of hog cholera (which is caused by a virus), but it was observed to be a secondary pathogen in the infectious process. In 1929, a pa...

Survival of Salmonella during baking of peanut butter cookies.

PubMed

Lathrop, Amanda A; Taylor, Tiffany; Schnepf, James

2014-04-01

Peanuts and peanut-based products have been the source of recent Salmonella outbreaks worldwide. Because peanut butter is commonly used as an ingredient in baked goods, such as cookies, the potential risk of Salmonella remaining in these products after baking needs to be assessed. This research examines the potential hazard of Salmonella in peanut butter cookies when it is introduced via the peanut-derived ingredient. The survival of Salmonella during the baking of peanut butter cookies was determined. Commercial, creamy-style peanut butter was artificially inoculated with a five-strain Salmonella cocktail at a target concentration of 10(8) CFU/g. The inoculated peanut butter was then used to prepare peanut butter cookie dough following a standard recipe. Cookies were baked at 350 °F (177 °C) and were sampled after 10, 11, 12, 13, 14, and 15 min. Temperature profiles of the oven and cookies were monitored during baking. The water activity and pH of the inoculated and uninoculated peanut butter, raw dough, and baked cookies were measured. Immediately after baking, cookies were cooled, and the survival of Salmonella was determined by direct plating or enrichment. After baking cookies for 10 min, the minimum reduction of Salmonella observed was 4.8 log. In cookies baked for 13 and 14 min, Salmonella was only detectable by enrichment reflecting a Salmonella reduction in the range of 5.2 to 6.2 log. Cookies baked for 15 min had no detectable Salmonella. Results of this study showed that proper baking will reduce Salmonella in peanut butter cookies by 5 log or more.

Dysregulated humoral immunity to nontyphoidal Salmonella in HIV-infected African adults

PubMed Central

MacLennan, Calman A.; Gilchrist, James J.; Gordon, Melita A.; Cunningham, Adam F.; Cobbold, Mark; Goodall, Margaret; Kingsley, Robert A.; van Oosterhout, Joep J. G.; Msefula, Chisomo L.; Mandala, Wilson L.; Leyton, Denisse L.; Marshall, Jennifer L.; Gondwe, Esther N.; Bobat, Saeeda; López-Macías, Constantino; Doffinger, Rainer; Henderson, Ian R.; Zijlstra, Eduard E.; Dougan, Gordon; Drayson, Mark T.; MacLennan, Ian C. M.; Molyneux, Malcolm E.

2013-01-01

Nontyphoidal Salmonellae are a major cause of life-threatening bacteremia among HIV-infected individuals. Although cell-mediated immunity controls intracellular infection, antibody protects against Salmonella bacteremia. We report that high titer antibodies specific for Salmonella lipopolysaccharide (LPS) associate with absent Salmonella-killing in HIV-infected African adults. Killing was restored by genetically shortening LPS from target Salmonella, or removing LPS-specific antibodies from serum. Complement-mediated killing of Salmonella by healthy serum is shown to be induced specifically by antibodies against outer membrane proteins. This killing is lost when excess antibody against Salmonella LPS is added. Thus our study indicates impaired immunity against nontyphoidal Salmonella bacteremia in HIV infection results from excess inhibitory antibodies against Salmonella LPS, whilst serum killing of Salmonella is induced by antibodies against outer membrane proteins. PMID:20413503

Salmonella induces prominent gene expression in the rat colon

PubMed Central

Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Roosing, Susanne; Vink, Carolien; Katan, Martijn B; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg MJ

2007-01-01

Background Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection. Results Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFNγ and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes. Conclusion We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression

Salmonella induces prominent gene expression in the rat colon.

PubMed

Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Roosing, Susanne; Vink, Carolien; Katan, Martijn B; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg M J

2007-09-12

Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection. Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFN gamma and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes. We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression.

Isolation of Salmonella enterica serovar Enteritidis from houseflies (Musca domestica) found in rooms containing Salmonella serovar Enteritidis-challenged hens.

PubMed

Holt, Peter S; Geden, Christopher J; Moore, Randle W; Gast, Richard K

2007-10-01

Houseflies (Musca domestica) released into rooms containing hens challenged with Salmonella enterica serovar Enteritidis (Salmonella serovar Enteritidis) rapidly became contaminated with Salmonella serovar Enteritidis. Forty to 50% of the flies were contaminated at 48 h, and the percentage increased to 50 to 70% at 4 and 7 days postexposure and then decreased to 30% at day 15. Initial attempts at recovering surface organisms for culture using an aqueous rinse were largely unsuccessful, while cultures of internal contents readily recovered Salmonella serovar Enteritidis. However, when 0.5% detergent was incorporated into the rinse, high recovery levels of bacteria were observed from both external and internal culture regimens, indicating equal distribution of the organism on and in the fly and a tighter interaction of the organism with the host than previously thought. Salmonella serovar Enteritidis was isolated routinely from the fly gut, on rare occasions from the crop, and never from the salivary gland. Feeding contaminated flies to hens resulted in gut colonization of a third of the birds, but release of contaminated flies in a room containing previously unchallenged hens failed to result in colonization of any of the subject birds. These results indicate that flies exposed to an environment containing Salmonella serovar Enteritidis can become colonized with the organism and might serve as a source for transmission of Salmonella serovar Enteritidis within a flock situation.

Isolation of Salmonella enterica Serovar Enteritidis from Houseflies (Musca domestica) Found in Rooms Containing Salmonella Serovar Enteritidis-Challenged Hens▿

PubMed Central

Holt, Peter S.; Geden, Christopher J.; Moore, Randle W.; Gast, Richard K.

2007-01-01

Houseflies (Musca domestica) released into rooms containing hens challenged with Salmonella enterica serovar Enteritidis (Salmonella serovar Enteritidis) rapidly became contaminated with Salmonella serovar Enteritidis. Forty to 50% of the flies were contaminated at 48 h, and the percentage increased to 50 to 70% at 4 and 7 days postexposure and then decreased to 30% at day 15. Initial attempts at recovering surface organisms for culture using an aqueous rinse were largely unsuccessful, while cultures of internal contents readily recovered Salmonella serovar Enteritidis. However, when 0.5% detergent was incorporated into the rinse, high recovery levels of bacteria were observed from both external and internal culture regimens, indicating equal distribution of the organism on and in the fly and a tighter interaction of the organism with the host than previously thought. Salmonella serovar Enteritidis was isolated routinely from the fly gut, on rare occasions from the crop, and never from the salivary gland. Feeding contaminated flies to hens resulted in gut colonization of a third of the birds, but release of contaminated flies in a room containing previously unchallenged hens failed to result in colonization of any of the subject birds. These results indicate that flies exposed to an environment containing Salmonella serovar Enteritidis can become colonized with the organism and might serve as a source for transmission of Salmonella serovar Enteritidis within a flock situation. PMID:17675422

Salmonella

USDA-ARS?s Scientific Manuscript database

Salmonella are facultative anaerobic Gram-negative non-spore forming rods belonging to the family Enterobacteriaceae. Salmonellosis is a zoonotic and foodborne illness that is usually transmitted by the fecal-oral route estimated to be responsible for 1.4 million cases of human infections in 2009 in...

Thermal inactivation of Salmonella spp. in pork burger patties.

PubMed

Gurman, P M; Ross, T; Holds, G L; Jarrett, R G; Kiermeier, A

2016-02-16

Predictive models, to estimate the reduction in Escherichia coli O157:H7 concentration in beef burgers, have been developed to inform risk management decisions; no analogous model exists for Salmonella spp. in pork burgers. In this study, "Extra Lean" and "Regular" fat pork minces were inoculated with Salmonella spp. (Salmonella 4,[5],12,i:-, Salmonella Senftenberg and Salmonella Typhimurium) and formed into pork burger patties. Patties were cooked on an electric skillet (to imitate home cooking) to one of seven internal temperatures (46, 49, 52, 55, 58, 61, 64 °C) and Salmonella enumerated. A generalised linear logistic regression model was used to develop a predictive model for the Salmonella concentration based on the internal endpoint temperature. It was estimated that in pork mince with a fat content of 6.1%, Salmonella survival will be decreased by -0.2407log10 CFU/g for a 1 °C increase in internal endpoint temperature, with a 5-log10 reduction in Salmonella concentration estimated to occur when the geometric centre temperature reaches 63 °C. The fat content influenced the rate of Salmonella inactivation (P=0.043), with Salmonella survival increasing as fat content increased, though this effect became negligible as the temperature approached 62 °C. Fat content increased the time required for patties to achieve a specified internal temperature (P=0.0106 and 0.0309 for linear and quadratic terms respectively), indicating that reduced fat pork mince may reduce the risk of salmonellosis from consumption of pork burgers. Salmonella serovar did not significantly affect the model intercepts (P=0.86) or slopes (P=0.10) of the fitted logistic curve. This predictive model can be applied to estimate the reduction in Salmonella in pork burgers after cooking to a specific endpoint temperature and hence to assess food safety risk. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Subinhibitory concentrations of phloretin repress the virulence of Salmonella typhimurium and protect against Salmonella typhimurium infection.

PubMed

Shuai-Cheng, Wu; Ben-Dong, Fu; Xiu-Ling, Chu; Jian-Qing, Su; Yun-Xing, Fu; Zhen-Qiang, Cui; Dao-Xiu, Xu; Zong-Mei, Wu

2016-11-01

Phloretin, a natural component of many fruits, exhibits anti-virulence effects and provides a new alternative to counter bacterial infection. The aim of this study was to determine the effect of subinhibitory concentrations of phloretin on the virulence of Salmonella typhimurium. At concentrations where growth of Salmonella was not inhibited, phloretin significantly inhibited bacteria biofilm formation and motility. Subinhibitory concentrations of phloretin repressed eight genes involved in the Salmonella pathogenicity island 1 and 3 genes involved in flagella production. Furthermore, subinhibitory concentrations of phloretin inhibited the adhesion and invasion of Salmonella in IEC-6 cells and reduced the LDH levels of S. typhimurium-infected IEC-6 cells. Additionally, phloretin significantly decreased the cecum bacterial loads of the mice infected with live S. typhimurium containing subinhibitory concentrations of phloretin by gavage. These results suggested that subinhibitory concentrations of phloretin attenuate the virulence of S. typhimurium and protect against S. typhimurium infection.

Incidence of Salmonella contamination in broiler chickens in Saskatchewan.

PubMed

Bhargava, K K; O'Neil, J B; Prior, M G; Dunkelgod, K E

1983-01-01

The incidence of Salmonella contamination in ten Saskatchewan broiler flocks varying in size from 6 200 to 14 000 was investigated from February, 1977 to April, 1979. Prior to the initial chick placement, brooding equipment, feed, water and fresh litter samples were found to be free of Salmonellae. Samples obtained from the clean and disinfected processing plant equipment before the commencement of daily operation were negative except the isolation for Salmonella anatum from the fingers of the defeathering machine in flock 4. There was no evidence of Salmonella contamination in flocks 5, 6, 8 and 10. The incidence of Salmonella was lower when cloacal swabs were taken from day old chicks fasted for 48 hours than for the same groups of chicks when carcasses were blended in nutrient broth (flocks 7 and 9). The blending of such chicks appears to be a more critical test. The serotypes isolated from eviscerated birds were the same as those isolated from used litter samples. Salmonella saintpaul was isolated from a water sample at 53 days in flock 1 and the same serotype was recovered from the intestinal contents and skin of eviscerated birds. Salmonella typhimurium was recovered from the eviscerated birds and neck samples in flock 3. In flock 4, S. saintpaul and S. anatum were isolated from 13% of the eviscerated birds sampled. Salmonella thompson, Salmonella agona and Salmonella heidelberg were recovered from 61%, 5% and 1%, respectively, of the processed carcasses sampled in flock 7.

Incidence of Salmonella Contamination in Broiler Chickens in Saskatchewan

PubMed Central

Bhargava, K.K.; O'Neil, J.B.; Prior, M.G.; Dunkelgod, K.E.

1983-01-01

The incidence of Salmonella contamination in ten Saskatchewan broiler flocks varying in size from 6 200 to 14 000 was investigated from February, 1977 to April, 1979. Prior to the initial chick placement, brooding equipment, feed, water and fresh litter samples were found to be free of Salmonellae. Samples obtained from the clean and disinfected processing plant equipment before the commencement of daily operation were negative except the isolation for Salmonella anatum from the fingers of the defeathering machine in flock 4. There was no evidence of Salmonella contamination in flocks 5, 6, 8 and 10. The incidence of Salmonella was lower when cloacal swabs were taken from day old chicks fasted for 48 hours than for the same groups of chicks when carcasses were blended in nutrient broth (flocks 7 and 9). The blending of such chicks appears to be a more critical test. The serotypes isolated from eviscerated birds were the same as those isolated from used litter samples. Salmonella saintpaul was isolated from a water sample at 53 days in flock 1 and the same serotype was recovered from the intestinal contents and skin of eviscerated birds. Salmonella typhimurium was recovered from the eviscerated birds and neck samples in flock 3. In flock 4, S. saintpaul and S. anatum were isolated from 13% of the eviscerated birds sampled. Salmonella thompson, Salmonella agona and Salmonella heidelberg were recovered from 61%, 5% and 1%, respectively, of the processed carcasses sampled in flock 7. PMID:6831304

Exchangeability of N termini in the ligand-gated porins of Escherichia coli.

PubMed

Scott, D C; Cao, Z; Qi, Z; Bauler, M; Igo, J D; Newton, S M; Klebba, P E

2001-04-20

The ferric siderophore transporters of the Gram-negative bacterial outer membrane manifest a unique architecture: Their N termini fold into a globular domain that lodges within, and physically obstructs, a transmembrane porin beta-barrel formed by their C termini. We exchanged and deleted the N termini of two such siderophore receptors, FepA and FhuA, which recognize and transport ferric enterobactin and ferrichrome, respectively. The resultant chimeric proteins and empty beta-barrels avidly bound appropriate ligands, including iron complexes, protein toxins, and viruses. Thus, the ability to recognize and discriminate these molecules fully originates in the transmembrane beta-barrel domain. Both the hybrid and the deletion proteins also transported the ferric siderophore that they bound. The FepA constructs showed less transport activity than wild type receptor protein, but the FhuA constructs functioned with turnover numbers that were equivalent to wild type. The mutant proteins displayed the full range of transport functionalities, despite their aberrant or missing N termini, confirming (Braun, M., Killmann, H., and Braun, V. (1999) Mol. Microbiol. 33, 1037-1049) that the globular domain within the pore is dispensable to the siderophore internalization reaction, and when present, acts without specificity during solute uptake. These and other data suggest a transport process in which siderophore receptors undergo multiple conformational states that ultimately expel the N terminus from the channel concomitant with solute internalization.

Applications of microscopy in Salmonella research.

PubMed

Malt, Layla M; Perrett, Charlotte A; Humphrey, Suzanne; Jepson, Mark A

2015-01-01

Salmonella enterica is a Gram-negative enteropathogen that can cause localized infections, typically resulting in gastroenteritis, or systemic infection, e.g., typhoid fever, in humans and many other animals. Understanding the mechanisms by which Salmonella induces disease has been the focus of intensive research. This has revealed that Salmonella invasion requires dynamic cross-talk between the microbe and host cells, in which bacterial adherence rapidly leads to a complex sequence of cellular responses initiated by proteins translocated into the host cell by a type 3 secretion system. Once these Salmonella-induced responses have resulted in bacterial invasion, proteins translocated by a second type 3 secretion system initiate further modulation of cellular activities to enable survival and replication of the invading pathogen. Elucidation of the complex and highly dynamic pathogen-host interactions ultimately requires analysis at the level of single cells and single infection events. To achieve this goal, researchers have applied a diverse range of microscopy techniques to analyze Salmonella infection in models ranging from whole animal to isolated cells and simple eukaryotic organisms. For example, electron microscopy and high-resolution light microscopy techniques such as confocal microscopy can reveal the precise location of Salmonella and its relationship to cellular components. Widefield light microscopy is a simpler approach with which to study the interaction of bacteria with host cells and often has advantages for live cell imaging, enabling detailed analysis of the dynamics of infection and cellular responses. Here we review the use of imaging techniques in Salmonella research and compare the capabilities of different classes of microscope to address specific types of research question. We also provide protocols and notes on some microscopy techniques used routinely in our own research.

Prevalence and antibiotic resistance of Salmonella Enteritidis and Salmonella Typhimurium in raw chicken meat at retail markets in Malaysia.

PubMed

Thung, T Y; Mahyudin, N A; Basri, D F; Wan Mohamed Radzi, C W J; Nakaguchi, Y; Nishibuchi, M; Radu, S

2016-08-01

Salmonellosis is one of the major food-borne diseases in many countries. This study was carried out to determine the occurrence of Salmonella spp., Salmonella Enteritidis, and Salmonella Typhimurium in raw chicken meat from wet markets and hypermarkets in Selangor, as well as to determine the antibiotic susceptibility profile of S. Enteritidis and S. Typhimurium. The most probable number (MPN) in combination with multiplex polymerase chain reaction (mPCR) method was used to quantify the Salmonella spp., S. Enteritidis, and S. Typhimurium in the samples. The occurrence of Salmonella spp., S. Enteritidis, and S. Typhimurium in 120 chicken meat samples were 20.80%, 6.70%, and 2.50%, respectively with estimated quantity varying from <3 to 15 MPN/g. The antibiogram testing revealed differential multi-drug resistance among S. Enteritidis and S. Typhimurium isolates. All the isolates were resistance to erythromycin, penicillin, and vancomycin whereas sensitivity was recorded for Amoxicillin/Clavulanic acid, Gentamicin, Tetracycline, and Trimethoprim. Our findings demonstrated that the retail chicken meat could be a source of multiple antimicrobial-resistance Salmonella and may constitute a public health concern in Malaysia. © 2016 Poultry Science Association Inc.

Isolation and characterization of Salmonella enterica in day-old ducklings in Egypt

PubMed Central

Osman, Kamelia M; Marouf, Sherif H; Zolnikov, Tara R; AlAtfeehy, Nayerah

2014-01-01

Importing day-old ducklings (DOD) unknowingly infected with non-typhoid Salmonella (NTS) may be associated with disease risk. Domestic and international trade may enhance this risk. Salmonella enterica serovars, their virulence genes combinations and antibiotic resistance, garner attention for their potentiality to contribute to the adverse health effects on populations throughout the world. The aim of this study was to estimate the risk of imported versus domestic DOD as potential carriers of NTS. The results confirm the prevalence of salmonellosis in imported ducklings was 18.5% (25/135), whereas only 12% (9/75) of cases were determined in the domestic ducklings. Fourteen serovars (Salmonella enteritidis, Salmonella kisii, Salmonella typhimurium, Salmonella gaillac, Salmonella uno, Salmonella eingedi, Salmonella shubra, Salmonella bardo, Salmonella inganda, Salmonella kentucky, Salmonella stanley, Salmonella virchow, Salmonella haifa, and Salmonella anatum) were isolated from the imported ducklings, whereas only S. enteritidis, S. typhimurium, S. virchow, and S. shubra were isolated from the domestic ducklings. The isolated Salmonella serovars were 100% susceptible to only colistin sulphate and 100% resistant to lincomycin. The 14 Salmonella serovars were screened for 11 virulence genes (invA, avrA, ssaQ, mgtC, siiD, sopB, gipA, sodC1, sopE1, spvC, and bcfC) by PCR. The invA, sopB, and bcfC genes were detected in 100% of the Salmonella serovars; alternatively, the gipA gene was absent in all of the isolated Salmonella serovars. The 11 virulent genes were not detected in either of S. stanley or S. haifa serovars. The results confirm an association between antibiotic resistance and virulence of Salmonella in the DOD. This study confirms the need for a country adherence to strict public health and food safety regimes. PMID:24548159

Reorganization of the Endosomal System in Salmonella-Infected Cells: The Ultrastructure of Salmonella-Induced Tubular Compartments

PubMed Central

Krieger, Viktoria; Liebl, David; Zhang, Yuying; Rajashekar, Roopa; Chlanda, Petr; Giesker, Katrin; Chikkaballi, Deepak; Hensel, Michael

2014-01-01

During the intracellular life of Salmonella enterica, a unique membrane-bound compartment termed Salmonella-containing vacuole, or SCV, is formed. By means of translocated effector proteins, intracellular Salmonella also induce the formation of extensive, highly dynamic membrane tubules termed Salmonella-induced filaments or SIF. Here we report the first detailed ultrastructural analyses of the SCV and SIF by electron microscopy (EM), EM tomography and live cell correlative light and electron microscopy (CLEM). We found that a subset of SIF is composed of double membranes that enclose portions of host cell cytosol and cytoskeletal filaments within its inner lumen. Despite some morphological similarities, we found that the formation of SIF double membranes is independent from autophagy and requires the function of the effector proteins SseF and SseG. The lumen of SIF network is accessible to various types of endocytosed material and our CLEM analysis of double membrane SIF demonstrated that fluid phase markers accumulate only between the inner and outer membrane of these structures, a space continual with endosomal lumen. Our work reveals how manipulation of the endosomal membrane system by an intracellular pathogen results in a unique tubular membrane compartmentalization of the host cell, generating a shielded niche permissive for intracellular proliferation of Salmonella. PMID:25254663

Salmonella spp. on chicken carcasses in processing plants in Poland.

PubMed

Mikołajczyk, Anita; Radkowski, Mieczysław

2002-09-01

Chickens at selected points in the slaughter process and after slaughter on the dressing line in poultry plants were sampled and analyzed for Salmonella. These chickens came from the northeast part of Poland. The examinations were carried out in quarters I, II, III, and IV of 1999. All the birds were determined to be healthy by a veterinary inspection. Swab samples were taken from the cloaca after stunning and from the skin surface and body cavity of the whole bird after evisceration, after rinsing at the final rinse station but before chilling in the spin-chiller, and after cooling in the continuous cooling plant at the end of the production day. In 1999, 400 whole chickens were examined. The percentage of these 400 chickens from which Salmonella spp. were isolated was relatively high (23.75%; Salmonella-positive results were observed in 95 cases). Salmonella spp. were found after stunning in 6% of the chickens (6 of 100 samples), after evisceration in 24% (24 of 100), before cooling in 52% (52 of 100), and after cooling in 13% (13 of 100). These results show that Salmonella spp. were found more often at some processing points than at others. The lowest Salmonella spp. contamination rate (6%) for slaughter birds was found after stunning, and the highest contamination rate was found before chilling (52%). The serological types of Salmonella spp. isolated from whole chickens were Salmonella Enteritidis, Salmonella Typhimurium, Salmonella Saintpaul, Salmonella Agona, and Salmonella Infantis. The results of these investigations indicate that Salmonella Enteritidis is the dominant serological type in infections of slaughter chickens, as it is in many countries.

9 CFR 113.30 - Detection of Salmonella contamination.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Detection of Salmonella contamination... REQUIREMENTS Standard Procedures § 113.30 Detection of Salmonella contamination. The test for detection of Salmonella contamination provided in this section shall be conducted when such a test is prescribed in an...

9 CFR 113.30 - Detection of Salmonella contamination.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Detection of Salmonella contamination... REQUIREMENTS Standard Procedures § 113.30 Detection of Salmonella contamination. The test for detection of Salmonella contamination provided in this section shall be conducted when such a test is prescribed in an...

Evaluation of 3M molecular detection assay (MDA) Salmonella for the detection of Salmonella in selected foods: collaborative study.

PubMed

Bird, Patrick; Fisher, Kiel; Boyle, Megan; Huffman, Travis; Benzinger, M Joseph; Bedinghaus, Paige; Flannery, Jonathan; Crowley, Erin; Agin, James; Goins, David; Benesh, DeAnn; David, John

2013-01-01

The 3M Molecular Detection Assay (MDA) Salmonella is used with the 3M Molecular Detection System for the detection of Salmonella spp. in food, food-related, and environmental samples after enrichment. The assay utilizes loop-mediated isothermal amplification to rapidly amplify Salmonella target DNA with high specificity and sensitivity, combined with bioluminescence to detect the amplification. The 3M MDA Salmonella method was compared using an unpaired study design in a multilaboratory collaborative study to the U.S. Department of Agriculture/Food Safety and Inspection Service-Microbiology Laboratory Guidebook (USDA/FSIS-MLG 4.05), Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg and Catfish Products for raw ground beef and the U.S. Food and Drug Administration/Bacteriological Analytical Manual (FDA/BAM) Chapter 5 Salmonella reference method for wet dog food following the current AOAC guidelines. A total of 20 laboratories participated. For the 3M MDA Salmonella method, raw ground beef was analyzed using 25 g test portions, and wet dog food was analyzed using 375 g test portions. For the reference methods, 25 g test portions of each matrix were analyzed. Each matrix was artificially contaminated with Salmonella at three inoculation levels: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). In this study, 1512 unpaired replicate samples were analyzed. Statistical analysis was conducted according to the probability of detection (POD). For the low-level raw ground beef test portions, the following dLPOD (difference between the POD of the reference and candidate method) values with 95% confidence intervals were obtained: -0.01 (-0.14, +0.12). For the low-level wet dog food test portions, the following dLPOD with 95% confidence intervals were obtained: -0.04 (-0.16, +0.09). No significant differences were observed in the number of positive

The major sources of Salmonella enteritidis in Thailand.

PubMed

Sakai, T; Chalermchaikit, T

1996-08-01

The data of Salmonella serotypes during 1989-1993 from the World Health Organisation (WHO) National Salmonella and Shigella Center, Division of Clinical Pathology, Department of Medical Science, Ministry of Health, Thailand was analysed and found that the prevalence of Salmonella enteritidis had been dramatically increased since 1990. The average S. enteritidis isolates from human patient samples was 0.70% +/- 0.41% of the total reported Salmonella isolates during 1972-1989 and increased to 1.33%, 2.98%, 9.54%, and 16.98% in 1990, 1991, 1992, and 1993, respectively. The similar trend of S. enteritidis isolates from chicken meat samples were also observed. However, the conclusive epidemiological relationship between human and chicken S. enteritidis isolates needs to be proved by phage typing or other Salmonella typing methods.

Comparison of Microbial Communities Isolated from Feces of Asymptomatic Salmonella-Shedding and Non-Salmonella Shedding Dairy Cows

PubMed Central

Haley, Bradd J.; Pettengill, James; Gorham, Sasha; Ottesen, Andrea; Karns, Jeffrey S.; Van Kessel, Jo Ann S.

2016-01-01

In the United States Salmonella enterica subsp. enterica serotypes Kentucky and Cerro are frequently isolated from asymptomatic dairy cows. However, factors that contribute to colonization of the bovine gut by these two serotypes have not been identified. To investigate associations between Salmonella status and bacterial diversity, as well as the diversity of the microbial community in the dairy cow hindgut, the bacterial and archaeal communities of fecal samples from cows on a single dairy farm were determined by high-throughput sequencing of 16S rRNA gene amplicons. Fecal grab samples were collected from two Salmonella-positive cows and two Salmonella-negative cows on five sampling dates (n = 20 cows), and 16S rRNA gene amplicons from these samples were sequenced on the Illumina MiSeq platform. A high level of alpha (within) and beta diversity (between) samples demonstrated that microbial profiles of dairy cow hindguts are quite diverse. To determine whether Salmonella presence, sampling year, or sampling date explained a significant amount of the variation in microbial diversity, we performed constrained ordination analyses (distance based RDA) on the unifrac distance matrix produced with QIIME. Results indicated that there was not a significant difference in the microbial diversity associated with Salmonella presence (P > 0.05), but there were significant differences between sampling dates and years (Pseudo-F = 2.157 to 4.385, P < 0.05). Based on these data, it appears that commensal Salmonella infections with serotypes Cerro and Kentucky in dairy cows have little or no association with changes in the abundance of major bacterial groups in the hindgut. Rather, our results indicated that temporal dynamics and other undescribed parameters associated with them were the most influential drivers of the differences in microbial diversity and community structure in the dairy cow hindgut. PMID:27313565

Interactions of Salmonella with animals and plants.

PubMed

Wiedemann, Agnès; Virlogeux-Payant, Isabelle; Chaussé, Anne-Marie; Schikora, Adam; Velge, Philippe

2014-01-01

Salmonella enterica species are Gram-negative bacteria, which are responsible for a wide range of food- and water-borne diseases in both humans and animals, thereby posing a major threat to public health. Recently, there has been an increasing number of reports, linking Salmonella contaminated raw vegetables and fruits with food poisoning. Many studies have shown that an essential feature of the pathogenicity of Salmonella is its capacity to cross a number of barriers requiring invasion of a large variety of cells and that the extent of internalization may be influenced by numerous factors. However, it is poorly understood how Salmonella successfully infects hosts as diversified as animals or plants. The aim of this review is to describe the different stages required for Salmonella interaction with its hosts: (i) attachment to host surfaces; (ii) entry processes; (iii) multiplication; (iv) suppression of host defense mechanisms; and to point out similarities and differences between animal and plant infections.

Prevalence of Salmonella in diverse environmental farm samples.

PubMed

Rodriguez, Andres; Pangloli, Philipus; Richards, Harold A; Mount, John R; Draughon, F Ann

2006-11-01

The development of suitable intervention strategies to control Salmonella populations at the farm level requires reliable data on the occurrence and prevalence of the pathogen. Previous studies on Salmonella prevalence have focused on acquiring data from specific farm types and/or selected regions. The purpose of this study was to evaluate the distribution of this pathogen across a variety of farm types and regions in order to generate comparative data from a diverse group of environmental samples. Farm samples (n = 2,496) were collected quarterly from 18 different farms across five states (Tennessee, North Carolina, Alabama, California, and Washington) over a 24-month period. The participating farms included beef and dairy cattle operations, swine production and farrowing facilities, and poultry farms (both broiler chicken and turkey). The samples were analyzed for the presence of Salmonella by means of the U.S. Food and Drug Administration's Bacteriological Analytical Manual methods optimized for farm samples. Salmonella isolates were characterized by automated riboprinting. Salmonella serovars were recovered from 4.7% of all samples. The majority of positive findings were isolated from swine farms (57.3%). The occurrence of Salmonella was lower on dairy farms (17.9%), poultry farms (16.2%), and beef cattle farms (8.5%). The most commonly isolated serovar was Salmonella Anatum (48.4%), which was isolated notably more frequently than the next most common Salmonella serovars, Arizonae (12.1%) and Javiana (8.8%). The results of this study suggest that significant reservoirs of Salmonella populations still exist on swine production facilities and to a lesser extent in other animal production facilities. Data showed that the surrounding farm environment could be an important source of contamination.

Salmonella in beef and produce from honduras.

PubMed

Maradiaga, Martha; Miller, Mark F; Thompson, Leslie; Pond, Ansen; Gragg, Sara E; Echeverry, Alejandro; Garcia, Lyda G; Loneragan, Guy H; Brashears, Mindy M

2015-03-01

Salmonella continues to cause a considerable number of foodborne illnesses worldwide. The sources of outbreaks include contaminated meat and produce. The purpose of this study was to establish an initial investigation of the burden of Salmonella in produce and beef from Honduras by sampling retail markets and abattoirs. Retail produce samples (cantaloupes, cilantro, cucumbers, leafy greens, peppers, and tomatoes; n = 573) were purchased in three major cities of Honduras, and retail whole-muscle beef (n = 555) samples were also purchased in four major cities. Additionally, both hide and beef carcass (n = 141) samples were collected from two Honduran abattoirs. Whole-muscle beef samples were obtained using a sponge hydrated with buffered peptone water, and 10 ml of the buffered peptone water rinsate of each produce sample was collected with a dry sponge and placed in a bag to be transported back to the United States. Salmonella was detected using a commercially available, closeplatform PCR system, and positive samples were subjected to culture on selective media to obtain isolates. Overall, the prevalence of Salmonella-positive samples, based on PCR detection in Honduras (n = 555) retail beef was 10.1% (95% confidence interval = 7.8, 12.9), whereas 7.8% (n = 141) of beef carcass and hides samples were positive in both beef plants. The overall Salmonella prevalence for all produce samples (n = 573) collected was 2.1% (95% confidence interval = 1.2, 3.6). The most common serotypes identified in Honduras were Salmonella Typhimurium followed by Derby. These results provide an indication of Salmonella contamination of beef and produce in Honduras. Developing a Salmonella baseline for Latin America through an initial investigation like the one presented here contributes to a broader global understanding of the potential exposure through food, thus providing insight into the needs for control strategies.

Immunity to Intracellular Salmonella Depends on Surface-associated Antigens

PubMed Central

Claudi, Beatrice; Mazé, Alain; Schemmer, Anne K.; Kirchhoff, Dennis; Schmidt, Alexander; Burton, Neil; Bumann, Dirk

2012-01-01

Invasive Salmonella infection is an important health problem that is worsening because of rising antimicrobial resistance and changing Salmonella serovar spectrum. Novel vaccines with broad serovar coverage are needed, but suitable protective antigens remain largely unknown. Here, we tested 37 broadly conserved Salmonella antigens in a mouse typhoid fever model, and identified antigen candidates that conferred partial protection against lethal disease. Antigen properties such as high in vivo abundance or immunodominance in convalescent individuals were not required for protectivity, but all promising antigen candidates were associated with the Salmonella surface. Surprisingly, this was not due to superior immunogenicity of surface antigens compared to internal antigens as had been suggested by previous studies and novel findings for CD4 T cell responses to model antigens. Confocal microscopy of infected tissues revealed that many live Salmonella resided alone in infected host macrophages with no damaged Salmonella releasing internal antigens in their vicinity. In the absence of accessible internal antigens, detection of these infected cells might require CD4 T cell recognition of Salmonella surface-associated antigens that could be processed and presented even from intact Salmonella. In conclusion, our findings might pave the way for development of an efficacious Salmonella vaccine with broad serovar coverage, and suggest a similar crucial role of surface antigens for immunity to both extracellular and intracellular pathogens. PMID:23093937

Salmonella prevalence in bovine lymph nodes differs among feedyards.

PubMed

Haneklaus, Ashley N; Harris, Kerri B; Griffin, Davey B; Edrington, Thomas S; Lucia, Lisa M; Savell, Jeffrey W

2012-06-01

Lymphatic tissue, specifically lymph nodes, is commonly incorporated into ground beef products as a component of lean trimmings. Salmonella and other pathogenic bacteria have been identified in bovine lymph nodes, which may impact compliance with the Salmonella performance standards for ground beef established by the U.S. Department of Agriculture. Although Salmonella prevalence has been examined among lymph nodes between animals, no data are currently available regarding feedyard origin of the cattle and Salmonella prevalence. Bovine lymph nodes (279 superficial cervical plus 28 iliofemoral = 307) were collected from beef carcasses at a commercial beef harvest and processing plant over a 3-month period and examined for the prevalence of Salmonella. Cattle processed were from seven feedyards (A through G). Salmonella prevalence was exceptionally low (0% of samples were positive ) in cattle from feedyard A and high (88.2%) in cattle from feedyard B. Prevalence in the remaining feedyards ranged widely: 40.0% in feedyard C, 4.0% in feedyard D, 24.0% in feedyard E, 42.9% in feedyard F, and 40.0% in feedyard G. These data indicate the range of differences in Salmonella prevalence among feedyards. Such information may be useful for developing interventions to reduce or eliminate Salmonella from bovine lymph nodes, which would assist in the reduction of Salmonella in ground beef.

Laboratory-based Salmonella surveillance in Fiji, 2004-2005.

PubMed

Dunn, John; Pryor, Jan; Saketa, Salanieta; Delai, Wasale; Buadromo, Eka; Kishore, Kamal; Naidu, Shakila; Greene, Sharon; Varma, Jay; Chiller, Tom

2005-09-01

Although foodborne diseases are an important public health problem worldwide, the burden of foodborne illness is not well described in most Pacific Island Countries and Territories. Laboratory-based surveillance programs can detect trends and outbreaks, estimate burden of illness, and allow subtyping of enteric pathogens (e.g. Salmonella serotyping), which is critical for linking illness to food vehicles and animal reservoirs. To enhance public health capacity in Fiji for foodborne disease surveillance, we developed the Salmonella Surveillance Project (SSP), a collaboration to pilot laboratory-based surveillance for Salmonella. A network of national and international partners was formed including epidemiologists, microbiologists, and environmental health personnel. Ministry of Health personnel were trained in foodborne disease surveillance and outbreak investigation. Three clinical microbiology laboratories from different parts of the country functioned as sentinel sites, reporting all laboratory-confirmed Salmonella infections using a standardized case report form. Non-Typhi Salmonella isolates were collected for serotyping. In 2004-2005, 86 non-Typhi Salmonella and 275 S. Typhi laboratory-confirmed infections were reported. Salmonella enterica serotype I 3,10: r:- and Salmonella enterica serotype Weltevreden were the most commonly isolated non-Typhi serotypes. In Fiji, the SSP utilized international partnerships to facilitate training, and to enhance laboratory capacity and surveillance for salmonellosis. Incorporating laboratory-based foodborne disease reporting into national disease surveillance will enable public health officials to describe the burden of foodborne illness, identify outbreaks, conduct analytic epidemiology studies, and improve food safety.

Diversity of Salmonella isolates from central Florida surface waters.

PubMed

McEgan, Rachel; Chandler, Jeffrey C; Goodridge, Lawrence D; Danyluk, Michelle D

2014-11-01

Identification of Salmonella serotypes is important for understanding the environmental diversity of the genus Salmonella. This study evaluates the diversity of Salmonella isolates recovered from 165 of 202 Central Florida surface water samples and investigates whether the serotype of the environmental Salmonella isolates can be predicted by a previously published multiplex PCR assay (S. Kim, J. G. Frye, J. Hu, P. J. Fedorka-Cray, R. Gautom, and D. S. Boyle, J. Clin. Microbiol. 44:3608-3615, 2006, http://dx.doi.org/10.1128/JCM.00701-06). Multiplex PCR was performed on 562 Salmonella isolates (as many as 36 isolates per water sample) to predict serotypes. Kauffmann-White serogrouping was used to confirm multiplex PCR pattern groupings before isolates were serotyped, analyzed by pulsed-field gel electrophoresis, and assayed for antimicrobial susceptibility. In 41.2% of the Salmonella-positive water samples, all Salmonella isolates had identical multiplex PCR patterns; in the remaining 58.8%, two or more multiplex PCR patterns were identified. Within each sample, isolates with matching multiplex PCR patterns had matching serogroups. The multiplex patterns of 495 isolates (88.1%) did not match any previously reported pattern. The remaining 68 isolates matched reported patterns but did not match the serotypes for those patterns. The use of the multiplex PCR allowed the number of isolates requiring further analysis to be reduced to 223. Thirty-three Salmonella enterica serotypes were identified; the most frequent included serotypes Muenchen, Rubislaw, Anatum, Gaminara, and IV_50:z4,z23:-. A majority (141/223) of Salmonella isolates clustered into one genotypic group. Salmonella isolates in Central Florida surface waters are serotypically, genotypically, and phenotypically (in terms of antimicrobial susceptibility) diverse. While isolates could be grouped as different or potentially the same using multiplex PCR, the multiplex PCR pattern did not predict the Salmonella

Diversity of Salmonella Isolates from Central Florida Surface Waters

PubMed Central

McEgan, Rachel; Chandler, Jeffrey C.; Goodridge, Lawrence D.

2014-01-01

Identification of Salmonella serotypes is important for understanding the environmental diversity of the genus Salmonella. This study evaluates the diversity of Salmonella isolates recovered from 165 of 202 Central Florida surface water samples and investigates whether the serotype of the environmental Salmonella isolates can be predicted by a previously published multiplex PCR assay (S. Kim, J. G. Frye, J. Hu, P. J. Fedorka-Cray, R. Gautom, and D. S. Boyle, J. Clin. Microbiol. 44:3608–3615, 2006, http://dx.doi.org/10.1128/JCM.00701-06). Multiplex PCR was performed on 562 Salmonella isolates (as many as 36 isolates per water sample) to predict serotypes. Kauffmann-White serogrouping was used to confirm multiplex PCR pattern groupings before isolates were serotyped, analyzed by pulsed-field gel electrophoresis, and assayed for antimicrobial susceptibility. In 41.2% of the Salmonella-positive water samples, all Salmonella isolates had identical multiplex PCR patterns; in the remaining 58.8%, two or more multiplex PCR patterns were identified. Within each sample, isolates with matching multiplex PCR patterns had matching serogroups. The multiplex patterns of 495 isolates (88.1%) did not match any previously reported pattern. The remaining 68 isolates matched reported patterns but did not match the serotypes for those patterns. The use of the multiplex PCR allowed the number of isolates requiring further analysis to be reduced to 223. Thirty-three Salmonella enterica serotypes were identified; the most frequent included serotypes Muenchen, Rubislaw, Anatum, Gaminara, and IV_50:z4,z23:−. A majority (141/223) of Salmonella isolates clustered into one genotypic group. Salmonella isolates in Central Florida surface waters are serotypically, genotypically, and phenotypically (in terms of antimicrobial susceptibility) diverse. While isolates could be grouped as different or potentially the same using multiplex PCR, the multiplex PCR pattern did not predict the Salmonella

Salmonella Overcomes Drug Resistance in Tumor through P-glycoprotein Downregulation.

PubMed

Yang, Chih-Jen; Chang, Wen-Wei; Lin, Song-Tao; Chen, Man-Chin; Lee, Che-Hsin

2018-01-01

Chemotherapy is one of effective methods for the treatment of tumor. Patients often develop drug resistance after chemotherapic cycles. Salmonella has potential as antitumor agent. Salmonella used in tandem with chemotherapy had additive effects, providing a rationale for using tumor-targeting Salmonella in combination with conventional chemotherapy. To improve the efficacy and safety of Salmonella , a further understanding of Salmonella interactions with the tumor microenvironment is required. The presence of plasma membrane multidrug resistance protein P-glycoprotein (P-gp) is highly relevant for the success of chemotherapy. Following Salmonella infection, dose-dependent downregulation of P-gp expressions were examined. Salmonella significantly decreased the efflux capabilities of P-gp, as based on the influx of Rhodamine 123 assay. In addition, Salmonella significant reduced the protein express the expression levels of phosph-protein kinase B (P-AKT), phosph-mammalian targets of rapamycin (P-mTOR), and phosph-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells. The Salmonella -induced downregulation of P-gp was rescued by transfection of cells with active P-AKT. Our results demonstrate that Salmonella in tumor sites leads to decrease the expression of P-gp and enhances the combination of Salmonell a and 5-Fluorouracil therapeutic effects.

Salmonella Infections

MedlinePlus

... reptiles like snakes, turtles, and lizards. Symptoms include Fever Diarrhea Abdominal cramps Headache Possible nausea, vomiting, and ... be serious. The usual treatment is antibiotics. Typhoid fever, a more serious disease caused by Salmonella, is ...

Salmonella Isolates in the Introduced Asian House Gecko (Hemidactylus frenatus) with Emphasis on Salmonella Weltevreden, in Two Regions in Costa Rica.

PubMed

Jiménez, Randall R; Barquero-Calvo, Elías; Abarca, Juan G; Porras, Laura P

2015-09-01

The Asian house gecko Hemidactylus frenatus has been widely introduced in Costa Rica and tends to establish in human settlements. Some studies in other invaded countries have suggested that this gecko plays a significant role in the epidemiology of salmonellosis and it is of value to public health. To our knowledge, no studies have examined Salmonella from this species in Costa Rica. Therefore, we collected 115 geckos from houses in two Costa Rican regions. We examined gut contents for Salmonella through microbiological analysis. Presumptive Salmonella spp. were sent to a reference laboratory for serotyping and antimicrobial susceptibility testing. Molecular typing was also conducted with the main Salmonella isolates of zoonotic relevance in Costa Rica. H. frenatus was found in 95% of the houses surveyed. Salmonella was isolated in 4.3% of the samples, and four zoonotic serovars were detected. None of the isolates were resistant to the antibiotics most frequently used for salmonellosis treatment in Costa Rica. All Salmonella isolates from the lower gut of H. frenatus are associated with human salmonellosis. Pulsotypes from Salmonella enterica serotype Weltevreden were identical to the only clone previously reported from human samples in Costa Rica. Molecular typing of Salmonella Weltevreden suggested that H. frenatus harbors a serovar of public health importance in Costa Rica. Results demonstrated that H. frenatus plays a role in the epidemiology of human salmonellosis in two regions of Costa Rica. However, more detailed epidemiological studies are needed to understand better the role of the Asian house gecko with human salmonellosis, especially caused by Salmonella Weltevreden, and to quantify its risk in Costa Rica accurately.

Prevalence of salmonella in neck skin and bone of chickens.

PubMed

Wu, Diezhang; Alali, W Q; Harrison, M A; Hofacre, C L

2014-07-01

Bone-in and boneless parts, such as drumsticks, are used in ground chicken production. In addition, neck skin is used as a source of fat in ground products. Contaminated chicken neck skin and bones containing internalized Salmonella are potential sources of this pathogen in ground chicken. This study determined the prevalence of Salmonella and serotype distribution in drumstick bones and neck skin of postchill chicken carcasses. One week prior to slaughter, chicken houses (n = 26) at nine farms were tested for the presence of Salmonella, using the boot sock method. Chicken flocks from these houses originated from Salmonella-positive breeders. Eight Salmonella-positive chicken flocks and one flock with undetermined Salmonella status were monitored through processing. Three hundred postchill drumsticks and 299 neck skin samples were analyzed for Salmonella prevalence. Skin samples were rinsed and stomached prior to analysis. Bones were extracted from the drumsticks, external surfaces were sterilized, and bones were crushed for analysis. One Salmonella isolate from each positive sample was serogrouped. Half of the isolates representing different sample types were serotyped. Overall, Salmonella was found in 0.8, 21.4, and 80.1% of bone marrow, neck skin, and farms, respectively. Prevalence of Salmonella on rinsed skin samples (2.3%) and stomached skin samples (20.7%) differed significantly (P ≤ 0.05). Serogroups B, C2, D, and E were found at 23.4, 31.9, 11.7, and 29.8%, respectively. Six Salmonella serotypes were identified: Liverpool (37.9%), Kentucky (27.6%), and Typhimurium (27.6%) were isolated most frequently from neck skin; the two bone isolates were Kentucky; and more than 50% of the farm isolates were Kentucky and Ouakam. Salmonella-contaminated neck skin might be a more significant source of this contamination in ground chicken than Salmonella internalized in bones.

Salmonella-based plague vaccines for bioterrorism.

PubMed

Calhoun, Leona Nicole; Kwon, Young-Min

2006-04-01

Yersinia pestis, the causative agent of plague, is an emerging threat as a means of bioterrorism. Accordingly, the Working Group on Civilian Biodefense, as well as the Centers for Disease Control and Prevention, has specified Y. pestis as a prime candidate for use in bioterrorism. As the threat of bioterrorism increases, so does the need for an effective vaccine against this potential agent. Experts agree that a stable, non-invasive vaccine would be necessary for the rapid large-scale immunization of a population following a bioterrorism attack. Thus far, live Salmonella-based oral vaccines show the most potential for this purpose. When delivered via a mucosal route, Salmonella-based plague vaccines show the ability to protect against the deadly pneumonic form of plague. Also, mass production, distribution, and administration are easier and less costly for attenuated Salmonella-based plague vaccines than for plague vaccines consisting of purified proteins. Most attenuated Salmonella-based plague vaccines have utilized a plasmid-based expression system to deliver plague antigen(s) to the mucosa. However, these systems are frequently associated with plasmid instability, an increased metabolic burden upon the vaccine strain, and highly undesirable antibiotic resistance genes. The future of Salmonella-based plague vaccines seems to lie in the use of chromosomally encoded plague antigens and the use of in vivo inducible promoters to drive their expression. This method of vaccine development has been proven to greatly increase the retention of foreign genes, and also eliminates the need for antibiotic resistance genes within Salmonella-based vaccines.

Transcriptomic analysis of Salmonella desiccation resistance.

PubMed

Li, Haiping; Bhaskara, Anuhya; Megalis, Christina; Tortorello, Mary Lou

2012-12-01

The survival of Salmonella in low moisture foods and processing environments remains a great challenge for the food industry and public health. To explore the mechanisms of Salmonella desiccation resistance, we studied the transcriptomic responses in Salmonella Tennessee (Tennessee), using Salmonella Typhimurium LT2 (LT2), a strain weakly resistant to desiccation, as a reference strain. In response to 2 h of air-drying at 11% equilibrated relative humidity, approximately one-fourth of the open reading frames (ORFs) in the Tennessee genome and one-fifth in LT2 were differentially expressed (>2-fold). Among all differentially expressed functional groups (>5-fold) in both strains, the expression fold change associated with fatty acid metabolism was the highest, and constituted 51% and 35% of the total expression fold change in Tennessee and LT2, respectively. Tennessee showed greater changes in expression of genes associated with stress response and envelope modification than LT2, while showing lesser changes in protein biosynthesis expression. Expression of flagella genes was significantly more inhibited in stationary phase cells of Tennessee than LT2 both before and after desiccation. The accumulation of the osmolyte trehalose was significantly induced by desiccation in Tennessee, but no increase was detectable in LT2, which is consistent with the expression patterns of the entire trehalose biosynthesis and degradation pathways in both strains. Results from this study present a global view of the dynamic desiccation responses in Salmonella, which will guide future research efforts to control Salmonella in low moisture environments.

Collaborative ring-trial of Dynabeads anti-Salmonella for immunomagnetic separation of stressed Salmonella cells from herbs and spices.

PubMed

Mansfield, L; Forsythe, S

1996-02-01

Eight laboratories participated in a Salmonella detection ring-trial which compared selective enrichment by conventional broths with immunomagnetic separation (IMS) using Dynabeads Anti-Salmonella. Laboratories analyzed six types of herbs and spices that were spiked with one of six freeze-dried Salmonella species. Each herb and spice analysis comprised of 12 samples (25 g each) which had been spiked at three different levels, plus a negative control and stored for one week prior to testing. Out of a total 468 samples analyzed, 195 (41.7%) were positive by both methods. Eighteen samples were positive only by IMS enrichment, in comparison with 19 positive samples by conventional enrichment broths and not IMS. These results confirm the potential use of IMS as an alternative to enrichment broths for Salmonella isolation.

Salmonella enterocolitis

MedlinePlus

... you: Eat foods such as turkey, turkey dressing, chicken, or eggs that have not been cooked well or stored properly Are around family members with a recent salmonella infection Have been in or worked in a ...

Oral vaccination with a live Salmonella Enteritidis/Typhimurium bivalent vaccine in layers induces cross-protection against caecal and internal organ colonization by a Salmonella Infantis strain.

PubMed

Eeckhaut, Venessa; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip

2018-05-01

Salmonella is an important zoonotic agent, and poultry products remain one of the main sources of infection for humans. Salmonella Infantis is an emerging serotype in poultry worldwide, reflected by an increased prevalence in poultry flocks, on broiler meat and in human foodborne illness cases. In the current study, the efficacy of oral administration of a live monovalent Salmonella Enteritidis and a live bivalent Salmonella Enteritidis/Typhimurium vaccine, against a Salmonella Enteritidis and Infantis infection, was determined. Oral administration of the live vaccines to day-old chickens caused a decrease in caecal colonization by Salmonella Enteritidis, but not Infantis, at day 7, when challenged at day 2. Vaccination with the bivalent vaccine at day 1 resulted in a decreased spleen colonization by both Salmonella Infantis and Enteritidis. Twice (at day 1 and week 6) and thrice vaccination (at day 1, week 6 and 16) of laying hens with the bivalent vaccine resulted in a decreased caecal colonization by Salmonella Enteritidis and Infantis, and significantly lower oviduct colonization levels by Salmonella Enteritidis. These data show cross-protection against Salmonella Infantis by oral administration of live vaccine strains belonging to other serogroups. Copyright © 2018 Elsevier B.V. All rights reserved.

Ten years experience of Salmonella infections in Cambridge, UK.

PubMed

Matheson, Nicholas; Kingsley, Robert A; Sturgess, Katherine; Aliyu, Sani H; Wain, John; Dougan, Gordon; Cooke, Fiona J

2010-01-01

Review of all Salmonella infections diagnosed in the Cambridge area over 10 years. All Salmonella enterica isolated in the Clinical Microbiology Laboratory, Addenbrooke's Hospital between 1.1.1999 and 31.12.2008 were included. Patient demographics, serotype and additional relevant details (travel history, resistance-type, phage-type) were recorded. 1003 episodes of Salmonella gastroenteritis were confirmed by stool culture, representing 88 serotypes. Serotypes Enteritidis (59%), Typhimurium (4.7%), Virchow (2.6%), Newport (1.8%) and Braenderup (1.7%) were the 5 most common isolates. There were an additional 37 invasive Salmonella infections (32 blood cultures, 4 tissue samples, 1 CSF). 13/15 patients with Salmonella Typhi or Salmonella Paratyphi isolated from blood or faeces with an available travel history had returned from the Indian subcontinent. 8/10 S. Typhi or Paratyphi isolates tested had reduced susceptibility to fluoroquinolones (MIC > or = 0.125 mg/L). 7/21 patients with non-typhoidal Salmonella bacteraemia were known to be immunosuppressed. This study describes Salmonella serotypes circulating within a defined geographical area over a decade. Prospective molecular analysis of isolates of S. enterica by multi-locus sequence typing (MLST) and single nucleotide polymorphism (SNP) detection will determine the geo-phylogenetic relationship of isolates within our region. 2009 The British Infection Society. Published by Elsevier Ltd. All rights reserved.

Purification, Crystallization And Preliminary X-Ray Analysis of Aminoglycoside-2 ''-Phosphotransferase-Ic [APH(2 '')-Ic] From Enterococcus Gallinarum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrnes, L.J.; /SLAC, SSRL; Badarau, A.

2009-04-30

Bacterial resistance to aminoglycoside antibiotics is primarily the result of deactivation of the drugs. Three families of enzymes are responsible for this activity, with one such family being the aminoglycoside phosphotransferases (APHs). The gene encoding one of these enzymes, aminoglycoside-2{double_prime}-phosphotransferase-Ic [APH(2{double_prime})-Ic] from Enterococcus gallinarum, has been cloned and the wild-type protein (comprising 308 amino-acid residues) and three mutants that showed elevated minimum inhibitory concentrations towards gentamicin (F108L, H258L and a double mutant F108L/H258L) were expressed in Escherichia coli and subsequently purified. All APH(2{double_prime})-Ic variants were crystallized in the presence of 14-20%(w/v) PEG 4000, 0.25 M MgCl{sub 2}, 0.1 M Tris-HClmore » pH 8.5 and 1 mM Mg{sub 2}GTP. The crystals belong to the monoclinic space group C2, with one molecule in the asymmetric unit. The approximate unit-cell parameters are a = 82.4, b = 54.2, c = 77.0 {angstrom}, {beta} = 108.8{sup o}. X-ray diffraction data were collected to approximately 2.15 {angstrom} resolution from an F108L crystal at beamline BL9-2 at SSRL, Stanford, California, USA.« less

Immune Reaction and Survivability of Salmonella Typhimurium and Salmonella Infantis after Infection of Primary Avian Macrophages

PubMed Central

Braukmann, Maria; Methner, Ulrich; Berndt, Angela

2015-01-01

Salmonella serovars are differentially able to infect chickens. The underlying causes are not yet fully understood. Aim of the present study was to elucidate the importance of Salmonella Pathogenicity Island 1 and 2 (SPI-1 and -2) for the virulence of two non-host-specific, but in-vivo differently invasive, Salmonella serovars in conjunction with the immune reaction of the host. Primary avian splenic macrophages were inoculated with Salmonella enterica sub-species enterica serovar (S.) Typhimurium and S. Infantis. The number and viability of intracellular bacteria and transcription of SPI-1 and -2 genes by the pathogens, as well as transcription of immune-related proteins, surface antigen expression and nitric oxide production by the macrophages, were compared at different times post inoculation. After infection, both of the Salmonella serovars were found inside the primary macrophages. Invasion-associated SPI-1 genes were significantly higher transcribed in S. Infantis- than S. Typhimurium-infected macrophages. The macrophages counteracted the S. Infantis and S. Typhimurium infection with elevated mRNA expression of inducible nitric oxide synthase (iNOS), interleukin (IL)-12, IL-18 and lipopolysaccharide-induced tumor necrosis factor alpha factor (LITAF) as well as with an increased synthesis of nitric oxide. Despite these host cell attacks, S. Typhimurium was better able than S. Infantis to survive within the macrophages and transcribed higher rates of the SPI-2 genes spiC, ssaV, sifA, and sseA. The results showed similar immune reactions of primary macrophages after infection with both of the Salmonella strains. The more rapid and stronger transcription of SPI-2-related genes by intracellular S. Typhimurium compared to S. Infantis might be responsible for its better survival in avian primary macrophages. PMID:25811871

Salmonella surrogate reduction using industrial peanut dry roasting parameters

USDA-ARS?s Scientific Manuscript database

Studies were conducted to evaluate the effectiveness of industrial peanut dry roasting parameters in Salmonella reduction using a Salmonella surrogate, Enterococcus faecium, which is slightly more heat tolerant than Salmonella. Runner-type peanuts were inoculated with E. faecium and roasted in a lab...

Saccharomyces boulardii prevention of the hepatic injury induced by Salmonella Enteritidis infection.

PubMed

Wu, Daichao; Teng, Da; Wang, Xiumin; Dai, Changsong; Wang, Jianhua

2014-10-01

Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) is the predominant cause of serovar-associated food-borne outbreaks in many countries and causes significant clinical symptoms of liver injury, enteritis, and diarrheal diseases. Saccharomyces boulardii is used in clinical application for prophylaxis and the treatment of a variety of diseases caused by bacterial infection. We used a mouse model of Salmonella Enteritidis infection, which included pretreatment with S. boulardii, to reveal the protection mechanisms of S. boulardii against Salmonella Enteritidis infection, including the translocation of Salmonella Enteritidis to the liver 10 days after Salmonella Enteritidis challenge, and the colonisation of Salmonella Enteritidis and the formation of hepatic tissue lesions in mice after Salmonella Enteritidis challenge on the 10th day. Compared with Salmonella Enteritidis infection in mice, S. boulardii decreased Salmonella Enteritidis translocation to the liver by 96%, and 99% of Salmonella Enteritidis colonised the cecum on the 10th day. Saccharomyces boulardii also abated hepatic tissue injury caused by the infiltration of neutrophilic granulocytes, lymphocytes, and plasmocytes by decreasing the translocation of Salmonella to the liver. These findings demonstrated that S. boulardii is an effective agent in the prevention of the hepatic injury induced by Salmonella Enteritidis infection in a mouse model.

Salmonella burden in Lebanon.

PubMed

Malaeb, M; Bizri, A R; Ghosn, N; Berry, A; Musharrafieh, U

2016-06-01

Salmonellosis is a disease that represents a major public health concern in both developing and developed countries. The aim of this article is to evaluate the public health burden of Salmonella illness in Lebanon. The current scope of the Salmonella infection problem was assessed in relation to disease incidence and distribution with respect to age, gender and district. Factors that provide a better understanding of the magnitude of the problem were explored and highlighted. Data reported to the Epidemiologic Surveillance Department at the Lebanese Ministry of Public Health between 2001 and 2013 was reviewed. Information obtained was compared to information reported regionally and globally. The estimated true incidence was derived using multipliers from the CDC and Jordan. A literature review of all published data from Lebanon about Salmonella susceptibility/resistance patterns and its serious clinical complications was conducted. The estimated incidence was 13·34 cases/100 000 individuals, most cases occurred in the 20-39 years age group with no significant gender variation. Poor and less developed districts of Lebanon had the highest number of cases and the peak incidence was in summer. Reflecting on the projected incidence derived from the use of multipliers indicates a major discrepancy between what is reported and what is estimated. We conclude that data about Salmonella infection in Lebanon and many Middle Eastern and developing countries lack crucial information and are not necessarily representative of the true incidence, prevalence and burden of illness.

Antimicrobial resistance in zoonotic nontyphoidal Salmonella: an alarming trend?

PubMed

Michael, G B; Schwarz, S

2016-12-01

Zoonotic bacteria of the genus Salmonella have acquired various antimicrobial resistance properties over the years. The corresponding resistance genes are commonly located on plasmids, transposons, gene cassettes, or variants of the Salmonella Genomic Islands SGI1 and SGI2. Human infections by nontyphoidal Salmonella isolates mainly result from ingestion of contaminated food. The two predominantly found Salmonella enterica subsp. enterica serovars in the USA and in Europe are S. Enteritidis and S. Typhimurium. Many other nontyphoidal Salmonella serovars have been implicated in foodborne Salmonella outbreaks. Summary reports of the antimicrobial susceptibility patterns of nontyphoidal Salmonella isolates over time suggest a moderate to low level of antimicrobial resistance and multidrug-resistance. However, serovar-specific analyses showed in part a steady state, a continuous decline, or a recent increase in resistance to certain antimicrobial agents. Resistance to critically important antimicrobial agents, e.g. third-generation cephalosporins and (fluoro)quinolones is part of many monitoring programmes and the corresponding results confirm that extended-spectrum β-lactamases are still rarely found in nontyphoidal Salmonella serovars, whereas resistance to (fluoro)quinolones is prevalent at variable frequencies among different serovars from humans and animals in different countries. Although it is likely that nontyphoidal Salmonella isolates from animals represent a reservoir for resistance determinants, it is mostly unknown where and when Salmonella isolates acquired resistance properties and which exchange processes have happened since then. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Reduction of Salmonella in ground chicken using a bacteriophage.

PubMed

Grant, Ar'Quette; Parveen, Salina; Schwarz, Jurgen; Hashem, Fawzy; Vimini, Bob

2017-08-01

This study's goal was to ascertain the effectiveness of a commercially available Salmonella bacteriophage during ground chicken production focusing on: water source, different Salmonella serovars, and time. Salmonella-free boneless, skinless chicken meat was inoculated with 4.0 Log CFU/cm2 of either a cocktail of 3 Salmonella isolates derived from ground chicken (GC) or a cocktail of 3 Salmonella strains not isolated from ground chicken (non-GC). Bacteriophages were spread onto the chicken using sterile tap or filtered water for 30 min or 8 h. Salmonella was recovered using standard plating method. Greater Salmonella reduction was observed when the bacteriophage was diluted in sterile tap water than in sterile filtered water: 0.39 Log CFU/cm2 and 0.23 Log CFU/cm2 reduction after 30 min, respectively (P < 0.05). The non-GC isolates showed reductions of 0.71 Log CFU/cm2 and 0.90 Log CFU/cm2 after 30 min and 8 h, respectively (P < 0.05). The GC isolates were less sensitive to the bacteriophage: 0.39 Log CFU/cm2 and 0.67 Log CFU/cm2 reductions after 30 min and 8 h, respectively (P < 0.05). In conclusion, bacteriophage reduction was dependent on water used to dilute the bacteriophage, Salmonella's susceptibility to the bacteriophage, and treatment time. © 2017 Poultry Science Association Inc.

Initial contamination of chicken parts with Salmonella at retail and cross-contamination of cooked chicken with Salmonella from raw chicken during meal preparation.

PubMed

Oscar, T P

2013-01-01

The current study was undertaken to acquire data on contamination of chicken parts with Salmonella at retail and to acquire data on cross-contamination of cooked chicken with Salmonella from raw chicken during meal preparation. Whole raw chickens (n = 31) were obtained from local retail stores and cut into two wings, two breasts without skin or bones, two thighs, and two drumsticks. Data for cross-contamination were obtained by cutting up a sterile, cooked chicken breast with the same board and knife used to cut up the raw chicken. The board, knife, and latex gloves used by the food handler were not rinsed or washed before cutting up the sterile, cooked chicken breast, thus providing a worst-case scenario for cross-contamination. Standard curves for the concentration of Salmonella bacteria in 400 ml of buffered peptone water after 6 h of incubation of chicken parts as a function of the initial log number of Salmonella bacteria inoculated onto chicken parts were developed and used to enumerate Salmonella bacteria. Standard curves were not affected by the type of chicken part but did differ (P < 0.05) among the five isolates of Salmonella examined. Consequently, Salmonella bacteria were enumerated on naturally contaminated chicken parts using a standard curve developed with the serotype of Salmonella that was isolated from the original sample. The prevalence of contamination was 3 % (4 of 132), whereas the incidence of cross-contamination was 1.8 % (1 of 57). The positive chicken parts were a thigh from chicken 4, which contained 3 CFU of Salmonella enterica serotype Kentucky, and both wings, one thigh, and one cooked breast portion from chicken 15, which all contained 1 CFU of serotype 8,20:-:z(6). These results indicated that the poultry industry is providing consumers in the studied area with chicken that has a low prevalence and low number of Salmonella bacteria at retail and that has a low incidence and low level of cross-contamination of cooked chicken with

Survival and growth of Salmonella in salsa and related ingredients.

PubMed

Ma, Li; Zhang, Guodong; Gerner-Smidt, Peter; Tauxe, Robert V; Doyle, Michael P

2010-03-01

A large outbreak of Salmonella Saintpaul associated with raw jalapeño peppers, serrano peppers, and possibly tomatoes was reported in the United States in 2008. During the outbreak, two clusters of illness investigated among restaurant patrons were significantly associated with eating salsa. Experiments were performed to determine the survival and growth characteristics of Salmonella in salsa and related major ingredients, i.e., tomatoes, jalapeño peppers, and cilantro. Intact and chopped vegetables and different formulations of salsas were inoculated with a five-strain mixture of Salmonella and then stored at 4, 12, and 21 degrees C for up to 7 days. Salmonella populations were monitored during storage. Salmonella did not grow, but survived on intact tomatoes and jalapeño peppers, whereas significant growth at 12 and 21 degrees C was observed on intact cilantro. In general, growth of Salmonella occurred in all chopped vegetables when stored at 12 and 21 degrees C, with chopped jalapeño peppers being the most supportive of Salmonella growth. Regardless of differences in salsa formulation, no growth of Salmonella (initial inoculation ca. 3 log CFU/g) was observed in salsa held at 4 degrees C; however, rapid or gradual decreases in Salmonella populations were only observed in formulations that contained both fresh garlic and lime juice. Salmonella grew at 12 and 21 degrees C in salsas, except for those formulations that contained both fresh garlic and lime juice, in which salmonellae were rapidly or gradually inactivated, depending on salsa formulation. These results highlight the importance of preharvest pathogen contamination control of fresh produce and proper formulation and storage of salsa.

Direct feeding of microencapsulated bacteriophages to reduce Salmonella colonization in pigs

USDA-ARS?s Scientific Manuscript database

Salmonella shedding often increases in pigs following pre-slaughter transportation and/or lairage. We previously showed that administering anti-Salmonella bacteriophages to pigs by gavage significantly reduced Salmonella colonization when the pigs were exposed to a Salmonella-contaminated pen. In ...

Modeling of Salmonella Contamination in the Pig Slaughterhouse.

PubMed

Swart, A N; Evers, E G; Simons, R L L; Swanenburg, M

2016-03-01

In this article we present a model for Salmonella contamination of pig carcasses in the slaughterhouse. This model forms part of a larger QMRA (quantitative microbial risk assessment) on Salmonella in slaughter and breeder pigs, which uses a generic model framework that can be parameterized for European member states, to describe the entire chain from farm-to-consumption and the resultant human illness. We focus on model construction, giving mathematical formulae to describe Salmonella concentrations on individual pigs and slaughter equipment at different stages of the slaughter process. Variability among individual pigs and over slaughterhouses is incorporated using statistical distributions, and simulated by Monte Carlo iteration. We present the results over the various slaughter stages and show that such a framework is especially suitable to investigate the effect of various interventions. In this article we present the results of the slaughterhouse module for two case study member states. The model outcome represents an increase in average prevalence of Salmonella contamination and Salmonella numbers at dehairing and a decrease of Salmonella numbers at scalding. These results show good agreement when compared to several other QMRAs and microbiological studies. © 2016 Society for Risk Analysis.

Sources of Salmonellae in broiler chickens in Ontario.

PubMed Central

Hacking, W C; Mitchell, W R; Carlson, H C

1978-01-01

Sources of Salmonellae infecting broiler chicken flocks in Ontario were investigated from July, 1975 to April, 1976. Three broiler flocks were investigated on each of four farms which received chicks from a common hatchery. Samples of feed and new litter were preenriched in nonselective broth subcultured to Salmonella-selective enrichment broth and plated on Salmonella-selective differential agar.Samples of used litter, water, culled chicks, insects, mice, wild birds and environmental swabs were not cultured initially in the nonselective broth. Fecal samples from principal and occasional flock attendants were examined for Samonellae. Salmonella infection, as judged by contaminated flock litter was detected in six flocks on two of the farms while the flocks on the other farms remained negative. Salmonellae were isolated from 23 of 412 feed samples (nine serotypes), six of 35 new wood shaving samples (four serotypes), one of 29 pools of culled chick viscera (one serotype) and 44 of 267 used litter samples (14 serotypes). These results indicate that broiler chicken flocks were infected with diverse Salmonellae introduced in day old chicks, pelleted feeds, wood shavings and residual contamination from the preceding flock. PMID:743597

Assessment of 2 Salmonella enterica serovar Typhimurium-based vaccines against necrotic enteritis in reducing colonization of chickens by Salmonella serovars of different serogroups.

PubMed

Jiang, Yanfen; Kulkarni, Raveendra R; Parreira, Valeria R; Poppe, Cornelius; Roland, Kenneth L; Prescott, John F

2010-10-01

This study assessed the protective efficacy of oral vaccination with 2 experimental attenuated Salmonella Typhimurium-vectored vaccines for necrotic enteritis in protecting chickens against intestinal colonization by common serovars of Salmonella belonging to the 4 major serogroups affecting chickens. Birds were vaccinated orally with 1 × 10⁸ colony-forming units (CFU) of 1 of the vaccine strains χ9241 and χ9352, which express a plasmid-encoded partial recombinant hypothetical protein gene (tHP) of Clostridium perfringens, at days 1 and 7 of age, and then were challenged at 14 d of age with 10⁶ CFU of Salmonella serovars Anatum, Enteritidis, Heidelberg, Kentucky, or Typhimurium (representative serovars of serogroups B, C, D, and E). Birds were necropsied at 4 wk of age, and samples were collected to determine reduction in tissue and intestinal colonization. The chickens vaccinated with χ9241-tHP showed reduced colonization by Salmonella Enteritidis (serogroup D) and by Salmonella Heidelberg and Salmonella Typhimurium (serogroup B) compared with the control birds. No reduction in colonization was observed in the chickens vaccinated with χ9352-tHP. There was an association between the efficacy of these vaccine strains in protecting against necrotic enteritis, assessed on an earlier occasion, and their efficacy in protecting against Salmonella colonization. Thus, the choice of an attenuated Salmonella Typhimurium vaccine vector for delivery of heterologous antigens to chickens should be based partly on the vaccine's value in protecting against colonization by serovars within serogroups B and D. Such vectors would have the additional benefit of reducing colonization of important Salmonella serovars.

Assessment of 2 Salmonella enterica serovar Typhimurium-based vaccines against necrotic enteritis in reducing colonization of chickens by Salmonella serovars of different serogroups

PubMed Central

Jiang, Yanfen; Kulkarni, Raveendra R.; Parreira, Valeria R.; Poppe, Cornelius; Roland, Kenneth L.; Prescott, John F.

2010-01-01

This study assessed the protective efficacy of oral vaccination with 2 experimental attenuated Salmonella Typhimurium-vectored vaccines for necrotic enteritis in protecting chickens against intestinal colonization by common serovars of Salmonella belonging to the 4 major serogroups affecting chickens. Birds were vaccinated orally with 1 × 108 colony-forming units (CFU) of 1 of the vaccine strains χ9241 and χ9352, which express a plasmid-encoded partial recombinant hypothetical protein gene (tHP) of Clostridium perfringens, at days 1 and 7 of age, and then were challenged at 14 d of age with 106 CFU of Salmonella serovars Anatum, Enteritidis, Heidelberg, Kentucky, or Typhimurium (representative serovars of serogroups B, C, D, and E). Birds were necropsied at 4 wk of age, and samples were collected to determine reduction in tissue and intestinal colonization. The chickens vaccinated with χ9241-tHP showed reduced colonization by Salmonella Enteritidis (serogroup D) and by Salmonella Heidelberg and Salmonella Typhimurium (serogroup B) compared with the control birds. No reduction in colonization was observed in the chickens vaccinated with χ9352-tHP. There was an association between the efficacy of these vaccine strains in protecting against necrotic enteritis, assessed on an earlier occasion, and their efficacy in protecting against Salmonella colonization. Thus, the choice of an attenuated Salmonella Typhimurium vaccine vector for delivery of heterologous antigens to chickens should be based partly on the vaccine’s value in protecting against colonization by serovars within serogroups B and D. Such vectors would have the additional benefit of reducing colonization of important Salmonella serovars. PMID:21197226

Coconut and Salmonella Infection

PubMed Central

Schaffner, Carl P.; Mosbach, Klaus; Bibit, Venuso C.; Watson, Colin H.

1967-01-01

Raw, unprocessed coconut supports the growth of salmonellae as well as that of other enteric bacteria, salmonellae being particularly resistant to subsequent desiccation. Original contamination is not due to carriers or to polluted water supplies, but to contact with bacteria-containing soils followed by dispersion via infected coconut milk and shells. Pasteurization of raw coconut meat in a water bath at 80 C for 8 to 10 min effectively killed such bacteria, did not injure the product, and provided a prophylactic method now widely used by the coconut industry. PMID:5340650

Salmonella species isolated from animal feed in Iraq.

PubMed Central

Al-Hindawi, N; Taha, R R

1979-01-01

Of 700 animal feed samples, 32 (4.5%) harbored Salmonella. The highest percentage of contamination was found in sheep feed and local protein. A total of 17 Salmonella serotypes were identified. The most frequent serotypes were Salmonella meleagridis. S. bornum, S. montevideo, and S. drypool. S. bornum was isolated for the first time in Iraq and from both local feed and its ingredients. The common somatic group found was that of Salmonella group C; then came groups E, G, B, and D. Three serotypes (S. enteritidis, S. california, and S. muenchen) seemed to form a link of infection among feed, food, patients, and carriers. PMID:453836

Salmonella Typhimurium pneumonia in a patient with multiple myeloma.

PubMed

Khan, Sadia; Kumar, V Anil; Sidharthan, Neeraj; Mehta, Asmita; Backer, Binita; Dinesh, Kavitha R

2015-04-01

Pneumonia due to non-typhoidal Salmonella is a rarely reported entity. A fatal case of Salmonella pneumonia is reported here where Salmonella Typhimurium was isolated from the endotracheal aspirate and blood culture. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Isolation of Salmonella Virchow from a fruit bat (Pteropus giganteus).

PubMed

Islam, Ausraful; Mikolon, Andrea; Mikoleit, Matthew; Ahmed, Dilruba; Khan, Salah Udddin; Sharker, M A Yushuf; Hossain, M Jahangir; Islam, Ariful; Epstein, Jonathan H; Zeidner, Nord; Luby, Stephen P

2013-12-01

Detection of zoonotic pathogens carried by bats is important both for understanding disease ecology and for developing preventive measures. Pteropus fruit bats have been identified as potential carriers of Salmonella enterica serotype Typhi. A cross-sectional study was conducted to determine the prevalence of Salmonella Typhi and other Salmonella serotypes in Pteropus giganteus fruit bats in Bangladesh. Rectal swabs were collected from 302 bats and cultured for Salmonella species. The bats were trapped in three districts (Faridpur, Rajbari, and Cox's Bazar). Salmonella Typhi was not found but one juvenile female bat from Faridpur district was positive for Salmonella Virchow. Close associations between frugivorous bats, humans, and livestock in rural Bangladesh make it likely that the bat was infected by consuming contaminated water.

Comparing validation of four ELISA-systems for detection of Salmonella derby- and Salmonella infantis-infected pigs.

PubMed

Roesler, Uwe; Szabo, Istvan; Matthies, Claudia; Albrecht, Kerstin; Leffler, Martin; Scherer, Kathrin; Nöckler, Karsten; Lehmann, Jörg; Methner, Ulrich; Hensel, Andreas; Truyen, Uwe

2011-01-01

The objective of this study was the comparative evaluation of four indirect Salmonella ELISA tests at study time approved in Germany to detect Salmonella infection in pigs.Three tests are based on a LPS-antigen mix and directed against specific IgG antibodies. The fourth test is based on a purified S. Typhimurium whole-cell lysate antigen and discriminates between Salmonella-specific IgM-, IgA-, and IgG- antibodies. In a longitudinal study, two groups of six weeks old hybrid piglets were orally infected with a porcine S. Infantis or S. Derby strain. Clinical and bacteriological parameters were monitored weekly during an observation period of 130 days after infection and serum samples were investigated in parallel with the respective ELISAs. Apparently, the LPS-based ELISA systems used in this study failed to recognize S. Infantis-infected pigs although those animals shed the pathogen in high amounts throughout the study until day 81 post infection (p. i.). In contrast, the isotype-specific Salmonella Typhimurium whole-cell-lysate based ELISA was capable of detecting Salmonella-infected pigs from day ten p. i. at all tested serotypes and revealed the highest sensitivity in detection of S. Infantis-infected pigs. Furthermore, it became apparent that the often used surveillance cut-off value of 40 OD% is not appropriate for intra-vitam detection of S. Infantis- and S. Derby-infected pigs. In contrast, the cut-off values of the ELISAs given by the suppliers result in considerable higher detection rates.

Chasing Salmonella Typhimurium in free range egg production system.

PubMed

Chousalkar, Kapil; Gole, Vaibhav; Caraguel, Charles; Rault, Jean-Loup

2016-08-30

Free range production systems are becoming a major source of egg production in Australia and worldwide. This study investigated shedding and ecology of Salmonella Typhimurium and Salmonella species in a free range layer flock, wild birds and foxes in the vicinity of the free range farm in different seasons. Shedding of Salmonella was significantly higher in summer. Within the shed, overall, Salmonella prevalence was highest in dust. Corticosterone level in faeces was highest in spring and lowest in winter. There was no direct association between the Salmonella shedding (MPN/gm) and corticosterone levels in faeces. Salmonella Typhimurium MLVA types isolated from fox and wild birds were similar to MLVA types isolated from layer flock and reported during human food borne illness. Wild birds and foxes appear to play an important role in S. Typhimurium ecology and food safety. Environmental factors could play a role in evolution of S. Typhimurium in free range environment. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Examination of predictors of Salmonella enterica contamination in cattle feedlot environments

USDA-ARS?s Scientific Manuscript database

Objective: To identify a “predictor” or “environmental marker” that can be used to estimate Salmonella prevalence in a given feedlot environment. Further, to examine the correlation between environmental Salmonella contamination, Salmonella fecal shedding status, and prevalence of Salmonella in per...

Toward Molecular Level of the “Salmonella-Victim” Ecology, Genetics, and Evolution

PubMed Central

Rumyantsev, S.N.

2004-01-01

Bacteria of the Salmonella genus are polypathogenic agents that can affect both men and animals, causing devastating and fatal illness. Despite considerable immunological, epidemiological, and genetic efforts, and increased understanding of how the Salmonella infection develops, many key questions concerning Salmonella infection remain unanswered. Salmonella can be carried as harmless commensals in some sectors of the population. In some individuals, however, the same microbes cause illness while others display immunity to primary Salmonella infection. Nothing is known about the molecular base of the Salmonella pathogenicity. Even the ability of Salmonella to destroy the victims cells has been the subject of century-long discussions. In this article, some key findings concerning ecology, molecular ecology, and cell level of the Salmonella infection genetics are summarized and interpreted from the viewpoint of evolutionary theory with certitude that this approach can help to decipher the undiscovered secrets of Salmonella infections epidemiology and pathogenesis, as well as the clinical course and severity, and to select ways for fighting against Salmonella. PMID:15105959

Salmonella paratyphi spondylitis: a case report.

PubMed

Kumar, Pradeep; Mahmoodi, Seyed Mohsen; Kalaparambil Moosa, Nooruddin; Edgar, Michael; Samt, Hussain Al; Hussain, Riyaz Amirali

2008-05-01

This is a case report of acute L3/4 vertebral osteomyelitis due to Salmonella paratyphi A confirmed by culture from vertebral needle biopsy. From a review of the literature this is the first reported case with bacteriological confirmation. The rarity of Salmonella paratyphi spondylitis and the options for treatment are discussed.

Preexisting Salmonella-specific immunity interferes with the subsequent development of immune responses against the Salmonella strains delivering H9N2 hemagglutinin.

PubMed

Hajam, Irshad Ahmed; Lee, John Hwa

2017-06-01

Recombinant Salmonella strains expressing foreign heterologous antigens have been extensively studied as promising live vaccine delivery vehicles. In this study, we constructed attenuated smooth (S-HA) and rough (R-HA) Salmonella strains expressing hemagglutinin (HA) of H9N2, a low pathogenic avian influenza A virus. We then investigated the HA-specific immune responses following oral immunization with either S-HA or R-HA strain in chicken model. We further examined the effects of the preexisting anti-Salmonella immunity on the subsequent elicitation of the HA and the Salmonella ompA specific immune responses. Our results showed that primary immunization with either the S-HA or the R-HA strain elicited comparable HA-specific immune responses and the responses were significantly (p<0.05) higher compared to the Salmonella vector control. When chickens were pre-immunized with the smooth Salmonella carrier alone and then vaccinated with either S-HA or R-HA strain 3, 6 and 9 weeks later, respectively, significant reductions were seen for HA-specific immune responses at week 6, a point which corresponded to the peak of the primary Salmonella-specific antibody responses. No reductions were seen at week 3 and 9, albeit, the HA-specific immune responses were boosted at week 9, a point which corresponded to the lowest primary Salmonella-specific antibody responses. The ompA recall responses remain refractory at week 3 and 6 following deliberate immunization with the carrier strain, but were significantly (p<0.05) increased at week 9 post-primary immunization. We conclude that preexisting anti-Salmonella immunity inhibits antigen-specific immune responses and this effect could be avoided by carefully selecting the time point when carrier-specific immune responses are relatively low. Copyright © 2017 Elsevier B.V. All rights reserved.

Fate of Salmonella Typhimurium in laboratory-scale drinking water biofilms.

PubMed

Schaefer, L M; Brözel, V S; Venter, S N

2013-12-01

Investigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein and thus allows in situ detection of undisturbed cells and is ideally suited for monitoring Salmonella in biofilms. The fate and persistence of non-typhoidal Salmonella in simulated drinking water biofilms was investigated. The ability of Salmonella to form biofilms in monoculture and the fate and persistence of Salmonella in a mixed aquatic biofilm was examined. In monoculture S. Typhimurium formed loosely structured biofilms. Salmonella colonized established multi-species drinking water biofilms within 24 hours, forming micro-colonies within the biofilm. S. Typhimurium was also released at high levels from the drinking water-associated biofilm into the water passing through the system. This indicated that Salmonella could enter into, survive and grow within, and be released from a drinking water biofilm. The ability of Salmonella to survive and persist in a drinking water biofilm, and be released at high levels into the flow for recolonization elsewhere, indicates the potential for a persistent health risk to consumers once a network becomes contaminated with this bacterium.

Salmonella Infections

USDA-ARS?s Scientific Manuscript database

Infections with bacteria of the genus Salmonella are responsible for both acute and chronic poultry diseases. These diseases cause economically significant losses for poultry producers in many nations and absorb large investments of public and private resources in testing and control efforts. Infect...

Salmonella infection and carriage in reptiles in a zoological collection.

PubMed

Clancy, Meredith M; Davis, Meghan; Valitutto, Marc T; Nelson, Kenrad; Sykes, John M

2016-05-01

OBJECTIVE To identify important subspecies and serovars of Salmonella enterica in a captive reptile population and clinically relevant risk factors for and signs of illness in Salmonella-positive reptiles. DESIGN Retrospective cross-sectional study. ANIMALS 11 crocodilians (4 samples), 78 snakes (91 samples), 59 lizards (57 samples), and 34 chelonians (23 samples) at the Bronx Zoo from 2000 through 2012. PROCEDURES Data pertaining to various types of biological samples obtained from reptiles with positive Salmonella culture results and the reptiles themselves were analyzed to determine period prevalence of and risk factors for various Salmonella-related outcomes. RESULTS Serovar distribution differences were identified for sample type, reptile phylogenetic family, and reptile origin and health. Salmonella enterica subsp enterica was the most common subspecies in Salmonella cultures (78/175 [45%]), identified across all reptilian taxa. Salmonella enterica subsp diarizonae was also common (42/175 [24%]) and was recovered almost exclusively from snakes (n = 33), many of which had been clinically ill (17). Clinically ill reptiles provided 37% (64) of Salmonella cultures. Factors associated with an increased risk of illness in reptiles with a positive culture result were carnivorous diet and prior confiscation. Snakes had a higher risk of illness than other reptile groups, whereas lizards had a lower risk. Bony changes, dermatitis, and anorexia were the most common clinical signs. CONCLUSIONS AND CLINICAL RELEVANCE This study provided new information on Salmonella infection or carriage and associated clinical disease in reptiles. Associations identified between serovars or subspecies and reptile groups or clinical disease can guide management of Salmonella-positive captive reptiles.

Molecular characterization of Salmonella Paratyphi B dT+ and Salmonella Heidelberg from poultry and retail chicken meat in Colombia by pulsed-field gel electrophoresis

USDA-ARS?s Scientific Manuscript database

Salmonella Paratyphi B dT+ variant (also termed Salmonella Java) and Salmonella Heidelberg are human pathogens frequently isolated from poultry. As a step towards implementing the Colombian Integrated Program for Antimicrobial Resistant Surveillance (COIPARS), this study characterized molecular patt...

Salmonella serotypes in reptiles and humans, French Guiana.

PubMed

Gay, Noellie; Le Hello, Simon; Weill, François-Xavier; de Thoisy, Benoit; Berger, Franck

2014-05-14

In French Guiana, a French overseas territory located in the South American northern coast, nearly 50% of Salmonella serotypes isolated from human infections belong to serotypes rarely encountered in metropolitan France. A reptilian source of contamination has been investigated. Between April and June 2011, in the area around Cayenne, 151 reptiles were collected: 38 lizards, 37 snakes, 32 turtles, 23 green iguanas and 21 caimans. Cloacal swab samples were collected and cultured. Isolated Salmonella strains were identified biochemically and serotyped. The overall carriage frequency of carriage was 23.2% (95% confidence interval: 16.7-30.4) with 23 serotyped strains. The frequency of Salmonella carriage was significantly higher for wild reptiles. Near two-thirds of the Salmonella serotypes isolated from reptiles were also isolated from patients in French Guiana. Our results highlight the risk associated with the handling and consumption of reptiles and their role in the spread of Salmonella in the environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Salmonella paratyphi spondylitis: a case report

PubMed Central

Mahmoodi, Seyed Mohsen; Kalaparambil Moosa, Nooruddin; Edgar, Michael; Samt, Hussain Al; Hussain, Riyaz Amirali

2007-01-01

This is a case report of acute L3/4 vertebral osteomyelitis due to Salmonella paratyphi A confirmed by culture from vertebral needle biopsy. From a review of the literature this is the first reported case with bacteriological confirmation. The rarity of Salmonella paratyphi spondylitis and the options for treatment are discussed. PMID:18008092

[Salmonella spp. strains resistant to drugs].

PubMed

Białucha, Agata; Kozuszko, Sylwia; Gospodarek, Eugenia

2010-01-01

The aim of the study was retrospective analysis of Salmonella spp. strains isolated from patients of State Infectious Diseases Observatory Hospital of T. Browicz in Bydgoszcz (SZAK) and University of dr. A. Jurasz in Bydgoszcz (SU CM UMK) in 2006-2009. The percentages of Salmonella spp. strains resistant to at least one drug were: 19,0% in 2006, 12,5% in 2007, 50,6% in 2008 and 43,8% in the first half of 2009 year. The highest number of Salmonella spp. strains resistant to drugs were isolated from stool (96,7%) and from patients of SZAK (83,3%). Among all isolated Salmonella spp. strains resistant to drugs the highest percentage were S. enterica serovar Enteritidis (56,7%). Among S. enterica bacilli predominated resitant phenotypes to ampicillin, amoxicillin, chloramphenicol and nalidixic acid. The increasing number of strains resistant to ciprofloxacin (0,0 - 26,7%) and high percentage of strains resistant to nalidixic acid (97,3%) were noted. Decreasing resistance to chloramphenicol was observed in our study (54,5 - 14,3%).

Salmonellae Associated with Further-processed Turkey Products1

PubMed Central

Bryan, Frank L.; Ayres, John C.; Kraft, Allen A.

1968-01-01

“Further-processed” turkey products, prepared from chilled, eviscerated, and thawed carcasses at two commercial turkey-processing plants, were evaluated, for the presence of salmonellae. These organisms were isolated from swab samples from 12% of chilled, eviscerated turkey carcasses, 27% of finished products, and 24% of processing equipment. The same serotypes as those found throughout a plant on any one visit were recovered from 31% of rinse-samples taken from hands and gloves of processing personnel. Salmonellae were found in samples taken on 37 of 48 visits; a greater number of recoveries were made on days when freshly killed turkeys were processed (87%) than when frozen-defrosted carcasses were processed (59%). The predominant serotype isolated from meat and environment usually changed from visit to visit. Salmonella sandiego and Salmonella anatum were the most frequent among 23 serotypes recovered. Most of the isolated serotypes are commonly associated with turkeys and have been incriminated as causative agents of human salmonellosis. The implication is that further-processed turkey products, if inadequately cooked by the consumer and if improperly refrigerated between the time of manufacture and consumption, could directly transmit salmonellae. These same products might also contaminate other foods by introducing salmonellae into food-preparation areas. PMID:5688832

The effect of feeding diets containing avoparcin on the excretion of salmonellas by chickens experimentally infected with natural sources of salmonella organisms.

PubMed Central

Barrow, P. A.; Smith, H. W.; Tucker, J. F.

1984-01-01

Chickens were readily infected with salmonella organisms when fed diets containing unsterilized bone-meal or provided with drinking water containing a suspension of natural salmonella infected chicken faeces. When fed diets containing avoparcin at concentrations of 10 or 100 mg/kg chickens infected in these ways excreted larger numbers of salmonellas for longer periods than did chickens fed a nonmedicated diet. PMID:6512249

Seasonal stability of Cladophora-associated Salmonella in Lake Michigan watersheds.

PubMed

Byappanahalli, Muruleedhara N; Sawdey, Richard; Ishii, Satoshi; Shively, Dawn A; Ferguson, John A; Whitman, Richard L; Sadowsky, Michael J

2009-02-01

The bacterial pathogens Shigella, Salmonella, Campylobacter, and shiga toxin-producing E. coli (STEC) were recently found to be associated with Cladophora growing in southern Lake Michigan. Preliminary results indicated that the Salmonella strains associated with Cladophora were genetically identical to each other. However, because of the small sample size (n=37 isolates) and a lack of information on spatial-temporal relationships, the nature of the association between Cladophora and Salmonella remained speculative. In this study, we investigated the population structure and genetic relatedness of a large number of Cladophora-borne Salmonella isolates from Lake Michigan (n=133), as well as those isolated from stream and lake water (n=31), aquatic plants (n=8), and beach sands and sediments (n=8) from adjacent watersheds. Salmonella isolates were collected during 2005-2007 between May and August from Lake Michigan beachsheds in Wisconsin, Illinois, and Indiana. The genetic relatedness of Salmonella isolates was examined by using the horizontal, fluorophore-enhanced rep-PCR (HFERP) DNA fingerprinting technique. While the Salmonella isolates associated with Cladophora exhibited a high degree of genetic relatedness (>or=92% similarity), the isolates were not all genetically identical. Spatial and temporal relationships were evident in the populations examined, with tight clustering of the isolates both by year and location. These findings suggest that the relationship between Salmonella and Cladophora is likely casual and is related to input sources (e.g. wastewater, runoff, birds) and the predominant Salmonella genotype surviving in the environment during a given season. Our studies indicate that Cladophora is likely an important reservoir for Salmonella and other enteric bacterial pathogens in Lake Michigan beachsheds, which in turn may influence nearshore water quality.

Seasonal stability of Cladophora-associated Salmonella in Lake Michigan watersheds

USGS Publications Warehouse

Byappanahalli, M.N.; Sawdey, R.; Ishii, S.; Shively, D.A.; Ferguson, J.A.; Whitman, R.L.; Sadowsky, M.J.

2009-01-01

The bacterial pathogens Shigella, Salmonella, Campylobacter, and shiga toxin-producing E. coli (STEC) were recently found to be associated with Cladophora growing in southern Lake Michigan. Preliminary results indicated that the Salmonella strains associated with Cladophora were genetically identical to each other. However, because of the small sample size (n = 37 isolates) and a lack of information on spatial-temporal relationships, the nature of the association between Cladophora and Salmonella remained speculative. In this study, we investigated the population structure and genetic relatedness of a large number of Cladophora-borne Salmonella isolates from Lake Michigan (n = 133), as well as those isolated from stream and lake water (n = 31), aquatic plants (n = 8), and beach sands and sediments (n = 8) from adjacent watersheds. Salmonella isolates were collected during 2005-2007 between May and August from Lake Michigan beachsheds in Wisconsin, Illinois, and Indiana. The genetic relatedness of Salmonella isolates was examined by using the horizontal, fluorophore-enhanced rep-PCR (HFERP) DNA fingerprinting technique. While the Salmonella isolates associated with Cladophora exhibited a high degree of genetic relatedness (???92% similarity), the isolates were not all genetically identical. Spatial and temporal relationships were evident in the populations examined, with tight clustering of the isolates both by year and location. These findings suggest that the relationship between Salmonella and Cladophora is likely casual and is related to input sources (e.g. wastewater, runoff, birds) and the predominant Salmonella genotype surviving in the environment during a given season. Our studies indicate that Cladophora is likely an important reservoir for Salmonella and other enteric bacterial pathogens in Lake Michigan beachsheds, which in turn may influence nearshore water quality. ?? 2008 Elsevier Ltd.

Diffuse abdominal gallium-67 citrate uptake in salmonella infections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garty, I.; Koren, A.

1987-11-01

Two pediatric patients with salmonella infections (one with typhoid fever and the second with salmonella C2 gastroenteritis), had a diffuse abdominal uptake of Ga-67 citrate. The possible explanation for this finding is discussed. Salmonella infection should be included as a cause in the differential diagnosis of diffuse accumulation of Ga-67 citrate.

Prevention of Salmonella cross-contamination in an oilmeal manufacturing plant.

PubMed

Morita, T; Kitazawa, H; Iida, T; Kamata, S

2006-08-01

The mechanisms of Salmonella contamination in an oilmeal plant were investigated and the basic data were collected in order to achieve control of Salmonella in oilmeal. Salmonella was detected in all contamination vectors and environmental factors investigated, namely: operators, processing floor, dust in the air and rodents. In particular, high concentrations of Salmonella were detected on the processing floor of the manufacturing area, which has high oil content. Steam was the most effective disinfection method used for the processing floor, as the effects of heat sterilization and disinfection may work in tandem. In addition, restricting the movement of operators of the production chain remarkably reduced Salmonella contamination, even in areas of otherwise high contamination. Within the oilmeal plant, high Salmonella contamination rates for the processing floor represent the greatest risk of contamination of oilmeal via operators, dust in the air and rodents. Therefore, control of the processing floor is the most important means for reducing the oilmeal contamination rate. Specific Salmonella control methods for oilmeal plants have been established.

Recombinant Salmonella Bacteria Vectoring HIV/AIDS Vaccines

PubMed Central

Chin’ombe, Nyasha; Ruhanya, Vurayai

2013-01-01

HIV/AIDS is an important public health problem globally. An affordable, easy-to-deliver and protective HIV vaccine is therefore required to curb the pandemic from spreading further. Recombinant Salmonella bacteria can be harnessed to vector HIV antigens or DNA vaccines to the immune system for induction of specific protective immunity. These are capable of activating the innate, humoral and cellular immune responses at both mucosal and systemic compartments. Several studies have already demonstrated the utility of live recombinant Salmonella in delivering expressed foreign antigens as well as DNA vaccines to the host immune system. This review gives an overview of the studies in which recombinant Salmonella bacteria were used to vector HIV/AIDS antigens and DNA vaccines. Most of the recombinant Salmonella-based HIV/AIDS vaccines developed so far have only been tested in animals (mainly mice) and are yet to reach human trials. PMID:24478808

The occurrence of Salmonella in airline meals.

PubMed

Hatakka, M; Asplund, K

1993-01-01

The occurrence of Salmonella in airline meals was studied in 1989-1992. Samples were collected from flight kitchens in 29 countries. The material consisted of 400 cold dishes and 1,288 hot dishes as well as salads, cheese plates and deserts. Total number of samples was 2211. Salmonella spp. were isolated from 6 samples; 1 contaminated sample was a cold dish prepared in Bangkok, 1 was a hot dish prepared in Mombasa and the remaining 4 contaminated samples were hot dishes prepared within one week in Beijing. The isolated serotypes were S. ohio, S. manchester and S. braenderup. The contaminated cold dish prepared by a flight kitchen in Bangkok was found to be connected with a Salmonella outbreak which occurred in Finland in 1990. Cold airline dishes containing food of animal origin seems to be more risky as a source of Salmonella infections among airline passengers.

Nutritional strategies to combat Salmonella in mono-gastric food animal production.

PubMed

Berge, A C; Wierup, M

2012-04-01

Nutritional strategies to minimize Salmonella in food animal production are one of the key components in producing safer food. The current European approach is to use a farm-to-fork strategy, where each sector must implement measures to minimize and reduce Salmonella contamination. In the pre-harvest phase, this means that all available tools need to be used such as implementation of biosecurity measures, control of Salmonella infections in animals at the farm as well as in transport and trade, optimal housing and management including cleaning, disinfection procedures as well as efforts to achieve Salmonella-free feed production. This paper describes some nutritional strategies that could be used in farm control programmes in the major mono-gastric food production animals: poultry and pigs. Initially, it is important to prevent the introduction of Salmonella onto the farm through Salmonella-contaminated feed and this risk is reduced through heat treatment and the use of organic acids and their salts and formaldehyde. Microbiological sampling and monitoring for Salmonella in the feed mills is required to minimize the introduction of Salmonella via feed onto the farm. In addition, feed withdrawal may create a stressful situation in animals, resulting in an increase in Salmonella shedding. Physical feed characteristics such as coarse-ground meal to pigs can delay gastric emptying, thereby increasing the acidity of the gut and thus reducing the possible prevalence of Salmonella. Coarse-ground grains and access to litter have also been shown to decrease Salmonella shedding in poultry. The feed can also modify the gastro-intestinal tract microflora and influence the immune system, which can minimize Salmonella colonization and shedding. Feed additives, such as organic acids, short- and medium-chain fatty acids, probiotics, including competitive exclusion cultures, prebiotics and certain specific carbohydrates, such as mannan-based compounds, egg proteins, essential oils

Samsung Salmonella Detection Kit. AOAC Performance Tested Method(SM) 021203.

PubMed

Li, Jun; Cheung, Win Den; Opdyke, Jason; Harvey, John; Chong, Songchun; Moon, Cheol Gon

2012-01-01

Salmonella, one of the most common causes of foodborne illness, is a significant public health concern worldwide. There is a need in the food industry for methods that are simple, rapid, and sensitive for the detection of foodborne pathogens. In this study, the Samsung Salmonella Detection Kit, a real-time PCR assay for the detection of Salmonella, was evaluated according to the current AOAC guidelines. The validation consisted of lot-to-lot consistency, stability, robustness, and inclusivity/exclusivity studies, as well as a method comparison of 10 different food matrixes. In the validation, the Samsung Salmonella Detection Kit was used in conjunction with the Applied Biosystems StepOnePlus PCR system and the Samsung Food Testing Software for the detection of Salmonella species. The performance of the assays was compared to the U.S. Department of Agriculture/Food Safety and Inspection Service-Microbiology Laboratory Guidebook (USDA/FSIS-MLG) 4.05: Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, and Catfish and the and U.S. Food and Drug Administration/Bacteriological Analytical Manual (FDA/BAM) Chapter 5 Salmonella reference methods. The validation was conducted using an unpaired study design for detection of Salmonella spp. in raw ground beef, raw pork, raw ground pork, raw chicken wings, raw salmon, alfalfa sprouts, pasteurized orange juice, peanut butter, pasteurized whole milk, and shell eggs. The Samsung Salmonella Detection Kit demonstrated lot-to-lot consistency among three independent lots as well as ruggedness with minor modifications to changes in enrichment incubation time, enrichment incubation temperature, and DNA sample volume for PCR reaction. Stability was observed for 13 months at -20 degrees C and 3 months at 5 degrees C. For the inclusivity/exclusivity study, the Samsung Salmonella Detection Kit correctly identified 147 Salmonella species isolates out of 147 isolates tested from each of three different enrichment

Salmonella contamination risk points in broiler carcasses during slaughter line processing.

PubMed

Rivera-Pérez, Walter; Barquero-Calvo, Elías; Zamora-Sanabria, Rebeca

2014-12-01

Salmonella is one of the foodborne pathogens most commonly associated with poultry products. The aim of this work was to identify and analyze key sampling points creating risk of Salmonella contamination in a chicken processing plant in Costa Rica and perform a salmonellosis risk analysis. Accordingly, the following examinations were performed: (i) qualitative testing (presence or absence of Salmonella), (ii) quantitative testing (Salmonella CFU counts), and (iii) salmonellosis risk analysis, assuming consumption of contaminated meat from the processing plant selected. Salmonella was isolated in 26% of the carcasses selected, indicating 60% positive in the flocks sampled. The highest Salmonella counts were observed after bleeding (6.1 log CFU per carcass), followed by a gradual decrease during the subsequent control steps. An increase in the percentage of contamination (10 to 40%) was observed during evisceration and spray washing (after evisceration), with Salmonella counts increasing from 3.9 to 5.1 log CFU per carcass. According to the prevalence of Salmonella -contaminated carcasses released to trade (20%), we estimated a risk of 272 cases of salmonellosis per year as a result of the consumption of contaminated chicken. Our study suggests that the processes of evisceration and spray washing represent a risk of Salmonella cross-contamination and/ or recontamination in broilers during slaughter line processing.

MALDI-TOF mass spectrometry provides high accuracy in identification of Salmonella at species level but is limited to type or subtype Salmonella serovars.

PubMed

Kang, Lin; Li, Nan; Li, Ping; Zhou, Yang; Gao, Shan; Gao, Hongwei; Xin, Wenwen; Wang, Jinglin

2017-04-01

Salmonella can cause global foodborne illnesses in humans and many animals. The current diagnostic gold standard used for detecting Salmonella infection is microbiological culture followed by serological confirmation tests. However, these methods are complicated and time-consuming. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis offers some advantages in rapid identification, for example, simple and fast sample preparation, fast and automated measurement, and robust and reliable identification up to genus and species levels, possibly even to the strain level. In this study, we established a reference database for species identification using whole-cell MALDI-TOF MS; the database consisted of 12 obtained main spectra of the Salmonella culture collection strains belonged to seven serotypes. Eighty-two clinical isolates of Salmonella were identified using established database, and partial 16S rDNA gene sequencing and serological method were used as comparison. We found that MALDI-TOF mass spectrometry provided high accuracy in identification of Salmonella at species level but was limited to type or subtype Salmonella serovars. We also tried to find serovar-specific biomarkers and failed. Our study demonstrated that (a) MALDI-TOF MS was suitable for identification of Salmonella at species level with high accuracy and (b) that MALDI-TOF MS method presented in this study was not useful for serovar assignment of Salmonella currently, because of its low matching with serological method and (c) MALDI-TOF MS method presented in this study was not suitable to subtype S. typhimurium because of its low discriminatory ability.

A Novel Chromogenic Ester Agar Medium for Detection of Salmonellae

PubMed Central

Cooke, Venitia M.; Miles, R. J.; Price, R. G.; Richardson, A. C.

1999-01-01

A novel agar medium, chromogenic Salmonella esterase (CSE) agar, for the differentiation of salmonellae is described. The agar contains peptones and nutrient extracts together with the following (grams per liter unless otherwise specified): 4-[2-(4-octanoyloxy-3,5-dimethoxyphenyl)-vinyl]-quinolinium-1-(propan-3-yl carboxylic acid) bromide (SLPA-octanoate; bromide form), 0.3223; lactose, 14.65; trisodium citrate dihydrate, 0.5; Tween 20, 3.0; ethyl 4-dimethylaminobenzoate, 0.035% (wt/vol), novobiocin, 70 mg liter−1. The key component of the medium is SLPA-octanoate, a newly synthesized ester formed from a C8 fatty acid and a phenolic chromophore. In CSE agar, the ester is hydrolyzed by Salmonella spp. to yield a brightly colored phenol which remains tightly bound within colonies. After 24 h of incubation at 37 or 42°C, colonies of typical Salmonella spp. were burgundy colored on a transparent yellow background, whereas non-Salmonella spp. were white, cream, yellow or transparent. CSE agar was evaluated by using a panel of strains including a high proportion of Salmonella and non-Salmonella strains giving atypical reactions on other differential agars. The sensitivity (93.1%) of CSE agar for non-typhi salmonellae compared favorably with those of Rambach (82.8%), xylose-lysine-deoxycholate (XLD; 91.4%), Hektoen-enteric (89.7%), and SM ID (91.4%) agars. The specificity (93.9%) was also comparable to those of other Salmonella media (SM ID agar, 95.9%; Rambach agar, 91.8%; XLD agar, 91.8%; Hektoen-enteric agar, 87.8%). Strains of Citrobacter freundii and Proteus spp. giving false-positive reactions with other media gave a negative color reaction on CSE agar. CSE agar enabled the detection of >30 Salmonella serotypes, including agona, anatum, enteritidis, hadar, heidelberg, infantis, montevideo, thompson, typhimurium, and virchow, which accounted for 91.8% of the salmonella isolates recorded by the Public Health Laboratory Service (Colindale, London, England) for 1997

Cross contamination of turkey carcasses by Salmonella species during defeathering.

PubMed

Nde, C W; McEvoy, J M; Sherwood, J S; Logue, C M

2007-01-01

Salmonella present on the feathers of live birds could be a source of contamination to carcass skin during defeathering. In this study, the possibility of transfer of Salmonella from the feathers of live turkeys to carcass tissue during the defeathering process at a commercial turkey processing plant was investigated. The contribution of scald water and the fingers of the picker machines to cross contamination were also examined. Over 4 visits, swab samples were collected from 174 randomly selected tagged birds before and after defeathering. Two swab samples from the fingers of the picker machines and a sample of scald water were also collected during each visit. Detection of Salmonella was carried out following standard cultural and identification methods. The DNA fingerprints obtained from pulsed field gel electrophoresis of Salmonella serotypes isolated before and after defeathering, from scald water, and from the fingers of the picker machines were compared to trace cross contamination routes. Salmonella prevalence was similar before and after defeathering during visits 2 and 3 and significantly increased after defeathering during visits 1 and 4. Over the 4 visits, all Salmonella subtypes obtained after defeathering were also isolated before defeathering. The results of this study suggest that Salmonella was transferred from the feathers to carcass skin during each visit. On each visit, the Salmonella subtypes isolated from the fingers of the picker machines were similar to subtypes isolated before and after defeathering, indicating that the fingers facilitate carcass cross contamination during defeathering. Salmonella isolated from scald water during visit 4 was related to isolates obtained before and after defeathering, suggesting that scald water is also a vehicle for cross contamination during defeathering. By using molecular subtyping, this study demonstrated the relationship between Salmonella present on the feathers of live turkeys and carcass skin after

Case report of Salmonella cross-contamination in a food laboratory.

PubMed

Rasschaert, Geertrui; De Reu, K; Heyndrickx, M; Herman, L

2016-03-10

This paper describes a case of Salmonella cross-contamination in a food laboratory. In 2012, chocolate bars shipped from Belgium to the USA were prevented from entering the USA because a Salmonella Rissen strain had been isolated from one of the chocolate bars in a Belgian food laboratory. However, a retrospective study of the Salmonella isolates sent from the laboratory to the Belgian National Reference Laboratory for Salmonella revealed that 7 weeks prior, a Salmonella Rissen strain has been isolated from fish meal in the same food laboratory. The chocolate bars were not expected to be contaminated with Salmonella because the ingredients all tested negative during the production process. Furthermore, because Salmonella Rissen is only rarely isolated from food, it was hypothesized that the two Salmonella Rissen isolates belonged to the same strain and that the second isolation event in this laboratory was caused by cross-contamination. To confirm this hypothesis, both Salmonella Rissen isolates were fingerprinted using different molecular techniques. To evaluate the discriminatory power of the techniques used, 11 other Salmonella Rissen isolates from different origins were included in the comparison. Pulsed-field gel electrophoresis, repetitive element palindromic PCR and three random amplified polymorphic DNA PCR assays were used. Repetitive element palindromic PCR and random amplified polymorphic DNA PCR assays were insufficiently discriminatory, whereas pulsed-field gel electrophoresis using the combination of two restriction enzymes showed sufficient discrimination to confirm the hypothesis. Although cross-contamination in food laboratories are rarely reported, cross-contamination can always occur. Laboratories should therefore always be aware of the possibility of cross-contamination, especially when enrichment is used in the microbiological analysis. Furthermore, it is advised that results showing isolates of the same serotype isolated in a short time frame

Fate of Salmonella throughout Production and Refrigerated Storage of Tahini.

PubMed

Zhang, Yangjunna; Keller, Susanne E; Grasso-Kelley, Elizabeth M

2017-06-01

Tahini, a low-moisture food that is made from sesame seeds, has been implicated in outbreaks of salmonellosis. In this study, the fate of Salmonella was determined through an entire process for the manufacture of tahini, including a 24-h seed soaking period before roasting, subsequent grinding, and storage at refrigeration temperature. Salmonella populations increased by more than 3 log CFU/g during a 24-h soaking period, reaching more than 7 log CFU/g. Survival of Salmonella during roasting at three temperatures, 95, 110, and 130°C, was assessed using seeds on which Salmonella was grown. Salmonella survival was impacted both by temperature and the water activity (a w ) at the beginning of the roasting period. When roasted at 130°C with a high initial a w (≥0.90) and starting Salmonella populations of ∼8.5 log CFU/g, populations quickly decreased below detection limits within the first 10 min. However, when the seeds were reduced to an a w of 0.45 before roasting at the same temperature, 3.5 log CFU/g remained on the seeds after 60 min. In subsequent storage studies, seeds were roasted at 130°C for 15 min before processing into tahini. For the storage studies, tahini was inoculated using two methods. The first method used seeds on which Salmonella was first grown before roasting. In the second method, Salmonella was inoculated into the tahini after manufacture. All tahini was stored for 119 days at 4°C. No change in Salmonella populations was recorded for tahini throughout the entire 119 days regardless of the inoculation method used. These combined results indicate the critical importance of a w during a roasting step during tahini manufacture. Salmonella that survive roasting will likely remain viable throughout the normal shelf life of tahini.

Evaluation of the broad-spectrum lytic capability of bacteriophage cocktails against various Salmonella serovars and their effects on weaned pigs infected with Salmonella Typhimurium.

PubMed

Seo, Byoung-Joo; Song, Eu-Tteum; Lee, Kichan; Kim, Jong-Won; Jeong, Chang-Gi; Moon, Sung-Hyun; Son, Jee Soo; Kang, Sang Hyeon; Cho, Ho-Seong; Jung, Byeong Yeal; Kim, Won-Il

2018-06-06

The broad-spectrum lytic capability of Salmonella bacteriophages against various Salmonella species was evaluated to determine their potential as an alternative for antibiotics, and the safety and preventive effects of the bacteriophages were assessed on mice and pigs. Four bacteriophage cocktails were prepared using 13 bacteriophages, and the lytic capability of the four bacteriophage cocktails was tested using Salmonella reference strains and field isolates. Bacteriophage cocktail C (SEP-1, SGP-1, STP-1, SS3eP-1, STP-2, SChP-1, SAP-1, SAP-2; ≥10 9 pfu/ml) showed the best lytic activity against the Salmonella reference strains (100% of 34) and field isolates (92.5% of 107). Fifty mice were then orally inoculated with bacteriophage cocktail C to determine the distribution of bacteriophages in various organs, blood and feces. The effects of bacteriophages on Salmonella infection in weaned pigs (n=15) were also evaluated through an experimental challenge with Salmonella Typhimurium after treatment with bacteriophage cocktail C. All mice exhibited distribution of the bacteriophages in all organs, blood and feces until 15 days post infection (dpi). After 35 dpi, bacteriophages were not detected in any of these specimens. As demonstrated in a pig challenge study, treatment with bacteriophage cocktail C reduced the level of Salmonella shedding in feces. The metagenomic analyses of these pig feces also revealed that bacteriophage treatment decreased the number of species of the Enterobacteriaceae family without significant disturbance to the normal fecal flora. This study showed that bacteriophages effectively controlled Salmonella in a pig challenge model and could be a good alternative for antibiotics to control Salmonella infection.

Biofilm Formation and Morphotypes of Salmonella enterica subsp.arizonae Differs from Those of Other Salmonella enterica Subspecies in Isolates from Poultry Houses.

PubMed

Lamas, A; Fernandez-No, I C; Miranda, J M; Vázquez, B; Cepeda, A; Franco, C M

2016-07-01

Salmonella serovars are responsible for foodborne diseases around the world. The ability to form biofilms allows microorganisms to survive in the environment. In this study, 73 Salmonella strains, belonging to four different subspecies, were isolated from poultry houses and foodstuffs and tested. Biofilm formation was measured at four different temperatures and two nutrient concentrations. Morphotypes and cellulose production were evaluated at three different temperatures. The presence of several genes related to biofilm production was also examined. All strains and subspecies of Salmonella had the ability to form biofilms, and 46.57% of strains produced biofilms under all conditions tested. Biofilm formation was strain dependent and varied according to the conditions. This is the first study to analyze biofilm formation in a wide number of Salmonella enterica subsp. arizonae strains, and no direct relationship between the high prevalence of Salmonella enterica subsp. arizonae strains and their ability to form biofilm was established. Morphotypes and cellulose production varied as the temperature changed, with 20°C being the optimum temperature for expression of the red, dry, and rough morphotype and cellulose. Salmonella enterica subsp. arizonae, whose morphotype is poorly studied, only showed a smooth and white morphotype and lacked the csgD and gcpA genes that are implicated in biofilm production. Thus, Salmonella biofilm formation under different environmental conditions is a public health problem because it can survive and advance through the food chain to reach the consumer.

Survey of Salmonella contamination in chicken layer farms in three Caribbean countries.

PubMed

Adesiyun, Abiodun; Webb, Lloyd; Musai, Lisa; Louison, Bowen; Joseph, George; Stewart-Johnson, Alva; Samlal, Sannandan; Rodrigo, Shelly

2014-09-01

This study was conducted to investigate the demography, management, and production practices on layer chicken farms in Trinidad and Tobago, Grenada, and St. Lucia and the frequency of risk factors for Salmonella infection. The frequency of isolation of Salmonella from the layer farm environment, eggs, feeds, hatchery, and imported day-old chicks was determined using standard methods. Of the eight risk factors (farm size, age group of layers, source of day-old chicks, vaccination, sanitation practices, biosecurity measures, presence of pests, and previous disease outbreaks) for Salmonella infection investigated, farm size was the only risk factor significantly associated (P = 0.031) with the prevalence of Salmonella; 77.8% of large farms were positive for this pathogen compared with 33.3 and 26.1% of medium and small farms, respectively. The overall isolation rate of Salmonella from 35 layer farms was 40.0%. Salmonella was isolated at a significantly higher rate (P < 0.05) from farm environments than from the cloacae. Only in Trinidad and Tobago did feeds (6.5% of samples) and pooled egg contents (12.5% of samples) yield Salmonella; however, all egg samples from hotels, hatcheries, and airports in this country were negative. Salmonella Anatum, Salmonella group C, and Salmonella Kentucky were the predominant serotypes in Trinidad and Tobago, Grenada, and St. Lucia, respectively. Although Salmonella infections were found in layer birds sampled, table eggs appear to pose minimal risk to consumers. However, the detection of Salmonella -contaminated farm environments and feeds cannot be ignored. Only 2.9% of the isolates belonged to Salmonella Enteritidis, a finding that may reflect the impact of changes in farm management and poultry production in the region.

From Exit to Entry: Long-term Survival and Transmission of Salmonella

PubMed Central

Waldner, Landon L.; MacKenzie, Keith D.; Köster,, Wolfgang; White, Aaron P.

2012-01-01

Salmonella spp. are a leading cause of human infectious disease worldwide and pose a serious health concern. While we have an improving understanding of pathogenesis and the host-pathogen interactions underlying the infection process, comparatively little is known about the survival of pathogenic Salmonella outside their hosts. This review focuses on three areas: (1) in vitro evidence that Salmonella spp. can survive for long periods of time under harsh conditions; (2) observations and conclusions about Salmonella persistence obtained from human outbreaks; and (3) new information revealed by genomic- and population-based studies of Salmonella and related enteric pathogens. We highlight the mechanisms of Salmonella persistence and transmission as an essential part of their lifecycle and a prerequisite for their evolutionary success as human pathogens. PMID:25436767

Evaluation of Molecular Methods for Identification of Salmonella Serovars

PubMed Central

Gurnik, Simone; Ahmad, Aaminah; Blimkie, Travis; Murphy, Stephanie A.; Kropinski, Andrew M.; Nash, John H. E.

2016-01-01

Classification by serotyping is the essential first step in the characterization of Salmonella isolates and is important for surveillance, source tracking, and outbreak detection. To improve detection and reduce the burden of salmonellosis, several rapid and high-throughput molecular Salmonella serotyping methods have been developed. The aim of this study was to compare three commercial kits, Salm SeroGen (Salm Sero-Genotyping AS-1 kit), Check&Trace (Check-Points), and xMAP (xMAP Salmonella serotyping assay), to the Salmonella genoserotyping array (SGSA) developed by our laboratory. They were assessed using a panel of 321 isolates that represent commonly reported serovars from human and nonhuman sources globally. The four methods correctly identified 73.8% to 94.7% of the isolates tested. The methods correctly identified 85% and 98% of the clinically important Salmonella serovars Enteritidis and Typhimurium, respectively. The methods correctly identified 75% to 100% of the nontyphoidal, broad host range Salmonella serovars, including Heidelberg, Hadar, Infantis, Kentucky, Montevideo, Newport, and Virchow. The sensitivity and specificity of Salmonella serovars Typhimurium and Enteritidis ranged from 85% to 100% and 99% to 100%, respectively. It is anticipated that whole-genome sequencing will replace serotyping in public health laboratories in the future. However, at present, it is approximately three times more expensive than molecular methods. Until consistent standards and methodologies are deployed for whole-genome sequencing, data analysis and interlaboratory comparability remain a challenge. The use of molecular serotyping will provide a valuable high-throughput alternative to traditional serotyping. This comprehensive analysis provides a detailed comparison of commercial kits available for the molecular serotyping of Salmonella. PMID:27194688

In vitro selection of RNA aptamer specific to Salmonella typhimurium.

PubMed

Han, Seung Ryul; Lee, Seong-Wook

2013-06-28

Salmonella is a major foodborne pathogen that causes a variety of human diseases. Development of ligands directly and specifically binding to the Salmonella will be crucial for the rapid detection of, and thus for efficient protection from, the virulent bacteria. In this study, we identified a RNA aptamer-based ligand that can specifically recognize Salmonella Typhimurium through SELEX technology. To this end, we isolated and characterized an RNase-resistant RNA aptamer that bound to the OmpC protein of Salmonella Typhimurium with high specificity and affinity (Kd ~ 20 nM). Of note, the selected aptamer was found to specifically bind to Salmonella Typhimurium, but neither to Gram-positive bacteria (Staphylococcus aureus) nor to other Gram-negative bacteria (Escherichia coli O157:H7). This was evinced by aptamer-immobilized ELISA and aptamer-linked precipitation experiments. This Salmonella species-specific aptamer could be useful as a diagnostic ligand against pathogen-caused foodborne sickness.

Administration of a Salmonella Enteritidis ΔhilAssrAfliG strain by coarse spray to newly hatched broilers reduces colonization and shedding of a Salmonella Enteritidis challenge strain.

PubMed

De Cort, W; Haesebrouck, F; Ducatelle, R; van Immerseel, F

2015-01-01

Consumption of contaminated poultry meat is still an important cause of Salmonella infections in humans. Colonization inhibition (CI) occurs when a live Salmonella strain is administered to chickens and subsequently protects against challenge with another Salmonella strain belonging to the same serotype. A Salmonella Enteritidis hilAssrAfliG deletion mutant has previously been proven to reduce colonization and shedding of a wild-type Salmonella Enteritidis strain in newly hatched broilers after experimental infection. In this study, we compared two administration routes for this strain. Administering the Salmonella Enteritidis ΔhilAssrAfliG strain through drinking water on the first day of life resulted in decreased fecal shedding and cecal colonization of a wild-type Salmonella Enteritidis challenge strain administered 24 h later using a seeder-bird model. When administering the CI strain by coarse spray on newly hatched broiler chicks, an even more pronounced reduction of cecal colonization was observed, and fecal shedding of the Salmonella Enteritidis challenge strain ceased during the course of the experiment. These data suggest that administering a Salmonella Enteritidis ΔhilAssrAfliG strain to newly hatched chicks using a coarse spray is a useful and effective method that reduces colonization and shedding of a wild-type Salmonella Enteritidis strain after early challenge. © 2014 Poultry Science Association Inc.

Prevalence and antimicrobial susceptibility of salmonellae isolates from reptiles in Taiwan.

PubMed

Chen, Chun-Yu; Chen, Wan-Ching; Chin, Shih-Chien; Lai, Yen-Hsueh; Tung, Kwong-Chung; Chiou, Chien-Shun; Hsu, Yuan-Man; Chang, Chao-Chin

2010-01-01

Pets, including reptiles, have been shown to be a source of Salmonella infection in humans. Due to increasing popularity and variety of exotic reptiles as pets in recent years, more human clinical cases of reptile-associated Salmonella infection have been identified. However, limited information is available with regard to serotypes in different reptiles (turtles, snakes, and lizards) and antimicrobial resistance of Salmonella in pet reptiles. The current study was thus conducted to determine the prevalence of Salmonella colonization in pet reptiles. Salmonella organisms were isolated from 30.9% of 476 reptiles investigated. The isolation prevalences were 69.7% (23/33), 62.8% (27/43), and 24.3% (97/400) in snakes, lizards, and turtles, respectively. A total of 44 different Salmonella serovars were identified. Compared with S. Heron, Bredeney, Treforest, and 4,[5],12:i:-, S. Typhimurium isolates were resistant to many antimicrobials tested, and notably 61.1% of the isolates were resistant to cephalothin. The results indicated that raising reptiles as pets could be a possible source of Salmonella infection in humans, particularly zoonotic Salmonella serovars such as S. Typhimurium that may be resistant to antimicrobials.

Survival and Filamentation of Salmonella enterica Serovar Enteritidis PT4 and Salmonella enterica Serovar Typhimurium DT104 at Low Water Activity

PubMed Central

Mattick, K. L.; Jørgensen, F.; Legan, J. D.; Cole, M. B.; Porter, J.; Lappin-Scott, H. M.; Humphrey, T. J.

2000-01-01

In this study we investigated the long-term survival of and morphological changes in Salmonella strains at low water activity (aw). Salmonella enterica serovar Enteritidis PT4 and Salmonella enterica serovar Typhimurium DT104 survived at low aw for long periods, but minimum humectant concentrations of 8% NaCl (aw, 0.95), 96% sucrose (aw, 0.94), and 32% glycerol (aw, 0.92) were bactericidal under most conditions. Salmonella rpoS mutants were usually more sensitive to bactericidal levels of NaCl, sucrose, and glycerol. At a lethal aw, incubation at 37°C resulted in more rapid loss of viability than incubation at 21°C. At aw values of 0.93 to 0.98, strains of S. enterica serovar Enteritidis and S. enterica serovar Typhimurium formed filaments, some of which were at least 200 μm long. Filamentation was independent of rpoS expression. When the preparations were returned to high-aw conditions, the filaments formed septa, and division was complete within approximately 2 to 3 h. The variable survival of Salmonella strains at low aw highlights the importance of strain choice when researchers produce modelling data to simulate worst-case scenarios or conduct risk assessments based on laboratory data. The continued increase in Salmonella biomass at low aw (without a concomitant increase in microbial count) would not have been detected by traditional microbiological enumeration tests if the tests had been performed immediately after low-aw storage. If Salmonella strains form filaments in food products that have low aw values (0.92 to 0.98), there are significant implications for public health and for designing methods for microbiological monitoring. PMID:10742199

Maternal vaccination as a Salmonella Typhimurium reduction strategy on pig farms.

PubMed

Smith, R P; Andres, V; Martelli, F; Gosling, B; Marco-Jimenez, F; Vaughan, K; Tchorzewska, M; Davies, R

2018-01-01

The control of Salmonella in pig production is necessary for public and animal health, and vaccination was evaluated as a strategy to decrease pig prevalence. The study examined the efficacy of a live Salmonella Typhimurium vaccine, administered to sows on eight commercial farrow-to-finish herds experiencing clinical salmonellosis or Salmonella carriage associated with S. Typhimurium or its monophasic variants. Results of longitudinal Salmonella sampling were compared against eight similarly selected and studied control farms. At the last visit (~14 months after the start of vaccination), when all finishing stock had been born to vaccinated sows, both faecal shedding and environmental prevalence of Salmonella substantially declined on the majority of vaccinated farms in comparison to the controls. A higher proportion of vaccine farms resolved clinical salmonellosis than controls. However, Salmonella counts in positive faeces samples were similar between nonvaccinated and vaccinated herds. The results suggest that maternal vaccination is a suitable option for a Salmonella Typhimurium reduction strategy in farrow-to-finish pig herds. Salmonella vaccines have the potential to reduce the prevalence of Salmonella in pigs and result in a reduction of human cases attributed to pork. © 2017 Crown copyright. Journal of Applied Microbiology © 2017 The Society for Applied Microbiology. This article is published with the permission of the Controller of HMSO and the Queen’s Printer for Scotland.

Prophylactic administration of vector-encoded porcine granulocyte-colony stimulating factor reduces Salmonella shedding,tonsil colonization,& microbiota alterations of the gastrointestinal tract in Salmonella-challenged swine

USDA-ARS?s Scientific Manuscript database

Salmonella colonization of food animals is a concern for animal health and public health as a food safety risk. Various obstacles impede the effort to reduce asymptomatic Salmonella carriage in food animals, including the existence of numerous serovars and the ubiquitous nature of Salmonella. To d...

[A quantitative risk assessment model of salmonella on carcass in poultry slaughterhouse].

PubMed

Zhang, Yu; Chen, Yuzhen; Hu, Chunguang; Zhang, Huaning; Bi, Zhenwang; Bi, Zhenqiang

2015-05-01

To construct a quantitative risk assessment model of salmonella on carcass in poultry slaughterhouse and to find out effective interventions to reduce salmonella contamination. We constructed a modular process risk model (MPRM) from evisceration to chilling in Excel Sheet using the data of the process parameters in poultry and the Salmomella concentration surveillance of Jinan in 2012. The MPRM was simulated by @ risk software. The concentration of salmonella on carcass after chilling was 1.96MPN/g which was calculated by model. The sensitive analysis indicated that the correlation coefficient of the concentration of salmonella after defeathering and in chilling pool were 0.84 and 0.34,which were the primary factors to the concentration of salmonella on carcass after chilling. The study provided a quantitative assessment model structure for salmonella on carcass in poultry slaughterhouse. The risk manager could control the contamination of salmonella on carcass after chilling by reducing the concentration of salmonella after defeathering and in chilling pool.

Rapid Determination of Salmonella in Samples of Egg Noodles, Cake Mixes, and Candies

PubMed Central

Banwart, George J.; Kreitzer, Madeleine J.

1969-01-01

A glass apparatus system was compared with a standard enrichment broth-selective agar method to test samples of egg noodles, cake mixes, and candy for the presence or absence of salmonellae. The glass apparatus system used fermentation of mannitol, production of H2S, or motility, in conjunction with a serological test of flagellar antigens, to detect salmonellae. No salmonellae were detected in 173 samples of food products. Of these samples, 171 were found to be Salmonella-negative after 48 hr with the glass apparatus system. After 72 hr, the standard Salmonella procedure yielded 38 samples which produced Salmonella false-positive results on selective agars. Inoculation of samples with cultures of Salmonella showed that approximately one inoculated cell could be detected after 48 hr of incubation with the glass apparatus. The standard Salmonella test requires a minimum of 72 hr for completion. Compared with the standard Salmonella test, the glass apparatus system is a more rapid and simple system that can be used to determine the presence or absence of Salmonella in these food products. Images PMID:5370460

Salmonella and eggs: from production to plate.

PubMed

Whiley, Harriet; Ross, Kirstin

2015-02-26

Salmonella contamination of eggs and egg shells has been identified as a public health concern worldwide. A recent shift in consumer preferences has impacted on the egg industry, with a push for cage-free egg production methods. There has also been an increased desire from consumers for raw and unprocessed foods, potentially increasing the risk of salmonellosis. In response to these changes, this review explores the current literature regarding Salmonella contamination of eggs during the production processing through to food handling protocols. The contamination of eggs with Salmonella during the production process is a complex issue, influenced by many variables including flock size, flock age, stress, feed, vaccination, and cleaning routines. Currently there is no consensus regarding the impact of caged, barn and free range egg production has on Salmonella contamination of eggs. The literature regarding the management and control strategies post-collection, during storage, transport and food handling is also reviewed. Pasteurisation and irradiation were identified as the only certain methods for controlling Salmonella and are essential for the protection of high risk groups, whereas control of temperature and pH were identified as potential control methods to minimise the risk for foods containing raw eggs; however, further research is required to provide more detailed control protocols and education programs to reduce the risk of salmonellosis from egg consumption.

Salmonella and Eggs: From Production to Plate

PubMed Central

Whiley, Harriet; Ross, Kirstin

2015-01-01

Salmonella contamination of eggs and egg shells has been identified as a public health concern worldwide. A recent shift in consumer preferences has impacted on the egg industry, with a push for cage-free egg production methods. There has also been an increased desire from consumers for raw and unprocessed foods, potentially increasing the risk of salmonellosis. In response to these changes, this review explores the current literature regarding Salmonella contamination of eggs during the production processing through to food handling protocols. The contamination of eggs with Salmonella during the production process is a complex issue, influenced by many variables including flock size, flock age, stress, feed, vaccination, and cleaning routines. Currently there is no consensus regarding the impact of caged, barn and free range egg production has on Salmonella contamination of eggs. The literature regarding the management and control strategies post-collection, during storage, transport and food handling is also reviewed. Pasteurisation and irradiation were identified as the only certain methods for controlling Salmonella and are essential for the protection of high risk groups, whereas control of temperature and pH were identified as potential control methods to minimise the risk for foods containing raw eggs; however, further research is required to provide more detailed control protocols and education programs to reduce the risk of salmonellosis from egg consumption. PMID:25730295

Survival potential of wild type cellulose deficient Salmonella from the feed industry.

PubMed

Vestby, Lene K; Møretrø, Trond; Ballance, Simon; Langsrud, Solveig; Nesse, Live L

2009-11-23

Biofilm has been shown to be one way for Salmonella to persist in the feed factory environment. Matrix components, such as fimbriae and cellulose, have been suggested to play an important role in the survival of Salmonella in the environment. Multicellular behaviour by Salmonella is often categorized according to colony morphology into rdar (red, dry and rough) expressing curli fimbriae and cellulose, bdar (brown, dry and rough) expressing curli fimbriae and pdar (pink, dry and rough) expressing cellulose. The aim of the study was to look into the distribution of morphotypes among feed and fish meal factory strains of Salmonella, with emphasis on potential differences between morphotypes with regards to survival in the feed factory environment. When screening a total of 148 Salmonella ser. Agona, Salmonella ser. Montevideo, Salmonella ser. Senftenberg and Salmonella ser. Typhimurium strains of feed factory, human clinical and reference collection origin, as many as 99% were able to express rough morphology (rdar or bdar). The dominant morphotype was rdar (74%), however as many as 55% of Salmonella ser. Agona and 19% of Salmonella ser. Senftenberg displayed the bdar morphology. Inconsistency in Calcofluor binding, indicating expression of cellulose, was found among 25% of all the strains tested, however Salmonella ser. Agona showed to be highly consistent in Calcofluor binding (98%). In biofilm, Salmonella ser. Agona strains with bdar mophology was found to be equally tolerant to disinfection treatment as strains with rdar morphotype. However, rdar morphology appeared to be favourable in long term survival in biofilm in a very dry environment. Chemical analysis showed no major differences in polysaccharide content between bdar and rdar strains. Our results indicate that cellulose is not a major component of the Salmonella biofilm matrix. The bdar morphotype is common among Salmonella ser. Agona strains isolated from the factory environment. The rdar and the bdar

Diversity of Antimicrobial Resistance Phenotypes in Salmonella Isolated from Commercial Poultry Farms.

PubMed

Liljebjelke, Karen A; Hofacre, Charles L; White, David G; Ayers, Sherry; Lee, Margie D; Maurer, John J

2017-01-01

Salmonella remains the leading cause of foodborne illness in the United States, and the dissemination of drug-resistant Salmonellae through the food chain has important implications for treatment failure of salmonellosis. We investigated the ecology of Salmonella in integrated broiler production in order to understand the flow of antibiotic susceptible and resistant strains within this system. Data were analyzed from a retrospective study focused on antimicrobial resistant Salmonella recovered from commercial broiler chicken farms conducted during the initial years of the US FDA's foray into retail meat surveillance by the National Antimicrobial Resistance Monitoring System (NARMS). Sixty-three percentage of Salmonella were pan-susceptible to a panel of 19 antimicrobials used by the NARMS program. Twenty-five antimicrobial resistance phenotypes were observed in Salmonella isolated from two broiler chicken farms. However, Salmonella displaying resistance to streptomycin, alone, and in combination with other antibiotics was the most prevalent (36.3%) antimicrobial resistance phenotype observed. Resistance to streptomycin and sulfadimethoxine appeared to be linked to the transposon, Tn 21 . Combinations of resistance against streptomycin, gentamicin, sulfadimethoxine, trimethoprim, and tetracycline were observed for a variety of Salmonella enterica serovars and genetic types as defined by pulsed-field gel electrophoresis. There were within and between farm differences in the antibiotic susceptibilities of Salmonella and some of these differences were linked to specific serovars. However, farm differences were not linked to antibiotic usage. Analysis of the temporal and spatial distribution of the endemic Salmonella serovars on these farms suggests that preventing vertical transmission of antibiotic-resistant Salmonella would reduce carcass contamination with antibiotic-resistant Salmonella and subsequently human risk exposure.

Diversity of Antimicrobial Resistance Phenotypes in Salmonella Isolated from Commercial Poultry Farms

PubMed Central

Liljebjelke, Karen A.; Hofacre, Charles L.; White, David G.; Ayers, Sherry; Lee, Margie D.; Maurer, John J.

2017-01-01

Salmonella remains the leading cause of foodborne illness in the United States, and the dissemination of drug-resistant Salmonellae through the food chain has important implications for treatment failure of salmonellosis. We investigated the ecology of Salmonella in integrated broiler production in order to understand the flow of antibiotic susceptible and resistant strains within this system. Data were analyzed from a retrospective study focused on antimicrobial resistant Salmonella recovered from commercial broiler chicken farms conducted during the initial years of the US FDA’s foray into retail meat surveillance by the National Antimicrobial Resistance Monitoring System (NARMS). Sixty-three percentage of Salmonella were pan-susceptible to a panel of 19 antimicrobials used by the NARMS program. Twenty-five antimicrobial resistance phenotypes were observed in Salmonella isolated from two broiler chicken farms. However, Salmonella displaying resistance to streptomycin, alone, and in combination with other antibiotics was the most prevalent (36.3%) antimicrobial resistance phenotype observed. Resistance to streptomycin and sulfadimethoxine appeared to be linked to the transposon, Tn21. Combinations of resistance against streptomycin, gentamicin, sulfadimethoxine, trimethoprim, and tetracycline were observed for a variety of Salmonella enterica serovars and genetic types as defined by pulsed-field gel electrophoresis. There were within and between farm differences in the antibiotic susceptibilities of Salmonella and some of these differences were linked to specific serovars. However, farm differences were not linked to antibiotic usage. Analysis of the temporal and spatial distribution of the endemic Salmonella serovars on these farms suggests that preventing vertical transmission of antibiotic-resistant Salmonella would reduce carcass contamination with antibiotic-resistant Salmonella and subsequently human risk exposure. PMID:28691011

The treatment of mouse colorectal cancer by oral delivery tumor-targeting Salmonella

PubMed Central

Wang, Wei-Kuang; Lu, Meng-Fan; Kuan, Yu-Diao; Lee, Che-Hsin

2015-01-01

Systemic administration of Salmonella to tumor-bearing mice leads to its preferential accumulation in tumor sites, the enhancement of host immunity, and the inhibition of tumor growth. However, the underlying mechanism for Salmonella-induced antitumor immune response via oral delivery remained uncertain. Herein, we used mouse colorectal cancer (CT26) as tumor model to study the therapeutic effects after oral delivery of Salmonella. When orally administered into tumor-bearing mice, Salmonella significantly accumulated in the tumor sites, inhibited tumor growth and extended the survival of mice. No obvious toxicity was observed during orally administered Salmonella by examining body weight and inflammatory cytokines. As indoleamine 2, 3-dioxygenase 1 (IDO) is a crucial mediator for tumor-mediated immune tolerance, we examined the expression of IDO. We demonstrated that Salmonella inhibited IDO expression in mouse cancer cells. Furthermore, immunohistochemical studies of the tumors revealed the infiltration of neutrophils and T cells in mice treated with Salmonella. In conclusion, our results indicate that Salmonella exerts its tumoricidal effects and stimulates T cell activities by inhibiting IDO expression. Oral delivery of Salmonella may, represent a potential strategy for the treatment of tumor. PMID:26328252

The OmpL porin does not modulate redox potential in the periplasmic space of Escherichia coli.

PubMed

Sardesai, Abhijit A; Genevaux, Pierre; Schwager, Françoise; Ang, Debbie; Georgopoulos, Costa

2003-04-01

The Escherichia coli DsbA protein is the major oxidative catalyst in the periplasm. Dartigalongue et al. (EMBO J., 19, 5980-5988, 2000) reported that null mutations in the ompL gene of E.coli fully suppress all phenotypes associated with dsbA mutants, i.e. sensitivity to the reducing agent dithiothreitol (DTT) and the antibiotic benzylpenicillin, lack of motility, reduced alkaline phosphatase activity and mucoidy. They showed that OmpL is a porin and hypothesized that ompL null mutations exert their suppressive effect by preventing efflux of a putative oxidizing-reducing compound into the medium. We have repeated these experiments using two different ompL null alleles in at least three different E.coli K-12 genetic backgrounds and have failed to reproduce any of the ompL suppressive effects noted above. Also, we show that, contrary to earlier results, ompL null mutations alone do not result in partial DTT sensitivity or partial motility, nor do they appreciably affect bacterial growth rates or block propagation of the male-specific bacteriophage M13. Thus, our findings clearly demonstrate that ompL plays no perceptible role in modulating redox potential in the periplasm of E.coli.

A Perspective on Invasive Salmonella Disease in Africa.

PubMed

Crump, John A; Heyderman, Robert S

2015-11-01

Salmonella enterica is a leading cause of community-acquired bloodstream infection in Africa. The contribution of typhoidal and nontyphoidal Salmonella serovars to invasive disease varies considerably in place and time, even within the same country. Nonetheless, many African countries are now thought to experience typhoid fever incidence >100 per 100,000 per year with approximately 1% of patients dying. Invasive nontyphoidal Salmonella (iNTS) disease was estimated to cause 3.4 million illnesses and 681 316 deaths in 2010, with the most disease in Africa. Antimicrobial drug resistance is a growing problem in S. enterica that threatens to further compromise patient outcomes. Reservoirs for nontyphoidal Salmonella and the predominant routes of transmission for typhoidal and nontyphoidal Salmonella are not well understood in Africa, hampering the design of evidence-based, non-vaccine- and vaccine-based prevention measures. It is difficult to distinguish clinically invasive Salmonella disease from febrile illnesses caused by other pathogens. Blood cultures are the mainstay of laboratory diagnosis, but lack sensitivity due to the low magnitude of bacteremia, do not produce results at point of care, and are not widely available in Africa. Serologic approaches to diagnosis remain inaccurate, and nucleic acid amplification tests are also compromised by low concentrations of bacteria. High-throughput whole-genome sequencing, together with a range of novel analytic pipelines, has provided new insights into the complex pattern of epidemiology, pathogenesis, and host adaptation. Concerted efforts are therefore needed to apply these new tools in the context of high-quality field surveillance to improve diagnosis, patient management, control, and prevention of invasive Salmonella infections in Africa. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Around the World in 1,475 Salmonella Geo-serotypes

PubMed Central

Le Hello, Simon; de Jong, Birgitta; Rolfhamre, Per; Faensen, Daniel; Weill, François-Xavier; Giesecke, Johan

2016-01-01

It’s easy to remember Salmonella serotypes names, isn’t it? Surely, this is because the naming system of Salmonella serotypes is by far the most scientist friendly. Traditionally, most Salmonella serotypes have been named after geographic locations. We decided to explore the geographic locations to which Salmonella serotypes refer and describe some unexpected twists in the naming scheme. We found that 93% (n = 1,475) of the 1,585 serotypes could be categorized as geo-serotypes; that is, the name refers to a geographic location. The 3 countries with the most geo-serotypes are Germany, the United Kingdom, and the United States. Other serotype names refer to the name of a person, animal, tribe, or food item or are a composite of symptoms and host. The Salmonella serotypes naming scheme has had a valuable effect on public health microbiology, and in the current era of fast development of whole-genome sequencing, it should remain a reference.

A Salmonella nanoparticle mimic overcomes multidrug resistance in tumours.

PubMed

Mercado-Lubo, Regino; Zhang, Yuanwei; Zhao, Liang; Rossi, Kyle; Wu, Xiang; Zou, Yekui; Castillo, Antonio; Leonard, Jack; Bortell, Rita; Greiner, Dale L; Shultz, Leonard D; Han, Gang; McCormick, Beth A

2016-07-25

Salmonella enterica serotype Typhimurium is a food-borne pathogen that also selectively grows in tumours and functionally decreases P-glycoprotein (P-gp), a multidrug resistance transporter. Here we report that the Salmonella type III secretion effector, SipA, is responsible for P-gp modulation through a pathway involving caspase-3. Mimicking the ability of Salmonella to reverse multidrug resistance, we constructed a gold nanoparticle system packaged with a SipA corona, and found this bacterial mimic not only accumulates in tumours but also reduces P-gp at a SipA dose significantly lower than free SipA. Moreover, the Salmonella nanoparticle mimic suppresses tumour growth with a concomitant reduction in P-gp when used with an existing chemotherapeutic drug (that is, doxorubicin). On the basis of our finding that the SipA Salmonella effector is fundamental for functionally decreasing P-gp, we engineered a nanoparticle mimic that both overcomes multidrug resistance in cancer cells and increases tumour sensitivity to conventional chemotherapeutics.

Serotype determination of Salmonella by xTAG assay.

PubMed

Zheng, Zhibei; Zheng, Wei; Wang, Haoqiu; Pan, Jincao; Pu, Xiaoying

2017-10-01

Currently, no protocols or commercial kits are available to determine the serotypes of Salmonella by using Luminex MAGPIX®. In this study, an xTAG assay for serotype determination of Salmonella suitable for Luminex MAGPIX® is described and 228 Salmonella isolates were serotype determined by this xTAG assay. The xTAG assay consists of two steps: 1) Multiplex PCR to amplify simultaneously O, H and Vi antigen genes of Salmonella, and 2) Magplex-TAG™ microsphere hybridization to identify accurately the specific PCR products of different antigens. Compared with the serotyping results of traditional serum agglutination test, the sensitivity and specificity of the xTAG assay were 95.1% and 100%, respectively. The agreement rate of these two assays was 95.2%. Compared with Luminex xMAP® Salmonella Serotyping Assay (SSA) kit, the advantages of this xTAG assay are: First, the magnetic beads make it applicable to both the Luminex®100/200™ and MAGPIX® systems. Second, only primers rather than both primers and probes are needed in the xTAG assay, and the process of coupling antigen-specific oligonucleotide probes to beads is circumvented, which make the xTAG assay convenient to be utilized by other laboratories. The xTAG assay may serve as a rapid alternative or complementary method for traditional Salmonella serotyping tests, especially for laboratories that utilize the MAGPIX® systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Salmonella-host cell interactions, changes in host cell architecture, and destruction of prostate tumor cells with genetically altered Salmonella.

PubMed

Zhong, Zhisheng; Kazmierczak, Robert A; Dino, Alison; Khreis, Rula; Eisenstark, Abraham; Schatten, Heide

2007-10-01

Increasingly, genetically modified Salmonella are being explored as a novel treatment for cancer because Salmonella preferentially replicate within tumors and destroy cancer cells without causing the septic shock that is typically associated with wild-type S. typhimurium infections. However, the mechanisms by which genetically modified Salmonella strains preferentially invade cancer cells have not yet been addressed in cellular detail. Here we present data that show S. typhimurium strains VNP20009, LT2, and CRC1674 invasion of PC-3M prostate cancer cells. S. typhimurium-infected PC-3M human prostate cancer cells were analyzed with immunofluorescence microscopy and transmission electron microscopy (TEM) at various times after inoculation. We analyzed microfilaments, microtubules, and DNA with fluorescence and immunofluorescence microscopy. 3T3 Phi-Yellow-mitochondria mouse 3T3 cells were used to study the effects of Salmonella infestation on mitochondria distribution in live cells. Our TEM results show gradual destruction of mitochondria within the PC-3M prostate cancer cells with complete loss of cristae at 8 h after inoculation. The fluorescence intensity in YFP-mitochondria-transfected mouse 3T3 cells decreased, which indicates loss of mitochondria structure. Interestingly, the nucleus does not appear affected by Salmonella within 8 h. Our data demonstrate that genetically modified S. typhimurium destroy PC-3M prostate cancer cells, perhaps by preferential destruction of mitochondria.

MicroSEQ® Salmonella spp. Detection Kit Using the Pathatrix® 10-Pooling Salmonella spp. Kit Linked Protocol Method Modification.

PubMed

Wall, Jason; Conrad, Rick; Latham, Kathy; Liu, Eric

2014-03-01

Real-time PCR methods for detecting foodborne pathogens offer the advantages of simplicity and quick time to results compared to traditional culture methods. The addition of a recirculating pooled immunomagnetic separation method prior to real-time PCR analysis increases processing output while reducing both cost and labor. This AOAC Research Institute method modification study validates the MicroSEQ® Salmonella spp. Detection Kit [AOAC Performance Tested Method (PTM) 031001] linked with the Pathatrix® 10-Pooling Salmonella spp. Kit (AOAC PTM 090203C) in diced tomatoes, chocolate, and deli ham. The Pathatrix 10-Pooling protocol represents a method modification of the enrichment portion of the MicroSEQ Salmonella spp. The results of the method modification were compared to standard cultural reference methods for diced tomatoes, chocolate, and deli ham. All three matrixes were analyzed in a paired study design. An additional set of chocolate test portions was analyzed using an alternative enrichment medium in an unpaired study design. For all matrixes tested, there were no statistically significant differences in the number of positive test portions detected by the modified candidate method compared to the appropriate reference method. The MicroSEQ Salmonella spp. protocol linked with the Pathatrix individual or 10-Pooling procedure demonstrated reliability as a rapid, simplified, method for the preparation of samples and subsequent detection of Salmonella in diced tomatoes, chocolate, and deli ham.

Global Screening of Salmonella enterica Serovar Typhimurium Genes for Desiccation Survival

PubMed Central

Mandal, Rabindra K.; Kwon, Young M.

2017-01-01

Salmonella spp., one of the most common foodborne bacterial pathogens, has the ability to survive under desiccation conditions in foods and food processing facilities for years. This raises the concerns of Salmonella infection in humans associated with low water activity foods. Salmonella responds to desiccation stress via complex pathways involving immediate physiological actions as well as coordinated genetic responses. However, the exact mechanisms of Salmonella to resist desiccation stress remain to be fully elucidated. In this study, we screened a genome-saturating transposon (Tn5) library of Salmonella Typhimurium (S. Typhimurium) 14028s under the in vitro desiccation stress using transposon sequencing (Tn-seq). We identified 61 genes and 6 intergenic regions required to overcome desiccation stress. Salmonella desiccation resistance genes were mostly related to energy production and conversion; cell wall/membrane/envelope biogenesis; inorganic ion transport and metabolism; regulation of biological process; DNA metabolic process; ABC transporters; and two component system. More than 20% of the Salmonella desiccation resistance genes encode either putative or hypothetical proteins. Phenotypic evaluation of 12 single gene knockout mutants showed 3 mutants (atpH, atpG, and corA) had significantly (p < 0.02) reduced survival as compared to the wild type during desiccation survival. Thus, our study provided new insights into the molecular mechanisms utilized by Salmonella for survival against desiccation stress. The findings might be further exploited to develop effective control strategies against Salmonella contamination in low water activity foods and food processing facilities. PMID:28943871

Prevalence of Salmonella spp. in pet turtles and their environment

PubMed Central

Back, Du-San; Shin, Gee-Wook; Wendt, Mitchell

2016-01-01

Pet turtles are known as a source of Salmonella infection to humans when handled in captivity. Thirty four turtles purchased from pet shops and online markets in Korea were examined to determine whether the turtles and their environment were contaminated with Salmonella spp. Salmonella spp. were isolated from fecal samples of 17 turtles. These isolates were identified as S. enterica through 16S rRNA gene sequencing. The isolation rate of Salmonella spp. from the soil and water samples increased over time. We concluded that a high percentage of turtles being sold in pet shops were infected with Salmonella spp., and their environments tend to become contaminated over time unless they are maintained properly. These results indicate that pet turtles could be a potential risk of salmonellosis in Korea. PMID:27729933

Turtles as a Possible Reservoir of Nontyphoidal Salmonella in Shanghai, China

PubMed Central

Zhang, Jianmin; Kuang, Dai; Wang, Fei; Meng, Jianghong; Jin, Huiming; Yang, Xiaowei; Liao, Ming; Klena, John D.; Wu, Shuyu; Zhang, Yongbiao; Xu, Xuebin

2017-01-01

Terrapins and turtles are known to transmit Salmonella to humans. However, little was known about the occurrence of this pathogen in soft-shelled terrapin that is a popular delicacy in Chinese and other East Asian cuisines. We isolated and characterized 82 (24.4%) isolates of Salmonella from 336 fecal samples of soft-shelled terrapins (51 of 172; 29.7%) and pet turtles (31 of 164; 18.9%) in Shanghai. Salmonella Thompson was the most common serotype (17.1%) among others. Many isolates (84.1%) were resistant to multiple antimicrobials (≥3). Molecular analysis of Salmonella Thompson and Salmonella Typhimurium using pulsed-field gel electrophoresis unveiled a close genetic relationship between several human and terrapin isolates. Our results highlight the risk associated with the handling and consumption of turtles and their role in the spread of Salmonella in the human salmonellosis. PMID:27267492

Salmonella rarely detected in Mississippi coastal waters and sediment.

PubMed

Carr, M R; Wang, S Y; McLean, T I; Flood, C J; Ellender, R D

2010-12-01

Standards for the rapid detection of individual pathogens from environmental samples have not been developed, but in their absence, the use of molecular-based detection methods coupled with traditional microbiology techniques allows for rapid and accurate pathogen detection from environmental waters and sediment. The aim of this research was to combine the use of enrichment with PCR for detection of Salmonella in Mississippi coastal waters and sediment and observe if that presence correlated with levels of enterococci and climatological variables. Salmonella were primarily found in samples that underwent nutrient enrichment and were present more frequently in freshwater than marine waters. Salmonella were detected infrequently in marine and freshwater sediments. There was a significant positive correlation between the presence of detectable Salmonella and the average enterococcal count. An inverse relationship, however, was observed between the frequency of detection and the levels of salinity, turbidity and sunlight exposure. Results from this study indicated the presence of Salmonella in Mississippi coastal waters, and sediments are very low with significant differences between freshwater and marine environments. Using pathogenic and novel nonpathogenic molecular markers, Salmonella do not appear to be a significant pathogenic genus along the Mississippi Coast. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

Development of a novel hexa-plex PCR method for identification and serotyping of Salmonella species.

PubMed

Li, Ruichao; Wang, Yang; Shen, Jianzhong; Wu, Congming

2014-01-01

Salmonella is one of the most important foodborne pathogens, which causes a huge economic burden worldwide. To detect Salmonella rapidly is very meaningful in preventing salmonellosis and decreasing economic losses. Currently, isolation of Salmonella is confirmed by biochemical and serobased serotyping methods, which are time consuming, labor intensive, and complicated. To solve this problem, a hexa-plex polymerase chain reaction (PCR) method was developed using comparative genomics analysis and multiplex PCR technology to detect Salmonella and Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Agona, Salmonella Choleraesuis, and Salmonella Pullorum simultaneously. The accuracy of this method was tested by a collection of 142 Salmonella. Furthermore, the strategy described in this article to mine serovar-specific fragments for Salmonella could be used to find specific fragments for other Salmonella serotypes and bacteria. The combination of this strategy and multiplex PCR is promising in the rapid identification of foodborne pathogens.

SURVIVAL OF SALMONELLA IN WASTE EGG WASH WATER

EPA Science Inventory

The survival of salmonellae under various environmental conditions has been subject of numerous research studies. Due to low densities of these organisms in natural samples, laboratory or clinical cultures were used to ensure that the initial density of salmonellae was sufficien...

A case-control study of domestic kitchen microbiology and sporadic Salmonella infection.

PubMed

Parry, S M; Slader, J; Humphrey, T; Holmes, B; Guildea, Z; Palmer, S R

2005-10-01

The microbiology of domestic kitchens in the homes of subjects who had suffered sporadic Salmonella infection (cases) was compared with control domestic kitchens. Case and control dishcloths and refrigerator swabs were examined for the presence of Salmonella spp., total Enterobacteriaceae counts and total aerobic colony counts. Salmonella spp. were isolated from both case and control dishcloths and refrigerators but there were no significant differences between the two groups. Colony counts were similar in case and control dishcloths and refrigerator swabs. There was no relationship between the total counts and presence of Salmonella . There was no evidence that cases of Salmonella infection were more likely to have kitchens which were contaminated with these bacteria or have higher bacterial counts than controls. Total bacterial counts were poor indicators of Salmonella contamination of the domestic kitchen environment. Further factors which could not be identified by a study of this design may increase risk of Salmonella food poisoning. These factors may include individual susceptibility of the patient. Alternatively, sporadic cases of Salmonella food poisoning may arise from food prepared outside the home.

Immunogenicity of Salmonella enterica serovar Enteritidis virulence protein, InvH, and cross-reactivity of its antisera with Salmonella strains.

PubMed

Dehghani, Behzad; Rasooli, Iraj; Gargari, Seyed Latif Mousavi; Nadooshan, Mohammad Reza Jalali; Owlia, Parviz; Nazarian, Shahram

2013-02-22

Acellular vaccines containing bacterial immunodominant components such as surface proteins may be potent alternatives to live attenuated vaccines in order to reduce salmonellosis risk to human health. invH gene, an important part of needle complex in type three secretion system (TTSS) plays important role in efficient bacterial adherence and entry into epithelial cells. In this work we hypothesize that use of a 15 kDa recombinant InvH as Salmonella enterica serovar Enteritidis surface protein could provoke antibody production in mouse and would help us study feasibility of its potential for diagnosis and/or a recombinant vaccine. The purified InvH provoked significant rise of IgG in mice. Active protection induced by immunization with InvH against variable doses of S. enterica serovar Enteritidis, indicated that the immunized mice were completely protected against challenge with 10(4) LD(50). The immunoreaction of sera from immunized mice with other Salmonella strains or cross reaction with sera of Salmonella strains inoculated mice is indicative of possessing by Salmonella strains of the surface protein, InvH, that can be employed in both prophylactic and diagnostic measures against S. enterica. Bacteria free spleen and ileum of the immunized mice in this study indicate that the invH gene affects bacterial invasion. Efficacy of the virulence protein, InvH, in shuttling into host cells in injectisome of S. enterica serovar Enteritidis and inhibition of this phenomenon by active immunization was shown in this study. In conclusion immunization with InvH protein can develop protection against S. enterica serovar Enteritidis infections. InvH in Salmonella strains can be exploited in protective measures as well as a diagnostic tool in Salmonella infections. Copyright © 2012 Elsevier GmbH. All rights reserved.

21 CFR 118.6 - Egg testing for Salmonella Enteritidis (SE).

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Egg testing for Salmonella Enteritidis (SE). 118.6... testing for Salmonella Enteritidis (SE). (a)(1) If the environmental test for pullets at 14 to 16 weeks of... requires that these eggs must be treated to achieve at least a 5-log destruction of Salmonella Enteritidis...

21 CFR 118.6 - Egg testing for Salmonella Enteritidis (SE).

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Egg testing for Salmonella Enteritidis (SE). 118.6... testing for Salmonella Enteritidis (SE). (a)(1) If the environmental test for pullets at 14 to 16 weeks of... requires that these eggs must be treated to achieve at least a 5-log destruction of Salmonella Enteritidis...

21 CFR 118.6 - Egg testing for Salmonella Enteritidis (SE).

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Egg testing for Salmonella Enteritidis (SE). 118.6... testing for Salmonella Enteritidis (SE). (a)(1) If the environmental test for pullets at 14 to 16 weeks of... requires that these eggs must be treated to achieve at least a 5-log destruction of Salmonella Enteritidis...

Dispersal of Salmonella Typhimurium by rain splash onto tomato plants.

PubMed

Cevallos-Cevallos, Juan M; Danyluk, Michelle D; Gu, Ganyu; Vallad, Gary E; van Bruggen, Ariena H C

2012-03-01

Outbreaks of Salmonella enterica have increasingly been associated with tomatoes and traced back to production areas, but the spread of Salmonella from a point source onto plants has not been described. Splash dispersal by rain could be one means of dissemination. Green fluorescent protein-labeled, kanamycin-resistant Salmonella enterica sv. Typhimurium dispensed on the surface of plastic mulch, organic mulch, or soil at 10⁸ CFU/cm² was used as the point source in the center of a rain simulator. Tomato plants in soil with and without plastic or organic mulch were placed around the point source, and rain intensities of 60 and 110 mm/h were applied for 5, 10, 20, and 30 min. Dispersal of Salmonella followed a negative exponential model with a half distance of 3 cm at 110 mm/h. Dispersed Salmonella survived for 3 days on tomato leaflets, with a total decline of 5 log and an initial decimal reduction time of 10 h. Recovery of dispersed Salmonella from plants at the maximum observed distance ranged from 3 CFU/g of leaflet after a rain episode of 110 mm/h for 10 min on soil to 117 CFU/g of leaflet on plastic mulch. Dispersal of Salmonella on plants with and without mulch was significantly enhanced by increasing rain duration from 0 to 10 min, but dispersal was reduced when rainfall duration increased from 10 to 30 min. Salmonella may be dispersed by rain to contaminate tomato plants in the field, especially during rain events of 10 min and when plastic mulch is used.

Relationship between aerobic bacteria, salmonellae and Campylobacter on broiler carcasses.

PubMed

Cason, J A; Bailey, J S; Stern, N J; Whittemore, A D; Cox, N A

1997-07-01

Broiler carcasses were removed from commercial processing lines immediately after defeathering, before chilling, and after chilling to determine whether any relationship exists between aerobic bacteria and the human enteropathogens salmonellae and Campylobacter. In two experiments, a whole carcass rinse procedure was used to sample 30 carcasses after defeathering, 90 carcasses before chilling, and 90 carcasses after chilling, for a total of 210 different carcasses. Aerobic bacteria and Campylobacter spp. were enumerated and the incidence of salmonellae was determined. Salmonellae and Campylobacter incidences were 20 and 94%, respectively, for all carcasses sampled. After picking, neither salmonellae-positive nor Campylobacter-positive carcasses had mean aerobic most probable number (MPN) values that were different from carcasses negative for those organisms. Immediately before chilling, aerobic and Campylobacter counts were 7.12 and 5.33 log10 cfu per carcass, respectively. Immersion chilling reduced aerobic counts by approximately 1.8 log and Campylobacter by 1.5 log, with no change in salmonellae-positive carcasses. There was no difference in aerobic or Campylobacter counts between carcasses that were positive or negative for salmonellae at any of the sampling locations, nor was any correlation found between levels of aerobic organisms and Campylobacter. Carcasses with aerobic counts above the mean or more than one standard deviation above the mean also failed to show any correlation. Discriminant analysis indicated error rates as high as 50% when numbers of aerobic bacteria were used to predict incidence of salmonellae or Campylobacter on individual carcasses. Aerobic bacteria are not suitable as index organisms for salmonellae or Campylobacter on broiler carcasses.

Observations on the distribution and control of Salmonella species in two integrated broiler companies.

PubMed

Davies, R; Breslin, M; Corry, J E; Hudson, W; Allen, V M

2001-08-25

The effectiveness of cleaning and disinfecting broiler farms and the persistence of Salmonella species in two integrated broiler companies was investigated for two years. Both companies used a cleaning and disinfection regime which included the application of a spray of phenolic disinfectant followed by fogging with formaldehyde solution, and this was highly effective in preventing carry-over of infection in the broiler houses. The disinfection of service areas and areas outside the houses was less effective but it had no influence on the Salmonella status of later flocks. Both companies had persistent problems with the contamination of pellet cooling systems in their feedmills with Salmonella 4, 12:d:- in company A, and with Salmonella binza and Salmonella ohio in company B. The hatcher incubators of both companies were also persistently contaminated with Salmonella livingstone and Salmonella thomasville in company A and with Salmonella senftenberg in company B. At both companies sites Salmonella enteritidis and Salmonella typhimurium Tr104 were also isolated occasionally from various locations.

One Health and Food-Borne Disease: Salmonella Transmission between Humans, Animals, and Plants.

PubMed

Silva, Claudia; Calva, Edmundo; Maloy, Stanley

2014-02-01

There are >2,600 recognized serovars of Salmonella enterica. Many of these Salmonella serovars have a broad host range and can infect a wide variety of animals, including mammals, birds, reptiles, amphibians, fish, and insects. In addition, Salmonella can grow in plants and can survive in protozoa, soil, and water. Hence, broad-host-range Salmonella can be transmitted via feces from wild animals, farm animals, and pets or by consumption of a wide variety of common foods: poultry, beef, pork, eggs, milk, fruit, vegetables, spices, and nuts. Broad-host-range Salmonella pathogens typically cause gastroenteritis in humans. Some Salmonella serovars have a more restricted host range that is associated with changes in the virulence plasmid pSV, accumulation of pseudogenes, and chromosome rearrangements. These changes in host-restricted Salmonella alter pathogen-host interactions such that host-restricted Salmonella organisms commonly cause systemic infections and are transmitted between host populations by asymptomatic carriers. The secondary consequences of efforts to eliminate host-restricted Salmonella serovars demonstrate that basic ecological principles govern the environmental niches occupied by these pathogens, making it impossible to thwart Salmonella infections without a clear understanding of the human, animal, and environmental reservoirs of these pathogens. Thus, transmission of S. enterica provides a compelling example of the One Health paradigm because reducing human infections will require the reduction of Salmonella in animals and limitation of transmission from the environment.

Specificity tests of an oligonucleotide probe against food-outbreak salmonella for biosensor detection

NASA Astrophysics Data System (ADS)

Chen, I.-H.; Horikawa, S.; Xi, J.; Wikle, H. C.; Barbaree, J. M.; Chin, B. A.

2017-05-01

Phage based magneto-elastic (ME) biosensors have been shown to be able to rapidly detect Salmonella in various food systems to serve food pathogen monitoring purposes. In this ME biosensor platform, the free-standing strip-shaped magneto-elastic sensor is the transducer and the phage probe that recognizes Salmonella in food serves as the bio-recognition element. According to Sorokulova et al. at 2005, a developed oligonucleotide probe E2 was reported to have high specificity to Salmonella enterica Typhimurium. In the report, the specificity tests were focused in most of Enterobacterace groups outside of Salmonella family. Here, to understand the specificity of phage E2 to different Salmonella enterica serotypes within Salmonella Family, we further tested the specificity of the phage probe to thirty-two Salmonella serotypes that were present in the major foodborne outbreaks during the past ten years (according to Centers for Disease Control and Prevention). The tests were conducted through an Enzyme linked Immunosorbent Assay (ELISA) format. This assay can mimic probe immobilized conditions on the magnetoelastic biosensor platform and also enable to study the binding specificity of oligonucleotide probes toward different Salmonella while avoiding phage/ sensor lot variations. Test results confirmed that this oligonucleotide probe E2 was high specific to Salmonella Typhimurium cells but showed cross reactivity to Salmonella Tennessee and four other serotypes among the thirty-two tested Salmonella serotypes.

Breast abscess in a man due to Salmonella enterica serotype Enteritidis.

PubMed

Brncic, Nada; Gorup, Lari; Strcic, Miroslav; Abram, Maja; Mustac, Elvira

2012-01-01

Nontyphoidal salmonellae can cause breast infection only exceptionally. A case of breast abscess in a 70-year-old man due to Salmonella enterica serotype Enteritidis (Salmonella Enteritidis) is reported. The infection was successfully treated with a combination of surgical and antibiotic treatment.

Plasmid-mediated quinolone resistance in non-Typhi serotypes of Salmonella enterica.

PubMed

Gay, Kathryn; Robicsek, Ari; Strahilevitz, Jacob; Park, Chi Hye; Jacoby, George; Barrett, Timothy J; Medalla, Felicita; Chiller, Tom M; Hooper, David C

2006-08-01

Serious infections with Salmonella species are often treated with fluoroquinolones or extended-spectrum beta-lactams. Increasingly recognized in Enterobacteriaceae, plasmid-mediated quinolone resistance is encoded by qnr genes. Here, we report the presence of qnr variants in human isolates of non-Typhi serotypes of Salmonella enterica (hereafter referred to as non-Typhi Salmonella) from the United States National Antimicrobial Resistance Monitoring System for Enteric Bacteria. All non-Typhi Salmonella specimens from the United States National Antimicrobial Resistance Monitoring System for Enteric Bacteria collected from 1996 to 2003 with ciprofloxacin minimum inhibitory concentrations > or = 0.06 microg/mL (233 specimens) and a subset with minimum inhibitory concentrations < or = 0.03 microg/mL (102 specimens) were screened for all known qnr genes (A, B, and S) by polymerase chain reaction. For isolates with positive results, qnr and quinolone resistance-determining region sequences were determined. Plasmids containing qnr genes were characterized by conjugation or transformation. Conjugative plasmids harboring qnrB variants were detected in 7 Salmonella enterica serotype Berta isolates and 1 Salmonella enterica serotype Mbandaka isolate. The S. Mbandaka plasmid also had an extended-spectrum beta -lactamase. Variants of qnrS on nonconjugative plasmids were detected in isolates of Salmonella enterica serotype Anatum and Salmonella enterica serotype Bovismorbificans. Plasmid-mediated quinolone resistance appears to be widely distributed, though it is still uncommon in non-Typhi Salmonella isolates from the United States, including strains that are quinolone susceptible by the criteria of the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards). The presence of this gene in non-Typhi Salmonella that causes infection in humans suggests potential for spread through the food supply, which is a public health

Effects of methyltestosterone on immunity against Salmonella Pullorum in dwarf chicks.

PubMed

Li, H; Zhang, Y; Zuo, S F; Lian, Z X; Li, N

2009-12-01

This study was conducted to determine effects of methyltestosterone on innate immunity and adaptive immunity against Salmonella Pullorum in dwarf chicks. In vivo experiment, comparisons of pathological sections, viable counts of bacteria, specific antibody levels, and subsets of T lymphocytes were set forth between chicks with or without 10(-7) M methyltestosterone treatment (2 d of age through 21 d of age) and challenged with 5 x 10(8) virulent Salmonella Pullorum (7 d of age), and in vitro experiment, phagocytic and killing abilities, reactive oxygen intermediate production, and reactive nitrogen intermediate production of monocytes-macrophages treated with high (10(-8) M/10(6) cell) or physiological (10(-14) M/10(6) cell) concentration of methyltestosterone were examined after Salmonella Pullorum infection. The results showed that (1) in vivo, administration of methyltestosterone enhanced susceptibility to Salmonella Pullorum infection and depressed cellular immunity against Salmonella Pullorum, whereas it had no effect on humoral immunity in dwarf chicks; (2) in vitro, at high concentration, methyltestosterone reduced (P < 0.05) monocytes-macrophages mediated reactive oxygen intermediate-dependent killing of Salmonella Pullorum, whereas low concentration of methyltestosterone enhanced (P < 0.05) reactive oxygen intermediate-dependent killing of Salmonella Pullorum in male dwarf chicks but not in females; and (3) although challenged with Salmonella Pullorum, phagocytic ability and monocytes-macrophages mediated reactive nitrogen intermediate-dependent killing were not affected by methyltestosterone in vitro. The results indicated that methyltestosterone affected the immune response to Salmonella Pullorum in dwarf chicks by changing monocytes-macrophages mediated reactive oxygen intermediate-dependent killing and cellular immunity, and the effects were dose-dependent; furthermore, the former 2 pathways played important roles in preventing Salmonella Pullorum

Occurrence of Campylobacter and Salmonella in ducks and duck eggs in Selangor, Malaysia.

PubMed

Nor Faiza, S; Saleha, A A; Jalila, A; Fauziah, N

2013-03-01

The importance of Campylobacter and Salmonella as foodborne pathogens is well recognised globally. A recent work in Penang found ducks in commercial farms were infected with these organisms. The aim of the study was to detect the presence of Campylobacter and Salmonella in ducks and Salmonella in duck eggs in farms in a small part of Selangor. Cloacal swabs were obtained from 75 ducks and 30 duck eggs from three farms. The isolation and identification of Campylobacter and Salmonella were done using conventional methods. Twelve percent of Campylobacter and 16.0% of Salmonella were isolated from the ducks sampled. Salmonella was absent on and in eggs. Campylobacter isolates consisted of 22% Campylobacter jejuni and the remaining was Campylobacter coli. Three Salmonella serovars identified were Salmonella Agona, S. Braenderup and S. Corvallis. The presence of Campylobacter and Salmonella in ducks may cause contamination of the meat during processing and handling which can constitute public health hazard. Moreover, the farm workers may be exposed to the organisms through contact with the infected animals.

Prevalence and concentration of Salmonella on raw shelled peanuts in the United States.

PubMed

Calhoun, Stephen; Post, Laurie; Warren, Benjamin; Thompson, Sterling; Bontempo, Ann Rogers

2013-04-01

Recalls and/or outbreaks associated with Salmonella contamination in peanut-containing products were reported over the past several years. There are very limited data available on the prevalence and concentration of Salmonella on raw shelled peanuts in the United States. The objectives of this study were to estimate the prevalence of Salmonella on raw shelled peanuts in the United States and to estimate that concentration of Salmonella. Samples of Runner- and Virginia-type raw shelled peanuts from the 2008, 2009, and 2010 crop years were proportionately sampled from each growing region, based on 2007 production volume. Of 944 raw shelled peanut samples (375 g each), 22 (2.33%) were positive for Salmonella by the VIDAS Salmonella assay. Salmonella serovars identified in this study included Agona, Anatum, Braenderup, Dessau, Hartford, Meleagridis, Muenchen, Rodepoort, Tennessee, and Tornow. The concentration levels of Salmonella in positive samples, as determined by a most-probable-number assay, were <0.03 to 2.4 MPN/g. These data will be useful when designing and validating processes for the reduction or elimination of Salmonella in peanuts and/or peanut-containing products.

Salmonella enterica isolated from wildlife at two Ohio rehabilitation centers.

PubMed

Jijón, Steffani; Wetzel, Amy; LeJeune, Jeffrey

2007-09-01

Between May and September 2004, fecal samples from various wildlife species admitted to two rehabilitation centers in Ohio were cultured for Salmonella enterica and Escherichia coli O157:H7. Eight of 71 (11%) samples, including specimens from three opossums (Didelphis virginiana), two gray squirrels (Sciurus carolinensis), a woodchuck (Marmota monax), a Harris hawk (Parabuteo unicinctus), and a screech owl (Otus asio) tested positive for Salmonella serovars Braenderup, Senftenberg, Oranienburg, and Kentucky. The Salmonella Oranienburg isolates were indistinguishable by pulsed-field gel electrophoresis. Most isolates were susceptible to commonly used antibiotics; however, the Salmonella Kentucky isolate was resistant to multiple beta-lactam antibiotics (amoxicillin/clavulanic acid and ampicillin), cefoxitin, and ceftiofur, a third-generation cephalosporin. Escherichia coli O157:H7 was not isolated from any sample. Transmission of Salmonella from wildlife may occur between animals at rehabilitation centers.

[Properties of Salmonella isolates in the Czech Republic].

PubMed

Srámová, H; Karpísková, R; Dĕdicová, D; Sisák, F; Rychlík, I

1999-08-01

Based on a grant project "Use and importance of epidemiological markers in Salmonella enteritidis and Salmonella typhimurium in the spread of salmonelloses in children under two years of age" implemented in 1995 to 1997, the authors investigated epidemiological markers in 1,186 salmonella isolates; the strains were isolated from faeces of 838 sick children, from 266 faeces of their contacts, from 49 specimens of incriminated foods and from 33 smears from the children's environment. Of 1,186 Salmonella isolates 999 were strains of S. enteritidis, 39 strains of S. typhimurium and 148 strains were not identified. The markers of Salmonella isolates were investigated from the aspect of biotyping--98% S. enteritidis were formed by the biovar Jena. 2% by biovar Essen; sensitivity to antibiotics--94.5% Salmonella strains were sensitive to 12 selected antibiotics, 2.9% were resistant and in 2.6% the resistance was in the intermediate zone; phagotyping--in 808 strains of S. enteritidis PT 8--88% predominated, in S. typhimurium DT 104 and DT 141; assessment of plasmid profiles--in strains of S. enteritidis plasmid 55 kb predominated, in three strains of S. typhimurium a plasmid size 95 kb; virulence--was compared in 43 strains isolated from hospitalized children with a severe clinical course with 39 strains from children treated at home. In vitro tests revealed that hospitalization of affected children was associated with virulence of the strains (SE phagotype 8) and not with age. The presented results are discussed with regard to the epidemiological situation in the Czech Republic and in the world.

Evaluation of two commercially available Salmonella vaccines on Salmonella concentration and prevalance in the peripheral lymph nodes of experimentally infected cattle

USDA-ARS?s Scientific Manuscript database

Bovine peripheral lymph nodes (PLN) may contain Salmonella, and unless contaminated nodes are removed during slaughter, they serve as a source of contamination for ground beef. Utilizing an experimental model of Salmonella inoculation of the PLN, two experiments were conducted to evaluate commercia...

Breast Abscess in a Man Due to Salmonella enterica Serotype Enteritidis

PubMed Central

Brnčić, Nada; Strčić, Miroslav; Abram, Maja; Mustač, Elvira

2012-01-01

Nontyphoidal salmonellae can cause breast infection only exceptionally. A case of breast abscess in a 70-year-old man due to Salmonella enterica serotype Enteritidis (Salmonella Enteritidis) is reported. The infection was successfully treated with a combination of surgical and antibiotic treatment. PMID:22031702

Limitations of a localized surface plasmon resonance sensor on Salmonella detection

USDA-ARS?s Scientific Manuscript database

We have designed a localized surface plasmon resonance (LSPR) biosensor to perform the whole cell detection of Salmonella using gold nanoparticls fabricated by oblique angle deposition technique. The LSPR sensor showed a plasmon peak shift due to the Salmonella antigen and anti-Salmonella antibody r...

Electron-beam-inactivated vaccine against Salmonella enteritidis colonization in molting hens

USDA-ARS?s Scientific Manuscript database

Electron Beam (eBeam) ionization technology has a variety of applications in modern society. The underlying hypothesis was that electron beam (eBeam) inactivated Salmonella enterica serovar Enteritidis (SE) cells can serve as a vaccine to control Salmonella colonization and Salmonella shedding in c...

Inactivation of Salmonella and Listeria in ground chicken breast meat during thermal processing.

PubMed

Murphy, R Y; Marks, B P; Johnson, E R; Johnson, M G

1999-09-01

Thermal inactivation of six Salmonella spp. and Listeria innocua was evaluated in ground chicken breast and liquid medium. Survival of Salmonella and Listeria was affected by the medium composition. Under the same thermal process condition, significantly more Salmonella and Listeria survived in chicken breast meat than in 0.1% peptone-agar solution. The thermal lethality of six tested Salmonella spp. was additive in chicken meat. Survival of Listeria in chicken meat during thermal processing was not affected by the presence of the six Salmonella spp. Sample size and shape affected the inactivation of Salmonella and Listeria in chicken meat during thermal processing.

Household Contamination with Salmonella enterica1

PubMed Central

Hancock, Dale D.; Roozen, Paivi M.; Szymanski, Maryanne H.; Scheenstra, Beth C.; Cady, Kirsten M.; Besser, Thomas E.; Chudek, Paul A.

2003-01-01

Household contamination with Salmonella enterica increases when occupational exposure exists (cattle farms with known salmonellosis in cattle, a salmonella research laboratory, or a veterinary clinic experiencing an outbreak of salmonellosis). Fifteen of 55 (27.2%) vacuum cleaner bags from households with occupational exposure to S. enterica were positive versus 1 of 24 (4.2% without known exposure. Use of a carpet cleaner and several cleaners/disinfectants reduced, but failed to eliminate, S. enterica from artificially contaminated carpet. PMID:12533294

Occurrence and characterization of Salmonella from chicken nuggets, strips, and pelleted broiler feed.

PubMed

Bucher, O; Holley, R A; Ahmed, R; Tabor, H; Nadon, C; Ng, L K; D'Aoust, J Y

2007-10-01

Raw, frozen chicken nuggets and strips have been identified as a significant risk factor in contracting foodborne salmonellosis. Cases of salmonellosis as a result of consuming partly cooked chicken nuggets may be due in part to Salmonella strains originating in broiler feed. This study was undertaken to determine the occurrence and characterize the strains of Salmonella contaminating chicken nuggets, strips, and pelleted feeds, in an attempt to demonstrate whether the same Salmonella strains present in broiler feed could be isolated from raw, frozen chicken nuggets and strips available for human consumption. Salmonellae were recovered using the Health Canada MFHPB-20 method for the isolation and identification of Salmonella from foods. Strains were characterized by serotyping, phage typing, antimicrobial resistance typing (R-typing), and by pulsed-field gel electrophoresis (PFGE). Salmonellae were isolated from 25-g samples in 27% (n=92) of nugget and strip samples, 95% (n=20) of chicken nugget meat samples, and from 9% (n=111) of pelleted feed samples. Salmonella Heidelberg, Salmonella Enteritidis, and Salmonella Orion were the most commonly isolated serovars from chicken nuggets and strips, nugget and strip meat, and pelleted broiler feeds, respectively. Salmonella Enteritidis phage type (PT) 13a with PFGE pattern SENXAI.0006 and R-type sensitive as well as Salmonella Enteritidis PT13a with PFGE pattern SENXAI.0068 and R-type sensitive were isolated from pelleted feed, and chicken nugget and strip meat in two separate instances. Data showed that Salmonella strains isolated from broiler feed were indistinguishable from strains isolated from packaged raw, frozen chicken nuggets and strips. However, results did not rule out the possibility that breeding stock or contamination during processing may have contributed to chicken meat contamination by Salmonella.

Salmonella epidemiology: A whirlwind of change.

PubMed

Besser, John M

2018-05-01

The field of infectious disease epidemiology for Salmonella and other enteric pathogens is undergoing some of the most profound changes since the time of Kauffman and White. Rapid advances in "big data" technologies such as genomics and metagenomics are making it possible to monitor and control salmonellosis in new and exciting ways. Epidemiological methods are becoming increasingly robust through the routine use of standardized hypothesis-generating questionnaires, iterative open-ended interviewing, informational trace-backs and new modeling techniques for describing the attribution of disease to food sources. In addition, Salmonella epidemiology is facing important challenges and new opportunities due to the rapid adoption of culture independent diagnostic test panels by clinical laboratories. Where is this unprecedented wave of change taking us? This chapter will examine emerging trends in Salmonella epidemiology, and take a peek into the not-so-distant future. Published by Elsevier Ltd.

Commercially laid eggs vs. discarded hatching eggs: contamination by Salmonella spp.

PubMed

Kottwitz, Luciana B M; Leão, Joice Aparecida; Back, Alberto; Rodrigues, Dalia dos P; Magnani, Marciane; de Oliveira, Tereza C R M

2013-01-01

Salmonella enterica is frequently associated with outbreaks of human salmonellosis, and products of avian origin, such as eggs and chicken meat, are the main vehicles of its transmission. The present study describes the occurrence of different serovars of Salmonella enterica and phagotypes of S. enterica serovar Enteritidis in eggs destined for human consumption. Four thousand eggs obtained from commercial egg laying farms and one thousand discarded hatching eggs from broiler farms, which were acquired at farmers' markets and informal shops, were analyzed. Salmonella spp. was isolated from 52.0% of the discarded hatching eggs, in which the predominant serovar was Enteritidis (84.6%), and the predominant Salmonella Enteritidis phagotype (PT) was PT7 (26.9%). Salmonella spp. was not isolated from eggs obtained from commercial egg laying farms. The antimicrobial resistance profile showed that 23.1% (n = 6) of the SE strains were resistant to nalidixic acid. The results suggest that the consumption of discarded hatching eggs represents an important source of Salmonella transmission to humans.

Prevalence of Salmonella on retail broiler chicken meat carcasses in Colombia.

PubMed

Donado-Godoy, Pilar; Clavijo, Viviana; León, Maribel; Tafur, Mc Allister; Gonzales, Sebastian; Hume, Michael; Alali, Walid; Walls, Isabel; Lo Fo Wong, Danilo M A; Doyle, M P

2012-06-01

A cross-sectional study was performed to estimate the prevalence of Salmonella on retail market chicken carcasses in Colombia. A total of 1,003 broiler chicken carcasses from 23 departments (one city per department) were collected via a stratified sampling method. Carcass rinses were tested for the presence of Salmonella by conventional culture methods. Salmonella strains were isolated from 27 % of the carcasses sampled. Logistic regression analysis was used to determine potential risk factors for Salmonella contamination associated with the chicken production system (conventional versus free-range), storage condition (chilled versus frozen), retail store type (supermarket, independent, and wet market), poultry company (integrated company versus nonintegrated company), and socioeconomic stratum. Chickens from a nonintegrated poultry company were associated with a significantly (P < 0.05) greater risk of Salmonella contamination (odds ratio, 2.0) than were chickens from an integrated company. Chilled chickens had a significantly (P < 0.05) higher risk of Salmonella contamination (odds ratio, 4.3) than did frozen chicken carcasses.

Inhibition of nalidixic acid-resistant salmonella on marinated chicken skin.

PubMed

Pathania, A; McKee, S R; Bilgili, S F; Singh, M

2010-11-01

Marination is widely used to enhance flavor and increase consumer acceptability of meat and poultry products. The impact of such marination on the safety and shelf life of poultry meat was evaluated in this study. A series of experiments were conducted to determine the efficacy of teriyaki and lemon pepper marinades against multiple strains of nalidixic acid (NAL)-resistant Salmonella. NAL-resistant Salmonella serovar (Typhimurium, Heidelberg, and Senftenberg) cultures were inoculated onto chicken skin at 0.6 to 3.14 log CFU/g in a 12-well titer plate. Inoculated chicken skin was exposed to teriyaki or lemon pepper marinades for up to 32 h and stored at 4 or 25°C to determine the prevalence of Salmonella. To determine Salmonella survival, a three-strain cocktail of Salmonella was inoculated at low (ca. 4 log CFU/g) and high (8 log CFU/g) levels onto chicken skin that was then marinated with either teriyaki or lemon pepper marinade for up to 32 h and stored at 4 or 25°C. Prevalence of Salmonella was significantly reduced (P ≤ 0.05) by teriyaki marinade at all levels of contamination regardless of storage temperature. Lemon pepper marinade reduced Salmonella prevalence (P ≤ 0.05) at low levels of contamination (10¹ and 10² CFU/g), whereas no significant effect (P > 0.05) was observed at higher levels of contamination. Marination of chicken skin with teriyaki marinade greatly reduced Salmonella prevalence and survival (P ≤ 0.05) regardless of the storage temperature, indicating the antimicrobial potential of this marinade for poultry and meat products.

Complete Genome Sequence of Salmonella enterica Serovar Typhimurium Strain YU15 (Sequence Type 19) Harboring the Salmonella Genomic Island 1 and Virulence Plasmid pSTV

PubMed Central

Calva, Edmundo; Puente, José L.; Zaidi, Mussaret B.

2016-01-01

The complete genome of Salmonella enterica subsp. enterica serovar Typhimurium sequence type 19 (ST19) strain YU15, isolated in Yucatán, Mexico, from a human baby stool culture, was determined using PacBio technology. The chromosome contains five intact prophages and the Salmonella genomic island 1 (SGI1). This strain carries the Salmonella virulence plasmid pSTV. PMID:27081132

21 CFR 866.3550 - Salmonella spp. serological reagents.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Salmonella spp. serological reagents. 866.3550 Section 866.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3550 Salmonella...

21 CFR 866.3550 - Salmonella spp. serological reagents.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Salmonella spp. serological reagents. 866.3550 Section 866.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3550 Salmonella...

21 CFR 866.3550 - Salmonella spp. serological reagents.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Salmonella spp. serological reagents. 866.3550 Section 866.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3550 Salmonella...

21 CFR 866.3550 - Salmonella spp. serological reagents.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Salmonella spp. serological reagents. 866.3550 Section 866.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3550 Salmonella...

21 CFR 866.3550 - Salmonella spp. serological reagents.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Salmonella spp. serological reagents. 866.3550 Section 866.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3550 Salmonella...

Orange peel products can reduce Salmonella populations in ruminants.

PubMed

Callaway, Todd R; Carroll, Jeffery A; Arthington, John D; Edrington, Tom S; Anderson, Robin C; Rossman, Michelle L; Carr, Mandy A; Genovese, Ken J; Ricke, Steve C; Crandall, Phil; Nisbet, David J

2011-10-01

Salmonella can live undetected in the gut of food animals and be transmitted to humans. Animal diets can impact intestinal populations of foodborne pathogens, including Salmonella spp. Orange juice production results in a waste product, orange peel and orange pulp, which has a high nutritive value and is often included in cattle diets as a least-cost ration ingredient. Here we show that the inclusion of orange peel products reduced Salmonella Typhimurium populations in the gut of experimentally inoculated sheep. Sheep (n=24) were fed a cracked corn grain-based high grain diet that was supplemented with a 50%/50% (dry matter [DM], w/w) mixture of dried orange pellet and fresh orange peel to achieve a final concentration (DM, basis) of 0%, 10%, or 20% orange product (OP) for 10 days before inoculation with Salmonella Typhimurium. Sheep were experimentally inoculated with 10(10) colony forming units Salmonella Typhimurium, and fecal samples were collected every 24 h after inoculation. Sheep were humanely euthanized at 96 h after oral Salmonella inoculation. Populations of inoculated Salmonella Typhimurium were numerically reduced by OP treatment throughout the gastrointestinal tract, and this reduction only reached significant levels in the cecum (p<0.05) of sheep fed 10% OP diets. Apparent palatability issues decreased the consumption of OP in sheep fed 20% OP to intake levels below that of 10% OP (approximately 7% dry matter intake [DMI]/d feed refusal), thereby reducing the potential effects of OP feeding at this higher level. Our results demonstrate that orange peel and pellets are environmentally friendly and low-cost products that can be used as a pre-harvest intervention as part of an integrated pathogen reduction scheme.

Genotypic and phenotypic characterization of multidrug resistant Salmonella Typhimurium and Salmonella Kentucky strains recovered from chicken carcasses

PubMed Central

Grant, Ar’Quette; Choi, Seon Young; Alam, M. Samiul; Bell, Rebecca; Cavanaugh, Christopher; Balan, Kannan V.; Babu, Uma S.

2017-01-01

Abstract Salmonella Typhimurium is the leading cause of human non-typhoidal gastroenteritis in the US. S. Kentucky is one the most commonly recovered serovars from commercially processed poultry carcasses. This study compared the genotypic and phenotypic properties of two Salmonella enterica strains Typhimurium (ST221_31B) and Kentucky (SK222_32B) recovered from commercially processed chicken carcasses using whole genome sequencing, phenotype characterizations and an intracellular killing assay. Illumina MiSeq platform was used for sequencing of two Salmonella genomes. Phylogenetic analysis employing homologous alignment of a 1,185 non-duplicated protein-coding gene in the Salmonella core genome demonstrated fully resolved bifurcating patterns with varying levels of diversity that separated ST221_31B and SK222_32B genomes into distinct monophyletic serovar clades. Single nucleotide polymorphism (SNP) analysis identified 2,432 (ST19) SNPs within 13 Typhimurium genomes including ST221_31B representing Sequence Type ST19 and 650 (ST152) SNPs were detected within 13 Kentucky genomes including SK222_32B representing Sequence Type ST152. In addition to serovar-specific conserved coding sequences, the genomes of ST221_31B and SK222_32B harbor several genomic regions with significant genetic differences. These included phage and phage-like elements, carbon utilization or transport operons, fimbriae operons, putative membrane associated protein-encoding genes, antibiotic resistance genes, siderophore operons, and numerous hypothetical protein-encoding genes. Phenotype microarray results demonstrated that ST221_31B is capable of utilizing certain carbon compounds more efficiently as compared to SK222_3B; namely, 1,2-propanediol, M-inositol, L-threonine, α-D-lactose, D-tagatose, adonitol, formic acid, acetoacetic acid, and L-tartaric acid. ST221_31B survived for 48 h in macrophages, while SK222_32B was mostly eliminated. Further, a 3-fold growth of ST221_31B was observed at

Genotypic and phenotypic characterization of multidrug resistant Salmonella Typhimurium and Salmonella Kentucky strains recovered from chicken carcasses.

PubMed

Tasmin, Rizwana; Hasan, Nur A; Grim, Christopher J; Grant, Ar'Quette; Choi, Seon Young; Alam, M Samiul; Bell, Rebecca; Cavanaugh, Christopher; Balan, Kannan V; Babu, Uma S; Parveen, Salina

2017-01-01

Salmonella Typhimurium is the leading cause of human non-typhoidal gastroenteritis in the US. S. Kentucky is one the most commonly recovered serovars from commercially processed poultry carcasses. This study compared the genotypic and phenotypic properties of two Salmonella enterica strains Typhimurium (ST221_31B) and Kentucky (SK222_32B) recovered from commercially processed chicken carcasses using whole genome sequencing, phenotype characterizations and an intracellular killing assay. Illumina MiSeq platform was used for sequencing of two Salmonella genomes. Phylogenetic analysis employing homologous alignment of a 1,185 non-duplicated protein-coding gene in the Salmonella core genome demonstrated fully resolved bifurcating patterns with varying levels of diversity that separated ST221_31B and SK222_32B genomes into distinct monophyletic serovar clades. Single nucleotide polymorphism (SNP) analysis identified 2,432 (ST19) SNPs within 13 Typhimurium genomes including ST221_31B representing Sequence Type ST19 and 650 (ST152) SNPs were detected within 13 Kentucky genomes including SK222_32B representing Sequence Type ST152. In addition to serovar-specific conserved coding sequences, the genomes of ST221_31B and SK222_32B harbor several genomic regions with significant genetic differences. These included phage and phage-like elements, carbon utilization or transport operons, fimbriae operons, putative membrane associated protein-encoding genes, antibiotic resistance genes, siderophore operons, and numerous hypothetical protein-encoding genes. Phenotype microarray results demonstrated that ST221_31B is capable of utilizing certain carbon compounds more efficiently as compared to SK222_3B; namely, 1,2-propanediol, M-inositol, L-threonine, α-D-lactose, D-tagatose, adonitol, formic acid, acetoacetic acid, and L-tartaric acid. ST221_31B survived for 48 h in macrophages, while SK222_32B was mostly eliminated. Further, a 3-fold growth of ST221_31B was observed at 24 hours

Prevalence and Characterization of Salmonella in Animal Meals Collected from Rendering Operations.

PubMed

Jiang, Xiuping

2016-06-01

As part of the Salmonella Education Reduction Program, the Animal Protein Producers Industry initiated a yearlong microbiological survey of animal meals from 1 January to 31 December 2010. The types of animal meals included poultry meal, pork and beef crax, meat meal, meat and bone meal, feather meal, blood meal, and fish meal from a variety of rendering operations (n = 65). Salmonella was positive in 731 (8.3%) of 8,783 analyzed samples, with contamination rates as 1.0, 33.2, and 21.3% from samples collected right after press, being loaded out, or unidentified, respectively. The randomly selected positive Salmonella samples (n = 100) representing 1.1% of the total samples tested were enumerated by the most-probable-number (MPN) method. The Salmonella contamination level ranged from <0.03 (below the detection limit) to 240 MPN/g with a median MPN per gram of 0.036. Among 102 Salmonella isolates from those 100 positive samples, a total of 42 Salmonella serotypes or groups were identified with Montevideo (13%), Senftenberg (11%), Mbandaka (7%), Orion (7%), Livingstone (6%), Tennessee (4%), Infantis (4%), Cerro (4%), and group C1 (4%) as the most predominant ones. Those Salmonella isolates were further analyzed for antimicrobial resistance to the 15 most common antibiotics by using the National Antimicrobial Resistance Monitoring System gram-negative plate. Most Salmonella isolates (n = 94) were sensitive to all antibiotics tested, with seven isolates resistant to one antibiotic and one resistant to seven antibiotics. Clearly, the prevalence of Salmonella in animal meals declined compared with previous surveys, and none of the Salmonella serotypes concerning target animal health were isolated. In addition, most Salmonella isolates remained susceptible to the majority of the 15 most commonly used antibiotics.

Immunity to intestinal pathogens: lessons learned from Salmonella

PubMed Central

McSorley, Stephen J.

2014-01-01

Summary Salmonella are a common source of food or water-borne infection and cause a wide range of clinical disease in human and animal hosts. Salmonella are relatively easy to culture and manipulate in a laboratory setting, and the infection of laboratory animals induces robust innate and adaptive immune responses. Thus, immunologists have frequently turned to Salmonella infection models to expand understanding of immunity to intestinal pathogens. In this review, I summarize current knowledge of innate and adaptive immunity to Salmonella and highlight features of this response that have emerged from recent studies. These include the heterogeneity of the antigen-specific T-cell response to intestinal infection, the prominence of microbial mechanisms to impede T and B-cell responses, and the contribution of non-cognate pathways for elicitation of T-cell effector functions. Together, these different issues challenge an overly simplistic view of host-pathogen interaction during mucosal infection but also allow deeper insight into the real-world dynamic of protective immunity to intestinal pathogens. PMID:24942689

Isolation and identification of Salmonella spp. in environmental water by molecular technology in Taiwan

NASA Astrophysics Data System (ADS)

Kuo, Chun Wei; Hao Huang, Kuan; Hsu, Bing Mu; Tsai, Hsien Lung; Tseng, Shao Feng; Shen, Tsung Yu; Kao, Po Min; Shen, Shu Min; Chen, Jung Sheng

2013-04-01

Salmonella spp. is one of the most important causal agents of waterborne diseases. The taxonomy of Salmonella is very complicated and its genus comprises more than 2,500 serotypes. The detection of Salmonella in environmental water samples by routines culture methods using selective media and characterization of suspicious colonies based on biochemical tests and serological assay are generally time consuming. To overcome this drawback, it is desirable to use effective method which provides a higher discrimination and more rapid identification about Salmonella in environmental water. The aim of this study is to investigate the occurrence of Salmonella using molecular technology and to identify the serovars of Salmonella isolates from 70 environmental water samples in Taiwan. The analytical procedures include membrane filtration, non-selective pre-enrichment, selective enrichment of Salmonella. After that, we isolated Salmonella strains by selective culture plates. Both selective enrichment and culture plates were detected by Polymerase Chain Reaction (PCR). Finally, the serovars of Salmonella were confirmed by using biochemical tests and serological assay. In this study, 15 water samples (21.4%) were identified as Salmonella by PCR. The positive water samples will further identify their serotypes by culture method. The presence of Salmonella in environmental water indicates the possibility of waterborne transmission in drinking watershed. Consequently, the authorities need to provide sufficient source protection and to maintain the system for disease prevention. Keywords: Salmonella spp., serological assay, PCR

Comparative performance of three sampling techniques to detect airborne Salmonella species in poultry farms.

PubMed

Adell, Elisa; Moset, Verónica; Zhao, Yang; Jiménez-Belenguer, Ana; Cerisuelo, Alba; Cambra-López, María

2014-01-01

Sampling techniques to detect airborne Salmonella species (spp.) in two pilot scale broiler houses were compared. Broilers were inoculated at seven days of age with a marked strain of Salmonella enteritidis. The rearing cycle lasted 42 days during the summer. Airborne Salmonella spp. were sampled weekly using impaction, gravitational settling, and impingement techniques. Additionally, Salmonella spp. were sampled on feeders, drinkers, walls, and in the litter. Environmental conditions (temperature, relative humidity, and airborne particulate matter (PM) concentration) were monitored during the rearing cycle. The presence of Salmonella spp. was determined by culture-dependent and molecular methods. No cultivable Salmonella spp. were recovered from the poultry houses' surfaces, the litter, or the air before inoculation. After inoculation, cultivable Salmonella spp. were recovered from the surfaces and in the litter. Airborne cultivable Salmonella spp. Were detected using impaction and gravitational settling one or two weeks after the detection of Salmonella spp. in the litter. No cultivable Salmonella spp. were recovered using impingement based on culture-dependent techniques. At low airborne concentrations, the use of impingement for the quantification or detection of cultivable airborne Salmonella spp. is not recommended. In these cases, a combination of culture-dependent and culture-independent methods is recommended. These data are valuable to improve current measures to control the transmission of pathogens in livestock environments and for optimising the sampling and detection of airborne Salmonella spp. in practical conditions.

Detection of Salmonella bacterium in drinking water using microring resonator.

PubMed

Bahadoran, Mahdi; Noorden, Ahmad Fakhrurrazi Ahmad; Mohajer, Faeze Sadat; Abd Mubin, Mohamad Helmi; Chaudhary, Kashif; Jalil, Muhammad Arif; Ali, Jalil; Yupapin, Preecha

2016-01-01

A new microring resonator system is proposed for the detection of the Salmonella bacterium in drinking water, which is made up of SiO2-TiO2 waveguide embedded inside thin film layer of the flagellin. The change in refractive index due to the binding of the Salmonella bacterium with flagellin layer causes a shift in the output signal wavelength and the variation in through and drop port's intensities, which leads to the detection of Salmonella bacterium in drinking water. The sensitivity of proposed sensor for detecting of Salmonella bacterium in water solution is 149 nm/RIU and the limit of detection is 7 × 10(-4)RIU.

75 FR 66769 - Draft Compliance Policy Guide Sec. 690.800 Salmonella

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-29

...] Draft Compliance Policy Guide Sec. 690.800 Salmonella in Animal Feed; Availability; Extension of Comment... that are adulterated due to the presence of Salmonella. The Agency is taking this action in response to... action against animal feed or feed ingredients that are adulterated due to the presence of Salmonella...

Evaluation of recombinant porin (rOmp2a) protein as a potential antigen candidate for serodiagnosis of Human Brucellosis.

PubMed

Pathak, Prachi; Kumar, Ashu; Thavaselvam, Duraipandian

2017-07-11

Brucellosis is an important zoonotic disease caused by different Brucella species and human brucellosis is commonly prevalent in different states of India. Among various Brucella species, B. melitensis is most pathogenic to human and included as category B biothreat which can cause infection through aerosol, cut, wounds in skin and contact with infected animals. The diagnosis of human brucellosis is very important for proper treatment and management of disease as there is no vaccine available for human use. The present study was designed to clone, express and purify immunodominant recombinant omp2a (rOmp2a) porin protein of B. melitensis and to evaluate this new antigen candidate for specific serodiagnosis of human brucellosis by highly sensitive iELISA (indirect enzyme linked immunosorbent assay). Omp2a gene of B. melitensis 16 M strain was cloned and expressed in pET-SUMO expression system. The recombinant protein was purified under denaturing conditions using 8 M urea. The purified recombinant protein was confirmed by western blotting by reacting with anti-HIS antibody. The sero-reactivity of the recombinant protein was also checked by reacting with antisera of experimentally infected mice with B. melitensis 16 M at different time points. Serodiagnostic potential of recombinant porin antigen was tested against 185 clinical serum samples collected from regions endemic to brucellosis in southern part of India by iELISA. The samples were grouped into five groups. Group 1 contained cultured confirmed positive serum samples of brucellosis (n = 15), group 2 contained sera samples from positive cases of brucellosis previously tested by conventional methods of RBPT (n = 28) and STAT (n = 26), group 3 contained sera samples negative by RBPT(n = 36) and STAT (n = 32), group 4 contained sera samples of other febrile illness and PUO case (n = 35) and group 5 contained confirmed negative sera samples from healthy donors (n = 23). The rOmp2a was found to be

Salmonella Typhimurium and Salmonella Sofia: Growth in and Persistence on Eggs under Production and Retail Conditions

PubMed Central

McAuley, Catherine M.; Duffy, Lesley L.; Subasinghe, Nela; Hogg, Geoff; Coventry, John; Fegan, Narelle

2015-01-01

Salmonellosis in Australia has been linked to eggs and egg products with specific serotypes associated with outbreaks. We compared attachment to and survival on egg shells and growth in eggs of two Salmonella serotypes, an egg outbreak associated Salmonella Typhimurium and a non-egg-associated Salmonella enterica ssp. II 1,4,12,27:b:[e,n,x] (S. Sofia). Experiments were conducted at combinations of 4, 15, 22, 37 and 42°C. No significant differences occurred between the serotypes in maximum growth rates, which were significantly greater (P < 0.001) in egg yolk (0.427 log10 CFU/mL/h) compared to whole egg (0.312 log10 CFU/mL/h) and egg white (0.029 log10 CFU/mL/h). Attachment to egg shells varied by time (1 or 20 min) and temperature (4, 22 and 42°C), with S. Typhimurium isolates attaching at higher levels (P < 0.05) than S. Sofia after 1 min at 4°C and S. Typhimurium ATCC 14028 attaching at higher (P < 0.05) levels at 22°C. Survival on egg shells was not significantly different across isolates. Salmonella serotypes behaved similarly regarding growth in egg contents, attachment to egg shells and survival on eggs, indicating that other factors more likely contributed to reasons for S. Typhimurium being implicated in multiple egg-associated outbreaks. PMID:26539536

Detection and classification of salmonella serotypes using spectral signatures collected by fourier transform infrared (FT-IR) spectroscopy

USDA-ARS?s Scientific Manuscript database

Spectral signatures of Salmonella serotypes namely Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg and Salmonella Kentucky were collected using Fourier transform infrared spectroscopy (FT-IR). About 5-10 µL of Salmonella suspensions with concentrations of 1...

Characterization and Antimicrobial Resistance of Salmonella Typhimurium Isolates from Clinically Diseased Pigs in Korea.

PubMed

Oh, Sang-Ik; Kim, Jong Wan; Chae, Myeongju; Jung, Ji-A; So, Byungjae; Kim, Bumseok; Kim, Ha-Young

2016-11-01

This study investigated the prevalence of Salmonella enterica serovar and antimicrobial resistance in Salmonella Typhimurium isolates from clinically diseased pigs collected from 2008 to 2014 in Korea. Isolates were also characterized according to the presence of antimicrobial resistance genes and pulsed-field gel electrophoresis patterns. Among 94 Salmonella isolates, 81 (86.2%) were identified as being of the Salmonella Typhimurium serotype, followed by Salmonella Derby (6 of 94, 6.4%), Salmonella 4,[5],12:i:- (4 of 94, 4.3%), Salmonella Enteritidis (2 of 94, 2.1%), and Salmonella Brandenburg (1 of 94, 1.1%). The majority of Salmonella Typhimurium isolates were resistant to tetracycline (92.6%), followed by streptomycin (88.9%) and ampicillin (80.2%). Overall, 96.3% of Salmonella Typhimurium isolates showed multidrug-resistant phenotypes and commonly harbored the resistance genes bla TEM (64.9%), flo (32.8%), aadA (55.3%), strA (58.5%), strB (58.5%), sulII (53.2%), and tetA (61.7%). The pulsed-field gel electrophoresis analysis of 45 Salmonella Typhimurium isolates from individual farms revealed 27 distinct patterns that formed one major and two minor clusters in the dendrogram analysis, suggesting that most of the isolates (91.1%) from diseased pigs were genetically related. These findings can assist veterinarians in the selection of appropriate antimicrobial agents to combat Salmonella Typhimurium infections in pigs. Furthermore, they highlight the importance of continuous surveillance of antimicrobial resistance and genetic status in Salmonella Typhimurium for the detection of emerging resistance trends.

Injury and death of various Salmonella serotypes due to acidic conditions

USDA-ARS?s Scientific Manuscript database

Acid injury of Salmonella could prevent detection of Salmonella in feed and feed-type samples. A previous study showed that after incubation in commonly used pre-enrichment media, mixed feeds and feed ingredients reached a pH (4.0 to 5.0) capable of injuring or killing Salmonella. Approximately 10...

Salmonella serovar-specific interaction with jejunal epithelial cells.

PubMed

Razzuoli, Elisabetta; Amadori, Massimo; Lazzara, Fabrizio; Bilato, Dania; Ferraris, Monica; Vito, Guendalina; Ferrari, Angelo

2017-08-01

Gut is often a receptacle for many different pathogens in feed and/or the environment, such as Salmonella spp. The current knowledge about pathogenicity of Salmonella is restricted to few serotypes, whereas other important ones like S. Coeln, S. Thompson, S. Veneziana, have not been investigated yet in human and animal models. Therefore, the aim of our work was to verify the ability of widespread environmental Salmonella strains to penetrate and modulate innate immunity in pig intestinal IPEC-J2 cells. Our results outline the different ability of Salmonella strains to modulate innate immunity; the expression of the IFN-β gene was increased by S. Typhimurium, S. Ablogame and S. Diarizonae 2, that also caused an inflammatory response in terms of Interleukin (IL)-1β and/or IL-8 gene espression. In particular, IL-8 gene expression and protein release were significantly modulated by 5 Salmonella strains out of 7. Interestingly, S. Typhimurium, S. Coeln and S. Thompson strains, characterized by a peculiar ability to penetrate into IPEC-J2 cells, up-regulated both IL-8 and TNF-α gene expression. Accordingly, blocking IL-8 was shown to decrease the penetration of S. Typhimurium. On the contrary, S. Diarizonae strain 1, showing lesser invasion of IPEC-J2 cells, down-regulated the p38-MAPK pathway, and it did not induce an inflammatory response. Our results confirm that IPEC-J2 cells are a useful model to evaluate host-gut pathogen interaction and indicate IL-8 and TNF-α as possible predictive markers of invasiveness of Salmonella strains in enterocytes. Copyright © 2017 Elsevier B.V. All rights reserved.

Salmonella Urinary Tract Infection Heralding Thoracic Mycotic Aneurysm: Case Report as Medical Apology

PubMed Central

White, Jennifer L.; Golfus, Gabriel R.; Sadosty, Annie T.

2017-01-01

We report a case as a patient apology as a means of teaching other physicians about a unique presentation of a rare disease. Salmonella species are unusually isolated organisms in urine. In the case described, appreciation for the rarity of Salmonella species in the urine facilitated recognition of a serious disseminated Salmonella infection. Physicians should consider disseminated Salmonella infection, as was found in a patient with an aortic mycotic an eurysm, after isolation of Salmonella in urine despite an initially benign clinical presentation.

Effect of dietary supplementation of nitrocompounds on salmonella colonization and ileal immune gene expression in laying hens challenged with salmonella enteritidis

USDA-ARS?s Scientific Manuscript database

Foodborne disease caused by Salmonella Enteritidis (SE) is one of the important public health and economic concerns. A study was conducted to determine the effect of supplementation with 2-nitroethanol (NE) and 2-nitropropanol (NP) on Salmonella recovery of internal organs as well as on the immune g...

Use of enrichment real-time PCR to enumerate salmonella on chicken parts.

PubMed

Oscar, T P

2014-07-01

Salmonella bacteria that survive cooking or that cross-contaminate other food during meal preparation and serving represent primary routes of consumer exposure to this pathogen from chicken. In the present study, enrichment real-time PCR (qPCR) was used to enumerate Salmonella bacteria that contaminate raw chicken parts at retail or that cross-contaminate cooked chicken during simulated meal preparation and serving. Whole raw chickens obtained at retail were partitioned into wings, breasts, thighs, and drumsticks using a sterilized knife and cutting board, which were then used to partition a cooked chicken breast to assess cross-contamination. After enrichment in buffered peptone water (400 ml, 8 h, 40°C, 80 rpm), subsamples were used for qPCR and cultural isolation of Salmonella. In some experiments, chicken parts were spiked with 0 to 3.6 log of Salmonella Typhimurium var. 5- to generate a standard curve for enumeration by qPCR. Of 10 raw chickens examined, 7 (70%) had one or more parts contaminated with Salmonella. Of 80 raw parts examined, 15 (19%) were contaminated with Salmonella. Of 20 cooked chicken parts examined, 2 (10%) were cross-contaminated with Salmonella. Predominant serotypes identified were Typhimurium (71%) and its variants (var. 5-, monophasic, and nonmotile) and Kentucky (18%). The number of Salmonella bacteria on contaminated parts ranged from one to two per part. Results of this study indicated that retail chicken parts examined were contaminated with low levels of Salmonella, which resulted in low levels of cross-contamination during simulated meal preparation and serving. Thus, if consumers properly handle and prepare the chicken, it should pose no or very low risk of consumer exposure to Salmonella.

Real-Time PCR Method for Detection of Salmonella spp. in Environmental Samples.

PubMed

Kasturi, Kuppuswamy N; Drgon, Tomas

2017-07-15

The methods currently used for detecting Salmonella in environmental samples require 2 days to produce results and have limited sensitivity. Here, we describe the development and validation of a real-time PCR Salmonella screening method that produces results in 18 to 24 h. Primers and probes specific to the gene invA , group D, and Salmonella enterica serovar Enteritidis organisms were designed and evaluated for inclusivity and exclusivity using a panel of 329 Salmonella isolates representing 126 serovars and 22 non- Salmonella organisms. The invA - and group D-specific sets identified all the isolates accurately. The PCR method had 100% inclusivity and detected 1 to 2 copies of Salmonella DNA per reaction. Primers specific for Salmonella -differentiating fragment 1 (Sdf-1) in conjunction with the group D set had 100% inclusivity for 32 S Enteritidis isolates and 100% exclusivity for the 297 non-Enteritidis Salmonella isolates. Single-laboratory validation performed on 1,741 environmental samples demonstrated that the PCR method detected 55% more positives than the V itek i mmuno d iagnostic a ssay s ystem (VIDAS) method. The PCR results correlated well with the culture results, and the method did not report any false-negative results. The receiver operating characteristic (ROC) analysis documented excellent agreement between the results from the culture and PCR methods (area under the curve, 0.90; 95% confidence interval of 0.76 to 1.0) confirming the validity of the PCR method. IMPORTANCE This validated PCR method detects 55% more positives for Salmonella in half the time required for the reference method, VIDAS. The validated PCR method will help to strengthen public health efforts through rapid screening of Salmonella spp. in environmental samples.

Real-Time PCR Method for Detection of Salmonella spp. in Environmental Samples

PubMed Central

Drgon, Tomas

2017-01-01

ABSTRACT The methods currently used for detecting Salmonella in environmental samples require 2 days to produce results and have limited sensitivity. Here, we describe the development and validation of a real-time PCR Salmonella screening method that produces results in 18 to 24 h. Primers and probes specific to the gene invA, group D, and Salmonella enterica serovar Enteritidis organisms were designed and evaluated for inclusivity and exclusivity using a panel of 329 Salmonella isolates representing 126 serovars and 22 non-Salmonella organisms. The invA- and group D-specific sets identified all the isolates accurately. The PCR method had 100% inclusivity and detected 1 to 2 copies of Salmonella DNA per reaction. Primers specific for Salmonella-differentiating fragment 1 (Sdf-1) in conjunction with the group D set had 100% inclusivity for 32 S. Enteritidis isolates and 100% exclusivity for the 297 non-Enteritidis Salmonella isolates. Single-laboratory validation performed on 1,741 environmental samples demonstrated that the PCR method detected 55% more positives than the Vitek immunodiagnostic assay system (VIDAS) method. The PCR results correlated well with the culture results, and the method did not report any false-negative results. The receiver operating characteristic (ROC) analysis documented excellent agreement between the results from the culture and PCR methods (area under the curve, 0.90; 95% confidence interval of 0.76 to 1.0) confirming the validity of the PCR method. IMPORTANCE This validated PCR method detects 55% more positives for Salmonella in half the time required for the reference method, VIDAS. The validated PCR method will help to strengthen public health efforts through rapid screening of Salmonella spp. in environmental samples. PMID:28500041

Prevalence of Salmonella on raw poultry at retail markets in China.

PubMed

Yang, Baowei; Xi, Meili; Wang, Xin; Cui, Shenghui; Yue, Tianli; Hao, Hongshan; Wang, Yin; Cui, Yue; Alali, W Q; Meng, Jianghong; Walls, Isabel; Wong, D M Lo Fo; Doyle, M P

2011-10-01

Data regarding Salmonella on raw poultry are very limited in China. The objective of this study was to determine the prevalence of Salmonella on raw poultry at the retail level in six provinces and two national cities in China. Whole chicken carcasses (n = 1,152) were collected from three types of retail markets (large, small, and wet). All samples were analyzed for the presence of Salmonella by using the U.S. Department of Agriculture, Food Safety Inspection Service method. Of 1,152 chicken samples, overall Salmonella prevalence was 52.2%. The highest prevalence was observed in Guangxi Province (65.3%), next in Guangdong Province (64.6%), and then in Beijing (63.9%), Shaanxi Province (50.7%), Henan Province (47.9%), Shanghai (44.4%), and Fujian Province (42.4%), and lowest prevalence was observed in Sichuan Province (38.9%). Salmonella prevalence was significantly different among the six provinces and two national cities. Salmonella prevalence was highest in the wet markets (54.4%) compared with the large markets (50.3%) and the small markets (52.1%), but differences were not significant (P > 0.05). Good manufacturing practices, good agricultural practices, and hazard analysis critical control point systems for Salmonella control in poultry production at the farm, processing, and retail level should be implemented.

Prevalence of Salmonella in the broiler supply chain in The Netherlands.

PubMed

Van Der Fels-Klerx, H J; Jacobs-Reitsma, W F; Van Brakel, R; Van Der Voet, H; Van Asselt, E D

2008-10-01

This article presents detailed information on Salmonella prevalence throughout the broiler supply chain in The Netherlands, based on results from a national monitoring program. Data were collected during the period 2002 through 2005 and from six sampling points in the chain, covering hatchery up to and including processing. Trends in Salmonella prevalence over years and seasons were analyzed as well as the effect of slaughterhouse capacity on these trends. In addition, correlations between the occurrence of Salmonella at the various sampling points were calculated. The results showed a decreasing trend of Salmonella prevalence from 2002 through 2005 at all sampling points. A seasonal effect on the occurrence of Salmonella was found at the broiler farm, with a higher prevalence during the third and fourth quarter of the year (July through December). The higher the capacity of the slaughterhouse, the lower Salmonella prevalence on arrival at the slaughterhouse and the higher the prevalence at the end of slaughter and the end of processing. The detailed insights obtained in this study could be used to focus future field and experimental research on the prevention and control of Salmonella in the broiler supply chain. Results presented could also be used in risk assessment studies.

Foodborne Salmonella control

USDA-ARS?s Scientific Manuscript database

Almost all of the paratyphoid Salmonella spp. are normal flora bacteria of the intestines of chickens and turkeys. They cohabit together and have a very comfortable living arrangement, causing little or no harm to one another and seldom attracting much attention from the birds’ defense systems. Th...

Rodents as a Source of Salmonella Contamination in Wet Markets in Thailand.

PubMed

Ribas, Alexis; Saijuntha, Weerachai; Agatsuma, Takeshi; Prantlová, Veronika; Poonlaphdecha, Srisupaph

2016-08-01

Few studies have been conducted on the presence of Salmonella in the rodents that inhabit the wet markets that play an important role in daily life in Southeast Asia. The results of studies of rodents as carriers of Salmonella vary greatly, ranging from an absence of Salmonella to high prevalences. Previous studies investigated habitats such as farms and urban and wild areas where there is less rodent-human interaction than in wet markets. Consequently, the potential role of rodents as reservoirs and transmitters of Salmonella in wet markets is of great interest. Rodents were trapped in eight traditional wet markets in Thailand and identified to species level. Subsequently, they were screened for Salmonella and isolates were serotyped. A total of 110 rats (Rattus norvegicus and Rattus exulans) were examined. Overall, the prevalence of Salmonella in rats was 49.10%, but varied between 0% and 73.3% among markets. Three serovars were identified: Salmonella Typhimurium (30%), S. Weltevreden (12.7%), and S. 4,[5],12:i:- (6.4%). Our results show that rodents in wet markets are a potential reservoir of Salmonella due to the close contact they have with humans and food. The three isolated serovars, of which serovar S. 4,[5],12:i:- is reported for the first time in rodents, are among the 10 commonest serovars isolated from humans in Thailand. Thus, more attention should be paid to rodents as potential reservoirs of Salmonella.

Salmonella survival in manure-treated soils during simulated seasonal temperature exposure.

PubMed

Holley, Richard A; Arrus, Katia M; Ominski, Kimberly H; Tenuta, Mario; Blank, Gregory

2006-01-01

Addition of animal manure to soil can provide opportunity for Salmonella contamination of soil, water, and food. This study examined how exposure of hog manure-treated loamy sand and clay soils to different simulated seasonal temperature sequences influenced the length of Salmonella survival. A six-strain cocktail of Salmonella serovars (Agona, Hadar, Heidelberg, Montevideo, Oranienburg, and Typhimurium) was added to yield 5 log cfu/g directly to about 5 kg of the two soils and moisture adjusted to 60 or 80% of field capacity (FC). Similarly, the Salmonella cocktail was mixed with fresh manure slurry from a hog nursery barn and the latter added to the two soils at 25 g/kg to achieve 5 log cfu/g Salmonella. Manure was mixed either throughout the soil or with the top kilogram of soil and the entire soil volume was adjusted to 60 or 80% FC. Soil treatments were stored 180 d at temperature sequences representing winter to summer (-18, 4, 10, 25 degrees C), spring to summer (4, 10, 25, 30 degrees C), or summer to winter (25, 10, 4, -18 degrees C) seasonal periods with each temperature step lasting 45 d. Samples for Salmonella recovery by direct plating or enrichment were taken at 0, 7, and 15 d post-inoculation and thereafter at 15-d intervals to 180 d. Salmonella numbers decreased during application to soil and the largest decreases occurred within the first week. Higher soil moisture, manure addition, and storage in the clay soil increased Salmonella survival. Salmonella survived longest (> or = 180 d) in both soils during summer-winter exposure but was not isolated after 160 d from loamy sand soil exposed to other seasonal treatments. For all but one treatment decimal reduction time (DRT45d) values calculated from the first 45 d after application were < or = 30 d and suggested that a 30-d delay between field application of manure in the spring or fall and use of the land would provide reasonable assurance that crop and animal contamination by Salmonella would be

Reduction of Salmonella in skinless chicken breast fillets by lauric arginate surface application.

PubMed

Sharma, C S; Ates, A; Joseph, P; Nannapaneni, R; Kiess, A

2013-05-01

Lauric arginate (LAE) has been found to be effective against various foodborne pathogens. In this study, the antimicrobial efficacy of LAE against Salmonella and mesophilic organisms was evaluated in fresh, skinless, boneless, uncooked chicken breast fillets. The effect of LAE treatments on pH and color of breast fillets was also assessed. Chicken breast fillets were inoculated with a 4-strain Salmonella cocktail (Salmonella Enteritidis ATCC 4931, Salmonella Heidelberg ATCC 8326, Salmonella Kentucky ATCC 9263, and Salmonella Typhimurium ATCC 14028) and then treated with sterile dionized water (positive control) and 200 ppm and 400 ppm of LAE. The chicken breast fillets were stored at 4 ± 1°C and analyzed on d 0, 1, 3, 5, and 7 for Salmonella, total aerobes, color, and pH. The fillets destined for color analysis were not inoculated with Salmonella cocktail and stored under conditions simulating the retail display. The fillets treated with 400 ppm LAE had lower (P < 0.05) Salmonella counts compared with the positive control from d 0 through d 7 of storage except on d 3, when no effect of LAE was observed. Treating fillets with 200 ppm of LAE caused a significant reduction in Salmonella counts (P < 0.1) on d 0, 1, and 7. Reductions in Salmonella spp. were 0.7 log cfu/g and 0.7 to 1.0 log cfu/g for 200 and 400 ppm treatments, respectively. Lauric arginate did not exhibit any treatment effect on the growth of mesophilic microorganisms, pH, and color of chicken breast fillets (P > 0.05) when applied at 200 and 400 ppm concentrations. These results indicate that surface application of LAE in chicken breast fillets significantly reduces Salmonella during refrigerated aerobic storage without negatively affecting the color of chicken breast fillets.

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

PubMed Central

Gole, Vaibhav C.; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret

2016-01-01

ABSTRACT The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates (n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA, ironA, and misL. There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems.

PubMed

Gole, Vaibhav C; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret; Chousalkar, Kapil

2017-03-01

The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates ( n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA , ironA , and misL There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in

Diversification of the Salmonella Fimbriae: A Model of Macro- and Microevolution

PubMed Central

Yue, Min; Rankin, Shelley C.; Blanchet, Ryan T.; Nulton, James D.; Edwards, Robert A.; Schifferli, Dieter M.

2012-01-01

Bacteria of the genus Salmonella comprise a large and evolutionary related population of zoonotic pathogens that can infect mammals, including humans and domestic animals, birds, reptiles and amphibians. Salmonella carries a plethora of virulence genes, including fimbrial adhesins, some of them known to participate in mammalian or avian host colonization. Each type of fimbria has its structural subunit and biogenesis genes encoded by one fimbrial gene cluster (FGC). The accumulation of new genomic information offered a timely opportunity to better evaluate the number and types of FGCs in the Salmonella pangenome, to test the use of current classifications based on phylogeny, and to infer potential correlations between FGC evolution in various Salmonella serovars and host niches. This study focused on the FGCs of the currently deciphered 90 genomes and 60 plasmids of Salmonella. The analysis highlighted a fimbriome consisting of 35 different FGCs, of which 16 were new, each strain carrying between 5 and 14 FGCs. The Salmonella fimbriome was extremely diverse with FGC representatives in 8 out of 9 previously categorized fimbrial clades and subclades. Phylogenetic analysis of Salmonella suggested macroevolutionary shifts detectable by extensive FGC deletion and acquisition. In addition, microevolutionary drifts were best depicted by the high level of allelic variation in predicted or known adhesins, such as the type 1 fimbrial adhesin FimH for which 67 different natural alleles were identified in S. enterica subsp. I. Together with strain-specific collections of FGCs, allelic variation among adhesins attested to the pathoadaptive evolution of Salmonella towards specific hosts and tissues, potentially modulating host range, strain virulence, disease progression, and transmission efficiency. Further understanding of how each Salmonella strain utilizes its panel of FGCs and specific adhesin alleles for survival and infection will support the development of new approaches

Salmonella serovars and their distribution in Nigerian commercial chicken layer farms

PubMed Central

Fagbamila, Idowu Oluwabunmi; Barco, Lisa; Mancin, Marzia; Kwaga, Jacob; Ngulukun, Sati Samuel; Zavagnin, Paola; Lettini, Antonia Anna; Lorenzetto, Monica; Abdu, Paul Ayuba; Kabir, Junaidu; Umoh, Jarlath; Ricci, Antonia; Muhammad, Maryam

2017-01-01

Commercial poultry farms (n° 523), located in all the six regions of Nigeria were sampled with a view to generate baseline information about the distribution of Salmonella serovars in this country. Five different matrices (litter, dust, faeces, feed and water) were collected from each visited farm. Salmonella was isolated from at least one of the five matrices in 228 farms, with a farm prevalence of 43.6% (CI95[39.7–48.3%]). Altogether, 370 of 2615 samples collected (14.1%, CI95[12.8; 15.5%]) contained Salmonella. Considering the number of positive farms and the number of positive samples, it was evident that for the majority of the sampled farms, few samples were positive for Salmonella. With regard to the matrices, there was no difference in Salmonella prevalence among the five matrices considered. Of the 370 isolates serotyped, eighty-two different serotypes were identified and Salmonella Kentucky was identified as having the highest isolation rate in all the matrices sampled (16.2%), followed by S. Poona and S. Elisabethville. S. Kentucky was distributed across the country, whereas the other less frequent serovars had a more circumscribed diffusion. This is one of few comprehensive studies on the occurrence and distribution of Salmonella in commercial chicken layer farms from all the six regions of Nigeria. The relatively high prevalence rate documented in this study may be attributed to the generally poor infrastructure and low biosecurity measures in controlling stray animals, rodents and humans. Data collected could be valuable for instituting effective intervention strategies for Salmonella control in Nigeria and also in other developing countries with a similar poultry industry structure, with the final aim of reducing Salmonella spread in animals and ultimately in humans. PMID:28278292

Salmonella serovars and their distribution in Nigerian commercial chicken layer farms.

PubMed

Fagbamila, Idowu Oluwabunmi; Barco, Lisa; Mancin, Marzia; Kwaga, Jacob; Ngulukun, Sati Samuel; Zavagnin, Paola; Lettini, Antonia Anna; Lorenzetto, Monica; Abdu, Paul Ayuba; Kabir, Junaidu; Umoh, Jarlath; Ricci, Antonia; Muhammad, Maryam

2017-01-01

Commercial poultry farms (n° 523), located in all the six regions of Nigeria were sampled with a view to generate baseline information about the distribution of Salmonella serovars in this country. Five different matrices (litter, dust, faeces, feed and water) were collected from each visited farm. Salmonella was isolated from at least one of the five matrices in 228 farms, with a farm prevalence of 43.6% (CI95[39.7-48.3%]). Altogether, 370 of 2615 samples collected (14.1%, CI95[12.8; 15.5%]) contained Salmonella. Considering the number of positive farms and the number of positive samples, it was evident that for the majority of the sampled farms, few samples were positive for Salmonella. With regard to the matrices, there was no difference in Salmonella prevalence among the five matrices considered. Of the 370 isolates serotyped, eighty-two different serotypes were identified and Salmonella Kentucky was identified as having the highest isolation rate in all the matrices sampled (16.2%), followed by S. Poona and S. Elisabethville. S. Kentucky was distributed across the country, whereas the other less frequent serovars had a more circumscribed diffusion. This is one of few comprehensive studies on the occurrence and distribution of Salmonella in commercial chicken layer farms from all the six regions of Nigeria. The relatively high prevalence rate documented in this study may be attributed to the generally poor infrastructure and low biosecurity measures in controlling stray animals, rodents and humans. Data collected could be valuable for instituting effective intervention strategies for Salmonella control in Nigeria and also in other developing countries with a similar poultry industry structure, with the final aim of reducing Salmonella spread in animals and ultimately in humans.

Cloning and nucleotide sequence of the Pseudomonas aeruginosa glucose-selective OprB porin gene and distribution of OprB within the family Pseudomonadaceae.

PubMed

Wylie, J L; Worobec, E A

1994-03-01

OprB is a glucose-selective porin known to be produced by Pseudomonas aeruginosa and Pseudomonas putida. We have cloned and sequenced the oprB gene of P. aeruginosa and obtained expression of OprB in Escherichia coli. The mature protein consists of 423 amino acid residues with a deduced molecular mass of 47597 Da. Several clusters of amino acid residues, potentially involved in the structure or function of the protein, were identified. An area of regional homology with E. coli LamB was also identified. Carbohydrate-inducible proteins, potentially homologous to OprB, were identified in several rRNA homology-group-I pseudomonads by sodium dodecyl sulfate/polyacrylamide gel electrophoresis analysis, Western immunoblotting and N-terminal amino acid sequencing. These species also contained DNA that hybridized to a P. aeruginosa oprB gene probe.

Prevalence and Spatial Distribution of Salmonella Infections in the Pennsylvania Raccoon (Procyon lotor).

PubMed

Very, K J; Kirchner, M K; Shariat, N; Cottrell, W; Sandt, C H; Dudley, E G; Kariyawasam, S; Jayarao, B M

2016-05-01

A study was conducted to determine the prevalence and spatial distribution of Salmonella infection in Pennsylvania raccoons (Procyon lotor), common wildlife mammals known to occupy overlapping habitats with humans and domestic food animals. The Pennsylvania Game Commission provided a total of 371 raccoon intestinal samples from trapped and road-killed raccoons collected between May and November 2011. Salmonella was isolated from the faeces of 56 (15.1%) of 371 raccoons in 35 (54%) of 65 counties across Pennsylvania. The five most frequently isolated serotypes were Newport (28.6%), Enteritidis (19.6%), Typhimurium (10.7%), Braenderup (8.9%) and Bareilly (7.1%). Pulsed-field gel electrophoresis (PFGE) analysis of the Salmonella isolates and subsequent comparison to the Pennsylvania Department of Health human Salmonella PFGE database revealed 16 different pulsetypes in Salmonella isolates recovered from raccoons that were indistinguishable from pulsetypes of Salmonella collected from clinically ill humans during the study period. The pulsetypes of seven raccoon Salmonella isolates matched those of 56 human Salmonella isolates by month and geographical region of sample collection. Results from Clustered Regularly Interspaced Short Palindromic Repeats and Multi-Virulence Locus Sequence Typing (CRISPR-MVLST) analysis corroborated the PFGE and serotyping data. The findings of this study show that several PFGE pulsetypes of Salmonella were shared between humans and raccoons in Pennsylvania, indicating that raccoons and humans might share the same source of Salmonella. © 2015 Blackwell Verlag GmbH.

Development of Rapid Detection and Genetic Characterization of Salmonella in Poultry Breeder Feeds

PubMed Central

Jarquin, Robin; Hanning, Irene; Ahn, Soohyoun; Ricke, Steven C.

2009-01-01

Salmonella is a leading cause of foodborne illness in the United States, with poultry and poultry products being a primary source of infection to humans. Poultry may carry some Salmonella serovars without any signs or symptoms of disease and without causing any adverse effects to the health of the bird. Salmonella may be introduced to a flock by multiple environmental sources, but poultry feed is suspected to be a leading source. Detecting Salmonella in feed can be challenging because low levels of the bacteria may not be recovered using traditional culturing techniques. Numerous detection methodologies have been examined over the years for quantifying Salmonella in feeds and many have proven to be effective for Salmonella isolation and detection in a variety of feeds. However, given the potential need for increased detection sensitivity, molecular detection technologies may the best candidate for developing rapid sensitive methods for identifying small numbers of Salmonella in the background of large volumes of feed. Several studies have been done using polymerase chain reaction (PCR) assays and commercial kits to detect Salmonella spp. in a wide variety of feed sources. In addition, DNA array technology has recently been utilized to track the dissemination of a specific Salmonella serotype in feed mills. This review will discuss the processing of feeds and potential points in the process that may introduce Salmonella contamination to the feed. Detection methods currently used and the need for advances in these methods also will be discussed. Finally, implementation of rapid detection for optimizing control methods to prevent and remove any Salmonella contamination of feeds will be considered. PMID:22346699

EPA worst case water microcosms for testing phage biocontrol of Salmonella.

PubMed

McLaughlin, Michael R; Brooks, John P

2008-01-01

A microplate method was developed as a tool to test phages for their ability to control Salmonella in aqueous environments. The method used EPA (U.S. Environmental Protection Agency) worst case water (WCW) in 96-well plates. The WCW provided a consistent and relatively simple defined turbid aqueous matrix, high in total organic carbon (TOC) and total dissolved salts (TDS), to simulate swine lagoon effluent, without the inconvenience of malodor and confounding effects from other biological factors. The WCW was originally defined to simulate high turbidity and organic matter in water for testing point-of-use filtration devices. Use of WCW to simulate lagoon effluent for phage testing is a new and innovative application of this matrix. Control of physical and chemical parameters (TOC, TDS, turbidity, temperature, and pH) allowed precise evaluation of microbiological parameters (Salmonella and phages). In a typical application, wells containing WCW were loaded with Salmonella enterica susp. enterica serovar Typhimurium (ATCC14028) and treated with phages alone and in cocktail combinations. Mean Salmonella inactivation rates (k, where the lower the value, the greater the inactivation) of phage treatments ranged from -0.32 to -1.60 versus -0.004 for Salmonella controls. Mean log(10) reductions (the lower the value, the greater the reduction) of Salmonella phage treatments were -1.60 for phage PR04-1, -2.14 for phage PR37-96, and -2.14 for both phages in a sequential cocktail, versus -0.08 for Salmonella controls. The WCW microcosm system was an effective tool for evaluating the biocontrol potential of Salmonella phages.

Immunisation of chickens with live Salmonella vaccines - Role of booster vaccination.

PubMed

Methner, U

2018-05-17

It is accepted that booster vaccinations of chickens with live Salmonella vaccines are essential part of vaccinations schemes to induce an effective adaptive immune response. As manufacturer of registered live Salmonella vaccines recommend different times of booster the question raises whether the duration between the first and second immunisation might influence the protective effect against Salmonella exposure. Chickens were immunised with a live Salmonella Enteritidis vaccine on day 1 of age followed by a booster vaccination at different intervals (day 28, 35 or 42 of age) to study the effects on the colonisation and invasion of the Salmonella vaccine strain, the humoral immune response and the efficacy against infection with Salmonella Enteritidis on day 56 of age. Immunisation of all groups resulted in a very effective adaptive immune response and a high degree of protection against severe Salmonella exposure, however, the time of booster had only an unverifiable influence on either the colonisation of the vaccine strain, the development of the humoral immune response or the colonisation of the Salmonella challenge strain. Therefore, the first oral immunisation of the chicks on day 1 of age seems to be of special importance and prerequisite for the development of the effective immune response. A booster immunisation should be carried out, however, the time of booster may vary between week 3 and week 7 of age of the chickens without adversely impact on the efficacy of the adaptive immune response or the protective effects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electrochemical characterization of an immunosensor for Salmonella spp. detection

USDA-ARS?s Scientific Manuscript database

Immunosensors represent a rapid alternative method for diagnosing Salmonella contamination. The objective of this study was to develop and evaluate the performance of an electrochemical immunosensor for the detection of Salmonella spp., the most common foodborne pathogen worldwide. In the immunosens...

Control and monitoring of Salmonella in egg-laying chickens

USDA-ARS?s Scientific Manuscript database

Contaminated eggs have been internationally significant sources for the transmission of Salmonella infection to humans for several decades. Both the public and private sectors have invested substantial resources in comprehensive risk reduction and monitoring programs for Salmonella in commercial egg...

Survival of Salmonella spp. In Waste Egg Wash Water

EPA Science Inventory

The survival of salmonellae under various environmental conditions has been subject of numerous research studies. Due to low densities of these organisms in natural samples, laboratory or clinical cultures were used to ensure that the initial density of salmonellae was sufficien...

Bacteriophage cocktail for biocontrol of Salmonella in dried pet food.

PubMed

Heyse, Serena; Hanna, Leigh Farris; Woolston, Joelle; Sulakvelidze, Alexander; Charbonneau, Duane

2015-01-01

Human salmonellosis has been associated with contaminated pet foods and treats. Therefore, there is interest in identifying novel approaches for reducing the risk of Salmonella contamination within pet food manufacturing environments. The use of lytic bacteriophages shows promise as a safe and effective way to mitigate Salmonella contamination in various food products. Bacteriophages are safe, natural, highly targeted antibacterial agents that specifically kill bacteria and can be targeted to kill food pathogens without affecting other microbiota. In this study, we show that a cocktail containing six bacteriophages had a broadspectrum activity in vitro against a library of 930 Salmonella enterica strains representing 44 known serovars. The cocktail was effective against 95% of the strains in this tested library. In liquid culture dose-ranging experiments, bacteriophage cocktail concentrations of ≥10(8) PFU/ml inactivated more than 90% of the Salmonella population (10(1) to 10(3) CFU/ml). Dried pet food inoculated with a mixture containing equal proportions of Salmonella serovars Enteritidis (ATCC 4931), Montevideo (ATCC 8387), Senftenberg (ATCC 8400), and Typhimurium (ATCC 13311) and then surface treated with the six-bacteriophage cocktail (≥2.5 ± 1.5 × 10(6) PFU/g) achieved a greater than 1-log (P < 0.001) reduction compared with the phosphate-buffered saline-treated control in measured viable Salmonella within 60 min. Moreover, this bacteriophage cocktail reduced natural contamination in samples taken from an undistributed lot of commercial dried dog food that tested positive for Salmonella. Our results indicate that bacteriophage biocontrol of S. enterica in dried pet food is technically feasible.

Characterization of the RpoS Status of Clinical Isolates of Salmonella enterica

PubMed Central

Robbe-Saule, Véronique; Algorta, Gabriela; Rouilhac, Isabelle; Norel, Françoise

2003-01-01

The stationary-phase-inducible sigma factor, σS (RpoS), is the master regulator of the general stress response in Salmonella and is required for virulence in mice. rpoS mutants can frequently be isolated from highly passaged laboratory strains of Salmonella. We examined the rpoS status of 116 human clinical isolates of Salmonella, including 41 Salmonella enterica serotype Typhi strains isolated from blood, 38 S. enterica serotype Typhimurium strains isolated from blood, and 37 Salmonella serotype Typhimurium strains isolated from feces. We examined the abilities of these strains to produce the σS protein, to express RpoS-dependent catalase activity, and to resist to oxidative stress in the stationary phase of growth. We also carried out complementation experiments with a cloned wild-type rpoS gene. Our results showed that 15 of the 41 Salmonella serotype Typhi isolates were defective in RpoS. We sequenced the rpoS allele of 12 strains. This led to identification of small insertions, deletions, and point mutations resulting in premature stop codons or affecting regions 1 and 2 of σS, showing that the rpoS mutations are not clonal. Thus, mutant rpoS alleles can be found in freshly isolated clinical strains of Salmonella serotype Typhi, and they may affect virulence properties. Interestingly however, no rpoS mutants were found among the 75 Salmonella serotype Typhimurium isolates. Strains that differed in catalase activity and resistance to hydrogen peroxide were found, but the differences were not linked to the rpoS status. This suggests that Salmonella serotype Typhimurium rpoS mutants are counterselected because rpoS plays a role in the pathogenesis of Salmonella serotype Typhimurium in humans or in the transmission cycle of the disease. PMID:12902215

Salmonella Questions and Answers

MedlinePlus

... Forms Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District ... Inspection Service (FSIS) of the U.S. Department of Agriculture (USDA) is addressing the problems of Salmonella contamination ...

Antimicrobial resistance and management of invasive Salmonella disease.

PubMed

Kariuki, Samuel; Gordon, Melita A; Feasey, Nicholas; Parry, Christopher M

2015-06-19

Invasive Salmonella infections (typhoidal and non-typhoidal) cause a huge burden of illness estimated at nearly 3.4 million cases and over 600,000 deaths annually especially in resource-limited settings. Invasive non-typhoidal Salmonella (iNTS) infections are particularly important in immunosuppressed populations especially in sub-Saharan Africa, causing a mortality of 20-30% in vulnerable children below 5 years of age. In these settings, where routine surveillance for antimicrobial resistance is rare or non-existent, reports of 50-75% multidrug resistance (MDR) in NTS are common, including strains of NTS also resistant to flouroquinolones and 3rd generation cephalosporins. Typhoid (enteric) fever caused by Salmonella Typhi and Salmonella Paratyphi A remains a major public health problem in many parts of Asia and Africa. Currently over a third of isolates in many endemic areas are MDR, and diminished susceptibility or resistance to fluoroquinolones, the drugs of choice for MDR cases over the last decade is an increasing problem. The situation is particularly worrying in resource-limited settings where the few remaining effective antimicrobials are either unavailable or altogether too expensive to be afforded by either the general public or by public health services. Although the prudent use of effective antimicrobials, improved hygiene and sanitation and the discovery of new antimicrobial agents may offer hope for the management of invasive salmonella infections, it is essential to consider other interventions including the wider use of WHO recommended typhoid vaccines and the acceleration of trials for novel iNTS vaccines. The main objective of this review is to describe existing data on the prevalence and epidemiology of antimicrobial resistant invasive Salmonella infections and how this affects the management of these infections, especially in endemic developing countries. Copyright © 2015. Published by Elsevier Ltd.

Antimicrobial resistance and management of invasive Salmonella disease

PubMed Central

Kariuki, Samuel; Gordon, Melita A.; Feasey, Nicholas; Parry, Christopher M

2015-01-01

Invasive Salmonella infections (typhoidal and non-typhoidal) cause a huge burden of illness estimated at nearly 3.4 million cases and over 600,000 deaths annually especially in resource-limited settings. Invasive non-typhoidal Salmonella (iNTS) infections are particularly important in immunosuppressed populations especially in sub-Saharan Africa, causing a mortality of 20–30% in vulnerable children below 5 years of age. In these settings, where routine surveillance for antimicrobial resistance is rare or non-existent, reports of 50–75% multidrug resistance (MDR) in NTS are common, including strains of NTS also resistant to flouroquinolones and 3rd generation cephalosporins. Typhoid (enteric) fever caused by Salmonella Typhi and Salmonella Paratyphi A remains a major public health problem in many parts of Asia and Africa. Currently over a third of isolates in many endemic areas are MDR, and diminished susceptibility or resistance to fluoroquinolones, the drugs of choice for MDR cases over the last decade is an increasing problem. The situation is particularly worrying in resource-limited settings where the few remaining effective antimicrobials are either unavailable or altogether too expensive to be afforded by either the general public or by public health services. Although the prudent use of effective antimicrobials, improved hygiene and sanitation and the discovery of new antimicrobial agents may offer hope for the management of invasive salmonella infections, it is essential to consider other interventions including the wider use of WHO recommended typhoid vaccines and the acceleration of trials for novel iNTS vaccines. The main objective of this review is to describe existing data on the prevalence and epidemiology of antimicrobial resistant invasive Salmonella infections and how this affects the management of these infections, especially in endemic developing countries. PMID:25912288

Quinolone Resistance Mechanisms Among Salmonella enterica in Malaysia.

PubMed

Thong, Kwai Lin; Ngoi, Soo Tein; Chai, Lay Ching; Teh, Cindy Shuan Ju

2016-06-01

The prevalence of quinolone-resistant Salmonella enterica is on the rise worldwide. Salmonella enterica is one of the major foodborne pathogens in Malaysia. Therefore, we aim to investigate the occurrence and mechanisms of quinolone resistance among Salmonella strains isolated in Malaysia. A total of 283 Salmonella strains isolated from food, humans, and animals were studied. The disk diffusion method was used to examine the quinolone susceptibility of the strains, and the minimum inhibitory concentration (MIC) values of nalidixic acid and ciprofloxacin were also determined. DNA sequencing of the quinolone resistance-determining regions (QRDRs) of gyrase and topoisomerase IV genes and the plasmid-borne qnr genes was performed. The transfer of the qnr gene was examined through transconjugation experiment. A total of 101 nalidixic acid-resistant Salmonella strains were identified. In general, all strains were highly resistant to nalidixic acid (average MICNAL, 170 μg/ml). Resistance to ciprofloxacin was observed in 30.7% of the strains (1 ≤ MICCIP ≤ 2 μg/ml). Majority of the strains contained missense mutations in the QRDR of gyrA (69.3%). Silent mutations were frequently detected in gyrB (75.2%), parC (27.7%), and parE (51.5%) within and beyond the QRDRs. Novel mutations were detected in parC and parE. The plasmid-borne qnrS1 variant was found in 36.6% of the strains, and two strains were found to be able to transfer the qnrS1 gene. Overall, mutations in gyrA and the presence of qnrS1 genes might have contributed to the high level of quinolone resistance among the strains. Our study provided a better understanding on the status of quinolone resistance among Salmonella strains circulating in Malaysia.

Identification and characterization of salmonella serotypes using DNA spectral characteristics by fourier transform infrared (FT-IR) spectroscopy

USDA-ARS?s Scientific Manuscript database

Analysis of DNA samples of Salmonella serotypes (Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg and Salmonella Kentucky) were performed using Fourier transform infrared spectroscopy (FT-IR) spectrometer by placing directly in contact with a diamond attenua...

LAMP-3 (Lysosome-Associated Membrane Protein 3) Promotes the Intracellular Proliferation of Salmonella typhimurium.

PubMed

Lee, Eun-Ju; Park, Kwan-Sik; Jeon, In-Sook; Choi, Jae-Woon; Lee, Sang-Jeon; Choy, Hyun E; Song, Ki-Duk; Lee, Hak-Kyo; Choi, Joong-Kook

2016-07-01

Lysosomes are cellular organelles containing diverse classes of catabolic enzymes that are implicated in diverse cellular processes including phagocytosis, autophagy, lipid transport, and aging. Lysosome-associated membrane proteins (LAMP-1 and LAMP-2) are major glycoproteins important for maintaining lysosomal integrity, pH, and catabolism. LAMP-1 and LAMP-2 are constitutively expressed in Salmonella-infected cells and are recruited to Salmonella-containing vacuoles (SCVs) as well as Salmonella-induced filaments (Sifs) that promote the survival and proliferation of the Salmonella. LAMP-3, also known as DC-LAMP/CD208, is a member of the LAMP family of proteins, but its role during Salmonella infection remains unclear. DNA microarray analysis identified LAMP-3 as one of the genes responding to LPS stimulation in THP-1 macrophage cells. Subsequent analyses reveal that LPS and Salmonella induced the expression of LAMP-3 at both the transcriptional and translational levels. Confocal Super resolution N-SIM imaging revealed that LAMP-3, like LAMP-2, shifts its localization from the cell surface to alongside Salmonella. Knockdown of LAMP-3 by specific siRNAs decreased the number of Salmonella recovered from the infected cells. Therefore, we conclude that LAMP-3 is induced by Salmonella infection and recruited to the Salmonella pathogen for intracellular proliferation.

LAMP-3 (Lysosome-Associated Membrane Protein 3) Promotes the Intracellular Proliferation of Salmonella typhimurium

PubMed Central

Lee, Eun-Ju; Park, Kwan-Sik; Jeon, In-Sook; Choi, Jae-Woon; Lee, Sang-Jeon; Choy, Hyun E.; Song, Ki-Duk; Lee, Hak-Kyo; Choi, Joong-Kook

2016-01-01

Lysosomes are cellular organelles containing diverse classes of catabolic enzymes that are implicated in diverse cellular processes including phagocytosis, autophagy, lipid transport, and aging. Lysosome-associated membrane proteins (LAMP-1 and LAMP-2) are major glycoproteins important for maintaining lysosomal integrity, pH, and catabolism. LAMP-1 and LAMP-2 are constitutively expressed in Salmonella-infected cells and are recruited to Salmonella-containing vacuoles (SCVs) as well as Salmonella-induced filaments (Sifs) that promote the survival and proliferation of the Salmonella. LAMP-3, also known as DC-LAMP/CD208, is a member of the LAMP family of proteins, but its role during Salmonella infection remains unclear. DNA microarray analysis identified LAMP-3 as one of the genes responding to LPS stimulation in THP-1 macrophage cells. Subsequent analyses reveal that LPS and Salmonella induced the expression of LAMP-3 at both the transcriptional and translational levels. Confocal Super resolution N-SIM imaging revealed that LAMP-3, like LAMP-2, shifts its localization from the cell surface to alongside Salmonella. Knockdown of LAMP-3 by specific siRNAs decreased the number of Salmonella recovered from the infected cells. Therefore, we conclude that LAMP-3 is induced by Salmonella infection and recruited to the Salmonella pathogen for intracellular proliferation. PMID:27329040

[Study on simultaneous contamination of Salmonella and Campylobacter in retail chicken carcasses in Beijing].

PubMed

Hu, Yujie; Wang, Yeru; Li, Fengqin

2015-01-01

To elucidate the simultaneous contamination of Salmonella and Campylobacter in retail chicken carcasses in Beijing and to carry out the serological typing of all Salmonella isolates as well as the identification of Campylobacter at the species level. A total of 33 chicken carcasses were collected from Beijing supermarkets and farm's trade markets from May to July. All samples were enumerated for Salmonella and Campylobacter. All Salmonella isolates obtained were further serotyped and Campylobacter were identified at the species level. Totally, 19 samples (19/33, 57.6%) and 5 samples (5/33, 15.2%) were positive for Salmonella with the mean level of 119.4 MPN/100g and Campylobacter with the mean level of 58.6 CFU/g, respectively. In terms of Salmonella, 166 isolates with 14 serotypes were obtained. Salmonella Enteritidis was the most common serovar detected followed by S. Indiana. Serovar diversity was very high in all Salmonella isolates and various Salmonella serovars were detected in the same chicken carcass. A total of 11 serovar distribution spectrums were found and S. Enteritidis in combination with S. Indiana was the predominant. The retail chicken carcasses in Beijing collected from May to July were heavily contaminated by Salmonella with high serovar diversity.

Development of a Salmonella cross-protective vaccine for food animal production systems.

PubMed

Heithoff, Douglas M; House, John K; Thomson, Peter C; Mahan, Michael J

2015-01-01

Intensive livestock production is associated with increased Salmonella exposure, transmission, animal disease, and contamination of food and water supplies. Modified live Salmonella enterica vaccines that lack a functional DNA adenine methylase (Dam) confer cross-protection to a diversity of salmonellae in experimental models of murine, avian, ovine, and bovine models of salmonellosis. However, the commercial success of any vaccine is dependent upon the therapeutic index, the ratio of safety/efficacy. Herein, secondary virulence-attenuating mutations targeted to genes involved in intracellular and/or systemic survival were introduced into Salmonella dam vaccines to screen for vaccine candidates that were safe in the animal and the environment, while maintaining the capacity to confer cross-protective immunity to pathogenic salmonellae serotypes. Salmonella dam mgtC, dam sifA, and dam spvB vaccine strains exhibited significantly improved vaccine safety as evidenced by the failure to give rise to virulent revertants during the infective process, contrary to the parental Salmonella dam vaccine. Further, these vaccines exhibited a low grade persistence in host tissues that was associated with reduced vaccine shedding, reduced environmental persistence, and induction of cross-protective immunity to pathogenic serotypes derived from infected livestock. These data indicate that Salmonella dam double mutant vaccines are suitable for commercial applications against salmonellosis in livestock production systems. Reducing pre-harvest salmonellae load through vaccination will promote the health and productivity of livestock and reduce contamination of livestock-derived food products, while enhancing overall food safety. Copyright © 2014 Elsevier Ltd. All rights reserved.

A rabbit model of non-typhoidal Salmonella bacteremia.

PubMed

Panda, Aruna; Tatarov, Ivan; Masek, Billie Jo; Hardick, Justin; Crusan, Annabelle; Wakefield, Teresa; Carroll, Karen; Yang, Samuel; Hsieh, Yu-Hsiang; Lipsky, Michael M; McLeod, Charles G; Levine, Myron M; Rothman, Richard E; Gaydos, Charlotte A; DeTolla, Louis J

2014-09-01

Bacteremia is an important cause of morbidity and mortality in humans. In this study, we focused on the development of an animal model of bacteremia induced by non-typhoidal Salmonella. New Zealand White rabbits were inoculated with a human isolate of non-typhoidal Salmonella strain CVD J73 via the intra-peritoneal route. Blood samples were collected at specific time points and at euthanasia from infected rabbits. Additionally, tissue samples from the heart, lungs, spleen, gastrointestinal tract, liver and kidneys were obtained at euthanasia. All experimentally infected rabbits displayed clinical signs of disease (fever, dehydration, weight loss and lethargy). Tissues collected at necropsy from the animals exhibited histopathological changes indicative of bacteremia. Non-typhoidal Salmonella bacteria were detected in the blood and tissue samples of infected rabbits by microbiological culture and real-time PCR assays. The development of this animal model of bacteremia could prove to be a useful tool for studying how non-typhoidal Salmonella infections disseminate and spread in humans. Copyright © 2014 Elsevier Ltd. All rights reserved.

Antimicrobial Resistance in Bacterial Poultry Pathogens: A Review

PubMed Central

Nhung, Nguyen Thi; Chansiripornchai, Niwat; Carrique-Mas, Juan J.

2017-01-01

Antimicrobial resistance (AMR) is a global health threat, and antimicrobial usage and AMR in animal production is one of its contributing sources. Poultry is one of the most widespread types of meat consumed worldwide. Poultry flocks are often raised under intensive conditions using large amounts of antimicrobials to prevent and to treat disease, as well as for growth promotion. Antimicrobial resistant poultry pathogens may result in treatment failure, leading to economic losses, but also be a source of resistant bacteria/genes (including zoonotic bacteria) that may represent a risk to human health. Here we reviewed data on AMR in 12 poultry pathogens, including avian pathogenic Escherichia coli (APEC), Salmonella Pullorum/Gallinarum, Pasteurella multocida, Avibacterium paragallinarum, Gallibacterium anatis, Ornitobacterium rhinotracheale (ORT), Bordetella avium, Clostridium perfringens, Mycoplasma spp., Erysipelothrix rhusiopathiae, and Riemerella anatipestifer. A number of studies have demonstrated increases in resistance over time for S. Pullorum/Gallinarum, M. gallisepticum, and G. anatis. Among Enterobacteriaceae, APEC isolates displayed considerably higher levels of AMR compared with S. Pullorum/Gallinarum, with prevalence of resistance over >80% for ampicillin, amoxicillin, tetracycline across studies. Among the Gram-negative, non-Enterobacteriaceae pathogens, ORT had the highest levels of phenotypic resistance with median levels of AMR against co-trimoxazole, enrofloxacin, gentamicin, amoxicillin, and ceftiofur all exceeding 50%. In contrast, levels of resistance among P. multocida isolates were less than 20% for all antimicrobials. The study highlights considerable disparities in methodologies, as well as in criteria for phenotypic antimicrobial susceptibility testing and result interpretation. It is necessary to increase efforts to harmonize testing practices, and to promote free access to data on AMR in order to improve treatment guidelines as well as to

Salmonella modulation of host cell gene expression promotes its intracellular growth.

PubMed

Hannemann, Sebastian; Gao, Beile; Galán, Jorge E

2013-01-01

Salmonella Typhimurium has evolved a complex functional interface with its host cell largely determined by two type III secretion systems (T3SS), which through the delivery of bacterial effector proteins modulate a variety of cellular processes. We show here that Salmonella Typhimurium infection of epithelial cells results in a profound transcriptional reprogramming that changes over time. This response is triggered by Salmonella T3SS effector proteins, which stimulate unique signal transduction pathways leading to STAT3 activation. We found that the Salmonella-stimulated changes in host cell gene expression are required for the formation of its specialized vesicular compartment that is permissive for its intracellular replication. This study uncovers a cell-autonomous process required for Salmonella pathogenesis potentially opening up new avenues for the development of anti-infective strategies that target relevant host pathways.

[Use of bacteriphages against Salmonella Enteritidis: a prevention tool].

PubMed

García, Cristina; Marín, Clara; Catalá-Gregori, Pablo; Soriano, Jose Miguel

2015-06-01

Salmonellosis is a highly prevalent disease still searching for preventive tools to avoid contamination level priority public health. The in vitro effect of bacteriophages against Salmonella enteritidis was evaluated as a prevention tool. Two tests with three concentrations of bacteriophages were conducted against two strains of Salmonella Enteritidis inoculated in fresh faeces of laying hens. Each test had a positive control. Thus, four groups in each test were evaluated. Each experimental group included two replicates, and three plates were incubated per replicate. The concentrations tested were three: commercial solution (5 × 10(7) pfu/mL), and two dilutions (1/10 and 1/30). One of the strains tested was CECT 4300, a certified strain of Colección Española de Cultivo Tipo and the other a field isolated strain in a sacrificed hen farm. Both strains were inoculated at 1.3 × 10(5) cfu/g of faeces in each of the four groups. Isolation and identification of bacteria by ISO6579 was done at various times after inoculation: 1 minute, 24 hours and 7 days. In the first test, with certified strain, Salmonella was isolated in all groups at time 1 minute. After 24 hours, Salmonella was isolated in all groups except in one of the replicas treated with 1/10 dilution of bacteriophages, one of the other replica plate treated with 1/10 dilution, and two plates of the two replicas treated with the commercial solution. After 7 days, the bacteria were not isolated from any of the experimental groups. In the second test, with the field strain, Salmonella was isolated in all groups at time 1 minute. After 24 hours, Salmonella was isolated in all groups except in one of the replicas treated with 1/10 dilution of bacteriophages and the two replicas treated with the commercial solution. Salmonella was not isolated in any of the experimental groups at 7 days. The use of bacteriophages reduced Salmonella enteritidis isolates in faeces at 24 hours after the application, so it could be

Prevalence and molecular profiles of Salmonella collected at a commercial turkey processing plant.

PubMed

Nde, Chantal W; Sherwood, Julie S; Doetkott, Curt; Logue, Catherine M

2006-08-01

In this study, whole carcasses were sampled at eight stages on a turkey-processing line and Salmonella prevalence was determined using enrichment techniques. Recovered Salmonella was further characterized using serotyping and the molecular profiles were determined using pulsed-field gel electrophoresis (PFGE). Prevalence data showed that contamination rates varied along the line and were greatest after defeathering and after chilling. Analysis of contamination in relation to serotypes and PFGE profiles found that on some visits the same serotype was present all along the processing line while on other days, additional serotypes were recovered that were not detected earlier on the line, suggesting that the birds harbored more than one serotype of Salmonella or there was cross-contamination occurring during processing. Overall, this study found fluctuations in Salmonella prevalence along a turkey-processing line. Following washing, Salmonella prevalence was significantly reduced, suggesting that washing is critical for Salmonella control in turkey processing and has significant application for controlling Salmonella at the postdefeathering and prechill stages where prevalence increased.

76 FR 81513 - Guidance for Industry: Prevention of Salmonella

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-28

...] Guidance for Industry: Prevention of Salmonella Enteritidis in Shell Eggs During Production, Storage, and... ``Prevention of Salmonella Enteritidis in Shell Eggs During Production, Storage, and Transportation.'' The document provides guidance to egg producers on how to comply with certain provisions contained in FDA's...

Differences in carbon source utilization of Salmonella Oranienburg and Saintpaul isolated from river water.

PubMed

Medrano-Félix, Andrés; Estrada-Acosta, Mitzi; Peraza-Garay, Felipe; Castro-Del Campo, Nohelia; Martínez-Urtaza, Jaime; Chaidez, Cristóbal

2017-08-01

Long-term exposure to river water by non-indigenous micro-organisms such as Salmonella may affect metabolic adaptation to carbon sources. This study was conducted to determine differences in carbon source utilization of Salmonella Oranienburg and Salmonella Saintpaul (isolated from tropical river water) as well as the control strain Salmonella Typhimurium exposed to laboratory, river water, and host cells (Hep-2 cell line) growth conditions. Results showed that Salmonella Oranienburg and Salmonella Saintpaul showed better ability for carbon source utilization under the three growth conditions evaluated; however, S. Oranienburg showed the fastest and highest utilization on different carbon sources, including D-Glucosaminic acid, N-acetyl-D-Glucosamine, Glucose-1-phosphate, and D-Galactonic acid, while Salmonella Saintpaul and S. Typhimurium showed a limited utilization of carbon sources. In conclusion, this study suggests that environmental Salmonella strains show better survival and preconditioning abilities to external environments than the control strain based on their plasticity on diverse carbon sources use.

Specialized Transducing Phages Derived from Salmonella Phage P22

PubMed Central

Hoppe, Ingrid; Roth, John

1974-01-01

Salmonella phage P22 has been used in the construction of three sorts of specialized transducing phage: P22 proAB, P22 proABlac and P22 argF. The bacterial genes carried are derived from E. coli K12. Since E. coli and Salmonella chromosomes recombine very poorly, E. coli genes cannot be transduced into Salmonella recipients by P22's generalized transduction mechanism. Therefore, stable inheritance of E. coli material provides a means of detecting specialized transduction. Formation of these phages was possible because the P22 prophage recognizes an attachment site in the E. coli F' prolac episome. Salmonella strains carrying the F' prolac episome can be lysogenized by P22 so as to leave the prophage inserted into the E. coli material of the F' factor. Improper prophage excision can then lead to formation of P22 specialized phages carrying E. coli genetic material. PMID:4599252

Prevalence and antimicrobial resistance pattern of Salmonella in animal feed produced in Namibia.

PubMed

Shilangale, Renatus P; Di Giannatale, Elisabetta; Chimwamurombe, Percy M; Kaaya, Godwin P

2012-01-01

The occurrence of Salmonella is a global challenge in the public health and food production sectors. Our study investigated the prevalence, serovar and antimicrobial susceptibility of strains of Salmonella serovars isolated from animal feed (meat-and-bone and blood meal) samples from two commercial abattoirs in Namibia. A total of 650 samples (n=650) were examined for the presence of Salmonella. Results showed that 10.9% (n=71) were positive for Salmonella. Of the Salmonella serovars isolated, S. Chester was the most commonly isolated serovar (19.7%), followed by S. Schwarzengrund at 12.7%. From the Salmonella isolates, 19.7% (n=14) were resistant to one or more of the antimicrobials (nalidixic acid, trimethoprim-sulfamethoxazole, sulfisoxazole, streptomycin and/or tetracycline), whereas 80.3% (n=57) were susceptible to all 16 antimicrobials tested. Resistance to sulfisoxazole and the trimethroprimsuflamethoxazole combination were the most common. The resistant isolates belonged to ten different Salmonella serovars. The susceptibility of most of the Salmonella isolated to the antimicrobials tested indicates that anti-microbial resistance is not as common and extensive in Namibia as has been reported in many other countries. It also appears that there is a range of antimicrobials available that are effective in managing Salmonella infections in Namibia. However, there is some evidence that resistance is developing and this will need further monitoring to ensure it does not become a problem.

Camel as a transboundary vector for emerging exotic Salmonella serovars.

PubMed

Ghoneim, Nahed H; Abdel-Moein, Khaled A; Zaher, Hala

2017-05-01

The current study was conducted to shed light on the role of imported camels as a transboundary vector for emerging exotic Salmonella serovars. Fecal samples were collected from 206 camels directly after slaughtering including 25 local camels and 181 imported ones as well as stool specimens were obtained from 50 slaughterhouse workers at the same abattoir. The obtained samples were cultured while Salmonella serovars were identified through Gram's stain films, biochemical tests and serotyping with antisera kit. Moreover, the obtained Salmonella serovars were examined by PCR for the presence of invA and stn genes. The overall prevalence of Salmonella serovars among the examined camels was 8.3%. Stn gene was detected in the vast majority of exotic strains (11/14) 78.6% including emerging serovars such as Salmonella Saintpaul, S. Chester, S. Typhimurium whereas only one isolate from local camels carried stn gene (1/3) 33.3%. On the other hand, none of the examined humans yielded positive result. Our findings highlight the potential role of imported camels as a transboundary vector for exotic emerging Salomenella serovars.

[Protagonists of innate immunity during in Salmonella infections].

PubMed

Salez, Laurent; Malo, Danielle

2004-12-01

Salmonella are facultative intracellular Gram-negative bacteria that are found ubiquitously in nature and have the ability to infect a wide range of hosts including humans, domesticated, wild mammals, and birds. The principal clinical manifestations associated with Salmonella infection in humans are enteric fever (typhoid and paratyphoid) and a self-limiting gastroenteritis (salmonellosis). Additionally, silent carriage of this bacterium is frequent and contributes to disease dissemination. Typhoid fever still represents a major public health problem in many developing countries. On the other hand, industrialized countries experience an increased incidence of nontyphoidal Salmonella infections with most cases tracing back to food contamination. Studies using mouse model of infection with a highly virulent Salmonella typhimurium serotype have provided important insight into the complexity of the innate immune response to infection. The players are numerous but emphasis was placed on the genes that were discovered using genetic approaches and in vivo assay with live pathogen and include positional cloning of mouse mutations and manipulation of genes in the context of whole animal either by transgenesis or knockout technologies. Some of the critical genes include those known to play a role in the detection of the bacteria (Cd14, Lbp, Tlr4 and Tlr5) and in microbicidal activity (Slc11a1, Nos2, NADPH oxidase and cryptdins). These discoveries have already initiated the search for the contribution of particular genetic pathways in the innate immune response of humans to infection with Salmonella and other intracellular microorganisms.

Persistence of poultry associated Salmonella spp. on spinach plants

USDA-ARS?s Scientific Manuscript database

Introduction: Pre-harvest spinach contamination can occur via irrigation water and can influence the persistence of Salmonella on spinach leaves. Salmonella persistence on spinach plants should be evaluated as nearby poultry farms can be a critical source of contaminated water run-off. Purpose: The...

Nano-materials for use in sensing of salmonella infections: Recent advances.

PubMed

Pashazadeh, Paria; Mokhtarzadeh, Ahad; Hasanzadeh, Mohammad; Hejazi, Maryam; Hashemi, Maryam; de la Guardia, Miguel

2017-01-15

Salmonella infectious diseases spreading every day through food have become a life-threatening problem for millions of people and growing menace to society. Health expert's estimate that the yearly cost of all the food borne diseases is approximately $5-6 billion. Traditional methodologies for salmonella analysis provide high reliability and very low limits of detection. Among them immunoassays and Nucleic acid-based assays provide results within 24h, but they are expensive, tedious and time consuming. So, there is an urgent need for development of rapid, robust and cost-effective alternative technologies for real-time monitoring of salmonella. Several biosensors have been designed and commercialized for detection of this pathogen in food and water. In this overview, we have updated the literature concerning novel biosensing methods such as various optical and electrochemical biosensors and newly developed nano- and micro-scaled and aptamers based biosensors for detection of salmonella pathogen. Furthermore, attention has been focused on the principal concepts, applications, and examples that have been achieved up to diagnose salmonella. In addition, commercial biosensors and foreseeable future trends for onsite detecting salmonella have been summarized. Copyright © 2016 Elsevier B.V. All rights reserved.

Advanced Oxidation Process sanitization of hatching eggs reduces Salmonella in broiler chicks.

PubMed

Rehkopf, A C; Byrd, J A; Coufal, C D; Duong, T

2017-10-01

The microbial quality of eggs entering the hatchery is an important critical control point for biosecurity, pathogen reduction, and food safety programs in poultry production. Developing interventions to reduce Salmonella contamination of eggs is important to improving the microbial food safety of poultry and poultry products. The hydrogen peroxide (H2O2) and ultraviolet light (UV) Advanced Oxidation Process (AOP) has been previously demonstrated to be effective in reducing Salmonella on the surface of experimentally contaminated eggs. The objective of this study was to evaluate the effect of treating eggs with an egg-sanitizing apparatus using the H2O2/UV AOP on Salmonella contamination during incubation, hatching, and in broiler chicks during grow-out. Experimentally contaminated eggs were treated using the automated H2O2/UV AOP egg sanitizer and incubated for 21 d. AOP sanitization reduced Salmonella up to 7 log10 cfu egg-1 (P < 0.05) from the surface of experimentally contaminated eggs and reduced the number of Salmonella positive eggs by up to 75% (P < 0.05) when treated 1 h post-inoculation. AOP treatment also reduced the number of Salmonella-positive eggs during incubation. Additionally, Salmonella was recovered from more chicks hatched from untreated eggs than from eggs treated using the H2O2/UV AOP egg sanitizer (P < 0.05) through 14 d posthatch. These data suggest reduction of Salmonella contamination on the surface of eggs using the H2O2/UV AOP egg sanitizer prior to incubation may reduce the gastrointestinal colonization of chicks by Salmonella. © 2017 Poultry Science Association Inc.

Foodborne Salmonella-caused outbreaks in Catalonia (Spain), 1990 to 2003.

PubMed

Domínguez, Angela; Torner, Nuria; Ruiz, Laura; Martínez, Ana; Bartolomé, Rosa; Sulleiro, Elena; Teixidó, Angel; Plasencia, Antoni

2007-01-01

In most developed countries, nontyphoid Salmonella is an important cause of sporadic cases and outbreaks of foodborne gastroenteritis. The aim of this study was to investigate the trend of foodborne Salmonella-caused outbreaks and number of cases, hospitalizations, and deaths and compare them with those caused by other infectious agents. The study was carried out in Catalonia, a region in northeastern Spain with a population of 6.5 million inhabitants, in 2002. All information on reported outbreaks of foodborne disease from 1990 to 2003 was reviewed. For each outbreak, the following variables were collected: year; setting (household, restaurant, school, hospital, nursing home, and others); number of cases, hospitalizations, and deaths; causal agent; and food vehicle involved. Of 1652 reported outbreaks, 1078 had a known causal agent. Among them, 871 (80.8%) were caused by Salmonella, with 14,695 cases, 1534 hospitalizations, and 4 deaths. The rate of hospitalization was higher in outbreaks due to Salmonella than in those caused by other infectious agents (rate ratio, 2.54; 95% confidence interval, 2.20 to 2.94). Forty-eight percent of Salmonella-caused outbreaks were eggborne, compared with 5.3% of those caused by other infectious agents (rate ratio, 1.40; 95% confidence interval, 1.33 to 1.48). The annual number of cases in household outbreaks of eggborne Salmonella rose over time (R2 = 0.82), but the number of outbreaks produced in other settings did not. Eggborne outbreaks caused by Salmonella in households are a major cause of disease, and increased preventive efforts are necessary, especially consumer education and awareness of the risk of eating food containing raw or slightly cooked eggs.

Effect of farm type on within-herd Salmonella prevalence, serovar distribution, and antimicrobial resistance.

PubMed

Rasschaert, G; Michiels, J; Arijs, D; Wildemauwe, C; De Smet, S; Heyndrickx, M

2012-05-01

Salmonella represents a major challenge to the pig industry, as pork presents a risk for human salmonellosis. In this study, we have examined the effect of farm type on the prevalence of fattening pigs shedding Salmonella on 12 farms at risk for harboring Salmonella. On six open (grow-to-finish) and six closed (farrow-to-finish) farms, the prevalence of pigs shedding Salmonella was determined on two occasions approximately 2 months apart. The serovar, phage type, and antimicrobial resistance of the obtained Salmonella isolates were determined. On all farms, pigs shedding Salmonella were detected on at least one of the two sampling days. The mean within-herd prevalence was 7.8%. Closed farms were two times less likely to have pigs shedding Salmonella than open farms. On open farms, the odds of finding Salmonella shedding in pigs were 1.9 times higher when sampling was performed at slaughter age than when samples were taken halfway through the fattening period. Salmonella enterica serovar Typhimurium was the most predominant serotype, with a prevalence of 62 to 63% on both farm types. Of all the Salmonella Typhimurium isolates, 65% had the tetraresistant profile ASSuT (ampicillin, streptomycin, sulfonamide, and tetracycline) with or without additional resistance to trimethoprim-sulfonamide. Phage type DT120 seemed to be especially associated with this antimicrobial-resistant profile. The prevalence of Salmonella Typhimurium isolates showing resistance to ampicillin, streptomycin, tetracycline, sulfonamide, trimethoprim-sulfonamide, and lincomycin hydrochloride and spectinomycin sulfate tetrahydrate was significantly higher on open farms than on closed farms.

Enjoying Homemade Ice Cream without the Risk of Salmonella Infection

MedlinePlus

... Contaminants Buy, Store & Serve Safe Food Enjoying Homemade Ice Cream without the Risk of Salmonella Infection Share ... it Email Print August 2004 Every year homemade ice cream causes several outbreaks of Salmonella infection with ...

Split marketing as a risk factor for Salmonella enterica infection in swine.

PubMed

Rostagno, Marcos H; Hurd, H Scott; McKean, James D

2009-09-01

On-farm reduction of Salmonella carriage prevalence in pigs requires the identification of risk factors to direct interventions development. This study was designed to determine if split marketing of finishing pigs constitutes a risk factor for Salmonella infections, by comparing Salmonella prevalence in the first group of pigs selected for harvest ("first pull") versus the prevalence in the last group of pigs selected for harvest ("close out") from multiple commercial finishing lots. Nine paired samplings were conducted consisting in matched groups of pigs from individual barns as the first pull and the close out with a 4-week interval between groups. From each group, fecal and meat samples were collected, on-farm and at harvest, respectively. Fecal samples were selectively enriched, and analyzed for the presence of Salmonella, whereas meat juice samples were analyzed for the presence of antibodies against Salmonella. In 7/9 (77.8%) of the studied barns, an increase in Salmonella prevalence was observed, based on both bacteriologic and serologic analysis. Overall, there was an increase of 9.2% (p < 0.05) in bacteriologic prevalence, and 31.3% (p < 0.05) in serologic prevalence from first pull to close out groups. This study demonstrates that a significant increase in Salmonella prevalence occurs between the first and the last group of pigs harvested from finishing lots, with close out groups of market pigs posing a higher risk for Salmonella contaminations.

Age-Dependent Enterocyte Invasion and Microcolony Formation by Salmonella

PubMed Central

Zhang, Kaiyi; Dupont, Aline; Torow, Natalia; Gohde, Fredrik; Leschner, Sara; Lienenklaus, Stefan; Weiss, Siegfried; Brinkmann, Melanie M.; Kühnel, Mark; Hensel, Michael; Fulde, Marcus; Hornef, Mathias W.

2014-01-01

The coordinated action of a variety of virulence factors allows Salmonella enterica to invade epithelial cells and penetrate the mucosal barrier. The influence of the age-dependent maturation of the mucosal barrier for microbial pathogenesis has not been investigated. Here, we analyzed Salmonella infection of neonate mice after oral administration. In contrast to the situation in adult animals, we observed spontaneous colonization, massive invasion of enteroabsorptive cells, intraepithelial proliferation and the formation of large intraepithelial microcolonies. Mucosal translocation was dependent on enterocyte invasion in neonates in the absence of microfold (M) cells. It further resulted in potent innate immune stimulation in the absence of pronounced neutrophil-dominated pathology. Our results identify factors of age-dependent host susceptibility and provide important insight in the early steps of Salmonella infection in vivo. We also present a new small animal model amenable to genetic manipulation of the host for the analysis of the Salmonella enterocyte interaction in vivo. PMID:25210785

Animal Salmonella surveillance in Peninsular Malaysia, 1981-1985.

PubMed Central

Joseph, P. G.; Sivanandan, S. P.; Yee, H. T.

1988-01-01

During the 5-year (1981-5) surveillance period, 2322 salmonella isolations were recorded from animals and other non-human sources in Peninsular Malaysia. This was an increase of 356% over the preceding 5-year period. The 83 serotypes isolated were recovered from 41 sources. Of these 34 were new serotypes bringing the total number of serotypes isolated from non-human sources to date up 97. Food animals and edible animal products accounted for 92.2% of the total isolations, with cattle and beef accounting for 70% of the total. Salmonella dublin was the most frequently isolated serotype, whereas S. typhimurium had the widest zoological distribution. More than 80% of the non-human salmonella serotypes have also been reported in man in this country. PMID:3378581

Improving Salmonella determination in Sinaloa rivers with ultrafiltration and most probable number methods.

PubMed

Jimenez, Maribel; Chaidez, Cristobal

2012-07-01

Monitoring of waterborne pathogens is improved by using concentration methods prior to detection; however, direct microbial enumeration is desired to study microbial ecology and human health risks. The aim of this work was to determine Salmonella presence in river water with an ultrafiltration system coupled with the ISO 6579:1993 isolation standard method (UFS-ISO). Most probable number (MPN) method was used directly in water samples to estimate Salmonella populations. Additionally, the effect between Salmonella determination and water turbidity was evaluated. Ten liters or three tenfold dilutions (1, 0.1, and 0.01 mL) of water were processed for Salmonella detection and estimation by the UFS-ISO and MPN methods, respectively. A total of 84 water samples were tested, and Salmonella was confirmed in 64/84 (76%) and 38/84 (44%) when UFS-ISO and MPN were used, respectively. Salmonella populations were less than 5 × 10(3) MPN/L in 73/84 of samples evaluated (87%), and only three (3.5%) showed contamination with numbers greater than 4.5 × 10(4) MPN/L. Water turbidity did not affect Salmonella determination regardless of the performed method. These findings suggest that Salmonella abundance in Sinaloa rivers is not a health risk for human infections in spite of its persistence. Thus, choosing the appropriate strategy to study Salmonella in river water samples is necessary to clarify its behavior and transport in the environment.

Prevalence, molecular and antimicrobial resistance of Salmonella isolated from sausages in Meknes, Morocco.

PubMed

Ed-Dra, Abdelaziz; Filali, Fouzia Rhazi; Karraouan, Bouchra; El Allaoui, Abdellah; Aboulkacem, Amal; Bouchrif, Brahim

2017-04-01

Salmonella is among the most important food borne pathogens worldwide contaminating a wide range of animal products including meat products. The aims of this study go through two steps: The first step is to estimate the proportion of sausages products contaminated with Salmonella in Meknes city (Morocco), which were collected from various shopping sites: butchery, street vendors, supermarket and souk (Weekly market combines the population of the small villages around Meknes city). The second one is to identify serovars, to determine the antimicrobials resistance patterns of isolates and to detect the invA and spvC genes. 34 (21.79%) Salmonella were isolated, recovered 4 serogroups and 12 serotypes. The most prevalent serotypes were Salmonella Corvallis (23.53%) and Salmonella Kentucky (17.65%). All Salmonella isolates were tested for their susceptibility to 18 selected antimicrobials agents, of which 100% were resistant to at least one antimicrobial, 85.30% (29/34) were resistant to two or more antimicrobials and 44.12% (15/34) were resistant to at least three antimicrobials. All Salmonella are resistant to ampicillin, 76.47% to streptomycin, 20.59% to sulfonamides, 17.65% to Tetracycline and 11.77% to Ofloxacin. The "ACSSuT" penta-resistance pattern was observed in tow of the Salmonella Typhimurium strains. In addition, this study showed that all Salmonella strains (34) were positive for invasion gene invA and negative for the virulence gene spvC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Disinfectant susceptibility of different Salmonella serotypes isolated from chicken and egg production chains.

PubMed

Long, M; Lai, H; Deng, W; Zhou, K; Li, B; Liu, S; Fan, L; Wang, H; Zou, L

2016-09-01

The study aimed to serotype the Salmonella isolates recovered from chicken and egg production chains, and to investigate the disinfectant resistance phenotypes and genotypes of these isolates. The Salmonella isolates were serotyped, and the minimal inhibitory concentrations (MICs) of disinfectants were determined. Results showed that the Salmonella isolates recovered from both chains were diverse, and the serotypes in each part of the production chain and between the two production chains were significantly different. In the chicken production chain, 19 different serotypes were recovered, while only five serotypes were found in the egg production chain. The isolates showed a high susceptibility to didecyldimethylammonium bromide (DDAB) but a low susceptibility to benzalkonium chloride (BC), benzalkonium bromide (BAB) and chlorhexidine (CHX). Salmonella Enteritidis and Salmonella Typhimurium were more resistant to BC and BAB. The qacEΔ1 and qacF resistance genes were detected in 26·7 and 7·7% of the isolates respectively. The qacEΔ1 gene was frequently found in Salmonella Derby and Salm. Enteritidis (P < 0·05). Our findings indicated that Salmonella was commonly present in both chains, and could serve as a critical vector in spreading disinfectant resistance associated with different serotypes. This study first demonstrated disinfectant resistance phenotypes and genotypes of serotyped Salmonella. The study highlights the need for monitoring the disinfectant resistance varied in different Salmonella serotypes. © 2016 The Society for Applied Microbiology.

Predicting Salmonella populations from biological, chemical, and physical indicators in Florida surface waters.

PubMed

McEgan, Rachel; Mootian, Gabriel; Goodridge, Lawrence D; Schaffner, Donald W; Danyluk, Michelle D

2013-07-01

Coliforms, Escherichia coli, and various physicochemical water characteristics have been suggested as indicators of microbial water quality or index organisms for pathogen populations. The relationship between the presence and/or concentration of Salmonella and biological, physical, or chemical indicators in Central Florida surface water samples over 12 consecutive months was explored. Samples were taken monthly for 12 months from 18 locations throughout Central Florida (n = 202). Air and water temperature, pH, oxidation-reduction potential (ORP), turbidity, and conductivity were measured. Weather data were obtained from nearby weather stations. Aerobic plate counts and most probable numbers (MPN) for Salmonella, E. coli, and coliforms were performed. Weak linear relationships existed between biological indicators (E. coli/coliforms) and Salmonella levels (R(2) < 0.1) and between physicochemical indicators and Salmonella levels (R(2) < 0.1). The average rainfall (previous day, week, and month) before sampling did not correlate well with bacterial levels. Logistic regression analysis showed that E. coli concentration can predict the probability of enumerating selected Salmonella levels. The lack of good correlations between biological indicators and Salmonella levels and between physicochemical indicators and Salmonella levels shows that the relationship between pathogens and indicators is complex. However, Escherichia coli provides a reasonable way to predict Salmonella levels in Central Florida surface water through logistic regression.

Prevalence of Salmonella spp. in environmental samples from table egg barns in Alberta.

PubMed

St Amand, Joan A; Cassis, Rashed; King, Robin K; Annett Christianson, Colleen B

2017-12-01

Some Salmonella spp. are zoonotic, a frequent cause of foodborne illness in Canada, and known to infect humans through contaminated poultry and poultry products. Certain serotypes of Salmonella spp. have been demonstrated to be vertically transmitted from hen to egg. The incidence of Salmonella spp. isolation in the flock has been correlated to its isolation from the environment. Twenty-one producers were enrolled in this study to examine the occurrence of Salmonella spp. in 48 table egg layer flocks housed in 35 barns in Alberta. The purpose of this study was to: (i) identify Salmonella serotypes isolated from the environment of table egg layer facilities in Alberta and (ii) record the prevalence of Salmonella spp. across eight defined environmental sampling points. Salmonella spp. were isolated from the environment of 20/35 barns representing 29/48 flocks. The most common serotypes isolated were S. Heidelberg, S. Kentucky and S. Mbandaka. The order of most to least contaminated sample location was manure belts (54.1%), feeders (47.9%), feed motors (45.8%), egg belts and walls (41.7%), fans (35.0%), cage bottoms (31.3%) and lobbies (27.1%). Salmonella spp. were isolated from 7/7 barns post cleaning and disinfection, demonstrating the persistence of this organism in the environment and the need for effective eradication protocols.

Antimicrobial resistance among Salmonella enterica serovar Infantis from broiler carcasses in Serbia

NASA Astrophysics Data System (ADS)

Nikolić, A.; Baltić, T.; Velebit, B.; Babić, M.; Milojević, L.; Đorđević, V.

2017-09-01

This study aimed to investigate antimicrobial resistance of Salmonella Infantis isolates from poultry carcasses in Serbia. A total of 48 Salmonella isolates were examined for antimicrobial resistance. A panel of 10 antibiotics was selected for testing. Isolates showed resistance to sulfamethoxazole, ceftazidime and cefotaxime (100%). However, the highest number of Salmonella Infantis isolates were sensitive to chloramphenicol. The usage of antibiotics in food producing animals could result in antimicrobial resistance pathogenic bacteria especially Salmonella spp. in poultry, which may be transmitted to humans through the food chain and increase risk of treatment failures.

Prevalence and antibiogram study of Salmonella and Staphylococcus aureus in poultry meat

PubMed Central

Akbar, Ali; Anal, Anil Kumar

2013-01-01

Objective To evaluate the presence and antibiogram pattern of Salmonella and Staphylococcus aureus (S. aureus) in retail poultry meat products. Methods Foodborne pathogens (Salmonella and S. aureus) were isolated from poultry meat and confirmed with the help of biochemical and immunological test. Antibiogram of the isolates were examined by following CLSI methods. Results A total number of 209 poultry meat samples were collected and studied in this study. Out of which, 5.26% were found contaminated with Salmonella while 18.18% were found contaminated with S. aureus. All the Salmonella and S. aureus isolates were found resistant to at least one antibiotic. About 72.72% of the Salmonella isolates showed resistance to tetracycline, while S. aureus isolates were also found highly resistant to tetracycline equal to 44.73%. One of the Salmonella isolates showed multi-drug resistance to almost six antibiotics out of nine antibiotics used in the study. Multidrug resistant S. aureus isolates were also found in the study. Conclusions The study confirmed the presence of Salmonella and S. aureus in retail poultry meat. It is a potential threat to consumer health. To reduce the risk of contamination, good hygiene practices are necessary from processing to storage. PMID:23593598

Ability of Cecal Cultures to Inhibit Growth of Salmonella Typhimurium during Aerobic Incubation

USDA-ARS?s Scientific Manuscript database

Introduction: Poultry can serve as reservoirs for Salmonella; however, chicks provided cultures of cecal bacteria develop resistance to colonization by Salmonella. Research has indicated that cecal bacteria metabolize organic acids to produce substances that inhibit Salmonella growth. Purpose: The...

Qualitative map of Salmonella contamination on the chicken carcass

USDA-ARS?s Scientific Manuscript database

Salmonella contamination of poultry is a global public health problem. The objective of this study was to map the distribution of Salmonella on the chicken carcass for the purpose of improving poultry inspection and food safety. Young chickens (n = 70) in the Cornish game hen class were obtained a...

Reveal Salmonella 2.0 test for detection of Salmonella spp. in foods and environmental samples. Performance Tested Method 960801.

PubMed

Hoerner, Rebecca; Feldpausch, Jill; Gray, R Lucas; Curry, Stephanie; Islam, Zahidul; Goldy, Tim; Klein, Frank; Tadese, Theodros; Rice, Jennifer; Mozola, Mark

2011-01-01

Reveal Salmonella 2.0 is an improved version of the original Reveal Salmonella lateral flow immunoassay and is applicable to the detection of Salmonella enterica serogroups A-E in a variety of food and environmental samples. A Performance Tested Method validation study was conducted to compare performance of the Reveal 2.0 method with that of the U.S. Department of Agriculture-Food Safety and Inspection Service or U.S. Food and Drug Administration/Bacteriological Analytical Manual reference culture methods for detection of Salmonella spp. in chicken carcass rinse, raw ground turkey, raw ground beef, hot dogs, raw shrimp, a ready-to-eat meal product, dry pet food, ice cream, spinach, cantaloupe, peanut butter, stainless steel surface, and sprout irrigation water. In a total of 17 trials performed internally and four trials performed in an independent laboratory, there were no statistically significant differences in performance of the Reveal 2.0 and reference culture procedures as determined by Chi-square analysis, with the exception of one trial with stainless steel surface and one trial with sprout irrigation water where there were significantly more positive results by the Reveal 2.0 method. Considering all data generated in testing food samples using enrichment procedures specifically designed for the Reveal method, overall sensitivity of the Reveal method relative to the reference culture methods was 99%. In testing environmental samples, sensitivity of the Reveal method relative to the reference culture method was 164%. For select foods, use of the Reveal test in conjunction with reference method enrichment resulted in overall sensitivity of 92%. There were no unconfirmed positive results on uninoculated control samples in any trials for specificity of 100%. In inclusivity testing, 102 different Salmonella serovars belonging to serogroups A-E were tested and 99 were consistently positive in the Reveal test. In exclusivity testing of 33 strains of non-salmonellae

O-Serotype Conversion in Salmonella Typhimurium Induces Protective Immune Responses against Invasive Non-Typhoidal Salmonella Infections.

PubMed

Li, Pei; Liu, Qing; Luo, Hongyan; Liang, Kang; Yi, Jie; Luo, Ying; Hu, Yunlong; Han, Yue; Kong, Qingke

2017-01-01

Salmonella infections remain a big problem worldwide, causing enteric fever by Salmonella Typhi (or Paratyphi) or self-limiting gastroenteritis by non-typhoidal Salmonella (NTS) in healthy individuals. NTS may become invasive and cause septicemia in elderly or immuno-compromised individuals, leading to high mortality and morbidity. No vaccines are currently available for preventing NTS infection in human. As these invasive NTS are restricted to several O-antigen serogroups including B1, D1, C1, and C2, O-antigen polysaccharide is believed to be a good target for vaccine development. In this study, a strategy of O-serotype conversion was investigated to develop live attenuated S . Typhimurium vaccines against the major serovars of NTS infections. The immunodominant O4 serotype of S . Typhimurium was converted into O9, O7, and O8 serotypes through unmarked chromosomal deletion-insertion mutations. O-serotype conversion was confirmed by LPS silver staining and western blotting. All O-serotype conversion mutations were successfully introduced into the live attenuated S . Typhimurium vaccine S738 (Δ crp Δ cya ) to evaluate their immunogenicity in mice model. The vaccine candidates induced high amounts of heterologous O-polysaccharide-specific functional IgG responses. Vaccinated mice survived a challenge of 100 times the 50% lethality dose (LD 50 ) of wild-type S . Typhimurium. Protective efficacy against heterologous virulent Salmonella challenges was highly O-serotype related. Furthermore, broad-spectrum protection against S . Typhimurium, S . Enteritidis, and S . Choleraesuis was observed by co-vaccination of O9 and O7 O-serotype-converted vaccine candidates. This study highlights the strategy of expressing heterologous O-polysaccharides via genetic engineering in developing live attenuated S . Typhimurium vaccines against NTS infections.

Modeling the survival of Salmonella Enteritidis and Salmonella Typhimurium during the fermentation of yogurt.

PubMed

Savran, Derya; Pérez-Rodríguez, Fernando; Halkman, A Kadir

2018-03-01

The objective of this study was to evaluate the behavior of Salmonella Enteritidis and Salmonella Typhimurium, the two most important serovars of salmonellosis , during the fermentation of yogurt. The microorganisms were enumerated in milk throughout the fermentation process at three initial inoculum levels (3, 5 and 7 log CFU/mL). DMFit software was used in the fitting procedure of the data (IFR, Norwich, UK, Version 3.5). The data provided sigmoidal curves that were successfully displayed with the Baranyi model. The results showed that the initial inoculum level did not affect the growth for both pathogens; thus, the µ max values (maximum specific growth rate) did not significantly differ across all the contamination levels, ranging from 0.26 to 0.38 for S. Enteritidis and from 0.50 to 0.56 log CFU/g/h for S. Typhimurium ( P > 0.05). However, the µ max values significantly differed between the two serovars ( P < 0.05). The λ values (lag time) did not have a clear trend in either of the pathogens. The present study showed that Salmonella can survive the fermentation process of milk even at a low contamination level. In addition, the models presented in this study can be used in quantitative risk assessment studies to estimate the threat to consumers.

Structural and enzymatic characterization of a host-specificity determinant from Salmonella

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohler, Amanda C.; Spanò, Stefania; Galán, Jorge E.

The Salmonella effector protein GtgE functions as a cysteine protease to cleave a subset of the Rab-family GTPases and to prevent delivery of antimicrobial agents to the Salmonella-containing vacuole. GtgE is an effector protein from Salmonella Typhimurium that modulates trafficking of the Salmonella-containing vacuole. It exerts its function by cleaving the Rab-family GTPases Rab29, Rab32 and Rab38, thereby preventing the delivery of antimicrobial factors to the bacteria-containing vacuole. Here, the crystal structure of GtgE at 1.65 Å resolution is presented, and structure-based mutagenesis and in vivo infection assays are used to identify its catalytic triad. A panel of cysteine proteasemore » inhibitors were examined and it was determined that N-ethylmaleimide, antipain and chymostatin inhibit GtgE activity in vitro. These findings provide the basis for the development of novel therapeutic strategies to combat Salmonella infections.« less

Dynamics of Salmonella infection of macrophages at the single cell level.

PubMed

Gog, Julia R; Murcia, Alicia; Osterman, Natan; Restif, Olivier; McKinley, Trevelyan J; Sheppard, Mark; Achouri, Sarra; Wei, Bin; Mastroeni, Pietro; Wood, James L N; Maskell, Duncan J; Cicuta, Pietro; Bryant, Clare E

2012-10-07

Salmonella enterica causes a range of diseases. Salmonellae are intracellular parasites of macrophages, and the control of bacteria within these cells is critical to surviving an infection. The dynamics of the bacteria invading, surviving, proliferating in and killing macrophages are central to disease pathogenesis. Fundamentally important parameters, however, such as the cellular infection rate, have not previously been calculated. We used two independent approaches to calculate the macrophage infection rate: mathematical modelling of Salmonella infection experiments, and analysis of real-time video microscopy of infection events. Cells repeatedly encounter salmonellae, with the bacteria often remain associated with the macrophage for more than ten seconds. Once Salmonella encounters a macrophage, the probability of that bacterium infecting the cell is remarkably low: less than 5%. The macrophage population is heterogeneous in terms of its susceptibility to the first infection event. Once infected, a macrophage can undergo further infection events, but these reinfection events occur at a lower rate than that of the primary infection.

Assessing the potential impact of Salmonella vaccines in an endemically infected dairy herd

USDA-ARS?s Scientific Manuscript database

Salmonella spp. in cattle are contributing to bacterial foodborne disease for humans. Reduction of Salmonella prevalence in herds is important to prevent human Salmonella infections. Typical control measures are culling of infectious animals, vaccination, and improved hygiene management. Vaccines ha...

Environmental sampling to predict fecal prevalence of Salmonella in an intensively monitored dairy herd.

PubMed

Van Kessel, J S; Karns, J S; Wolfgang, D R; Hovingh, E; Jayarao, B M; Van Tassell, C P; Schukken, Y H

2008-10-01

Although dairy cattle are known reservoirs for salmonellae, cattle that are shedding this organism are often asymptomatic and difficult to identify. A dairy herd that was experiencing a sustained, subclinical outbreak of Salmonella enterica subsp. enterica Cerro was monitored for 2 years. Fecal samples from the lactating cows were collected every 6 to 8 weeks and tested for the presence of Salmonella. Fecal prevalence of Salmonella fluctuated throughout the observation period and ranged from 8 to 88%. Manure composites and water trough samples were collected along with the fecal samples, and bulk milk and milk filters were cultured for the presence of Salmonella on a weekly basis. Over 90% of the manure composites--representing high-animal-traffic areas-were positive at each sampling. Salmonella was detected in 11% of milk samples and in 66% of the milk filters. Results of weekly bulk milk quality testing (i.e., bulk tank somatic cell score, standard plate count, preliminary incubation count) were typically well within acceptable ranges. Milk quality variables had low correlations with herd Salmonella fecal prevalence. When observed over time, sampling period average prevalence of Salmonella in milk filters closely paralleled fecal prevalence of Salmonella in the herd. Based on results of this study, milk filters appear to be an effective method for monitoring shedding prevalence at the herd level. In-line filter testing is also a more sensitive measure of Salmonella, and perhaps other pathogens, in raw milk than testing the milk alone.

Analysis of Salmonella sp bacterial contamination on Vannamei Shrimp using binary logit model approach

NASA Astrophysics Data System (ADS)

Oktaviana, P. P.; Fithriasari, K.

2018-04-01

Mostly Indonesian citizen consume vannamei shrimp as their food. Vannamei shrimp also is one of Indonesian exports comodities mainstay. Vannamei shrimp in the ponds and markets could be contaminated by Salmonella sp bacteria. This bacteria will endanger human health. Salmonella sp bacterial contamination on vannamei shrimp could be affected by many factors. This study is intended to identify what factors that supposedly influence the Salmonella sp bacterial contamination on vannamei shrimp. The researchers used the testing result of Salmonella sp bacterial contamination on vannamei shrimp as response variable. This response variable has two categories: 0 = if testing result indicate that there is no Salmonella sp on vannamei shrimp; 1 = if testing result indicate that there is Salmonella sp on vannamei shrimp. There are four factors that supposedly influence the Salmonella sp bacterial contamination on vannamei shrimp, which are the testing result of Salmonella sp bacterial contamination on farmer hand swab; the subdistrict of vannamei shrimp ponds; the fish processing unit supplied by; and the pond are in hectare. This four factors used as predictor variables. The analysis used is Binary Logit Model Approach according to the response variable that has two categories. The analysis result indicates that the factors or predictor variables which is significantly affect the Salmonella sp bacterial contamination on vannamei shrimp are the testing result of Salmonella sp bacterial contamination on farmer hand swab and the subdistrict of vannamei shrimp ponds.

Heatwaves differentially affect risk of Salmonella serotypes.

PubMed

Milazzo, Adriana; Giles, Lynne C; Zhang, Ying; Koehler, Ann P; Hiller, Janet E; Bi, Peng

2016-09-01

Given increasing frequency of heatwaves and growing public health concerns associated with foodborne disease, we examined the relationship between heatwaves and salmonellosis in Adelaide, Australia. Poisson regression analysis with Generalised Estimating Equations was used to estimate the effect of heatwaves and the impact of intensity, duration and timing on salmonellosis and specific serotypes notified from 1990 to 2012. Distributed lag non-linear models were applied to assess the non-linear and delayed effects of temperature during heatwaves on Salmonella cases. Salmonella typhimurium PT135 notifications were sensitive to the effects of heatwaves with a twofold (IRR 2.08, 95% CI 1.14-3.79) increase in cases relative to non-heatwave days. Heatwave intensity had a significant effect on daily counts of overall salmonellosis with a 34% increase in risk of infection (IRR 1.34, 95% CI 1.01-1.78) at >41 °C. The effects of temperature during heatwaves on Salmonella cases and serotypes were found at lags of up to 14 days. This study confirms heatwaves have a significant effect on Salmonella cases, and for the first time, identifies its impact on specific serotypes and phage types. These findings will contribute to the understanding of the impact of heatwaves on salmonellosis and provide insights that could mitigate their impact. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.