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1.
Chai-Hoon Khoo Yoke-Kqueen Cheah Learn-Han Lee Jiun-Horng Sim Noorzaleha Awang Salleh Shiran Mohd Sidik Son Radu Sabrina Sukardi 《Antonie van Leeuwenhoek》2009,96(4):441-457
The increased occurrence of Salmonella occurrence in local indigenous vegetables and poultry meat can be a potential health hazards. This study is aimed to detect
the prevalence of twenty different virulence factors among Salmonella enterica strains isolated from poultry and local indigenous vegetables in Malaysia via an optimized, rapid and specific multiplex
PCR assay. The assay encompasses a total of 19 Salmonella pathogenicity islands genes and a quorum sensing gene (sdiA) in three multiplex reaction sets. A total of 114 Salmonella
enterica isolates belonging to 38 different serovars were tested. Each isolate in under this study was found to possess up to 70%
of the virulence genes tested and exhibited variable pathogenicity gene patterns. Reproducibility of the multiplex PCR assay
was found to be 100% and the detection limit of the optimized multiplex PCR was tested with lowest detectable concentration
of DNA 0.8 pg μl−1. This study demonstrated various Salmonella pathogenicity island virulence gene patterns even within the same serovar. This sets of multiplex PCR system provide a fast
and reliable typing approach based on Salmonella pathogenicity islands, thus enabling an effective monitoring of emerging pathogenic Salmonella strains as an additional tool in Salmonella surveillance studies. 相似文献
2.
Salmonella enterica is divided into four subspecies containing a large number of different serovars, several of which are important zoonotic
pathogens and some show a high degree of host specificity or host preference. We compare 45 sequenced S. enterica genomes that are publicly available (22 complete and 23 draft genome sequences). Of these, 35 were found to be of sufficiently
good quality to allow a detailed analysis, along with two Escherichia coli strains (K-12 substr. DH10B and the avian pathogenic E. coli (APEC O1) strain). All genomes were subjected to standardized gene finding, and the core and pan-genome of Salmonella were estimated to be around 2,800 and 10,000 gene families, respectively. The constructed pan-genomic dendrograms suggest
that gene content is often, but not uniformly correlated to serotype. Any given Salmonella strain has a large stable core, whilst there is an abundance of accessory genes, including the Salmonella pathogenicity islands (SPIs), transposable elements, phages, and plasmid DNA. We visualize conservation in the genomes in
relation to chromosomal location and DNA structural features and find that variation in gene content is localized in a selection
of variable genomic regions or islands. These include the SPIs but also encompass phage insertion sites and transposable elements.
The islands were typically well conserved in several, but not all, isolates—a difference which may have implications in, e.g.,
host specificity. 相似文献
3.
Kenneth P. Smith Jeffy George Kathleen M. Cadle Sanath Kumar Steven J. Aragon Ricardo L. Hernandez Suzanna E. Jones Jody L. Floyd Manuel F. Varela 《World journal of microbiology & biotechnology》2010,26(6):1025-1031
In this study, we investigated the antimicrobial susceptibility profiles and the distribution of some well known genetic determinants
of virulence in clinical isolates of Salmonella enterica from New Mexico. The minimum inhibitory concentrations for various antimicrobials were determined by using the E-test strip
method according to CLSI guidelines. Virulence genotyping was performed by polymerase chain reaction (PCR) using primers specific
for known virulence genes of S. enterica. Of 15 isolates belonging to 11 different serovars analyzed, one isolate of Salmonella Typhimurium was resistant to multiple drugs namely ampicillin, amoxicillin/clavulanic acid, chloramphenicol and tetracycline,
that also harbored class 1 intergron, bla
TEM encoding genes for β-lactamase, chloramphenicol acetyl transferase (cat1), plus floR, tet(C) and tet(G). This strain was phage typed as DT104. PCR analysis revealed the presence of invA, hilA, stn, agfA and spvR virulence genes in all the isolates tested. The plasmid-borne pefA gene was absent in 11 isolates, while 5 isolates lacked sopE. One isolate belonging to serogroup E4 (Salmonella Sombre) was devoid of multiple virulence genes pefA, iroB, shdA and sopE. These results demonstrate that clinical Salmonella serotypes from New Mexico used here are predominantly sensitive to multiple antimicrobial agents, but vary in their virulence
genotypes. Information on antimicrobial sensitivity and virulence genotypes will help in understanding the evolution and spread
of epidemic strains of S. enterica in the region of study. 相似文献
4.
Background
Salmonella enterica serovar Typhi and Typhimurium are closely related serovars as indicated by >96% DNA sequence identity between shared genes. Nevertheless, S. Typhi is a strictly human-specific pathogen causing a systemic disease, typhoid fever. In contrast, S. Typhimurium is a broad host range pathogen causing only a self-limited gastroenteritis in immunocompetent humans. We hypothesize that these differences have arisen because some genes are unique to each serovar either gained by horizontal gene transfer or by the loss of gene activity due to mutation, such as pseudogenes. S. Typhi has 5% of genes as pseudogenes, much more than S. Typhimurium which contains 1%. As a consequence, S. Typhi lacks several protein effectors implicated in invasion, proliferation and/or translocation by the type III secretion system that are fully functional proteins in S. Typhimurium. SseJ, one of these effectors, corresponds to an acyltransferase/lipase that participates in SCV biogenesis in human epithelial cell lines and is needed for full virulence of S. Typhimurium. In S. Typhi, sseJ is a pseudogene. Therefore, we suggest that sseJ inactivation in S. Typhi has an important role in the development of the systemic infection. 相似文献5.
Huang LJ Cui J Piao HH Hong Y Choy HE Ryu PY 《Journal of microbiology (Seoul, Korea)》2010,48(5):663-667
Cytolysin A (ClyA) is a pore-forming hemolytic protein encoded by the clyA gene. It has been identified in Salmonella enterica serovars Typhi and Paratyphi A. To identify and characterize the clyA genes in various Salmonella enterica strains, 21 different serotypes of strains isolated from clinical specimens were presently examined. Full-length clyA genes were found in S. enterica serovar Brandenburg, Indiana, Panama, and Schwarzengrund strains by polymerase chain reaction amplification. The ClyA proteins
from these four strains showed >97% amino acid identity to that of S. enterica serovar Typhi. Although all four serovars expressed detectable levels of ClyA as determined by Western blot analysis, they
did not show a strong hemolytic effect on blood agar, indicating that ClyA may not be efficiently expressed or secreted. Escherichia coli transformed with clyA genes from the four serovars enhanced production of ClyA proteins and hemolytic activities to a level similar to S. enterica serovar Typhi ClyA. The present results suggest that ClyA may play a role in the pathogenesis of S. enterica serovar Brandenburg, Indiana, Panama and Schwarzengrund. 相似文献
6.
Mohammad Jahangir Alam David Renter Ethel Taylor Diana Mina Rodney Moxley David Smith 《Current microbiology》2009,58(4):354-359
Salmonella enterica in cattle production systems may be associated with important human and animal disease issues. However, tremendous diversity
exists among Salmonella recovered, and more information is needed about strains of greatest potential health concern, particularly those that are
multidrug resistant (MDR). By characterizing Salmonella isolates from commercial feedlot pens, this study aimed to evaluate the strain diversity and prevalence of MDR Salmonella from different types of composite pen samples. Antimicrobial susceptibility profiles, serotype, and presence or absence of
the integron-encoded intI1 gene were determined for 530 Salmonella isolates recovered using composite rope (n = 335), feces (n = 59), and water (n = 136) samples from 21 pens in 3 feedlots. The study investigated only pens with available isolates from multiple sample
types. Most isolates (83.0%) of the 19 Salmonella serotypes identified were susceptible or intermediately susceptible to all the antimicrobials evaluated. Resistance to sulfisoxazole
(14.9%), streptomycin (3.8%), and tetracycline (3.6%) were the most common. None of the isolates tested positive for a class
1 integron, and only 2.5% were resistant to multiple antimicrobials. All the MDR isolates, namely, serotypes Uganda (n = 9), Typhimurium (n = 2), and Give (n = 2), were resistant to at least five antimicrobials. Most MDR isolates (n = 11) were from two pens during 1 week within one feedlot. Overall, many Salmonella isolates collected within a pen were similar in terms of serotype and antimicrobial susceptibility regardless of sample type.
However, MDR Salmonella and rare serotypes were not recovered frequently enough to suggest a general strategy for appropriate composite sampling
of feedlot cattle populations for Salmonella detection and monitoring. 相似文献
7.
Background
Salmonella enterica serotype Enteritidis (SE) is considered to be one of the most potent pathogenic Salmonella serotypes causing food-borne disease in humans. Since a live bacterial vaccine based on surface display of antigens has many advantages over traditional vaccines, we have studied the surface display of the SE antigenic proteins, H:gm and SefA in Escherichia coli by the β-autotransporter system, AIDA. This procedure was compared to protein translocation in Staphylococcus carnosus, using a staphylococci hybrid vector earlier developed for surface display of other vaccine epitopes. 相似文献8.
Natural variation in the presence or the absence of STM0517-0529 genes allowing allantoin utilisation has been described in
field isolates of the multidrug resistant Salmonella enterica serovar Typhimurium belonging to the phage type DT104. Interestingly, S. enterica subspecies enterica serovar Typhimurium DT104 is quite frequent in pigs and cattle, but rarely present in egg-laying hens. Taking into account
the different mode of allantoin metabolism in birds and mammals, we were interested in whether the absence of STM0517-0529
genes may disable this clone in poultry colonisation. We have therefore constructed the allB (also designated as STM0523) mutants in S. enterica subspecies enterica serovar Typhimurium and S. enterica subspecies enterica serovar Enteritidis, and with these, we infected mice, newly hatched chickens and adult egg-laying hens to show that the
defect in allantoin utilisation does not influence S. enterica virulence for mice or adult hens, but slightly decreases virulence of S. enterica for chickens. The decrease in virulence of the allB mutant was relatively minor as it could be observed only after a mixed infection model, consistent with a lower prevalence,
but not a total absence of such clones in poultry flocks. 相似文献
9.
Aminoglycoside resistance in six clinically isolated Staphylococcus aureus was evaluated. Genotypical examination revealed that three isolates (HLGR-10, HLGR-12, and MSSA-21) have aminoglycoside-modifying
enzyme (AME) coding genes and another three (GRSA-2, GRSA-4, and GRSA-6) lacked these genes in their genome. Whereas isolates
HLGR-10 and HLGR-14 possessed bifunctional AME coding gene aac(6′)-aph(2′′), and aph(3′)-III and showed high-level resistance to gentamycin and streptomycin, MSSA-21 possessed aph(3′)-III and exhibited low resistance to gentamycin, streptomycin, and kanamycin. The remaining three isolates (GRSA-2, GRSA-4, and
GRSA-6) exhibited low resistance to all the aminoglycosides because they lack aminoglycoside-modifying enzyme coding genes
in their genome. The transmission electron microscopy of the three isolates revealed changes in cell size, shape, and septa
formation, supporting the view that the phenomenon of adaptive resistance is operative in these isolates. 相似文献
10.
Roux SR Hackauf B Linz A Ruge B Klocke B Wehling P 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,110(1):202-201
Three dominant resistance genes, Pr3, Pr4, and Pr5, were identified by genetic analysis of resistance to leaf rust in rye (Puccinia recondita f. sp. secalis). Each of the three genes confers resistance to a broad scale of single-pustule isolates (SPIs), but differences could be observed for specific Pr gene/SPI combinations. Resistance conferred by the three genes was effective in both detached-leaf tests carried out on seedlings and in field tests of adult plants. Molecular marker analysis mapped Pr3 to the centromeric region of rye chromosome arm 1RS, whereas Pr4 and Pr5 were assigned to the centromeric region of 1RL. Chromosomal localization and reaction patterns to specific SPIs provide evidence that the three Pr genes represent distinct and novel leaf-rust resistance genes in rye. The contributions of these genes to resistance breeding in rye and wheat are discussed.The authors dedicate this paper to Prof. Dr. H.H. Geiger, University of Hohenheim, on the occasion of his 65th birthday.An erratum to this article can be found at 相似文献
11.
Joanna Mokracka Sylwia Krzymińska Danił Ałtunin Dariusz Wasyl Ryszard Koczura Krzysztof Dudek Monika Dudek Zofia Anna Chyleńska Anna Ekner-Grzyb 《Antonie van Leeuwenhoek》2018,111(10):1863-1870
The aim of this study was to estimate virulence potential of Salmonella enterica strains colonizing the gut of free-living sand lizards (Lacerta agilis L.). The strains belonged to three Salmonella serovars: Abony, Schleissheim, and Telhashomer. Adhesion and invasion abilities of the strains were determined in quantitative assays using the gentamicin protection method. Induction of apoptosis was assessed using HeLa cell monolayers. PCR assays were used for detection of 26 virulence genes localised within mobile elements: pathogenicity islands, virulence plasmids, and prophage sequences. In vitro studies revealed that all strains had adhesion and invasion abilities to human epithelial cells. The isolates were cytotoxic and induced apoptosis of the cells. The serovars differed in the number of virulence-associated genes: up to 18 genes were present in Salmonella Schleissheim, 17 in Salmonella Abony, whereas as few as six genes were found in Salmonella Telhashomer. Generally, Salmonella Abony and Salmonella Schleissheim did not differ much in gene content connected with the presence SPI-1 to -5. All of the strains lacked genes localised within bacteriophages and plasmids. The presence of virulence-associated genes and in vitro pathogenicity assays suggest that Salmonella sp. strains originating from autochthonous, free-living lizards can potentially infect and cause disease in humans. 相似文献
12.
13.
Background
Salmonella spp. have been isolated from a wide range of wild animals. Opportunistic wild carnivores such as red foxes (Vulpes vulpes) and badgers (Meles meles) may act as environmental indicators or as potential sources of salmonellosis in humans. The present study characterizes Salmonella spp. isolated from the intestinal contents of hunted or dead red foxes (n?=?509) and badgers (n?=?17) in northern Italy.Findings
Thirty-one strains of Salmonella belonging to 3 Salmonella enterica subspecies were isolated. Fourteen different serovars of S. enterica subsp. enterica were identified, among which were serovars often associated with human illness.Conclusions
Wild opportunistic predators can influence the probability of infection of both domestic animals and humans through active shedding of the pathogen to the environment. The epidemiological role of wild carnivores in the spread of salmonellosis needs to be further studied.14.
Porteen Kannan Mahesh Dharne Allen Smith Jeffrey Karns Arvind A. Bhagwat 《Current microbiology》2009,59(6):641-645
15.
Eva Litrup Mia Torpdahl Burkhard Malorny Stephan Huehn Morten Helms Henrik Christensen Eva M Nielsen 《BMC microbiology》2010,10(1):96
Background
Salmonella enterica subsp. enterica is one of the leading food-borne pathogens in the USA and European countries. Outcome of human Salmonella serotype Typhimurium infections ranges from mild self-limiting diarrhoea to severe diarrhoea that requires hospitalization. Increased knowledge of the mechanisms that are responsible for causing infection and especially the severity of infection is of high interest. 相似文献16.
Alicia Alonso-Hernando Rosa Capita Miguel Prieto Carlos Alonso-Calleja 《Journal of microbiology (Seoul, Korea)》2009,47(2):142-146
Information on the potential for acquired reduced susceptibility of bacteria to poultry decontaminants occurring is lacking.
Minimal Inhibitory Concentrations (MICs) were established for assessing the initial susceptibility and the adaptative and
cross-adaptative responses of four bacterial strains (Listeria monocytogenes serovar l/2a, L. monocytogenes serovar 4b, Salmonella enterica serotype Typhimurium, and S. enterica serotype Enteritidis) to four poultry decontaminants (trisodium phosphate, acidified sodium chlorite -ASC-, citric acid,
and peroxyacetic acid). The initial susceptibility was observed to differ among species (all decontaminants) and between Salmonella strains (ASC). These inter- and intra-specific variations highlight (1) the need for strict monitoring of decontaminant concentrations
to inactivate all target pathogens of concern, and (2) the importance of selecting adequate test strains in decontamination
studies. MICs of ASC (0.17±0.02 to 0.21±0.02 mg/ml) were higher than the U.S. authorized concentration when applied as a pre-chiller
or chiller solution (0.05 to 0.15 mg/ml). Progressively increasing decontaminant concentrations resulted in reduced susceptibility
of strains. The highest increase in MIC was 1.88 to 2.71-fold (ASC). All decontaminants were shown to cause cross-adaptation
of strains between both related and unrelated compounds, the highest increase in MIC being 1.82-fold (ASC). Our results suggest
that the in-use concentrations of ASC could, in certain conditions, be ineffective against Listeria and Salmonella strains. The adaptative and cross-adaptative responses of strains tested to poultry decontaminants are of minor concern.
However, the observations being presented here are based on in vitro studies, and further research into practical applications are needed in order to confirm these findings. 相似文献
17.
Yoke-Kqueen Cheah Noorzaleha Awang Salleh Learn-Han Lee Son Radu Sabrina Sukardi Jiun-Horng Sim 《World journal of microbiology & biotechnology》2008,24(3):327-335
Salmonella enterica subsp. enterica (S.) serovar Weltevreden has emerged as a public health problem in many countries. Genomic DNA of S. Weltevreden from indigenous vegetables namely ‘selom’ (Oenanthe stolonifera), ‘pegaga’ (Centella asiatica), ‘kesum’ (Polygonum minus) and ‘kangkong’ (Ipomoea aquatica) were characterized by duplex-polymerase chain reaction (duplex-PCR), multiplex-polymerase chain reaction (multiplex-PCR),
random amplified polymorphic DNA (RAPD), enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR)
and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results demonstrated that a total of
four clusters and three single isolates were generated from ERIC-PCR with primers ERIC-1 and ERIC-2 whereas RAPD with arbitrary
primers OPAR2, OPAR17 and OPAR19 discriminated the S. Weltevreden into nine clusters and eight single isolates at a common 65% similarity level with discriminatory index (D) of 0.7443 and 0.9394 respectively. Composite analysis of banding profiles generated from RAPD-PCR and ERIC-PCR showed eight
clusters and six single isolates at 65% similarity level with the highest D value that is 0.9508. On the other hand, PCR-RFLP and duplex PCR data exhibited a consistent profile for S. Weltevreden. Multiplex-PCR targeting three different antibiotic resistance genes and a common Salmonella specific gene segment produced two distinguishing profiles among the S. Weltevreden examined. These results demonstrated that the combined analysis of RAPD-PCR and ERIC-PCR is a better tool for
characterizing S. Weltevreden than individual methods. 相似文献
18.
Salmonella causes the majority of infections in humans and homeothermic animals. This article describes a specific polymerase chain
reaction (PCR) method developed for a rapid identification of Salmonella. A gyrB-targeted species-specific primer pair, S-P-for (5′-GGT GGT TTC CGT AAA AGT A-3′) and S-P-rev (5′-GAA TCG CCT GGT TCT TGC-3′),
was successfully designed. PCR with all the Salmonella strains produced a 366- bp DNA fragment that was absent from all the non-Salmonella strains tested. The detection limit of the PCR was 0.01 ng with genomic DNA or 3.2 cells per assay. Good specificity was
also demonstrated by fecal samples, from which only the gyrB gene of Salmonella was amplified. Using the culture-PCR method, 27 isolates on Salmonella-Shigella (SS) medium were rapidly identified as Salmonella, which was confirmed by the sequencing of the gyrB gene. 相似文献
19.
20.
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. 相似文献