Draft Genome Sequences of 21 Salmonella enterica Serovar Enteritidis Strains

Salmonella enterica subsp. enterica serovar Enteritidis is a common food-borne pathogen, often associated with shell eggs and poultry. Here, we report draft genomes of 21 S. Enteritidis strains associated with or related to the U.S.-wide 2010 shell egg recall. Eleven of these genomes were from environmental isolates associated with the egg outbreak, and 10 were reference isolates from previous years, unrelated to the outbreak. The whole-genome sequence data for these 21 human pathogen strains are being released in conjunction with the newly formed 100K Genome Project.     

Complete Nucleotide Sequences of Virulence-Resistance Plasmids Carried by Emerging Multidrug-Resistant Salmonella enterica Serovar Typhimurium Isolated from Cattle in Hokkaido,Japan

In the present study, we have shown that virulence-resistance plasmids from emerging multidrug-resistant isolates of Salmonella enterica serovar Typhimurium were derived from a virulence-associated plasmid, essential for systematic invasiveness of S. Typhimurium in mice (pSLT), through acquisition of a large insert containing a resistance island flanked by IS1294 elements. A bla _CMY-2-carrying plasmid from a cefotaxime-resistant isolate comprised a segment of Escherichia coli plasmid pAR060302 and the replication region (IncFIB) of a virulence-resistance plasmid. These results provide insights into the evolution of drug resistance in emerging clones of S. Typhimurium.     

Epidemiology of a Salmonella enterica subsp. enterica Serovar Typhimurium Strain Associated with a Songbird Outbreak

Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.     

Short-Term Signatures of Evolutionary Change in the Salmonella enterica Serovar Typhimurium 14028 Genome

Salmonella enterica serovar Typhimurium is a Gram-negative pathogen that causes gastroenteritis in humans and a typhoid-like disease in mice and is often used as a model for the disease promoted by the human-adapted S. enterica serovar Typhi. Despite its health importance, the only S. Typhimurium strain for which the complete genomic sequence has been determined is the avirulent LT2 strain, which is extensively used in genetic and physiologic studies. Here, we report the complete genomic sequence of the S. Typhimurium strain 14028s, as well as those of its progenitor and two additional derivatives. Comparison of these S. Typhimurium genomes revealed differences in the patterns of sequence evolution and the complete inventory of genetic alterations incurred in virulent and avirulent strains, as well as the sequence changes accumulated during laboratory passage of pathogenic organisms.The genomes of related bacteria can differ in three ways: (i) gene content, where one bacterial species or strain harbors genes absent from the other organism; (ii) nucleotide substitutions within largely conserved DNA sequences, which can result in amino acid changes in orthologous proteins, form pseudogenes, and promote distinct expression patterns of genes present in the two organisms; and (iii) changes in gene arrangement, caused by inversions and translocations. These differences have been observed not only across bacterial species but also among strains belonging to the same species. Recent genomic analyses have revealed that many bacterial pathogens of humans are virtually monomorphic (1) and exhibit very limited sequence diversity, raising questions about the nature of the genetic changes governing distinct behaviors. Furthermore, several bacterial pathogens that have been subjected to extensive passage in the laboratory display altered virulence characteristics, but the genetic basis for these alterations remains largely unknown. Here, we address both of these questions by determining and analyzing the genome sequences of closely related isolates of Salmonella enterica serovar Typhimurium, a Gram-negative pathogen that has been used as a preeminent model to investigate basic genetic mechanisms (2, 8, 46, 59), as well as the interaction between bacterial pathogens and mammalian hosts (11, 41).The genus Salmonella is divided into two species: Salmonella bongori and Salmonella enterica, which together comprise over 2,300 serovars differing in host specificity and the disease conditions they promote in various hosts. For example, S. enterica serovar Typhi is human restricted and causes typhoid fever, whereas serovar Typhimurium is a broad-host-range organism that causes gastroenteritis in humans and a typhoid-like disease in mice. Although the complete genome sequences of 15 Salmonella enterica strains are available, there is only a single representative of S. Typhimurium—strain LT2 (31). Despite its wide application in genetic analysis, strain LT2 is highly attenuated for virulence in both in vitro and in vivo assays (52, 56), leading many investigators to use other S. Typhimurium isolates to examine the genetic basis for bacterial pathogenesis (11, 14, 16).Over 300 virulence genes (3, 5, 47) have already been identified in Salmonella enterica serovar Typhimurium 14028 (now termed S. enterica subsp. enterica serovar Typhimurium ATCC 14028), which is a descendant of CDC 60-6516, a strain isolated in 1960 from pools of hearts and livers of 4-week-old chickens (P. Fields, personal communication). Whereas strain 14028 has been typed as LT2, a designation based on phage sensitivity (27), the two strains were isolated from distinct sources decades apart, which makes their genealogy and exact relationship obscure. A derivative of the original 14028 strain with a rough colony morphology (due to changes in O-antigen expression) was designated 14028r to distinguish it from the original smooth strain, renamed 14028s, and was used in a genetic screen for Salmonella virulence genes because it retained lethality for mice and the ability to survive within murine macrophages. Strain 14028 was also used for the identification of Salmonella genes that were specifically expressed during infection of a mammalian host (30). Both 14028 and LT2 possess a 90-kb virulence plasmid promoting intracellular replication and systemic disease (14), but they differ in their prophage contents, as is often the case among S. Typhimurium strains (12, 13).To identify the individual changes that differentiate S. Typhimurium strains and to assess the nature of variation that arises during laboratory storage and passage, we determined the genome sequence of strain 14028s. This genome was then used as a reference for sequencing its progenitors, including the original source strain CDC 60-6516 and the earliest smooth and rough variants. Our analysis uncovered the genomic differences that arose during the past decades of laboratory cultivation and showed that derivatives with different virulence potentials can follow distinct patterns of sequence evolution.     

Insights from the Genome Sequence of a Salmonella enterica Serovar Typhi Strain Associated with a Sporadic Case of Typhoid Fever in Malaysia

Salmonella enterica serovar Typhi is the causative agent of typhoid fever, which causes nearly 21.7 million illnesses and 217,000 deaths globally. Herein, we describe the whole-genome sequence of the Salmonella Typhi strain ST0208, isolated from a sporadic case of typhoid fever in Kuala Lumpur, Malaysia. The whole-genome sequence and comparative genomics allow an in-depth understanding of the genetic diversity, and its link to pathogenicity and evolutionary dynamics, of this highly clonal pathogen that is endemic to Malaysia.     

1株表现为鞭毛抗原3相的韦太夫雷登沙门氏菌的鉴定和基因组序列分析

利用高通量测序获取1株抗原式为3,10∶a,r,z6的沙门氏菌(Salmonella)GX150603的全基因组序列.根据鞭毛抗原序列、致病性和抗性基因预测GX150603的血清型,利用分子生物学软件分析基因组岛和前噬菌体,并与其他菌株进行全基因组系统发育分析.经鉴定GX150603为韦太夫雷登沙门氏菌(Salmone...     

Genome Sequence and Comparative Pathogenomics Analysis of a Salmonella enterica Serovar Typhi Strain Associated with a Typhoid Carrier in Malaysia

Salmonella enterica serovar Typhi is a human pathogen that causes typhoid fever predominantly in developing countries. In this article, we describe the whole genome sequence of the S. Typhi strain CR0044 isolated from a typhoid fever carrier in Kelantan, Malaysia. These data will further enhance the understanding of its host persistence and adaptive mechanism.     

Detection of Salmonella enterica Serovar Typhimurium by Using a Rapid, Array-Based Immunosensor

The multianalyte array biosensor (MAAB) is a rapid analysis instrument capable of detecting multiple analytes simultaneously. Rapid (15-min), single-analyte sandwich immunoassays were developed for the detection of Salmonella enterica serovar Typhimurium, with a detection limit of 8 × 10⁴ CFU/ml; the limit of detection was improved 10-fold by lengthening the assay protocol to 1 h. S. enterica serovar Typhimurium was also detected in the following spiked foodstuffs, with minimal sample preparation: sausage, cantaloupe, whole liquid egg, alfalfa sprouts, and chicken carcass rinse. Cross-reactivity tests were performed with Escherichia coli and Campylobacter jejuni. To determine whether the MAAB has potential as a screening tool for the diagnosis of asymptomatic Salmonella infection of poultry, chicken excretal samples from a private, noncommercial farm and from university poultry facilities were tested. While the private farm excreta gave rise to signals significantly above the buffer blanks, none of the university samples tested positive for S. enterica serovar Typhimurium without spiking; dose-response curves of spiked excretal samples from university-raised poultry gave limits of detection of 8 × 10³ CFU/g.     

Genome Sequence of Borrelia afzelii Strain HLJ01, Isolated from a Patient in China

We report here the genome sequence of Borrelia afzelii strain HLJ01, isolated from a patient with Lyme disease in China. It is the first report of the whole genome of a B. burgdorferi sensu lato isolate from a human in China.     

Complete Genome Sequence of Corynebacterium pseudotuberculosis Strain 1/06-A, Isolated from a Horse in North America

Corynebacterium pseudotuberculosis causes disease in several animal species, although distinct biovars exist that appear to be restricted to specific hosts. In order to facilitate a better understanding of the differences between biovars, we report here the complete genome sequence of the equine pathogen Corynebacterium pseudotuberculosis strain 1/06-A.     

Draft Genome Sequence of Staphylococcus vitulinus F1028, a Strain Isolated from a Block of Fermented Soybean

Staphylococcus vitulinus is a coagulase-negative staphylococcus in the family Staphylococcaceae. This report describes the draft genome sequence of S. vitulinus F1028, which was isolated from a traditional Korean soybean food (meju). This 2.56-Mbp genome sequence is the first S. vitulinus genome of a strain isolated from a fermented soybean product.     

Complete Genome Sequence of Brucella canis BCB018, a Strain Isolated from a Human Patient

Brucella canis is considered a rare cause of human brucellosis because of difficulties in presumptive diagnosis and underestimation of the incidence. Here, we report the draft genome sequence of a Brucella canis isolate, BCB018, isolated from a human patient, providing precious resources for comparative genomics analysis of Brucella field strains.     

Draft Genome Sequence of Ureibacillus thermosphaericus Strain Thermo-BF, Isolated from Ramsar Hot Springs in Iran

Ureibacillus thermosphaericus strain Thermo-BF is an aerobic, thermophilic bacillus which has been characterized to biosynthesize gold nanoparticles. Here we present the draft genome sequence of Ureibacillus thermosphaericus strain Thermo-BF which consists of a 2,864,162-bp chromosome. This is the first report of a shotgun sequenced draft genome of a species in the Ureibacillus genus.     

Draft Genome Sequence of Escherichia coli W26, an Enteric Strain Isolated from Cow Feces

An enteric bacterium, Escherichia coli W26 (KACC 16630), was isolated from feces from a healthy cow in South Korea. Here, we report the draft genome sequence of the isolate, which is closely affiliated with commensal strains belonging to E. coli phylogroup B1.     

Draft Genome Sequence of Moritella dasanensis Strain ArB 0140, a Psychrophilic Bacterium Isolated from the Arctic Ocean

The psychrophilic bacterium Moritella dasanensis strain ArB 0140 was isolated near a glacier in Kongsfjorden, Svalbard Archipelago, Norway. Here we report a 4.89-Mb draft genome sequence of Moritella dasanensis ArB 0140, which could provide comprehensive information on a psychrophilic mechanism in extreme environments.     

Structural and Functional Characterization of Three DsbA Paralogues from Salmonella enterica Serovar Typhimurium

In prototypic Escherichia coli K-12 the introduction of disulfide bonds into folding proteins is mediated by the Dsb family of enzymes, primarily through the actions of the highly oxidizing protein EcDsbA. Homologues of the Dsb catalysts are found in most bacteria. Interestingly, pathogens have developed distinct Dsb machineries that play a pivotal role in the biogenesis of virulence factors, hence contributing to their pathogenicity. Salmonella enterica serovar (sv.) Typhimurium encodes an extended number of sulfhydryl oxidases, namely SeDsbA, SeDsbL, and SeSrgA. Here we report a comprehensive analysis of the sv. Typhimurium thiol oxidative system through the structural and functional characterization of the three Salmonella DsbA paralogues. The three proteins share low sequence identity, which results in several unique three-dimensional characteristics, principally in areas involved in substrate binding and disulfide catalysis. Furthermore, the Salmonella DsbA-like proteins also have different redox properties. Whereas functional characterization revealed some degree of redundancy, the properties of SeDsbA, SeDsbL, and SeSrgA and their expression pattern in sv. Typhimurium indicate a diverse role for these enzymes in virulence.     

Genome Sequence of Multidrug-Resistant Escherichia coli EC302/04, Isolated from a Human Tracheal Aspirate

Escherichia coli is an important etiologic agent of lower respiratory tract infections (LRTI). Multidrug-resistant E. coli EC302/04 was isolated from a tracheal aspirate, and its genome sequence is expected to provide insights into antimicrobial resistance as well as adaptive and virulence mechanisms of E. coli involved in LRTI.     

Interaction of Candida albicans with an Intestinal Pathogen,Salmonella enterica Serovar Typhimurium

Candida albicans is an opportunistic human fungal pathogen that normally resides in the gastrointestinal tract and on the skin as a commensal but can cause life-threatening invasive disease. Salmonella enterica serovar Typhimurium is a gram-negative bacterial pathogen that causes a significant amount of gastrointestinal infection in humans. Both of these organisms are also pathogenic to the nematode Caenorhabditis elegans, causing a persistent gut infection leading to worm death. In the present study, we used a previously developed C. elegans polymicrobial infection model to assess the interactions between S. Typhimurium and C. albicans. We observed that when C. elegans is infected with C. albicans and serovar Typhimurium, C. albicans filamentation is inhibited. The inhibition of C. albicans filamentation by S. Typhimurium in C. elegans appeared to be mediated by a secretary molecule, since filter-sterilized bacterial supernatant was able to inhibit C. albicans filamentation. In vitro coculture assays under planktonic conditions showed that S. Typhimurium reduces the viability of C. albicans, with greater effects seen at 37°C than at 30°C. Interestingly, S. Typhimurium reduces the viability of both yeast and filamentous forms of C. albicans, but the killing appeared more rapid for the filamentous cells. The antagonistic interaction was also observed in a C. albicans biofilm environment. This study describes the interaction between two diverse human pathogens that reside within the gastrointestinal tract and shows that the prokaryote, S. Typhimurium, reduces the viability of the eukaryote, C. albicans. Identifying the molecular mechanisms of this interaction may provide important insights into microbial pathogenesis.Candida albicans, the most common human fungal pathogen, is a prototypical opportunistic organism that lives harmlessly in the human gastrointestinal tract but has the ability to cause life-threatening invasive disease. Bloodstream infection with C. albicans remains the most lethal form (10), with translocation of the gastrointestinal mucosa being an important pathogenic mechanism, especially in hemato-oncology patients and those who have undergone abdominal surgery. A key virulence determinant of C. albicans is its ability to transition from yeast to a filamentous form (16, 17, 19, 22). This morphogenesis appears important for tissue adherence and invasion (22). Furthermore, C. albicans has the ability to form complex biofilms on medical devices (13) and on human mucosal surfaces, such as the gastrointestinal and bronchial mucosa. C. albicans biofilm formation has immense clinical and economic consequences (13).Recently the interactions between this important fungal pathogen and bacteria were described (11, 12, 18). These studies focus on the interaction between C. albicans and nonfermenting, gram-negative bacteria, such as Pseudomonas aeruginosa and Acinetobacter baumannii, whose interactions are likely found in the clinical environment, especially in the respiratory tracts of critically ill patients and on wounds of patients with burn injuries (7, 20). Of interest, these bacteria show antagonistic properties toward C. albicans, with a predilection toward reducing the viability of C. albicans filaments. In order to study these prokaryote-eukaryote interactions, our laboratory developed a polymicrobial infection model system using Caenorhabditis elegans as a substitute host (18). Previously, we showed that C. albicans causes a persistent lethal infection of the C. elegans intestinal tract (6). This leads to overwhelming C. albicans intestinal proliferation with subsequent filamentation through the worm cuticle (6). Given these characteristics, we decided to use this model to study the interaction of C. albicans with another intestinal pathogen, Salmonella enterica serovar Typhimurium.S. Typhimurium is a gram-negative organism that belongs to the Enterobacteriaceae family. It is a gastrointestinal tract pathogen of humans, being responsible for approximately 2 million to 4 million cases of enterocolitis each year in the United States (4, 8, 21, 23). During infection, S. Typhimurium competes with normal intestinal flora (23). Its virulence pathways are well described, and it has been shown to cause a persistent and lethal gut infection of the nematode C. elegans, similar to infection seen with C. albicans (1, 14). Given this and the fact that C. albicans is a common inhabitant of the human gastrointestinal tract, we used the C. elegans polymicrobial infection model (18) to study the interactions between S. Typhimurium and C. albicans. Understanding the interactions between these diverse organisms within the complex milieu of an intestinal tract may provide important pathogenic and therapeutic insights.     

Draft Genome Sequence of Bacillus isronensis Strain B3W22, Isolated from the Upper Atmosphere

We report the 4.0-Mb genome sequence of Bacillus isronensis strain B3W22 isolated from air collected at an altitude ranging from 27 to 30 km above the city of Hyderabad, in India. This genome sequence will contribute to the objective of determining the microbial diversity of the upper atmosphere.