Vibrio vulnificus, a ubiquitous inhabitant of coastal marine environments, has been isolated from a variety of sources. It is an opportunistic pathogen of both marine animals and humans. Here, the genome sequence of V. vulnificus Env1, an environmental isolate resistant to predation by the ciliate Tetrahymena pyriformis, is reported. Copyright © 2018 Noorian et al.
Methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 8 (CC8) sequence type 239 (ST239) represents a predominant hospital-associated MRSA sublineage present worldwide. The Canadian epidemic MRSA strains CMRSA3 and CMRSA6 are moderately virulent members of this group but are closely related to the highly virulent strain TW20. Whole-genome sequencing of CMRSA3 and CMRSA6 was conducted to identify genetic determinants associated with their virulence.
We sequenced the genomes of 17 strains isolated from the gut of honey bees, including strains representing the genera Lactobacillus, Bifidobacterium, Gilliamella, Snodgrassella, Frischella, and Commensalibacter. These genome sequences represent an important step forward in the development of a comprehensive reference database to aid future analysis of this emerging gut microbiota model.
Experiments using bacteriophage (phage) to infect bacterial strains have helped define some basic genetic concepts in microbiology, but our understanding of the complexity of bacterium-phage interactions is still limited. As the global threat of antibiotic resistance continues to increase, phage therapy has reemerged as an attractive alternative or supplement to treating antibiotic-resistant bacterial infections. Further, the long-used method of phage typing to classify bacterial strains is being replaced by molecular genetic techniques. Thus, there is a growing need for a complete understanding of the precise molecular mechanisms underpinning phage-bacterium interactions to optimize phage therapy for the clinic as well as for retrospectively interpreting phage typing data on the molecular level. In this study, a genomics-based fitness assay (TraDIS) was used to identify all host genes involved in phage susceptibility and resistance for a T4 phage infecting Shiga-toxigenic Escherichia coli O157. The TraDIS results identified both established and previously unidentified genes involved in phage infection, and a subset were confirmed by site-directed mutagenesis and phenotypic testing of 14 T4 and 2 T7 phages. For the first time, the entire sap operon was implicated in phage susceptibility and, conversely, the stringent starvation protein A gene (sspA) was shown to provide phage resistance. Identifying genes involved in phage infection and replication should facilitate the selection of bespoke phage combinations to target specific bacterial pathogens.IMPORTANCE Antibiotic resistance has diminished treatment options for many common bacterial infections. Phage therapy is an alternative option that was once popularly used across Europe to kill bacteria within humans. Phage therapy acts by using highly specific viruses (called phages) that infect and lyse certain bacterial species to treat the infection. Whole-genome sequencing has allowed modernization of the investigations into phage-bacterium interactions. Here, using E. coli O157 and T4 bacteriophage as a model, we have exploited a genome-wide fitness assay to investigate all genes involved in defining phage resistance or susceptibility. This knowledge of the genetic determinants of phage resistance and susceptibility can be used to design bespoke phage combinations targeted to specific bacterial infections for successful infection eradication. Copyright © 2018 Cowley et al.
Members of the species Kocuria rhizophila, belonging to the family Micrococcaceae in the phylum Actinobacteria, have been isolated from a wide variety of natural sources, such as soil, freshwater, fish gut, and clinical specimens. K. rhizophila is important from an industrial viewpoint, because the bacterium grows rapidly with high cell density and exhibits robustness at various growth conditions. However, the bacterium is an opportunistic pathogen involved in human infections. Here, we sequenced and analyzed the genome of the K. rhizophila strain BT304, isolated from the small intestine of adult castrated beef cattle.The genome of K. rhizophila BT304 consisted of a single circular chromosome of 2,763,150 bp with a GC content of 71.2%. The genome contained 2359 coding sequences, 51 tRNA genes, and 9 rRNA genes. Sequence annotations with the RAST server revealed many genes related to amino acid, carbohydrate, and protein metabolism. Moreover, the genome contained genes related to branched chain amino acid biosynthesis and degradation. Analysis of the OrthoANI values revealed that the genome has high similarity (>?97.8%) with other K. rhizophila strains, such as DC2201, FDAARGOS 302, and G2. Comparative genomic analysis further revealed that the antibiotic properties of K. rhizophila vary among the strains.The relatively small number of virulence-related genes and the great potential in production of host available nutrients suggest potential application of the BT304 strain as a probiotic in breeding beef cattle.
Mesorhizobium amorphae CCNWGS0123 was isolated in 2006, from effective nodules of Robinia pseudoacacia L. grown in lead-zinc mine tailing site, in Gansu Province, China. M. amorphae CCNWGS0123 is an aerobic, Gram-negative, non-spore-forming rod strain. This paper characterized M. amorphae CCNWGS0123 and presents its complete genome sequence information and genome annotation. The 7,374,589 bp long genome which encodes 7136 protein-coding genes and 63 RNA coding genes, contains one chromosome and four plasmids. Moreover, a chromosome with no gaps was assembled.
Coagulase negative staphylococci (CoNS) are commensal bacteria on human skin. Staphylococcus lugdunensis is a unique CoNS which produces various virulence factors and may, like S. aureus, cause severe infections, particularly in hospital settings. Unlike other staphylococci, it remains highly susceptible to antimicrobials, and genome-based phylogenetic studies have evidenced a highly conserved genome that distinguishes it from all other staphylococci.We demonstrate that S. lugdunensis possesses a closed pan-genome with a very limited number of new genes, in contrast to other staphylococci that have an open pan-genome. Whole-genome nucleotide and amino acid identity levels are also higher than in other staphylococci. We identified numerous genetic barriers to horizontal gene transfer that might explain this result. The S. lugdunensis genome has multiple operons encoding for restriction-modification, CRISPR/Cas and toxin/antitoxin systems. We also identified a new PIN-like domain-associated protein that might belong to a larger operon, comprising a metalloprotease, that could function as a new toxin/antitoxin or detoxification system.We show that S. lugdunensis has a unique genome profile within staphylococci, with a closed pan-genome and several systems to prevent horizontal gene transfer. Its virulence in clinical settings does not rely on its ability to acquire and exchange antibiotic resistance genes or other virulence factors as shown for other staphylococci.
Nontyphoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast, S Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in S Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal S Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of S Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of S Typhimurium (serovar I:4,[5],12:i:- sequence type 34 [ST34]) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34 S Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative Salmonella variants into susceptible human populations.IMPORTANCESalmonella Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid Salmonella (iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of Salmonella Typhimurium, the serovar I:4,[5],12:i:- ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of S Typhimurium and I:4,[5],12:i:- in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections. Copyright © 2018 Mather et al.
Brochothrix thermosphacta is one of the dominant bacterial species associated with spoilage of chilled meat and seafood products through the production of various metabolites responsible for off-odors. However, metabolic pathways leading to meat and seafood spoilage are not all well known. The production of spoiling molecules seems to depend both on strains and on food matrix. Several B. thermosphacta genome sequences have been reported, all issued from meat isolates. Here, we report four genome sequences, one complete and three as drafts. The four B. thermosphacta strains CD 337, TAP 175, BSAS1 3, and EBP 3070 were isolated from different ecological niches (seafood or meat products either spoiled or not and bovine slaughterhouse). These strains known as phenotypically and genetically different were selected to represent intraspecies diversity. CD 337 genome is 2,594,337 bp long, complete and circular, containing 2593 protein coding sequences and 28 RNA genes. TAP 175, BSAS1 3, and EBP 3070 genomes are arranged in 57, 83, and 71 contigs, containing 2515, 2668, and 2611 protein-coding sequences, respectively. These genomes were compared with two other B. thermosphacta complete genome sequences. The main genome content differences between strains are phages, plasmids, restriction/modification systems, and cell surface functions, suggesting a similar metabolic potential but a different niche adaptation capacity.
Austwickia chelonae, a species of Actinobacteria, is one of the pathogens that cause dermatophilosis in animals. Here, we report the complete genome se- quence of Austwickia chelonae LK16-18, which was isolated from cutaneous granulo- mas in crocodile lizards.
Arcticibacterium luteifluviistationis SM1504Twas isolated from Arctic surface seawater and classified as a novel genus of the phylum Bacteroides. To date, no Arcticibacterium genomes have been reported, their genomic compositions and metabolic features are still unknown. Here, we reported the complete genome sequence of A. luteifluviistationis SM1504T, which comprises 5,379,839bp with an average GC content of 37.20%. Genes related to various stress (such as radiation, osmosis and antibiotics) resistance and gene clusters coding for carotenoid and flexirubin biosynthesis were detected in the genome. Moreover, the genome contained a 245-kb genomic island and a 15-kb incomplete prophage region. A great percentage of proteins belonging to carbohydrate metabolism especially in regard to polysaccharides utilization were found. These related genes and metabolic characteristics revealed genetic basis for adapting to the diverse extreme Arctic environments. The genome sequence of A. luteifluviistationis SM1504Talso implied that the genus Arcticibacterium may act as a vital organic carbon matter decomposer in the Arctic seawater ecosystem.
We present here the complete genome sequence of Lactococcus lactis strain 14B4, isolated from almond drupes in northern California. This strain was observed to inhibit the growth of Salmonella enterica serotype Poona strain RM3363 in vitro.
Clostridium formicoaceticum, a Gram-negative mixotrophic homoacetogen, produces acetic acid as the sole metabolic product from various carbon sources, including fructose, glycerol, formate, and CO2. Its genome of 4.59-Mbp contains a highly conserved Wood-Ljungdahl pathway gene cluster with the same layout as that in other mixotrophic acetogens, including Clostridium aceticum, Clostridium carboxidivorans, and Clostridium ljungdahlii. For energy conservation, C. formicoaceticum does not have all the genes required for the synthesis of cytochrome or quinone used for generating proton gradient in H+-dependent acetogens such as Moorella thermoacetica; instead, it has the Rnf system and a Na+-translocating ATPase similar to the one in Acetobacterium woodii. Its growth in both heterotrophic and autotrophic media were dependent on the sodium concentration. C. formicoaceticum has genes encoding acetaldehyde dehydrogenases, alcohol dehydrogenases, and aldehyde oxidoreductases, which could convert acetyl-CoA and acetate to ethanol and butyrate to butanol under excessive reducing equivalent conditions. Copyright © 2018 Elsevier Inc. All rights reserved.
We report here, using third-generation, single-molecule, real-time DNA sequencing, the first complete genome sequence of Salmonella enterica serovar Worthington CFSAN051295, isolated from pistachios in the United States. The genome consists of a single 4.9-Mb chromosome.
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