27 research outputs found
All hope is not lost: development of a bacteriophage cocktail to control Salmonella biofilms under chicken, pig and human gut conditions
No full textSalmonella causes gastroenteritis via consumption of contaminated water, poultry, pork or beef products. Salmonellosis affects ~550 million people, causes ~33 million deaths and costs ~$3.7 billion to treat per year globally. The situation is compounded by rising antimicrobial resistance (AMR) and dwindling antibiotic innovations. Whilst antibiotics may be helpful, they have limited efficacy in biofilms, a protective extracellular matrix produced by many bacteria including Salmonella. To effectively control Salmonella and mitigate the general impending global AMR crisis, effective alternatives are needed to augment or replace antibiotics. Here, we present data to support the use of phages which we show can penetrate biofilms and kill Salmonella. They could therefore be used as a control strategy in water, given to animals pre-harvest or during food processing. We optimised a broad host range six-phage (five myoviruses and a siphovirus) cocktail that effectively lysed important serovars including the monophasic strains. We determined the biofilm properties of representative chicken and pig associated strains aerobically at 37oC, and anaerobically at 37 and 40oC to mimic growing conditions of Salmonella and guts of humans, swine and poultry. Treating established biofilms with the cocktail caused a significant decrease (
Erratum to: Is Sensory Loss an Understudied Risk Factor for Frailty? A Systematic Review and Meta-analysis
No full textIn the article “Is Sensory Loss an Understudied Risk Factor for Frailty? A Systematic Review and Meta-analysis,” an author was missing. Ana Maseda should be listed as the 11th author. The correct author list is: Benjamin Kye Jyn Tan, Ryan Eyn Kidd Man, Alfred Tau Liang Gan, Eva K Fenwick, Varshini Varadaraj, Bonnielin K Swenor, Preeti Gupta, Tien Yin Wong, Caterina Trevisan, Laura Lorenzo-López, Ana Maseda, José Carlos Millán-Calenti, Carla Helena Augustin Schwanke, Ann Liljas, Soham Al Snih, Yasuharu Tokuda, Ecosse Luc Lamoureux. This error has been corrected
Fleas of fleas: The potential role of bacteriophages in Salmonella diversity and pathogenicity.
Full text linkNon-typhoidal salmonellosis is an important foodborne and zoonotic infection, that causes significant global public health concern. Diverse serovars are multidrug-resistant and encode several virulence indicators, however, little is known on the role prophages play in driving these characteristics. Here, we extracted prophages from 75 Salmonella genomes, which represent the 15 most important serovars in the United Kingdom. We analysed the genomes of the intact prophages for the presence of virulence factors which were associated with; diversity, evolution and pathogenicity of Salmonella and to establish their genomic relationships. We identified 615 prophage elements from the Salmonella genomes, from which 195 prophages are intact, 332 being incomplete while 88 are questionable. The average prophage carriage was found to be more prevalent in S. Heidelberg, S. Inverness and S. Newport (10.2-11.6 prophages/strain), compared to S. Infantis, S. Stanley, S. Typhimurium and S. Virchow (8.2-9 prophages/strain) and S. Agona, S. Braenderup, S. Bovismorbificans, S. Choleraesuis, S. Dublin, and S. Java (6-7.8 prophages/strain), and S. Javiana and S. Enteritidis (5.8 prophages/strain). Cumulatively, 2760 virulence factors were detected from the intact prophages and associated with cellular functionality being linked to effector delivery/secretion system (73%), adherence (22%), magnesium uptake (2.7%), resistance to antimicrobial peptides (0.94%), stress/survival (0.4%), exotoxins (0.32%) and antivirulence (0.18%). Close and distant clusters were formed among the prophage genomes suggesting different lineages and associations with bacteriophages of other Enterobacteriaceae. We show that diverse repertoire of Salmonella prophages are associated with numerous virulence factors, and may contribute to diversity, pathogenicity and success of specific serovars
The Potential Roles of Prophages in the Pathogenicity of Klebsiella pneumoniae Strains from Kenya
Full text linkBackground/Objectives: Antimicrobial resistance (AMR) in Klebsiella pneumoniae poses a serious threat to healthcare, especially in sub-Saharan Africa (SSA). To complement AMR infection control in Kenya, here, clinical and environmental genomes were investigated to determine the potential roles prophages play in K. pneumoniae pathogenicity. Methods: Prophages were extracted from 89 Kenyan K. pneumoniae genomes. The intact prophages were examined for virulence genes carriage, and their phylogenetic relationships were established. Results: Eighty-eight (~99%) of the genomes encode at least a single prophage, and there is an average of four prophages and 2.8% contributory genomes per bacterial strain. From the 364 prophages identified, 250 (68.7%) were intact, while 58 (15.9%) and 57 (15.7%) were questionable and incomplete, respectively. Approximately, 30% of the intact prophages encode 38 virulence genes that are linked to iron uptake (8), regulation (6), adherence (5), secretion system (4), antiphagocytosis (4), autotransporter (4), immune modulation (3), invasion (2), toxin (1) and cell surface/capsule (1). Phylogenetic analyses revealed three distinct clades of the intact prophages irrespective of their hosts, sources and locations, which support the plasticity of the genomes and potential to mediate horizontal gene transfer. Conclusions: This study provides first evidence showing the diverse prophages that are encoded in K. pneumoniae from SSA with particular focus on Kenyan strains. This also shows the potential roles these prophages play in the pathogenicity and success of K. pneumoniae and could improve knowledge and complement control strategies in the region and across the globe. Further work is needed to show the expression of these genes through lysogenisation
Fleas of fleas: The potential role of bacteriophages in Salmonella diversity and pathogenicity.
Full text linkNon-typhoidal salmonellosis is an important foodborne and zoonotic infection, that causes significant global public health concern. Diverse serovars are multidrug-resistant and encode several virulence indicators, however, little is known on the role prophages play in driving these characteristics. Here, we extracted prophages from 75 Salmonella genomes, which represent the 15 most important serovars in the United Kingdom. We analysed the genomes of the intact prophages for the presence of virulence factors which were associated with; diversity, evolution and pathogenicity of Salmonella and to establish their genomic relationships. We identified 615 prophage elements from the Salmonella genomes, from which 195 prophages are intact, 332 being incomplete while 88 are questionable. The average prophage carriage was found to be more prevalent in S. Heidelberg, S. Inverness and S. Newport (10.2-11.6 prophages/strain), compared to S. Infantis, S. Stanley, S. Typhimurium and S. Virchow (8.2-9 prophages/strain) and S. Agona, S. Braenderup, S. Bovismorbificans, S. Choleraesuis, S. Dublin, and S. Java (6-7.8 prophages/strain), and S. Javiana and S. Enteritidis (5.8 prophages/strain). Cumulatively, 2760 virulence factors were detected from the intact prophages and associated with cellular functionality being linked to effector delivery/secretion system (73%), adherence (22%), magnesium uptake (2.7%), resistance to antimicrobial peptides (0.94%), stress/survival (0.4%), exotoxins (0.32%) and antivirulence (0.18%). Close and distant clusters were formed among the prophage genomes suggesting different lineages and associations with bacteriophages of other Enterobacteriaceae. We show that diverse repertoire of Salmonella prophages are associated with numerous virulence factors, and may contribute to diversity, pathogenicity and success of specific serovars
Fleas of fleas: The potential role of bacteriophages in Salmonella diversity and pathogenicity.
Full text linkNon-typhoidal salmonellosis is an important foodborne and zoonotic infection, that causes significant global public health concern. Diverse serovars are multidrug-resistant and encode several virulence indicators, however, little is known on the role prophages play in driving these characteristics. Here, we extracted prophages from 75 Salmonella genomes, which represent the 15 most important serovars in the United Kingdom. We analysed the genomes of the intact prophages for the presence of virulence factors which were associated with; diversity, evolution and pathogenicity of Salmonella and to establish their genomic relationships. We identified 615 prophage elements from the Salmonella genomes, from which 195 prophages are intact, 332 being incomplete while 88 are questionable. The average prophage carriage was found to be more prevalent in S. Heidelberg, S. Inverness and S. Newport (10.2-11.6 prophages/strain), compared to S. Infantis, S. Stanley, S. Typhimurium and S. Virchow (8.2-9 prophages/strain) and S. Agona, S. Braenderup, S. Bovismorbificans, S. Choleraesuis, S. Dublin, and S. Java (6-7.8 prophages/strain), and S. Javiana and S. Enteritidis (5.8 prophages/strain). Cumulatively, 2760 virulence factors were detected from the intact prophages and associated with cellular functionality being linked to effector delivery/secretion system (73%), adherence (22%), magnesium uptake (2.7%), resistance to antimicrobial peptides (0.94%), stress/survival (0.4%), exotoxins (0.32%) and antivirulence (0.18%). Close and distant clusters were formed among the prophage genomes suggesting different lineages and associations with bacteriophages of other Enterobacteriaceae. We show that diverse repertoire of Salmonella prophages are associated with numerous virulence factors, and may contribute to diversity, pathogenicity and success of specific serovars
Harnessing diverse prophages of STEC O157:H7 phage-type 8 for rapid identification of fresh produce-associated STEC strains
No full textThe Shigatoxigenic Escherichia coli (STEC) serotype O157:H7 is a priority foodborne pathogen in humans. STEC strains in the same serotype can be classified according to their susceptibility to lysis by a set of bacterial lytic viruses, bacteriophages, termed phage typing. In many parts of the world the majority of STEC outbreaks are now derived from plant-based food, with an apparent association of phage-type (PT) 8 strains. Thus, rapid and reproducible identification system to supplement existing methods is needed for these strains. Here, we took a sequence-based approach to identify specific molecular markers. We identified twenty-five prophages (genome-embedded phages) in a representative STEC O157:H7 serotype, isolate 644-PT8, from lettuce. Seven molecular markers unique to 644-PT8 prophage genes were designed to enable rapid and accurate identification of PT8 strains. These markers had the added benefit of discriminating STEC based on their phage repertoire, allowing for detection STEC strains from additional sources. The markers comprised of primers sets that each produced a unique single amplicon of varying sizes (169, 306, 507, 798,1022, 1855, 2371 bp) from the bacterial host genome, 644-PT8, for a multiplex PCR. The markers showed 100% specificity for E. coli O157:H7 in public databases and clustered other serotype strains into specific clades, using the BLASTn tool. These molecular markers provide a valuable novel diagnostic tool for the identification of isolates in different niches that could enhance STEC surveillance. Future work will focus on creating an easy-to-use pipeline for STEC identification in silico, and test feasibility of adoption from field isolates
Harnessing diverse prophages of STEC O157:H7 phage-type 8 for rapid identification of fresh produce-associated STEC strains
No full textThe Shigatoxigenic Escherichia coli (STEC) serotype O157:H7 is a priority foodborne pathogen in humans. STEC strains in the same serotype can be classified according to their susceptibility to lysis by a set of bacterial lytic viruses, bacteriophages, termed phage typing. In many parts of the world the majority of STEC outbreaks are now derived from plant-based food, with an apparent association of phage-type (PT) 8 strains. Thus, rapid and reproducible identification system to supplement existing methods is needed for these strains. Here, we took a sequence-based approach to identify specific molecular markers. We identified twenty-five prophages (genome-embedded phages) in a representative STEC O157:H7 serotype, isolate 644-PT8, from lettuce. Seven molecular markers unique to 644-PT8 prophage genes were designed to enable rapid and accurate identification of PT8 strains. These markers had the added benefit of discriminating STEC based on their phage repertoire, allowing for detection STEC strains from additional sources. The markers comprised of primers sets that each produced a unique single amplicon of varying sizes (169, 306, 507, 798,1022, 1855, 2371 bp) from the bacterial host genome, 644-PT8, for a multiplex PCR. The markers showed 100% specificity for E. coli O157:H7 in public databases and clustered other serotype strains into specific clades, using the BLASTn tool. These molecular markers provide a valuable novel diagnostic tool for the identification of isolates in different niches that could enhance STEC surveillance. Future work will focus on creating an easy-to-use pipeline for STEC identification in silico, and test feasibility of adoption from field isolates
