Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-7 (of 7 Records) |
Query Trace: Pickard S[original query] |
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Functional analysis of colonization factor antigen I positive enterotoxigenic Escherichia coli identifies genes implicated in survival in water and host colonization.
Abd El Ghany M , Barquist L , Clare S , Brandt C , Mayho M , Joffre E , Sjöling Å , Turner AK , Klena JD , Kingsley RA , Hill-Cawthorne GA , Dougan G , Pickard D . Microb Genom 2021 7 (6) Enterotoxigenic Escherichia coli (ETEC) expressing the colonization pili CFA/I are common causes of diarrhoeal infections in humans. Here, we use a combination of transposon mutagenesis and transcriptomic analysis to identify genes and pathways that contribute to ETEC persistence in water environments and colonization of a mammalian host. ETEC persisting in water exhibit a distinct RNA expression profile from those growing in richer media. Multiple pathways were identified that contribute to water survival, including lipopolysaccharide biosynthesis and stress response regulons. The analysis also indicated that ETEC growing in vivo in mice encounter a bottleneck driving down the diversity of colonizing ETEC populations. |
Molecular Surveillance Identifies Multiple Transmissions of Typhoid in West Africa.
Wong VK , Holt KE , Okoro C , Baker S , Pickard DJ , Marks F , Page AJ , Olanipekun G , Munir H , Alter R , Fey PD , Feasey NA , Weill FX , Le Hello S , Hart PJ , Kariuki S , Breiman RF , Gordon MA , Heyderman RS , Jacobs J , Lunguya O , Msefula C , MacLennan CA , Keddy KH , Smith AM , Onsare RS , De Pinna E , Nair S , Amos B , Dougan G , Obaro S . PLoS Negl Trop Dis 2016 10 (9) e0004781 BACKGROUND: The burden of typhoid in sub-Saharan African (SSA) countries has been difficult to estimate, in part, due to suboptimal laboratory diagnostics. However, surveillance blood cultures at two sites in Nigeria have identified typhoid associated with Salmonella enterica serovar Typhi (S. Typhi) as an important cause of bacteremia in children. METHODS: A total of 128 S. Typhi isolates from these studies in Nigeria were whole-genome sequenced, and the resulting data was used to place these Nigerian isolates into a worldwide context based on their phylogeny and carriage of molecular determinants of antibiotic resistance. RESULTS: Several distinct S. Typhi genotypes were identified in Nigeria that were related to other clusters of S. Typhi isolates from north, west and central regions of Africa. The rapidly expanding S. Typhi clade 4.3.1 (H58) previously associated with multiple antimicrobial resistances in Asia and in east, central and southern Africa, was not detected in this study. However, antimicrobial resistance was common amongst the Nigerian isolates and was associated with several plasmids, including the IncHI1 plasmid commonly associated with S. Typhi. CONCLUSIONS: These data indicate that typhoid in Nigeria was established through multiple independent introductions into the country, with evidence of regional spread. MDR typhoid appears to be evolving independently of the haplotype H58 found in other typhoid endemic countries. This study highlights an urgent need for routine surveillance to monitor the epidemiology of typhoid and evolution of antimicrobial resistance within the bacterial population as a means to facilitate public health interventions to reduce the substantial morbidity and mortality of typhoid. |
Evolution of atypical enteropathogenic E. coli by repeated acquisition of LEE pathogenicity island variants
Ingle DJ , Tauschek M , Edwards DJ , Hocking DM , Pickard DJ , Azzopardi KI , Amarasena T , Bennett-Wood V , Pearson JS , Tamboura B , Antonio M , Ochieng JB , Oundo J , Mandomando I , Qureshi S , Ramamurthy T , Hossain A , Kotloff KL , Nataro JP , Dougan G , Levine MM , Robins-Browne RM , Holt KE . Nat Microbiol 2016 1 15010 Atypical enteropathogenic Escherichia coli (aEPEC) is an umbrella term given to E. coli that possess a type III secretion system encoded in the locus of enterocyte effacement (LEE), but lack the virulence factors (stx, bfpA) that characterize enterohaemorrhagic E. coli and typical EPEC, respectively. The burden of disease caused by aEPEC has recently increased in industrialized and developing nations, yet the population structure and virulence profile of this emerging pathogen are poorly understood. Here, we generated whole-genome sequences of 185 aEPEC isolates collected during the Global Enteric Multicenter Study from seven study sites in Asia and Africa, and compared them with publicly available E. coli genomes. Phylogenomic analysis revealed ten distinct widely distributed aEPEC clones. Analysis of genetic variation in the LEE pathogenicity island identified 30 distinct LEE subtypes divided into three major lineages. Each LEE lineage demonstrated a preferred chromosomal insertion site and different complements of non-LEE encoded effector genes, indicating distinct patterns of evolution of these lineages. This study provides the first detailed genomic framework for aEPEC in the context of the EPEC pathotype and will facilitate further studies into the epidemiology and pathogenicity of EPEC by enabling the detection and tracking of specific clones and LEE variants. |
Genomic and Phenotypic Analysis Reveal the Emergence of an Atypical Salmonella Senftenberg Variant in China.
Abd El Ghany M , Shi X , Li Y , Ansari HR , Hill-Cawthorne GA , Ho YS , Naeem R , Pickard D , Klena JD , Xu X , Pain A , Hu Q . J Clin Microbiol 2016 54 (8) 2014-22 Human infections with Salmonella enterica subspecies enterica serovar Senftenberg are often associated with exposure to poultry flocks, farm environments or contaminated food. The recent emergence of multidrug-resistant isolates has raised public health concerns. In this study comparative genomics and phenotypic analysis were used to characterize 14 clinical Salmonella Senftenberg isolates recovered from multiple outbreaks in Shenzhen and Shanghai, China between 2002 and 2011. Single nucleotide polymorphism analyses identified two phylogenetically distinct clades of S. Senftenberg, designated SC1 and SC2, harboring variations in Salmonella Pathogenicity Island-1 and 2 and exhibiting distinct biochemical and phenotypic signatures. Although both variants shared an identical serotype, the SC2 isolates of sequence type-14 (ST14) harbored intact SPI-1 and 2 and hence were characterized by possessing efficient invasion capabilities. In contrast, the SC1 isolates had structural deletion patterns in both SPI-1 and 2 that correlated with an impaired capacity to invade human cultured cells and also the year of their isolation. These atypical SC1 isolates also lacked the capacity to produce hydrogen sulfide. These findings highlight the emergence of atypical Salmonella Senftenberg variants in China and provide genetic validation that variants lacking SPI-1and regions of SPI-2, leading to impaired invasion capacity, can still cause clinical disease. These data have identified an emerging public health concern and highlight the need to strengthen surveillance to detect the prevalence and transmission of non-Typhoidal Salmonella species. |
Phylogeographical analysis of the dominant multidrug-resistant H58 clade of Salmonella Typhi identifies inter- and intracontinental transmission events.
Wong VK , Baker S , Pickard DJ , Parkhill J , Page AJ , Feasey NA , Kingsley RA , Thomson NR , Keane JA , Weill FX , Edwards DJ , Hawkey J , Harris SR , Mather AE , Cain AK , Hadfield J , Hart PJ , Thieu NT , Klemm EJ , Glinos DA , Breiman RF , Watson CH , Kariuki S , Gordon MA , Heyderman RS , Okoro C , Jacobs J , Lunguya O , Edmunds WJ , Msefula C , Chabalgoity JA , Kama M , Jenkins K , Dutta S , Marks F , Campos J , Thompson C , Obaro S , MacLennan CA , Dolecek C , Keddy KH , Smith AM , Parry CM , Karkey A , Mulholland EK , Campbell JI , Dongol S , Basnyat B , Dufour M , Bandaranayake D , Naseri TT , Singh SP , Hatta M , Newton P , Onsare RS , Isaia L , Dance D , Davong V , Thwaites G , Wijedoru L , Crump JA , De Pinna E , Nair S , Nilles EJ , Thanh DP , Turner P , Soeng S , Valcanis M , Powling J , Dimovski K , Hogg G , Farrar J , Holt KE , Dougan G . Nat Genet 2015 47 (6) 632-9 The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species. |
Critical systems for public health management of floods, North Dakota
Wiedrich TW , Sickler JL , Vossler BL , Pickard SP . J Public Health Manag Pract 2013 19 (3) 259-65 Availability of emergency preparedness funding between 2002 and 2009 allowed the North Dakota Department of Health to build public health response capabilities. Five of the 15 public health preparedness capability areas identified by the Centers for Disease Control and Prevention in 2011 have been thoroughly tested by responses to flooding in North Dakota in 2009, 2010, and 2011; those capability areas are information sharing, emergency operations coordination, medical surge, material management and distribution, and volunteer management. Increasing response effectiveness has depended on planning, implementation of new information technology, changes to command and control procedures, containerized response materials, and rapid contract procedures. Continued improvement in response and maintenance of response capabilities is dependent on ongoing funding. |
Hunting with lead: association between blood lead levels and wild game consumption
Iqbal S , Blumenthal W , Kennedy C , Yip FY , Pickard S , Flanders WD , Loringer K , Kruger K , Caldwell KL , Jean Brown M . Environ Res 2009 109 (8) 952-9 BACKGROUND: Wild game hunting is a popular activity in many regions of the United States. Recently, the presence of lead fragments in wild game meat, presumably from the bullets or shot used for hunting, has raised concerns about health risks from meat consumption. OBJECTIVE: This study examined the association between blood lead levels (PbB) and wild game consumption. METHODS: We recruited 742 participants, aged 2-92 years, from six North Dakota cities. Blood lead samples were collected from 736 persons. Information on socio-demographic background, housing, lead exposure source, and types of wild game consumption (i.e., venison, other game such as moose, birds) was also collected. Generalized estimating equations (GEE) were used to determine the association between PbB and wild game consumption. RESULTS: Most participants reported consuming wild game (80.8%) obtained from hunting (98.8%). The geometric mean PbB were 1.27 and 0.84mug/dl among persons who did and did not consume wild game, respectively. After adjusting for potential confounders, persons who consumed wild game had 0.30mug/dl (95% confidence interval: 0.16-0.44mug/dl) higher PbB than persons who did not. For all game types, recent (<1 month) wild game consumption was associated with higher PbB. PbB was also higher among those who consumed a larger serving size (≥2oz vs. <2oz); however, this association was significant for 'other game' consumption only. CONCLUSIONS: Participants who consumed wild game had higher PbB than those who did not consume wild game. Careful review of butchering practices and monitoring of meat-packing processes may decrease lead exposure from wild game consumption. |
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