The CJIE1 prophage of Campylobacter jejuni affects protein expression in growth media with and without bile salts

BACKGROUND: The presence of Campylobacter jejuni temperate bacteriophages has increasingly been associated with specific biological effects. It has recently been demonstrated that the presence of the prophage CJIE1 is associated with increased adherence and invasion of C. jejuni isolates in cell culture assays. RESULTS: Quantitative comparative proteomics experiments were undertaken using three closely related isolates with CJIE1 and one isolate without CJIE1 to determine whether there was a corresponding difference in protein expression levels. Initial experiments indicated that about 2% of the total proteins characterized were expressed at different levels in isolates with or without the prophage. Some of these proteins regulated by the presence of CJIE1 were associated with virulence or regulatory functions. Additional experiments were conducted using C. jejuni isolates with and without CJIE1 grown on four different media: Mueller Hinton (MH) media containing blood; MH media containing 0.1% sodium deoxycholate, which is thought to result in increased expression of virulence proteins; MH media containing 2.5% Oxgall; and MHwithout additives. These experiments provided further evidence that CJIE1 affected protein expression, including virulence-associated proteins. They also demonstrated a general bile response involving a majority of the proteome and clearly showed the induction of almost all proteins known to be involved with iron acquisition. The data have been deposited to the ProteomeXchange with identifiers PXD000798, PXD000799, PXD000800, and PXD000801. CONCLUSION: The presence of the CJIE1 prophage was associated with differences in protein expression levels under different conditions. Further work is required to determine what genes are involved in causing this phenomenon

Salmonella enterica serovars associated with bacteremia in Canada, 2006–2019

Background: Members of the bacterial genus Salmonella cause salmonellosis, a disease with a spectrum of clinical presentations from a self-limiting gastroenteritis to more severe bacteremia, organ failure and sepsis. The genus consists of over 2,600 serological variants (serovars). Important differences in the pathogenesis of Salmonella serovars have been noted. Objective: The purpose of this study was to determine which Salmonella serovars were more likely to be associated with bacteremia in Canada. Methods: Information on the total number of Salmonella infections and blood isolations reported to the National Enteric Surveillance Program (NESP) from 2006 to 2019 was extracted for each serovar. The risk (proportion) and likelihood (odds) of bacteremia were calculated for all serovars. Results: Of the 96,082 Salmonella cases reported to the NESP during the 14-year study period, 4.4% (95% CI: 4.3%–4.6%) were bacteremic. Twenty nontyphoidal Salmonella (NTS) serovars were associated with lower rates of bacteremia compared to all NTS serovars, and 19 NTS serovars were identified as having higher rates. Heidelberg, Oranienburg, Schwarzengrund, Virchow, Panama and Poona among the top 25 most commonly reported serovars in Canada during the study period. Conclusion: The identification of serovars associated with Salmonella bacteremia in Canada is a first step towards understanding differences in pathogenesis and disease presentation

Sérovars de Salmonella enterica associés à des bactériémies au Canada, 2006 à 2019

Contexte : Les membres du genre bactérien Salmonella sont à l’origine de la salmonellose, une maladie dont les manifestations cliniques varient d’une gastro-entérite autolimitée à une bactériémie plus grave, une défaillance organique et une septicémie. Le genre se compose de plus de 2 600 variantes sérologiques (sérovars). On a remarqué des différences importantes dans la pathogenèse des sérovars de Salmonella. Objectif : Le but de cette étude était de déterminer quels sérovars de Salmonella étaient plus susceptibles d’être associés à des bactériémies au Canada. Méthodes : Pour chaque sérovar, on a extrait les informations sur le nombre total d’infections à Salmonella et d’isolats sanguins signalés au Programme national de surveillance des maladies entériques de 2006 à 2019. Le risque (proportion) et la probabilité (cote) de bactériémie ont été calculés pour tous les sérovars. Résultats : Sur les 96 082 cas de salmonellose signalés au Programme national de surveillance des maladies entériques pendant la période d’étude de 14 ans, 4,4 % (IC 95 % : 4,3 %–4,6 %) étaient bactériémiques. Vingt sérovars de Salmonella non typhique ont été associés à des taux plus faibles de bactériémie par rapport à tous les sérovars de Salmonella non typhique, et 19 sérovars de Salmonella non typhique ont été identifiés comme ayant des taux plus élevés, Heidelberg, Oranienburg, Schwarzengrund, Virchow, Panama et Poona comptant parmi les 25 sérovars les plus fréquemment signalés au Canada pendant la période d’étude. Conclusion : L’identification des sérovars associés aux bactériémies à Salmonella au Canada est un premier pas vers la compréhension des différences dans la pathogenèse et la présentation de la maladie