Yannick DN Tremblay

University of Saskatchewan | U of S · Department of Microbiology and Immunology

Actinobacillus pleuropneumoniae is a Gram-negative bacterium and a member of the Pasteurellaceae family. This bacterium is the causative agent of porcine pleuropneumonia, which is a highly contagious respiratory disease causing important economical losses to the worldwide pig industry. It has been shown that A. pleuropneumoniae can form biofilms on...

Biofilm formation and host-pathogen interactions are frequently studied using multiwell plates; however, these closed systems lack shear force which is present at several sites in the host such as the intestinal and urinary tracts. Recently, microfluidic systems, which incorporate shear force and very small volumes, have been developed to provide c...

Actinobacillus pleuropneumoniae causes porcine pleuropneumonia and forms biofilms in vitro on abiotic surfaces; however, presence of biofilms during infections has not been documented. The aim of this study was to use a species-specific fluorescent oligonucleotide probe and confocal microscopy to localize A. pleuropneumoniae in the lungs of two nat...

Clostridioides difficile infections are associated with gut microbiome dysbiosis and are the leading cause of hospital-acquired diarrhoea. The infectious process is strongly influenced by the microbiota and successful infection relies on the absence of specific microbiota-produced metabolites. Deoxycholate and short-chain fatty acids are microbiota...

The ability of bacterial pathogens to establish recurrent and persistent infections is frequently associated with their ability to form biofilms. Clostridioides difficile infections have a high rate of recurrence and relapses and it is hypothesized that biofilms are involved in its pathogenicity and persistence. Biofilm formation by C. difficile is...

The ability of bacterial pathogens to establish recurrent and persistent infections is frequently associated with their ability to form biofilms. Clostridioides difficile infections have a high rate of recurrence and relapses and it is hypothesised that biofilms are involved in its pathogenicity and persistence. Biofilm formation by C. difficile is...

To colonize the host and cause disease, the human enteropathogen Clostridioides difficile must sense, respond, and adapt to the harsh environment of the gastrointestinal tract. We showed that the production and degradation of cyclic diadenosine monophosphate (c-di-AMP) were necessary during different phases of C. difficile growth, environmental ada...

Clostridioides difficile is an opportunistic pathogen that causes by a high rate of recurrent infections. Persistence in the gastrointestinal tract is thought to be mediated by sporulation and/or biofilm formation. There is an increase interest in C. difficile biofilm formation and recent findings have provided a framework to model surface-attached...

The microbiota inhabiting the intestinal tract provide several critical functions to its host. Microorganisms found at the mucosal layer form organized three-dimensional structures which are considered to be biofilms. Their development and functions are influenced by host factors, host-microbe interactions, and microbe-microbe interactions. These s...

To cause disease, the important human enteropathogen Clostridioides difficile must colonize the gastro-intestinal tract but little is known on how this organism senses and responds to the harsh host environment to adapt and multiply. Nucleotide second messengers are signaling molecules used by bacteria to respond to changing environmental condition...

Introduction Microorganisms can develop into a social organization known as biofilms and these communities can be found in virtually all types of environment on earth. In biofilms, cells grow as multicellular communities held together by a self-produced extracellular matrix. Living within a biofilm allows for the emergence of specific properties fo...

Clostridioides difficile infections are associated with gut microbiome dysbiosis and are the leading cause of hospital acquired diarrhoea. The infectious process is strongly influenced by the microbiota and successful infection relies on the absence of specific microbiota-produced metabolites. Deoxycholic acid (DOC) and short chain fatty acids are...

Clostridium difficile is the leading cause of antibiotic-associated diarrhea in adults. During infection, C. difficile must detect the host environment and induce an appropriate survival strategy. Signal transduction networks involving serine/threonine kinases (STKs) play key roles in adaptation, as they regulate numerous physiological processes. P...

Clostridium difficile is a major cause of nosocomial infections. Bacterial persistence in the gut is responsible for infection relapse; sporulation and other unidentified mechanisms contribute to this process. Intestinal bile salts cholate and deoxycholate stimulate spore germination, while deoxycholate kills vegetative cells. Here, we report that...

Actinobacillus pleuropneumoniae is a Gram-negative bacterium that belongs to the family Pasteurellaceae . It is the causative agent of porcine pleuropneumonia, a highly contagious respiratory disease that is responsible for major economic losses in the global pork industry. The disease may present itself as a chronic or an acute infection character...

Coagulase-negative staphylococci (CNS) are considered to be commensal bacteria in humans and animals, but are now also recognized as etiological agents in several infections, including bovine mastitis. Biofilm formation appears to be an important factor in CNS pathogenicity. Furthermore, some researchers have proposed that CNS colonization of the i...

Mastitis affects the health and welfare of dairy cows worldwide. Coagulase-negative staphylococci (CNS) are known to form biofilms and are increasingly recognized as a cause of persistent bovine intramammary infections. A total of 90 CNS isolated from cows with clinical and subclinical mastitis in Argentina from 2008-2014 were identified by PCR-RFL...

Background Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, which causes important worldwide economic losses in the swine industry. Several respiratory tract infections are associated with biofilm formation, and A. pleuropneumoniae has the ability to form biofilms in vitro. Biofilms are structured commun...

Forming biofilms may be a survival strategy of Shiga toxin-producing Escherichia coli to enable it to persist in the environment and the food industry. Here we evaluate and characterize the biofilm forming ability of 39 isolates of Shiga toxin-producing Escherichia coli recovered from human infection and belonging to seropathotypes A, B or C. The p...

Actinobacillus pleuropneumoniae is a Gram-negative bacterium belonging to the Pasteurellaceae family and the causative agent of porcine pleuropneumonia, a highly contagious lung disease causing important economic losses. Surface polysaccharides, including lipopolysaccharides (LPS) and capsular polysaccharides (CPS), are implicated in the adhesion a...

Actinobacillus pleuropneumoniae is a Gram-negative bacterium and causative agent of porcine pleuropneumonia. This is a highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in swine production and these antibiotics are associated with high systemic clearance and low oral bi...

Haemophilus parasuis is a commensal bacterium of the upper respiratory tract of healthy pigs. It is also the etiological agent of Glässer’s disease, a systemic disease characterized by polyarthritis, fibrinous polyserositis and meningitis, which causes high morbidity and mortality in piglets. The aim of this study was to evaluate biofilm formation...

Escherichia coli is a heterogeneous species that can be part of the normal flora of humans but also include strains of medical importance. Among pathogenic members, Shiga-toxin producing E. coli (STEC) are some of the more prominent pathogenic E. coli within the public sphere. STEC disease outbreaks are typically associated with contaminated beef,...

Coagulase-negative staphylococci (CNS) have traditionally been considered minor mastitis pathogens and are the bacteria most frequently isolated from intramammary infection. Previously, our laboratory demonstrated that a majority of CNS isolated from Canadian milk were able to form biofilm and this was strongly and positively associated with days i...

Bacterial biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that is attached to a surface. Biofilms protect and allow bacteria to survive and thrive in hostile environments. Bacteria within biofilms can withstand host immune responses, and are much less susceptible to antibiotics and disinfectants whe...

Bacterial biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that is attached to a surface. Biofilms protect and allow bacteria to survive and thrive in hostile environments. Bacteria within biofilms can withstand host immune responses, and are much less susceptible to antibiotics and disinfectants whe...

Résumé Les biofilms bactériens sont des amas structurés de cellules bactériennes enrobés d’une matrice polymérique et attachés à une surface. Le biofilm protège les bactéries et leur permet de survivre dans des conditions environnementales hostiles. Les bactéries du biofilm peuvent résister à la réponse immunitaire de l’hôte et sont beaucoup plus r...

Background Actinobacillus pleuropneumoniae is the Gram-negative bacterium responsible for porcine pleuropneumonia. This respiratory infection is highly contagious and characterized by high morbidity and mortality. The objectives of our study were to study the transcriptome of A. pleuropneumoniae biofilms at different stages and to develop a protoco...

Aims: Biofilm formation is important for the persistence of bacteria in hostile environments. Bacteria in a biofilm are usually more resistant to antibiotics and disinfectants than planktonic bacteria. Our laboratory previously reported that low concentrations of zinc inhibit biofilm formation of Actinobacillus pleuropneumoniae. The aim of this st...

Actinobacillus pleuropneumoniae (App) is the aetiological agent of porcine pleuropneumonia and is normally transmitted by aerosols and direct contact between animals. App has traditionally been considered an obligate pathogen of pigs and its presence in the environment has yet to be investigated. Here, the presence of App was detected in drinking w...

Mastitis is the most common and detrimental infection of the mammary gland in dairy cows and has a major economic impact on the production of milk and dairy products. Bacterial mastitis is caused by several pathogens, and the most frequently isolated bacterial species are coagulase-negative staphylocci (CNS). Although CNS are considered minor masti...

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, a severe and highly contagious respiratory disease responsible for economic losses in the swine industry worldwide. Although antimicrobial resistance in A. pleuropneumoniae has been recently reported in different countries, the current situation in Canada is unknown....

Actinobacillus pleuropneumoniae is a gram-negative bacterium and is the causative agent of swine pleuropneumonia, a highly contagious respiratory disease. Biofilm formation is an important ability possessed by numerous bacterial pathogens. The purpose of this study was to identify and characterize biofilm mutants of A. pleuropneumoniae serotype 1 s...

Bacterial biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that is attached to a surface. Biofilms protect and allow bacteria to survive and thrive in hostile environments. Bacteria within biofilms can withstand host immune responses, and are much less susceptible to antibiotics and disinfectants whe...

As an inhabitant of the human oral cavity, Streptococcus mutans faces frequent environmental changes. Two-component regulatory systems (TCSs) play a critical role in responding to these changes. Recently, an essential TCS, VicRKX, has been identified. The objective of this study was to identify the environmental signal and bacterial factors regulat...

Histophilus somni is an important pathogen of cattle and sheep. H. somni requires iron and can use ruminant transferrins as iron sources for growth. Here, we investigated the abilities of bovine (strains 649 and 2,336) and ovine (strains 9L and 3384Y) isolates of H. somni to acquire iron from haemoglobins. Using growth assays, the bovine isolates w...