A5017138457- Pneumonia and Respiratory Infections
- Bacterial Infections and Vaccines
- Antimicrobial Resistance in Staphylococcus
- Streptococcal Infections and Treatments
- Bacteriophages and microbial interactions
- Bacterial Genetics and Biotechnology
- Antibiotic Resistance in Bacteria
- Respiratory viral infections research
- Tuberculosis Research and Epidemiology
- Mycobacterium research and diagnosis
- Bacterial biofilms and quorum sensing
- Antimicrobial agents and applications
- Antimicrobial Peptides and Activities
- Probiotics and Fermented Foods
- Genomics and Phylogenetic Studies
- Pneumocystis jirovecii pneumonia detection and treatment
- Gut microbiota and health
- Escherichia coli research studies
- Influenza Virus Research Studies
- Immune Response and Inflammation
- RNA and protein synthesis mechanisms
- Clostridium difficile and Clostridium perfringens research
- Infective Endocarditis Diagnosis and Management
- Bacillus and Francisella bacterial research
- Microbial infections and disease research
University of Leicester
2015-2024
University of Bologna
2020-2024
University Hospitals of Leicester NHS Trust
2019-2023
National Health Service
2023
European Society of Clinical Microbiology and Infectious Diseases
2020
University of Siena
2008-2018
Fondazione Audiologica Varese
2015
Azienda Ospedaliera Universitaria Senese
2004-2014
LAM Foundation
2006
Epicentre (South Africa)
2004
Streptococcus pneumoniae is one of the most important causes microbial diseases in humans. The genomes 44 diverse strains S. were analyzed and compared with non-pathogenic streptococci Mitis group. Despite evidence extensive recombination, phylogenetic tree revealed six major lineages. With exception serotype 1, correlated poorly capsular serotype, geographical site isolation disease outcome. distribution dispensable genes - present more than strain but not all was consistent phylogeny,...
The human intestine is densely populated by a microbial consortium whose metabolic activities are influenced by, among others, bifidobacteria. However, the genetic basis of adaptation bifidobacteria to gut poorly understood. Analysis 2,214,650-bp genome Bifidobacterium bifidum PRL2010, strain isolated from infant stool, revealed nutrient-acquisition strategy that targets host-derived glycans, such as those present in mucin. Proteome and transcriptome profiling set chromosomal loci...
Abstract Streptococcus pneumoniae (the pneumococcus) is the world’s foremost bacterial pathogen in both morbidity and mortality. Switching between phenotypic forms (or ‘phases’) that favour asymptomatic carriage or invasive disease was first reported 1933. Here, we show underlying mechanism for such phase variation consists of genetic rearrangements a Type I restriction-modification system (SpnD39III). The generate six alternative specificities with distinct methylation patterns, as defined...
Summary Two main patterns of gene expression Streptococcus pneumoniae were observed during infection in the host by quantitative real time RT‐PCR; one was characteristic bacteria blood and tissue, such as brain lung. Gene characterized increased pneumolysin, pspA hrcA , while pneumococci tissue showed neuraminidases, metalloproteinases, oxidative stress competence genes. In vitro situations with similar detected liquid culture a newly developed pneumococcal model biofilm respectively. The...
ABSTRACT We developed a novel surface display system based on the use of bacterial spores. A protein Bacillus subtilis spore coat, CotB, was found to be located and used as fusion partner express 459-amino-acid C-terminal fragment tetanus toxin (TTFC). Western, dot blot fluorescent-activated cell sorting analyses were monitor TTFC expression purified estimated that more than 1.5 × 10 3 molecules exposed each recognized by TTFC-specific antibodies. The efficient presentation heterologous...
To date there are no clear criteria to determine whether a microbe is susceptible biocides or not. As starting point for distinguishing between wild-type and resistant organisms, we set out the minimal inhibitory concentration (MIC) bactericidal (MBC) distributions four common biocides; triclosan, benzalkonium chloride, chlorhexidine sodium hypochlorite 3319 clinical isolates, with particular focus on Staphylococcus aureus (N = 1635) Salmonella spp. 901) but also including Escherichia coli...
Bifidobacteria, one of the relatively dominant components human intestinal microbiota, are considered key groups beneficial bacteria (probiotic bacteria). However, in addition to health-promoting taxa, genus Bifidobacterium also includes dentium, an opportunistic cariogenic pathogen. The genetic basis for ability B. dentium survive oral cavity and contribute caries development is not understood. genome Bd1, a strain isolated from dental caries, was sequenced completion uncover single...
The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota humans and one most important invasive pathogens. A genomic survey allowed establishing occurrence twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, sodium∶solute symporter a permease, underlining an exceptionally high capacity for substrates. Despite variability, combined phenotypic analysis twenty sequenced strains did assign substrate specificity only to two...
The correlation between carbohydrate availability, pneumococcal biofilm formation, nasopharyngeal colonization, and invasion of the host has been investigated. Of a series sugars, only sialic acid (i.e., N-acetylneuraminic acid) enhanced formation in vitro, at concentrations similar to those free human saliva. In murine model carriage, intranasal inoculation significantly increased counts nasopharynx instigated translocation pneumococci lungs. Competition both acid-dependent phenotypes was...
Multidrug-resistant (MDR) Mycobacterium tuberculosis complex (MTBC) strains represent a major threat for (TB) control. Treatment of MDR-TB patients is long and less effective, resulting in significant number treatment failures. The development further resistances leads to extensively drug-resistant (XDR) variants. However, data on the individual reasons failure, e.g. an induced mutational burst, evolution bacteria patient are only sparsely available. To address this question, we investigated...
ABSTRACT During infection, Streptococcus pneumoniae exists mainly in sessile biofilms rather than planktonic form, except during sepsis. The capacity to form is believed be important for nasopharyngeal colonization as well disease pathogenesis, but relatively little known about the regulation of this process. Here, we investigated effect exogenous iron [Fe(III)] role luxS (encoding S-ribosylhomocysteine lyase) on biofilm formation by S. D39. Fe(III) strongly enhanced at concentrations ≥50...
ABSTRACT The MICs and minimum bactericidal concentrations (MBCs) for the biocides benzalkonium chloride chlorhexidine were determined against 1,602 clinical isolates of Staphylococcus aureus . Both compounds showed unimodal MIC MBC distributions (2 4 or 8 mg/liter, respectively) with no apparent subpopulation reduced susceptibility. To investigate further, all screened qac genes, 39 these also had promoter region NorA multidrug-resistant (MDR) efflux pump sequenced. presence qacA , qacB qacC...
We have developed a system in which foreign antigen replaces nearly all of the surface-exposed region fibrillar M protein from Streptococcus pyogenes and is fused to C-terminal attachment motif molecule. The fusion thus expressed on surface gordonii, commensal organism oral cavity. chosen be within context M6 molecule was E7 (98 amino acids) human papillomavirus type 16. Stable recombinant streptococci were obtained by integrating genetic constructs into chromosome, exploiting vivo...
Streptococcus penumoniae is a major human pathogen responsible for respiratory tract infections, septicemia, and meningitis continues to produce numerous cases of disease with relatively high mortalities. S. pneumoniae encodes up three sialidases, NanA, NanB, NanC, that have been implicated in pathogenesis are potential drug targets. NanA has shown be promiscuous sialidase, hydrolyzing the removal Neu5Ac from variety glycoconjugates retention configuration at anomeric center, as we confirm...
The widely used biocide triclosan selectively targets FabI, the NADH-dependent trans-2-enoyl-acyl carrier protein reductase, which is an important target for narrow-spectrum antimicrobial drug development. In relation to growing concern about resistance, we compared in vitro mutants and clinical isolates of Staphylococcus aureus with reduced susceptibility. Clinical S. as well laboratory-generated were assayed minimum inhibitory concentration (MIC) bactericidal (MBC) phenotypes genotypes...
Systemic infection with Streptococcus pneumoniae was investigated in male and female mice models of invasive pneumonia sepsis. Male were found to be more susceptible infection, exhibiting greater weight loss, marked decrease body temperature, a significantly higher mortality rate compared mice. For pneumonia, there significant differences survival rates. Female cleared their lung infections over time, whereas mice, had increased numbers colony-forming units early stages accompanied by levels...
Communication between bacterial cells is crucial for the coordination of diverse cellular processes that facilitate environmental adaptation and, in case pathogenic species, virulence. This achieved by secretion and detection small signaling molecules called autoinducers, a process termed quorum sensing. To date, only molecule recognized both Gram-positive Gram-negative bacteria autoinducer 2 (AI-2), synthesized metabolic enzyme LuxS (S-ribosylhomocysteine lyase) as by-product activated...
The pathogenesis of bacteraemia after challenge with one million pneumococci three isogenic variants was investigated. Sequential analyses blood samples indicated that most episodes were monoclonal events providing compelling evidence for a single bacterial cell bottleneck at the origin invasive disease. With respect to host determinants, results identified novel properties splenic macrophages and role neutrophils in early clearance pneumococci. Concerning microbial factors, whole genome...
Many encapsulated bacteria use capsules to cause invasive diseases. However, it remains largely unknown how the enhance bacterial virulence under in vivo infection conditions. Here we show that primarily target liver survival at onset of blood-borne infections. In a mouse sepsis model, enabled human pathogens Streptococcus pneumoniae and Escherichia coli circumvent recognition liver-resident macrophage Kupffer cells (KCs) capsular serotype-dependent manner. contrast effective capture...