Co-culturing with alters transcriptome when exposed to tonsillar cells.

Introduction: Improved understanding of throat colonization in the presence of other co-existing microbes is important for mapping adaptation to the human throat, and recurrence of infection. Here, we explore the responses triggered by the encounter between two common throat bacteria, and , to identify genes in that are important for colonization in the presence of human tonsillar epithelial cells and , and further compare this transcriptome with the genes expressed in as only bacterium.

Methods: We performed an co-culture experiment followed by RNA sequencing to identify interaction-induced transcriptional alterations and differentially expressed genes (DEGs), followed by gene enrichment analysis.

Exploring differentially expressed genes of Staphylococcus aureus exposed to human tonsillar cells using RNA sequencing.

Background: The nose and the throat are the most predominant colonizing sites of Staphylococcus aureus, and colonization is a risk factor for infection. Nasal colonization is well described; however, we have limited knowledge about S. aureus throat colonization.

Social network analysis of Staphylococcus aureus carriage in a general youth population.

Objectives: Staphylococcus aureus carriage increases the risk of infection. We used social network analysis to evaluate whether contacts have the same S. aureus genotype indicating direct transmission or whether contagiousness is an indirect effect of contacts sharing the same lifestyle or characteristics.

Shotgun-metagenomics based prediction of antibiotic resistance and virulence determinants in Staphylococcus aureus from periprosthetic tissue on blood culture bottles.

Shotgun-metagenomics may give valuable clinical information beyond the detection of potential pathogen(s). Identification of antimicrobial resistance (AMR), virulence genes and typing directly from clinical samples has been limited due to challenges arising from incomplete genome coverage. We assessed the performance of shotgun-metagenomics on positive blood culture bottles (n = 19) with periprosthetic tissue for typing and prediction of AMR and virulence profiles in Staphylococcus aureus.

Shotgun-Metagenomics on Positive Blood Culture Bottles Inoculated With Prosthetic Joint Tissue: A Proof of Concept Study.

Clinical metagenomics is actively moving from research to clinical laboratories. It has the potential to change the microbial diagnosis of infectious diseases, especially when detection and identification of pathogens can be challenging, such as in prosthetic joint infection (PJI). The application of metagenomic sequencing to periprosthetic joint tissue (PJT) specimens is often challenged by low bacterial load in addition to high level of inhibitor and contaminant host DNA, limiting pathogen recovery.

Culturing periprosthetic tissue in BacT/Alert® Virtuo blood culture system leads to improved and faster detection of prosthetic joint infections.

Background: Blood culture bottles (BCBs) provide a semiautomated method for culturing periprosthetic tissue specimens. A study evaluating BCBs for culturing clinical samples other than body fluids is needed before implementation into clinical practice. Our objective was to evaluate use of the BacT/Alert® Virtuo blood culture system for culturing periprosthetic tissue specimens.

Genetic variability in the sdrD gene in Staphylococcus aureus from healthy nasal carriers.

Background: Staphylococcus aureus cell wall anchored Serine Aspartate repeat containing protein D (SdrD) is a member of the microbial surface component recognising adhesive matrix molecules (MSCRAMMs). It is involved in the bacterial adhesion and virulence. However the extent of genetic variation in S.

Localization of Staphylococcus aureus in tissue from the nasal vestibule in healthy carriers.

Background: Colonization of the body is an important step in Staphylococcus aureus infection. S. aureus colonizes skin and mucous membranes in humans and several animal species.

The interaction between Staphylococcus aureus SdrD and desmoglein 1 is important for adhesion to host cells.

Staphylococcus aureus is known as a frequent colonizer of the skin and mucosa. Among bacterial factors involved in colonization are adhesins such as the microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). Serine aspartate repeat containing protein D (SdrD) is involved in adhesion to human squamous cells isolated from the nose.

A Look into the Melting Pot: The mecC-Harboring Region Is a Recombination Hot Spot in Staphylococcus stepanovicii.

Introduction: Horizontal gene transfer (HGT) is an important driver for resistance- and virulence factor accumulation in pathogenic bacteria such as Staphylococcus aureus.

Methods: Here, we have investigated the downstream region of the bacterial chromosomal attachment site (attB) for the staphylococcal cassette chromosome mec (SCCmec) element of a commensal mecC-positive Staphylococcus stepanovicii strain (IMT28705; ODD4) with respect to genetic composition and indications of HGT. S.

Staphylococcus aureus nasal isolates from healthy individuals cause highly variable host cell responses in vitro: the Tromsø Staph and Skin Study.

Studies on Staphylococcus aureus populations colonizing the nasal cavity reveal that some bacterial strains are more common, while others are rarely found. This study included five isolates with the most common spa types and five isolates with rare spa types from healthy population. Selected phenotypic traits and genomic content among nasal S.

Host- and microbe determinants that may influence the success of S. aureus colonization.

Staphylococcus aureus may cause serious skin and soft tissue infections, deep abscesses, endocarditis, osteomyelitis, pneumonia, and sepsis. S. aureus persistently colonizes 25-30% of the adult human population, and S.

Core genome conservation of Staphylococcus haemolyticus limits sequence based population structure analysis.

The notoriously multi-resistant Staphylococcus haemolyticus is an emerging pathogen causing serious infections in immunocompromised patients. Defining the population structure is important to detect outbreaks and spread of antimicrobial resistant clones. Currently, the standard typing technique is pulsed-field gel electrophoresis (PFGE).

The AmpC phenotype in Norwegian clinical isolates of Escherichia coli is associated with an acquired ISEcp1-like ampC element or hyperproduction of the endogenous AmpC.

Objectives: The aim of the study was to examine resistance mechanisms associated with an AmpC phenotype in Norwegian clinical isolates of Escherichia coli.

Methods: Clinical E. coli isolates (n = 106) with reduced susceptibility to third-generation cephalosporins without clavulanic acid synergy were collected from 12 Norwegian laboratories from 2003 to 2005.

Methicillin-resistant Staphylococcus aureus (MRSA) isolated from small and exotic animals at a university hospital during routine microbiological examinations.

Clinical specimens of small animals (n=869) were screened for the occurrence of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA; MRSA) during routine microbiological examinations, and results were confirmed by a multiplex PCR strategy. The genetic relatedness of all mecA-positive S. aureus isolates was further investigated by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), PCR for Panton-Valentine leukocidine genes (PVL) and staphylococcal cassette chromosome mec-typing (SCCmec).

Multiple staphylococcal cassette chromosomes and allelic variants of cassette chromosome recombinases in Staphylococcus aureus and coagulase-negative staphylococci from Norway.

We investigated the nature of the staphylococcal cassette chromosome mec (SCCmec) elements and cognate insertion sites in a collection of 42 clinical staphylococcal isolates of various species from Norway. The ccr and mec genes and the attachment sites (attL/attR) were identified by PCR, Southern blot hybridization, and DNA sequencing. We found 10 possibly new SCCmec types and one previously unreported variant of SCCmec type III (mec complex A, ccrAB3, and ccrC7) in Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus hominis.

SCCmec in staphylococci: genes on the move.

Staphylococcal cassette chromosome (SCC) elements are, so far, the only vectors described for the mecA gene encoding methicillin resistance in staphylococci. SCCmec elements are classified according to the type of recombinase they carry and their general genetic composition. SCCmec types I-V have been described, and SCC elements lacking mecA have also been reported.

Dissemination of community-acquired methicillin-resistant Staphylococcus aureus clones in northern Norway: sequence types 8 and 80 predominate.

Increasing frequencies of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) strain isolation have been reported from many countries. The overall prevalence of MRSA in Norway is still very low. MRSA isolates (n = 67) detected between 1995 and 2003 in northern Norway were analyzed by pulsed-field gel electrophoresis, multilocus sequence typing, and staphylococcal cassette chromosome mec (SCCmec) typing.

Local variants of Staphylococcal cassette chromosome mec in sporadic methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative Staphylococci: evidence of horizontal gene transfer?

The mecA gene in Staphylococcus aureus is located on the genetic element staphylococcal cassette chromosome (SCC). Different SCCmecs have been classified according to their putative recombinase genes (ccrA and ccrB) and overall genetic composition. Clinical isolates of coagulase-negative staphylococci (CoNS; n = 39) and S.