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Traore P.,Center hospitalier Sud Essonne | Bourgeois-Nicolaos N.,University Hospital Antoine Beclere | Ruimy R.,University of Nice Sophia Antipolis | Laurent F.,French National Reference Center for Staphylococci | And 4 more authors.
Folia Microbiologica | Year: 2014

For the first time, it was reported in France a cluster of autochthonous severe community-acquired (CA) infections due to the USA300 methicillin-resistant Staphylococcus aureus (MRSA) clone. The three cases belonged to the same family without any identified clue of abroad importation pathway. The domestic spread of USA300 in France is of concern. © 2014, Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i.

Valour F.,French Institute of Health and Medical Research | Valour F.,University of Lyon | Blanc-Pattin V.,University of Lyon | Freydiere A.-M.,University of Lyon | And 8 more authors.
Diagnostic Microbiology and Infectious Disease | Year: 2014

The GeneXpert MRSA/SA SSTI assay was compared to conventional cultures to detect Staphylococcus aureus and methicillin-resistance from 91 bone and joint infection samples. Sensitivity and specificity were 94.4% and 100%. Three false-positive results were observed, in fact providing from patients known to be infected by S. aureus on the basis of other concomitant osteoarticular samples, which suggests that PCR was more sensitive than culture. This diagnosis accuracy may help shorten toxic and non-optimal empirical therapies such as glycopeptides in case of methicillin-susceptible strains. © 2014 Elsevier Inc.

Dermota U.,National Laboratory for Health | Zdovc I.,University of Ljubljana | Strumbelj I.,National Laboratory for Health | Grmek-Kosnik I.,National Laboratory for Health | And 8 more authors.
Epidemiology and Infection | Year: 2015

Following the recognition of a mecC MRSA isolate from a patient hospitalized in the northeastern region of Slovenia, a national collection of 395 community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates from 2006 to 2013 was screened. An additional six mecC MRSA strains were found and characterized as spa types t843, t9397 and t10009, and multilocus sequence type ST130. The low oxacillin minimum inhibitory concentrations and absence of the mecA gene make recognition of these MRSA strains problematical for diagnostic laboratories. In such strains the presence of mecC should be determined. © 2014 Cambridge University Press.

Shambat S.,Indian Institute of Science | Shambat S.,Karolinska University Hospital | Nadig S.,Indian Institute of Science | Prabhakara S.,Indian Institute of Science | And 5 more authors.
BMC Microbiology | Year: 2012

Background: Diseases from Staphylococcus aureus are a major problem in Indian hospitals and recent studies point to infiltration of community associated methicillin resistant S. aureus (CA-MRSA) into hospitals. Although CA-MRSA are genetically different from nosocomial MRSA, the distinction between the two groups is blurring as CA-MRSA are showing multidrug resistance and are endemic in many hospitals. Our survey of samples collected from Indian hospitals between 2004 and 2006 had shown mainly hospital associated methicillin resistant Staphylococcus aureus (HA-MRSA) carrying staphylococcal cassette chromosome mec (SCCmec) type III and IIIA. But S. aureus isolates collected from 2007 onwards from community and hospital settings in India have shown SCCmec type IV and V cassettes while several variations of type IV SCCmec cassettes from IVa to IVj have been found in other parts of the world. In the present study, we have collected nasal swabs from rural and urban healthy carriers and pus, blood etc from in patients from hospitals to study the distribution of SCCmec elements and sequence types (STs) in the community and hospital environment. We performed molecular characterization of all the isolates to determine their lineage and microarray of select isolates from each sequence type to analyze their toxins, virulence and immune-evasion factors. Results: Molecular analyses of 68 S. aureus isolates from in and around Bengaluru and three other Indian cities have been carried out. The chosen isolates fall into fifteen STs with all major clonal complexes (CC) present along with some minor ones. The dominant MRSA clones are ST22 and ST772 among healthy carriers and patients. We are reporting three novel clones, two methicillin sensitive S. aureus (MSSA) isolates belonging to ST291 (related to ST398 which is live stock associated), and two MRSA clones, ST1208 (CC8), and ST672 as emerging clones in this study for the first time. Sixty nine percent of isolates carry Panton- Valentine Leucocidin genes (PVL) along with many other toxins. There is more diversity of STs among methicillin sensitive S. aureus than resistant ones. Microarray analysis of isolates belonging to different STs gives an insight into major toxins, virulence factors, adhesion and immune evasion factors present among the isolates in various parts of India. Conclusions: S. aureus isolates reported in this study belong to a highly diverse group of STs and CC and we are reporting several new STs which have not been reported earlier along with factors influencing virulence and host pathogen interactions. © 2012 Shambat et al.

Valour F.,French Institute of Health and Medical Research | Valour F.,University of Lyon | Trouillet-Assant S.,French Institute of Health and Medical Research | Trouillet-Assant S.,University of Lyon | And 18 more authors.
PLoS ONE | Year: 2013

Background:Staphylococcus epidermidis orthopedic device infections are caused by direct inoculation of commensal flora during surgery and remain rare, although S. epidermidis carriage is likely universal. We wondered whether S. epidermidis orthopedic device infection strains might constitute a sub-population of commensal isolates with specific virulence ability. Biofilm formation and invasion of osteoblasts by S. aureus contribute to bone and joint infection recurrence by protecting bacteria from the host-immune system and most antibiotics. We aimed to determine whether S. epidermidis orthopedic device infection isolates could be distinguished from commensal strains by their ability to invade osteoblasts and form biofilms.Materials and Methods:Orthopedic device infection S. epidermidis strains (n = 15) were compared to nasal carriage isolates (n = 22). Osteoblast invasion was evaluated in an ex vivo infection model using MG63 osteoblastic cells co-cultured for 2 hours with bacteria. Adhesion of S. epidermidis to osteoblasts was explored by a flow cytometric approach, and internalized bacteria were quantified by plating cell lysates after selective killing of extra-cellular bacteria with gentamicin. Early and mature biofilm formations were evaluated by a crystal violet microtitration plate assay and the Biofilm Ring Test method.Results:No difference was observed between commensal and infective strains in their ability to invade osteoblasts (internalization rate 308+/-631 and 347+/-431 CFU/well, respectively). This low internalization rate correlated with a low ability to adhere to osteoblasts. No difference was observed for biofilm formation between the two groups.Conclusion:Osteoblast invasion and biofilm formation levels failed to distinguish S. epidermidis orthopedic device infection strains from commensal isolates. This study provides the first assessment of the interaction between S. epidermidis strains isolated from orthopedic device infections and osteoblasts, and suggests that bone cell invasion is not a major pathophysiological mechanism in S. epidermidis orthopedic device infections, contrary to what is observed for S. aureus. © 2013 Valour et al.

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