Ribosomal Mutations Conferring Macrolide Resistance in Legionella pneumophila.

Monitoring the emergence of antibiotic resistance is a recent issue in the treatment of Legionnaires' disease. Macrolides are recommended as first-line therapy, but resistance mechanisms have not been studied in species. Our aim was to determine the molecular basis of macrolide resistance in Twelve independent lineages from a common susceptible ancestral strain were propagated under conditions of erythromycin or azithromycin pressure to produce high-level macrolide resistance.

Molecular diversity and high virulence of Legionella pneumophila strains isolated from biofilms developed within a warm spring of a thermal spa.

Background: Several cases of legionellosis have been diagnosed in the same French thermal spa in 1986, 1994 and 1997. L. pneumophila serogroup 1 (Lp1) strains have been isolated from several patients, but the source of contamination was not identified despite the presence of different Lp1 in water samples of the three natural springs feeding the spa at this period.

Progress in the surveillance and control of Legionella infection in France, 1998-2008.

Background: In France, the notification of Legionnaires' disease (LD) has been mandatory since 1987. Following a study showing an important under-reporting of the disease, the surveillance system was strengthened in 1997: the urinary antigen detection test was introduced as a new diagnostic tool and guidelines for prevention and control of the disease were implemented. After these measures, the incidence of LD increased gradually, reaching 2.

Host-related risk factors and clinical features of community-acquired legionnaires disease due to the Paris and Lorraine endemic strains, 1998-2007, France.

Background: In France, Legionnaires disease is mainly caused by Legionella pneumophila. Here, we investigated possible host factors associated with susceptibility to community-acquired Legionnaires disease caused by the endemic Paris and Lorraine strains.

Methods: We conducted a double-nested exploratory case-control study with use of data from the French national surveillance network of incident Legionnaires disease cases notified from 1998 through 2007.

Evaluation of a nested-PCR-derived sequence-based typing method applied directly to respiratory samples from patients with Legionnaires' disease.

Sequence-based typing (SBT) is a powerful method based on the sequencing of seven genes of Legionella pneumophila isolates. SBT performed directly on clinical samples has been used only in a limited number of cases. In our study, its efficiency was tested with 63 legionellosis respiratory samples.

[Legionnaires disease].

Legionnaires disease, more formally known as legionellosis, is a relatively common form of severe pneumonia caused by Legionella, a genus of waterborne bacteria. Legionellosis is acquired by inhalation of legionellae from contaminated environmental sources. Legionella pneumophila serogroup 1 is responsible for more than 80% of cases in most countries.

Toxin gene content of the Lyon methicillin-resistant Staphylococcus aureus clone compared with that of other pandemic clones.

The methicillin-resistant Staphylococcus aureus (MRSA) Lyon clone, detected throughout France, contains the enterotoxin A gene (sea), like other pandemic clones of clonal complex 8 (CC8). The egc locus was detected in MRSA pandemic clones of CC5, CC22, and CC45, occasionally with the toxic shock syndrome toxin 1 gene. The representative strain of the EMRSA-16 clone (CC30) harbored both sea and the egc locus.

Characterization of the Legionella anisa population structure by pulsed-field gel electrophoresis.

We analysed 38 French isolates of Legionella anisa by means of pulsed-field gel electrophoresis (PFGE) with single or double digestion. Double digestion was more discriminatory than single digestion, and can thus be useful for epidemiological studies of L. anisa.

Detection of new methicillin-resistant Staphylococcus aureus clones containing the toxic shock syndrome toxin 1 gene responsible for hospital- and community-acquired infections in France.

Methicillin-resistant Staphylococcus aureus (MRSA) clones harboring the toxic shock syndrome toxin 1 (tst) gene have been detected in France and in Switzerland since 2002. During a passive survey conducted between 2002 and 2003, we collected 103 tst-positive S. aureus isolates from 42 towns in France, of which 27 were resistant to methicillin.

Detection of methicillin-resistant Staphylococcus aureus strains resistant to multiple antibiotics and carrying the Panton-Valentine leukocidin genes in an Algiers hospital.

Forty-five Panton-Valentine leukocidin (PVL)-positive, methicillin-resistant Staphylococcus aureus strains were isolated in Algeria between 2003 and 2004; 18 isolates were isolated in the community and 27 in a hospital. Five PVL-positive hospital isolates were resistant to multiple antibiotics, including ofloxacin and gentamicin for three isolates.

Clinical and environmental isolates of Legionella pneumophila serogroup 1 cannot be distinguished by sequence analysis of two surface protein genes and three housekeeping genes.

We used gene sequencing to determine whether clinical (sporadic, epidemic, and endemic) and environmental isolates of Legionella pneumophila serogroup (sg) 1 belong to specific lineages. A total of 178 clinical and environmental L. pneumophila sg 1 isolates, defined by pulsed-field gel electrophoresis and epidemiological data as sporadic, epidemic, or endemic, were analyzed for polymorphisms in five gene fragments.

Legionella pneumophila serogroup 1 strain Paris: endemic distribution throughout France.

An analysis of 691 French clinical Legionella isolates showed that the endemic L. pneumophila serogroup 1 strain Paris was responsible for 12.2% of all cases of legionellosis and had a specific pulsed-field gel electrophoresis pattern.

Relationships between Staphylococcus aureus genetic background, virulence factors, agr groups (alleles), and human disease.

The expression of most Staphylococcus aureus virulence factors is controlled by the agr locus, which encodes a two-component signaling pathway whose activating ligand is an agr-encoded autoinducing peptide (AIP). A polymorphism in the amino acid sequence of the AIP and of its corresponding receptor divides S. aureus strains into four major groups.