Highly Diversified Pandoraea pulmonicola Population during Chronic Colonization in Cystic Fibrosis

Several environmental bacteria are considered as opportunistic pathogens in cystic fibrosis (CF) and are able to persistently colonize the CF respiratory tract (CFRT). Beside Pseudomonas aeruginosa and Burkholderia cepacia complex, Pandoraea spp. are defined as pathogenic. During chronic colonization, adaptive evolution and diversified population have been demonstrated, notably for P. aeruginosa. However, the persistence of Pandoraea in the CFRT remains largely unexplored. We studied genomic and phenotypic traits of Pandoraea pulmonicola isolates successively recovered from the airways of a single CF patient and relate the results to qualitative and quantitative evolution of other cultivable pathogens and to patient clinical status. A total of 31 isolates recovered from 18 sputum samples over a 7-year period in a single CF patient were studied. Genome dynamics was assessed by pulsed-field gel electrophoresis, ERIC-PCR fingerprinting and 16S rRNA gene PCR-temporal temperature gel electrophoresis. Phenotypic features included antimicrobial susceptibility, motility, biofilm production, and virulence in Caenorhabditis elegans model. Variability was observed for all the characteristics studied leading to highly diversified patterns (24 patterns) for the 31 clonally related isolates. Some of these modifications, mainly genomic events were concomitantly observed with CFRT microbiota composition shifts and with severe exacerbations. The diversity of P. pulmonicola population studied, observed for isolates recovered from successive samples but also within a sample suggested that existence of a diversified population may represent a patho-adaptive strategy for host persistence in the heterogeneous and fluctuating CFRT environment

Multilocus sequence typing supports the hypothesis that Ochrobactrum anthropi displays a human-associated subpopulation

<p>Abstract</p> <p>Background</p> <p><it>Ochrobactrum anthropi </it>is a versatile bacterial species with strains living in very diverse habitats. It is increasingly recognized as opportunistic pathogen in hospitalized patients. The population biology of the species particularly with regard to the characteristics of the human isolates is being investigated. To address this issue, we proposed a polyphasic approach consisting in Multi-Locus Sequence Typing (MLST), multi-locus phylogeny, genomic-based fingerprinting by pulsed-field gel electrophoresis (PFGE) and antibiotyping.</p> <p>Results</p> <p>We tested a population of 70 <it>O. anthropi </it>clinical (n = 43) and environmental (n = 24) isolates as well as the type strain <it>O. anthropi </it>ATCC49188^Tand 2 strains of <it>Ochrobactrum lupini </it>and <it>Ochrobactrum cytisi </it>isolated from plant nodules. A Multi-Locus Sequence Typing (MLST) scheme for <it>O. anthropi </it>is proposed here for the first time. It was based on 7 genes (3490 nucleotides) evolving mostly by neutral mutations. The MLST approach suggested an epidemic population structure. A major clonal complex corresponded to a human-associated lineage since it exclusively contained clinical isolates. Genomic fingerprinting separated isolates displaying the same sequence type but it did not detect a population structure that could be related to the origin of the strains. None of the molecular method allowed the definition of particular lineages associated to the host-bacteria relationship (carriage, colonisation or infection). Antibiotyping was the least discriminative method.</p> <p>Conclusion</p> <p>The results reveal a human-associated subpopulation in our collection of strains. The emergence of this clonal complex was probably not driven by the antibiotic selective pressure. Therefore, we hypothesise that the versatile species <it>O. anthropi </it>could be considered as a human-specialized opportunistic pathogen.</p

Comparative diffusion assay to assess efficacy of topical antimicrobial agents against Pseudomonas aeruginosa in burns care

<p>Abstract</p> <p>Background</p> <p>Severely burned patients may develop life-threatening nosocomial infections due to <it>Pseudomonas aeruginosa</it>, which can exhibit a high-level of resistance to antimicrobial drugs and has a propensity to cause nosocomial outbreaks. Antiseptic and topical antimicrobial compounds constitute major resources for burns care but in vitro testing of their activity is not performed in practice.</p> <p>Results</p> <p>In our burn unit, a <it>P. aeruginosa </it>clone multiresistant to antibiotics colonized or infected 26 patients over a 2-year period. This resident clone was characterized by PCR based on ERIC sequences. We investigated the susceptibility of the resident clone to silver sulphadiazine and to the main topical antimicrobial agents currently used in the burn unit. We proposed an optimized diffusion assay used for comparative analysis of <it>P. aeruginosa </it>strains. The resident clone displayed lower susceptibility to silver sulphadiazine and cerium silver sulphadiazine than strains unrelated to the resident clone in the unit or unrelated to the burn unit.</p> <p>Conclusions</p> <p>The diffusion assay developed herein detects differences in behaviour against antimicrobials between tested strains and a reference population. The method could be proposed for use in semi-routine practice of medical microbiology.</p

Acetobacter cibinongensis Bacteremia in Human

Acetobacter cibinongensis Bacteremia in Human To the Editor: The genus Acetobacter belongs to the group of acetic acid bacteria that oxidize alcohols or sugars incompletely, leading to the accumulation of acetic acid. Acetic acid bacteria are of great industrial interest because of their use to produce vinegar from spirits, wine, beer, and cider in temperate regions of Europe, the Americas, and Japan. Several species seem to be associated with tropical climates. In Southeast Asia, Acetobacter spp. have been found in fermented foods such as tea fungus beverage, palm vinegar, palm wine, nata de coco, and pickles (1). A. cibinongensis is mainly found in tropical fruits and fl owers (2). We describe a case of human infection with a member of the genus Acetobacter. The patient was an HIV-seronegative, 40-year-old man who for 1 year had been receiving chronic hemodialysis for end-stage renal failure. He had a history of intravenous drug use, and continued use was suspected. In February 2005, when admitted for a routine dialysis session, he had fever (38°C) and bronchitis and was receiving empiric treatment with amoxicillin (2 g/day). His respiratory status improved slightly, but fever persisted after 48 hours. On his right forearm, he had a large infl ammatory skin lesion that followed the course of an arteriovenous fi stula, suggestive of staphylococcal infection. Treatment was switched to pristinamycin (2 g/ day for 4 days). The patient's leukocyte count was within normal limits, but his C-reactive protein level was elevated (50 mg/L). Two blood samples were drawn, 1 through a subclavian catheter implanted in 2004 and the other through the arteriovenous fi stula. After 4 days, a gram-variable polymorphic rod, named nîmes373

Bon usage des antibiotiques dans la prise en charge des pyélonéphrites aiguës communautaires (évaluation des pratiques professionnelles au CHU de Nîmes)

MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF

Les nouvelles approches de la polykystose rénale autosomique dominante

MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF

Achromobacter xylosoxidans et mucoviscidose (épidémiologie, diversité, évolution génomique et génétique au cours de la colonisation chronique)

MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF