Description of an original integron encompassing blaVIM-2, qnrVC1 and genes encoding bacterial group II intron proteins in Pseudomonas aeruginosa.

OBJECTIVES: A burn unit of a hospital in Tunis underwent an endemic situation caused by imipenem-resistant Pseudomonas aeruginosa. For nine non-repetitive isolates of a clonal VIM-2-producing strain, the blaVIM-2 genetic background was characterized and the associated qnrVC1 gene molecularly analysed. METHODS: The imipenem resistance mechanism was investigated by phenotypic and molecular tests, and resistance transfer was studied by conjugation and transformation experiments. The integron's structure was characterized by sequencing, and qnrVC1 expression was explored after cloning experiments. RESULTS: The nine VIM-2-producing strains were collected from eight patients and one environmental sample. All transfer assays failed, suggesting a chromosomal location of blaVIM-2. This latter was found to be part of a class 1 integron of ∼7500 bp, which also contains blaOXA-2, aadA1 and two copies of the aadB, arr-6 and qnrVC1 genes. qnrVC1 exhibited higher homology with the chromosomally encoded qnr genes of Vibrionaceae than with plasmid-mediated qnr genes of Enterobacteriaceae. The qnrVC1 gene cassette possesses a promoter allowing its expression, and it conferred decreased fluoroquinolone susceptibility to Escherichia coli. Additionally, on the same integron, genes encoding an uncommon group IIC-attC intron were detected. CONCLUSIONS: A VIM-2-producing P. aeruginosa outbreak led us to characterize an integron harbouring a qnrVC1 cassette and a new group IIC-attC intron. This is the first known description of a qnr determinant in a P. aeruginosa strain. Its presence conferred a low level of resistance to quinolones in E. coli, which might favour the emergence of highly resistant mutants.

Decision-making heterogeneity in obsessive-compulsive disorder: ventromedial prefrontal cortex function predicts different treatment outcomes.

Certain clinical aspects of patients with Obsessive-Compulsive Disorder (OCD) appear similar to those of patients with damage to the ventromedial sector of the prefrontal cortex. The hypothesis for the involvement of the frontal region in OCD is also supported by neuropsychological findings. Building on this evidence, we assessed the performance of a group of 34 OCD patients on a measure indexing with orbitofrontal cortex functioning and compared it with the performance of two other subject groups, one consisting of 34 healthy control subjects and the other 16 patients with panic disorder. All study subjects performed a neuropsychological task, which is sensitive to frontal lobe dysfunction and simulating real-life decision-making. Significant differences were found between the neuropsychological profiles of the OCD and of other groups, pointing to a possible specificity of decision-making deficit in OCD. Comparison of the performance of the OCD patients grouped according to response to antiobsessive drug treatment showed that poor neuropsychological task performance predicted poor outcome of pharmacological treatment. Task behavior did not correlate with severity of illness or demographic characteristics of the subjects. Results support the role of the ventromedial prefrontal cortex in OCD.