DNA Delivery and Genomic Integration into Mammalian Target Cells through Type IV A and B Secretion Systems of Human Pathogens.

We explore the potential of bacterial secretion systems as tools for genomic modification of human cells. We previously showed that foreign DNA can be introduced into human cells through the Type IV A secretion system of the human pathogen . Moreover, the DNA is delivered covalently attached to the conjugative relaxase TrwC, which promotes its integration into the recipient genome.

A translocation motif in relaxase TrwC specifically affects recruitment by its conjugative type IV secretion system.

Type IV secretion system (T4SS) substrates are recruited through a translocation signal that is poorly defined for conjugative relaxases. The relaxase TrwC of plasmid R388 is translocated by its cognate conjugative T4SS, and it can also be translocated by the VirB/D4 T4SS of Bartonella henselae, causing DNA transfer to human cells. In this work, we constructed a series of TrwC variants and assayed them for DNA transfer to bacteria and human cells to compare recruitment requirements by both T4SSs.

Transfer of R388 derivatives by a pathogenesis-associated type IV secretion system into both bacteria and human cells.

Bacterial type IV secretion systems (T4SSs) are involved in processes such as bacterial conjugation and protein translocation to animal cells. In this work, we have switched the substrates of T4SSs involved in pathogenicity for DNA transfer. Plasmids containing part of the conjugative machinery of plasmid R388 were transferred by the T4SS of human facultative intracellular pathogen Bartonella henselae to both recipient bacteria and human vascular endothelial cells.

Comparison of phenotypical and genetic identification of Aeromonas strains isolated from diseased fish.

Phenotypicaly identified Aeromonas strains (n=119) recovered mainly from diseased fish were genetically re-identified and the concordance between the results was analysed. Molecular characterization based on the GCAT genus specific gene showed that only 90 (75.6%) strains belonged to the genus Aeromonas.

Aeromonas taiwanensis sp. nov. and Aeromonas sanarellii sp. nov., clinical species from Taiwan.

Two clinical Aeromonas strains (A2-50(T) and A2-67(T)) recovered from the wounds of two patients in Taiwan could not be assigned to any known species of this genus based on their 16S rRNA gene sequences, which showed similarities of 99.6-99.8 % to those of the type strains of Aeromonas caviae, A.

Clinical relevance of the recently described species Aeromonas aquariorum.

Twenty-two human extraintestinal isolates (11 from blood) and three isolates recovered from patients with diarrhea were genetically characterized as Aeromonas aquariorum, a novel species known only from ornamental fish. The isolates proved to bear a considerable number of virulence genes, and all were resistant to amoxicillin (amoxicilline), cephalothin (cefalotin), and cefoxitin. Biochemical differentiation from the most relevant clinical species is provided.

Aeromonas fluvialis sp. nov., isolated from a Spanish river.

A Gram-stain-negative, facultatively anaerobic bacterial strain, designated 717(T), was isolated from a water sample collected from the Muga river, Girona, north-east Spain. Preliminary analysis of the 16S rRNA gene sequence showed that this strain belonged to the genus Aeromonas, the nearest species being Aeromonas veronii (99.5 % similarity, with seven different nucleotides).

Development of imipenem resistance in an Aeromonas veronii biovar sobria clinical isolate recovered from a patient with cholangitis.

Several imipenem-susceptible and -resistant Aeromonas veronii biovar sobria isolates with different morphologies and antimicrobial susceptibilities recovered from bile samples of a patient with cholangitis were analysed. These isolates belonged to the same clone and the imipenem-resistant strains showed overexpression of the imiS gene, encoding a chromosomal carbapenemase. These results should make clinicians aware of the possible emergence of multidrug-resistant A.

Surgical site infection due to Aeromonas species: report of nine cases and literature review.

Gastrointestinal and wound infections are the most common clinical presentation of Aeromonas. Surgical site infections (SSIs) due to this microorganism are rare. We studied the clinical and microbiological characteristics of 9 cases that appeared at 2 Spanish hospitals and reviewed 15 cases available in the literature.

Analysis of 16S rRNA gene mutations in a subset of Aeromonas strains and their impact in species delineation.

Characterization of 999 Aeromonas strains using a published 16S rDNA RFLP identification method showed that 8.1% of the strains produced unexpected (hereafter called "atypical") restriction patterns, making their identification uncertain. Atypical patterns were due to the presence of nucleotide polymorphisms among the rrn operons of the 16S rRNA gene (so-called microheterogeneities).

Phylogenetic evidence suggests that strains of Aeromonas hydrophila subsp. dhakensis belong to the species Aeromonas aquariorum sp. nov.

Three strains of Aeromonas hydrophila subspecies dhakensis, including the type strain, were subjected to phylogenetic analysis by sequencing gyrB, rpoD, and 16S rRNA genes and compared with all known Aeromonas species. The obtained gyrB and rpoD phylogenetic trees clearly suggested that these A. hydrophila subsp.

Aeromonas hemolytic uremic syndrome. A case and a review of the literature.

Although rarely, hemolytic uremic syndrome can be induced by Aeromonas. We report a case in a 40-year-old Spanish female produced by Aeromonas veronii bv. sobria and review the previous cases described in the literature.