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Journal of Applied Microbiology Sep 2013To identify bacterial pathogens of diseased NiIe tilapia Oreochromis niloticus and determine their virulence.
Identification and virulence of Aeromonas dhakensis, Pseudomonas mosselii and Microbacterium paraoxydans isolated from Nile tilapia, Oreochromis niloticus, cultivated in Mexico.
AIMS
To identify bacterial pathogens of diseased NiIe tilapia Oreochromis niloticus and determine their virulence.
METHODS AND RESULTS
Sixteen bacterial isolates were recovered from diseased Nile tilapias (O. niloticus) reared in floating cages in Adolfo Lopez Mateos (ALM), Sanalona and Dique IV dams in Sinaloa, Mexico, from February to May 2009. The bacterial isolates were identified by phenotypic and molecular (rep-PCR and 16S rRNA sequencing) methods and were mostly isolated from the kidneys and the brain of tilapias. Bacterial cells and extracellular products (ECPs) of strains were characterized and used in experimental infections with sole Solea vulgaris and Mozambican tilapia Oreochromis mossambicus. The fish challenged with Aeromonas dhakensis sp. nov. comb nov, Pseudomonas mosselii and Microbacterium paraoxydans (3·1 × 10(6) CFU g(-) 1) exhibited mortality between 40 and 100% starting at 6 h postinoculation. The ECPs displayed gelatinase, haemolytic and cytotoxic activity, causing the total destruction of the HeLa cell lines.
CONCLUSIONS
Aeromonas dhakensis and Ps. mosselii were virulent to O. mossambicus, whereas Mic. paraoxydans displayed virulence to S. vulgaris.
SIGNIFICANCE AND IMPACT OF THE STUDY
This the first time that Aeromonas dhakensis and Ps. mosselii are reported as pathogens to tilapia and Mic. paraoxydans was isolated from fish; then, these fish pathogens could be a threat to farmed Nile tilapia in Mexico.
Topics: Actinomycetales; Aeromonas; Animals; Cichlids; Fish Diseases; HeLa Cells; Humans; Mexico; Pseudomonas; RNA, Ribosomal, 16S; Virulence
PubMed: 23758410
DOI: 10.1111/jam.12280 -
BMC Microbiology May 2013The genus Pseudomonas includes a heterogeneous set of microorganisms that can be isolated from many different niches and nearly 100 different strains have been... (Comparative Study)
Comparative Study
BACKGROUND
The genus Pseudomonas includes a heterogeneous set of microorganisms that can be isolated from many different niches and nearly 100 different strains have been described. The best characterized bacterium is Pseudomonas aeruginosa which is the primary agent of opportunistic infection in humans, causing both acute and chronic infections. Other species like fluorescens, putida or mosselii have been sporadically isolated from hospitalized patients but their association with the pathology often remains unclear.
RESULTS
This study focuses on the cytotoxicity and inflammatory potential of two strains of Pseudomonas mosselii (ATCC BAA-99 and MFY161) that were recently isolated from clinical samples of hospitalized patients. The behavior of these bacteria was compared to that of the well-known opportunistic pathogen P. aeruginosa PAO1. We found that P. mosselii ATCC BAA-99 and MFY161 are cytotoxic towards Caco-2/TC7 cells, have low invasive capacity, induce secretion of human β-defensin 2 (HBD-2), alter the epithelial permeability of differentiated cells and damage the F-actin cytoskeleton.
CONCLUSIONS
These data bring new insights into P. mosselii virulence, since this bacterium has often been neglected due to its rare occurrence in hospital.
Topics: Actins; Bacterial Toxins; Cell Line; Cell Membrane Permeability; Endocytosis; Epithelial Cells; Hospitals; Humans; Pseudomonas; Pseudomonas Infections; Virulence; beta-Defensins
PubMed: 23718251
DOI: 10.1186/1471-2180-13-123 -
VIM-1-producing Pseudomonas mosselii isolates in Italy, predating known VIM-producing index strains.Antimicrobial Agents and Chemotherapy Apr 2012
Topics: Anti-Bacterial Agents; Humans; Italy; Microbial Sensitivity Tests; Polymerase Chain Reaction; Pseudomonas; Pseudomonas Infections; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; beta-Lactamases
PubMed: 22290983
DOI: 10.1128/AAC.06005-11 -
Applied and Environmental Microbiology Jun 2002A total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through...
A total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through siderotyping, i.e., by the isoelectrophoretic characterization of their main siderophores and pyoverdines and determination of the pyoverdine-mediated iron uptake specificity of the strains. As a general rule, strains within a well-circumscribed taxonomic group, namely the species Pseudomonas brassicacearum, Pseudomonas fuscovaginae, Pseudomonas jessenii, Pseudomonas mandelii, Pseudomonas monteilii, "Pseudomonas mosselii," "Pseudomonas palleronii," Pseudomonas rhodesiae, "Pseudomonas salomonii," Pseudomonas syringae, Pseudomonas thivervalensis, Pseudomonas tolaasii, and Pseudomonas veronii and the genomospecies FP1, FP2, and FP3 produced an identical pyoverdine which, in addition, was characteristic of the group, since it was structurally different from the pyoverdines produced by the other groups. In contrast, 28 strains belonging to the notoriously heterogeneous Pseudomonas fluorescens species were characterized by great heterogeneity at the pyoverdine level. The study of 23 partially characterized phenotypic clusters demonstrated that siderotyping is very useful in suggesting correlations between clusters and well-defined species and in detecting misclassified individual strains, as verified by DNA-DNA hybridization. The usefulness of siderotyping as a determinative tool was extended to the nonfluorescent species Pseudomonas corrugata, Pseudomonas frederiksbergensis, Pseudomonas graminis, and Pseudomonas plecoglossicida, which were seen to have an identical species-specific siderophore system and thus were easily differentiated from one another. Thus, the fast, accurate, and easy-to-perform siderotyping method compares favorably with the usual phenotypic and genomic methods presently necessary for accurate identification of pseudomonads at the species level.
Topics: Fluorescence; Iron; Isoelectric Focusing; Oligopeptides; Pigments, Biological; Pseudomonas fluorescens; Siderophores; Statistics as Topic
PubMed: 12039729
DOI: 10.1128/AEM.68.6.2745-2753.2002