ABSTRACT
Subcutaneous mycoses in freshwater fish are rare infections usually caused by oomycetes of the genus Saprolegnia and some filamentous fungi. To date, Fusarium infections in farmed fish have only been described in marine fish. Here, we report the presence of Fusarium oxysporum in subcutaneous lesions of Nile tilapia (Oreochromis niloticus). Histopathologic evaluation revealed granuloma formation with fungal structures, and the identity of the etiological agent was demonstrated by morphological and molecular analyses. Some of the animals died as a result of systemic coinfection with Aeromonas hydrophila.
ABSTRACT
This study characterises a chromosomal gene of Lactococcus garvieae encoding a pentapeptide repeat protein designated as LgaQnr. This gene has been implicated in reduced susceptibility to quinolones in this bacterium, which is of relevance to both veterinary and human medicine. All of the L. garvieae isolates analysed were positive for the lgaqnr gene. The expression of lgaqnr in Escherichia coli reduced the susceptibility to quinolones, producing an adverse effect. The reduced susceptibility to ciprofloxacin was 16-fold in E. coli ATCC 25922 and 32-fold in E. coli DH10B, compared to the control strains. The minimum inhibitory concentration of nalidixic acid was also increased 4 or 5-fold. The effect of the expression of lgaqnr in E. coli was investigated by electron microscopy and was observed to affect the structure of the cell and the inner membrane of the recombinant cells.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Escherichia coli/drug effects , Gene Expression , Lactococcus/genetics , Quinolones/pharmacology , Cell Membrane/ultrastructure , Ciprofloxacin/pharmacology , Escherichia coli/genetics , Escherichia coli/ultrastructure , Lactococcus/drug effects , Microbial Sensitivity Tests , Microscopy, Electron, Transmission , Nalidixic Acid/pharmacology , Recombinant Proteins/biosynthesis , Recombinant Proteins/geneticsABSTRACT
The present work describes the molecular characterization of five circular plasmids found in the human clinical strain Lactococcus garvieae 21881. The plasmids were designated pGL1-pGL5, with molecular sizes of 4,536 bp, 4,572 bp, 12,948 bp, 14,006 bp and 68,798 bp, respectively. Based on detailed sequence analysis, some of these plasmids appear to be mosaics composed of DNA obtained by modular exchange between different species of lactic acid bacteria. Based on sequence data and the derived presence of certain genes and proteins, the plasmid pGL2 appears to replicate via a rolling-circle mechanism, while the other four plasmids appear to belong to the group of lactococcal theta-type replicons. The plasmids pGL1, pGL2 and pGL5 encode putative proteins related with bacteriocin synthesis and bacteriocin secretion and immunity. The plasmid pGL5 harbors genes (txn, orf5 and orf25) encoding proteins that could be considered putative virulence factors. The gene txn encodes a protein with an enzymatic domain corresponding to the family actin-ADP-ribosyltransferases toxins, which are known to play a key role in pathogenesis of a variety of bacterial pathogens. The genes orf5 and orf25 encode two putative surface proteins containing the cell wall-sorting motif LPXTG, with mucin-binding and collagen-binding protein domains, respectively. These proteins could be involved in the adherence of L. garvieae to mucus from the intestine, facilitating further interaction with intestinal epithelial cells and to collagenous tissues such as the collagen-rich heart valves. To our knowledge, this is the first report on the characterization of plasmids in a human clinical strain of this pathogen.
Subject(s)
Lactococcus/genetics , Plasmids/genetics , Aged , Amino Acid Sequence , Base Sequence , Chromosome Mapping , DNA Replication/genetics , Drug Resistance, Bacterial/genetics , Electrophoresis, Agar Gel , Gene Transfer, Horizontal/genetics , Genes, Bacterial/genetics , Humans , Lactococcus/pathogenicity , Male , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA , Virulence Factors/metabolismABSTRACT
Lactococcus garvieae is the etiological agent of lactococcosis, one of the most important disease threats to the sustainability of the rainbow trout farming industry. Here, we present the draft genome sequence of Lactococcus garvieae strain 8831, isolated from diseased rainbow trout, which is composed of 2,087,276 bp with a G+C content of 38%.
Subject(s)
Disease Outbreaks/veterinary , Fish Diseases/microbiology , Genome, Bacterial , Gram-Positive Bacterial Infections/veterinary , Lactococcus/genetics , Oncorhynchus mykiss , Animals , Base Sequence , Fish Diseases/epidemiology , Gram-Positive Bacterial Infections/epidemiology , Gram-Positive Bacterial Infections/microbiology , Lactococcus/classification , Molecular Sequence Data , Spain/epidemiologyABSTRACT
Lactococcus garvieae is a Gram-positive bacterium considered an important opportunistic emerging human pathogen and also a well-recognized fish pathogen. Here, we present the draft genome sequence of Lactococcus garvieae strain 21881 (2,164,557 bp, with a G+C content of 37.9%), which represents the first report of a genome sequence on Lactococcus garvieae.
Subject(s)
Bacteremia/microbiology , Genome, Bacterial , Lactococcus/isolation & purification , Aged , Base Sequence , Humans , Lactococcus/genetics , Male , Molecular Sequence DataABSTRACT
This study evaluates the utilization of lactose (Lac) and the presence of the phospho-β-galactosidase (lacG) gene as markers for distinguishing between fish (Lac-/lacG-) and dairy isolates (Lac+/lacG+) of Lactococcus garvieae, using a panel of L. garvieae isolates from different sources. None of the fish isolates produced acid from lactose (Lac-), however Lac-/lacG- isolates were observed in pigs, cows, birds and humans. Most of the dairy isolates (77.8%) were Lac+/lacG+, but some dairy isolates did not produce acid from this sugar. Data in the present study show that the ability to metabolize lactose and the presence of the lacG gene are heterogeneously scattered among L. garvieae isolates of different sources. Therefore, the use of these criteria as markers to differentiate between L. garvieae isolates of dairy and fish origin should be considered with caution (AU)
No disponible
Subject(s)
Humans , Animals , Cattle , Dairy Products/microbiology , Fishes/microbiology , Lactococcus/genetics , Lactococcus/isolation & purification , Lactose/metabolism , beta-Galactosidase/genetics , Bacteremia/microbiology , Bacteriuria/microbiology , Fresh Water/microbiology , Wastewater/microbiology , Skin/microbiologyABSTRACT
This study evaluates the utilization of lactose (Lac) and the presence of the phospho-ß-galactosidase (lacG) gene as markers for distinguishing between fish (Lac-/lacG-) and dairy isolates (Lac+/lacG+) of Lactococcus garvieae, using a panel of L. garvieae isolates from different sources. None of the fish isolates produced acid from lactose (Lac-), however Lac-/lacG- isolates were observed in pigs, cows, birds and humans. Most of the dairy isolates (77.8%) were Lac+/lacG+, but some dairy isolates did not produce acid from this sugar. Data in the present study show that the ability to metabolize lactose and the presence of the lacG gene are heterogeneously scattered among L. garvieae isolates of different sources. Therefore, the use of these criteria as markers to differentiate between L. garvieae isolates of dairy and fish origin should be considered with caution.