A Type III Secretion System Is Required for
            <i>Aeromonas hydrophila</i>
            AH-1 Pathogenesis

Yu, Hong; Rao, P. S. Srinivasa; Lee, H. C.; Vilches, Silvia; Merino, Susana; Tomás, Juan M.; Leung, Ka Yin

doi:10.1128/iai.72.3.1248-1256.2004

Cited by 111 publications

(100 citation statements)

References 44 publications

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Section: Resultsmentioning

confidence: 53%

“…TTSSs have been reported in many gram-negative animal and plant pathogens, including A. hydrophila (6,9,46). As reported previously (46), an ascV homologue is present in A. hydrophila PPD134/91. Furthermore, an ascU homologue, near one end of the TTSS in A. hydrophila AH-1, was also identified in A. hydrophila PPD134/91 by PCR (ascU-F, 5-TGGTGATCGCCATCGCCG A-3; ascU-R, 5-GACGGCGCTTGCTCTTGAT-3).…”

Section: Resultsmentioning

confidence: 53%

“…Pulse-field gel electrophoresis was carried out as previously described (46). ProMega-Markers Lambda Ladders (Promega) were used as the size markers.…”

Section: Methodsmentioning

confidence: 99%

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Identification and Characterization of Putative Virulence Genes and Gene Clusters in Aeromonas hydrophila PPD134/91

Zhang

Lau

et al. 2005

Appl Environ Microbiol

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Aeromonas hydrophila is a gram-negative opportunistic pathogen of animals and humans. The pathogenesis of A. hydrophila is multifactorial. Genomic subtraction and markers of genomic islands (GIs) were used to identify putative virulence genes in A. hydrophila PPD134/91. Two rounds of genomic subtraction led to the identification of 22 unique DNA fragments encoding 19 putative virulence factors and seven new open reading frames, which are commonly present in the eight virulence strains examined. In addition, four GIs were found, including O-antigen, capsule, phage-associated, and type III secretion system (TTSS) gene clusters. These putative virulence genes and gene clusters were positioned on a physical map of A. hydrophila PPD134/91 to determine their genetic organization in this bacterium. Further in vivo study of insertion and deletion mutants showed that the TTSS may be one of the important virulence factors in A. hydrophila pathogenesis. Furthermore, deletions of multiple virulence factors such as S-layer, serine protease, and metalloprotease also increased the 50% lethal dose to the same level as the TTSS mutation (about 1 log) in a blue gourami infection model. This observation sheds light on the multifactorial and concerted nature of pathogenicity in A. hydrophila. The large number of putative virulence genes identified in this study will form the basis for further investigation of this emerging pathogen and help to develop effective vaccines, diagnostics, and novel therapeutics.Aeromonas hydrophila is a ubiquitous gram-negative bacterium of aquatic environments, which has been implicated as a causative agent of motile aeromonad septicemia in a variety of aquatic animals (especially freshwater fish species) (2, 37). It causes gastrointestinal and extraintestinal infections in humans, including septicemia, wound infections, and gastroenteritis (16). A number of virulence factors have been identified in A. hydrophila, namely, pili and adhesins (29, 30), O-antigens and capsules (23,48,49), S-layers (10), exotoxins such as hemolysins and enterotoxin (7,14), and a repertoire of exoenzymes which digest cellular components such as proteases, amylases, and lipases (20, 28).The pathogenesis of A. hydrophila is multifactorial. Most studies to date have concentrated on the characterization of a few virulence factors in different animal models by using different strains (10, 34, 42), making it very difficult to evaluate the significance of each gene in the virulence of A. hydrophila. This study aims to identify more putative virulence determinants and characterize them in an integrated manner.Suppressive subtraction hybridization or genomic subtraction offers a genome-level approach to identifying the genetic differences between virulent and avirulent strains of bacteria (22,47). In this study, we used genomic subtraction to identify 22 unique DNA fragments encoding 19 putative virulence factors and seven new open reading frames (ORFs), which are frequently present in a group of virulent strains of A. hydrophila. In...

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 53%

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Identification and Characterization of Putative Virulence Genes and Gene Clusters in Aeromonas hydrophila PPD134/91

Zhang

Lau

et al. 2005

Appl Environ Microbiol

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“…In fish, two species of the genus Aeromonas (A. salmonicida and A. hydrophila) have been reported to have a functional type III secretion system involved in virulence (Burr et al, 2002;Yu et al, 2004). In A. salmonicida, a mutation in the ascV gene that encodes an inner membrane component of the type III secretion apparatus results in the lack of toxicity against RTG-2 rainbow trout gonad cells (Burr et al, 2002).…”

Section: Protein Secretion Systemsmentioning

confidence: 99%

“…In A. salmonicida, a mutation in the ascV gene that encodes an inner membrane component of the type III secretion apparatus results in the lack of toxicity against RTG-2 rainbow trout gonad cells (Burr et al, 2002). In A. hydrophila AH-1, insertional inactivation of two of the type III secretion system genes (aopB and aopD) led to decreased cytotoxicity in carp epithelial cells, increased phagocytosis and reduced virulence in blue gourami (Trichogaster trichopterus Pallas) (Yu et al, 2004). E. tarda also has a type III secretion system that is essential for pathogenesis formed by three genes eseD, eseB and eseC.…”

Section: Protein Secretion Systemsmentioning

confidence: 99%

An Overview of Virulence-Associated Factors of Gram-Negative Fish Pathogenic Bacteria

Méndez¹,

Reimundo²,

Pérez-Pascual³

et al. 2012

Health and Environment in Aquaculture

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In Vitro Antibacterial Efficacy of Cymbopogon flexuosus Essential Oil against Aeromonas hydrophila of Fish Origin and in Silico Molecular Docking of the Essential Oil Components against DNA Gyrase‐B and Their Drug‐Likeness

Chowdhury

Bera

Raut

et al. 2023

Chemistry & Biodiversity

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In aquaculture, diseases caused by the Aeromonads with high antibiotic resistance are among the most common and troublesome diseases. Application of herbs is emerging as a tool in controlling these diseases. Plant extracts besides disease control, favor various physiological activities in fish. In this study, essential oil of Cymbopogon flexuosus (Poaceae family) was studied in vitro for its antibacterial efficacy against two oxytetracycline (OTC) resistant and one sensitive strains of Aeromonas hydrophila. The oil was found rich (86.93 %) in oxygenated terpenoids containing 74.15 % of citral. The oil exhibited dose dependent growth inhibition of the bacteria. Mean MIC value of the oil against the sensitive strain was recorded as 2.0 mg mL À 1 whereas MBC value was recorded as 4.0 mg mL À 1 . The oil was found effective against the OTC resistant isolates with the MIC and MBC values ranging from 2.67 -3.33 and 4.0 -6.67 mg mL À 1 , respectively. In silico molecular docking of the essential oil components against DNA gyrase-B, a vital macromolecule in bacterial cell, was carried out to computationally asses the efficacy of the oil against the bacteria. Some of the components of the essential oil strongly bonded with the enzyme to inhibit its efficacy. Binding energy of some components of the oil was comparable to that of the conventional antibiotic, OTC. The identified phytochemicals exhibited favorable physicochemical and pharmacokinetic properties and satisfied the rule of five (Ro5).

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A Type III Secretion System Is Required for Aeromonas hydrophila AH-1 Pathogenesis

Cited by 111 publications

References 44 publications

Identification and Characterization of Putative Virulence Genes and Gene Clusters in Aeromonas hydrophila PPD134/91

Identification and Characterization of Putative Virulence Genes and Gene Clusters in Aeromonas hydrophila PPD134/91

An Overview of Virulence-Associated Factors of Gram-Negative Fish Pathogenic Bacteria

In Vitro Antibacterial Efficacy of Cymbopogon flexuosus Essential Oil against Aeromonas hydrophila of Fish Origin and in Silico Molecular Docking of the Essential Oil Components against DNA Gyrase‐B and Their Drug‐Likeness

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