Characterization of the relationship between polar and lateral flagellar genes in clinical Aeromonas dhakensis: phenotypic, genetic and biochemical analyses

Lau, Tien-Tien Vicky; Puah, Suat Moi; Tan, Jin‐Ai Mary Anne; Puthucheary, S. D.; Chua, Kek Heng

doi:10.1007/s42770-021-00457-8

Cited by 3 publications

(3 citation statements)

References 39 publications

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“…OmpA is essential in the adhesion of the A. veronii strain onto the surface of the intestinal tract, and its adhesion activity was markedly reduced in a gene knockout mutant [28]. Moreover, in previous studies, flagellar-mediated motility-related genes (flgA, flgM, and flgN) have been demonstrated to be crucial virulence factors in many bacterial species [29]. Hemolytic toxin-related gene (hlyA) is widely present in Aeromonas species and is involved in the species' virulence [30].…”

Section: Discussionmentioning

confidence: 99%

Pathogenicity of Aeromonas veronii Isolated from Diseased Macrobrachium rosenbergii and Host Immune-Related Gene Expression Profiles

Gao,

Chen,

Zhang

et al. 2024

Microorganisms

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Aeromonas veronii is widespread in aquatic environments and is responsible for infecting various aquatic animals. In this study, a dominant strain was isolated from the hepatopancreas of diseased Macrobrachium rosenbergii and was named JDM1-1. According to its morphological, physiological, and biochemical characteristics and molecular identification, isolate JDM1-1 was identified as A. veronii. The results of artificial challenge showed isolate JDM1-1 had high pathogenicity to M. rosenbergii with an LD50 value of 8.35 × 105 CFU/mL during the challenge test. Histopathological analysis revealed severe damage in the hepatopancreas and gills of the diseased prawns, characterized by the enlargement of the hepatic tubule lumen and gaps between the tubules as well as clubbing and degeneration observed at the distal end of the gill filament. Eight virulence-related genes, namely aer, ompA, lip, tapA, hlyA, flgA, flgM, and flgN, were screened by PCR assay. In addition, virulence factor detection showed that the JDM1-1 isolate produced lipase, lecithinase, gelatinase, and hemolysin. Furthermore, the mRNA expression profiles of immune-related genes of M. rosenbergii following A. veronii infection, including ALF1, ALF2, Crustin, C-lectin, and Lysozyme, were assessed, and the results revealed a significant upregulation in the hepatopancreas and intestines at different hours post infection. This study demonstrates that A. veronii is a causative agent associated with massive die-offs of M. rosenbergii and contributes valuable insights into the pathogenesis and host defense mechanisms of A. veronii invasion.

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Section: Discussionmentioning

confidence: 99%

Pathogenicity of Aeromonas veronii Isolated from Diseased Macrobrachium rosenbergii and Host Immune-Related Gene Expression Profiles

Gao,

Chen,

Zhang

et al. 2024

Microorganisms

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“…The pellicle-forming and non-pellicle-forming isolates were selected and subjected to surface-associated motility assay following lab-established protocol ( Lau et al, 2021 ). Freshly prepared 25 mL nutrient broth containing 0.5% (w/v) Bacto™ agar (BD Difco, Franklin Lakes, NJ, USA) in 90 mm petri dishes and air-dried in laminar flow for 30 min were used as motility assay medium.…”

Section: Methodsmentioning

confidence: 99%

“…The plates were incubated at 37 °C for 24 h. Bacterial migration distance from the original inoculation site was measured. Motile Salmonella typhimurium ATCC 14028 and non-motile Klebsiella pneumoniae ATCC 700603 were used as positive and negative controls, respectively ( Kim & Surette, 2005 ; Lau et al, 2021 ). Three independent experiments were performed in triplicates and bacterial migration distance from the original inoculation site was measured.…”

Section: Methodsmentioning

confidence: 99%

Characterisation of pellicle-forming ability in clinical carbapenem-resistant Acinetobacter baumannii

Puah

Teh

et al. 2023

PeerJ

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Background Acinetobacter baumannii was reported to have resistance towards carbapenems and the ability to form an air-liquid biofilm (pellicle) which contributes to their virulence. The GacSA two-component system has been previously shown to play a role in pellicle formation. Therefore, this study aims to detect the presence of gacA and gacS genes in carbapenem-resistant Acinetobacter baumannii (CRAB) isolates recovered from patients in intensive care units and to investigate their pellicle forming ability. Methods The gacS and gacA genes were screened in 96 clinical CRAB isolates using PCR assay. Pellicle formation assay was performed in Mueller Hinton medium and Luria Bertani medium using borosilicate glass tubes and polypropylene plastic tubes. The biomass of the pellicle was quantitated using the crystal violet staining assay. The selected isolates were further assessed for their motility using semi-solid agar and monitored in real-time using real-time cell analyser (RTCA). Results All 96 clinical CRAB isolates carried the gacS and gacA genes, however, only four isolates (AB21, AB34, AB69 and AB97) displayed the ability of pellicle-formation phenotypically. These four pellicle-forming isolates produced robust pellicles in Mueller Hinton medium with better performance in borosilicate glass tubes in which biomass with OD570 ranging from 1.984 ± 0.383 to 2.272 ± 0.376 was recorded. The decrease in cell index starting from 13 hours obtained from the impedance-based RTCA showed that pellicle-forming isolates had entered the growth stage of pellicle development. Conclusion These four pellicle-forming clinical CRAB isolates could be potentially more virulent, therefore further investigation is warranted to provide insights into their pathogenic mechanisms.

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Flagellar motility mediates biofilm formation in Aeromonas dhakensis

Lau

Puah

Tan

et al. 2023

Microbial Pathogenesis

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Characterization of the relationship between polar and lateral flagellar genes in clinical Aeromonas dhakensis: phenotypic, genetic and biochemical analyses

Cited by 3 publications

References 39 publications

Pathogenicity of Aeromonas veronii Isolated from Diseased Macrobrachium rosenbergii and Host Immune-Related Gene Expression Profiles

Pathogenicity of Aeromonas veronii Isolated from Diseased Macrobrachium rosenbergii and Host Immune-Related Gene Expression Profiles

Characterisation of pellicle-forming ability in clinical carbapenem-resistant Acinetobacter baumannii

Flagellar motility mediates biofilm formation in Aeromonas dhakensis

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