Bacterial strategies for immune systems — Role of the type VI secretion system

Wang, Yurou; Zeng, Minmin; Lin, Xin; Olovo, Chinasa Valerie; Su, Zhaoliang; Zhang, Ying

doi:10.1016/j.intimp.2022.109550

Cited by 2 publications

(2 citation statements)

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“…The T6SS plays an important role in the bacteria’s evasion of the host immune system. This secretions system can translocate proteins and toxins into the cytosol of other cells ( Wang et al, 2023 ). There was no difference in the protein secretions systems used by the two bacterial species and the T2SS and T6SS were found in all genomes, suggesting that these secretion systems play and important part in the pathogenicity of both A. hydrophila and A. dhakensis in Vietnamese striped catfish production.…”

Section: Discussionmentioning

confidence: 99%

Comparative genomic analysis of Aeromonas dhakensis and Aeromonas hydrophila from diseased striped catfish fingerlings cultured in Vietnam

Erickson,

Khoi,

Hounmanou

et al. 2023

Front. Microbiol.

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IntroductionMotile Aeromonas septicemia (MAS) is a burden for striped catfish (Pangasius hypophthalmus) farmers in Vietnam. MAS can be caused by several species of Aeromonas but Aeromonas hydrophila is seen as the leading cause of MAS in aquaculture, but recent reports suggest that A. dhakensis is also causing MAS.MethodsHere we investigated the bacterial etiology of MAS and compared the genomic features of A. hydrophila and A. dhakensis. We collected 86 isolates from diseased striped catfish fingerlings over 5 years from eight provinces in Vietnam. Species identification was done using PCR, MALDI-TOF and whole genome sequence (WGS). The MICs of commonly used antimicrobials was established. Thirty presumed A. hydrophila isolates were sequenced for species confirmation and genomic comparison. A phylogenetic analysis was conducted using publicly available sequences and sequences from this study.ResultsA total of 25/30 isolates were A. dhakensis sequence type (ST) 656 and 5/30 isolates were A. hydrophila ST 251. Our isolates and all publicly available A. hydrophila isolates from Vietnam belonged to ST 251 and differed with <200 single nucleotide polymorphisms (SNP). Similarly, all A. dhakensis isolates from Vietnam belonged to ST 656 and differed with <100 SNPs. The tet(A) gene was found in 1/5 A. hydrophila and 19/25 A. dhakensis. All A. hydrophila had an MIC ≤2 mg/L while 19/25 A. dhakensis had MIC ≥8 mg/L for oxytetracycline. The floR gene was only found in A. dhakensis (14/25) which showed a MIC ≥8 mg/L for florfenicol. Key virulence genes, i.e., aerA/act, ahh1 and hlyA were present in all genomes, while ast was only present in A. dhakensis.DiscussionThis study confirms previous findings where A. dhakensis was the dominating pathogen causing MAS and that the importance of A. hydrophila has likely been overestimated. The differences in antimicrobial susceptibility between the two species could indicate a need for targeted antimicrobial treatment plans. The lipopolysaccharide regions and outer membrane proteins did not significantly differ in their immunogenic potentials, but it remains to be determined with in vivo experiments whether there is a difference in the efficacy of available vaccines against A. hydrophila and A. dhakensis.

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Section: Discussionmentioning

confidence: 99%

Comparative genomic analysis of Aeromonas dhakensis and Aeromonas hydrophila from diseased striped catfish fingerlings cultured in Vietnam

Erickson,

Khoi,

Hounmanou

et al. 2023

Front. Microbiol.

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show abstract

“…Avian pathogenic Escherichia coli ( APEC ) is a widely spread pathogen in poultry, with multiple serotypes that cause severe respiratory and systemic diseases, thus posing a major threat to the global poultry industry, food security, and bird survival ( Hu et al, 2022 ). The pathogenic mechanisms of APEC are complex and diverse ( Kathayat et al, 2021 ), among which the type VI secretion system ( T6SS ) is a special needle-like secretion system widely found in gram-negative bacteria, and T6SS is an important virulence factor of APEC, which promotes bacterial survival and proliferation by secreting a variety of effector proteins as a molecular weapon to attack the host cells ( Hood et al, 2010 ; Ma et al, 2014 , 2015 ; Wang et al, 2023 ). The hemolysin co-regulatory protein ( Hcp ) acts as a marker for the T6SS, both as a structural protein forming a transmembrane hexameric pore for the T6SS and as an effector protein ( Pukatzki et al, 2009 ).…”

Section: Introductionmentioning

confidence: 99%