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Mahmood S, Rasool F, Hafeez-ur-Rehman M, Anjum KM. Molecular characterization of Aeromonas hydrophila detected in Channa marulius and Sperata sarwari sampled from rivers of Punjab in Pakistan. PLoS One 2024; 19:e0297979. [PMID: 38551906 PMCID: PMC10980204 DOI: 10.1371/journal.pone.0297979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/15/2024] [Indexed: 04/01/2024] Open
Abstract
Aeromonas hydrophila is one of the major pathogenic bacteria responsible for causing severe outbreaks at fish farms and is also a major global public health concern. This bacterium harbors many virulence genes. The current study was designed to evaluate the antidrug and virulence potential of A. hydrophila by amplifying its antimicrobial resistance and virulence genes using PCR and examining their effects on fish tissues and organs. A total of 960 fish samples of Channa marulius and Sperata sarwari were collected from four sites of the rivers of the Punjab, Pakistan. A. hydrophila isolates were subjected to biochemical identification and detection of virulence and antimicrobial resistance (AMR) genes by PCR. We retrieved 181 (6.46%) A. hydrophila isolates from C. marulius and 177 (6.25%) isolates from S. sarwari. Amplification through PCR revealed the incidence of virulence genes in 95.7% of isolates in C. marulius and 94.4% in S. sarwari. Similarly, amplification through PCR also revealed occurrence of AMR genes in 87.1% of isolates in C. marulius and 83.9% in S. sarwari. Histopathological examination revealed congestion (5.2%) and hepatocyte necrosis (4.6%) in liver, lamellar fusion (3.3%) and the presence of bacterial colonies (3.7%) in gills, fin erosion (6%), and the presence of biofilms (3.5%) in tail fins of infected fish. Phylogenetic tree analysis of 16S rRNA and gyrB gene of A. hydrophila revealed 100% and 97% similarity, respectively, with 16S rRNA gene and gyrB of A. hydrophila isolated in previous studies. The results of antimicrobial susceptibility testing showed that all isolates demonstrated resistance to sulfamethoxazole, ampicillin, neomycin, and norfloxacin, while susceptibility to gentamicin, chloramphenicol, and tetracycline, and intermediate resistance was observed against cefotaxime. The results concluded that examined fish samples were markedly contaminated with virulent and multidrug strains of A. hydrophila which may be of a potential health risk. The study emphasizes the responsible antimicrobial use in aquaculture and the urgent need for effective strategies to control the spread of virulence and antimicrobial resistance genes in A. hydrophila.
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Affiliation(s)
- Shahid Mahmood
- Department of Fisheries and Aquaculture, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Fayyaz Rasool
- Department of Zoology, Faisalabad Campus, University of Education, Lahore, Pakistan
| | - Muhammad Hafeez-ur-Rehman
- Department of Fisheries and Aquaculture, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Khalid Mahmood Anjum
- Department of Wildlife and Ecology, University of Veterinary and Animal Sciences, Lahore, Pakistan
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Liu M, Zhao MY, Wang H, Wang ZH, Wang Z, Liu Y, Li YP, Dong T, Fu Y. Pesticin-Like Effector VgrG3 cp Targeting Peptidoglycan Delivered by the Type VI Secretion System Contributes to Vibrio cholerae Interbacterial Competition. Microbiol Spectr 2023; 11:e0426722. [PMID: 36625646 PMCID: PMC9927483 DOI: 10.1128/spectrum.04267-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 12/13/2022] [Indexed: 01/11/2023] Open
Abstract
Vibrio cholerae can utilize a type VI secretion system (T6SS) to increase its intra- and interspecies competition. However, much still remains to be understood about the underlying mechanism of this intraspecies competition. In this study, we isolated an environmental V. cholerae strain E1 that lacked the typical virulence factors toxin-coregulated pilus and cholera toxin and that encoded a functional T6SS. We identified an evolved VgrG3 variant with a predicted C-terminal pesticin-like domain in V. cholerae E1, designated VgrG3cp. Using heterologous expression, protein secretion, and peptidoglycan-degrading assays, we demonstrated that VgrG3cp is a T6SS-dependent effector harboring cell wall muramidase activity and that its toxicity can be neutralized by cognate immunity protein TsiV3cp. Site-directed mutagenesis proved that the aspartic acid residue at position 867 is crucial for VgrG3cp-mediated antibacterial activity. Bioinformatic analysis showed that genes encoding VgrG3cp-like homologs are distributed in Vibrio species, are linked with T6SS structural genes and auxiliary genes, and the vgrG3cp-tsiV3cp gene pair of V. cholerae probably evolved from Vibrio anguillarum and Vibrio fluvialis via homologous recombination. Through a time-lapse microscopy assay, we directly determined that cells accumulating VgrG3cp disrupted bacterial division, while the cells continued to increase in size until the loss of membrane potential and cell wall breakage and finally burst. The results of the competitive killing assay showed that VgrG3cp contributes to V. cholerae interspecies competition. Collectively, our study revealed a novel T6SS E-I pair representing a new T6SS toxin family which allows V. cholerae to gain dominance within polymicrobial communities by T6SS. IMPORTANCE The type VI secretion system used by a broad range of Gram-negative bacteria delivers toxic proteins to target adjacent eukaryotic and prokaryotic cells. Diversification of effector proteins determines the complex bacterium-bacterium interactions and impacts the health of hosts and environmental ecosystems in which bacteria reside. This work uncovered an evolved valine-glycine repeat protein G3, carrying a C-terminal pesticin-like domain (VgrG3cp), which has been suggested to harbor cell wall hydrolase activity and is able to affect cell division and the integrity of cell wall structure. Pesticin-like homologs constitute a family of T6SS-associated effectors targeting bacterial peptidoglycan which are distributed in Vibrio species, and genetic loci of them are linked with T6SS structural genes and auxiliary genes. T6SS-delivered VgrG3cp mediated broad-spectrum antibacterial activity for several microorganisms tested, indicating that VgrG3cp-mediated antimicrobial activity is capable of conferring bacteria a competitive advantage over competitors in the same niches.
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Affiliation(s)
- Ming Liu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Meng-Yu Zhao
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
- The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, China
| | - Heng Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Zeng-Hang Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhao Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Ying Liu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yin-Peng Li
- The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, China
| | - Tao Dong
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yang Fu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
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Liang B, Ji X, Jiang B, Yuan T, Gerile CLM, Zhu L, Wang T, Li Y, Liu J, Guo X, Sun Y. Virulence, Antibiotic Resistance, and Phylogenetic Relationships of Aeromonas spp. Carried by Migratory Birds in China. Microorganisms 2022; 11:microorganisms11010007. [PMID: 36677299 PMCID: PMC9862355 DOI: 10.3390/microorganisms11010007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
This study aimed to evaluate antimicrobial resistance, virulence, and the genetic diversity of Aeromonas isolated from migratory birds from Guangxi Province, Guangdong Province, Ningxia Hui Autonomous Region, Jiangxi Province, and Inner Mongolia in China. A total of 810 samples were collected, including fresh feces, cloacal swabs, and throat swabs. The collected samples were processed and subjected to bacteriological examination. The resistance to 21 antibiotics was evaluated. A phylogenetic tree was constructed using concatenated gltA-groL-gyrB-metG-PPSA-recA sequences. Eight putative virulence factors were identified by PCR and sequencing, and a biofilm formation assay was performed using a modified microtiter plate method. In total, 176 Aeromonas isolates were isolated including A. sobria, A. hydrophila, A. veronii, and A. caviae. All isolates showed variable resistance against all 16 tested antibiotic discs, and only one antibiotic had no reference standard. Six kinds of virulence gene markers were discovered, and the detection rates were 46.0% (hlyA), 76.1% (aerA), 52.3% (alt), 4.5% (ast), 54.0% (fla), and 64.2% (lip). These strains were able to form biofilms with distinct magnitudes; 102 were weakly adherent, 14 were moderately adherent, 60 were non-adherent, and none were strongly adherent. Our results suggest that migratory birds carry highly virulent and multidrug-resistant Aeromonas and spread them around the world through migration, which is a potential threat to public health.
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Affiliation(s)
- Bing Liang
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
- Correspondence: (B.L.); (Y.S.)
| | - Xue Ji
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Bowen Jiang
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Tingyu Yuan
- Ruminant Diseases Research Center, College of Life Sciences, Shandong Normal University, Jinan 250013, China
| | - Chao Lu Men Gerile
- Center for Animal Disease Control and Prevention of Yi Jin Huo Luo Banner, Ordos 017299, China
| | - Lingwei Zhu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Tiecheng Wang
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Yuanguo Li
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Jun Liu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Xuejun Guo
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
| | - Yang Sun
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130117, China
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun 130117, China
- Ruminant Diseases Research Center, College of Life Sciences, Shandong Normal University, Jinan 250013, China
- Correspondence: (B.L.); (Y.S.)
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Dubey S, Ager-Wick E, Kumar J, Karunasagar I, Karunasagar I, Peng B, Evensen Ø, Sørum H, Munang’andu HM. Aeromonas species isolated from aquatic organisms, insects, chicken, and humans in India show similar antimicrobial resistance profiles. Front Microbiol 2022; 13:1008870. [PMID: 36532495 PMCID: PMC9752027 DOI: 10.3389/fmicb.2022.1008870] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/14/2022] [Indexed: 01/07/2024] Open
Abstract
Aeromonas species are Gram-negative bacteria that infect various living organisms and are ubiquitously found in different aquatic environments. In this study, we used whole genome sequencing (WGS) to identify and compare the antimicrobial resistance (AMR) genes, integrons, transposases and plasmids found in Aeromonas hydrophila, Aeromonas caviae and Aeromonas veronii isolated from Indian major carp (Catla catla), Indian carp (Labeo rohita), catfish (Clarias batrachus) and Nile tilapia (Oreochromis niloticus) sampled in India. To gain a wider comparison, we included 11 whole genome sequences of Aeromonas spp. from different host species in India deposited in the National Center for Biotechnology Information (NCBI). Our findings show that all 15 Aeromonas sequences examined had multiple AMR genes of which the Ambler classes B, C and D β-lactamase genes were the most dominant. The high similarity of AMR genes in the Aeromonas sequences obtained from different host species point to interspecies transmission of AMR genes. Our findings also show that all Aeromonas sequences examined encoded several multidrug efflux-pump proteins. As for genes linked to mobile genetic elements (MBE), only the class I integrase was detected from two fish isolates, while all transposases detected belonged to the insertion sequence (IS) family. Only seven of the 15 Aeromonas sequences examined had plasmids and none of the plasmids encoded AMR genes. In summary, our findings show that Aeromonas spp. isolated from different host species in India carry multiple AMR genes. Thus, we advocate that the control of AMR caused by Aeromonas spp. in India should be based on a One Health approach.
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Affiliation(s)
- Saurabh Dubey
- Section of Experimental Biomedicine, Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Eirill Ager-Wick
- Section of Experimental Biomedicine, Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Jitendra Kumar
- College of Fisheries, Acharya Narendra Deva University of Agriculture and Technology, Uttar Pradesh, India
| | - Indrani Karunasagar
- Nitte University Centre for Science Education and Research, Mangaluru, India
| | - Iddya Karunasagar
- Nitte University Centre for Science Education and Research, Mangaluru, India
| | - Bo Peng
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Pharmaceutical Functional Genes, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Higher Education Mega Center, Guangzhou, China
| | - Øystein Evensen
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Henning Sørum
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Hetron M. Munang’andu
- Section of Experimental Biomedicine, Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
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Conte D, Palmeiro J, Bavaroski A, Rodrigues L, Cardozo D, Tomaz A, Camargo J, Dalla‐Costa L. Antimicrobial resistance in
Aeromonas
species isolated from aquatic environments in Brazil. J Appl Microbiol 2021; 131:169-181. [DOI: https:/doi.org/10.1111/jam.14965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- D. Conte
- Faculdades Pequeno Príncipe (FPP) Curitiba, Paraná Brazil
- Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP) Curitiba, Paraná Brazil
| | - J.K. Palmeiro
- Faculdades Pequeno Príncipe (FPP) Curitiba, Paraná Brazil
- Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP) Curitiba, Paraná Brazil
- Departamento de Análises Clínicas Universidade Federal de Santa Catarina (ACL‐UFSC) Florianópolis, Santa Catarina Brazil
| | - A.A. Bavaroski
- Faculdades Pequeno Príncipe (FPP) Curitiba, Paraná Brazil
- Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP) Curitiba, Paraná Brazil
| | - L.S. Rodrigues
- Faculdades Pequeno Príncipe (FPP) Curitiba, Paraná Brazil
- Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP) Curitiba, Paraná Brazil
| | - D. Cardozo
- Liga Paranaese de Combate ao Câncer ‐ Hospital Erasto Gaertner (HEG) Curitiba, Paraná Brazil
| | - A.P. Tomaz
- Faculdades Pequeno Príncipe (FPP) Curitiba, Paraná Brazil
- Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP) Curitiba, Paraná Brazil
- Complexo Hospital de ClínicasUniversidade Federal do Paraná (CHC‐UFPR) Curitiba, Paraná Brazil
| | - J.O. Camargo
- Departamento de Bioquímica e Biologia Molecular Universidade Federal do Paraná (UFPR) Curitiba, Paraná Brazil
- Setor de Educação Profissional e Tecnológica (SEPT) Programa de Graduação em Bioinformática Universidade Federal do Paraná (UFPR) Curitiba, Paraná Brazil
| | - L.M. Dalla‐Costa
- Faculdades Pequeno Príncipe (FPP) Curitiba, Paraná Brazil
- Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP) Curitiba, Paraná Brazil
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Conte D, Palmeiro JK, Bavaroski AA, Rodrigues LS, Cardozo D, Tomaz AP, Camargo JO, Dalla-Costa LM. Antimicrobial resistance in Aeromonas species isolated from aquatic environments in Brazil. J Appl Microbiol 2020; 131:169-181. [PMID: 33306232 DOI: 10.1111/jam.14965] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/16/2020] [Accepted: 12/07/2020] [Indexed: 11/28/2022]
Abstract
AIM The current study was conducted to determine the antimicrobial resistance profile and genetic relatedness of Aeromonas sp. isolated from healthcare and urban effluents, wastewater treatment plant (WWTP) and river water. METHODS AND RESULTS We detected the presence of genes conferring resistance to β-lactam, quinolone and aminoglycoside. Multilocus sequence typing was carried out to differentiate the strains, and multilocus phylogenetic analysis was used to identify the species. A total of 28 cefotaxime-resistant Aeromonas sp. strains were identified, harbouring uncommon Guiana-extended-spectrum (GES)-type β-lactamases (GES-1, GES-5, GES-7 and GES-16). Multidrug-resistant Aeromonas sp. were found in hospital wastewater, WWTP and sanitary effluent, and A. caviae was identified as the most prevalent species (85·7%). CONCLUSION The release of untreated healthcare effluents, presence of antimicrobials in the environment, in addition to multidrug-resistant Aeromonas sp., are all potential factors for the spread of resistance. SIGNIFICANCE AND IMPACT OF THE STUDY We identified a vast repertoire of antimicrobial resistance genes (ARG) in Aeromonas sp. from diverse aquatic ecosystems, including those that encode enzymes degrading broad-spectrum antimicrobials widely used to treat healthcare-associated infections. Hospital and sanitary effluents serve as potential sources of bacteria harbouring ARG and are a threat to public health.
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Affiliation(s)
- D Conte
- Faculdades Pequeno Príncipe (FPP), Curitiba, Paraná, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP), Curitiba, Paraná, Brazil
| | - J K Palmeiro
- Faculdades Pequeno Príncipe (FPP), Curitiba, Paraná, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP), Curitiba, Paraná, Brazil.,Departamento de Análises Clínicas, Universidade Federal de Santa Catarina (ACL-UFSC), Florianópolis, Santa Catarina, Brazil
| | - A A Bavaroski
- Faculdades Pequeno Príncipe (FPP), Curitiba, Paraná, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP), Curitiba, Paraná, Brazil
| | - L S Rodrigues
- Faculdades Pequeno Príncipe (FPP), Curitiba, Paraná, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP), Curitiba, Paraná, Brazil
| | - D Cardozo
- Liga Paranaese de Combate ao Câncer - Hospital Erasto Gaertner (HEG), Curitiba, Paraná, Brazil
| | - A P Tomaz
- Faculdades Pequeno Príncipe (FPP), Curitiba, Paraná, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP), Curitiba, Paraná, Brazil.,Complexo Hospital de Clínicas, Universidade Federal do Paraná (CHC-UFPR), Curitiba, Paraná, Brazil
| | - J O Camargo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná (UFPR), Curitiba, Paraná, Brazil.,Setor de Educação Profissional e Tecnológica (SEPT), Programa de Graduação em Bioinformática, Universidade Federal do Paraná (UFPR), Curitiba, Paraná, Brazil
| | - L M Dalla-Costa
- Faculdades Pequeno Príncipe (FPP), Curitiba, Paraná, Brazil.,Instituto de Pesquisa Pelé Pequeno Príncipe (IPPPP), Curitiba, Paraná, Brazil
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Genetic relatedness and novel sequence types of clinical Aeromonas dhakensis from Malaysia. Braz J Microbiol 2020; 51:909-918. [PMID: 32067209 DOI: 10.1007/s42770-020-00239-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 02/03/2020] [Indexed: 12/18/2022] Open
Abstract
Aeromonas dhakensis is an emergent human pathogen with medical importance. This study was aimed to determine the sequence types (STs), genetic diversity, and phylogenetic relationships of different clinical sources of 47 A. dhakensis from Malaysia using multilocus sequence typing (MLST), goeBURST, and phylogenetic analyses. The analysis of a concatenated six-gene tree with a nucleotide length of 2994 bp based on six housekeeping genes (gyrB, groL, gltA, metG, ppsA, and recA) and independent analyses of single gene fragments was performed. MLST was able to group 47 A. dhakensis from our collection into 36 STs in which 34 STs are novel STs. The most abundant ST521 consisted of five strains from peritoneal fluid and two strains from stools. Comparison of 62 global A. dhakensis was carried out via goeBURST; 94.4% (34/36) of the identified STs are novel and unique in Malaysia. Two STs (111 and 541) were grouped into clonal complexes among our strains and 32 STs occurred as singletons. Single-gene phylogenetic trees showed varying topologies; groL and rpoD grouped all A. dhakensis into a tight-cluster with bootstrap values of 100% and 99%, respectively. A poor phylogenetic resolution encountered in single-gene analyses was buffered by the multilocus phylogenetic tree that offered high discriminatory power (bootstrap value = 100%) in resolving all A. dhakensis from A. hydrophila and delineating the relationship among other taxa. Genetic diversity analysis showed groL as the most conserved gene and ppsA as the most variable gene. This study revealed novel STs and high genetic diversity among clinical A. dhakensis from Malaysia.
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8
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Ma S, Dong Y, Wang N, Liu J, Lu C, Liu Y. Identification of a new effector-immunity pair of Aeromonas hydrophila type VI secretion system. Vet Res 2020; 51:71. [PMID: 32448355 PMCID: PMC7245790 DOI: 10.1186/s13567-020-00794-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 04/26/2020] [Indexed: 12/23/2022] Open
Abstract
The type VI secretion system (T6SS) is a multiprotein weapon that kills eukaryotic predators or prokaryotic competitors by delivering toxic effectors. Despite the importance of T6SS in bacterial environmental adaptation, it is still challenging to systematically identify T6SS effectors because of their high diversity and lack of conserved domains. In this report, we discovered a putative effector gene, U876-17730, in the whole genome of Aeromonas hydrophila NJ-35 based on the reported conservative domain DUF4123 (domain of unknown function), with two cognate immunity proteins encoded downstream. Phylogenetic tree analysis of amino acids indicates that AH17730 belongs to the Tle1 (type VI lipase effector) family, and therefore was named Tle1AH. The deletion of tle1AH resulted in significantly decreased biofilm formation, antibacterial competition ability and virulence in zebrafish (Danio rerio) when compared to the wild-type strain. Only when the two immunity proteins coexist can bacteria protect themselves from the toxicity of Tle1AH. Further study shows that Tle1AH is a kind of phospholipase that possesses a conserved lipase motif, Gly-X-Ser-X-Gly (X is for any amino acid). Tle1AH is secreted by T6SS, and this secretion requires its interaction with an associated VgrG (valine-glycine repeat protein G). In conclusion, we identified a T6SS effector-immunity pair and verified its function, which lays the foundation for future research on the role of T6SS in the pathogenic mechanism of A. hydrophila.
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Affiliation(s)
- Shuiyan Ma
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Nannan Wang
- College of Animal Science and Technology, Jinling Institute of Technology, Nanjing, 211169, China
| | - Jin Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
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9
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Diversity in gene arrangement in a DNA region lacking aerA in clinical and environmental Aeromonas hydrophila isolates. Antonie van Leeuwenhoek 2019; 113:71-81. [PMID: 31414275 DOI: 10.1007/s10482-019-01318-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/06/2019] [Indexed: 10/26/2022]
Abstract
Aquatic pathogen Aeromonas hydrophila produces an array of virulence factors, many of which are excreted proteins that causes infectious disease in fish, reptiles, and humans. Aerolysin, a haemolytic toxin, is the most well-known of the A. hydrophila virulence factors and is encoded by aerA. Although used as a virulence gene marker in several studies, recent whole-genome sequencing data suggest there may be some variation in aerolysin genes, as well as in the genetic environment of these genes, among A. hydrophila strains. Here, we used PCR-based assays to examine gene arrangement in the traditional aerA region of 42 aerA-minus clinical and environmental A. hydrophila isolates. PCR primers were designed based on known genes from within the target regions of reference strains carrying non-aerA aerolysin genes. Analyses revealed four different gene arrangement patterns among the isolates, indicating considerable genetic diversity in the target region. While 19 of the 21 environmental isolates showed the same gene pattern, all four patterns were represented among the clinical isolates, implying that the gene pattern is highly conserved in the target region among environmental isolates. Further analysis of the gene regions showed that the predominant pattern among environmental isolates, which did not contain an aerolysin gene, appeared to be the progenitor of the other three patterns, which likely arose as a result of gene acquisition, deletion, and rearrangement events during the evolution of A. hydrophila, and may be linked to the acquisition of aerolysin genes. These findings shed light on the evolution of virulence in A. hydrophila.
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