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Halpern M. Chironomid association with Vibrio cholerae. Microbiol Spectr 2024; 12:e0256723. [PMID: 38059589 PMCID: PMC10783102 DOI: 10.1128/spectrum.02567-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 07/18/2023] [Indexed: 12/08/2023] Open
Affiliation(s)
- Malka Halpern
- Department of Biology and Environment, University of Haifa at Oranim, Tivon, Israel
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel
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Ofek T, Trabelcy B, Izhaki I, Halpern M. Vibrio cholerae O1 Inhabit Intestines and Spleens of Fish in Aquaculture Ponds. MICROBIAL ECOLOGY 2023; 87:20. [PMID: 38148362 DOI: 10.1007/s00248-023-02330-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 12/05/2023] [Indexed: 12/28/2023]
Abstract
Vibrio cholerae is the causative agent of cholera, an acute diarrheal disease that spreads locally and globally in epidemics and pandemics. Although it was discovered that fish harbor V. cholerae strains in their intestines, most investigations revealed non-toxic V. cholerae serogroups in fish. Due to the rarity of toxigenic V. cholerae serogroups, it is difficult to cultivate these strains from environmental samples. Hence, here we aimed to uncover evidence of the occurrence of toxigenic V. cholerae in the intestines and spleens of various fish species. By using molecular detection tools, we show that V. cholerae O1 and strains positive for the cholera toxin inhabit both healthy and diseased fish intestines and spleens, suggesting that fish may serve as intermediate vectors of toxigenic V. cholerae. No significant differences were found between the abundance of toxigenic V. cholerae (either O1 or cholera toxin positive strains) in the healthy and the diseased fish intestines or spleens. In conclusion, a variety of fish species may serve as potential vectors and reservoirs of toxigenic V. cholerae as they form a link between the other reservoirs of V. cholerae (chironomids, copepods, and waterbirds). Similarly, they may aid in the spread of this bacterium between water bodies.
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Affiliation(s)
- Tamir Ofek
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
- Central Fish Health Laboratory, Fishery and Aquaculture Department, Ministry of Agriculture and Rural Development, Nir David, 1080300, Israel
| | - Beny Trabelcy
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
| | - Ido Izhaki
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel
| | - Malka Halpern
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, 3498838, Israel.
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Tivon, 3600600, Israel.
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Zhao D, Ali A, Zuck C, Uy L, Morris JG, Wong ACN. Vibrio cholerae Invasion Dynamics of the Chironomid Host Are Strongly Influenced by Aquatic Cell Density and Can Vary by Strain. Microbiol Spectr 2023; 11:e0265222. [PMID: 37074192 PMCID: PMC10269514 DOI: 10.1128/spectrum.02652-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 03/24/2023] [Indexed: 04/20/2023] Open
Abstract
Cholera has been a human scourge since the early 1800s and remains a global public health challenge, caused by the toxigenic strains of the bacterium Vibrio cholerae. In its aquatic reservoirs, V. cholerae has been shown to live in association with various arthropod hosts, including the chironomids, a diverse insect family commonly found in wet and semiwet habitats. The association between V. cholerae and chironomids may shield the bacterium from environmental stressors and amplify its dissemination. However, the interaction dynamics between V. cholerae and chironomids remain largely unknown. In this study, we developed freshwater microcosms with chironomid larvae to test the effects of cell density and strain on V. cholerae-chironomid interactions. Our results show that chironomid larvae can be exposed to V. cholerae up to a high inoculation dose (109 cells/mL) without observable detrimental effects. Meanwhile, interstrain variability in host invasion, including prevalence, bacterial load, and effects on host survival, was highly cell density-dependent. Microbiome analysis of the chironomid samples by 16S rRNA gene amplicon sequencing revealed a general effect of V. cholerae exposure on microbiome species evenness. Taken together, our results provide novel insights into V. cholerae invasion dynamics of the chironomid larvae with respect to various doses and strains. The findings suggest that aquatic cell density is a crucial driver of V. cholerae invasion success in chironomid larvae and pave the way for future work examining the effects of a broader dose range and environmental variables (e.g., temperature) on V. cholerae-chironomid interactions. IMPORTANCE Vibrio cholerae is the causative agent of cholera, a significant diarrheal disease affecting millions of people worldwide. Increasing evidence suggests that the environmental facets of the V. cholerae life cycle involve symbiotic associations with aquatic arthropods, which may facilitate its environmental persistence and dissemination. However, the dynamics of interactions between V. cholerae and aquatic arthropods remain unexplored. This study capitalized on using freshwater microcosms with chironomid larvae to investigate the effects of bacterial cell density and strain on V. cholerae-chironomid interactions. Our results suggest that aquatic cell density is the primary determinant of V. cholerae invasion success in chironomid larvae, while interstrain variability in invasion outcomes can be observed under specific cell density conditions. We also determined that V. cholerae exposure generally reduces species evenness of the chironomid-associated microbiome. Collectively, these findings provide novel insights into V. cholerae-arthropod interactions using a newly developed experimental host system.
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Affiliation(s)
- Dianshu Zhao
- Entomology and Nematology Department, University of Florida, Gainesville, Florida, USA
| | - Afsar Ali
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
| | - Cameron Zuck
- Entomology and Nematology Department, University of Florida, Gainesville, Florida, USA
| | - Laurice Uy
- Entomology and Nematology Department, University of Florida, Gainesville, Florida, USA
| | - J. Glenn Morris
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| | - Adam Chun-Nin Wong
- Entomology and Nematology Department, University of Florida, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
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Environmental Reservoirs of Pathogenic Vibrio spp. and Their Role in Disease: The List Keeps Expanding. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:99-126. [PMID: 36792873 DOI: 10.1007/978-3-031-22997-8_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Vibrio species are natural inhabitants of aquatic environments and have complex interactions with the environment that drive the evolution of traits contributing to their survival. These traits may also contribute to their ability to invade or colonize animal and human hosts. In this review, we attempt to summarize the relationships of Vibrio spp. with other organisms in the aquatic environment and discuss how these interactions could potentially impact colonization of animal and human hosts.
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Sela R, Halpern M. The Chironomid Microbiome Plays a Role in Protecting Its Host From Toxicants. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.796830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Organisms are assemblages of the host and their endogenous bacteria, which are defined as microbiomes. The host and its microbiome undergo a mutual evolutionary process to adapt to changes in the environment. Chironomids (Diptera; Chironomidae), are aquatic insects that grow and survive in polluted environments; however, the mechanisms that protect them under these conditions are not fully understood. Here we present evidence that the chironomids’ microbiome enables them to survival in polluted environments. It has been demonstrated that about 40% of the microbiota that inhabit Chironomus transvaalensis egg masses and larvae has the potential to detoxify different toxicants. Metagenomic analysis of Chironomus ramosus larvae demonstrated the presence of genes in the insects’ microbiome that can help the insects to survive in hostile environments. A set of experiments demonstrated that short exposure of C. transvaalensis larvae to metals significantly changed their microbiota composition in comparison to unexposed larvae. Another experiment, that followed Koch’s postulates, demonstrated that disinfected C. transvaalensis larvae can survive toxic lead and chromium exposure when they are recolonized with bacteria that can detoxify these toxic metals. This accumulating research, points to the conclusion that the chironomid microbiome plays a role in protecting its host from toxicants.
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Laviad-Shitrit S, Sela R, Sharaby Y, Thorat L, Nath BB, Halpern M. Comparative Microbiota Composition Across Developmental Stages of Natural and Laboratory-Reared Chironomus circumdatus Populations From India. Front Microbiol 2021; 12:746830. [PMID: 34899634 PMCID: PMC8661057 DOI: 10.3389/fmicb.2021.746830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/26/2021] [Indexed: 01/04/2023] Open
Abstract
Chironomids are aquatic insects that undergo a complete metamorphosis of four life stages. Here we studied, for the first time, the microbiota composition of Chironomus circumdatus, a tropical midge species, both from the Mula and Mutha Rivers in Pune, India and as a laboratory-reared culture. We generated a comparative microbial profile of the eggs, larvae and pupae, the three aquatic life stages of C. circumdatus. Non-metric multidimensional scaling analysis (NMDS) demonstrated that the developmental stage had a more prominent effect on the microbiota composition compared to the sampling location. Notably, the microbiota composition of the egg masses from the different sampling points clustered together and differed from laboratory culture larvae. Proteobacteria was the dominant phylum in all the environmental and laboratory-reared egg masses and pupal samples, and in the laboratory-reared larvae, while Fusobacteria was the dominant phylum in the larvae collected from the field environment. The most abundant genera were Cetobacterium, Aeromonas, Dysgonomonas, Vibrio, and Flavobacterium. The ten amplicon sequence variants (ASVs) that most significantly contributed to differences in microbiota composition between the three sampled locations were: Burkholderiaceae (ASVs 04 and 37), C39 (Rhodocyclaceae, ASV 14), Vibrio (ASV 07), Arcobacter (ASV 21), Sphaerotilus (ASV 22), Bacteroidia (ASVs 12 and 28), Flavobacterium (ASV 29), and Gottschalkia (ASV 10). No significant differences were found in the microbial richness (Chao1) or diversity (Shannon H’) of the three sampled locations. In contrast, significant differences were found between the microbial richness of the three life stages. Studying the microbiota of this Chironomus species may contribute to a better understanding of the association of C. circumdatus and its microbial inhabitants.
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Affiliation(s)
- Sivan Laviad-Shitrit
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel
| | - Rotem Sela
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel
| | - Yehonatan Sharaby
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel
| | - Leena Thorat
- Department of Zoology, Savitribai Phule Pune University, Pune, India.,Department of Biology, York University, Toronto, ON, Canada
| | - Bimalendu B Nath
- Department of Zoology, Savitribai Phule Pune University, Pune, India
| | - Malka Halpern
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel.,Department of Biology and Environment, University of Haifa, Haifa, Israel
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Chironomus ramosus Larval Microbiome Composition Provides Evidence for the Presence of Detoxifying Enzymes. Microorganisms 2021; 9:microorganisms9081571. [PMID: 34442650 PMCID: PMC8398091 DOI: 10.3390/microorganisms9081571] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 12/15/2022] Open
Abstract
Chironomids (Diptera; Chironomidae) are aquatic insects that are abundant in freshwater. We aimed to study the endogenous microbiota composition of Chironomus ramosus larvae that were sampled from the Mutha River and a laboratory culture in India. Furthermore, we performed a metagenomic analysis of the larval microbiome, sampled from the Mutha River. Significant differences were found between the bacterial community composition of C. ramosus larvae that were sampled from the Mutha River and the laboratory culture. A total of 54.7% of the amplicon sequence variants (ASVs) that were identified in the larvae from the Mutha River were unique, compared to only 12.9% of unique ASVs that were identified from the laboratory-reared larvae. The four most abundant phyla across all samples were: Proteobacteria, Fusobacteria, Firmicutes, and Bacteroidetes, while the nine most abundant genera were: Aeromonas, Alkanindiges, Breznakia, Cetobacterium, Chryseobacterium, Desulfovibrio, Dysgonomonas, Thiothrix, and Vibrio. Moreover, in the metagenomic analysis, we detected bacterial genes and bacterial pathways that demonstrated the ability to degrade different toxic compounds, detoxify metal, and confer resistance to antibiotics and UV radiation, amongst other functions. The results illuminate the fact that there are detoxifying enzymes in the C. ramosus larval microbiome that possibly play a role in protecting the insect in polluted environments.
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