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Morón Á, Tarhouchi AE, Belinchón I, Valenzuela JM, de Francisco P, Martín-González A, Amaro F. Protozoan predation enhances stress resistance and antibiotic tolerance in Burkholderia cenocepacia by triggering the SOS response. THE ISME JOURNAL 2024; 18:wrae014. [PMID: 38366016 PMCID: PMC10944698 DOI: 10.1093/ismejo/wrae014] [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: 09/04/2023] [Revised: 12/06/2023] [Accepted: 01/24/2024] [Indexed: 02/18/2024]
Abstract
Bacterivorous protists are thought to serve as training grounds for bacterial pathogens by subjecting them to the same hostile conditions that they will encounter in the human host. Bacteria that survive intracellular digestion exhibit enhanced virulence and stress resistance after successful passage through protozoa but the underlying mechanisms are unknown. Here we show that the opportunistic pathogen Burkholderia cenocepacia survives phagocytosis by ciliates found in domestic and hospital sink drains, and viable bacteria are expelled packaged in respirable membrane vesicles with enhanced resistance to oxidative stress, desiccation, and antibiotics, thereby contributing to pathogen dissemination in the environment. Reactive oxygen species generated within the protozoan phagosome promote the formation of persisters tolerant to ciprofloxacin by activating the bacterial SOS response. In addition, we show that genes encoding antioxidant enzymes are upregulated during passage through ciliates increasing bacterial resistance to oxidative radicals. We prove that suppression of the SOS response impairs bacterial intracellular survival and persister formation within protists. This study highlights the significance of protozoan food vacuoles as niches that foster bacterial adaptation in natural and built environments and suggests that persister switch within phagosomes may be a widespread phenomenon in bacteria surviving intracellular digestion.
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Affiliation(s)
- Álvaro Morón
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
| | - Alaa E Tarhouchi
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
| | - Iván Belinchón
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
| | - Juan M Valenzuela
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
| | - Patricia de Francisco
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
| | - Ana Martín-González
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
| | - Francisco Amaro
- Department of Genetics, Physiology and Microbiology. Faculty of Biological Sciences, Complutense University of MadridMadrid 28040, Spain
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Nguyen TBA, Bonkowski M, Dumack K, Chen QL, He JZ, Hu HW. Protistan predation selects for antibiotic resistance in soil bacterial communities. THE ISME JOURNAL 2023; 17:2182-2189. [PMID: 37794244 PMCID: PMC10689782 DOI: 10.1038/s41396-023-01524-8] [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: 05/08/2023] [Revised: 09/14/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023]
Abstract
Understanding how antibiotic resistance emerges and evolves in natural habitats is critical for predicting and mitigating antibiotic resistance in the context of global change. Bacteria have evolved antibiotic production as a strategy to fight competitors, predators and other stressors, but how predation pressure of their most important consumers (i.e., protists) affects soil antibiotic resistance genes (ARGs) profiles is still poorly understood. To address this gap, we investigated responses of soil resistome to varying levels of protistan predation by inoculating low, medium and high concentrations of indigenous soil protist suspensions in soil microcosms. We found that an increase in protistan predation pressure was strongly associated with higher abundance and diversity of soil ARGs. High protist concentrations significantly enhanced the abundances of ARGs encoding multidrug (oprJ and ttgB genes) and tetracycline (tetV) efflux pump by 608%, 724% and 3052%, respectively. Additionally, we observed an increase in the abundance of numerous bacterial genera under high protistan pressure. Our findings provide empirical evidence that protistan predation significantly promotes antibiotic resistance in soil bacterial communities and advances our understanding of the biological driving forces behind the evolution and development of environmental antibiotic resistance.
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Affiliation(s)
- Thi Bao-Anh Nguyen
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Michael Bonkowski
- Terrestrial Ecology, Institute of Zoology, University of Cologne, Köln, Germany
| | - Kenneth Dumack
- Terrestrial Ecology, Institute of Zoology, University of Cologne, Köln, Germany
| | - Qing-Lin Chen
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ji-Zheng He
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Hang-Wei Hu
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville, VIC, 3010, Australia.
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Lin C, Li LJ, Ren K, Zhou SYD, Isabwe A, Yang LY, Neilson R, Yang XR, Cytryn E, Zhu YG. Phagotrophic protists preserve antibiotic-resistant opportunistic human pathogens in the vegetable phyllosphere. ISME COMMUNICATIONS 2023; 3:94. [PMID: 37660098 PMCID: PMC10475086 DOI: 10.1038/s43705-023-00302-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/04/2023]
Abstract
Food safety of leafy greens is an emerging public health issue as they can harbor opportunistic human pathogens (OHPs) and expose OHPs to consumers. Protists are an integral part of phyllosphere microbial ecosystems. However, our understanding of protist-pathogen associations in the phyllosphere and their consequences on public health remains poor. Here, we examined phyllosphere protists, human pathogen marker genes (HPMGs), and protist endosymbionts from four species of leafy greens from major supermarkets in Xiamen, China. Our results showed that Staphylococcus aureus and Klebsiella pneumoniae were the dominant human pathogens in the vegetable phyllosphere. The distribution of HPMGs and protistan communities differed between vegetable species, of which Chinese chive possessed the most diverse protists and highest abundance of HPMGs. HPMGs abundance positively correlated with the diversity and relative abundance of phagotrophic protists. Whole genome sequencing further uncovered that most isolated phyllosphere protists harbored multiple OHPs which carried antibiotic resistance genes, virulence factors, and metal resistance genes and had the potential to HGT. Colpoda were identified as key phagotrophic protists which positively linked to OHPs and carried diverse resistance and virulence potential endosymbiont OHPs including Pseudomonas nitroreducens, Achromobacter xylosoxidans, and Stenotrophomonas maltophilia. We highlight that phyllosphere protists contribute to the transmission of resistant OHPs through internalization and thus pose risks to the food safety of leafy greens and human health. Our study provides insights into the protist-OHP interactions in the phyllosphere, which will help in food safety surveillance and human health.
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Affiliation(s)
- Chenshuo Lin
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, China
| | - Li-Juan Li
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, China
| | - Kexin Ren
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
| | - Shu-Yi-Dan Zhou
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou, 510650, China
| | - Alain Isabwe
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
| | - Le-Yang Yang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, China
| | - Roy Neilson
- Ecological Sciences, The James Hutton Institute, Dundee, DD2 5DA, Scotland, UK
| | - Xiao-Ru Yang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China
| | - Eddie Cytryn
- Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, The Volcani Institute, Agriculture Research Organization, 7528809, Rishon Lezion, Israel
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China.
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, China.
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Hoque MM, Espinoza-Vergara G, McDougald D. Protozoan predation as a driver of diversity and virulence in bacterial biofilms. FEMS Microbiol Rev 2023; 47:fuad040. [PMID: 37458768 DOI: 10.1093/femsre/fuad040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/19/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Protozoa are eukaryotic organisms that play a crucial role in nutrient cycling and maintaining balance in the food web. Predation, symbiosis and parasitism are three types of interactions between protozoa and bacteria. However, not all bacterial species are equally susceptible to protozoan predation as many are capable of defending against predation in numerous ways and may even establish either a symbiotic or parasitic life-style. Biofilm formation is one such mechanism by which bacteria can survive predation. Structural and chemical components of biofilms enhance resistance to predation compared to their planktonic counterparts. Predation on biofilms gives rise to phenotypic and genetic heterogeneity in prey that leads to trade-offs in virulence in other eukaryotes. Recent advances, using molecular and genomics techniques, allow us to generate new information about the interactions of protozoa and biofilms of prey bacteria. This review presents the current state of the field on impacts of protozoan predation on biofilms. We provide an overview of newly gathered insights into (i) molecular mechanisms of predation resistance in biofilms, (ii) phenotypic and genetic diversification of prey bacteria, and (iii) evolution of virulence as a consequence of protozoan predation on biofilms.
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Affiliation(s)
- M Mozammel Hoque
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Gustavo Espinoza-Vergara
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Diane McDougald
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Sydney, NSW 2007, Australia
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Zhu S, Yang B, Wang Z, Liu Y. Augmented dissemination of antibiotic resistance elicited by non-antibiotic factors. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115124. [PMID: 37327521 DOI: 10.1016/j.ecoenv.2023.115124] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/24/2023] [Accepted: 06/07/2023] [Indexed: 06/18/2023]
Abstract
The emergence and rapid spread of antibiotic resistance seriously compromise the clinical efficacy of current antibiotic therapies, representing a serious public health threat worldwide. Generally, drug-susceptible bacteria can acquire antibiotic resistance through genetic mutation or gene transfer, among which horizontal gene transfer (HGT) plays a dominant role. It is widely acknowledged that the sub-inhibitory concentrations of antibiotics are the key drivers in promoting the transmission of antibiotic resistance. However, accumulating evidence in recent years has shown that in addition to antibiotics, non-antibiotics can also accelerate the horizontal transfer of antibiotic resistance genes (ARGs). Nevertheless, the roles and potential mechanisms of non-antibiotic factors in the transmission of ARGs remain largely underestimated. In this review, we depict the four pathways of HGT and their differences, including conjugation, transformation, transduction and vesiduction. We summarize non-antibiotic factors accounting for the enhanced horizontal transfer of ARGs and their underlying molecular mechanisms. Finally, we discuss the limitations and implications of current studies.
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Affiliation(s)
- Shuyao Zhu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Bingqing Yang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Zhiqiang Wang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China.
| | - Yuan Liu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China; Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu, China.
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Rayamajhee B, Willcox MDP, Henriquez FL, Petsoglou C, Subedi D, Carnt N. Acanthamoeba, an environmental phagocyte enhancing survival and transmission of human pathogens. Trends Parasitol 2022; 38:975-990. [PMID: 36109313 DOI: 10.1016/j.pt.2022.08.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 01/13/2023]
Abstract
The opportunistic protist Acanthamoeba, which interacts with other microbes such as bacteria, fungi, and viruses, shows significant similarity in cellular and functional aspects to human macrophages. Intracellular survival of microbes in this microbivorous amoebal host may be a crucial step for initiation of infection in higher eukaryotic cells. Therefore, Acanthamoeba-microbe adaptations are considered an evolutionary model of macrophage-pathogen interactions. This paper reviews Acanthamoeba as an emerging human pathogen and different ecological interactions between Acanthamoeba and microbes that may serve as environmental training grounds and a genetic melting pot for the evolution, persistence, and transmission of potential human pathogens.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia.
| | - Mark D P Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia.
| | - Fiona L Henriquez
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland, Blantyre, South Lanarkshire, G72 0LH, UK
| | - Constantinos Petsoglou
- Sydney and Sydney Eye Hospital, Southeastern Sydney Local Health District, Sydney, Australia; Save Sight Institute, University of Sydney, Sydney, Australia
| | - Dinesh Subedi
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales (UNSW), Sydney, Australia
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Heterogeneous Growth Enhancement of Vibrio cholerae in the Presence of Different Phytoplankton Species. Appl Environ Microbiol 2022; 88:e0115822. [PMID: 36000870 PMCID: PMC9469713 DOI: 10.1128/aem.01158-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio cholerae is a ubiquitously distributed human pathogen that naturally inhabits marine and estuarine ecosystems. Two serogroups are responsible for causing cholera epidemics, O1 and O139, but several non-O1 and non-O139 V. cholerae (NOVC) strains can induce cholera-like infections. Outbreaks of V. cholerae have previously been correlated with phytoplankton blooms; however, links to specific phytoplankton species have not been resolved. Here, the growth of a NOVC strain (S24) was measured in the presence of different phytoplankton species, alongside phytoplankton abundance and concentrations of dissolved organic carbon (DOC). During 14-day experiments, V. cholerae S24 was cocultured with strains of the axenic phytoplankton species Actinocyclus curvatulus, Cylindrotheca closterium, a Pseudoscourfieldia sp., and a Picochlorum sp. V. cholerae abundances significantly increased in the presence of A. curvatulus, C. closterium, and the Pseudoscourfieldia sp., whereas abundances significantly decreased in the Picochlorum sp. coculture. V. cholerae growth was significantly enhanced throughout the cogrowth experiment with A. curvatulus, whereas when grown with C. closterium and the Pseudoscourfieldia sp., growth only occurred during the late stationary phase of the phytoplankton growth cycle, potentially coinciding with a release of DOC from senescent phytoplankton cells. In each of these cases, significant correlations between phytoplankton-derived DOC and V. cholerae cell abundances occurred. Notably, the presence of V. cholerae also promoted the growth of A. curvatulus and Picochlorum spp., highlighting potential ecological interactions. Variations in abundances of NOVC identified here highlight the potential diversity in V. cholerae-phytoplankton ecological interactions, which may inform efforts to predict outbreaks of NOVC in coastal environments. IMPORTANCE Many environmental strains of V. cholerae do not cause cholera epidemics but remain a public health concern due to their roles in milder gastrointestinal illnesses. With emerging evidence that these infections are increasing due to climate change, determining the ecological drivers that enable outbreaks of V. cholerae in coastal environments is becoming critical. Links have been established between V. cholerae abundance and chlorophyll a levels, but the ecological relationships between V. cholerae and specific phytoplankton species are unclear. Our research demonstrated that an environmental strain of V. cholerae (serogroup 24) displays highly heterogenous interactions in the presence of different phytoplankton species with a relationship to the dissolved organic carbon released by the phytoplankton species. This research points toward the complexity of the interactions of environmental strains of V. cholerae with phytoplankton communities, which we argue should be considered in predicting outbreaks of this pathogen.
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