1
|
Rayamajhee B, Williams NLR, Siboni N, Rodgers K, Willcox M, Henriquez FL, Seymour JR, Potts J, Johnson C, Scanes P, Carnt N. Identification and quantification of Acanthamoeba spp. within seawater at four coastal lagoons on the east coast of Australia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165862. [PMID: 37541500 DOI: 10.1016/j.scitotenv.2023.165862] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 07/08/2023] [Accepted: 07/26/2023] [Indexed: 08/06/2023]
Abstract
Acanthamoeba is an opportunistic free-living heterotrophic protist that is the most predominant amoeba in diverse ecological habitats. Acanthamoeba causes amoebic keratitis (AK), a painful and potentially blinding corneal infection. Major risk factors for AK have been linked to non-optimal contact lens hygiene practices and Acanthamoeba contamination of domestic and recreational water. This study investigated the incidence and seasonal variation of Acanthamoeba spp. within coastal lagoons located on the eastern coast of Australia and then examined the association between Acanthamoeba and water abiotic factors and bacterial species within the water. Water samples were collected from four intermittently closed and open lagoons (ICOLLs) (Wamberal, Terrigal, Avoca and Cockrone) every month between August 2019 to July 2020 except March and April. qPCR was used to target the Acanthamoeba 18S rRNA gene, validated by Sanger sequencing. Water abiotic factors were measured in situ using a multiprobe metre and 16S rRNA sequencing (V3-V4) was performed to characterise bacterial community composition. Network analysis was used to gauge putative associations between Acanthamoeba incidence and bacterial amplicon sequence variants (ASVs). Among 206 water samples analysed, 79 (38.3%) were Acanthamoeba positive and Acanthamoeba level was significantly higher in summer compared with winter, spring, or autumn (p = 0.008). More than 50% (23/45) water samples of Terrigal were positive for Acanthamoeba which is a highly urbanised area with extensive recreational activities while about 32% (16/49) samples were positive from Cockrone that is the least impacted lagoon by urban development. All sequenced strains belonged to the pathogenic genotype T4 clade except two which were of genotype clades T2 and T5. Water turbidity, temperature, intl1 gene concentration, and dissolved O2 were significantly associated with Acanthamoeba incidence (p < 0.05). The ASVs level of cyanobacteria, Pseudomonas spp., Candidatus spp., and marine bacteria of the Actinobacteria phylum and Acanthamoeba 18S rRNA genes were positively correlated (Pearson's r ≥ 0.14). The presence of Acanthamoeba spp. in all lagoons, except Wamberal, was associated with significant differences in the composition of bacterial communities (beta diversity). The results of this study suggest that coastal lagoons, particularly those in urbanised regions with extensive water recreational activities, may pose an elevated risk to human health due to the relatively high incidence of pathogenic Acanthamoeba in the summer. These findings underscore the importance of educating the public about the rare yet devastating impact of AK on vision and quality of life, highlighting the need for collaborative efforts between public health officials and educators to promote awareness and preventive measures, especially focusing lagoons residents and travellers.
Collapse
Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia.
| | - Nathan L R Williams
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Nachshon Siboni
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Kiri Rodgers
- Institute of Biomedical and Environmental Health Research, School of Health and Life Sciences, University of the West of Scotland, Blantyre, South Lanarkshire, G72 0LH, Scotland, UK
| | - Mark Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, 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, Scotland, UK
| | - Justin R Seymour
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Jaimie Potts
- Estuaries and Catchments Team, Waters Wetland Coastal Science Branch, NSW Department of Planning, Industry and Environment, Lidcombe, NSW 2141, Australia
| | - Colin Johnson
- Estuaries and Catchments Team, Waters Wetland Coastal Science Branch, NSW Department of Planning, Industry and Environment, Lidcombe, NSW 2141, Australia
| | - Peter Scanes
- Estuaries and Catchments Team, Waters Wetland Coastal Science Branch, NSW Department of Planning, Industry and Environment, Lidcombe, NSW 2141, Australia
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| |
Collapse
|
2
|
Guyard-Nicodème M, Anis N, Naguib D, Viscogliosi E, Chemaly M. Prevalence and Association of Campylobacter spp., Salmonella spp., and Blastocystis sp. in Poultry. Microorganisms 2023; 11:1983. [PMID: 37630543 PMCID: PMC10458391 DOI: 10.3390/microorganisms11081983] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023] Open
Abstract
Poultry and poultry meat are considered the most important sources of human campylobacteriosis and salmonellosis. However, data about the occurrence of Campylobacter and Salmonella concomitantly with intestinal protozoa such as Blastocystis sp. in poultry remain very scarce. Therefore, this study aimed to investigate the presence and possible interactions between these three microorganisms in fecal samples from 214 chickens collected either on farms or from live bird markets in Egypt. The results obtained showed that Campylobacter spp., Salmonella spp., and Blastocystis sp. were present in 91.6% (196/214), 44.4% (95/214), and 18.2% (39/214) of tested samples, respectively, highlighting an active circulation of these microorganisms. Moreover, a significant positive correlation was reported between the occurrence of Campylobacter spp. and Blastocystis sp. together with a significant negative correlation between Blastocystis sp. and Salmonella spp. This study confirms the association reported previously between Blastocystis sp. and Campylobacter spp. while disclosing an association between Blastocystis sp. and Salmonella spp.; it also highlights the need to improve studies on the interactions between bacteria and eukaryotes in the gut microbiota of poultry.
Collapse
Affiliation(s)
- Muriel Guyard-Nicodème
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, F-22440 Ploufragan, France; (N.A.); (M.C.)
| | - Nagham Anis
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, F-22440 Ploufragan, France; (N.A.); (M.C.)
| | - Doaa Naguib
- Department of Hygiene and Zoonoses, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt;
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Centre d’Infection et d’Immunité de Lille, University of Lille, F-59000 Lille, France;
| | - Eric Viscogliosi
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019—UMR 9017—CIIL—Centre d’Infection et d’Immunité de Lille, University of Lille, F-59000 Lille, France;
| | - Marianne Chemaly
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, F-22440 Ploufragan, France; (N.A.); (M.C.)
| |
Collapse
|
3
|
Anis N, Bonifait L, Quesne S, Baugé L, Yassine W, Guyard-Nicodème M, Chemaly M. Survival of Campylobacter jejuni Co-Cultured with Salmonella spp. in Aerobic Conditions. Pathogens 2022; 11:pathogens11070812. [PMID: 35890056 PMCID: PMC9323934 DOI: 10.3390/pathogens11070812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/11/2022] [Accepted: 07/14/2022] [Indexed: 11/28/2022] Open
Abstract
Campylobacter and Salmonella are responsible for the two major foodborne zoonotic diseases in Europe; poultry is the main infection source. Campylobacter cannot grow under aerobic conditions, but can show aerobic survival when co-cultured with other microorganisms; however, its interaction with Salmonella has not been studied yet. In this study, these two bacteria were co-cultured under controlled aerobic conditions. Different concentrations and strains of C. jejuni were incubated with or without different Salmonella serotypes (10 CFU) at 37 °C for 16 h. C. jejuni did not grow after incubation with or without Salmonella. The survival of C. jejuni was observed only for the highest initial concentration of 6 log CFU/mL with or without Salmonella. However, its survival was significantly higher when co-cultured with Salmonella. No survival was observed at lower concentrations. C. jejuni survival was positively affected by the presence of Salmonella but depended on the Salmonella serotype, the C. jejuni strain and the initial concentration. On the other hand, the Salmonella enumerations were not affected by C. jejuni. Our results suggest potential interactions between Salmonella and C. jejuni that require further investigations for a clearer understanding of their behavior in natural habitats.
Collapse
Affiliation(s)
- Nagham Anis
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, 22440 Ploufragan, France; (N.A.); (L.B.); (S.Q.); (L.B.); (M.C.)
| | - Laetitia Bonifait
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, 22440 Ploufragan, France; (N.A.); (L.B.); (S.Q.); (L.B.); (M.C.)
| | - Ségolène Quesne
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, 22440 Ploufragan, France; (N.A.); (L.B.); (S.Q.); (L.B.); (M.C.)
| | - Louise Baugé
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, 22440 Ploufragan, France; (N.A.); (L.B.); (S.Q.); (L.B.); (M.C.)
| | - Wissam Yassine
- Faculty of Sciences, Lebanese University, Beirut 10999, Lebanon;
| | - Muriel Guyard-Nicodème
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, 22440 Ploufragan, France; (N.A.); (L.B.); (S.Q.); (L.B.); (M.C.)
- Correspondence: ; Tel.: +33-296-016-211
| | - Marianne Chemaly
- Unit for Hygiene and Quality of Poultry and Pork Products, Laboratory of Ploufragan-Plouzané-Niort, ANSES, 22440 Ploufragan, France; (N.A.); (L.B.); (S.Q.); (L.B.); (M.C.)
| |
Collapse
|
4
|
Nasher F, Wren BW. Transient internalization of Campylobacter jejuni in Amoebae enhances subsequent invasion of human cells. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35175913 PMCID: PMC8941996 DOI: 10.1099/mic.0.001143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The ubiquitous unicellular eukaryote, Acanthamoeba, is known to play a role in the survival and dissemination of Campylobacter jejuni. C. jejuni is the leading cause of bacterial foodborne gastroenteritis world-wide and is a major public health problem. The ability of C. jejuni to interact and potentially invade epithelial cells is thought to be key for disease development in humans. We examined C. jejuni grown under standard laboratory conditions, 11168HCBA with that harvested from within Acanthamoeba castellanii (11168HAC/CBA) or Acanthamoeba polyphaga (11168HAP/CBA), and compared their ability to invade different cell lines. C. jejuni harvested from within amoebae had a ~3.7-fold increase in invasiveness into T84 human epithelial cells and a striking ~11-fold increase for re-entry into A. castellanii cells. We also investigated the invasiveness and survivability of six diverse representative C. jejuni strains within Acanthamoeba spp., our results confirm that invasion and survivability is likely host-cell-dependent. Our survival assay data led us to conclude that Acanthamoeba spp. are a transient host for C. jejuni and that survival within amoebae pre-adapts C. jejuni and enhances subsequent cell invasion. This study provides new insight into C. jejuni interactions with amoebae and its increased invasiveness potential in mammalian hosts.
Collapse
Affiliation(s)
- Fauzy Nasher
- London School of Hygiene and Tropical Medicine, London, UK
| | - Brendan W Wren
- London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
5
|
Shagieva E, Demnerova K, Michova H. Waterborne Isolates of Campylobacter jejuni Are Able to Develop Aerotolerance, Survive Exposure to Low Temperature, and Interact With Acanthamoeba polyphaga. Front Microbiol 2021; 12:730858. [PMID: 34777280 PMCID: PMC8578730 DOI: 10.3389/fmicb.2021.730858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/28/2021] [Indexed: 12/20/2022] Open
Abstract
Campylobacter jejuni is regarded as the leading cause of bacterial gastroenteritis around the world. Even though it is generally considered to be a sensitive microaerobic pathogen, it is able to survive in the environment outside of the intestinal tract of the host. This study aimed to assess the impact of selected environmental parameters on the survival of 14 C. jejuni isolates of different origins, including 12 water isolates. The isolates were tested for their antibiotic resistance, their ability to survive at low temperature (7°C), develop aerotolerance, and to interact with the potential protozoan host Acanthamoeba polyphaga. The antibiotic susceptibility was determined by standard disk diffusion according to EUCAST. Out of the 14 isolates, 8 were resistant to ciprofloxacin (CIP) and 5 to tetracycline (TET), while only one isolate was resistant to erythromycin (ERY). Five isolates were resistant to two different antibiotic classes. Tetracycline resistance was only observed in isolates isolated from wastewater and a clinical sample. Further, the isolates were tested for their survival at 7°C under both aerobic and microaerobic conditions using standard culture methods. The results showed that under microaerobic conditions, all isolates maintained their cultivability for 4 weeks without a significant decrease in the numbers of bacteria and variation between the isolates. However, significant differences were observed under aerobic conditions (AC). The incubation led to a decrease in the number of cultivable cells, with complete loss of cultivability after 2 weeks (one water isolate), 3 weeks (7 isolates), or 4 weeks of incubation (6 isolates). Further, all isolates were studied for their ability to develop aerotolerance by repetitive subcultivation under microaerobic and subsequently AC. Surprisingly, all isolates were able to adapt and grow under AC. As the last step, 5 isolates were selected to evaluate a potential protective effect provided by A. polyphaga. The cocultivation of isolates with the amoeba resulted in the survival of about 40% of cells treated with an otherwise lethal dose of gentamicin. In summary, C. jejuni is able to adapt and survive in a potentially detrimental environment for a prolonged period of time, which emphasizes the role of the environmental transmission route in the spread of campylobacteriosis.
Collapse
Affiliation(s)
- Ekaterina Shagieva
- Laboratory of Food Microbiology, Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czechia
| | - Katerina Demnerova
- Laboratory of Food Microbiology, Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czechia
| | - Hana Michova
- Laboratory of Food Microbiology, Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czechia
| |
Collapse
|
6
|
Amaro F, Martín-González A. Microbial warfare in the wild-the impact of protists on the evolution and virulence of bacterial pathogens. Int Microbiol 2021; 24:559-571. [PMID: 34365574 DOI: 10.1007/s10123-021-00192-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/03/2021] [Accepted: 06/28/2021] [Indexed: 01/01/2023]
Abstract
During the long history of co-evolution with protists, bacteria have evolved defense strategies to avoid grazing and survive phagocytosis. These mechanisms allow bacteria to exploit phagocytic cells as a protective niche in which to escape from environmental stress and even replicate. Importantly, these anti-grazing mechanisms can function as virulence factors when bacteria infect humans. Here, we discuss how protozoan predation exerts a selective pressure driving bacterial virulence and shaping their genomes, and how bacteria-protist interactions might contribute to the spread of antibiotic resistance as well. We provide examples to demonstrate that besides being voracious bacterial predators, protozoa can serve as melting pots where intracellular organisms exchange genetic information, or even "training grounds" where some pathogens become hypervirulent after passing through. In this special issue, we would like to emphasize the tremendous impact of bacteria-protist interactions on human health and the potential of amoebae as model systems to study biology and evolution of a variety of pathogens. Besides, a better understanding of bacteria-protist relationships will help us expand our current understanding of bacterial virulence and, likely, how pathogens emerge.
Collapse
Affiliation(s)
- Francisco Amaro
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University of Madrid, 28040, Madrid, Spain.
| | - Ana Martín-González
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University of Madrid, 28040, Madrid, Spain
| |
Collapse
|
7
|
Karki AB, Ballard K, Harper C, Sheaff RJ, Fakhr MK. Staphylococcus aureus enhances biofilm formation, aerotolerance, and survival of Campylobacter strains isolated from retail meats. Sci Rep 2021; 11:13837. [PMID: 34226590 PMCID: PMC8257638 DOI: 10.1038/s41598-021-91743-w] [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: 02/26/2021] [Accepted: 05/26/2021] [Indexed: 02/06/2023] Open
Abstract
In retail meat products, Campylobacter jejuni, C. coli, and Staphylococcus aureus have been reported in high prevalence. The polymicrobial interaction between Campylobacter and other bacteria could enhance Campylobacter survival during the adverse conditions encountered during retail meat processing and storage. This study was designed to investigate the potential role of S. aureus from retail meats in enhancing the survival of Campylobacter exposed to low temperature, aerobic conditions, and biofilm formation. Results indicated that viable S. aureus cells and filter-sterilized cell-free media obtained from S. aureus prolonged the survival of Campylobacter at low temperature and during aerobic conditions. Biofilm formation of Campylobacter strains was significantly enhanced in the presence of viable S. aureus cells, but the results were inconclusive when extracts from cell-free media were used. In conclusion, the presence of S. aureus cells enhances survivability of Campylobacter strains in adverse conditions such as low temperature and aerobic conditions. Further investigations are warranted to understand the interaction between Campylobacter and S. aureus, and effective intervention strategies are needed to reduce the incidence of both foodborne pathogens in retail meat products.
Collapse
Affiliation(s)
- Anand B. Karki
- grid.267360.60000 0001 2160 264XDepartment of Biological Science, The University of Tulsa, Tulsa, OK USA
| | - Kaylee Ballard
- grid.267360.60000 0001 2160 264XDepartment of Biological Science, The University of Tulsa, Tulsa, OK USA
| | - Claudia Harper
- grid.267360.60000 0001 2160 264XDepartment of Biological Science, The University of Tulsa, Tulsa, OK USA
| | - Robert J. Sheaff
- grid.267360.60000 0001 2160 264XDepartment of Chemistry and Biochemistry, The University of Tulsa, Tulsa, OK USA
| | - Mohamed K. Fakhr
- grid.267360.60000 0001 2160 264XDepartment of Biological Science, The University of Tulsa, Tulsa, OK USA
| |
Collapse
|
8
|
Measurable genomic changes in Mycobacterium avium subsp. hominissuis after long-term adaptation in Acanthamoeba lenticulata and reduced persistence in macrophages. J Bacteriol 2021; 203:JB.00257-20. [PMID: 33431432 PMCID: PMC8095452 DOI: 10.1128/jb.00257-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Free-living amoebae are ubiquitous in aquatic environments and act as environmental reservoirs for nontuberculous mycobacteria. Mycobacterium avium subsp. hominissuis recovered from Acanthamoeba has been demonstrated to be more virulent in both human and murine models. Here, we investigate the persistence of M. avium subsp. hominissuis after short-term (2 weeks) and long-term (42 weeks) co-culture in Acanthamoeba lenticulata We hypothesize that A. lenticulata-adapted M. avium subsp. hominissuis demonstrate phenotypic and genomic changes facilitating intracellular persistence in naïve Acanthamoeba and human macrophages. M. avium subsp. hominissuis CFU in co-culture with A. lenticulata were recorded every 2 weeks up to 60 weeks. While A. lenticulata-associated M. avium subsp. hominissuis CFU did not significantly change across 60 weeks of co-culture, longer adaptation time in amoebae reduced colony size. Isolates recovered after 2 or 42 weeks of amoebae co-culture were referred as "early-adapted" and "late-adapted" M. avium subsp. hominissuis, respectively. Whole genome sequencing was performed on amoebae-adapted isolates with pan-genome comparisons to the original M. avium subsp. hominissuis isolate. Next, amoebae-adapted isolates were assessed for their persistence in A. lenticulata, A. castellanii, and human THP-1 macrophages. Multiplex cytokine/chemokine analyses were conducted on THP-1 culture supernatants. Compared to the original isolate, counts of late-adapted M. avium subsp. hominissuis were reduced in Acanthamoeba and contrary to expectations, lower counts were also observed in THP-1 macrophages with concomitant decrease in TNFa, IL-6, and MIP-1b suggesting that host adaptation may influence the inflammatory properties of M. avium IMPORTANCE Short-term interaction between Acanthamoeba and M. avium has been demonstrated to increase infectivity in human and murine models of infection, establishing the paradigm that amoebae "train" M. avium in the environment by selecting for phenotypes capable of enduring in human cells. We investigate this phenomenon further by determining the consequence of long-term amoebae adaptation on M. avium subsp. hominissuis persistence in host cells. We monitored genomic changes across long-term Acanthamoeba co-culture and report significant changes to the M. avium subsp. hominissuis genome in response to amoebae-adaptation and reduced colony size. Furthermore, we examined isolates co-cultured with A. lenticulata for 2 or 42 weeks and provide biological evidence that long-term co-culture in amoebae reduces M. avium persistence in human macrophages.
Collapse
|
9
|
George AS, Rehfuss MYM, Parker CT, Brandl MT. The transcriptome of Escherichia coli O157: H7 reveals a role for oxidative stress resistance in its survival from predation by Tetrahymena. FEMS Microbiol Ecol 2020; 96:5721237. [PMID: 32009174 DOI: 10.1093/femsec/fiaa014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 11/14/2022] Open
Abstract
Pathogenic E. coli remains undigested upon phagocytosis by Tetrahymena and is egested from the ciliate as viable cells in its fecal pellets. Factors that are involved in the survival of Shiga toxin-producing E. coli serovar O157: H7 (EcO157) from digestion by Tetrahymena were identified by microarray analysis of its transcriptome in the protozoan phagosome. Numerous genes belonging to anaerobic metabolism and various stress responses were upregulated significantly ≥ 2-fold in EcO157 cells in the food vacuoles compared with in planktonic cells that remained uningested by the protist. Among these were the oxidative stress response genes, ahpF and katG. Fluorescence microscopy and staining with CellROX® Orange confirmed the presence of reactive oxygen species in food vacuoles containing EcO157 cells. Frequency distribution analysis of the percentage of EcO157 viable cells in Tetrahymena fecal pellets revealed that the ΔahpCF and ΔahpCFΔkatG mutants were less fit than the wild type strain and ΔkatG mutant after passage through the protist. Given the broad use of oxidants as sanitizers in the food industry, our observation of the oxidative stress response in EcO157 during its interaction with Tetrahymena emphasizes the importance of furthering our knowledge of the physiology of this human pathogen in environments relevant to its ecology and to food safety.
Collapse
Affiliation(s)
- Andree Sherlon George
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Marc Yi Ming Rehfuss
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Craig Thomas Parker
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Maria Theresa Brandl
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| |
Collapse
|
10
|
Moreno-Mesonero L, Ferrús MA, Moreno Y. Determination of the bacterial microbiome of free-living amoebae isolated from wastewater by 16S rRNA amplicon-based sequencing. ENVIRONMENTAL RESEARCH 2020; 190:109987. [PMID: 32771367 DOI: 10.1016/j.envres.2020.109987] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 06/11/2023]
Abstract
Free-living amoebae (FLA) are ubiquitous protozoa commonly found in water. FLA are well-established hosts for amoeba-resistant bacteria, most of which are pathogenic, and offer them shelter from adverse environmental conditions or water treatments. Since there is very little knowledge about the complete bacterial microbiome of FLA, in this work the bacterial microbiome of FLA isolated from wastewater both after secondary and tertiary treatments was studied by amplicon-based sequencing. FLA were detected in 87.5% and 50.0% of wastewater samples taken after secondary and tertiary disinfection treatments, respectively. The most abundant bacterial phyla were Proteobacteria, Planctomycetes, Bacteroidetes and Firmicutes, which represented 83.77% of the total bacterial FLA microbiome. The most abundant class of bacteria was Gammaproteobacteria, which contains an important number of relevant pathogenic bacteria. The bacteria of public health concern Aeromonas, Arcobacter, Campylobacter, Helicobacter, Klebsiella, Legionella, Mycobacterium, Pseudomonas and Salmonella were detected as part of the FLA microbiome. Although different microbial communities were identified in each sample, there is no correlation between the microbiome of FLA and the extent of wastewater treatment. To our knowledge, this is the first work in which the bacterial microbiome of FLA isolated from wastewater is studied. Obtained results indicate that FLA are hosts of potentially pathogenic bacteria in treated wastewater used for irrigation, which may pose a public health threat.
Collapse
Affiliation(s)
- Laura Moreno-Mesonero
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022, Valencia, Spain.
| | - María Antonia Ferrús
- Biotechnology Department, Universitat Politècnica de València, 46022, Valencia, Spain.
| | - Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, 46022, Valencia, Spain.
| |
Collapse
|
11
|
Hojo F, Osaki T, Yonezawa H, Hanawa T, Kurata S, Kamiya S. Acanthamoeba castellanii supports extracellular survival of Helicobacter pylori in co-culture. J Infect Chemother 2020; 26:946-954. [PMID: 32448734 DOI: 10.1016/j.jiac.2020.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/03/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022]
Abstract
This study aimed to demonstrate whether Helicobacter pylori is able to survive in co-culture with a protozoan, Acanthamoeba castellanii, in order to further investigate a possible aqueous environmental mode of transmission. Numbers of H. pylori in co-culture with A castellanii were assessed by colony forming unit (CFU) assay and cell morphology was observed by electron microscopy. Viable and intact H. pylori in co-culture were detected and the number of H. pylori in co-culture with A. castellanii was significantly higher than in bacterial single culture. It was also shown that co-culture of H. pylori with A. castellanii physically separated by a filter membrane negated this survival effect, suggesting that adherence of H. pylori to A. castellanii affects its survival. Scanning electron microscopy revealed helical forms of H. pylori in co-culture with A. castellanii, but not in single culture. These results imply that mutual interaction between H. pylori and A. castellanii in the environment is critical for survival of H. pylori. In addition, the H. pylori gene expression profile was found to differ between single and co-cultured cells using RNA-sequence analysis.
Collapse
Affiliation(s)
- Fuhito Hojo
- Institute of Laboratory Animals, Graduate School of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka, Tokyo, Japan.
| | - Takako Osaki
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, Japan
| | - Hideo Yonezawa
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, Japan
| | - Tomoko Hanawa
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, Japan
| | - Satoshi Kurata
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, Japan
| | - Shigeru Kamiya
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo, Japan; Faculty of Health Sciences, Kyorin University, 181-8612, 5-4-1 Shimorenjaku, Mitaka, Tokyo, Japan
| |
Collapse
|
12
|
Moreno Y, Moreno-Mesonero L, García-Hernández J. DVC-FISH to identify potentially pathogenic Legionella inside free-living amoebae from water sources. ENVIRONMENTAL RESEARCH 2019; 176:108521. [PMID: 31195295 DOI: 10.1016/j.envres.2019.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/11/2019] [Accepted: 06/01/2019] [Indexed: 06/09/2023]
Abstract
Despite all safety efforts, drinking and wastewater can still be contaminated by Legionella and free-living amoebae (FLA) since these microorganisms are capable of resisting disinfection treatments. An amoebae cyst harboring pathogenic Legionella spp. can be a transporter of this organism, protecting it and enhancing its infection abilities. Therefore, the aim of this work is to identify by DVC-FISH viable Legionella spp and Legionella pneumophila cells inside FLA from water sources in a specific and rapid way with the aim of assessing the real risk of these waters. A total of 55 water samples were processed, 30 reclaimed wastewater and 25 drinking water. FLA presence was detected in 52.7% of the total processed water samples. When DVC-FISH technique was applied, the presence of viable internalized Legionella spp. cells was identified in 69.0% of the total FLA-positive samples, concretely in 70.0% and 66.7% of wastewater and drinking water samples, respectively. L. pneumophila was simultaneously identified in 48.3% of the total FLA-positive samples, specifically in 50.0% and 44.4% of wastewater and drinking water samples, respectively. By culture, potentially pathogenic Legionella cells were recovered in 27.6% of the total FLA-positive bacteria, particularly in 35.0% and 11.1% of wastewater and drinking water samples, respectively. These findings demonstrate that FLA may promote resistance of bacteria to the performed disinfection treatments for drinking as well as for wastewater. So, in addition to the risk for the presence of pathogenic FLA in water it is necessary to take into account that these can be transporters of the pathogenic bacteria Legionella, which are able to survive inside them. The DVC-FISH method described here has been proved to be a rapid and specific tool to identify pathogenic Legionella spp. and L. penumophila viable cells harboured by FLA in these water sources, posing particular public health concern.
Collapse
Affiliation(s)
- Y Moreno
- Research Institute of Water and Environmental Ingeneering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain.
| | - L Moreno-Mesonero
- Research Institute of Water and Environmental Ingeneering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain
| | - J García-Hernández
- Biotechnology Department, Universitat Politècnica de València, 46022 Valencia, Spain
| |
Collapse
|
13
|
Purple K, Amacker T, Williams C, Gerhold R. Artificially decreased dissolved oxygen increases the persistence of Trichomonas gallinae in water. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2019; 9:100-103. [PMID: 31011532 PMCID: PMC6463543 DOI: 10.1016/j.ijppaw.2019.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 11/30/2022]
Abstract
Water containing organic material has been shown to increase the persistence of the avian pathogenic protozoa, Trichomonas gallinae. We hypothesized that the decrease in dissolved oxygen due to microbes in the organic material could increase persistence of the microaerophilic trichomonads. Using simulated birdbaths, we determined 1) the levels of dissolved oxygen in distilled water with various amounts of organic material, 2) the concentration of the oxygen-scavenging enzyme Oxyrase® needed to achieve the dissolved oxygen levels obtained in organic material contaminated water, and finally, 3) the persistence of two T. gallinae isolates in Oxyrase®-supplemented water. An average of 9.6% dissolved oxygen was obtained with the addition of 15 g organic material to 500 ml of distilled water, whereas organic material-free water had 86.2% dissolved oxygen. The addition of 0.5% and 1.0% (vol/vol) Oxyrase® to organic material-free water yielded dissolved oxygen of 18.6% and 6.9%, respectively. Using 0.5% and 1.0% concentrations of Oxyrase®, we evaluated the persistence of two trichomonad isolates by inoculating ∼1 million trichomonads into 500 ml distilled water in triplicate. At various time-points, 0.5 ml aliquots of trichomonad-inoculated water were obtained and placed into Hollander Fluid media, incubated at 37 °C, and read by light microscopy every other day for 5 days. In our 1% Oxyrase® treatments, the longest recorded persistence of broad-winged hawk 1 increased from the previously reported 4hrs to 30hrs and Cooper's hawk 4 from 16hrs to 30hrs. These results indicate that the mechanism for organic material-mediated trichomonad persistence is associated with decreased dissolved oxygen, further demonstrating the importance of keeping birdbaths free of organic debris to discourage trichomonad persistence. Low (9.6%) dissolved oxygen (DO) levels were achieved in waterers with addition of organic material (OM). Addition of 1% Oxyrase resulted in similar DO findings (6.9%) with a pH of 7.24 Lower DO is likely mechanism of increased Trichomonas gallinae persistence in waterers with OM. Results underscore the need to keep bird waterers clean to minimize T. gallinae transmission.
Collapse
Affiliation(s)
- Kathryn Purple
- Comparative and Experimental Medicine, University of Tennessee College of Veterinary Medicine, 2407 River Drive, Knoxville, TN, 37996, USA.,Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, 2407 River Drive, Knoxville, TN, 37996, USA
| | - Todd Amacker
- Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, 274 Ellington Plant Sciences Building, Knoxville, TN, 37996, USA
| | - Chauntelle Williams
- Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, 274 Ellington Plant Sciences Building, Knoxville, TN, 37996, USA
| | - Richard Gerhold
- Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, 2407 River Drive, Knoxville, TN, 37996, USA.,Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, 274 Ellington Plant Sciences Building, Knoxville, TN, 37996, USA
| |
Collapse
|
14
|
Maal-Bared R, Dixon B, Axelsson-Olsson D. Fate of internalized Campylobacter jejuni and Mycobacterium avium from encysted and excysted Acanthamoeba polyphaga. Exp Parasitol 2019; 199:104-110. [PMID: 30902623 DOI: 10.1016/j.exppara.2019.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
Abstract
Association of the water- and foodborne pathogen Campylobacter jejuni with free-living Acanthamoeba spp. trophozoites enhances C. jejuni survival and resistance to biocides and starvation. When facing less than optimal environmental conditions, however, the Acanthamoeba spp. host can temporarily transform from trophozoite to cyst and back to trophozoite, calling the survival of the internalized symbiont and resulting public health risk into question. Studies investigating internalized C. jejuni survival after A. castellanii trophozoite transformation have neither been able to detect its presence inside the Acanthamoeba cyst after encystation nor to confirm its presence upon excystation of trophozoites through culture-based techniques. The purpose of this study was to detect C. jejuni and Mycobacterium avium recovered from A. polyphaga trophozoites after co-culture and induction of trophozoite encystation using three different encystation methods (Neff's medium, McMillen's medium and refrigeration), as well as after cyst excystation. Internalized M. avium was used as a positive control, since studies have consistently detected the organism after co-culture and after host excystation. Concentrations of C. jejuni in A. polyphaga trophozoites were 4.5 × 105 CFU/ml, but it was not detected by PCR or culture post-encystation. This supports the hypothesis that C. jejuni may be digested during encystation of the amoebae. M. avium was recovered at a mean concentration of 1.9 × 104 from co-cultured trophozoites and 4.4 × 101 CFU/ml after excystation. The results also suggest that M. avium recovery post-excystation was statistically significantly different based on which encystation method was used, ranging from 1.3 × 101 for Neff's medium to 5.4 × 101 CFU/ml for refrigeration. No M. avium was recovered from A. polyphaga cysts when trophozoites were encysted by McMillen's medium. Since C. jejuni internalized in cysts would be more likely to survive harsh environmental conditions and disinfection, a better understanding of potential symbioses between free-living amoebae and campylobacters in drinking water distribution systems and food processing environments is needed to protect public health. Future co-culture experiments examining survival of internalized C. jejuni should carefully consider the encystation media used, and include molecular detection tools to falsify the hypothesis that C. jejuni may be present in a viable but not culturable state.
Collapse
Affiliation(s)
- Rasha Maal-Bared
- Centre for Research on Environmental Microbiology, University of Ottawa, Faculty of Medicine, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
| | - Brent Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Canada, Ottawa, ON, K1A 0K9, Canada.
| | - Diana Axelsson-Olsson
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
| |
Collapse
|
15
|
Divalent Metal Cations Potentiate the Predatory Capacity of Amoeba for Cryptococcus neoformans. Appl Environ Microbiol 2018; 84:AEM.01717-17. [PMID: 29150507 DOI: 10.1128/aem.01717-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 11/07/2017] [Indexed: 01/19/2023] Open
Abstract
Among the best-studied interactions between soil phagocytic predators and a human-pathogenic fungus is that of Acanthamoeba castellanii and Cryptococcus neoformans The experimental conditions used in amoeba-fungus confrontation assays can have major effects on whether the fungus or the protozoan is ascendant in the interaction. In the presence of Mg2+ and Ca2+ in phosphate-buffered saline (PBS), C. neoformans was consistently killed when incubated with A. castellaniiA. castellanii survived better in the presence of Mg2+ and Ca2+, even when incubated with C. neoformans In the absence of Mg2+ and Ca2+, C. neoformans survived when incubated with A. castellanii, and the percentage of dead amoebae was higher than when incubated without yeast cells. These results show that the presence of Mg2+ and Ca2+ can make a decisive contribution toward tilting the outcome of the interaction in favor of the amoeba. Of the two metals, Mg2+ had a stronger effect than Ca2+ The cations enhanced A. castellanii activity against C. neoformans via enhanced phagocytosis, which is the major mechanism by which amoebae kill fungal cells. We found no evidence that amoebae use extracellular killing mechanisms in their interactions with C. neoformans In summary, the presence of Mg2+ and Ca2+ enhanced the cell adhesion on the surfaces and the motility of the amoeba, thus increasing the chance for contact with C. neoformans and the frequency of phagocytosis. Our findings imply that the divalent cation concentration in soils could be an important variable for whether amoebae can control C. neoformans in the environment.IMPORTANCE The grazing of soil organisms by phagocytic predators such as amoebae is thought to select for traits that enable some of them to acquire the capacity for virulence in animals. Consequently, knowledge about the interactions between amoebae and soil microbes, such as pathogenic fungi, is important for understanding how virulence can emerge. We show that the interaction between an amoeba and the pathogenic fungus C. neoformans is influenced by the presence in the assay of magnesium and calcium, which potentiate amoebae. The results may also have practical applications, since enriching soils with divalent cations may reduce C. neoformans numbers in contaminated soils.
Collapse
|
16
|
CmeABC Multidrug Efflux Pump Contributes to Antibiotic Resistance and Promotes Campylobacter jejuni Survival and Multiplication in Acanthamoeba polyphaga. Appl Environ Microbiol 2017; 83:AEM.01600-17. [PMID: 28916560 PMCID: PMC5666138 DOI: 10.1128/aem.01600-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/09/2017] [Indexed: 12/30/2022] Open
Abstract
Campylobacter jejuni is a foodborne pathogen that is recognized as the leading cause of human bacterial gastroenteritis. The widespread use of antibiotics in medicine and in animal husbandry has led to an increased incidence of antibiotic resistance in Campylobacter In addition to a role in multidrug resistance (MDR), the Campylobacter CmeABC resistance-nodulation-division (RND)-type efflux pump may be involved in virulence. As a vehicle for pathogenic microorganisms, the protozoan Acanthamoeba is a good model for investigations of bacterial survival in the environment and the molecular mechanisms of pathogenicity. The interaction between C. jejuni 81-176 and Acanthamoeba polyphaga was investigated in this study by using a modified gentamicin protection assay. In addition, a possible role for the CmeABC MDR pump in this interaction was explored. Here we report that this MDR pump is beneficial for the intracellular survival and multiplication of C. jejuni in A. polyphaga but is dispensable for biofilm formation and motility.IMPORTANCE The endosymbiotic relationship between amoebae and microbial pathogens may contribute to persistence and spreading of the latter in the environment, which has significant implications for human health. In this study, we found that Campylobacter jejuni was able to survive and to multiply inside Acanthamoeba polyphaga; since these microorganisms can coexist in the same environment (e.g., on poultry farms), the latter may increase the risk of infection with Campylobacter Our data suggest that, in addition to its role in antibiotic resistance, the CmeABC MDR efflux pump plays a role in bacterial survival within amoebae. Furthermore, we demonstrated synergistic effects of the CmeABC MDR efflux pump and TetO on bacterial resistance to tetracycline. Due to its role in both the antibiotic resistance and the virulence of C. jejuni, the CmeABC MDR efflux pump could be considered a good target for the development of antibacterial drugs against this pathogen.
Collapse
|
17
|
Moreno-Mesonero L, Moreno Y, Alonso JL, Ferrús MA. Detection of viable Helicobacter pylori inside free-living amoebae in wastewater and drinking water samples from Eastern Spain. Environ Microbiol 2017; 19:4103-4112. [PMID: 28707344 DOI: 10.1111/1462-2920.13856] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/29/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022]
Abstract
Helicobacter pylori is one of the most concerning emerging waterborne pathogens. It has been suggested that it could survive in water inside free-living amoebae (FLA), but nobody has studied this relationship in the environment yet. Thus, we aimed to detect viable H. pylori cells from inside FLA in water samples. Sixty-nine wastewater and 31 drinking water samples were collected. FLA were purified and identified by PCR and sequencing. For exclusively detecting H. pylori inside FLA, samples were exposed to sodium hypochlorite and assayed by specific PMA-qPCR, DVC-FISH and culture. FLA were detected in 38.7% of drinking water and 79.7% of wastewater samples, even after disinfection. In wastewater, Acanthamoeba spp. and members of the family Vahlkampfiidae were identified. In drinking water, Acanthamoeba spp. and Echinamoeba and/or Vermamoeba were present. In 39 (58.2%) FLA-positive samples, H. pylori was detected by PMA-qPCR. After DVC-FISH, 21 (31.3%) samples harboured viable H. pylori internalized cells. H. pylori was cultured from 10 wastewater samples. To our knowledge, this is the first report that demonstrates that H. pylori can survive inside FLA in drinking water and wastewater, strongly supporting the hypothesis that FLA could play an important role in the transmission of H. pylori to humans.
Collapse
Affiliation(s)
- Laura Moreno-Mesonero
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Valencia 46022, Spain
| | - Yolanda Moreno
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Valencia 46022, Spain
| | - José Luis Alonso
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Valencia 46022, Spain
| | - M Antonia Ferrús
- Research Institute of Water and Environmental Engineering (IIAMA), Universitat Politècnica de València, Valencia 46022, Spain.,Biotechnology Department, Universitat Politècnica de València, Valencia 46022, Spain
| |
Collapse
|
18
|
Santos SS, Hendriksen NB, Jakobsen HH, Winding A. Effects of Bacillus cereus Endospores on Free-Living Protist Growth. MICROBIAL ECOLOGY 2017; 73:699-709. [PMID: 27928597 DOI: 10.1007/s00248-016-0905-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/27/2016] [Indexed: 06/06/2023]
Abstract
We studied the predator-prey interactions between heterotrophic protists and endospores of Bacillus cereus group bacteria, in order to gain insight on survival and dispersal of B. cereus endospores in the environment. It has been hypothesised that the spore stage protects against digestion by predating protists. Therefore, experiments were carried out to investigate the impact of B. cereus endospores and vegetative cells, as the only food source, on individual amoeboid, flagellated and ciliated protists. The presence of fluorescent-labelled intracellular bacteria confirmed that B. cereus endospores as well as vegetative cells were ingested by protists and appeared intact in the food vacuoles when observed by epifluorescence microscopy. Furthermore, protist growth and bacterial predation were followed by qPCR. Protists were able to grow on vegetative cells as well as endospores of B. cereus, despite the lower cell division rates observed for some protists when feeding on bacterial endospores. Survival and proliferation of ingested bacteria inside protists cells was also observed. Finally, B. cereus spore germination and growth was observed within all protists with higher abundance in the amoeboid protist after antibiotic treatment of the protist surface. These observations support that protists can act as a potential breeding ground for B. cereus endospores.
Collapse
Affiliation(s)
- Susana S Santos
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Niels Bohse Hendriksen
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | | | - Anne Winding
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark.
| |
Collapse
|
19
|
Noinarin P, Chareonsudjai P, Wangsomnuk P, Wongratanacheewin S, Chareonsudjai S. Environmental Free-Living Amoebae Isolated from Soil in Khon Kaen, Thailand, Antagonize Burkholderia pseudomallei. PLoS One 2016; 11:e0167355. [PMID: 27898739 PMCID: PMC5127566 DOI: 10.1371/journal.pone.0167355] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 11/11/2016] [Indexed: 11/18/2022] Open
Abstract
Presence of Burkholderia pseudomallei in soil and water is correlated with endemicity of melioidosis in Southeast Asia and northern Australia. Several biological and physico-chemical factors have been shown to influence persistence of B. pseudomallei in the environment of endemic areas. This study was the first to evaluate the interaction of B. pseudomallei with soil amoebae isolated from B. pseudomallei-positive soil site in Khon Kaen, Thailand. Four species of amoebae, Paravahlkampfia ustiana, Acanthamoeba sp., Naegleria pagei, and isolate A-ST39-E1, were isolated, cultured and identified based on morphology, movement and 18S rRNA gene sequence. Co-cultivation combined with a kanamycin-protection assay of B. pseudomallei with these amoebae at MOI 20 at 30°C were evaluated during 0–6 h using the plate count technique on Ashdown’s agar. The fate of intracellular B. pseudomallei in these amoebae was also monitored by confocal laser scanning microscopy (CLSM) observation of the CellTracker™ Orange-B. pseudomallei stained cells. The results demonstrated the ability of P. ustiana, Acanthamoeba sp. and isolate A-ST39-E1 to graze B. pseudomallei. However, the number of internalized B. pseudomallei substantially decreased and the bacterial cells disappeared during the observation period, suggesting they had been digested. We found that B. pseudomallei promoted the growth of Acanthamoeba sp. and isolate A-ST39-E1 in co-cultures at MOI 100 at 30°C, 24 h. These findings indicated that P. ustiana, Acanthamoeba sp. and isolate A-ST39-E1 may prey upon B. pseudomallei rather than representing potential environmental reservoirs in which the bacteria can persist.
Collapse
Affiliation(s)
- Parumon Noinarin
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
| | - Pisit Chareonsudjai
- Department of Environmental Science, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Biofilm Research Group, Khon Kaen University, Khon Kaen, Thailand
| | - Pinich Wangsomnuk
- Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Surasak Wongratanacheewin
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
| | - Sorujsiri Chareonsudjai
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand
- Biofilm Research Group, Khon Kaen University, Khon Kaen, Thailand
- * E-mail:
| |
Collapse
|
20
|
Trigui H, Paquet VE, Charette SJ, Faucher SP. Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis. Appl Environ Microbiol 2016; 82:2783-90. [PMID: 26921427 PMCID: PMC4836424 DOI: 10.1128/aem.03921-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/23/2016] [Indexed: 12/23/2022] Open
Abstract
Campylobacter jejuniis the leading cause of bacterial gastroenteritis worldwide. Transmission to humans occurs through consumption of contaminated food or water. The conditions affecting the persistence of C. jejuniin the environment are poorly understood. Some protozoa package and excrete bacteria into multilamellar bodies (MLBs). Packaged bacteria are protected from deleterious conditions, which increases their survival. We hypothesized that C. jejuni could be packaged under aerobic conditions by the amoeba Acanthamoeba castellanii or the ciliate Tetrahymena pyriformis, both of which are able to package other pathogenic bacteria.A. castellanii did not produce MLBs containing C. jejuni In contrast, when incubated with T. pyriformis,C. jejuni was ingested, packaged in MLBs, and then expelled into the milieu. The viability of the bacteria inside MLBs was confirmed by microscopic analyses. The kinetics of C. jejuni culturability showed that packaging increased the survival of C. jejuniup to 60 h, in contrast to the strong survival defect seen in ciliate-free culture. This study suggests that T. pyriformis may increase the risk of persistence of C. jejuniin the environment and its possible transmission between different reservoirs in food and potable water through packaging.
Collapse
Affiliation(s)
- Hana Trigui
- McGill University, Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Quebec City, QC, Canada Département de Biochimie, de Microbiologie, et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Quebec City, QC, Canada Département de Biochimie, de Microbiologie, et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
| | - Sébastien P Faucher
- McGill University, Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| |
Collapse
|
21
|
Moreno-Mesonero L, Moreno Y, Alonso JL, Ferrús MA. DVC-FISH and PMA-qPCR techniques to assess the survival of Helicobacter pylori inside Acanthamoeba castellanii. Res Microbiol 2016; 167:29-34. [PMID: 26342651 DOI: 10.1016/j.resmic.2015.08.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 08/13/2015] [Accepted: 08/19/2015] [Indexed: 10/23/2022]
|
22
|
Culotti A, Packman AI. Pseudomonas aeruginosafacilitatesCampylobacter jejunigrowth in biofilms under oxic flow conditions. FEMS Microbiol Ecol 2015; 91:fiv136. [DOI: 10.1093/femsec/fiv136] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2015] [Indexed: 11/14/2022] Open
|
23
|
Lambrecht E, Baré J, Chavatte N, Bert W, Sabbe K, Houf K. Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria. Appl Environ Microbiol 2015; 81:5604-12. [PMID: 26070667 PMCID: PMC4510183 DOI: 10.1128/aem.01031-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/04/2015] [Indexed: 12/26/2022] Open
Abstract
The production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica, Escherichia coli, Yersinia enterocolitica, and Listeria monocytogenes) survive inside cysts of the ubiquitous amoeba Acanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, with Salmonella enterica surviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed.
Collapse
Affiliation(s)
- Ellen Lambrecht
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Julie Baré
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Natascha Chavatte
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Wim Bert
- Nematology Research Unit, Department of Biology, Ghent University, Ghent, Belgium
| | - Koen Sabbe
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
| | - Kurt Houf
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| |
Collapse
|
24
|
Vieira A, Seddon AM, Karlyshev AV. Campylobacter-Acanthamoeba interactions. MICROBIOLOGY-SGM 2015; 161:933-947. [PMID: 25757600 DOI: 10.1099/mic.0.000075] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/09/2015] [Indexed: 02/02/2023]
Abstract
Campylobacter jejuni is a foodborne pathogen recognized as the major cause of human bacterial enteritis. Undercooked poultry products and contaminated water are considered as the most important sources of infection. Some studies suggest transmission and survival of this bacterial pathogen may be assisted by the free-living protozoa Acanthamoeba. The latter is known to play the role of a host for various pathogenic bacteria, protecting them from harsh environmental conditions. Importantly, there is a similarity between the mechanisms of bacterial survival within amoebae and macrophages, making the former a convenient tool for the investigation of the survival of pathogenic bacteria in the environment. However, the molecular mechanisms involved in the interaction between Campylobacter and Acanthamoeba are not well understood. Whilst some studies suggest the ability of C. jejuni to survive within the protozoa, the other reports support an extracellular mode of survival only. In this review, we focus on the studies investigating the interaction between Campylobacter and Acanthamoeba, address some reasons for the contradictory results, and discuss possible implications of these results for epidemiology. Additionally, as the molecular mechanisms involved remain unknown, we also suggest possible factors that may be involved in this process. Deciphering the molecular mechanisms of pathogen-protozoa interaction will assist in a better understanding of Campylobacter lifestyle and in the development of novel antibacterial drugs.
Collapse
Affiliation(s)
- Ana Vieira
- Faculty of Science, Engineering and Computing, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, UK
| | - Alan M Seddon
- Faculty of Science, Engineering and Computing, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, UK
| | - Andrey V Karlyshev
- Faculty of Science, Engineering and Computing, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey KT1 2EE, UK
| |
Collapse
|
25
|
Kao PM, Hsu BM, Hsu TK, Liu JH, Chang HY, Ji WT, Tzeng KJ, Huang SW, Huang YL. Seasonal distribution of potentially pathogenic Acanthamoeba species from drinking water reservoirs in Taiwan. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:3766-3773. [PMID: 25263419 DOI: 10.1007/s11356-014-3651-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 09/22/2014] [Indexed: 06/03/2023]
Abstract
In order to detect the presence/absence of Acanthamoeba along with geographical variations, water quality variations and seasonal change of Acanthamoeba in Taiwan was investigated by 18S ribosomal RNA (rRNA) gene TaqMan quantitative real-time PCR. Samples were collected quarterly at 19 drinking water reservoir sites from November 2012 to August 2013. Acanthamoeba was detected in 39.5 % (30/76) of the water sample, and the detection rate was 63.2 % (12/19) from samples collected in autumn. The average concentration of Acanthamoeba was 3.59 × 10(4) copies/L. For geographic distribution, the detection rate for Acanthamoeba at the northern region was higher than the central and southern regions in all seasons. Results of Spearman rank test revealed that heterotrophic plate count (HPC) had a negative correlation (R = -0.502), while dissolved oxygen (DO) had a positive correlation (R = 0.463) in summer. Significant differences were found only between the presence/absence of Acanthamoeba and HPC in summer (Mann-Whitney U test, P < 0.05). T2 and T4 genotypes of Acanthamoeba were identified, and T4 was the most commonly identified Acanthamoeba genotypes. The presence of Acanthamoeba in reservoirs presented a potential public health threat and should be further examined.
Collapse
Affiliation(s)
- Po-Min Kao
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Larsen MH, Dalmasso M, Ingmer H, Langsrud S, Malakauskas M, Mader A, Møretrø T, Smole Možina S, Rychli K, Wagner M, John Wallace R, Zentek J, Jordan K. Persistence of foodborne pathogens and their control in primary and secondary food production chains. Food Control 2014. [DOI: 10.1016/j.foodcont.2014.03.039] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
27
|
Vaerewijck MJ, Baré J, Lambrecht E, Sabbe K, Houf K. Interactions of Foodborne Pathogens with Free-living Protozoa: Potential Consequences for Food Safety. Compr Rev Food Sci Food Saf 2014. [DOI: 10.1111/1541-4337.12100] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Julie Baré
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| | - Ellen Lambrecht
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| | - Koen Sabbe
- Laboratory of Protistology and Aquatic Ecology; Dept. of Biology, Ghent Univ; Belgium
| | - Kurt Houf
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| |
Collapse
|
28
|
Development of a modified gentamicin protection assay to investigate the interaction between Campylobacter jejuni and Acanthamoeba castellanii ATCC 30010. Exp Parasitol 2014; 140:39-43. [PMID: 24632191 DOI: 10.1016/j.exppara.2014.03.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/28/2014] [Accepted: 03/05/2014] [Indexed: 11/21/2022]
Abstract
Campylobacter jejuni is one of the leading causes of diarrheal illness worldwide. It is persistent in the environment and on poultry despite its microaerophilic nature and sensitivity to dessication and pH. Studies have demonstrated that C. jejuni co-incubated with Acanthamoeba spp. may be protected from harmful environmental factors. Research in this area, however has included a range of different methodologies for co-incubation, recovery of bacteria and amoebae, and verification of internalization. In this study a modified gentamicin protection assay (mGPA) was developed with a standardized co-incubation procedure. The mGPA addresses limitations of the traditional GPA by providing quantification of the rate of internalization, or lack of internalization, of C. jejuni by Acanthamoeba castellanii. The mGPA described here utilizes tubes instead of cell culture plates allowing for determination of exact numbers of A. castellanii and C. jejuni to be co-incubated prior to addition to tubes. Additionally, the mGPA allows for the incorporation of C. jejuni-only controls to determine the fate of C. jejuni throughout the assay in the absence of A. castellanii. Using the mGPA it was determined that on average 1.6×10(5) C. jejuni (or 0.006% of initial 1×10(9) inoculum) survive the assay in the absence of A. castellanii. Additionally, results obtained with the mGPA demonstrated that while co-incubation with amoebae sometimes (56% of co-incubations) provided a protective effect for C. jejuni, in other cases it did not provide any protective effect (39% of co-incubations), and in at least one case there was a statistically significant higher recovery of C. jejuni in controls when compared to C. jejuni co-incubated with amoebae. The modified gentamicin protection assay described here allows better quantification of the rate and incidence of internalization of bacteria by amoebae. Use of the standardized mGPA developed here with varying environmental parameters and/or strains of bacteria and amoebae may provide insight into factors which are involved in the initiation of internalization of bacteria by amoebae.
Collapse
|
29
|
Goñi P, Fernández MT, Rubio E. Identifying endosymbiont bacteria associated with free-living amoebae. Environ Microbiol 2014; 16:339-49. [PMID: 24422686 DOI: 10.1111/1462-2920.12363] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 12/17/2013] [Accepted: 12/17/2013] [Indexed: 11/30/2022]
Abstract
The association between free-living amoebae and pathogenic bacteria is an issue that has gained great importance due to the environmental and health consequences that it implies. In this paper, we analyse the techniques to follow an epidemiological study to identify associations between genera, species, genotypes and subgenotypes of amoebae with pathogenic bacteria, analysing their evolution and considering their usefulness. In this sense, we highlight the combination of microscopic and molecular techniques as the most appropriate way to obtain fully reliable results as well as the need to achieve the standardization of these techniques to allow the comparison of both environmental and clinical results.
Collapse
Affiliation(s)
- Pilar Goñi
- Area of Parasitology, University of Zaragoza, Zaragoza, Spain
| | | | | |
Collapse
|
30
|
Free-living amoebae recovered from human stool samples in Strongyloides agar culture. J Clin Microbiol 2013; 52:699-700. [PMID: 24478518 DOI: 10.1128/jcm.02738-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
31
|
Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila. Parasit Vectors 2013; 6:169. [PMID: 23742105 PMCID: PMC3682894 DOI: 10.1186/1756-3305-6-169] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/27/2013] [Indexed: 11/15/2022] Open
Abstract
Background Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts. Methods Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with and invasion of A. castellanii. Additionally, bacterial survival intracellular of A. castellanii trophozoites as well as cysts was determined. Results All three bacterial isolates tested, associated, invaded, and survived inside A. castellanii trophozoites as well as A. castellanii cysts. However, E. aerogenes and E. coli exhibited significantly reduced association with and invasion of A. castellanii as compared with A. hydrophila (P < 0.01 using paired T-test, one tail distribution). In the long term survival assays, all three bacterial isolates tested remained viable inside A. castellanii trophozoites, while amoeba remained intact; however A. hydrophila exhibited higher survival inside amoebae (14.54 ± 3.3 bacteria:amoeba ratio) compared with E. aerogenes (3.96 ± 0.7 bacteria:amoeba ratio) and E. coli (5.85 ± 1.1 bacteria:amoeba ratio). A. hydrophila, E. coli, and E. aerogenes remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (14.13 ± 0.89 A. hydrophila:amoeba ratio, 10.13 ± 1.17 E. aerogenes:amoeba ratio, and 11.95 ± 0.7 E. coli:amoeba ratio). Conclusions A. hydrophila and E. aerogenes also joined the ranks of other bacteria that could benefit from A. castellanii. Because cysts can be airborne, these findings suggest that Acanthamoeba is a potential vector in the transmission of A. hydrophila and E. aerogenes to susceptible hosts.
Collapse
|
32
|
Utility of insects for studying human pathogens and evaluating new antimicrobial agents. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 135:1-25. [PMID: 23604210 DOI: 10.1007/10_2013_194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Insect models, such as Galleria mellonella and Drosophila melanogaster have significant ethical, logistical, and economic advantages over mammalian models for the studies of infectious diseases. Using these models, various pathogenic microbes have been studied and many novel virulence genes have been identified. Notably, because insects are susceptible to a wide variety of human pathogens and have immune responses similar to those of mammals, they offer the opportunity to understand innate immune responses against human pathogens better. It is important to note that insect pathosystems have also offered a simple strategy to evaluate the efficacy and toxicity of many antimicrobial agents. Overall, insect models provide a rapid, inexpensive, and reliable way as complementary hosts to conventional vertebrate animal models to study pathogenesis and antimicrobial agents.
Collapse
|
33
|
Bui XT, Qvortrup K, Wolff A, Bang DD, Creuzenet C. Effect of environmental stress factors on the uptake and survival of Campylobacter jejuni in Acanthamoeba castellanii. BMC Microbiol 2012; 12:232. [PMID: 23051891 PMCID: PMC3538707 DOI: 10.1186/1471-2180-12-232] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 10/03/2012] [Indexed: 11/22/2022] Open
Abstract
Background Campylobacter jejuni is a major cause of bacterial food-borne illness in Europe and North America. The mechanisms allowing survival in the environment and transmission to new hosts are not well understood. Environmental free-living protozoa may facilitate both processes. Pre-exposure to heat, starvation, oxidative or osmotic stresses encountered in the environment may affect the subsequent interaction of C. jejuni with free-living protozoa. To test this hypothesis, we examined the impact of environmental stress on expression of virulence-associated genes (ciaB, dnaJ, and htrA) of C. jejuni and on its uptake by and intracellular survival within Acanthamoeba castellanii. Results Heat, starvation and osmotic stress reduced the survival of C. jejuni significantly, whereas oxidative stress had no effect. Quantitative RT-PCR experiments showed that the transcription of virulence genes was slightly up-regulated under heat and oxidative stresses but down-regulated under starvation and osmotic stresses, the htrA gene showing the largest down-regulation in response to osmotic stress. Pre-exposure of bacteria to low nutrient or osmotic stress reduced bacterial uptake by amoeba, but no effect of heat or oxidative stress was observed. Finally, C. jejuni rapidly lost viability within amoeba cells and pre-exposure to oxidative stress had no significant effect on intracellular survival. However, the numbers of intracellular bacteria recovered 5 h post-gentamicin treatment were lower with starved, heat treated or osmotically stressed bacteria than with control bacteria. Also, while ~1.5 × 103 colony forming unit/ml internalized bacteria could typically be recovered 24 h post-gentamicin treatment with control bacteria, no starved, heat treated or osmotically stressed bacteria could be recovered at this time point. Overall, pre-exposure of C. jejuni to environmental stresses did not promote intracellular survival in A. castellanii. Conclusions Together, these findings suggest that the stress response in C. jejuni and its interaction with A. castellanii are complex and multifactorial, but that pre-exposure to various stresses does not prime C. jejuni for survival within A. castellanii.
Collapse
Affiliation(s)
- Xuan Thanh Bui
- National Veterinary Institute, Technical University of Denmark, Aarhus NDK-8200, Denmark
| | | | | | | | | |
Collapse
|