Survival of Vibrio cholerae Inside Acanthamoeba and Detection of Both Microorganisms From Natural Water Samples May Point out the Amoeba as a Protozoal Host for V. cholerae

Abd, Hadi

doi:10.4172/2155-9597.s1-003

Cited by 9 publications

(13 citation statements)

References 80 publications

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“…FLA are potential environmental reservoirs of several important pathogens of the human intestinal tract, including Salmonella spp., Shigella spp., Campylobacter spp., and enterohemorrhagic Escherichia coli (2-5). Specifically, due to the large infective dose of Vibrio cholerae (10 8 to 10 9 cells), it has been suggested that Acanthamoebae may act as both environmental hosts and intracellular multipliers of this organism, allowing it to grow sufficiently to be able to cause human infection (6).…”

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confidence: 99%

Free-Living Amoebae Recovered from Human Stool Samples in Strongyloides Agar Culture

Bradbury

2014

J Clin Microbiol

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Our laboratory in The Gambia, West Africa, performs Koga agar (1.5% bacteriological agar, 0.5% sodium chloride, 0.5% meat extract, 0.1% bacteriological peptone) culture for larvae of strongyle nematodes on human fecal samples for which parasitological investigation has been requested. We have recovered freeliving amoebae (FLA) from human fecal specimens on two occasions over a period of 9 months (representing 130 individual fecal cultures) on this agar (Fig. 1). The amoebae in both cases were identified as Hartmannella species based upon the morphology of trophozoites and cysts in agar culture ( Fig. 2) and their inability to enflagellate in distilled water after 8 h of incubation at 37°C. No other types of FLA have been recovered. Due to resource constraints, sequencing of the partial 18S rRNA gene and internal transcribed spacer (ITS) region could not be performed, and this identification must remain presumptive. Specimens were collected into sterile containers, and Koga culture plates were sterile and sealed with Parafilm prior to incubation at 30°C for 5 days; therefore, environmental contamination with FLA was very unlikely. Repeat specimens could not be obtained from subjects, and so it was not possible to determine if these findings represent transient passage of FLA or true intestinal colonization.It has been postulated that FLA provide a vehicle for bacterial pathogens to gain entry into the human respiratory tract (1). The possibility that free-living amoeba may have a similar role in the introduction of bacterial pathogens into the human intestinal tract (and particularly in defense against stomach acid during transit to the duodenum) should be further considered, given these findings. FLA are potential environmental reservoirs of several important pathogens of the human intestinal tract, including Salmonella spp., Shigella spp., Campylobacter spp., and enterohemorrhagic Escherichia coli (2-5). Specifically, due to the large infective dose of Vibrio cholerae (10 8 to 10 9 cells), it has been suggested that Acanthamoebae may act as both environmental hosts and intracellular multipliers of this organism, allowing it to grow sufficiently to be able to cause human infection (6).Human respiratory tract (7, 8) and urinary tract (9) colonization with Acanthamoeba spp. may occur. Recovery of FLA, including Hartmannella spp. from the intestinal tracts of rodents (10), reptiles (11), and fish and birds (12), has been previously reported. Only one previous reference in the literature describes the recovery of FLA from the human intestinal tract (13).The potential for transient passage or true colonization of the

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confidence: 99%

Free-Living Amoebae Recovered from Human Stool Samples in Strongyloides Agar Culture

Bradbury

2014

J Clin Microbiol

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“…Indeed, EHEC and V. cholerae share similarities being waterborne and causing diarrhoeal disease and generally are considered to be extracellular pathogens. Furthermore, like V. cholerae the EHEC in relation to A. castellanii apparently establish a controlled relationship with the amoebae and behaved as a facultative intracellular bacterium (Abd et al ., ; Valeru et al ., ). However, unlike EHEC, the presence of V. cholerae promoted the growth of amoebae and also enhanced growth, viability and survival of the bacteria (Abd et al ., ; Chekabab et al ., ).…”

Section: Discussionmentioning

confidence: 98%

“…Furthermore, like V. cholerae the EHEC in relation to A. castellanii apparently establish a controlled relationship with the amoebae and behaved as a facultative intracellular bacterium (Abd et al ., ; Valeru et al ., ). However, unlike EHEC, the presence of V. cholerae promoted the growth of amoebae and also enhanced growth, viability and survival of the bacteria (Abd et al ., ; Chekabab et al ., ). In co‐culture experiments, S. Typhi was not cytotoxic to A. castellanii , and bacteria surviving in co‐culture were extracellular and did not require contact with amoebae for their survival (Douesnard‐Malo & Daigle, ).…”

Section: Discussionmentioning

confidence: 98%

Shiga toxins decrease enterohaemorrhagicEscherichia colisurvival withinAcanthamoeba castellanii

Chekabab

Charette

Dozois

et al. 2013

FEMS Microbiol Lett

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Enterohaemorrhagic Escherichia coli (EHEC) are zoonotic pathogens transmitted to humans through contaminated water or bovine products. One of the strategies used by pathogenic bacteria to survive in aquatic environments is using free-living amoebae as hosts. Acanthamoeba castellanii is an amoeba known to host several waterborne pathogens. This study investigates the survival of EHEC with A. castellanii, which could contribute to its spread and transmission to humans. We used a gentamicin protection assay as well as fluorescence and electron microscopy to monitor the intra-amoebae survival of EHEC O157:H7 over 24 h. The results showed that EHEC were able to survive within A. castellanii and that this survival was reduced by Shiga toxins (Stx) produced by EHEC. A toxic effect mediated by Stx was demonstrated by amoebae mortality and LDH release during co-culture of EHEC and amoeba. This work describes the ability of EHEC to survive within A. castellanii, and this host-pathogen interaction is partially controlled by the Stx. Thus, this ubiquitous amoeba could represent an environmental niche for EHEC survival and transmission.

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“…Sea living animals may carry the vibrio, and the combination of increased water temperature and salinity may contribute to increased association rates of the bacteria with sea-living animals or protozoa ( 11 ). The ability of FLA to act as reservoirs for many bacteria has been studied (reviewed in ( 12 )). However, output of the interaction between bacteria and amoeba is dependent on whether the interacting bacterium is extracellular or intracellular and on whether it possesses a type three secretion system (TTSS), since TTSS effector proteins are observed to strongly affect output of the interaction ( 12 ).…”

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confidence: 99%

“…However, output of the interaction between bacteria and amoeba is dependent on whether the interacting bacterium is extracellular or intracellular and on whether it possesses a type three secretion system (TTSS), since TTSS effector proteins are observed to strongly affect output of the interaction ( 12 ). The amoeba may become a host or predator to the interacted bacteria but, on the other hand, many bacterial species are able to kill the amoeba ( 12 ). V. cholerae O1, V. cholerae O139, and V. mimicus have been found to be able to grow inside A. castellanii ( 13 – 15 ).…”

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confidence: 99%

Swedish isolates of Vibrio cholerae enhance their survival when interacted intracellularly with Acanthamoeba castellanii

Shanan

Bayoumi

Saeed

et al. 2016

Infection Ecology & Epidemiology

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Vibrio cholerae is a Gram-negative bacterium that occurs naturally in aquatic environment. Only V. cholerae O1 and V. cholerae O139 produce cholera toxin and cause cholera, other serogroups can cause gastroenteritis, open wounds infection, and septicaemia. V. cholerae O1 and V. cholerae O139 grow and survive inside Acanthamoeba castellanii. The aim of this study is to investigate the interactions of the Swedish clinical isolates V. cholerae O3, V. cholerae O4, V. cholerae O5, V. cholerae O11, and V. cholerae O160 with A. castellanii. The interaction between A. castellanii and V. cholerae strains was studied by means of amoeba cell counts, viable counts of the bacteria in the absence or presence of amoebae, and of the intracellularly growing bacteria, visualised by electron microscopy. These results show that all V. cholerae can grow and survive outside and inside the amoebae, disclosing that V. cholerae O3, V. cholerae O4, V. cholerae O5, V. cholerae O11, and V. cholerae O160 all can be considered as facultative intracellular bacteria.

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Survival of Vibrio cholerae Inside Acanthamoeba and Detection of Both Microorganisms From Natural Water Samples May Point out the Amoeba as a Protozoal Host for V. cholerae

Cited by 9 publications

References 80 publications

Free-Living Amoebae Recovered from Human Stool Samples in Strongyloides Agar Culture

Free-Living Amoebae Recovered from Human Stool Samples in Strongyloides Agar Culture

Shiga toxins decrease enterohaemorrhagicEscherichia colisurvival withinAcanthamoeba castellanii

Swedish isolates of Vibrio cholerae enhance their survival when interacted intracellularly with Acanthamoeba castellanii

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