Passage through
            <i>Tetrahymena tropicalis</i>
            Triggers a Rapid Morphological Differentiation in
            <i>Legionella pneumophila</i>

Faulkner, Gary; Berk, Sharon G.; Garduño, Elizabeth; Ortiz-Jiménez, Marco A.; Garduño, Rafael A.

doi:10.1128/jb.00751-08

Cited by 50 publications

(73 citation statements)

References 41 publications

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“…A hallmark virulence trait of L. pneumophila is the ability to differentiate between morphologically and phenotypically distinct states within host cells, including replicative and transmissive cell types (32,134). In some protozoan hosts, transmissive L. pneumophila differentiates further into "mature intracellular forms" suited for environmental persistence (66).…”

Section: Legionella Pneumophilamentioning

confidence: 99%

ppGpp Conjures Bacterial Virulence

Dalebroux

Svensson

Gaynor

et al. 2010

Microbiol Mol Biol Rev

333

364

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SUMMARY Like for all microbes, the goal of every pathogen is to survive and replicate. However, to overcome the formidable defenses of their hosts, pathogens are also endowed with traits commonly associated with virulence, such as surface attachment, cell or tissue invasion, and transmission. Numerous pathogens couple their specific virulence pathways with more general adaptations, like stress resistance, by integrating dedicated regulators with global signaling networks. In particular, many of nature's most dreaded bacteria rely on nucleotide alarmones to cue metabolic disturbances and coordinate survival and virulence programs. Here we discuss how components of the stringent response contribute to the virulence of a wide variety of pathogenic bacteria.

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Section: Legionella Pneumophilamentioning

confidence: 99%

ppGpp Conjures Bacterial Virulence

Dalebroux

Svensson

Gaynor

et al. 2010

Microbiol Mol Biol Rev

333

364

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“…was grown for 5 days at 25°C. The protozoan cultures were centrifuged [T. pyriformis at 840 g for 10 min (Faulkner et al, 2008); A. castellanii and Cercomonas sp. at 540 g for 10 min (Vaerewijck et al, 2012)] and the supernatant was removed.…”

Section: Cultivation Of Flpmentioning

confidence: 99%

Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety

Chavatte

Baré

Lambrecht

et al. 2014

International Journal of Food Microbiology

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In the present study, the occurrence of free-living protozoa (FLP) and foodborne bacterial pathogens on dishcloths was investigated. Dishcloths form a potentially important source of cross-contamination with FLP and foodborne pathogens in food-related environments. First various protocols for recovering and quantifying FLP from dishcloths were assessed. The stomacher technique is recommended to recover flagellates and amoebae from dishcloths. Ciliates, however, were more efficiently recovered using centrifugation. For enumeration of freeliving protozoa on dishcloths, the Most Probable Number method is a convenient method. Enrichment was used to assess FLP diversity on dishcloths (n = 38). FLP were found on 89% of the examined dishcloths; 100% of these tested positive for amoebae, 71% for flagellates and 47% for ciliates. Diversity was dominated by amoebae: vahlkampfiids, vannellids, Acanthamoeba spp., Hyperamoeba sp. and Vermamoeba vermiformis were most common. The ciliate genus Colpoda was especially abundant on dishcloths while heterotrophic nanoflagellates mainly belonged to the genus Bodo, the glissomonads and cercomonads. The total number of FLP in used dishcloths ranged from 10 to 10 4 MPN/cm 2 . Flagellates were the most abundant group, and ciliates the least abundant. Detergent use was identified as a prime determinant of FLP concentrations on used dishcloths. Bacterial load on dishcloths was high, with a mean total of aerobic bacteria of 7.47 log 10 cfu/cm 2 . Escherichia coli was detected in 68% (26/38) of the used dishcloths, with concentrations up to 4 log 10 cfu/cm 2 . Foodborne pathogens including Staphylococcus aureus (19/38), Arcobacter butzleri (5/38) and Salmonella enterica subsp. enterica ser. Halle (1/38) were also present. This study showed for the first time that FLP, including some opportunistic pathogens, are a common and diverse group on dishcloths. Moreover, important foodborne pathogens are also regularly recovered. This simultaneous occurrence makes dishcloths a potential risk factor for cross-contamination and a microbial niche for bacteria-FLP interactions.

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“…The C. jejuni packaged in expelled free MLBs was a little bigger than that in the intracellular vacuoles; the bacteria are mostly rod-shaped, and their size may exceed 2 m, with an average length of 1 m. Here, this phenomenon is probably due to the loosening of MLB membranes after expulsion into the medium, resulting from decreased pressure on the MLBs, compared with that inside the protozoal cell (54). Transmission electron micrographs of E. coli and L. pneumophila contained in MLBs also showed that the bacteria inside food vacuoles of Tetrahymena were smaller than those inside expelled MLBs (47,54).…”

Section: Discussionmentioning

confidence: 99%

Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis

Trigui

Paquet

Charette

et al. 2016

Appl Environ Microbiol

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dCampylobacter jejuni is 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. jejuni in 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. jejuni up 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. jejuni in the environment and its possible transmission between different reservoirs in food and potable water through packaging. Campylobacter jejuni is a leading cause of human gastroenteritis worldwide and a major public health problem (1-3). Severe symptoms of C. jejuni infection include high fever, watery to bloody diarrhea, nausea, and vomiting (4). In severe cases, C. jejuni is associated with serious postinfectious complications, such as Guillain-Barré syndrome (5, 6).Despite causing a serious disease in humans, C. jejuni is usually viewed as commensal in chickens (7) and livestock animals such as cattle (8) and pigs (9). Once these animals are colonized with Campylobacter spp., they excrete large numbers of the microorganisms in their feces and commonly contaminate different aquatic habitats, such as surface waters close to farming activities, agricultural runoff, wastewater effluent, sewage, and marine environments (10). Numerous epidemiological studies have demonstrated that water is not only a significant reservoir of C. jejuni but also an important factor for the spread of C. jejuni in farms, throughout flocks, and in slaughterhouses (11-15).C. jejuni requires a microaerobic environment (80% N 2 , 10% CO 2 , 5% H 2 , and 5% O 2 ) (16) and a narrow range of temperatures (37 to 43°C) for optimal growth (17). Because of the constraints imposed by its sensitivity to oxygen, C. jejuni is considered less able to tolerate environmental stress than other foodborne pathogens (18). Once outside the host, however, the interaction of C. jejuni with other microorganisms could help it survive high concentrations of oxygen and other environmental stresses.Since the study by Snelling et al. (19), in which Campylobacter and protozoa were isolated from the same broiler drinking water systems, the potential interactions between these microorganisms have been investigate...

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Passage through Tetrahymena tropicalis Triggers a Rapid Morphological Differentiation in Legionella pneumophila

Cited by 50 publications

References 41 publications

ppGpp Conjures Bacterial Virulence

ppGpp Conjures Bacterial Virulence

Co-occurrence of free-living protozoa and foodborne pathogens on dishcloths: Implications for food safety

Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis

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