Characterization of cytotoxic, hemolytic Aeromonas caviae clinical isolates and their identification by determining presence of a unique hemolysin gene

Wang, G; Tyler, Kevin; Munro, C.; Johnson, Wendy M.

doi:10.1128/jcm.34.12.3203-3205.1996

Cited by 43 publications

(19 citation statements)

References 18 publications

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“…Many studies have suggested that as compared to A. hydrophila or A. sobria , A. caviae strains isolated from various sources are rarely able to produce virulence factors [1, 2, 4, 20, 22]. In contrast, other reports have noted that most isolates of A. caviae were able to produce several potential virulence factors [29–33]. However, as suggested by Namdari and Bottone [34, 35], the heterogeneity in the findings mentioned above, may be explained to some extent by several parameters including the incubation time of cultures, culture medium used and more importantly, the repressed toxin production due to the presence of glucose in the growth medium.…”

Section: Discussionmentioning

confidence: 95%

“…According to these results, a high number of strains which possessed a battery of putative extracellular virulence traits, were prevalent mainly in highly polluted sources (stabilisation pond effluents and raw sewage) while only a few of the A. caviae isolated from low‐ or non‐polluted aquatic environments produced virulence factors. Earlier studies have suggested that A. caviae was the most frequently isolated species in human faecal samples [7–9, 31, 32]. The clinical isolates are furthermore more often described as more virulent than environmental isolates [33–36].…”

Section: Discussionmentioning

confidence: 99%

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Characterisation of potential virulence markers in Aeromonas caviae isolated from polluted and unpolluted aquatic environments in Morocco

Imziln

Krovacek

Baloda³

et al. 1998

FEMS Microbiology Ecology

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A total of 100 Aeromonas caviae strains isolated from river waters (38 isolates), raw sewage (30 isolates) and effluents of stabilisation ponds (i.e. treated sewage; 32 isolates) in Marrakech, Morocco, were tested for the presence of putative virulence factors to delineate differences, if any, in their enteropathogenic potential in relation to the source of isolation. A number of A. caviae isolates were able to elaborate at least one of the tested virulence factors. Of the 100 strains tested, 27 were capable of producing haemolysins, 19 produced cytotoxin, 24 produced cytotonic toxin, while 18 of the isolates possessed the capacity to adhere to HenLe 407 human intestinal cells with more than five bacteria adhering per cell. In order to assess the virulence potential of A. caviae isolates in relation to the source of isolation, we suggest the potential virulence index (PVI) as a tool for comparison. It is calculated as PVI=x/ny, where x is the number of positive occurrence of virulence factors in a population y, and n is the number of suitable virulence factors used for the calculation of the PVI. Accordingly, in this study A. caviae strains isolated from treated sewage samples showed a higher PVI (=0.406) than those isolated from raw sewage (PVI=0.175) or those from river waters (PVI=0.09). These results suggest that stabilisation pond systems used for sewage purification under arid climate conditions in Marrakech, may have selected potentially enteropathogenic A. caviae strains.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Characterisation of potential virulence markers in Aeromonas caviae isolated from polluted and unpolluted aquatic environments in Morocco

Imziln

Krovacek

Baloda³

et al. 1998

FEMS Microbiology Ecology

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“…AERO, ACH, and ASH3 in Fig. 4C are hemolysins produced by A. hydrophila (16), A. caviae (30), and A. salmonicida (12), respectively. The sequences of these hemolysins are homologous with our hemolysin.…”

Section: Cloning and Nucleotide Sequence Analysis Of The Hemolysin Genementioning

confidence: 99%

“…(C) The amino acid sequence deduced from the above sequence is shown on line 357. The sequences of ASAl, ASAER, AERO, ACH and ASH3 are from(13),(17),(16),(30) and(12), respectively.…”

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confidence: 99%

Purification and Characterization of Enterotoxin Produced by Aeromonas sobria

Fujii

Nomura

Kanzawa

et al. 1998

Microbiology and Immunology

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We purified the toxin of Aeromonas sobria capable of inducing a positive response in the mouse intestinal loop assay. The purified toxin showed a positive response not only in the loop assay but also in a hemolytic assay. Subsequently, we cloned the toxin gene and demonstrated that the product of this gene possessed both hemolytic and enterotoxic activities. These results showed that the enterotoxin of A. sobria possesses hemolytic activity. Nucleotide sequence determination of the toxin gene and amino acid sequence analysis of the purified toxin revealed that it is synthesized as a precursor composed of 488 amino acid residues, and that the 24 amino-terminal amino acid residues of the precursor is removed in the mature toxin. As antiserum against the purified toxin neutralized the fluid accumulation induced by living cells not only of A. sobria but also of A. hydrophila, this and antigenically related toxin(s) are thought to play an essential role in the induction of diarrhea by these organisms. The toxin-injured Chinese hamster ovary (CHO) cells induced the release of intracellular lactose dehydrogenase (LDH). The release of LDH from CHO cells and the lysis of erythrocytes by the toxin were repressed by the addition of dextran to the reaction solution, indicating that the toxin forms pores in the membranes and that the cells were injured by the osmotic gradient developed due to pore formation. However, the histopathological examination of intestinal cells exposed to the toxin showed that it caused fluid accumulation in the mouse intestinal loop without causing cellular damage.

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“…Moreover, a number of PCR assays have been developed for the direct detection of A. caviae. Wang et al (1996) developed a PCR assay targeting the hemolysin gene, and their results revealed that the primers were specific to hemolytic A. caviae. Identification of A. caviae via the 16S rRNA gene has been reported, but those primers could not discriminate between closely related species such as A. jandaei (Nayduch et al 2001) and A. trota (Khan and Cerniglia 1997); therefore, an additional step is needed for identification at the species level, such as sequencing and restriction enzyme digestion.…”

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Development of a PCR Assay Based on a Single–Base Pair Substitution for the Detection of Aeromonas caviae by Targeting the gyrB Gene

et al. 2015

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Aeromonas caviae is a bacterial pathogen that causes various infectious diseases in both humans and animals. To facilitate its detection, we developed species-specific primer sets targeting polymorphisms in the gyrB gene for use in a PCR assay. The technique was able to detect 100% (29/29) of the A. caviae strains tested using either of two sets of primers (designated ACF1-ACR and ACF3-ACR), which produced 293-bp and 206-bp amplicons, respectively. Another set of primers (designated ACF2-ACR) yielded a 237-bp amplicon and exhibited 90% (26/29) positive results with respect to A. caviae. None of the primer sets exhibited cross-reactivity with 12 non-A. caviae isolates and 52 other non-Aeromonas bacteria. The detection limit using the ACF2-ACR and ACF3-ACR primer sets in pure culture was 1.6 × 10(3) CFU/mL, or 6 CFU per reaction, whereas that of the ACF1-ACR primer set was 1.6 × 10(4) CFU/mL, or 60 CFU per reaction. In the case of spiked Nile Tilapia Oreochromis niloticus, the sensitivity of all primer sets without enrichment was 1.8 × 10(4) CFU/g, or 30 CFU per reaction. Primer set ACF3-ACR was the best for a PCR assay targeting the gyrB gene, and the PCR technique developed was rapid, specific, and sensitive for the identification of A. caviae.

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Characterization of cytotoxic, hemolytic Aeromonas caviae clinical isolates and their identification by determining presence of a unique hemolysin gene

Cited by 43 publications

References 18 publications

Characterisation of potential virulence markers in Aeromonas caviae isolated from polluted and unpolluted aquatic environments in Morocco

Characterisation of potential virulence markers in Aeromonas caviae isolated from polluted and unpolluted aquatic environments in Morocco

Purification and Characterization of Enterotoxin Produced by Aeromonas sobria

Development of a PCR Assay Based on a Single–Base Pair Substitution for the Detection of Aeromonas caviae by Targeting the gyrB Gene

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