Environmental factors on virulence of Aeromonas hydrophila

Abreu, Ruan Emmanuell Franco de; Magalhães, Thaís Correia; Souza, Renilde Cordeiro de; Oliveira, Samira Teixeira Leal de; Ibelli, A. M. G.; Demarqui, Fábio N.; Gouveia, João Js; Costa, Mateus Matiuzzi da; Gouveia, Gisele Veneroni

doi:10.1007/s10499-017-0230-2

Cited by 18 publications

(15 citation statements)

References 37 publications

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“…Aeromonas salmonicida , the only non‐motile species within the genus Aeromonas and the causative agent for furunculosis in salmonids, is an obligate fish pathogen. Almost all motile aeromonads might also act as opportunistic pathogens for fish and can cause abdominal oedema, dermatitis, deep ulcers, exophthalmos and septicaemia, especially in stressed and immunosuppressed fish (Abreu et al., ; Buller, ; Janda & Abbott, ).…”

Section: Introductionmentioning

confidence: 99%

Diagnostic methods for identifying different Aeromonas species and examining their pathogenicity factors, their correlation to cytotoxicity and adherence to fish mucus

Jung‐Schroers

Jung

Ryll

et al. 2018

Journal of Fish Diseases

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Aeromonas spp. are ubiquitous in the aquatic environment, acting as facultative or obligate pathogens for fish. Identifying Aeromonas spp. is important for pathogenesis and prognosis in diagnostic cases but can be difficult because of their close relationship. Forty‐four already characterized isolates of Aeromonas spp. were analysed by 16S rRNA gene sequencing, by gyrase B sequencing, by analysing their fatty acid profiles, by biochemical reactions and by MALDI‐TOF MS. To determine their pathogenicity, cytotoxicity, adhesion to mucus and the expression of 12 virulence factors were tested. The susceptibility of the isolates towards 13 different antibiotics was determined. MALDI‐TOF MS was found to be an acceptable identification method for Aeromonas spp. Although the method does not detect all species correctly, it is time‐effective and entails relatively low costs and no other methods achieved better results. A high prevalence of virulence‐related gene fragments was detected in almost all examined Aeromonas spp., especially in A. hydrophila and A. salmonicida, and most isolates exhibited a cytotoxic effect. Single isolates of A. hydrophila and A. salmonicida showed multiple resistance to antibiotics. These results might indicate the potentially pathogenic capacity of Aeromonas spp., suggesting a risk for aquatic animals and even humans, given their ubiquitous nature.

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Section: Introductionmentioning

confidence: 99%

Diagnostic methods for identifying different Aeromonas species and examining their pathogenicity factors, their correlation to cytotoxicity and adherence to fish mucus

Jung‐Schroers

Jung

Ryll

et al. 2018

Journal of Fish Diseases

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“…In this study, the effect of salinity and pH on the production of extracellular virulence factors by Aeromonas , which was isolated from different food sources, was analyzed. Although it is well documented that environmental factors can influence bacterial growth, the relationship between environmental variables and intrinsic bacterial capabilities are not clearly elucidated (Abreu et al., ). It has been reported that the range of environmental parameters affecting the bacterial virulence factor production is significantly lower than the range that affects bacterial growth (Cheng & Chen, ).…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that some environmental factors, such as pH, salinity, and temperature, can control the growth of Aeromonas (Abreu et al, 2018;Delamare, Costa, Silveira, & Echeverrigaray, 2002). In food-processing environments, these factors play a crucial role in food preservation.…”

Section: Introductionmentioning

confidence: 99%

Effect of pH and Salinity on the Production of Extracellular Virulence Factors by Aeromonas from Food Sources

John

Vidyalakshmi

Hatha

2019

Journal of Food Science

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The ability to produce various extracellular enzymes is considered as an important virulence feature in Aeromonas spp., in addition to producing specific virulence factors such as aerolysin and hemolysin. In this study, the effect of salinity and pH on the production of extracellular virulence factors by Aeromonas was investigated. Aeromonas was obtained from different food sources. A comparative study of the activities of extracellular enzymes secreted by these bacteria at different environmental conditions can widen our understanding on their pathogenicity. The activities of various extracellular enzymes such as amylase, gelatinase, and caseinase, which are implicated as virulence factors, were measured in vitro by calculating the enzymatic activity index (EAI) of each enzyme using standard laboratory protocols. For all enzymes, a significant change (P < 0.05) in the EAI was observed when the concentration of NaCl in the media increased from 0.5% to 3%. Among three enzymes tested, caseinase was found to be affected the most by salinity, with a significant difference in EAI when NaCl concentration in the media increased from 0.5% to 2%. Similarly, amylase was found to be affected the most by acidity. The pH values ranging from 6 to 9 did not exert any significant change in EAI of amylase; however, a pH value of 5 had a significant effect. Overall, compared to salinity, the change in pH was found to be less effective in controlling the extracellular virulence factor production in Aeromonas. Practical Applications The practical application is to minimize the extracellular virulence factor production by Aeromonas in food commodities by altering the salt content and pH. The results demonstrate that an increase in salinity and a decrease in pH can minimize the extracellular virulence factor production by Aeromonas spp.

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“…Abreu et al. (2018) demonstrated that an increase in ammonia concentration consequently upregulated mRNA transcription of fla gene that is involved in the formation of polar flagellum which is an important virulence factor for A. hydrophila motility, adhesion and biofilm formation (Janda & Abbott, 2010). Taken together, the present data generated over a period 120 days clearly show that routine monitoring of physicochemical water parameters of the tilapia's culture environment such as pH, temperature, DO and un‐ionized ammonia concentration is a critical component of good tilapia aquaculture management that may practically control if not eradicate losses associated with bacterial diseases (Al‐Harbi & Uddin, 2003, 2004, 2005; Pakingking et al., 2015).…”

Section: Discussionmentioning

confidence: 99%

“…This intervention effectively regulated the ammonia levels to be within the range of can utilize ammonia as a growth factor thus allowing them to express essential factors involved in the production of basic virulence mechanisms such as motility and adhesion processes that are key elements for bacterial pathogenesis (Janda & Abbott, 2010;Rael & Frankenberger, 1996). Abreu et al (2018) & Uddin, 2003& Uddin, , 2004& Uddin, , 2005Pakingking et al, 2015).…”

Section: Taxonomic Composition Of Aeromonas Speciesmentioning

confidence: 99%

Aeromonasload and species composition in tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines

2020

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Aeromonas load and species composition in the rearing water, sediment, gills and intestines of healthy tilapia Oreochromis niloticus collected every 2 weeks from Days 30 to 120 after stocking in six earthen ponds in the Philippines were determined. Presumptive Aeromonas counts (PACs) in the water and sediment ranged from 10 1-10 3 c.f.u./ml and 10 1-10 3 c.f.u./g while in the gills and intestines, PACs ranged from 10 4-10 7 c.f.u./g and 10 2-10 5 c.f.u./g, respectively. Presumptive Aeromonas counts in the water, sediment, and gills of tilapia varied among days of culture while in the intestines of tilapia, PACs markedly dropped by approximately 2 logs at Day 75 and either remained in the same level or decreased by another 1 log at Day 120 of growout culture. Aeromonas hydrophila predominantly constituted 94% of all presumptive Aeromonas spp. examined (n = 343), followed by A. sobria (4%) and A. salmonicida (2%). Taken together, current data provide some putative threshold levels of tilapia reared in earthen ponds to Aeromonas spp. The dominance of A. hydrophila together with negligible population of A. salmonicida and A. sobria indicate that Aeromonas are common commensal bacteria in tilapia and their environment which under conditions of stress could instigate disease epizootics.

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Environmental factors on virulence of Aeromonas hydrophila

Cited by 18 publications

References 37 publications

Diagnostic methods for identifying different Aeromonas species and examining their pathogenicity factors, their correlation to cytotoxicity and adherence to fish mucus

Diagnostic methods for identifying different Aeromonas species and examining their pathogenicity factors, their correlation to cytotoxicity and adherence to fish mucus

Effect of pH and Salinity on the Production of Extracellular Virulence Factors by Aeromonas from Food Sources

Aeromonasload and species composition in tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines

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