Publicação
Prevalence and characterization of Aeromonas spp. in an ex situ program for threatened freshwater fish : consequences for conservation and public health
| Resumo: | ABSTRACT - Prevalence and characterization of Aeromonas spp. in an ex situ program for threatened freshwater fish : consequences for conservation and public health - Ex situ reproduction programs are essential conservation techniques for endangered species, though their success faces many limitations, namely the possibility of disease development and dissemination of virulent and antimicrobial resistant bacteria in captivity. In this study, an ex situ assay focusing on Portuguese arched-mouth nase (Iberochondrostoma lusitanicum) — a critically endangered leuciscid species occurring only in small drainages of Portugal — was performed to investigate the effect of simple biosafety measures (i.e., material disinfection protocols and animal handling with gloves) on the population structure, virulence factors’ expression and antimicrobial resistance profiles of a potential pathogenic and zoonotic genus, Aeromonas. Our findings show that technicians were colonized by Aeromonas spp. after handling the animals and suggest that the use of protective measures may have led to a decline in Aeromonas spp. prevalence. Furthermore, bacterial isolates displayed significantly lower virulence index values when virulence phenotypical expression was tested at 22ºC — with a noteworthy decrease of gelatinolytic activity, proteolytic activity, and slime production in isolates from the experimental model where protective measures were employed. Moreover, antimicrobial resistant profiles in Aeromonas spp. significantly increased in isolates collected in the first to the final week of the study, with all isolates collected at the end of the assay being classified as multidrug-resistant. These results sustain the growing concern for public health regarding zoonotic transmission of pathogens and antimicrobial resistance dissemination, namely in Aeromonas spp., in aquatic ex situ programs, and further research on prevention measures is needed. Despite this study not having fully validated a definitive link between the biosafety practices used and the noted shifts in bacterial dynamics and virulence expression, these measures are simple and low-cost tools that could easily be applied in ex situ breeding programs for aquatic animals worldwide. |
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| Autores principais: | Ferreira, Guadalupe Amaro |
| Assunto: | Ex situ Antimicrobial resistance Virulence Aeromonas spp. Iberochondrostoma lusitanicum Ex situ Resistência antimicrobiana Virulência Aeromonas spp. Iberochondrostoma lusitanicum |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | ABSTRACT - Prevalence and characterization of Aeromonas spp. in an ex situ program for threatened freshwater fish : consequences for conservation and public health - Ex situ reproduction programs are essential conservation techniques for endangered species, though their success faces many limitations, namely the possibility of disease development and dissemination of virulent and antimicrobial resistant bacteria in captivity. In this study, an ex situ assay focusing on Portuguese arched-mouth nase (Iberochondrostoma lusitanicum) — a critically endangered leuciscid species occurring only in small drainages of Portugal — was performed to investigate the effect of simple biosafety measures (i.e., material disinfection protocols and animal handling with gloves) on the population structure, virulence factors’ expression and antimicrobial resistance profiles of a potential pathogenic and zoonotic genus, Aeromonas. Our findings show that technicians were colonized by Aeromonas spp. after handling the animals and suggest that the use of protective measures may have led to a decline in Aeromonas spp. prevalence. Furthermore, bacterial isolates displayed significantly lower virulence index values when virulence phenotypical expression was tested at 22ºC — with a noteworthy decrease of gelatinolytic activity, proteolytic activity, and slime production in isolates from the experimental model where protective measures were employed. Moreover, antimicrobial resistant profiles in Aeromonas spp. significantly increased in isolates collected in the first to the final week of the study, with all isolates collected at the end of the assay being classified as multidrug-resistant. These results sustain the growing concern for public health regarding zoonotic transmission of pathogens and antimicrobial resistance dissemination, namely in Aeromonas spp., in aquatic ex situ programs, and further research on prevention measures is needed. Despite this study not having fully validated a definitive link between the biosafety practices used and the noted shifts in bacterial dynamics and virulence expression, these measures are simple and low-cost tools that could easily be applied in ex situ breeding programs for aquatic animals worldwide. |
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