Microbiology, Aquatic Science, Applied Microbiology and Biotechnology
12
Scopus Publications
Scopus Publications
Flavobacterium oreochromis From Farmed Tambaqui (Colossoma macropomum): Insights Into Genetic, Phenotypic and Pathogenic Diversity Elcimara Cardoso Pereira, Mariluce dos Reis Ferreira, Suzana Kotzent, Luiz Fagner Ferreira Nogueira, Guilherme Campos Tavares, Henrique César Pereira Figueiredo, Fabiana Pilarski, Gustavo Moraes Ramos Valladão, Sílvia Umeda Gallani Journal of Fish Diseases, 2026 Flavobacterium spp. are the etiological agents of columnaris disease. Although there is evidence that columnaris poses a significant threat to the farming of tambaqui ( Colossoma macropomum ), there remains a large gap in understanding the genetic and phenotypic diversities of columnaris‐causing bacteria (CCB). This study was designed to identify diversity traits of CCB from tambaqui reared in Brazil. From 26 CCB outbreaks previously identified as F. columnare with MALDI‐TOF were prospected. A multiplex PCR was conducted to confirm the bacterial species, while REP‐PCR was used to determine the differences in genetic patterns (GP), and putative virulence genes were accessed using PCR ( norB , trx and gtf ). All isolates were identified as F. oreochromis by multiplex PCR. REP‐PCR identified 4 genetic variants (GP 1 , GP 2 , GP 3 and GP 4 ), with GP 3 being the most frequent. All the putative virulence genes were detected in all analysed strains. One strain representing each GP was subjected to the description of phenotypic traits (growth patterns, morphology and pathogenicity). The pathogenicity and patterns of virulence were assessed and achieved for all GP, and AMFO14 (GP 3 ) displayed the highest frequency. Based on recent taxonomic advances on Flavobacterium spp. from freshwater fish worldwide, this study provides unprecedented insights regarding CCB retrieved from tambaqui.
Probiotic potential of autochthonous bacteria from tambaqui Colossoma macropomum Suzana Kotzent, Silvia Umeda Gallani, Gustavo Moraes Ramos Valladão, Lindomar de Oliveira Alves, Fabiana Pilarski Aquaculture Research, 2021 In this study, the identification and characterization of potential probiotic bacteria present in natural microbiota of tambaqui Colossoma macromum were performed for the first time. Bacteria from the intestinal mucosa were isolated in agar Man, Rogosa and Sharpe (MRS). Only Gram-positive and haemolysis-negative isolates were selected (n = 152). The tests included morphological differentiation, gene sequencing, catalase, bile tolerance, pathogen antagonism, antimicrobial susceptibility and safety to the host. To differentiate the isolates, colonies were morphologically characterized. From 152 initial isolates, 6 strains with probiotic potential were selected and identified through sequencing of 16S rRNA gene of Enterococcus faecalis, Enterococcus hirae, Lactococcus lactis, Pediococcus pentosaceus, Staphylococcus hominis and Staphylococcus saprophyticus. The growth of the six strains was not affected by different levels of bile inclusion. All probiotic strains inhibited the growth of the Lactococcus garvieae pathogen in the antagonism test. When tested against Aeromonas hydrophila, L. lactis and E. hirae strains were prominent. All strains were resistant to some degree against the 11 antibiotics. With this study, it was possible to screen the following six strains with probiotic potential for inclusion in the diet of C. macropomum: S. hominis, S. saprophyticus, L. lactis, P. pentosaceus, E. hirae and E. faecalis.
