Abstract
BackgroundAeromonas spp. are gram-negative bacteria that can cause a variety of infections in both humans and animals and play a controversial role in diarrhea outbreaks. Our aim was to identify clinical and environmental Aeromonas isolates associated with a cholera outbreak in a northeast county of Brazil at the species level. We also aimed to determine the genetic structure of the bacterial population and the virulence potential of the Aeromonas isolates.Methods and resultsAnalysis based on concatenated sequences of the 16S rRNA and gyrB genes suggested the classification of the 119 isolates studied into the following species: A. caviae (66.9%), A. veronii (15.3%), A. aquariorum (9.3%), A. trota (3.4%), A. hydrophila (3.4%) and A. jandaei (1.7%). One isolate did not fit any Aeromonas species assessed, which might indicate a new species. The haplotype network based on 16S rRNA gene sequences identified 59 groups among the 119 isolates and 26 reference strains, and it clustered almost all A. caviae isolates into the same group. The analysis of the frequency patterns of seven virulence-associated genes (alt, ast, hlyA, aerA, exu, lip, flaA/B) revealed 29 virulence patterns composed of one to seven genes. All the isolates harbored at least one gene, and three of them harbored all seven virulence genes.ConclusionThe results emphasize the need to improve local water supply and maintain close monitoring of possible bacterial contamination in the drinking water.
Highlights
Aeromonas spp. are gram-negative bacteria that can cause a variety of infections in both humans and animals and play a controversial role in diarrhea outbreaks
Bacterial strains This study involved 119 Aeromonas spp. isolates (103 from diarrheal patient feces and 16 from the aquatic environment) obtained from March to June 2004 during a diarrhea outbreak that occurred in São Bento do Una, a Brazilian city located in Pernambuco state [7, 8]
Identification of the Aeromonas isolates at the species level Based on the phylogenetic trees generated separately by the 16S rRNA and gyrB gene sequences, a total of 31% and 11% of isolates, respectively, displayed ambiguous classification
Summary
Aeromonas spp. are gram-negative bacteria that can cause a variety of infections in both humans and animals and play a controversial role in diarrhea outbreaks. Our aim was to identify clinical and environmental Aeromonas isolates associated with a cholera outbreak in a northeast county of Brazil at the species level. A role for Aeromonas in diarrhea outbreaks remains controversial [1, 2]. Many virulence factors involved in different steps of infection mechanisms have been described in different Aeromonas species. These virulence factors include (1) fimbriae, flagella, and a capsule that allow attachment to the host surface; (2) toxins and enzymes such as
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
