Abstract
Aeromonas hydrophila is widely distributed throughout the world and causes diseases to animals and human exposed to contaminated environments such as water and soil. This study aimed to compare between isolates of A. hydrophila collected from clinical and environmental samples, through investigating the phenotype of some virulence factors in vitro, including hemolysin, protease, lipase, nuclease and biofilm formation ability. Also, the antimicrobial susceptibility for different antibiotics was determined using disc diffusion method. For genotypic identification of isolates and phylogenetic tree construction, 16S rDNA target gene was amplified and sequenced. The phenotypic results showed some differences between the isolates (clinical and environmental). All isolates were resistance to clindamycin, amoxicillin and erythromycin while susceptible to gentamicin, amikacin and vancomycin. Sequences of 16S rDNA confirmed the identification of the studied bacteria as A. hydrophila with 99-100% , and identity and phylogenetic tree by neighbor-joining clearly separated the isolates in a branching pattern which displayed similarity to the GenBank isolates obtained from Asian regions. The clinical isolates showed less polymorphism than the environmental isolates.
Highlights
Aeromonas hydrophila is an ubiquitous, aerobic, Gram negative, mesophilic and motile bacteria
Out of eight isolates of A. hydrophila, 4 (18.2%) isolates were collected from clinical specimens and from environmental samples, and 4 (11.4%) isolates were obtained from different soil samples of plant rhizospheres
The experimental results of some virulence factors of A. hydrophila showed that all clinical isolates had β-hemolytic activity on blood agar media while the environmental ones had γ- hemolytic activity
Summary
Aeromonas hydrophila is an ubiquitous, aerobic, Gram negative, mesophilic and motile bacteria. It is isolated from aquatic environments, fish, various food products [1] and soil[2]. It is usually involved in human infections such as septicemia, gastroenteritis, cellulitis, wound sepsis with necrosis, gangrene, pneumonia and traveler’s diarrhea, resulting from improper handling or consumption of contaminated food [3]. The pathogenesis of A. hydrophila is complex and involves many virulence factors [4]. A. hydrophila produces several extracellular products such as proteases, haemolysins, aerolysin, cytolytic enterotoxins that are related with virulence [5]. The genes coding for these virulence factors might be differentially expressed in Aeromonas species depending on the environmental conditions of water or the host [8]
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.
