N-Acylhomoserine Lactones (AHLs), QseB/C Gene Detection, Virulence Factors and Antibiotics Resistance of &amp;lt;i&amp;gt;Aeromonas hydrophila&amp;lt;/i&amp;gt;

Emmanuel Konadu Sarkodie,Weihua Chu,Shuxin Zhou

doi:10.4236/aim.2019.95030

Abstract

The aim of this research was to detect the N-acyl homoserine lactones (AHLs) production and QseB/C gene of Aeromonas hydrophila. We analyzed the potentials of these isolates of Aeromonas hydrophila in causing biofilm formation, hemolysis, protease, and lipase. The antibiotic susceptibility of the 15 Aeromonas hydrophila isolates was also investigated. The detection of AHLs was carried out using the Chromobacterium violaceum strain CV026 as biosensors. The isolated strains were tested for the reaction of C. violaceum CV026 by cross-streaking on an agar plate. Production of AHLs was determined by the diffusing via the agar plates and the tinge of the biosensor strains. All isolated strains produced AHLs. A polymerase chain reaction (PCR) showed the isolated strains had qseB and qseC genes. Susceptibility tests of A. hydrophila isolates were administered against 25 different antibiotic disks representing 12 classes of antibiotics. The strains were highly resistant to β-Lactam with 96.7% showing resistibility, whereas 97.7% susceptibility was found towards Aminoglycoside class of the antibiotic used. 60% showed intermediate resistant to Polypeptide. 100% of the strains showed no resistant to Aminoglycoside, Polypeptide, Monobactam, and Carbapenems class of antibiotics. Each of the isolates was found to be associated with at least one virulent factor. Our results clearly demonstrated that there is a presence of QseB/C genes in A. hydrophila and also produces AHLs molecule and virulence factors. The investigated isolates showed the pathogenic potential of Aeromonas hydrophila which makes it a serious threat to public health.

Highlights

Aeromonads are a group of bacteria with multicellular functioning
Our results clearly demonstrated that there is a presence of QseB/C genes in A. hydrophila and produces acyl homoserine lactones (AHLs) molecule and virulence factors
N-acylhomoserine lactone (AHL)-based Quorum sensing (QS) system, has been found to be one of the autoinducers that exist in A. hydrophila and a cross talk exist between AHLs and QseBC systems in A. hydrophila [10]

Summary

Introduction

Aeromonads are a group of bacteria with multicellular functioning. The genus Aeromonas belongs to Aeromonadaceae family [1] and within the Gammaproteobacteria subclass. A. hydrophila forms part of thirty-two validated species in the genus Aeromonas [2] and typifies the high levels of antimicrobial resistance, resulting in difficulties in treating infections in the aquaculture industry. The genus Aeromonas has been categorized into two major groups: Motile, mesophilic species that cause disease in humans, and Non-motile, psychrophilic species that generally cause disease only in fish. They are deemed as an important Aeromonas species, liable for an array of human infectious diseases. The widespread use of antimicrobial agents as a control mechanism in human and animal epidemics has resulted in an increase of antimicrobial resistance, in pathogenic bacteria and in commensal and environmental bacteria [11]. Very little is known about environmental strains regardless of the extensive report on antibiotic susceptibility of clinical isolates of Aeromonas spp. 99% resistant methicillin, rifampicin, bacitracin, and novobiocin were observed in all tested strains of A. hydrophila

Objectives

Methods

Results

Conclusion