Molecular characterization of Aeromonas hydrophila and antimicrobial activities of selected medicinal plants against pathogenic isolates from water and stool samples in the era of HIV/AIDS in Limpopo Province, South Africa

Abstract

Aeromonas hydrophila is distributed widely in nature and is responsible for an array of human infections. Several studies on the isolation and characterisation of the organism abound. Although there are reports on the antibiotic resistance profiles of the organism, these reports have not been updated in Limpopo province, South Africa despite the established fact that antibiograms vary with time and geographical area. Antibiotic resistance and pathogenesis of an organism are dependent on a host of factors such as the production of extended spectrum beta-lactamases and the genetic profiles such as the genes coding for resistance and possession of integrons and how these characteristics overach with the phylogenetic inter-relatedness of isolates from different sources. In spite of the aforementioned concerns on the efficacy of antibiotics due to the acquisition or endowment of microorganisms with intrinsic and extrinsic factors , which enhances resistance to antibiotics , medicinal plants are reportedly offering promise as alternative sources of efficacious management of infections. Medicinal plants are employed by traditional healers in the management of infections in developing countries especially in Africa. However, the antimicrobial activities of medicinal plants against Aeromonas hydrophila have received only a cursory attention. In an endeavour to undertake a comprehensive study on the isolation, characterisation, antibiograms, activities of medicinal plants as well as the genetic profiles, including phylogenetics relatedness of Aeromonas isolates from different sources, stool and water samples were collected over a two year period from designated places in Limpopo Province and analysed using standard techniques applicable to the constituent research activity. The research findings are presented in six chapters as presented hereunder. The first chapter focussed on the literature review of the organism and reflects areas such as the morphology, laboratory diagnosis, clinical manifestations, pathogenesis, antimicrobial susceptibility profiles, antibacterial activities of medicinal plants as well as the genetic aspects of Aeromonas hydrophila.