Cross-Resistance to Insecticides in a Malathion-Resistant Strain of Ceratitis capitata (Diptera: Tephritidae)

Abstract

Infections caused by multidrug-resistant (MDR) bacteria, including Vancomycin-Resistant Enterococcus (VRE), have become one of the greatest clinical challenges of the 21 st century. Particularly, VRE strains of E. faecium, a natural member of the gastrointestinal consortia, have recently emerged as one of the most problematic cases of MDR nosocomial pathogens. It is widely known that the establishment of high-level intestinal colonization of this bacterium, triggered by antibiotic treatment of the host, potentially leads to bacteremia, endocarditis and surgical wound, urinary tract, and devicerelated infections in hospitalized patients. However, the unique determinants possessed by these strains, which enable them to benefit from the antibiotic-induced perturbations of the gut microbiota and host intestinal immune defenses, remain to be identified.Essentially, what needs to be revealed is the differential gene expression of E. faecium in its niche at different time points; before and during antibiotic treatment of the host, and very interestingly, in the presence of probiotic bacteria. Differentially expressed genes will highlight how and why E. faecium is able to dominate the gut, as well as how it interacts with its surroundings, possibly pinpointing its potential weaknesses, as well as provide hints on what specific properties should be prerequisites for bacteria to be used as probiotics.Since the global expression intended to be analyzed is that of E. faecium alone, a method to separate this bacteria from the rest of the gut microbiota is required. Failure to do so would result in the study of the gut microbiota's transcriptome as a whole: metatranscriptomics. In practice, the separation VRE. faecium from the rest of the commensal microbiota could be carried out by means of flow cytometry if the generation of a fluorescent E. faecium was achieved. Additionally, it would serve as a great tool to study a series of facets of VRE faecium colonization which remain virtually unknown. It would enable the monitorization of VRE infection through whole-body imaging of infected mice, fluorescence microscopy analysis of histological cuts to determine its most predominant locations, the use of FbFP as a translational or transcriptional reporter, etc.Consequently, the main objective of this Final Degree Project has been to attempt the generation of a Vancomycin-Resistant Enterococcus faecium clinical isolate (C68) expressing a fluorescent protein whose chromophore can form under the anaerobic conditions found in the guts of animals: (FMN)-based fluorescent protein (FbFP).In order to fulfill the main objective of this work, first, the FbFP gene was synthesized with the appropriate features for its expression in E. faecium and for its cloning. Next, the plasmid construction aimed to confer E. faecium fluorescent properties (pBT2-FbFP), was generated. This was done by inserting the FbFP gene into the pBT2 plasmid. As a previous step to the transformation of E. faecium, pBT2-FbFP was transformed into E.coli DH5a in or...

Insecticidal and acetylcholinesterase inhibitory activities of Lamiaceae plant essential oils and their major components against Drosophila suzukii (Diptera: Drosophilidae)

“…However, this method based on insecticides poses development of insecticide resistance and adverse effects on environment and human health (Couso-Ferrer et al, 2011;Jin et al, 2011). These problems have highlighted the need for the development of new strategies for pest control.…”

Residual toxicity of insecticides used in Tunisian citrus orchards on the imported parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae): Implications for IPM program of Ceratitis capitata (Diptera: Tephritidae)

“…More recently, the new European legislations regarding the use of insecticides and their tolerated residues in imported commodities (OJEU, 2009), as well as the emergence of resistance and cross resistance to many commonly used insecticides in Mediterranean populations of C. capitata forced stakeholders to review control strategies adopted against this economic pest (Magaña et al, 2007;Couso-Ferrer et al, 2011;Vontas et al, 2011;Arouri et al, 2015). As result, alternative control tactics were introduced and promoted in Tunisia including mass trapping and attract-andkill techniques leading, when properly applied, to a relative decrease in the frequency of insecticide applications (Boulahia-Kheder et al, 2012;Braham, 2013;Navarro Llopis et al, 2013;Hafsi et al, 2015).…”

Perspectiva do emprego de limonoides do nim (Azadirachta indica) no controle comportamental de Ceratitis capitata (Diptera: Tephritidae)

“…O controle dessa espécie é um sério problema em países tropicais, agravando a situação em projetos de irrigação em função da diversidade e disponibilidade de frutos hospedeiros. Ademais, o risco de evolução da resistência de C. capitata a inseticidas sintéticos é um problema eminente (MAGAÑA et al, 2007, COUSO-FERRER et al, 2011.…”