Antimicrobial resistance patterns and transferable traits in Enterobacteriaceae isolates from poultry in Tlemcen, Algeria

Background: Antibiotics are overused in poultry industry, and this has resulted in the emergence of multidrug resistant (MDR) bacteria. The current study is aimed at determining antimicrobial resistance (AMR) patterns of Enterobacteriaceae isolates from poultry in the west of Algeria.Methodology: Different chicken samples (kidney, bone and intestine) were collected and processed for culture using standard microbiological methods to isolate Enterobacteriaceae. Isolates were identified biochemically using API 20E, while isolated Escherichia coli was typed for O1, O2 and O78 antigens using slide agglutination with specific antisera. All identified isolates were tested against 26 antibiotic disks using the Kirby Bauer disk diffusion method according to the CLSI standards. The minimum inhibitory concentrations (MICs) of chloramphenicol, tetracycline, nalidixic acid, ofloxacin and ciprofloxacin were determined for selected isolates. Conjugative plasmid transfer, plasmid incompatibility and colicin tests were used to detect transferable resistance traits in 48 selected E. coli isolates.Results: One hundred and thirty-eight bacteria species were isolated, which included Escherichia coli (n=107), Salmonella spp (n=11), Klebsiella spp (n=8), Enterobacter spp (n=7), Pseudomonas spp (n=3) and Citrobacter spp (n=2). Serotyping identified 24 agglutinable E. coli isolates with O78:K80 (n=11), O1:K1 (n=9) and O2:K1 (n=4). Antibiotic susceptibility showed high frequency of E. coli resistance to nalidixic acid (89.7%), tetracycline (82.2%), streptomycin (82.2%), nitrofurantoin (68.2%), ampicillin (45.8%), ticarcillin (44.9%), piperacillin(42.1%), and chloramphenicol (15.9%). The percentage of multi-drug resistance isolates (resistance to more than 3 antibiotic classes) was 87.9%. The results of conjugative transfer in 48 E. coli isolates shows that the most important resistance traits transferred by plasmids are ASTeSuTmp (18.5%) and SuTmp (12.3%).Conclusion: This study confirmed the presence of multiple antibiotic resistant E. coli and other members of family Enterobacteriaceae in poultry in Algeria, and showed that these antibiotic resistance traits are easily disseminated by plasmids, with dire consequences on human health. Keywords : Poultry, Enterobacteriaceae, antimicrobial resistance, conjugation, plasmid.   French title:  Profils de résistance aux antimicrobiens et caractères transférables des isolats d'entérobactéries provenant de volailles à Tlemcen, Algérie   Contexte: Les antibiotiques sont surutilisés dans l'industrie de la volaille, ce qui a entraîné l'émergence de bactéries multirésistantes (MDR). L'étude actuelle vise à déterminer les profils de résistance aux antimicrobiens (RAM) des isolats d'Enterobacteriaceae provenant de volailles dans l'ouest de l'Algérie.  Méthodologie: Différents échantillons de poulet (rein, os et intestin) ont été prélevés et traités pour la culture en utilisant des méthodes microbiologiques standard pour isoler les Enterobacteriaceae. Les isolats ont été identifiés biochimiquement en utilisant l'API 20E, tandis que Escherichia coli isolé a été typé pour les antigènes O1, O2 et O78 en utilisant l'agglutination sur lame avec des antisérums spécifiques. Tous les isolats identifiés ont été testés contre 26 disques antibiotiques en utilisant la méthode de diffusion sur disque de Kirby Bauer selon les normes CLSI. Les concentrations minimales inhibitrices (CMI) du chloramphénicol, de la tétracycline,de l'acide nalidixique, de l'ofloxacine et de la ciprofloxacine ont été déterminées pour certains isolats. Des tests de transfert plasmidique conjugatif, d'incompatibilité plasmidique et de colicine ont été utilisés pour détecter des traits de résistance transférables dans 48 isolats sélectionnés d'E. coli.Résultats: Cent trente-huit espèces de bactéries ont été isolées, parmi lesquelles Escherichia coli (n=107), Salmonella spp (n=11), Klebsiella spp (n=8), Enterobacter spp (n=7), Pseudomonas spp (n=3) et Citrobacter spp (n=2). Le sérotypage a identifié 24 isolats d'E. coli agglutinables avec O78: K80 (n=11), O1: K1 (n=9) et O2: K1 (n=4). La sensibilité aux antibiotiques a montré une fréquence élevée de résistance d'E. coli à l'acide nalidixique (89,7%), à la tétracycline (82,2%), à la streptomycine (82,2%), à la nitrofurantoïne (68,2%), àl'ampicilline (45,8%), à la ticarcilline (44,9%), à la pipéracilline (42,1%) et le chloramphénicol (15,9%). Le pourcentage d'isolats de résistance multi-médicaments (résistance à plus de 3 classes d'antibiotiques) était de 87,9%. Les résultats du transfert conjugatif dans 48 isolats d'E. coli montrent que les traits de résistance les plus importants transférés par les plasmides sont ASTeSuTmp (18,5%) et SuTmp (12,3%).Conclusion: Cette étude a confirmé la présence de multiples E. coli résistants aux antibiotiques et d'autres membres de la famille des Enterobacteriaceae chez les volailles en Algérie et a montré que ces traits de résistance aux antibiotiques sont facilement disséminés par les plasmides, avec des conséquences désastreuses sur la santé humaine. Mots clés: volaille, entérobactéries, résistance aux antimicrobiens, conjugaison, plasmide

Effect of heat treatment with CdCl2 on the electrodeposited CdTe/CdS heterojunction

CdS/CdTe heterojunction was subjected to chemical treatment commonly used in photovoltaic device fabrication to determine the resulting microscopic effect on the morphology and structure. CdS and CdTe thin films were electrodeposited successively onto indium tin oxide (ITO) from aqueous solution. Containing CdCl2 and Na2S2O3 for the deposition of thin film windows, the ITO/CdS resulting substrates was then used for the deposition of CdTe thin film absorber using aqueous solution of CdSO4 and TeO2. Next CdCl2 dip followed by 400°C heat treatment was used to modify the CdTe/CdS surface and interface. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) were used to evaluate the resulting surface morphology. X-ray diffraction analysis reveals that the heat treatment enhances the recrystallisation and shifts the CdTe peaks towards a smaller lattice parameter.CdS/CdTe heterojunction was subjected to chemical treatment commonly used in photovoltaic device fabrication to determine the resulting microscopic effect on the morphology and structure. CdS and CdTe thin films were electrodeposited successively onto indium tin oxide (ITO) from aqueous solution. Containing CdCl2 and Na2S2O3 for the deposition of thin film windows, the ITO/CdS resulting substrates was then used for the deposition of CdTe thin film absorber using aqueous solution of CdSO4 and TeO2. Next CdCl2 dip followed by 400°C heat treatment was used to modify the CdTe/CdS surface and interface. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) were used to evaluate the resulting surface morphology. X-ray diffraction analysis reveals that the heat treatment enhances the recrystallisation and shifts the CdTe peaks towards a smaller lattice parameter

Physical properties of CdSexTe1-x thin films prepared by electrodeposition

The cadmium chalcogenides CdSexTe1-x (0≤x ≤1 ) thin films have been electrodeposited onto ITO coated glass substrates from an acid sulphate solution at 90 °C. The structure, the composition and the morphology have been studied as a function of the x coefficient by XRD, EDAX, optical absorbance and AFM techniques. All deposits have a cubic structure with a preferred orientation along the (111) direction. The composition in the films is found to vary linearly with the composition in the solution. The increase of the amount of tellurium in the CdSexTe1-x films decreases the band gap down to 1.35 eV and increases the lattice constant. The photoelectrochemical studies in a polysulfide electrolyte show that CdSexTe1-x thin films behave as n-type semiconductors.The cadmium chalcogenides CdSexTe1-x (0≤x ≤1 ) thin films have been electrodeposited onto ITO coated glass substrates from an acid sulphate solution at 90 °C. The structure, the composition and the morphology have been studied as a function of the x coefficient by XRD, EDAX, optical absorbance and AFM techniques. All deposits have a cubic structure with a preferred orientation along the (111) direction. The composition in the films is found to vary linearly with the composition in the solution. The increase of the amount of tellurium in the CdSexTe1-x films decreases the band gap down to 1.35 eV and increases the lattice constant. The photoelectrochemical studies in a polysulfide electrolyte show that CdSexTe1-x thin films behave as n-type semiconductors

Anomalous strength of membranes with elastic ridges

We report on a simulational study of the compression and buckling of elastic ridges formed by joining the boundary of a flat sheet to itself. Such ridges store energy anomalously: their resting energy scales as the linear size of the sheet to the 1/3 power. We find that the energy required to buckle such a ridge is a fixed multiple of the resting energy. Thus thin sheets with elastic ridges such as crumpled sheets are qualitatively stronger than smoothly bent sheets.Comment: 4 pages, REVTEX, 3 figure

Simple system using natural mineral water for high-throughput phenotyping of Arabidopsis thaliana seedlings in liquid culture

Background: Phenotyping for plant stress tolerance is an essential component of many research projects. Because screening of high numbers of plants and multiple conditions remains technically challenging and costly, there is a need for simple methods to carry out large-scale phenotyping in the laboratory.Methods: We developed a method for phenotyping the germination and seedling growth of Arabidopsis (Arabidopsis thaliana) Col-0 in liquid culture. Culture was performed under rotary shaking in multiwell plates, using Evian natural mineral water as a medium. Nondestructive and accurate quantification of green pixels by digital image analysis allowed monitoring of growth. Results: The composition of the water prevented excessive root elongation growth that would otherwise lead to clumping of seedlings observed when classic nutrient-rich medium or deionized water is used. There was no need to maintain the cultures under aseptic conditions, and seedlings, which are photosynthetic, remained healthy for several weeks. Several proof-of-concept experiments demonstrated the usefulness of the approach for environmental stress phenotyping. Conclusion: The system described here is easy to set up, cost-effective, and enables a single researcher to screen large numbers of lines under various conditions. The simplicity of the method clearly makes it amenable to high-throughput phenotyping using robotics

Aortic valve replacement with the minimal extracorporeal circulation (Jostra MECC System) versus standard cardiopulmonary bypass: A randomized prospective trial

AbstractBackgroundWe prospectively evaluated a newly introduced minimal extracorporeal circulation system (Jostra MECC System; Jostra AG, Hirrlingen, Germany) for aortic valve surgery.MethodIn a prospective, randomized study, 100 patients underwent aortic valve replacement either with standard cardiopulmonary bypass (n = 50, group B) or with the MECC System (n = 50, group B). The myocardial protection and the left vent were identical for the two groups. The intrapericardial suction device was never used (only the cell salvage device was used) to reduce the air-blood contact area.ResultsNo significant differences were noted in patient characteristics and operative data between groups. Operative mortality (<30 days) was 2% for group A and 4% for group B (difference not significant). From the preoperative period to the postoperative period, the increase in C-reactive protein was significantly higher for group B (P < .001). The postoperative troponin I level was significantly lower in group A (mean 4.65 ± 2.9 μg/L at 24 hours) than in group B (8.2 ± 4.4 μg/L, P < .03). On the other hand, the MECC System was associated with platelet preservation. Renal function was better preserved and the neurologic event rate was significantly lower for the MECC group (P < .02).ConclusionThe MECC System is safe and allows aortic valve replacement under the most favorable conditions. The system is more biocompatible than standard cardiopulmonary bypass and provides a good postoperative biologic profile and good clinical results, particularly for high-risk patients

Assessing the efficiency of filters protecting base soil subject to erosion

Dams filters are mainly designed using filter criteria based on the grain size distribution (Sherard & Dunnigan, 1985). This paper reports experimental results obtained on the soil-filter system behaviour subject to different hydraulic and geometrical conditions. A silt soil and three sandy gravels were used as the core and different filters (F1, F2 and F3), respectively. The objective of this study was to determine the effectiveness of the filter to protect the silt submitted to erosion under controlled water flow (horizontal and vertical configurations). Particles transport and filtration through each granular filter were analysed as regards to filter retention capacity, particles size selection and grains shape. This study was achieved by conducting a comparison of the behaviour of the three filters against the silt erosion. A comparison of the efficiency of the filters is assessed toward the required usual relationship criterion and the most appropriate for the dam filters