No abstract

BackgroundAntimicrobial resistance has become one of the most severe global threats to human and veterinary Medicine. colistin is an effective therapeutic agent against multi-drug-resistant pathogens. However, the discovery of transferable plasmids that confer resistance to colistin (mcr-1) has led to challenges in medical science. This study describes the role of wild birds in the harbouring and environmental spread of colistin-resistant bacteria, which could pose a potential hazard to human and animal health.MethodsIn total, 140 faecal samples from wild birds (migratory and resident birds) were tested. Twenty surface water samples were collected from the area in which wild bird trapping was conducted, and 50 human stool samples were collected from individuals residing near the surface water sources and farm buildings. Isolation and identification of Enterobacteriaceae and Pseudomonas aeruginosa from the different samples were performed using conventional culture techniques and biochemical identification. PCR amplification of the mcr genes was performed in all positive isolates. Sequencing of mcr-1 genes from three randomly selected E. coli carrying mcr-1 isolates; wild birds, water and humans was performed.ResultThe bacteriological examination of the samples showing isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and P. aeruginosa. The results of multiplex PCR of the mcr genes revealed that E. coli was the most prevalent gram-negative bacterium harbouring the mcr genes, whereas a low prevalence was observed for K. pneumoniae. The prevalence of mcr-1 in resident birds, migratory birds, water sources and humans were 10.4, 20,16.6 and 9.6% while the prevalence of mcr-2 were 1.4, 3.6, 11.1 and 9.6%, respectively. Sequencing of the mcr-1 gene from the three E. coli carrying mcr-1 isolates indicated a possible correlation between the wild bird and surface water isolates.ConclusionThe detection of mcr-1-positive bacteria in wild birds in Egypt indicates the possible environmental dissemination of this gene through bird activity. The impact of the interaction between domestic and wild animals on public health cannot be overlooked.

No abstract

No abstract

The majority of carbonate reservoirs have low porosity and permeability in general because of having a high amount of matrixes that make a heterogeneous reservoir, however high permeable layers are fractured. This study shows the effect of carbon dioxide injection on the oil recovery factor using an ECLIPSE 300 compositional reservoir simulator for 3D modelling and the change of carbonate components reaction during CO 2 injection in experimental work. In addition, a high recovery factor has been recorded during miscible CO 2 injection compared to immiscible injection. Water alternative gas (WAG) has been used as an enhanced oil recovery (EOR) method to overcome an unfavourable mobility ratio of CO 2 flooding. Miscible CO 2 injection with the aid of WAG has also had a great impact on the dissolution of carbonate components in dissolving calcite and dolomite components. Consequently, CO 2 flooding has a relatively low recovery factor without any EOR techniques such as gravity stable displacement, WAG or mobility control. CO 2 injection below minimum miscibility pressure (MMP) reduces CO 2 emission, while it takes too long time to maintain reservoir pressure. On the other hand, CO 2 flooding above MMP improves pressure maintenance; causes oil swelling, and increases the oil density.