Transmission of resistance

The dramatic increase of severe or lethal infections caused by antibiotic-resistant bacteria triggered numerous studies on antibiotic resistance, not only from clinical but also from environmental sources. Nowadays it is clear that environment, and water in particular, plays a central role on antibiotic resistance dispersion to and from clinical settings. However, the current state of the art clearly suggests that only a small fraction of the environmental resistome is known. The modes and mechanisms of emergence, evolution and transmission of resistance determinants are still not very well understood. Although environmental pollution is recognized to play an important role on antibiotic resistance evolution and spreading, it is still very difficult to draw cause-effect relationships, which sometimes seems to be strain/species dependent. 

Methicillin- Transmission of resistant clones of bacteria from patient to patient resistant Staphylococcus aureus (MRSA)... 

Transmission of resistant clones of bacteria from patient-to-patient and via environmental reservoirs Organisms with mutation for resistance in patient s flora selected for by antibacterial therapy absorbable, oral antibacterials and, often, an antifungal agent. 

Preventing both occurrence of resistant organisms in food and transmission of resistant organisms between species and individuals are crucial to controlling this health risk. " ... 

Resistant variants have been recovered from -30% of treated outpatient children or adults by the fifth day of therapy. Resistant variants also arise commonly in immunocompromised patients and inpatient children. Illnesses owing to apparent transmission of resistant virus associated with failure of drug prophylaxis have been documented in contacts of drug-treated ill persons in households and in nursing homes. Resistant variants appear to be pathogenic and can cause typically disabling influenza. 

Bacterial resistance to tetracyclines was first reported in 1953, very soon after their discovery (18). Tetracycline resistance is often tramposon or plasmid borne, which results in horizontal transmission of resistance factors between and amor different species. Many nonpachogenic bacteria within the environment carry resistance to tetracyclines, and they are now recognized as an important reservoir in transmission. Resistance factors may reside in this reservoir and then be transferred to pathogenic bacteria, rendering the tetracyclines useless in the control of infection-... 

If an outbreak of influenza A occurs in a patient population that includes those at risk for severe influenza disease, chemoprophylaxis with rimantadine or amantadine can be considered for the uninfected. Rimantadine has a better safety profile and is preferred. If either rimantadine or amantadine is used, it should be administered to susceptible patients (and staff) as early in the outbreak as possible. Use of rimantadine or amantadine for treatment in this setting may be problematic. Treatment of children with influenza A with rimantadine or amantadine frequently results in emergence of resistant virus during therapy. Transmission of resistant virus negates the benefit of chemoprophylaxis of susceptible contacts. A decision to use either rimantadine or amantadine for treatment of infected children should take into account the risk status of other exposed children and the likelihood that the infected child will receive benefit from therapy (e.g., benefit is diminished after 48 hours of symptoms). 

Surface modification of a contact lens can be grouped into physical and chemical types of treatment. Physical treatments include plasma treatments with water vapor (siUcone lens) and oxygen (176) and plasma polymerization for which the material surface is exposed to the plasma in the presence of a reactive monomer (177). Surfaces are also altered with exposure to uv radiation (178) or bombardment with oxides of nitrogen (179). Ion implantation (qv) of RGP plastics (180) can greatiy increase the surface hardness and hence the scratch resistance without seriously affecting the transmission of light. 

The railway lines on bridges are often electrically connected with steel or reinforced steel structures which usually have a very low grounding resistance. In new installations, an electrical separation of the rails from the bridge structure is required according to the grounding resistance of the structure and the type of rail bed. Independent of this, pipelines and metal sheathing of cables are always electrically separated from the structure in order to exclude direct transmission of stray current from the rails in these conductors. 

Viscoelastic polymers essentially dominate the multi-billion dollar adhesives market, therefore an understanding of their adhesion behavior is very important. Adhesion of these materials involves quite a few chemical and physical phenomena. As with elastic materials, the chemical interactions and affinities in the interface provide the fundamental link for transmission of stress between the contacting bodies. This intrinsic resistance to detachment is usually augmented several folds by dissipation processes available to the viscoelastic media. The dissipation processes can have either a thermodynamic origin such as recoiling of the stretched polymeric chains upon detachment, or a dynamic and rate-sensitive nature as in chain pull-out, chain disentanglement and deformation-related rheological losses in the bulk of materials and in the vicinity of interface. 

Centers for Disease Control. Nosocomial transmission of multidrug-resistant tuberenlosis among HlV-infeeted persons—Florida and New York, 1988-1991, MMWR, vol. 40, no. 34, 1991,585-591. 

In the transmission of energy by these simple machines, the conseiwation law always applies The work input equals the work output. Wlien work is done by a system, energy is transferred out of it and when work is done on a system, energy is transferred into it. When two objects interact by way of a machine (e.g. a lever), the work out of one object equals the work into the other. The work done by a person forcing one end of a lever downward equals the work done lifting a load at the other end as the lever moves upward. In any practical situation, the frictional forces resisting motion will always increase the amount of force (and work) required to do ajob. 

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