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The spectrum in a rainbow. A spectrum (pl.: spectra or spectrums) [1] is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word spectrum was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism.
A colored electron microscopy image of methicillin-resistant staphylococcus aureus (), a bacterium commonly targeted by broad-spectrum antibioticsA broad-spectrum antibiotic is an antibiotic that acts on the two major bacterial groups, Gram-positive and Gram-negative, [1] or any antibiotic that acts against a wide range of disease-causing bacteria. [2]
They are broad-spectrum systemic insecticides, applied as sprays, drenches, seed and soil treatments. Although the classic risk assessment considered this insecticide group (and flupyradifurone specifically) safe for bees , novel research [ 37 ] has raised concern on their lethal and sublethal effects, alone or in combination with other ...
Parabens are active against a broad spectrum of microorganisms. However, their antibacterial mode of action is not well understood. They are thought to act by disrupting membrane transport processes [2] or by inhibiting synthesis of DNA and RNA [3] or of some key enzymes, such as ATPases and phosphotransferases, in some bacterial species. [4]
This is the spectrum of a blue sky somewhat close to the horizon, looking east with the sun to the west at around 3–4 pm on a clear day. A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby ...
β-Lactam antibiotics are indicated for the prevention and treatment of bacterial infections caused by susceptible organisms. At first, β-lactam antibiotics were mainly active only against gram-positive bacteria, yet the recent development of broad-spectrum β-lactam antibiotics active against various gram-negative organisms has increased their usefulness.
This involves the administration of a broad-spectrum antibiotic based on the signs and symptoms presented and is initiated pending laboratory results that can take several days. [34] [35] When the responsible pathogenic microorganism is already known or has been identified, definitive therapy can be started. This will usually involve the use of ...
Narrow-spectrum antibiotics have low propensity to induce bacterial resistance and are less likely to disrupt the microbiome (normal microflora). [3] On the other hand, indiscriminate use of broad-spectrum antibiotics may not only induce the development of bacterial resistance and promote the emergency of multidrug-resistant organisms, but also cause off-target effects due to dysbiosis.