Superinfection
Encyclopedia
In virology
, superinfection is the process by which a cell
, that has previously been infected by one virus
, gets coinfected
with a different strain of the virus, or another virus at a later point in time. Viral superinfections of serious conditions can lead to resistant strains of the virus, which may prompt a change of treatment. For example, an individual superinfected with two separate strains of HIV
may contract a strain that is resistant to antiretroviral treatment. The combined infection has also been shown to reduce the overall effectiveness of the immune response.
In medicine
, superinfection is an infection following a previous infection, especially when caused by microorganisms that are resistant or have become resistant to the antibiotics used earlier.
Superinfection, according to Dorland's illustrated medical dictionary, is a condition produced by sudden growth of a type of bacteria
, different from the original offenders in a wound or lesion under treatment.
lysogen, another lambda phage that infects is not able to undergo lytic
development and produce phage. The incoming phage can inject DNA
, but the DNA is immediately shut down and no transcription/translation of the lambda initiates. Therefore, lambda lysogens are immune to infection by another lambda phage particle. The reason is that the lysogen is continuously producing cI repressor. The amount of cI protein
exceeds the amount needed to shut down more than one phage. The extra repressor binds to the superinfecting phage DNA and prevents its transcription.
Virology
Virology is the study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit cells for virus reproduction, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy...
, superinfection is the process by which a cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
, that has previously been infected by one virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
, gets coinfected
Coinfection
In parasitology, coinfection is the term used to describe the simultaneous infection of a host by multiple pathogen species. In virology, coinfection can also refer to the simultaneous infection of a single cell by two or more virus particles...
with a different strain of the virus, or another virus at a later point in time. Viral superinfections of serious conditions can lead to resistant strains of the virus, which may prompt a change of treatment. For example, an individual superinfected with two separate strains of HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
may contract a strain that is resistant to antiretroviral treatment. The combined infection has also been shown to reduce the overall effectiveness of the immune response.
In medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, superinfection is an infection following a previous infection, especially when caused by microorganisms that are resistant or have become resistant to the antibiotics used earlier.
Superinfection, according to Dorland's illustrated medical dictionary, is a condition produced by sudden growth of a type of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, different from the original offenders in a wound or lesion under treatment.
Superinfection immunity in Lambda phage
When a cell is a lambdaLambda phage
Enterobacteria phage λ is a temperate bacteriophage that infects Escherichia coli.Lambda phage is a virus particle consisting of a head, containing double-stranded linear DNA as its genetic material, and a tail that can have tail fibers. The phage particle recognizes and binds to its host, E...
lysogen, another lambda phage that infects is not able to undergo lytic
Lytic cycle
The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle. The lytic cycle is typically considered the main method of viral replication, since it results in the destruction of the infected cell...
development and produce phage. The incoming phage can inject DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
, but the DNA is immediately shut down and no transcription/translation of the lambda initiates. Therefore, lambda lysogens are immune to infection by another lambda phage particle. The reason is that the lysogen is continuously producing cI repressor. The amount of cI protein
CI protein
cI protein , also known as the lambda repressor, is the sole protein expressed in the lysogenic state of Lambda phage. cI turns off transcription at the phage's L and R promoters as well as any other invading lambda phages into the host cell. It is a transcription factor and contains the common...
exceeds the amount needed to shut down more than one phage. The extra repressor binds to the superinfecting phage DNA and prevents its transcription.
See also
- CoinfectionCoinfectionIn parasitology, coinfection is the term used to describe the simultaneous infection of a host by multiple pathogen species. In virology, coinfection can also refer to the simultaneous infection of a single cell by two or more virus particles...
- ReassortmentReassortmentReassortment is the mixing of the genetic material of a species into new combinations in different individuals. Several different processes contribute to reassortment, including assortment of chromosomes, and chromosomal crossover. It is particularly used when two similar viruses that are infecting...
- Antibiotic resistanceAntibiotic resistanceAntibiotic resistance is a type of drug resistance where a microorganism is able to survive exposure to an antibiotic. While a spontaneous or induced genetic mutation in bacteria may confer resistance to antimicrobial drugs, genes that confer resistance can be transferred between bacteria in a...
- HIV superinfectionHIV SuperinfectionHIV superinfection is a condition in which a person with established human immunodeficiency virus infection acquires a second strain of the virus...