Editing Serial passage (section)

==Mechanism==
Serial passage can either be performed [[in vitro]] or [[in vivo]].  In the in vitro method, a virus or a strain of bacteria will be isolated and allowed to grow for a certain time.  After the sample has grown for that time, part of it will be transferred to a new environment and allowed to grow for the same period.<ref name="pmid21305003">{{Cite journal |vauthors=Chapuis É, Pagès S, Emelianoff V, Givaudan A, Ferdy JB |date=January 2011 |title=Virulence and pathogen multiplication: a serial passage experiment in the hypervirulent bacterial insect-pathogen Xenorhabdus nematophila |journal=PLOS ONE |volume=6 |issue=1 |pages=e15872 |bibcode=2011PLoSO...615872C |doi=10.1371/journal.pone.0015872 |pmc=3031541 |pmid=21305003 |doi-access=free}}</ref><ref name="pmid11844774">{{Cite journal |vauthors=Somerville GA, Beres SB, Fitzgerald JR, DeLeo FR, Cole RL, Hoff JS, Musser JM |date=March 2002 |title=In vitro serial passage of Staphylococcus aureus: changes in physiology, virulence factor production, and agr nucleotide sequence |journal=Journal of Bacteriology |volume=184 |issue=5 |pages=1430–7 |doi=10.1128/jb.184.5.1430-1437.2002 |pmc=134861 |pmid=11844774}}</ref> This process will be repeated as many times as desired.

Alternatively, an in vivo experiment can be performed where an animal is infected with a pathogen, and this pathogen allowed time to grow in that host before a sample of it is removed from the host and passed to another host.  This process is repeated for a certain number of hosts; the individual experiment determines this number.

When serial passage is performed either in vitro or in vivo, the virus or bacterium may evolve by [[mutating]] repeatedly. Identifying and studying mutations that occur often reveals information about the virus or bacterium being studied.  Accordingly, after serial passage has been performed it can be valuable to compare the resulting virus or sample of bacteria to the original, noting any mutations that have occurred and their collective effects.  Various significant outcomes may occur.  The virulence of the virus may be changed,<ref name="woo">{{Cite journal |vauthors=Woo HJ, Reifman J |date=January 2014 |title=Quantitative modeling of virus evolutionary dynamics and adaptation in serial passages using empirically inferred fitness landscapes |journal=Journal of Virology |volume=88 |issue=2 |pages=1039–50 |doi=10.1128/JVI.02958-13 |pmc=3911671 |pmid=24198414}}</ref> or a virus could evolve to become adapted to a different host environment than that in which it is typically found.<ref name="woo" /> Relatively few passages are necessary to produce a noticeable change in a virus; for instance, a virus can typically adapt to a new host within ten or so passages.<ref name="woo" />

Because serial passage allows for rapid evolution of a virus to its host, it can be used to study the evolution of antibiotic resistance; specifically, for determining what mutations could lead to the development of antibiotic resistance.<ref>{{Cite journal |vauthors=Martínez JL, Baquero F, Andersson DI |date=October 2011 |title=Beyond serial passages: new methods for predicting the emergence of resistance to novel antibiotics |journal=Current Opinion in Pharmacology |volume=11 |issue=5 |pages=439–45 |doi=10.1016/j.coph.2011.07.005 |pmid=21835695}}</ref>