Virology Division News
Bacteriophage PM2 nomenclature revision
, J. M. Tomás
, and J. Maniloff
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Barcelona, Spain
Department of Microbiology and Immunology, University of Rochester, School of Medicine and Dentistry,
Rochester, New York, U.S.A
Summary. Two taxonomically different bacteriophages have unintentionally been given
the same name. Alteromonas phage PM2, isolated in 1968, is the type species of the family
Corticoviridae, genus Corticovirus: lipid-containing, icosahedral viruses containing circu-
lar dsDNA. Aeromonas phage PM2, isolated in 1990, is a tailed virus, with contractile tail,
and presumably a member of the family Myoviridae: phages with contractile tails, contain-
ing linear dsDNA. To avoid confusion, the name of Aeromonas phage PM2 is now changed
to phage AehPM2.
A lipid-containing bacteriophage was isolated from seawater in 1968 . This phage was
named PM2, and a taxon established for it in 1971 in the 1st Report of the International
Committee on Taxonomy of Viruses (ICTV) . As described in the most recent (6th)
ICTV Report, phage PM2 is the type species of the family Corticoviridae, genus Cortico-
virus: lipid-containing, icosahedral viruses, containing circular dsDNA and infecting the
marine bacterium Alteromonas .
Subsequently, in 1990, a phage infecting the marine bacterium Aeromonas hydrophila
was isolated, characterized, and inadvertently also named PM2 . The Aeromonas phage
PM2 is a tailed virus, with contractile tail, and presumably is a member of the family
Myoviridae: phages with contractile tails, containing linear dsDNA . Indeed, Aeromonas
PM2 phage resembles two previous Myoviridae isolates from Aeromonas hydrophila,
phages Aeh1 and Aeh2 .
To avoid confusion between the two taxonomically very different phages named PM2
and in view of the historical priority of Alteromonas phage PM2, the name of Aeromonas
phage PM2 is now changed to Aeromonas phage AehPM2.
1. Ackermann H-W (1995) Family Corticoviridae. In: Murphy FA, Fauquet CM, Bishop DHL, Ghabrial SA,
Jarvis AW, Martelli GP, Mayo MA and Summers MD (eds) Virus Taxonomy. Classification and Nomencla-
ture of Viruses. Sixth Report of the International Committee on Taxonomy of Viruses. Springer, Wien New
York, pp 67–69 (Arch Virol [Suppl] 10)