title: HA222 polymorphism in Influenza A(H1N1) 2009 isolates from Intensive Care Units and ambulatory patients during three influenza seasons.
abstract: Amino acid substitutions which can affect the receptor binding specificity of the influenza virus, like the substitution of aspartic acid with glycine in position 222 of the haemagglutinin (HA) of influenza virus A(H1N1) 2009, have been associated with increased viral pathogenicity and increased tropism for the lower respiratory tract. In this paper, the polymorphic site 222 and the site 223 of the HA1 polypeptide of H1N1 2009 viruses were analyzed in order to better clarify the role of these substitutions in H1N1 2009 virus virulence. Viral strains included in this study were collected in Tuscany during 3 different influenza seasons from patients with severe as well as with mild forms of influenza caused by A(H1N1) 2009 virus. In addition, the oseltamivir resistance of the H1N1 2009 strains circulating during the same seasons was monitored with the aim to evaluate whether these changes in the HA and in neuraminidase (NA) tend to be linked and to influence each other. Altogether, the results indicate that in severe forms of influenza viral population is more variable than in mild influenza, as regards the site 222. The frequency of such substitutions varied among the three seasons, it was highest in the season 2010-2011 and very low in the season 2012-2013. However these differences were not significant.
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 48, 50134 Florence, Italy. Electronic address: f.corcioli@virgilio.it.
authors.forename: F
authors.initials: F
authors.lastname: Corcioli
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 48, 50134 Florence, Italy. Electronic address: rosaria.arvia@libero.it.
authors.forename: R
authors.initials: R
authors.lastname: Arvia
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 48, 50134 Florence, Italy. Electronic address: fede_p85@alice.it.
authors.forename: F
authors.initials: F
authors.lastname: Pierucci
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 48, 50134 Florence, Italy. Electronic address: valeriaclausi@hotmail.it.
authors.forename: V
authors.initials: V
authors.lastname: Clausi
authors.affiliation: Anesthesia and Intensive Care Unit of Emergency Department, Careggi Teaching Hospital, Largo Brambilla 3, 50134 Florence, Italy. Electronic address: bonizzolim@aou-careggi.toscana.it.
authors.forename: M
authors.initials: M
authors.lastname: Bonizzoli
authors.affiliation: Anesthesia and Intensive Care Unit of Emergency Department, Careggi Teaching Hospital, Largo Brambilla 3, 50134 Florence, Italy. Electronic address: perisa@aou-careggi.toscana.it.
authors.forename: A
authors.initials: A
authors.lastname: Peris
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Viale Morgagni 48, 50134 Florence, Italy. Electronic address: alberta.azzi@unifi.it.
authors.forename: A
authors.initials: A
authors.lastname: Azzi
mesh_terms: D000328:Adult; D000553:Ambulatory Care; D024882:Drug Resistance, Viral; D005260:Female; D005787:Gene Frequency; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D007251:Influenza, Human / Q000473:pathology* / Q000821:virology*; D007297:Inpatients; D007362:Intensive Care Units; D007558:Italy; D008297:Male; D020125:Mutation, Missense; D010045:Outpatients; D011110:Polymorphism, Genetic; D011247:Pregnancy; D014774:Virulence
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus
keywords: A(H1N1) 2009 influenza virus; Oseltamivir resistance; Pathogenicity