The mechanisms governing the epidemiology dynamics and success determinants of a specific healthcare-associated methicillin-resistant S. aureus (HA-MRSA) clone in hospital settings are still unclear. Important epidemiological changes have occurred in Europe since 2000 that have been related to the appearance of the ST22-IV clone. Between 2006 and 2010, we observed the establishment of the ST22-IV clone displacing the predominant Italian clone, ST228-I, in a large Italian university hospital. To investigate the factors associated with a successful spread of epidemic MRSA clones we studied the biofilm production, the competitive behavior in co-culture, the capacity of invasion of the A549 cells, and the susceptibility to infection in a murine model of acute pneumonia of the two major HA-MRSA clones, ST22-IV and ST228-I. We showed that persistence of ST22-IV is associated with its increased biofilm production and capacity to inhibit the growth of ST228-I in co-culture. Compared to ST228-I, ST22-IV had a significantly higher capacity to invade the A549 cells and a higher virulence in a murine model of acute lung infection causing severe inflammation and determining death in all the mice within 60 hours. On the contrary, ST228-I was associated with mice survival and clearance of the infection. ST22-IV, compared with ST228-I, caused a higher number of persistent, long lasting bacteremia. These data suggest that ST22-IV could have exploited its capacity to i) increase its biofilm production over time, ii) maintain its growth kinetics in the presence of a competitor and iii) be particularly invasive and virulent both in vitro and in vivo, to replace other well-established MRSA clones, becoming the predominant European clone. © 2012 Baldan et al.

Factors contributing to epidemic MRSA clones replacement in a hospital setting / R. Baldan, F. Testa, N.I. Lorè, A. Bragonzi, P. Cichero, C. Ossi, A. Biancardi, P. Nizzero, M. Moro, D.M. Cirillo. - In: PLOS ONE. - ISSN 1932-6203. - 7:8(2012), pp. e43153.e43153-e43153.1.

Factors contributing to epidemic MRSA clones replacement in a hospital setting

F. Testa
Secondo
;
2012

Abstract

The mechanisms governing the epidemiology dynamics and success determinants of a specific healthcare-associated methicillin-resistant S. aureus (HA-MRSA) clone in hospital settings are still unclear. Important epidemiological changes have occurred in Europe since 2000 that have been related to the appearance of the ST22-IV clone. Between 2006 and 2010, we observed the establishment of the ST22-IV clone displacing the predominant Italian clone, ST228-I, in a large Italian university hospital. To investigate the factors associated with a successful spread of epidemic MRSA clones we studied the biofilm production, the competitive behavior in co-culture, the capacity of invasion of the A549 cells, and the susceptibility to infection in a murine model of acute pneumonia of the two major HA-MRSA clones, ST22-IV and ST228-I. We showed that persistence of ST22-IV is associated with its increased biofilm production and capacity to inhibit the growth of ST228-I in co-culture. Compared to ST228-I, ST22-IV had a significantly higher capacity to invade the A549 cells and a higher virulence in a murine model of acute lung infection causing severe inflammation and determining death in all the mice within 60 hours. On the contrary, ST228-I was associated with mice survival and clearance of the infection. ST22-IV, compared with ST228-I, caused a higher number of persistent, long lasting bacteremia. These data suggest that ST22-IV could have exploited its capacity to i) increase its biofilm production over time, ii) maintain its growth kinetics in the presence of a competitor and iii) be particularly invasive and virulent both in vitro and in vivo, to replace other well-established MRSA clones, becoming the predominant European clone. © 2012 Baldan et al.
adult; aged; animal experiment; animal model; animal tissue; article; bacterial clearance; bacterial colonization; bacterial growth; bacterial mutation; bacterial strain; bacterial virulence; bacterium competence; biofilm; clone; coculture; controlled study; epidemic; growth rate; healthcare associated infection; human; in vitro study; in vivo study; infection sensitivity; lobar pneumonia; major clinical study; methicillin resistant Staphylococcus aureus; mouse; nonhuman; strain difference; strain identification; survival; surveillance; infection; virulence; cells; evolution; biofilm; fitness; period; toxin
Settore BIO/10 - Biochimica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/249656
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