Listeria monocytogenes and USA300 methicillin-resistant Staphylococcus aureus (USA300) are significant Gram-positive pathogens of increasing importance to public health and food and health-care industries worldwide. Severe invasive infections associated with these pathogens are due to a limited number of epidemic clones (ECs), which now cause significant morbidity and mortality around the world. In particular, USA300 is increasingly a major cause of both community- and hospital-acquired (HA) infections. Novel sequence-based subtyping methods have the potential to accurately identify the routes by which these ECs spread to humans, which then allows establishment of more effective intervention strategies. Application of multi-virulence-locus sequence typing (MVLST) to L. monocytogenes revealed 87 different MVLST-defined sequence types or Virulence Types (VTs) among a total of 296 isolates obtained from several outbreaks, sporadic cases, and food and environmental sources worldwide. About 60% of the isolates belonged to one of the seven currently identified ECs of L. monocytogenes, suggesting that ECs can persist and transmit during the intervals between outbreaks. Most recently, ECV was associated with the 2008 listeriosis outbreak linked to deli meats in Canada and ECVI and VII were associated with the 2011 listeriosis outbreak linked to cantaloupe in the U.S. Application of MVLST to MRSA isolates from the Penn State Milton S. Hershey Medical Center (HMC) revealed 27 different MVLST-defined sequence types or Virulence Types ( VTs) among 62 MRSA isolates from nasal swabs of patients entering intensive care units; however, only 9% of these were VT2 (USA 300). In contrast, 21 of 22 (95%) of isolates from infected patients were VT2 (USA300), suggesting that USA300 may have become endemic within HMC. Epidemic clones of both L. monocytogenes and USA300 contain mobile genetic elements (MGEs) such as the comK prophage and ACME, which may play key roles in colonization and local transmission of these epidemic clones in food processing plants and hospitals, respectively. Our results indicate that a combination of MVLST and specific MGE typing may enhance our understanding of their long-term and short-term epidemiology and provide a new tool for accurately tracking and controlling these dangerous pathogens.

Epidemic clones of Listeria monocytogenes and USA300 MRSA possess unique mobile genetic elements and virulence genes sequences that may explain their ability to transmit globally and cause disease

LOMONACO, Sara;
2013-01-01

Abstract

Listeria monocytogenes and USA300 methicillin-resistant Staphylococcus aureus (USA300) are significant Gram-positive pathogens of increasing importance to public health and food and health-care industries worldwide. Severe invasive infections associated with these pathogens are due to a limited number of epidemic clones (ECs), which now cause significant morbidity and mortality around the world. In particular, USA300 is increasingly a major cause of both community- and hospital-acquired (HA) infections. Novel sequence-based subtyping methods have the potential to accurately identify the routes by which these ECs spread to humans, which then allows establishment of more effective intervention strategies. Application of multi-virulence-locus sequence typing (MVLST) to L. monocytogenes revealed 87 different MVLST-defined sequence types or Virulence Types (VTs) among a total of 296 isolates obtained from several outbreaks, sporadic cases, and food and environmental sources worldwide. About 60% of the isolates belonged to one of the seven currently identified ECs of L. monocytogenes, suggesting that ECs can persist and transmit during the intervals between outbreaks. Most recently, ECV was associated with the 2008 listeriosis outbreak linked to deli meats in Canada and ECVI and VII were associated with the 2011 listeriosis outbreak linked to cantaloupe in the U.S. Application of MVLST to MRSA isolates from the Penn State Milton S. Hershey Medical Center (HMC) revealed 27 different MVLST-defined sequence types or Virulence Types ( VTs) among 62 MRSA isolates from nasal swabs of patients entering intensive care units; however, only 9% of these were VT2 (USA 300). In contrast, 21 of 22 (95%) of isolates from infected patients were VT2 (USA300), suggesting that USA300 may have become endemic within HMC. Epidemic clones of both L. monocytogenes and USA300 contain mobile genetic elements (MGEs) such as the comK prophage and ACME, which may play key roles in colonization and local transmission of these epidemic clones in food processing plants and hospitals, respectively. Our results indicate that a combination of MVLST and specific MGE typing may enhance our understanding of their long-term and short-term epidemiology and provide a new tool for accurately tracking and controlling these dangerous pathogens.
2013
asm2013, 113th General Meeting, American Society for Microbiology
Denver, Colorado USA
18-21 Maggio 2013
Proceedings
-
-
Knabel S.J.; Lomonaco S; Verghese B.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/149602
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact