Biomaterial Database

Community-acquired methicillin-resistant Staphylococcus aureus: the role of Panton-Valentine leukocidin. 2007

Susan Boyle-Vavra, and Robert S Daum

Department of Pediatrics, Section of Infectious Diseases, University of Chicago, Chicago, IL 60637, USA. sboyle@peds.bsd.uchicago.edu

Community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) infection among individuals without healthcare-associated (HA) risk factors was first recognized about a decade ago. It has now emerged as an epidemic that is responsible for rapidly progressive, fatal diseases including necrotizing pneumonia, severe sepsis and necrotizing fasciitis. Unlike HA-MRSA, CA-MRSA are usually pan-susceptible to non-beta-lactam antimicrobials. In addition to novel methicillin resistance genetic cassettes, many CA-MRSA harbor a phage harboring Panton-Valentine Leukocidin (PVL) genes and some data support the idea that PVL is responsible at least in part for the increased virulence of CA-MRSA. The tight association between the novel methicillin resistance cassettes and PVL phage cannot be explained, as they integrate into distinct sites on the S. aureus chromosome. This paper presents the evidence that CA-MRSA isolates are distinct strains emerging de novo from CA-methicillin susceptible isolates rather than from HA-MRSA isolates that have escaped from the hospital setting and that these novel CA-MRSA isolates may be more virulent than HA-MRSA. The second aim is to outline the progress in understanding the role of PVL in CA-MRSA pathogenesis.

UI	MeSH Term	Description	Entries
D007956	Leukocidins	Pore forming proteins originally discovered for toxic activity to LEUKOCYTES. They are EXOTOXINS produced by some pathogenic STAPHYLOCOCCUS and STREPTOCOCCUS that destroy leukocytes by lysis of the cytoplasmic granules and are partially responsible for the pathogenicity of the organisms.	Leucocidin,Leukocidin,Leukocidin Proteins,Proteins, Leukocidin
D005098	Exotoxins	Toxins produced, especially by bacterial or fungal cells, and released into the culture medium or environment.	Exotoxin
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001427	Bacterial Toxins	Toxic substances formed in or elaborated by bacteria; they are usually proteins with high molecular weight and antigenicity; some are used as antibiotics and some to skin test for the presence of or susceptibility to certain diseases.	Bacterial Toxin,Toxins, Bacterial,Toxin, Bacterial
D013203	Staphylococcal Infections	Infections with bacteria of the genus STAPHYLOCOCCUS.	Infections, Staphylococcal,Staphylococcus aureus Infection,Staphylococcal Infection,Staphylococcus aureus Infections
D013211	Staphylococcus aureus	Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
D014774	Virulence	The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.	Pathogenicity
D016106	Methicillin Resistance	Non-susceptibility of a microbe to the action of METHICILLIN, a semi-synthetic penicillin derivative.	Methicillin-Resistant,Methicillin Resistant,Resistance, Methicillin
D017714	Community-Acquired Infections	Any infection acquired in the community, that is, contrasted with those acquired in a health care facility (CROSS INFECTION). An infection would be classified as community-acquired if the patient had not recently been in a health care facility or been in contact with someone who had been recently in a health care facility.	Community Acquired Infection,Community-Acquired Infection,Infections, Community-Acquired,Acquired Infection, Community,Acquired Infections, Community,Community Acquired Infections,Infection, Community Acquired,Infection, Community-Acquired,Infections, Community Acquired