A Molecular Epidemiological Analysis of 2Staphylococcus aureusClonal Types Colonizing and Infecting Patients with AIDS

Abstract

This study demonstrates a sustained high rate of S. aureus carriage and infection. It demonstrates the capacity of unique methicillin-resistant S. aureus clones with an established linkage to earlier outbreaks of methicillin-resistant S. aureus, as well as to human immunodeficiency virus--infected subjects, to persist in this residential setting. It also illustrates the apparent genetic instability or transmissibility of the staphylococcal chromosomal cassette mec type IV element.

Origins and Evolution of Methicillin-ResistantStaphylococcus aureusClonal Lineages

“…ST25 MSSA has been present for over three decades in the hospital and in the community (although it is PVL negative) (15,16; this study). ST25 is not a favorable genetic background for the constitutive expression of a plasmid-introduced mecA (27) but has recently been reported to be a highly transmissible clone associated with colonization and infection in the niche of AIDS patients with a history of drug use (20).…”

Unusually High Prevalence of Nosocomial Panton-Valentine Leukocidin-Positive Staphylococcus aureus Isolates in Cape Verde Islands

“…Clones ST 1 and ST 30 PVL ϩ have been described as the most frequent community-acquired MRSA clones in the United States and Oceania, respectively (31). ST 121 has been detected among isolates carrying PVL genes in England and Wales (14), and ST 25 was recently reported as a highly transmissible clone associated with colonization and infection in the niche of AIDS-infected patients with a history of drug use (11). It is known that the genes that encode PVL are carried by different temperate phages and that S. aureus strains are usually lysogenized by a phage(s) (22).…”

Incidence and Persistence of Staphylococcus aureus Nasal Colonization in a Community Sample of HIV-Infected and -Uninfected Drug Users

“…Recently documented increases in community-associated methicillinresistant S. aureus (MRSA) infection suggest that there is already a reservoir of methicillin-resistant strains [1][2][3]. The use of antimicrobials as both prophylactic and therapeutic agents for opportunistic infections in HIV-infected individuals and for cutaneous infections in injection drug users may increase the likelihood of nasal carriage of antimicrobial-resistant S. aureus [4] and suggests that these groups may be "hidden" contributors to a community-based reservoir.We prospectively observed a subsample of participants from a large, well-characterized, community-based sample of current …”

“…In terms of possible underlying mechanisms of S. aureus transmission, colonization risk may be environmental, such as a high background prevalence of S. aureus (e.g., high levels of colonization among the health care providers of HIV-infected individuals [4,9] and unhygienic drug-use environments [12,13]). Alternatively, transmission risk could be related to the social networks of HIV-infected individuals (e.g., HIV-infected individuals may socialize in the community, which could provide greater opportunity for exposure to disease [14]).…”