Shiloh
Editor, Senior Moderator
Source: http://www.medpagetoday.com/MeetingCoverage/ICAAC/15955
Medical News from
ICAAC: Interscience Conference on Antimicrobial Agents and Chemotherapy Meeting
ICAAC: MRSA Heart Infections Growing in Inner Cities
By Michael Smith, North American Correspondent, MedPage Today
Published: September 14, 2009
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.
Action Points
* Explain to interested patients that Staphylococcus aureus is an important cause of infections in the heart.
* Note that this single-institution study suggests that in the inner city such cases are now predominately caused by methicillin-resistant Staphylococcus aureus (MRSA), which is much more difficult to treat than its drug-susceptible counterpart.
* Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
SAN FRANCISCO -- Methicillin-resistant Staphylococcus aureus (MRSA) is becoming the leading cause of staph-associated infective endocarditis in some areas, a researcher said here.
Over an eight-year period, starting in 2000, the proportion of such cases caused by MRSA went from 25% to 85% in an inner city hospital, according to Graeme Forrest, MBBS, of Oregon Health and Science University.
The rise of MRSA cases at the University of Maryland in Baltimore -- where Forrest and colleagues carried out the study -- was paralleled by a drop in cases caused by drug-susceptible S. aureus, he said at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
The lack of proven antimicrobial treatments suggests an "urgent need" for new therapies, Forrest said, as well as a need to evaluate early surgery in such patients.
Forrest said the study only has data from a single institution, but he suspects that situation is the same in other inner city hospitals, where social conditions -- including issues such as injection drug use and over-crowding -- have increased rates of community-acquired MRSA.
For the study, the researchers looked at 1,356 episodes of proven or probable infective endocarditis from 740 patients from 2000 through 2007.
Of those, 425 patients met criteria for S. aureus endocarditis, with MRSA accounting for 286 (or 67%) of all such cases and susceptible S. aureus for 139 (or 33%).
The increase in MRSA cases -- which went from from 25 % of S. aureus cases to 85% over the time period -- was significant at P=0.005, Forrest said.
In 2000, he and colleagues found, the incidence of MRSA infective endocarditis was 22%, but it climbed to 58% in 2007. At the same time, susceptible S. aureus fell from 55% in 2000 to under 10% in 2007. The changes were significant at P=0.03.
The turning point, Forrest said, came in 2002 for reasons that are not clear, but probably have to do with the prevalence of MRSA in the community.
The change had a significant effect on mortality, he said: Survival was 90% for those with drug-susceptible infections, compared with 79% for those with MRSA (P=0.004).
The finding "makes sense ... as there have been reports that infective endocarditis caused by MRSA is increasing among IV drug users," said Lindsay Grayson, MD, of the Austin Hospital in Melbourne, Australia. Grayson, one of the meeting's program co-chairs, was not part of the research.
But, he added, the issue is likely limited to the inner cities. "Outside of that setting I am not aware of any reports" that MRSA-associated endocarditis is increasing.
The study was not funded. Forrest did not report any potential conflicts.
Primary source: Interscience Conference on Antimicrobial Agents and Chemotherapy
Source reference:
Forrest GN et al. "Changes in Susceptibility of Staphylococcus aureus Endocarditis since 2000" ICAAC 2009; Abstract K-264.
Medical News from
ICAAC: Interscience Conference on Antimicrobial Agents and Chemotherapy Meeting
ICAAC: MRSA Heart Infections Growing in Inner Cities
By Michael Smith, North American Correspondent, MedPage Today
Published: September 14, 2009
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.
Action Points
* Explain to interested patients that Staphylococcus aureus is an important cause of infections in the heart.
* Note that this single-institution study suggests that in the inner city such cases are now predominately caused by methicillin-resistant Staphylococcus aureus (MRSA), which is much more difficult to treat than its drug-susceptible counterpart.
* Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
SAN FRANCISCO -- Methicillin-resistant Staphylococcus aureus (MRSA) is becoming the leading cause of staph-associated infective endocarditis in some areas, a researcher said here.
Over an eight-year period, starting in 2000, the proportion of such cases caused by MRSA went from 25% to 85% in an inner city hospital, according to Graeme Forrest, MBBS, of Oregon Health and Science University.
The rise of MRSA cases at the University of Maryland in Baltimore -- where Forrest and colleagues carried out the study -- was paralleled by a drop in cases caused by drug-susceptible S. aureus, he said at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
The lack of proven antimicrobial treatments suggests an "urgent need" for new therapies, Forrest said, as well as a need to evaluate early surgery in such patients.
Forrest said the study only has data from a single institution, but he suspects that situation is the same in other inner city hospitals, where social conditions -- including issues such as injection drug use and over-crowding -- have increased rates of community-acquired MRSA.
For the study, the researchers looked at 1,356 episodes of proven or probable infective endocarditis from 740 patients from 2000 through 2007.
Of those, 425 patients met criteria for S. aureus endocarditis, with MRSA accounting for 286 (or 67%) of all such cases and susceptible S. aureus for 139 (or 33%).
The increase in MRSA cases -- which went from from 25 % of S. aureus cases to 85% over the time period -- was significant at P=0.005, Forrest said.
In 2000, he and colleagues found, the incidence of MRSA infective endocarditis was 22%, but it climbed to 58% in 2007. At the same time, susceptible S. aureus fell from 55% in 2000 to under 10% in 2007. The changes were significant at P=0.03.
The turning point, Forrest said, came in 2002 for reasons that are not clear, but probably have to do with the prevalence of MRSA in the community.
The change had a significant effect on mortality, he said: Survival was 90% for those with drug-susceptible infections, compared with 79% for those with MRSA (P=0.004).
The finding "makes sense ... as there have been reports that infective endocarditis caused by MRSA is increasing among IV drug users," said Lindsay Grayson, MD, of the Austin Hospital in Melbourne, Australia. Grayson, one of the meeting's program co-chairs, was not part of the research.
But, he added, the issue is likely limited to the inner cities. "Outside of that setting I am not aware of any reports" that MRSA-associated endocarditis is increasing.
The study was not funded. Forrest did not report any potential conflicts.
Primary source: Interscience Conference on Antimicrobial Agents and Chemotherapy
Source reference:
Forrest GN et al. "Changes in Susceptibility of Staphylococcus aureus Endocarditis since 2000" ICAAC 2009; Abstract K-264.