Source: Neuroimaging Clin N Am  |  Posted 6 years ago

By Rabiya Tuma

SAN FRANCISCO, CA -- October 11, 2005 -- Fifteen patients were diagnosed with linezolid-resistant enterococcus in a Tennessee hospital. Of those, only 8 had prior exposure to the drug, suggesting that the remaining 7 cases were the result of patient-to-patient transmission.

Linezolid-resistant enterococcus cases started appearing even before the drug was approved in 2000. However, most of the cases reported in the literature occurred in people who had taken the drug previously, said Rose Devasia, MD, infectious disease fellow, Vanderbilt University, Nashville, Tennessee, who led a case-control study that looked at the hospital outbreak.

Seven (47%) of the infections were due to linezolid-resistant vancomycin-resistant enterococcus; 8 (53%) to linezolid-resistant, vancomycin-sensitive bacteria, reported Dr. Devasia on October 8[^]th[] at the 43[^]rd[] Annual Meeting of the Infectious Diseases Society of America (IDSA).

When the researchers compared the 15 cases with 60 control patients who were infected with linezolid-sensitive enterococcus, they found that linezolid-resistant disease was associated with a significantly higher mortality (40% vs 7%). Linezolid resistance also correlated with a longer hospital stay, with cases having a median of 35 days in the hospital compared with 11 days for controls.

Ten patients (66%) with linezolid-resistant disease had been treated with the antibiotic in the previous 12 months compared with 9 (15%) patients in the control group. Cases were more likely to have had a prior positive methicillin-resistant Staphylococcus aureus (MRSA) culture (66% vs 3%).

Dr. Devasia said that in a point prevalence survey involving 424 patients in the hospital, researchers obtained 388 perirectal cultures, of which 207 (53%) were positive for enterococcus. Fifty-one of those (25%) were vancomycin resistant, while 4 (2%) were resistant to linezolid. They also obtained 393 nares cultures and found that 68 (17%) were positive for S. aureus. MRSA was present in 43 (63%).

"Linezolid-resistant enterococcus is an emerging infection control problem," Dr. Devasia said. The outbreak was controlled using the same procedures that work for vancomycin-resistant disease, she said.

[Presentation title: The First Reported Hospital Outbreak of Linezolid-Resistant Enterococcus: An Infection Control Problem Has Emerged. Abstract 1079]