Skip to main page content

• HOME
• Current Issue
• Archive
• Alerts
• About ASM
• Contact us
• Tech Support
• Journals.ASM.org

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gqada, Z. Articles by Eliopoulos, G. M. Search for Related Content PubMed PubMed Citation Articles by Gqada, Z. Articles by Eliopoulos, G. M.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, July 2008, p. 2471-2472, Vol. 46, No. 7
0095-1137/08/$08.00+0     doi:10.1128/JCM.00519-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

LETTER TO THE EDITOR

Clinical Rationale for Treatment of Endocarditis Caused by Methicillin-Susceptible Staphylococcus aureus Developing Nonsusceptibility to Daptomycin

Top LETTER REFERENCES LETTER{nbsp} REFERENCE{nbsp}

 
A recent case report by Sakoulas et al. demonstrated acquired daptomycin (lipopeptide) resistance in an immune-competent adult patient with native valve endocarditis due to methicillin-susceptible Staphylococcus aureus (MSSA) (8). Daptomycin resistance developed following exposure to levofloxacin and vancomycin prior to daptomycin treatment. The observation that vancomycin exposure may induce resistance mechanisms in staphylococcal species is consistent with another recent report in which vancomycin exposure was accompanied by decreased expression of agr, resulting in resistance to platelet microbicidal proteins (6). It is believed that daptomycin's mechanism of action involves functional disruption of the bacterial plasma membrane (1, 4, 7).

However, what is most striking about the article is the impression that the patient was not managed optimally. Nafcillin/cloxacillin (with/without an aminoglycoside) would be widely accepted as the drug of choice to treat MSSA native valve endocarditis; comparative studies have confirmed cloxacillin/nafcillin to have superior efficacy to vancomycin in patients with MSSA bacteremia (2, 5). Despite confirmation that the offending organism was methicillin sensitive, the patient was first managed on levofloxacin and then switched to vancomycin. Following a poor response to vancomycin, the patient was placed on nafcillin for a very brief period (3 days only), before switching to daptomycin monotherapy. The clinical rationale applied is not explained in the methods section nor taken up in the discussion.

Resistance to daptomycin was documented after 6 to 7 days of treatment. Only after 17 days of antibiotic treatment did the patient receive a prolonged course of nafcillin and gentamicin. Unfortunately, the patient's mitral valve was destroyed by the time infection was brought under control and he underwent successful valve replacement, which remains a suboptimal outcome. It would be interesting to know why first vancomycin and then daptomycin were regarded as the drugs of choice to treat a patient with MSSA bacteremia. According to the clinical trial (3) of daptomycin versus standard therapy of S. aureus bacteremia and right-sided endocarditis referred to in the report by Sakoulas et al., success rates favored daptomycin over vancomycin among patients with methicillin-resistant S. aureus but were higher for MSSA infection treated with an antistaphylococcal penicillin (nafcillin, oxacillin, or flucloxacillin) compared to daptomycin.

Despite the fact that one of the authors is affiliated with the company producing daptomycin, no conflict of interest was declared. We believe it is essential that every publication should include a conflict of interest statement. This article demonstrates the importance of ensuring transparency in order to protect the best interests of our patients.

Top LETTER REFERENCES LETTER{nbsp} REFERENCE{nbsp}

 

1
1. Alborn, W. E., Jr., N. E. Allen, and D. A. Preston. 1991. Daptomycin disrupts membrane potential in growing Staphylococcus aureus. Antimicrob. Agents Chemother. 35:2282-2287.[Abstract/Free Full Text]
2
2. Chang, F. Y., J. E. Peacock, Jr., D. M. Musher, P. Triplett, B. B. MacDonald, J. M. Mylotte, A. O'Donnell, M. M. Wagener, and V. L. Yu. 2003. Staphylococcus aureus bacteremia recurrence and the impact of antibiotic treatment in a prospective multicenter study. Medicine 82:333-339.[Medline]
3
3. Fowler, V. G., Jr., H. W. Boucher, and G. R. Corey. 2006. Daptomycin versus standard therapy for bacteraemia and endocarditis caused by Staphylococcus aureus. N. Engl. J. Med. 355:653-665.[Abstract/Free Full Text]
4
4. Hancock, R. E. W. 2005. Mechanisms of action of newer antibiotics for gram-positive pathogens. Lancet Infect. Dis. 5:209-218.[CrossRef][Medline]
5
5. Lodise, T. P., Jr., P. S. McKinnon, D. P. Levine, and M. J. Rybak. 2007. Impact of empirical-therapy selection on outcomes of intravenous drug users with infective endocarditis caused by methicillin-susceptible Staphylococcus aureus. Antimicrob. Agents Chemother. 51:3731-3733.[Abstract/Free Full Text]
6
6. Moise, P. A., D. S. Smyth, N. El-Fawal, and D. A. Robinson. 2008. Microbiological effects of prior vancomycin use in patients with methicillin-resistant Staphylococcus aureus bacteraemia. J. Antimicrob. Chemother. 61:85-90.[Abstract/Free Full Text]
7
7. Thorne, G. M., and J. Alder. 2002. Daptomycin: a novel lipopeptide antibiotic. Clin. Microbiol. Newsl. 24:33-40.[CrossRef]
8
8. Sakoulas, G., W. Rose, M. J. Rybak, S. Pillai, J. Alder, R. C. Moellering, Jr., and G. M. Eliopoulos. 2008. Evaluation of endocarditis caused by methicillin-susceptible Staphylococcus aureus developing nonsusceptibility to daptomycin. J. Clin. Microbiol. 46:220-224.[Abstract/Free Full Text]

						Zukile Gqada* Department of Pathology, Division of Medical Microbiology Faculty of Health Sciences Stellenbosch University and the NHLS Tygerberg Hospital Cape Town, South Africa Ben Marais Department of Paediatrics and Child Health Faculty of Health Sciences Stellenbosch University Tygerberg Hospital Cape Town, South Africa Elizabeth Wasserman Colleen Bamford Heidi Orth Department of Pathology, Division of Medical Microbiology Faculty of Health Sciences Stellenbosch University and the NHLS Tygerberg Hospital Cape Town, South Africa
						* Phone: 27 21 938 4032 Fax: 27 21 938 4005 E-mail: zgqada{at}sun.ac.za

Authors' Reply

Top LETTER REFERENCES LETTER{nbsp} REFERENCE{nbsp}

 
We appreciate the interest raised in our article "Evaluation of endocarditis caused by methicillin-susceptible Staphylococcus aureus developing nonsusceptibility to vancomycin" (1). A discussion of optimal medical management of endocarditis was not the purpose of our paper. Details regarding antibiotic exposure were provided only to describe the exposure background of the sequential isolates studied in vitro, which was the focus of the paper. Nonessential clinical details were omitted because this was not intended as a "case report."

In response to the authors' queries, levofloxacin and vancomycin had been administered empirically prior to knowledge of the patient's diagnosis. Nafcillin was indeed used once MSSA bacteria were identified; this was switched to daptomycin in response to persistently positive blood cultures on nafcillin.

We support not only the principle of author transparency, but also the duty, as exemplified by our paper, to report any limitations or other cautionary observations regarding use of antibiotics to treat serious infections. All authors fully declared to the journal any relevant financial relationship when the paper was submitted. These are as follows. G.S. was a consultant for Cubist Pharmaceuticals and Pfizer; had a research grant from Cubist Pharmaceuticals and Pfizer; and was a member of the Speakers Bureau for Cubist Pharmaceuticals, Pfizer, and Wyeth. W.R. had no relevant financial relationships. M.J.R. was a consultant for Cubist Pharmaceuticals, Pfizer, Johnson & Johnson, Astellas, Cerexia/Forrest, and Wyeth; had research grants from Cubist Pharmaceuticals, Pfizer, Johnson & Johnson, Astellas, and Cerexia/Forrest; and was a member of the Speakers Bureau for Cubist Pharmaceuticals, Pfizer, Ortho-McNeil/Johnson & Johnson, and Wyeth. S.P. had no relevant financial relationships. J.A. was employed by Cubist Pharmaceuticals at the time of study and publication. R.C.M. was a consultant to Cubist Pharmaceuticals and Ortho-McNeil/Johnson & Johnson. G.M.E. was a consultant to Cubist Pharmaceuticals and had a research grant from Cubist Pharmaceuticals.

Top LETTER REFERENCES LETTER{nbsp} REFERENCE{nbsp}

 

1
1. Sakoulas, G., W. Rose, M. J. Rybak, S. Pillai, J. Alder, R. C. Moellering, Jr., and G. M. Eliopoulos. 2008. Evaluation of endocarditis caused by methicillin-susceptible Staphylococcus aureus developing nonsusceptibility to daptomycin. J. Clin. Microbiol. 46:220-224.[Abstract/Free Full Text]

						George Sakoulas* Department of Medicine Division of Infectious Diseases New York Medical College and Westchester Medical Center Munger Pavilion, Room 245 Valhalla, New York 10595 Warren Rose Michael J. Rybak Anti-Infective Research Laboratory Eugene Applebaum College of Pharmacy and Health Sciences Wayne State University Detroit, Michigan 48201 Satish Pillai Department of Infectious Disease Cleveland Clinic Foundation Cleveland, Ohio 44195 Jeff Alder Cubist Pharmaceuticals Lexington, Massachusetts 02421 Robert C. Moellering Jr. George M. Eliopoulos Department of Medicine Beth Israel Deaconess Medical Center and Harvard Medical School Boston, Massachusetts 02215
						* Phone: (914) 594-4974 Fax: (845) 361-1156 E-mail: george_sakoulas{at}nymc.edu

---

Journal of Clinical Microbiology, July 2008, p. 2471-2472, Vol. 46, No. 7
0095-1137/08/$08.00+0     doi:10.1128/JCM.00519-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gqada, Z. Articles by Eliopoulos, G. M. Search for Related Content PubMed PubMed Citation Articles by Gqada, Z. Articles by Eliopoulos, G. M.