Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin
A total of 207 Staphylococcus aureus strains, including 105 well-characterized strains with decreased susceptibility to vancomycin (17 vancomycin-intermediate S. aureus [VISA] and 88 heteroresistant VISA [hVISA] strains) and 102 wild-type methicillin-resistant S. aureus (MRSA-WT) strains were tested...
Published in: | Antimicrobial Agents and Chemotherapy |
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Amer Soc Microbiology
2006
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Online Access: | http://repositorio.unifesp.br/handle/11600/28993 https://doi.org/10.1128/AAC.01491-05 |
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ftunivfsaopaulo:oai:repositorio.unifesp.br:11600/28993 2023-05-15T15:41:09+02:00 Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin Sader, Helio S. UNIFESP Fritsche, T. R. Jones, R. N. JMI Labs Universidade Federal de São Paulo (UNIFESP) Tufts Univ 2006-07-01 2330-2336 http://repositorio.unifesp.br/handle/11600/28993 https://doi.org/10.1128/AAC.01491-05 eng eng Amer Soc Microbiology Antimicrobial Agents and Chemotherapy http://dx.doi.org/10.1128/AAC.01491-05 Antimicrobial Agents and Chemotherapy. Washington: Amer Soc Microbiology, v. 50, n. 7, p. 2330-2336, 2006. 0066-4804 http://repositorio.unifesp.br/handle/11600/28993 WOS000238721200008.pdf doi:10.1128/AAC.01491-05 WOS:000238721200008 Acesso aberto Artigo 2006 ftunivfsaopaulo https://doi.org/10.1128/AAC.01491-05 2020-12-09T07:37:06Z A total of 207 Staphylococcus aureus strains, including 105 well-characterized strains with decreased susceptibility to vancomycin (17 vancomycin-intermediate S. aureus [VISA] and 88 heteroresistant VISA [hVISA] strains) and 102 wild-type methicillin-resistant S. aureus (MRSA-WT) strains were tested by reference/standardized broth microdilution and disk diffusion methods, as well as by Etest (AB BIODISK, Solna, Sweden), against daptomycin and vancomycin. the lowest concentration of antimicrobial agent that killed >= 99.9% of the initial inoculum was defined as the minimum bactericidal concentration (MBC) endpoint, and time-kill curves were performed in selected strains to further evaluate bactericidal activity. All MRSA-WT and hVISA strains were inhibited by <= 1 g/ml of daptomycin, while the VISA strains showed slightly higher daptomycin MICs (range, 0.5 to 4 mu g/ml). All daptomycin MBC results were at the MIC or twofold higher. in contrast, 14.7% of MRSA-WT, 69.3% of hVISA, and all VISA strains showed a vancomycin MBC/MIC ratio of :32 or an MBC of 16 mu g/ml (tolerant). the correlation coefficients between broth microdilution and disk diffusion method results were low for daptomycin (0.07) and vancomycin (0.11). Eight (3.8%) strains (all hVISA or VISA) were nonsusceptible to daptomycin by broth microdilution methods but susceptible by the disk diffusion method. for vancomycin, 35 (16.9%) strains were nonsusceptible by broth microdilution methods but susceptible by disk diffusion methods. in conclusion, daptomycin was highly bactericidal against S. aureus strains, and its bactericidal activity was not affected by decreased susceptibility to vancomycin. in contrast, many (one in seven) contemporary MRSA-WT, the majority of hVISA, and all VISA strains showed vancomycin MBC/MIC ratios consistent with tolerance, a predictor of poor clinical response. Disk diffusion tests generally failed to detect strains categorized as nonsusceptible to daptomycin or vancomycin by the reference broth microdilution method or Etest, and reassessment of breakpoints should be immediately attempted for MIC methods suggested as the test of choice. JMI Labs, Beaver Creek Ctr 345, N Liberty, IA 52317 USA Universidade Federal de São Paulo, Div Infect Dis, São Paulo, Brazil Tufts Univ, Sch Med, Boston, MA 02111 USA Universidade Federal de São Paulo, Div Infect Dis, São Paulo, Brazil Web of Science Article in Journal/Newspaper Beaver Creek Universidade Federal de São Paulo (UNIFESP): Repositório Institucional Antimicrobial Agents and Chemotherapy 50 7 2330 2336 |
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Universidade Federal de São Paulo (UNIFESP): Repositório Institucional |
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ftunivfsaopaulo |
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English |
description |
A total of 207 Staphylococcus aureus strains, including 105 well-characterized strains with decreased susceptibility to vancomycin (17 vancomycin-intermediate S. aureus [VISA] and 88 heteroresistant VISA [hVISA] strains) and 102 wild-type methicillin-resistant S. aureus (MRSA-WT) strains were tested by reference/standardized broth microdilution and disk diffusion methods, as well as by Etest (AB BIODISK, Solna, Sweden), against daptomycin and vancomycin. the lowest concentration of antimicrobial agent that killed >= 99.9% of the initial inoculum was defined as the minimum bactericidal concentration (MBC) endpoint, and time-kill curves were performed in selected strains to further evaluate bactericidal activity. All MRSA-WT and hVISA strains were inhibited by <= 1 g/ml of daptomycin, while the VISA strains showed slightly higher daptomycin MICs (range, 0.5 to 4 mu g/ml). All daptomycin MBC results were at the MIC or twofold higher. in contrast, 14.7% of MRSA-WT, 69.3% of hVISA, and all VISA strains showed a vancomycin MBC/MIC ratio of :32 or an MBC of 16 mu g/ml (tolerant). the correlation coefficients between broth microdilution and disk diffusion method results were low for daptomycin (0.07) and vancomycin (0.11). Eight (3.8%) strains (all hVISA or VISA) were nonsusceptible to daptomycin by broth microdilution methods but susceptible by the disk diffusion method. for vancomycin, 35 (16.9%) strains were nonsusceptible by broth microdilution methods but susceptible by disk diffusion methods. in conclusion, daptomycin was highly bactericidal against S. aureus strains, and its bactericidal activity was not affected by decreased susceptibility to vancomycin. in contrast, many (one in seven) contemporary MRSA-WT, the majority of hVISA, and all VISA strains showed vancomycin MBC/MIC ratios consistent with tolerance, a predictor of poor clinical response. Disk diffusion tests generally failed to detect strains categorized as nonsusceptible to daptomycin or vancomycin by the reference broth microdilution method or Etest, and reassessment of breakpoints should be immediately attempted for MIC methods suggested as the test of choice. JMI Labs, Beaver Creek Ctr 345, N Liberty, IA 52317 USA Universidade Federal de São Paulo, Div Infect Dis, São Paulo, Brazil Tufts Univ, Sch Med, Boston, MA 02111 USA Universidade Federal de São Paulo, Div Infect Dis, São Paulo, Brazil Web of Science |
author2 |
JMI Labs Universidade Federal de São Paulo (UNIFESP) Tufts Univ |
format |
Article in Journal/Newspaper |
author |
Sader, Helio S. UNIFESP Fritsche, T. R. Jones, R. N. |
spellingShingle |
Sader, Helio S. UNIFESP Fritsche, T. R. Jones, R. N. Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin |
author_facet |
Sader, Helio S. UNIFESP Fritsche, T. R. Jones, R. N. |
author_sort |
Sader, Helio S. UNIFESP |
title |
Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin |
title_short |
Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin |
title_full |
Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin |
title_fullStr |
Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin |
title_full_unstemmed |
Daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of Staphylococcus aureus strains with decreased susceptibility to vancomycin |
title_sort |
daptomycin bactericidal activity and correlation between disk and broth microdilution method results in testing of staphylococcus aureus strains with decreased susceptibility to vancomycin |
publisher |
Amer Soc Microbiology |
publishDate |
2006 |
url |
http://repositorio.unifesp.br/handle/11600/28993 https://doi.org/10.1128/AAC.01491-05 |
genre |
Beaver Creek |
genre_facet |
Beaver Creek |
op_relation |
Antimicrobial Agents and Chemotherapy http://dx.doi.org/10.1128/AAC.01491-05 Antimicrobial Agents and Chemotherapy. Washington: Amer Soc Microbiology, v. 50, n. 7, p. 2330-2336, 2006. 0066-4804 http://repositorio.unifesp.br/handle/11600/28993 WOS000238721200008.pdf doi:10.1128/AAC.01491-05 WOS:000238721200008 |
op_rights |
Acesso aberto |
op_doi |
https://doi.org/10.1128/AAC.01491-05 |
container_title |
Antimicrobial Agents and Chemotherapy |
container_volume |
50 |
container_issue |
7 |
container_start_page |
2330 |
op_container_end_page |
2336 |
_version_ |
1766374016029818880 |