Disk with high oxacillin content discriminates between methicillin-resistant and borderline methicillin-susceptible Staphylococcus aureus strains in disk diffusion assays using a low salt concentration
(1999) In Journal of Clinical Microbiology 37(6). p.2047-2050- Abstract
- A separation between mecA+ strains of Staphylococcus aureus and strains lacking mecA was achieved by the disk diffusion assay and the agar dilution method, utilizing disks containing 5 microg of oxacillin and inocula of approximately 5 x 10(5) CFU/spot, respectively, provided that agar with 0 to 0.5% NaCl and incubation at 30 degrees C were employed. The 5-microg oxacillin disks clearly discriminated between borderline methicillin-susceptible and mecA+ strains. The oxacillin MICs were more affected by the inoculum density and salt concentration than were the methicillin MICs, and oxacillin MICs of 4 to 16 microg/ml were obtained for strains lacking mecA. Significantly higher levels of beta-lactamase production and reduced oxacillin... (More)
- A separation between mecA+ strains of Staphylococcus aureus and strains lacking mecA was achieved by the disk diffusion assay and the agar dilution method, utilizing disks containing 5 microg of oxacillin and inocula of approximately 5 x 10(5) CFU/spot, respectively, provided that agar with 0 to 0.5% NaCl and incubation at 30 degrees C were employed. The 5-microg oxacillin disks clearly discriminated between borderline methicillin-susceptible and mecA+ strains. The oxacillin MICs were more affected by the inoculum density and salt concentration than were the methicillin MICs, and oxacillin MICs of 4 to 16 microg/ml were obtained for strains lacking mecA. Significantly higher levels of beta-lactamase production and reduced oxacillin susceptibilities were recorded for strains lacking mecA, in particular strains of phage group V, when agar with >/=2% NaCl was used than when agar with 0 to 0.5% NaCl was employed. The results indicate that the borderline methicillin-susceptible phenotype is a salt-dependent in vitro phenomenon of questionable clinical relevance. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1114995
- author
- Petersson, Ann Cathrine ; Kamme, Carl and Miörner, Håkan LU
- organization
- publishing date
- 1999
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Clinical Microbiology
- volume
- 37
- issue
- 6
- pages
- 2047 - 2050
- publisher
- American Society for Microbiology
- external identifiers
-
- pmid:10325377
- scopus:0032911958
- ISSN
- 1098-660X
- language
- English
- LU publication?
- yes
- id
- 97ec6765-c5af-4cf7-8dc8-5b777d638a2f (old id 1114995)
- alternative location
- http://jcm.highwire.org/cgi/content/full/37/6/2047
- date added to LUP
- 2016-04-01 17:12:45
- date last changed
- 2022-01-29 01:06:26
@article{97ec6765-c5af-4cf7-8dc8-5b777d638a2f,
abstract = {{A separation between mecA+ strains of Staphylococcus aureus and strains lacking mecA was achieved by the disk diffusion assay and the agar dilution method, utilizing disks containing 5 microg of oxacillin and inocula of approximately 5 x 10(5) CFU/spot, respectively, provided that agar with 0 to 0.5% NaCl and incubation at 30 degrees C were employed. The 5-microg oxacillin disks clearly discriminated between borderline methicillin-susceptible and mecA+ strains. The oxacillin MICs were more affected by the inoculum density and salt concentration than were the methicillin MICs, and oxacillin MICs of 4 to 16 microg/ml were obtained for strains lacking mecA. Significantly higher levels of beta-lactamase production and reduced oxacillin susceptibilities were recorded for strains lacking mecA, in particular strains of phage group V, when agar with >/=2% NaCl was used than when agar with 0 to 0.5% NaCl was employed. The results indicate that the borderline methicillin-susceptible phenotype is a salt-dependent in vitro phenomenon of questionable clinical relevance.}},
author = {{Petersson, Ann Cathrine and Kamme, Carl and Miörner, Håkan}},
issn = {{1098-660X}},
language = {{eng}},
number = {{6}},
pages = {{2047--2050}},
publisher = {{American Society for Microbiology}},
series = {{Journal of Clinical Microbiology}},
title = {{Disk with high oxacillin content discriminates between methicillin-resistant and borderline methicillin-susceptible Staphylococcus aureus strains in disk diffusion assays using a low salt concentration}},
url = {{http://jcm.highwire.org/cgi/content/full/37/6/2047}},
volume = {{37}},
year = {{1999}},
}