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Evaluation of penicillin G susceptibility testing methods for Staphylococcus lugdunensis

Hagstrand Aldman, Malin LU orcid and Påhlman, Lisa I. LU (2020) In The Journal of antimicrobial chemotherapy 75(5). p.1206-1211
Abstract

BACKGROUND: Staphylococcus lugdunensis belongs to the CoNS group, but is regarded to be more virulent than most other CoNS. It is also remarkably susceptible to antibiotics, including penicillin G. OBJECTIVES: To evaluate different methods for penicillin susceptibility testing, to assess penicillin susceptibility rates among S. lugdunensis and to describe the clinical presentation including antibiotic treatment. METHODS: Clinical isolates of S. lugdunensis were tested for penicillin susceptibility using disc diffusion according to CLSI (10 U disc) and EUCAST (1 U disc), assessment of zone-edge appearance, nitrocefin test and Etest for MIC determination. PCR of the blaZ gene was used as a reference method. RESULTS: Of the 112 isolates... (More)

BACKGROUND: Staphylococcus lugdunensis belongs to the CoNS group, but is regarded to be more virulent than most other CoNS. It is also remarkably susceptible to antibiotics, including penicillin G. OBJECTIVES: To evaluate different methods for penicillin susceptibility testing, to assess penicillin susceptibility rates among S. lugdunensis and to describe the clinical presentation including antibiotic treatment. METHODS: Clinical isolates of S. lugdunensis were tested for penicillin susceptibility using disc diffusion according to CLSI (10 U disc) and EUCAST (1 U disc), assessment of zone-edge appearance, nitrocefin test and Etest for MIC determination. PCR of the blaZ gene was used as a reference method. RESULTS: Of the 112 isolates included in the study, 67% were susceptible to penicillin G according to blaZ PCR. The EUCAST disc diffusion test had 100% sensitivity, whereas the CLSI method had one very major error with a false-susceptible isolate. When zone-edge appearance was included in the assessment, the false-susceptible isolate was correctly classified as resistant. Foreign-body infection was the most common focus of infection, affecting 49% of the participants. Only 4% of the patients were treated with penicillin G. CONCLUSIONS: Penicillin susceptibility is common in S. lugdunensis and the disc diffusion method according to EUCAST had a higher sensitivity than that of CLSI. Assessment of zone-edge appearance could increase the sensitivity of the disc diffusion test. Penicillin susceptibility testing and treatment should be considered in S. lugdunensis infections.

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Contribution to journal
publication status
published
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in
The Journal of antimicrobial chemotherapy
volume
75
issue
5
pages
6 pages
publisher
Oxford University Press
external identifiers
  • pmid:32016343
  • scopus:85084028220
ISSN
1460-2091
DOI
10.1093/jac/dkaa004
language
English
LU publication?
yes
id
7fd253ac-249d-4ea8-8347-205d7445ed60
date added to LUP
2020-05-18 14:19:13
date last changed
2024-07-24 18:59:03
@article{7fd253ac-249d-4ea8-8347-205d7445ed60,
  abstract     = {{<p>BACKGROUND: Staphylococcus lugdunensis belongs to the CoNS group, but is regarded to be more virulent than most other CoNS. It is also remarkably susceptible to antibiotics, including penicillin G. OBJECTIVES: To evaluate different methods for penicillin susceptibility testing, to assess penicillin susceptibility rates among S. lugdunensis and to describe the clinical presentation including antibiotic treatment. METHODS: Clinical isolates of S. lugdunensis were tested for penicillin susceptibility using disc diffusion according to CLSI (10 U disc) and EUCAST (1 U disc), assessment of zone-edge appearance, nitrocefin test and Etest for MIC determination. PCR of the blaZ gene was used as a reference method. RESULTS: Of the 112 isolates included in the study, 67% were susceptible to penicillin G according to blaZ PCR. The EUCAST disc diffusion test had 100% sensitivity, whereas the CLSI method had one very major error with a false-susceptible isolate. When zone-edge appearance was included in the assessment, the false-susceptible isolate was correctly classified as resistant. Foreign-body infection was the most common focus of infection, affecting 49% of the participants. Only 4% of the patients were treated with penicillin G. CONCLUSIONS: Penicillin susceptibility is common in S. lugdunensis and the disc diffusion method according to EUCAST had a higher sensitivity than that of CLSI. Assessment of zone-edge appearance could increase the sensitivity of the disc diffusion test. Penicillin susceptibility testing and treatment should be considered in S. lugdunensis infections.</p>}},
  author       = {{Hagstrand Aldman, Malin and Påhlman, Lisa I.}},
  issn         = {{1460-2091}},
  language     = {{eng}},
  number       = {{5}},
  pages        = {{1206--1211}},
  publisher    = {{Oxford University Press}},
  series       = {{The Journal of antimicrobial chemotherapy}},
  title        = {{Evaluation of penicillin G susceptibility testing methods for Staphylococcus lugdunensis}},
  url          = {{http://dx.doi.org/10.1093/jac/dkaa004}},
  doi          = {{10.1093/jac/dkaa004}},
  volume       = {{75}},
  year         = {{2020}},
}