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Penicillin-susceptible Staphylococcus aureus : susceptibility testing, resistance rates and outcome of infection

Hagstrand Aldman, Malin; Skovby, Annette and I. Påhlman, Lisa LU (2017) In Infectious Diseases 49(6). p.454-460
Abstract

Background: Staphylococcus aureus (SA) is an important human pathogen that causes both superficial and invasive infections. Penicillin is now rarely used in the treatment of SA infections due to widespread resistance and a concern about the accuracy of existing methods for penicillin susceptibility testing. The aims of the present study were to determine the frequency of penicillin-susceptible SA isolates from blood and wound cultures in Lund, Sweden, and to evaluate methods for penicillin testing in SA. We also wanted to investigate if penicillin-susceptible isolates are associated with higher mortality. Methods: Hundred blood culture isolates collected 2008/2009, 140 blood culture isolates from 2014/2015, and 141 superficial wound... (More)

Background: Staphylococcus aureus (SA) is an important human pathogen that causes both superficial and invasive infections. Penicillin is now rarely used in the treatment of SA infections due to widespread resistance and a concern about the accuracy of existing methods for penicillin susceptibility testing. The aims of the present study were to determine the frequency of penicillin-susceptible SA isolates from blood and wound cultures in Lund, Sweden, and to evaluate methods for penicillin testing in SA. We also wanted to investigate if penicillin-susceptible isolates are associated with higher mortality. Methods: Hundred blood culture isolates collected 2008/2009, 140 blood culture isolates from 2014/2015, and 141 superficial wound culture strains from 2015 were examined. Penicillin susceptibility was tested with disk diffusion according to EUCAST guidelines, and results were confirmed with a cloverleaf assay and PCR amplification of the BlaZ gene. Patient data for all bacteraemia cases were extracted from medical records. Results: The disk diffusion method with assessment of both zone size and zone edge appearance had high accuracy in our study. About 57% of bacteraemia isolates from 2008/2009 were sensitive to penicillin compared to 29% in 2014/2015 (p < .0001). In superficial wound cultures, 21% were penicillin susceptible. There was no difference in co-morbidity or mortality rates between patients with penicillin resistant and penicillin sensitive SA bacteraemia. Conclusion: Disk-diffusion is a simple and reliable method to detect penicillin resistance in SA, and susceptibility rates are significant. Penicillin has many theoretical advantages and should be considered in the treatment of SA bacteraemia when susceptible.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
disk diffusion, mortality, penicillin susceptibility, Staphylococcus aureus
in
Infectious Diseases
volume
49
issue
6
pages
7 pages
publisher
Informa Healthcare
external identifiers
  • scopus:85011292144
  • wos:000399496500003
ISSN
2374-4235
DOI
10.1080/23744235.2017.1280617
language
English
LU publication?
yes
id
ec294604-11ec-4ee9-ba2a-02ac01308f6c
date added to LUP
2017-02-14 14:20:39
date last changed
2018-01-07 11:49:44
@article{ec294604-11ec-4ee9-ba2a-02ac01308f6c,
  abstract     = {<p>Background: Staphylococcus aureus (SA) is an important human pathogen that causes both superficial and invasive infections. Penicillin is now rarely used in the treatment of SA infections due to widespread resistance and a concern about the accuracy of existing methods for penicillin susceptibility testing. The aims of the present study were to determine the frequency of penicillin-susceptible SA isolates from blood and wound cultures in Lund, Sweden, and to evaluate methods for penicillin testing in SA. We also wanted to investigate if penicillin-susceptible isolates are associated with higher mortality. Methods: Hundred blood culture isolates collected 2008/2009, 140 blood culture isolates from 2014/2015, and 141 superficial wound culture strains from 2015 were examined. Penicillin susceptibility was tested with disk diffusion according to EUCAST guidelines, and results were confirmed with a cloverleaf assay and PCR amplification of the BlaZ gene. Patient data for all bacteraemia cases were extracted from medical records. Results: The disk diffusion method with assessment of both zone size and zone edge appearance had high accuracy in our study. About 57% of bacteraemia isolates from 2008/2009 were sensitive to penicillin compared to 29% in 2014/2015 (p &lt; .0001). In superficial wound cultures, 21% were penicillin susceptible. There was no difference in co-morbidity or mortality rates between patients with penicillin resistant and penicillin sensitive SA bacteraemia. Conclusion: Disk-diffusion is a simple and reliable method to detect penicillin resistance in SA, and susceptibility rates are significant. Penicillin has many theoretical advantages and should be considered in the treatment of SA bacteraemia when susceptible.</p>},
  author       = {Hagstrand Aldman, Malin and Skovby, Annette and I. Påhlman, Lisa},
  issn         = {2374-4235},
  keyword      = {disk diffusion,mortality,penicillin susceptibility,Staphylococcus aureus},
  language     = {eng},
  month        = {01},
  number       = {6},
  pages        = {454--460},
  publisher    = {Informa Healthcare},
  series       = {Infectious Diseases},
  title        = {Penicillin-susceptible Staphylococcus aureus : susceptibility testing, resistance rates and outcome of infection},
  url          = {http://dx.doi.org/10.1080/23744235.2017.1280617},
  volume       = {49},
  year         = {2017},
}