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Increase of beta-Lactam-Resistant Invasive Haemophilus influenzae in Sweden, 1997 to 2010

Resman, Fredrik LU ; Ristovski, Mikael LU ; Forsgren, Arne LU ; Kaijser, Bertil; Kronvall, Goran; Medstrand, Patrik LU ; Melander, Eva LU ; Odenholt, Inga LU and Riesbeck, Kristian LU (2012) In Antimicrobial Agents and Chemotherapy 56(8). p.4408-4415
Abstract
The proportions of Haemophilus influenzae resistant to ampicillin and other beta-lactam antibiotics have been low in Sweden compared to other countries in the Western world. However, a near-doubled proportion of nasopharyngeal Swedish H. influenzae isolates with resistance to beta-lactams has been observed in the last decade. In the present study, the epidemiology and mechanisms of antimicrobial resistance of H. influenzae isolates from blood and cerebrospinal fluid in southern Sweden from 1997 to 2010 (n = 465) were studied. Antimicrobial susceptibility testing was performed using disk diffusion, and isolates with resistance to any tested beta-lactam were further analyzed in detail. We identified a significantly increased (P = 0.03)... (More)
The proportions of Haemophilus influenzae resistant to ampicillin and other beta-lactam antibiotics have been low in Sweden compared to other countries in the Western world. However, a near-doubled proportion of nasopharyngeal Swedish H. influenzae isolates with resistance to beta-lactams has been observed in the last decade. In the present study, the epidemiology and mechanisms of antimicrobial resistance of H. influenzae isolates from blood and cerebrospinal fluid in southern Sweden from 1997 to 2010 (n = 465) were studied. Antimicrobial susceptibility testing was performed using disk diffusion, and isolates with resistance to any tested beta-lactam were further analyzed in detail. We identified a significantly increased (P = 0.03) proportion of beta-lactam-resistant invasive H. influenzae during the study period, which was mainly attributed to a significant recent increase of beta-lactamase-negative beta-lactam-resistant isolates (P = 0.04). Furthermore, invasive beta-lactamase-negative beta-lactam-resistant H. influenzae isolates from 2007 and onwards were found in higher proportions than the corresponding proportions of nasopharyngeal isolates in a national survey. Multiple-locus sequence typing (MIST) of this group of isolates did not completely separate isolates with different resistance phenotypes. However, one cluster of beta-lactamase-negative ampicillin-resistant (BLNAR) isolates was identified, and it included isolates from all geographical areas. A truncated variant of a beta-lactamase gene with a promoter deletion, bla(TEM-1)-P Delta dominated among the beta-lactamase-positive H. influenzae isolates. Our results show that the proportions of beta-lactam-resistant invasive H. influenzae have increased in Sweden in the last decade. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Antimicrobial Agents and Chemotherapy
volume
56
issue
8
pages
4408 - 4415
publisher
American Society for Microbiology
external identifiers
  • wos:000306826300046
  • scopus:84864387279
ISSN
1098-6596
DOI
10.1128/AAC.00415-12
language
English
LU publication?
yes
id
5915177c-cdb8-490c-823f-93ec4645ee91 (old id 3188087)
date added to LUP
2012-12-03 07:08:47
date last changed
2017-11-19 03:57:22
@article{5915177c-cdb8-490c-823f-93ec4645ee91,
  abstract     = {The proportions of Haemophilus influenzae resistant to ampicillin and other beta-lactam antibiotics have been low in Sweden compared to other countries in the Western world. However, a near-doubled proportion of nasopharyngeal Swedish H. influenzae isolates with resistance to beta-lactams has been observed in the last decade. In the present study, the epidemiology and mechanisms of antimicrobial resistance of H. influenzae isolates from blood and cerebrospinal fluid in southern Sweden from 1997 to 2010 (n = 465) were studied. Antimicrobial susceptibility testing was performed using disk diffusion, and isolates with resistance to any tested beta-lactam were further analyzed in detail. We identified a significantly increased (P = 0.03) proportion of beta-lactam-resistant invasive H. influenzae during the study period, which was mainly attributed to a significant recent increase of beta-lactamase-negative beta-lactam-resistant isolates (P = 0.04). Furthermore, invasive beta-lactamase-negative beta-lactam-resistant H. influenzae isolates from 2007 and onwards were found in higher proportions than the corresponding proportions of nasopharyngeal isolates in a national survey. Multiple-locus sequence typing (MIST) of this group of isolates did not completely separate isolates with different resistance phenotypes. However, one cluster of beta-lactamase-negative ampicillin-resistant (BLNAR) isolates was identified, and it included isolates from all geographical areas. A truncated variant of a beta-lactamase gene with a promoter deletion, bla(TEM-1)-P Delta dominated among the beta-lactamase-positive H. influenzae isolates. Our results show that the proportions of beta-lactam-resistant invasive H. influenzae have increased in Sweden in the last decade.},
  author       = {Resman, Fredrik and Ristovski, Mikael and Forsgren, Arne and Kaijser, Bertil and Kronvall, Goran and Medstrand, Patrik and Melander, Eva and Odenholt, Inga and Riesbeck, Kristian},
  issn         = {1098-6596},
  language     = {eng},
  number       = {8},
  pages        = {4408--4415},
  publisher    = {American Society for Microbiology},
  series       = {Antimicrobial Agents and Chemotherapy},
  title        = {Increase of beta-Lactam-Resistant Invasive Haemophilus influenzae in Sweden, 1997 to 2010},
  url          = {http://dx.doi.org/10.1128/AAC.00415-12},
  volume       = {56},
  year         = {2012},
}