TY - JOUR
T1 - Increase of beta-Lactam-Resistant Invasive Haemophilus influenzae in Sweden, 1997 to 2010
AU - Resman, Fredrik
AU - Ristovski, Mikael
AU - Forsgren, Arne
AU - Kaijser, Bertil
AU - Kronvall, Goran
AU - Medstrand, Patrik
AU - Melander, Eva
AU - Odenholt, Inga
AU - Riesbeck, Kristian
N1 - The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Clinical Microbiology, Malmö (013011000), Infectious Diseases Research Unit (013242010), Molecular Virology (013212007)
PY - 2012
Y1 - 2012
N2 - 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.
AB - 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.
U2 - 10.1128/AAC.00415-12
DO - 10.1128/AAC.00415-12
M3 - Article
C2 - 22687505
SN - 1098-6596
VL - 56
SP - 4408
EP - 4415
JO - Antimicrobial Agents and Chemotherapy
JF - Antimicrobial Agents and Chemotherapy
IS - 8
ER -