Previous Article | Next Article 
Antimicrobial Agents and Chemotherapy, May 2009, p. 2066-2073, Vol. 53, No. 5
0066-4804/09/$08.00+0 doi:10.1128/AAC.01464-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Temporal Trends of Antimicrobial Resistance and Clonality of Invasive Streptococcus pneumoniae Isolates in Finland, 2002 to 2006
Lotta Siira,1,
*
Merja Rantala,1,
Jari Jalava,1
Antti J. Hakanen,1
Pentti Huovinen,1
Tarja Kaijalainen,2
Outi Lyytikäinen,1 and
Anni Virolainen1
Department of Infectious Disease Surveillance and Control, National Institute for Health and Welfare, Helsinki, Finland,1 Department of Lifecourse and Services, National Institute for Health and Welfare, Oulu, Finland2
Received 3 November 2008/ Returned for modification 29 December 2008/ Accepted 1 March 2009
The antimicrobial resistance of Streptococcus pneumoniae, or pneumococcus, is a growing global problem. In our study, 3,571 invasive pneumococcal isolates, recovered from blood and cerebrospinal fluid samples from patients in Finland between the years 2002 and 2006, showed an increase in erythromycin nonsusceptibility from 16% to 28% (P < 0.0001) over the 5-year study period, as well as a doubling of penicillin nonsusceptibility from 8% to 16% (P < 0.0001). Erythromycin nonsusceptibility increased especially in isolates derived from 0- to 2-year-old children and was 46% for this age group in 2006. Although multiresistance, defined as nonsusceptibility to penicillin, erythromycin, and tetracycline, was fairly rare (5.1% in 2006), 38% of the erythromycin-nonsusceptible isolates were also penicillin nonsusceptible, while 74% of the penicillin-nonsusceptible isolates were nonsusceptible to erythromycin. In contrast to the situation in continental Europe, but mirroring that in North America, the most frequent macrolide resistance determinant carried by 56% of the tested macrolide-resistant pneumococci was the mef gene. Serotypes 14, 9V, 19A, 6B, and 19F were most frequently nonsusceptible to erythromycin or penicillin. The penicillin-resistant invasive isolates (n = 88) were genotyped by multilocus sequence typing, which revealed the presence of 25 sequence types, 9 of which were novel. The majority of the isolates were related to one of several globally disseminated penicillin- or multiresistant clones, most importantly the rlrA adhesion pilus carrying clones Spain9V ST156 and Taiwan19F ST236. The penicillin-resistant pneumococcal population in Finland is therefore a combination of internationally recognized genotypes as well as novel ones.
* Corresponding author. Mailing address: National Institute for Health and Welfare (THL), Department of Infectious Disease Surveillance and Control, PL 30, FI-00271 Helsinki, Finland. Phone: 358 20 610 8755. Fax: 358 20 610 8238. E-mail: lotta.siira{at}thl.fi
Published ahead of print on 9 March 2009.
Both authors contributed equally to this publication.
Antimicrobial Agents and Chemotherapy, May 2009, p. 2066-2073, Vol. 53, No. 5
0066-4804/09/$08.00+0 doi:10.1128/AAC.01464-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»