Epidemiology of invasive group A streptococcal infections in Norway 2010-2014: A retrospective cohort study.
Streptococcus pyogenes or group A streptococcus (GAS) causes mild to severe infections in humans. GAS genotype emm1 is the leading cause of invasive disease worldwide. In the Nordic countries emm28 has been the dominant type since the 1980s. Recently, a resurgence of genotype emm1 was reported from Sweden. Here we present the epidemiology of invasive GAS (iGAS) infections and their association with emm-types in Norway from 2010-2014. We retrospectively collected surveillance data on antimicrobial susceptibility, multilocus sequence type and emm-type, and linked them with demographic and clinical manifestation data to calculate age and sex distributions, major emm- and sequence types and prevalence ratios (PR) on associations between emm-types and clinical manifestations. We analysed 756 iGAS cases and corresponding isolates, with overall incidence of 3.0 per 100000, median age of 59 years (range, 0-102), and male 56 %. Most frequent clinical manifestation was sepsis (49 %) followed by necrotizing fasciitis (9 %). Fifty-two different emm-types and 67 sequence types were identified, distributed into five evolutionary clusters. The most prevalent genotype was emm1 (ST28) in all years (range, 20-33 %) followed by 15 % emm28 in 2014. All isolates were susceptible to penicillin, 15 % resistant to tetracycline and <4 % resistant to erythromycin. A PR of 4.5 (95 % CI, 2.3-8.9) was calculated for emm2 and necrotizing fasciitis. All emm22 isolates were resistant to tetracycline PR 7.5 (95 % CI, 5.8-9.9). This study documented the dominance of emm1, emergence of emm89 and probable import of tetracycline resistant emm112.2 into Norway (2010-2014). Genotype fluctuations between years suggested a mutual exclusive dominance of evolutionary clades.
Domain for Environmental Health and Infectious Disease Control, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway. mohammed.umaer.naseer@fhi.no.|European Programme for Public Health Microbiology Training (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden. mohammed.umaer.naseer@fhi.no.
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Naseer
Domain for Environmental Health and Infectious Disease Control, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway.
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Steinbakk
Domain for Environmental Health and Infectious Disease Control, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway.
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Blystad
Domain for Environmental Health and Infectious Disease Control, Norwegian Institute of Public Health, P. O. Box 4404, Nydalen, 0403, Oslo, Norway.|Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Caugant
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D024881:Drug Resistance, Bacterial; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D009664:Norway / Q000453:epidemiology; D012189:Retrospective Studies; D013290:Streptococcal Infections / Q000453:epidemiology*; D013297:Streptococcus pyogenes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein