Community spread and late season increased incidence of oseltamivir-resistant influenza A(H1N1) viruses in Norway 2016.

BACKGROUND: Antiviral resistance in Norwegian influenza viruses is rare. Only one A(H1N1)pdm09 virus from May 2015 had been found resistant to oseltamivir since the introduction of these viruses in 2009. OBJECTIVES: Surveillance of antiviral resistance is part of the Norwegian surveillance system, to rapidly detect the development of antiviral-resistant viruses and spread in the community. We describe the spread of oseltamivir-resistant A(H1N1)pdm09 viruses in Norway in the 2016-17 season, found as part of the routine surveillance. METHODS: Influenza H1N1 viruses were analysed for antiviral resistance by pyrosequencing, neuraminidase susceptibility assay and by Sanger sequencing of the HA and NA genes. RESULTS: During the 2015-16 influenza season, 3% of all A(H1N1)pdm09 viruses screened for resistance in Norway were resistant to oseltamivir, possessing the H275Y substitution in the neuraminidase protein. In comparison, the overall frequency in Europe was 0.87%. Out of these, 37% (n = 10) were reported from Norway. Most cases in Norway were not related to antiviral treatment, and the cases were from several different locations of southern Norway. Genetic analysis revealed that resistant virus emerged independently on several occasions and that there was some spread of oseltamivir-resistant influenza A(H1N1)6B.1 viruses in the community, characterised by a N370S substitution in the haemagglutinin and T48I in the neuraminidase. CONCLUSIONS: Our findings emphasise the importance of antiviral resistance surveillance in the community, not only in immunocompromised patients or other patients undergoing antiviral treatment.

Cigarette smoking and risk of subsequent use of antibacterials: a follow-up of 365,117 men and women.

OBJECTIVES: Antibacterial prescribing is driving antibiotic resistance. We aimed to analyse whether smoking habits are associated with susceptibility to be prescribed antibacterials in primary care and to examine whether patients' smoking habits influence physicians' choice of therapy. METHODS: Information on smoking habits from health surveys in 1985-99 was related to use of antibacterials 5-25 years later by linkage to the Norwegian Prescription Database. The study population included 365 117 men and women, 40-45 years old. Individuals likely to have chronic obstructive airway disease were excluded. Relative risk (RR) of being dispensed antibacterials for systemic use was calculated for five levels of smoking intensity with never smokers as reference. Adjustments were made for age, education, marital status, household size, body mass index and residence (rural/urban). RESULTS: Fifty-six percent of the male and 69% of the female never smokers received at least one antibacterial prescription in the whole period, increasing to 68% and 82%, respectively, in heavy smokers (>19 cigarettes/day) (adjusted RR 1.17 and 1.16). The percentage receiving at least one antibacterial prescription every year was 0.5% in male and 1.9% in female never smokers, increasing to 1.1% and 4.0%, respectively, in heavy smokers (adjusted RR 2.07 and 1.89). The proportion of antibacterial users who were prescribed broad-spectrum antibacterials increased with increasing cigarette consumption. CONCLUSIONS: Smoking habits influenced the usage of antibacterials years later with a dose-response relationship. Prescribers seem to acknowledge smoking as a risk factor for resistant bacteria since broad-spectrum antibacterials are more frequently prescribed to smokers than never smokers.

[Antibiotic use in Norway]. / Antibiotikaforbruk i Norge.

BACKGROUND: Antibiotic use is a major cause of development and spread of resistant bacteria. Sensible antibiotic use should aim at decreasing total antibiotic use and replace broad-spectrum antibiotics with narrow-spectrum ones; pharmaceutical drug statistics are vital in this context. MATERIAL AND METHODS: Data were collected from the wholesaler-based drug statistics (for the period 1974 - 2007) and from the Norwegian Prescription Database (2006). The ATC/DDD methodology is used in the drug statistics. Data are presented as number of users (prevalence), number of dispensed prescriptions, defined daily doses (DDD per 1 000 inhabitants per day) and in Norwegian kroner. RESULTS AND INTERPRETATIONS: Longitudinal trends show a relatively stable and high use of narrow-spectrum antibiotics, even though broad-spectrum antibiotic use is slightly increasing. Antibiotic use varies largely by age and sex. The highest prevalences are seen among small children (0 - 5 years), women in their twenties and in people over 70 years. Over 30 % of people in these groups receive at least one antibiotic per year. The therapy profile differs between the types of prescription issued. Neither the wholesaler statistics nor the Prescription Database contains information on diagnosis, making it difficult to monitor whether the Norwegian primary health service has a rational antibiotic therapy.

Age- and gender-specific antibacterial prescribing in Norway.

OBJECTIVES: To describe the use of antibacterials among outpatients in Norway and to explore patterns of age- and gender-specific use. METHODS: Data were extracted from the Norwegian Prescription Database (NorPD), a complete register of all dispensed prescriptions in Norway, in the period 1 July 2005-30 June 2006. NorPD contains data at an individual level. We extracted patients who had received an antibacterial for systemic use. Results were shown as population prevalences for the total population. RESULTS: A total of 1.1 million persons had at least one prescription for an antibacterial dispensed. The mean population prevalence of antibacterial use was 24% in total (28% and 19% for women and men, respectively). Population prevalence changed markedly between different age groups and between genders. Children (<5 years) and older elderly people (>or=75 years) were high consumers. Females, in general, used more than males. Use by the different subgroups of antibacterials differed between gender and between different age groups. beta-Lactamase-sensitive penicillins was the most prevalent antibacterial group in all age groups except for women >or=75 years, for whom penicillins with extended spectrum were the most frequently used. Individuals defined as high users (using more than 60 DDDs/year) represented 3% of the population who were using antibacterials. These patients were older and used co-medication more often than other users of antibacterials. CONCLUSIONS: Over 1 year, a quarter of the total population used antibacterials. Patterns of use and types of drugs used differed markedly between genders and between different age groups.