The situation in Sweden regarding antibiotic resistance in bacteria in humans and animals is still favourable from an international perspective. This confirms that our strategies to promote the rational use of antibiotics and to limit the spread of antibiotic resistance are effective. Despite our comparatively good situation, there are problems with cross infection and increasing antibiotic resistance, which motivates continued efforts in preventive work. An important example is the recurrent outbreaks of vancomycin-resistant enterococci (VRE) in hospitals. This is described in more detail in an In Focus section of this Swedres-Swarm report. Over the last decades the consumption of antibiotics in Sweden has decreased in both humans and in animals. In addition, the sales of broad-spectrum antibiotics have decreased while the use of narrow-spectrum antibiotics has increased. Despite this, many of the monitored types of antibiotic resistance have continued to increase over the years, even if exceptions to these negative trends occur.
Key findings 2018
- Two regions, Jämtland and Västerbotten, reached the national target for antibiotic prescriptions to humans of 250 prescriptions per 1 000 inhabitants per year. This longterm goal is intended to reduce unnecessary antibiotic use.
- The national average for antibiotic prescription to humans is now below 300 prescriptions per 1 000 inhabitants per years, which is a historically low level.
- One large and several small VRE outbreaks occurred in hospitals. VRE usually affects sensitive patient groups where the use of antibiotics is high. During the year, an outbreak strain of VRE caused septicaemia in five patients.
- High resistance to ciprofloxacin was seen in Escherichia coli and Klebsiella pneumoniae, both from urine and blood from humans. Ciprofloxacin is used in the treatment of febrile urinary tract infection, and when used for empirical treatment it is important to consider this high level of resistance.
- Resistance in E. coli to mecillinam and nitrofurantoin, used for first-line treatment of uncomplicated urinary tract infection, is still low, four and one percent respectively.
- High levels of resistance to erythromycin and clindamycin were observed in Streptococcus agalactiae (GBS). These antibiotics are alternatives to penicillin in cases of allergy. S. agalactiae can cause severe infections in children in the neonatal period.
- Increasing numbers of Enterobacteriaceae with ESBLCARBA were observed. These are extremely resistant, and there are few treatment options in case of infection. Early detection and prevention of spread within human health care is therefore important.
- Consumption of antibiotics for animals is stable at a low level and is dominated by narrow-spectrum penicillin.
- MRSA is unusual among both farm and companion animals.
- The occurrence of ESBL-producing E. coli in caecal and meat samples from broilers has decreased significantly compared to previous years.
- ESBLCARBA-producing bacteria have not been detected in animals in Sweden.
Consumption of antibiotics
Antibiotic consumption in humans
The total sales of antibiotics to humans in Sweden was 4.4% lower in 2018 than in 2017 and the national average is now 11.7 DDD per 1 000 inhabitants per day. This figure encompasses all antibiotics sold on prescription to individuals, as well as antibiotics sold to hospitals and other health care facilities for dispensing to patients and clients. For the Region Dalarna, only prescription data are included because the region failed to supply data on hospital sales during 2018. The sales of antibiotics have decreased by approximately 19% since the year 2000.
The decrease in sales in outpatient care during 2018 encompasses the majority of all antibiotic groups, except betalactamase resistant penicillins (J01CF), trimethoprim with sulphonamides (J01EE), and nitrofurantoin (J01XE). Persistent availability problems affecting oral suspensions of amoxicillin with clavulanic acid and cefadroxil, as well as the withdrawal of ceftibuten in 2017, might partly explain the lower sales of combinations of penicillins (J01CR) and cephalosporins (J01DB-DE).
Hospitals and other health and social care facilities
In 2018, sales were slightly lower than in 2017 and the overall figure is now 1.52 DDD per 1 000 inhabitants per day. This reflects all antibiotics sold for dispensing in hospitals, nursing homes and other healthcare facilities.
Data from acute care hospitals show that the consumption of antibiotics was slightly higher in 2018 compared with 2017, both when measured as DDD per 100 patient-days and as DDD per 100 admissions. Beta-lactamase-resistant penicillins (J01CF) still represent the greatest number of DDDs. There are large differences in consumption of antibiotics between Swedish acute care hospitals, for example, in the relative use of narrow-spectrum penicillins, which make up between 6.1% and 18.6% of the total acute care hospital consumption measured in DDDs. The use of broad-spectrum antibiotics – cephalosporins, carbapenems, fluoroquinolones, and piperacillin with tazobactam – also shows regional variation in terms of which substances are used, although the overall level is similar within the country.
Sales of antibiotics for animals
In 2018, reported sales of antibiotics for animals were 10 042 kg, of which 58% were narrow-spectrum penicillins. The corresponding figures for 2009 were 15 368 kg and 50%, respectively.
Since the withdrawal of growth-promoting antibiotics from the market in 1986, the total sales of antibiotics have decreased by around two thirds when corrected for population sizes over time. During the 1990s, sales of veterinary products for medication of groups of animals decreased, and in the past decade there has also been a decrease in sales of products for use in individual animals.
Comparing consumption of antibiotics in human and veterinary medicine
In 2018, a total of 59.5 tonnes of antibiotics were sold for human use and 10.0 tonnes were sold for animal use.
Measured as milligrams of active substance per kilogram biomass, the consumption was 88.6 and 12.7 milligrams per kilogram, respectively. Consumption by humans still dominates for all included classes of antibiotics except for trimethoprim-sulphonamides.
ESBL-producing Enterobacteriaceae in humans have been subject to mandatory notification since 2007. This is the most common of the antibiotic resistance types where notification is required.
Results 2018, Enterobacteriaceae with ESBL
- The number of reported cases: 10 341 (previous year 10 084), relative change +2.5%.
- The number of cases of septicaemia: 703 (previous year 594), relative change +18%.
- As in previous years, E. coli was the most common species, 87%, followed by K. pneumoniae, 9%.
Results 2018, Enterobacteriaceae with ESBLCARBA
- The number of reported cases: 144 (previous year 116), relative change +24%.
- The number of cases with septicaemia: 7 (previous year 2).
- Among Enterobacteriaceae with ESBLCARBA, E. coli was the most common species, 60%, followed by K. pneumoniae, 33%.
ESBL-producing Enterobacteriaceae are, with the exception of broilers, rare among animals in Sweden. In 2018, the occurrence of ESBL-producing E. coli in caecal and meat samples from broilers, caecal samples from turkeys, and intestinal samples from cattle under one year of age were investigated with screening methods. Such bacteria were isolated from 13% of the intestinal samples and 12% of the meat samples from broilers of Swedish origin. This is a significant decrease from previous years and is most likely explained by decreased occurrence of ESBL-producing E. coli in the breeding pyramid. Bacteria that form ESBLCARBA have not been detected in animals in Sweden.
Community-acquired infection has long been the most common type in humans, with more than two-thirds of the cases. In 2015, it was divided into family-/household-related infection and community-acquired infection. Family/household-related infections accounted for 39% of the cases in 2018.
- The number of reported human cases: 3 864 (previous year 3 735), relative change + 3.5%.
- The number of cases with septicaemia: 64 (previous year 55), relative change + 16%.
- About 30 smaller outbreaks in health- and elderly care were reported.
The occurrence of MRSA in animals in Sweden is still low, which limits the spread from animals to humans. MRSA was found sporadically in cats, dogs and horses in 2018, and MRSA with mecC was detected in samples from hedgehogs in a research project. In companion animals, the same types of MRSA as in humans dominate, indicating a human source of MRSA in these animals. In horses, livestock-associated MRSA clonal complex 398 is the most common.
In 2018, there were 57 cases of methicillin-resistant Staphylococcus pseudintermedius (MRSP) notified to the Swedish Board of Agriculture. All cases except one were related to dogs. This number is about the same level as in recent years. The epidemiology of MRSP is becoming more diverse compared to earlier years with several sequence types occurring.
MRSP in humans is not notifiable.
- The number of reported cases: 91 (previous year 61), relative change + 50%.
- The number of cases with septicaemia: 3 (previous year 5).
- An outbreak in preschools in Örebro county that included 18 cases.
- The number of reported cases: 444 (previous year 244), relative change + 82%.
- The number of reported cases of E. faecium with vancomycin resistance: 438 (previous year 236), relative change +54%.
- The number of reported cases: of E. faecalis with vancomycin resistance: 6 (previous year 8).
- The number of cases with septicaemia: 9 (previous year 2).
- Nineteen hospital-related outbreaks were reported during the year, including one larger (261 cases), three smaller with 5-15 cases each, and the rest with only 2-4 cases each.
Salmonella is rare in animals in Sweden, and few incidents involve antibiotic-resistant strains. Strains with ESBL resistance have never been found in isolates from animals in Sweden, and resistance to fluoroquinolones is rare. Isolates from human invasive infections are markedly more resistant, which makes animals in Sweden an unlikely source for these infections.
Campylobacter from animals in Sweden are generally susceptible to relevant antibiotics, and resistance to erythromycin, for example, is most uncommon.
Infections, either in humans or in animals, caused by Salmonella and Campylobacter are usually not treated with antibiotics. In humans, only a small proportion are tested for susceptibility, and most of these isolates are related to serious infections. See the “Comparative analysis” section of each bacterium.
Human clinical isolates
All data for these compilations are collected automatically via Svebar, a collaboration between the clinical laboratories and
the Public Health Agency.
- E. coli: Resistance in blood isolates to cefotaxime and ceftazidime was 7-8%, to compare with the 470 reported cases of E. coli ESBL from blood in 2018. Resistance to ciprofloxacin is now 18 and 12%, in isolates from blood and urine, respectively and this needs to be noted when choosing empirical treatment for febrile urinary tract infection. Resistance in E. coli to mecillinam and nitrofurantoin, used for first-line treatment of uncomplicated urinary tract infection, is still low, four and one percent respectively.
- K. pneumoniae: Resistance of blood isolates to cefotaxime and ceftazidime was 5%, to compare with the 66 reported cases of K. pneumoniae ESBL from blood 2018: 66. As for E. coli, resistance to ciprofloxacin is now relatively high, 10-11% in isolates from blood and urine. • S. aureus: Resistance to cefoxitin (which is indicative of MRSA) in isolates from blood and samples from skin and soft tissue was 1.9%, to compare with the 64 of reported cases of MRSA from blood 2018.
- S. agalactiae (GBS): Resistance to erythromycin and clindamycin has gradually increased and is now about 20% for both of these antibiotics in blood isolates.
- Clostridioides difficile: The incidence has decreased by 25% from 2009 to 2016 and subsequently remained unchanged. Like previous years, all isolates tested were susceptible to metronidazole and vancomycin.
Animal clinical isolates
Bacteria causing clinical disease in animals are mostly susceptible to antibiotics relevant for treatment. Respiratory pathogens from farm animals and horses are generally susceptible to bensylpenicillin, but penicillin resistance is common in Staphylococcus pseudintermedius from dogs and occurs in S. aureus from horses and S. felis from cats. Resistance in E. coli occurs in all animals but is most prominent in enteric isolates from young calves. Susceptibility testing for guidance in antibiotic therapy is warranted, especially for staphylococci, E. coli and, Brachyspira spp.
Indicator bacteria from healthy animals
Antibiotic resistance in E. coli from the intestinal flora of healthy animals serves as an indicator for the presence of resistance in an animal population. The prevalence of acquired resistance in such commensal bacteria also indirectly indicates the magnitude of the selective pressure from the use of antibiotics in an animal population. The prevalence of resistance in indicator bacteria from animals in Sweden is generally low, and the situation is favourable in an international perspective.