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Swedres-Svarm reports

Reports from Svarm, Swedish Veterinary Antimicrobial Resistance Monitoring.

Summary

The situation in Sweden regarding antibiotic resistance in bacteria from 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 in hospitals. In the last decades the sales of antibiotics in Sweden have decreased for both humans and for animals. In addition, the sales of broad-spectrum antibiotics have decreased while the use of narrow-spectrum antibiotics have 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 2019

  • The national average for antibiotic prescriptions to humans continued to decrease in 2019.
  • The sales of antibiotics in dentistry show a trend downwards, which has continued to decrease.
  • Increasing numbers of Enterobacteriaceae with ESBLCARBA in humans. These are extremely resistant and there are few treatment options in case of infection. Early detection and prevention of the spread within human health care is therefore important.
  • Several small VRE outbreaks in hospitals. VRE usually affects sensitive patient groups where the use of antibiotics is high. During the year, VRE caused septicemia in ten patients, seven of which were caused by outbreak strains.
  • Increasing mecillinam resistance in Escherichia coli and Klebsiella pneumoniae from urine from humans. The levels are still quite low but it is of importance to continue to follow this trend as pivmecillinam is one of the recommended first-line treatments for urinary tract infections.
  • Sales of antibiotics for animals are stable at a low level and dominated by narrow-spectrum penicillin.
  • MRSA is unusual among both farm and companion animals.
  • The decreased occurrence of ESBL-producing E. coli in samples from broilers that has been seen in the latest years continued in 2019.
  • ESBLCARBA-producing bacteria have not been detected in animals in Sweden.

Sales of antibiotics

Sales of antibiotics for humans

The total sales of antibiotics for humans in Sweden were 2.3% lower in 2019 and are now 11.1 DDD per 1 000 inhabitants per day. This figure encompasses all antibiotics sold on prescriptions to individuals, as well as antibiotics sold to hospitals and other health care facilities for dispensing to patients and clients. After a shortage of combinations of penicillins (J01CR), the sales of this antibiotic subclass has now increased.

Outpatient care

A decrease was seen among the sales of antibiotics in outpatient care in 2019. The distribution of use of the different antibiotic classes shows a trend towards an increased use of first-line antibiotics. Compared to 2018, the biggest decrease of sales in the different age groups is found among children. The national average sales in prescriptions per 1 000 inhabitants per year were 285 in 2019 and continue to decrease. One region was below the long-term target of 250 prescriptions per 1000 inhabitants per year. The sales of antibiotics in dentistry have decreased for several years and continued to do so in 2019 by an additional 4.4%, compared with 2018. Since 2007 the sales in dentistry have been reduced by half. Around 3% of prescriptions in outpatient care were issued in telemedicine in 2019.

Hospitals and other health and social care facilities

In 2019, the sales of antibiotics on requisition decreased to 1.42 DDD per 1 000 inhabitants per day, a decrease of 0.8% compared with 2018. This reflects all antibiotics sold for dispensing in hospitals, nursing homes and other healthcare facilities. The sales of antibiotics to acute care hospitals show an even level, expressed both as DDD per 100 patient-days and as DDD per 100 admissions. An increase is seen among combinations of penicillins and trimethoprim with sulphonamides. Beta-lactamase resistant penicillins (J01CF) still represent the highest number of DDDs. There are large differences in sales of antibiotics between Swedish acute care hospitals, for example in the relative use of narrow-spectrum penicillins. The use of broad-spectrum antibiotics – cephalosporins, carbapenems, fluoroquinolones and piperacillin-tazobactam – also shows regional variation in terms of which substances are used.

Sales of antibiotics for animals

In 2019, reported sales of antibiotics for animals were 9 601 kg, of which 58% were penicillins with narrow-spectrum. The corresponding figures for 2010 were 14 117 kg and 53%, respectively. Since the withdrawal of growth-promoting antibiotics from the Swedish 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 sales of antibiotics in human and veterinary medicine

In 2019, a total of 61.0 tonnes of antibiotics were sold for human use and 9.5 tonnes were sold for animal use (excluding products for intramammary or intrauterine use). Measured as milligrams of active substance per kilogram biomass, the sales were 90.8 and 12.0 milligrams per kilogram, respectively. Antibiotic sales for humans still dominate for all included classes of antibiotics except for aminoglycosides.

Notifiable resistance

ESBL-producing Enterobacteriaceae

ESBL-producing Enterobacteriaceae in humans has been subject to mandatory notification since 2007. It is the most common one of the antibiotic resistance types where notification is required.

Results 2019, Enterobacteriaceae with ESBL

  • Number of reported cases: 10 717 (previous year 10 341), relative change +3.6%.
  • Number of bloodstream infections: 835 (previous year 703), relative change +19%.
  • As in previous years, Escherichia coli was the most common species, 86%, followed by Klebsiella pneumoniae, 10%.

Results 2019, Enterobacteriaceae with ESBLCARBA

  • Number of reported cases: 201 (previous year 144), relative change +40%.
  • Number of bloodstream infections: 6 (previous year 7).
  • Among Enterobacteriaceae with ESBLCARBA, E. coli was the most common species, 64%, followed by K. pneumoniae, 28%.

ESBL-producing Enterobacteriaceae are rare among animals in Sweden. Previously, the occurrence in intestinal samples from broilers was high but it has decreased in recent years. In 2019, the occurrence of ESBL-producing E. coli in intestinal samples from pigs and broilers, as well as samples of pork and beef was investigated with screening methods. Such bacteria were isolated from 3% of the intestinal samples from pigs and broilers respectively, and <1% and 0 % of the pork and beef samples of Swedish origin.

MRSA

Community-acquired infection has long been the most common type in humans, with two-thirds of the cases. In 2015, community-acquired infection was divided into family-/household-related infection and community-acquired infection. Family-/household-related infections accounted for 33% of the cases.

Results 2019

  • Number of reported cases: 3 858 (previous year 3 864), relative change -0.2%.
  • Number of bloodstream infections: 72 (previous year 64), relative change +13%.

The occurrence of MRSA in animals in Sweden is still low, which limits the spread from animals to humans. MRSA was found sporadically in dog, cat, horse, rabbit and goat in 2019, 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.

MRSP

In 2019, the number of reported cases of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in animals was around the same level as in previous years. In total 48 cases of MRSP were notified to the Swedish Board of Agriculture, and isolates from 42 cases (38 dogs, 3 cats and 1 horse) were available for further investigations. The epidemiology of MRSP is becoming more diverse compared to earlier years with several sequence types occurring. MRSP in humans is not notifiable.

PNSP

Results 2019

  • Number of reported cases: 118 (previous year 91), relative change +30%.
  • Number of bloodstream infections: 9 (previous year 3).
  • Changes in the methodology for detection of PNSP resulted in more cases reported.
  • One small outbreak in a preschool was reported.

VRE

Results 2019

  • Total number of reported cases: 232 (previous year 444), relative change -48%.
  • Number of reported cases of E. faecium with vancomycin resistance: 221 (previous year 438), relative change -50 %.
  • Number of reported cases of E. faecalis with vancomycin resistance: 11 (previous year 6).
  • Number of bloodstream infections: 10 (previous year 9).
  • Twenty-two hospital-related outbreaks were reported during the year. Five outbreaks with 5-15 cases each and the remaining were small clusters with 2-4 cases each.

Zoonotic pathogens

Salmonella is rare in animals in Sweden, and only a few of the incidents involve antibiotic-resistant strains. Resistance
to fluoroquinolones is rare and in 2019 a strain with ESBL resistance was for the first time detected, this in an environmental sample from a farm. For Salmonella species isolated from human faeces the highest occurrence of resistance was against quinolones, 20%. No resistance to meropenem was reported. 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. In Campylobacter jejuni from humans, resistance to ciprofloxacin was 61% and to tetracycline 33% in 2019. One percent was resistant to erythromycin.

Infections, either in humans or in animals, caused by Salmonella and Campylobacter are usually not treated with antibiotics. In humans, only a small proportion of the isolates are tested for antibiotic susceptibility, most of which are related to serious infections. See the “Comparative analysis” section of each bacterium.

Human clinical isolates

All data for these compilations is collected automatically via Svebar, a collaboration between the clinical microbiological laboratories and the Public Health Agency.

  • Escherichia coli: resistance in blood isolates to cefotaxime and ceftazidime was 7-8 percent, to compare with the number of reported E. coli ESBL from blood 2019: 700. Resistance to ciprofloxacin is now 14% and 11%, respectively, in isolates from blood and urine. This needs to be noted when choosing empirical treatment for febrile urinary tract infection.
  • When E. coli from urine are age and gender distributed, some differences in resistance are seen. Most prominent is the high ciprofloxacin resistance seen among men, 20 years and older.
  • Klebsiella pneumoniae: resistance in blood isolates to cefotaxime and ceftazidime was 7%, to compare with the number of reported K. pneumoniae ESBL from blood 2019: 125. As for E. coli, resistance to ciprofloxacin is now relatively high, 8-10% in isolates from blood and urine.
  • Staphylococcus aureus: Resistance to cefoxitin (which is indicative of MRSA) in isolates from blood and samples from skin and soft tissue was below 2%, to compare with the number of reported MRSA from blood 2019: 72.
  • Enterococcus faecalis and Enterococcus faecium: Vancomycin resistance in isolates from blood remains low (0.1 and 1%, respectively) and the high-level aminoglycoside resistance decreases.
  • 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 and pigs. 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 low, and the situation is favourable in an international perspective.

Title

Published

 
Swedres-Svarm 2018 (pdf)* 2019  
Swedres-Svarm 2017 (pdf) 2018  
Swedres-Svarm 2016 (pdf) 2017  
Swedres-Svarm 2015 (pdf) 2016  
Swedres-Svarm 2014 (pdf) 2015  
Swedres-Svarm 2013 (pdf) 2014  
Swedres-Svarm 2012 (pdf) 2013  
Swedres-Svarm 2011 (pdf) 2012  
Swedres-Svarm 2010 (pdf) 2011  
Swedres-Svarm 2009 (pdf) 2010  
Swedres-Svarm 2008 (pdf) 2009  
Swedres-Svarm 2007 (pdf) 2008  
Swedres-Svarm 2006 (pdf) 2007  
Swedres-Svarm 2005 (pdf) 2006  
Swedres-Svarm 2004 (pdf) 2005  
Swedres-Svarm 2003 (pdf) 2004  
Swedres-Svarm 2002 (pdf) 2003  
Swedres-Svarm 2001 (pdf) 2002  
Swedres-Svarm 2000 (pdf) 2001  

*One figure (3.31) in the printed report Swedres-Svarm 2018 is incorrect. The figure has been corrected in the PDF file that is accessible online.