No 42-43 - 2012

DANMAP 2011: Antimicrobial consumption and resistance

The annual DANMAP report (Danish Integrated Antimicrobial Resistance Monitoring and Research Programme) summarises the Danish consumption of antimicrobial agents used for animals and humans and follows the development of resistance in bacteria collected from animals, food and humans. The 2011 DANMAP report is available at www.danmap.org. This EPI-NEWS outlines some of the main characteristics concerning consumption and resistance development in humans, as presented in the 2011 DANMAP report.

Total antimicrobial consumption

In 2011 the total consumption of antimicrobial agents for systemic use in humans (primary health care and hospitals in total) remained at the same level as in 2010 but still following the generally increasing trend observed during recent years. Primary health care accounted for 90% of the total consumption. From 2002 to 2011, the total consumption of antimicrobial agents in Denmark increased by 28%.

Antimicrobial consumption in primary health care

In 2011 the consumption of antimicrobial agents in primary health care was at the same high level as in 2010. The high consumption levels during 2010 and 2011 correlated with Mycoplasma pneumoniae outbreaks, EPI NEWS 48/10 and 42-43/11. Part of the increased antimicrobial consumption (particularly macrolides) is most likely directly related to these outbreaks.

Other explanations for the increased consumption of antimicrobial agents are presently difficult to assess due to a lack of disease-specific indication codes on prescriptions. The availability of such indication codes is expected to improve in future as in 2012 it was decided to discontinue the broad indication codes ("against inflammation" and "against infection") and replace them with more specific indication codes on all Danish antimicrobial prescriptions. From 2002 to 2011, the total consumption of antimicrobial agents in primary health care increased by 29%, and the consumption of broad-spectrum antimicrobial agents increased by 78% (expressed as DDD/1,000 inhabitants per day, DDD = Defined Daily Doses).

Antimicrobial consumption in the hospital sector

The total antimicrobial consumption in the entire hospital sector (rehabilitation centres, hospices & private, psychiatric, specialized and somatic hospitals) decreased by 3.7% from 2010 to 2011. Since 2002, the consumption has increased by 26%. From 2001 to 2011, the use of broad-spectrum antimicrobial agents in hospitals has increased by 67%.

Resistance occurrence in zoonoses

As in previous years, the occurrence of resistance to several of the tested antimicrobial agents, including ciprofloxacin, was higher in patients with Salmonella Typhimurium and Campylobacter jejuni infections acquired abroad than in patients with infections acquired in Denmark.

Further information on resistance

The number of new MRSA cases increased to 1,292 in 2011, compared to 1,097 cases recorded in 2010. The increase seen in 2010, EPI-NEWS 46/11, thus continued through 2011. The increase was primarily observed in non-hospitalised cases (community-acquired cases). The number of hospital-acquired cases was low and only accounted for 5% of the total number of cases. 

In 2011, 164 new human cases of CC398 MRSA (an MRSA type associated with contact to pigs) were detected. In 14 of these cases, no direct or indirect contact to pigs could be established. In 2011, the occurrence of resistance to 3rd generation cephalosporins in both Klebsiella pneumoniae (10%) and Escherichia coli (8%) from blood isolates corresponded to that observed in 2010. In comparison, the occurrence of resistance in 2006 was below 5% for both types of bacteria.

In October 2011, 12 of the 13 departments of clinical microbiology in Denmark screened all E. coli and K. pneumoniae urine and blood isolates for ESBL production, EPI-NEWS 39b/12. The ESBL prevalence from 2011 was compared to data from corresponding studies performed in 2007 and 2009. From October 2009 to October 2011, the prevalence of ESBL-producing E. coli increased significantly in urine samples collected in both primary health care (from 2.3% in 2009 to 3.2% in 2011) and hospitals (from 3.8% in 2009 to 4.7% in 2011).

During 2008–2011, a total of 15 carbapenemase-producing enterobacteria (CPE) were recorded in Denmark. Of these, ten cases were found in 2011, the majority of which were imported from Libya in patients who were sent for hospital treatment in Denmark during the Libyan conflict, EPI-NEWS 10/12. Laboratory notification of CPE is not mandatory in Denmark and the real number of cases may therefore be higher than recorded.

In 2011, the occurrence of penicillin and erythromycin resistance among Streptococcus pneumoniae, and group A, B, C and G streptococci remained low. In contrast, ampicillin resistance was high (93 %) in Enterococcus faecium isolates from blood, while the occurrence of vancomycin resistance was low (1.3%) for E. faecium isolates. None of the tested E. faecalis isolates from blood were vancomycin resistant.

Commentary

Apart from the Mycoplasma pneumoniae outbreaks in the winters of 2010 and 2011, it is difficult to explain the increase in antimicrobial consumption observed in primary health care. Introduction of more disease specific indication codes on antimicrobial prescriptions from 2012 onwards will greatly facilitate the explanation of consumption changes observed for general practitioners and specialists.

An increased risk of infection with resistant Salmonella and Campylobacter infections in patients travelling abroad was observed. Ciprofloxacin-resistant bacteria may be associated with an increased risk of treatment failure, and it is therefore essential to consider any travel activity before initiating treatment.

The low occurrence of hospital-acquired MRSA shows that Danish guidelines for preventing MRSA infections are effective. However, the continued increase in the number of community-acquired MRSA infections, which has also been observed in other Nordic countries, is probably associated with travelling activity and subsequent spreading in the community. Furthermore, MRSA associated with pigs continues its increasing trend, although, despite the occurrence of a few suspected non-livestock associated cases, there are no indications of a spread to the general population. The Danish Health and Medicines Authority are expected to publish revised MRSA guidelines this autumn.

The increased consumption of broad-spectrum antimicrobials (ciprofloxacin, 2nd and 3rd generation cephalosporins and carbapenems) recorded at hospitals in recent years correlates with an increased occurrence of ESBL-producing E. coli from urinary tract infections. It is still unknown how the ESBL-producing bacteria spread, making it difficult to stop the spreading.

The increased occurrence of CPE in Europe and now also in Denmark is worrying. Not only are CPE infections extremely difficult to treat with antimicrobial agents, but the bacteria also carry the potential to establish and spread at hospitals as well as in the community. This corresponds to what was previously observed for ESBL-producing bacteria. Improved monitoring of ESBL-producing K. pneumoniae, E. coli and carbapenemase-producing bacteria is needed in Denmark.

(A.M. Hammerum, L. Skjøt-Rasmussen, K.G. Kuhn, S.S. Olsen, E.M. Nielsen, A.R. Larsen, A. Petersen, R.L. Skov, Microbiology and Infection Control, M. Laursen Dept. for Data Delivery and Medicinal Product Statistics).

Link to previous issues of EPI-NEWS 

24 October 2012