gms | German Medical Science

Background: Current regional antibiotic susceptibility data from hospitalized patients and outpatients are needed to support local networks for the defence against the spreading of multiresistant bacteria. This study monitors the development of antibiotic resistance rates in Thuringia from 2007 to 2012.

Material and methods: Results of routine susceptibility data for twelve antibiotic agents of a total of about 160,000 isolates of Staphylococcus aureus (n=40,971), Escherichia coli (n=69,459), Pseudomonas aeruginosa (n=12,932), and Enterococcus faecalis (n=38,983) from seven Thuringian microbiology laboratories were analyzed retrospectively for the years 2007 to 2012. Susceptibility testing was performed by agar diffusion test or breakpoint-testing according to the German standard DIN 58940 or EUCAST guidelines. The results were compared to nationwide German data published online by the Robert Koch Institute on the Antibiotic Resistance Surveillance website (ARS, https://ars.rki.de).

Results: Resistance rates of S. aureus, E. coli, and P. aeruginosa from outpatients were significantly lower than those from hospitalized patients. The rate of methicillin resistant S. aureus (MRSA) in outpatients rose from 6.9% in 2007 to 9.6% in 2012, whereas the MRSA rate remained constant at around 15.0% in small (<500 beds) and showed a slight increase from 16.3% to 17.7% in large (>500 beds) hospitals. The resistance rate of E. coli against cefotaxime as a marker for extended spectrum betalactamase (ESBL) increased from 2007 to 2012 with a stronger rise in outpatients (fivefold, from 1.3% to 6.9%) than in hospitals (from 8.3% to 14.1%). Resistance rates of P. aeruginosa against ciprofloxacin decreased from 2007 to 2012 in hospitalized patients (from 14.8 % to 10.1%). E. faecalis isolates remained highly susceptible to ampicillin.

Conclusions: In 2012 Thuringian MRSA rates remained well below nationwide levels as determined by the ARS. However, an alarming increase of ESBL rates was observed both in outpatients and hospitalized patients, with regional rates significantly higher than ARS rates in 2012.