engleski

Restriction of amoxicillin/clavulanate use : the impact on overall antibiotic consumption and on antimicrobial resistance

Introduction: Amoxicillin/clavulanate has been for years the most prescribed antibiotic in Clinical Hospital Osijek, used mostly for empirical therapy. Such an irrational use resulted in high percentage of Enterobacteriacae strains resistant to amoxicillin/clavulanate and Hospital Drug Committee has restricted its use to isolates with proven sensitivity to amoxicillin/clavulanate. Recently Helfland (2003) and Thomson (2006) have described mechanism of resistance to beta lactamase inhibitors. Aims: Restriction of amoxicillin/clavulanate use was expected to to decrease the emerging bacterial resistance to the drug. Methods: Restriction of amoxicillin/clavulanate use started in October 2006. We collected hospital data on antibiotic consumption and antibiotic resistance in two 3-month periods before and after the intervention: August–October 2006 and November 2006–January 1007. We also collected monthly data on antibiotic consumption in 6-month period from August 2006 to January 2007. Results: Before the intervention amoxicillin/clavulanate consumption accounted for 28.73% of overall antibiotic consumption. The overall antibiotic consumption fell from 50.57 DDD/100 patient-days in the first 3-month period to 41.50 DDD/100 patient-days in the second period after the intervention. Reduction of amoxicillin/clavulanate use (from 14.56 to 1.80 DDD/100 patient-days) was followed by rise of cefuroxime use (from 5.82 to 9.25 DDD/100 patient-days). Amoxicillin use rose from 2.05 to 3.06 DDD/100 patient-days. Fluoroquinolone use did not increase (4.57 DDD/100 patient-days in the first period and 3.93 in the second) (Figure 1 and 2). In E.coli isolates, the resistance to amoxicillin/clavulanate fell from 39.87% in first 3-month period to 12.59% in the second. In Klebsiella pneumoniae isolates, the resistance to amoxicillin/clavulanate fell from 52.63 to 29.41% and in Klebsiella spp it rose from 33.33 to 43.59%. In ESBL producing Klebsiella pneumoniae isolates the resistance to amoxicillin/clavulanate fell from 100 to 66.67% and in ESBL producing Klebsiella spp it fell from 71 to 45.6% (Table 1). Resistance of E.coli to amoxicillin fell from 66.46 to 60.83% and resistance of all Klebsiella isolates to amoxicillin remained 100%. Conclusion: Restriction of amoxicillin/clavulanate use has caused increased cefuroxime and amoxicillin use and reduction of overall antibiotic use. Although the fluoroquinolone use was no longer restricted, its use did not rise. In 3-month period after the intervention, resistance of E.coli, Klebsiella pneumoniae and ESBL producing Klebsiella pneumoniae and Klebsiella spp to amoxicillin/clavulanate significantly decreased. Resistance of named bacteria to amoxicillin did not change significantly so we conclude that the increasing sensitivity to amoxicillin/clavulanate was caused by decreasing resistance to beta lactamase inhibitor.

antibiotic consumption, antibiotic resistance, ESBL bacteria

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