engleski

Improved antimicrobial susceptibility of uropathogenic Escherichia coli due to decline in ambulatory antibiotic consumption

OBJECTIVES: The aim of this study was to assess the impact of ambulatory antibiotic consumption on resistance patterns of Escherichia coli strains isolated from patients with community-acquired urinary tract infections (CA-UTIs) in Zagreb region. METHODS: All urinary specimens with significant bacteriuria processed during two study periods (January to October 2005 and January to December 2010) were included in the survey. Urinary specimens were collected in the course of routine diagnostics procedures of Zagreb outpatient population. Resistance patterns of 3052 E. coli strains collected during the first study period were compared with those of 4817 E. coli strains from the second study period. Antimicrobial susceptibility of isolates to commonly prescribed antibiotics was tested by disk diffusion method according to CLSI criteria. Information on ambulatory consumption of antibiotics, expressed in defined daily doses per 1000 inhabitants per day (DID), was obtained from annually published report by The Croatian Academy of Medical Sciences. RESULTS: In the period from 2001 to 2009, ambulatory consumption of broad spectrum penicillins, first generation of cephalosporins and co-trimoxasole declined from 4.09 DID, 1.65 DID and 1.70 DID in 2001 to 3.60 DID, 1.21 DID and 0.98 DID in 2009, respectively. While consumption of fluoroquinolones (FQs) remained more or less unchanged, usage of nitrofurantoin showed since 2007 constant increase. Considering the resistance of E. coli between 2005 and 2010, significant decrease in resistance was observed for amoxicillin (from 46.1% to 42.9% ; p=0.006), cephalexin (from 21.3% to 10.2% ; p<0.0001) and co-trimoxasole (from 28.9% to 23.3% ; p<0.0001). While resistance to nitrofurantoin remained very low in both study periods (2.4% in 2005, 2.1% in 2010), resistance to FQs significantly increased (8.6% in 2005, 12.0% in 2010 ; p<0.0001). CONCLUSION: Due to the updates in Croatian guidelines on empirical treatment of CA-UTIs, changes in ambulatory use of antibiotics occurred. Withdrawal of amoxicillin, cephalexin and co-trimoxasole from the list of first line agents for empirical treatment of uncomplicated cystitis, elicited significant improvement in susceptibility of uropathogenic E. coli to these antibiotics. Since no obvious rise in FQ use occurred, the increasing trend in FQ resistance which might be caused by the spread of highly epidemic FQ-resistant uropathogenic E. coli clonal groups requires further investigation.

Escherichia coli; urinary tract infections; therapy; antimicrobial resistance

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