Gerek toplum kaynaklı gerekse hastane kaynaklı üriner sistem infeksiyonlarında en sık izole edilen etken Escherichia coli'dir. Bu çalışma, bölgemizdeki Escherichia coli suşlarının çeşitli antibiyotiklere direnç durumlarının belirlenmesi ve ampirik tedavi seçeneklerinde yol gösterici olması amacıyla yapılmıştır. 129 toplum kökenli, 120 hastane kökenli susun, "National Committee for Clinical Laboratory Standards (NCCLS)" önerilerine uygun olarak Kirby-Bauer disk difüzyon yöntemi ile antibiyotik duyarlılıkları belirlenmiştir. Hastane kökenli suşlar tüm antibiyotiklere daha dirençli olup, her iki epidemiyolojik grupta da en dirençli görülen antibiyotiğin ampisilin (%48.8 - %83.3), en az dirençli görülen antibiyotiğin ise amikasin (%0.8 - %4.2) olduğu saptanmıştır. Trimetoprim-sülfametoksazol (TMP-SMX) direnci, toplum ve hastane kaynaklı Escherichia coli suşlarında sırasıyla, %39.5 ve %65.0, sip-rofloksasin direnci ise, %16.3 ve %38.3 olarak bulunmuştur. Bölgemizdeki toplum kökenli üriner sistem infeksiyonlarının da ampirik tedavisinde TMP-SMX'in tercih edilmemesi gerektiği görülmüştür The Antibiotic Resistance of Escherichia coli Strains Isolated From Urine Specimens From Hospital and community Originated Urinary Tract Infections The most frequently isolated agent both from community and hospital originated urinary system infections is Escherichia coli. The aim of this study was to determine the resistance states of Escherichia coli species to various antibiotics and to direct empirical treatment choices in our city. The antibiotic sensitivities were determined in 129 community originated and in 120 hospital-originated species by Kirby-Bauer disc diffusion method, which was relevant with National Committee for Clinical Laboratory Standards (NCCLS). The hospital-originated species were found to be more resistant to all antibiotics. The antibiotic with the most frequent resistance was ampicillin (48.8%-83.3%) and with the least frequent resistance was amikacin (0.8%-4.2%) in both epidemiologic groups. Trimethoprim-sulfamethoxazole (TMP-SMX) resistance was found in 39.5% and 65.0% of species originated from community and hospital, respectively. Ciprofloxacin resistance were found 16.3% and 38.3% of species originated from community and hospital, respectively. In conclusion, we considered that the use of TMP-SMX shouldn't be recommended in empirical treatment of urinary tract infections originated from community.