Lab Manual and Workbook in Microbiology 11th Edition by Josephine Morello ,Paul Granato,Verna Morton

تمرين 14

A Case of Cystitis
A 21-year-old, sexually active female visited her family physician complaining of pain on urination (similar to a "burning sensation") and the production of foul-smelling urine. The physician suspected a urinary tract infection and ordered urinalysis and urine culture tests on a "clean-voided, midstream" urine sample. Urinalysis revealed the microscopic presence of greater than 40 white blood cells and 5 to 10 red blood cells per high-power field. In addition, on a dipstick test, the leukocyte esterase and nitrate reduction tests were both positive. A quantitative urine culture reported growth of greater than 100,000 gram-negative, lactose-fermenting bacilli per milliliter on MacConkey agar medium.
Which bacterium is most likely responsible for this patients infection?