Ans. d (> 1,00,000) (Ref. H-18th, Chapter 288; Ananthanarayan Microbiology 7th/pg. 276)Hass and other investigators have established that in the presence of active infection in the urinary tract the urine will contain 1,00,000 or more/mL. The level is, therefore, considered to represent significant bacteriuria.SIGNIFICANT BACTERIURIA# Counts of 10,000 or less/mL are due to contamination during voiding and are of no significance.# In most instances, growth of >105 organisms per milliliter from a properly collected midstream "clean-catch" urine sample indicates infection - significant bacteriuria.# When carefully sought by chamber-count microscopy, pyuria is a highly sensitive indicator of UTI in symptomatic patients.# Pyuria is demonstrated in nearly all acute bacterial UTIs, and its absence calls the diagnosis into question.# The leukocyte esterase "dipstick" method is less sensitive than microscopy in identifying pyuria but is a useful alternative when microscopy is not feasible.# Pyuria in the absence of bacteriuria (sterile pyuria) may indicate infection with unusual agents such as C. trachomatis, U. urealyticum, or Mycobacterium tuberculosis or with fungi.# Alternatively, sterile pyuria may be documented in noninfectious urologic conditions such as calculi, anatomic abnormality, nephrocalcinosis, vesicoureteral reflux, interstitial nephritis, or polycystic disease.