Bacteriological Study of Urinary Stones

Background: Despite modern antibiotic therapy and technological advances in lithotripsy, the presence of infection in patients with urinary stones, as well as with infectious stones is still a significant cause of morbidity and mortality. Recent findings lend more theories as to how infection leads to stone formation.
Aim: The bacteriological study of urine and stone samples from patients with urinary tract infections (UTI) and the correlation of the bacteriological analysis results of stones and urine culture.
Method: We enrolled patients admitted to the urology department of Mures Emergency Hospital, from December 2008 to March 2009; all 50 patients who were diagnosed by the urologist as having urinary stones were included in this study. Bacteriological study was conducted on pre-operative urine and operated renal stones. Pre-operative urine sam¬ples were collected aseptically for macroscopic and micro¬scopic examination. Both pre-operative urine and operated renal stones were processed for bacteriological culture. The isolated microorganisms were identified by standard techniques.
Results: From the 50 patients included in this study, 20 had both infected stones and UTI. While correlating the results of bacteriologi¬cal analysis of stones and urine culture, the same microorganisms from urine culture and stone culture were isolated in 12 (60%) out of 20 cases, but different microorganisms in 8 (40%). The bacteriological study of urine and stone samples revealed that the most common pathogens were E.coli, Pseudomonas aeruginosa.
Conclusion: The incidence of infectious urinary stones in patients with UTI was higher than in the sterile ones. The preponderant identified microorganisms were E. coli, followed by Pseudomonas aeruginosa. In more than half of the cases, the same microorganisms were found both in UTI and within the urinary stones.