Urol Res (2012) 40:455–460 DOI 10.1007/s00240-011-0449-8 123 ORIGINAL PAPER Quantitative analysis of colonization with real-time PCR to identify the role of Oxalobacter formigenes in calcium oxalate urolithiasis Ertan Batislam · Erdal Yilmaz · Ercan Yuvanc · Ozgul Kisa · Ucler Kisa Received: 7 July 2011 / Accepted: 20 December 2011 / Published online: 4 January 2012  Springer-Verlag 2012 Abstract The objective of the study was to quantitatively measure the number of Oxalobacter formigenes (O. formig- enes) colonizations in the gastrointestinal tract in calcium oxalate-forming patients with real-time polymerase chain reaction (PCR). Calcium oxalate-forming patients (n: 27) were included in the study. Serum calcium, sodium, potas- sium, urea and creatinine levels, as well as 24 h urine levels of calcium and oxalate were measured. The numbers of O. formigenes colonies in stool samples were detected by real- time PCR. One or two metabolic abnormalities were detected in 15 of 27 patients. The O. formigenes levels in patients with metabolic disturbance were signiWcantly decreased when compared to the patients with no metabolic abnormalities (p: 0.038). The undetectable levels of O. for- migenes were encountered in one of Wve patients with hypercalciuria, in three of four patients with hyperoxaluria and in four of six patients with both hypercalciuria and hyperoxaluria. In nine patients with a history of stone recurrence, O. formigenes colonization was signiWcantly lower than the patients with the Wrst stone attack (p: 0.001). O. formigenes formation ceased or signiWcantly diminished in patients with calcium oxalate stones with a coexistence of both hyperoxaluria and hypercalciuria. The measurement of O. formigenes colonies by real-time PCR seemed to be an inconvenient and expensive method. For this reason, the real-time PCR measurements can be spared for the patients with stone recurrences and with metabolic abnormalities like hypercalciuria and hyperoxaluria. The exact measure- ment of O. formigenes may also help more accurate pro- gramming of O. formigenes-based treatments. Keywords Calcium · Oxalate · Urolithiasis · Oxalobacter formigenes · Real-time PCR Introduction The majority of patients with urolithiasis had undergone wide operations and even had nefrectomies before the 1980s [1]. The morbidity decreased after the invention of extracorporeal disintegration techniques and Wne develop- ments of endoscopic surgery. The negative impact of these technological innovations has been the ignorance of the developments of medical therapies and preventive modali- ties. Surgery cures the stone; however, it does not eliminate the causes of the recurrences. Calcium oxalate stones recur 10% at 1 year, 35% at 5 years and 50% at 10 years, when left untreated after the primary treatment [1]. Numerous studies concluded that the modalities against the environmental and metabolic factors decreased the uri- nary stone recurrence rates [2, 3]. The cost of preventive measures has been far less than the hospital-based treat- ment cost of the stone. Selective medical therapies that tar- geted the formation of urolithiasis preclude invasive interventions in many individuals, and, particularly, diet alterations decrease recurrences. One of the most recent forms of diet modiWcations in the prevention of oxa- late-containing stones has been probiotics [4]. Oxalobacter E. Batislam · E. Yilmaz (&) · E. Yuvanc Faculty of Medicine, Department of Urology, University of Kirikkale, Tip Fakultesi, Uroloji AD, Saglik Sokak, 71100 Kirikkale, Turkey e-mail: erdaly69@mynet.com O. Kisa Department of Medical Microbiology, Gulhane Military Medical Academy and School of Medicine, Ankara, Turkey U. Kisa Faculty of Medicine, Department of Biochemistry, University of Kirikkale, Kirikkale, Turkey