Gerova V., V. Nakov, L. Tankova, P. Penchev, R. Nakov PREVALENCE AND ANTIBIOTIC TREATMENT OF SMALL INTESTINAL BACTERIAL OVERGROWTH IN PATIENTS WITH CROHN’S DISEASE Gerova V., V. Nakov, L. Tankova, P. Penchev, R. Nakov Clinical Center of Gastroenterology, Queen Joanna Hospital, Medical University, Sofia, Bulgaria INTRODUCTION Small intestinal bacterial overgrowth (SIBO) sometime complicates the clinical course of Crohn’s Disease (CD) but its treatment is not clearly defined. AIM To evaluate the prevalence of SIBO in patients with CD аnd to assess the efficacy and compliance of Ciprofloxacin and Metronidazole treatment in cases with SIBO by using a lactulose breath hydrogen test (LHBT). PATIENTS AND METHODS Thirty six unselected adult patients (17 females, 19 males; mean age 32,7) with CD and 10 healthy subjects (4 females, 6 males; mеan age - 34,5) consented to participate in the study. Eight of the patients had undergone an ileocolic resection, but the others were non-operated. LBHT was performed in all patients and healthy subjects. After an oral dose of 10 g lactulose dissolved in 100 mL tap water, breath hydrogen (H2) concentrations were recorded every 15 min for 120 min using a H2 breath analyzer (Gastrolyzer Breath Hydrogen Bedfont Scientific, UK). The results were expressed in parts per million (ppm). The test was considered as positive on the basis of the following criteria: the baseline value of exhaled H2 ≥ 20 ppm and an increase of more than 12 ppm over baseline after oral application of lactulose in at least three samples within the measurement period. Patients with positive LHBT were treated with Ciprofloxacin (400 mg b.i.d.) and Metronidazole (1500 mg t.i.d.) for 10 days and the test was performed repeatedly. Compliance and the side-effect incidence were also evaluated. Fig. 1. Mean basal exhaled H2 (ppm) of patient and control groups The mean basal breathed H2 in CD patients with evidence of SIBO (37,112,86 ppm) were significantly (p<0,001) reduced (10,671,58 ppm) after antibiotic treatment (Figure 2). Fig. 2. Mean basal exhaled H2 (ppm) of patients with SIBO before and after antibiotic treatment SIBO eradication was achieved in all except one (88.9%) of patients (Figure 3). No adverse effects were observed. RESULTS The patients with CD were with significantly (p<0.05) higher basal breathed H2 (14,64  1,07 ppm; range: 3-51) in comparison to healthy subjects (5,56  0,96 ppm; range: 2-12) (Figure 1). Out of 36 CD patients, SIBO was documented in 9 (25,0%) but in none of the healthy subjects (p<0,05). The prevalence of SIBO was significantly (p<0,05) higher in patients with previous surgery 5/8 (62,50%) than in patients without of surgery 4/26 (15,38%). Fig. 3. Basal exhaled H2 (ppm) of patients with SIBO before and after antibiotic treatment CONCLUSIONS SIBO is a frequent condition in CD patients especially in the cases of previous ileocolic surgery. Short-term administration of Ciprofloxacin and Metronidazole was well tolerated and is effective treatment of these patients. The LBHT is simple, noninvasive, inexpensive and repeatable method for diagnosing and monitoring the SIBO in CD patients. Future extensive trials are needed to establish the exact role of these alterations in CD patients.