OBJECTIVETo investigate the effects of the different treatment on gut flora in patients with rectal cancer in the perioperative period.

METHODSA total of 64 patients with rectal cancer were prospectively enrolled from July 2010 to June 2011 at the Qingdao University Medical College Affiliated Hospital, and randomized into 8 groups receiving different treatments in perioperative period. Factorial design was used to study three factors including preoperative bowel preparation, antibiotics use, and postoperative fasting. Patients were randomized into 8 groups with 8 patients in each group using the random digit table. Preoperative and postoperative stool specimens were collected and diluted, which were transferred to selective medium. Bacteria counts were calculated after 48 hours of culture under constant temperature. The changes in gut flora between the different groups were compared.

RESULTSCompared to the preoperative parameters, total bacteria, Bifidobacterium, Peptostreptococcus, Lactobacillus, Bacteroides, Enterococcus decreased significantly(P<0.05), while the E.coli count increased significantly. The bacillus/coccus ratio was significantly imbalanced. Preoperative bowel preparation, oral antibiotics, and postoperative fasting were all predominant factors associated with gut flora(all P<0.05). Compared with the antibiotic restriction group, Bacteroides, Enterococcus, Lactobacillus, Peptostreptococcus, and total bacteria count were reduced significantly, and the bacillus/coccus ratio increased in the non-antibiotics restriction group(P<0.05). In the bowel preparation group, Bacteroides, Peptostreptococcus, total bacteria count, and the bacillus/coccus ratio decreased(P<0.05). In the postoperative fasting group, Bacteroides, Enterococcus, total bacteria, and bacillus/coccus ratio decreased(P<0.05).

CONCLUSIONSAntibiotics, bowel preparation, and postoperative fasting can affect the number and ratio of gut flora in patients with rectal cancer in the perioperative period, leading to dysbacteriosis.