| The digestive system is home to trillions of microorganisms, living more than500bacteria species. The colon may have bacterial counts that approach1011～1012cfu/g of content. Most of the bacteria in the gut are anaerobes, only less than1%are facultative anaerobes, obligate aerobes and microaerobes. The whole surface of the digestive system in a healthy gut flora is covered and dominated by beneficial bacteria, such as Bifidobacterium and Lactobacillus. The beneficial bacteria are the housekeepers of the gut, they provide a natural barrier and protect us against all sorts of invaders, bacteria, parasites, fungi, viruses, toxins etc. They also produce substances like antibiotic that dissolve viruses and ’bad’ bacteria, reduce pH near the wall of the gut making it uninhabitable for the ’bad’ bacteria to colonise. If the population of the beneficial flora is damaged and not functioning well, the pathogenic bacteria, such like Escherichia coli, Enterococcus and Staphylococci, can adhere to the surface of the mucosal epithelium and break out into the bloodstream, causing bacteria translocation or chronic disease and even cancer.Dysbacteriosis is one of the major causes of enterogenic infection. There are many factors today that damage the beneficial gut flora. Surgical trauma, antibiotics, postoperative fasting, water deprivation and long-term parenteral nutrition all have a devastating effect on intestinal mucosa barrier. They can destroy gut microecology environment that causing beneficial bacteria dysfunction, which help opportunistic flora begin to copy into a large population, and probiotic bacteria growth is obviously below the normal range. If there is not given any interventions to control the progress of dysbacteriosis, it certainly will inevitably result in bacteria or endotoxin translocation. On the basic of the primary disease, bacteria translocation will lead to a second strike to the human body, contributed to enterogenic infection and systemic inflammatory response syndrome (SIRS), even causing multiple organ dysfunction syndrome(MODS).The purpose of preoperative mechanical bowel preparation (MBP) is to reduce the risk septic complications and anastomotic dehiscence. The traditional bowel preparation requires patients having antibiotics and laxatives at the first day they are admitted to hospital, therefore, it will effectively achieve the aim of bowel cleansing and easily control surgical site infection (SSI). However, excessive antibiotic use can disrupt the balance of beneficial intestinal bacteria and can lead to digestive disturbances and recurrent infections. In addition, repeated cleansing enema will cause dehydration, electrolyte imbalance and malnutrition and reduce patients’ surgical tolerance. High pressure countercurrent washing will stimulate the metastasis of neoplasm. Meanwhile, mucosal hyperemia and edema can aggravate gut micro ecology damage, increasing the pathogenic bacteria growth and reproduction, finally it will cause enterogenous systemic infections. So far, a number of studies have shown dysbacteriosis involved in the development of many gastrointestinal diseases. Patients with intractable diarrhea, unexplained low fever and intra-abdominal infection after colorectal recession, possibly associated with preoperative antibiotics and mechanical bowel preparation.Therefore, we conducted a prospective study to assess the impact of different bowel preparations on changes of intestinal flora in the patients following colorectal resection. Simultaneously we analyzed the influential factors of dysbacteriosis and the relationship between dysbacteriosis and postoperative enterogenous systemic infections, which would further guide us to handle the perioperative treatment, avoiding serious dysbacteriosis after operation.MATERIALAND METHOD1. General informationsThese experimental objects were chosen from the60patients with colorectal cancer who had been operated with a curative intent in Nanfang hospital from Mar2010to Mar2011. Inclusion criteria:①Pathological diagnosis was colorectal cancer;②Patients were generally in good condition, without severe heart, lung, kidney and liver dysfunction or metabolic diseases, the tumor was not found to distant metastases;③Complications of severe intestinal obstruction, bowel perforation and enteritis were not happened in the patients, they neither have preoperative chemotherapy or radiotherapy as well.According to different bowel preparations,60patients were randomly divided into control group (27cases) and experimental group (33cases). Control group were performed three days bowel preparation, whereas experimental group were performed only one day bowel preparation. One surgeon performed all operations. In control group,13were male and14were female, the mean age was54.96±1.87. Surgical procedure:10were right hemicolectomy,4were left hemicolectomy,4were sigmoidectomy,6were Dixon’s and3were Mile’s. TNM stage of tumor:Ⅰ for5cases, Ⅱ for12cases, Ⅲ for10cases. The average operating time was2.12±0.09hours. The mean blood loss was109.63±8.05ml. In experimental group,19were male and14were female, the mean age was58.21±1.36. Surgical procedure:11were right hemicolectomy,4were left hemicolectomy,6were sigmoidectomy,5were Dixon’s,4were Mile’s and3were Hartmann. TNM stage of tumor:Ⅰ for8cases, Ⅱ for8cases, Ⅲ for17cases. The average operating time was2.08±0.08hours. The mean blood loss was110.91±7.86ml. There were no significant differences of patients’age, gender, surgical procedure, operating time, blood loss and Dukes stage in both groups. This investigation was approved by Medical Ethics Committee, and all patients in both groups voluntarily joined this study with informed consents.2. MethodsControl group:①Patients had half liquid diets rich in nutrient3days before operation, whole liquid diets1day before operation.②Prophylactic antibiotics (gentamycin8wu, metronidazole0.4g,3times a day) were given orally to all patients3days before operation.③Lactulose oral solution (30ml/d) was given the first day of admission.④MBP was performed respectively at8p.m. the day before surgery and the early moring of preoperation.Experimental group:①Patients were allowed to have a normal oral intake during the day before surgery, while liquid diets1day before operation.②Prophylactic antibiotics (gentamycin8wu, metronidazole0.4g,3times a day) were given respectively to all patients at8a.m.12a.m. and4p.m.the day before operation.③Sodium solution (90g sodium and1000m15%GNS) was given at6p.m. the day before surgery.④MBP was not given before operation.Antibiotics (cefotiam2g) were given intravenously to all patients after induction of anesthesia.Postoperative management:Prophylactic antibiotics (cefamandole2g, metronidazole1.5g) were given intravenously to all patients for3days after operation. Total parenteral nutrition (Kabiven TM PI1440ml) were used for3days, and all the patients maintained transfusion for7days. Energy intake was1500to2000kcal for each day. Postoperative fasting for2to3days, patients could had a normal oral feeding after defecation.3. Observe gauges(1) Bacteria cultivationFresh feces were collected before bowel preparation and the first defecation after surgery, and sample submitted in30minutes. Each tube had0.5g fresh dejection and4.5ml diluent, making a series of10times diluted. Each dilution was taken10μl, respectively inoculated in10kinds of selective medium plate. The mediums were as follows:escherichia coli, enterococcus, staphylococcus, saccharomycetes, bacteriod, bifidobacterium, lactobacillus, peptococcus anaerobius, eubacterium and small spindle bacteria. Aerobe cultured for24hours on37℃, anaerobic cultured for72hours on37℃. The bacterial strains count and species identification were carried out with the method of plate counting live bacterium.(2) Postoperative complicationsPatients’ clinical outcome would be discused in the study, endpoints were diarrhea, anastomotic leakage, surgical site infection, intra-abdominal infection, pulmonary infection and pseudomembranous colitis.4. Statistical analysisApplication of SPSS13.0statistical analysis software for statistical analysis with hypothesis testing level a=0.05. Measurement data show in (x±s). Significance between two independent simples was determined by the Independend-Samples t-test. Significance between paired simples was determined by Paired t-test. The analysis of dysbacteriosis was perform by the Independend-Samples Nonparametric Test and Related-Samples Nonparametric Test. And the postoperative complications between the sample groups were performed with Fisher’s exact probability test. Difference were considered siginificant when P<0.05.RESULTS1. Patients with colorectal cancers had dysbacteriosis in different degrees. The population of beneficial bacteria, such as bifidobacterium and lactobacillus, dropped evidently, but opportunistic flora growth was obviously increased.2. Intestinal flora disturbance was found in both groups. The postoperative population of Escherichia coli and staphylococcus were much higher than preoperative, while bifidobacterium and lactobacillus decreased significantly (P<0.05), which happened more obviously in the control group (P<0.05).3. There were no significant differences of population distribution in both groups before bowel preparation, but having a great change in the degree of dysbacteriosis after operation, which showed patients in experimental group develop less seriously (P=0.031). No siginificant differences were found in experimental group during pre and post operation (P=0.739), but patients in control group developed more seriously than preoperation (P<0.001)4. Anastomotic leakage did not happen in both groups. In experimental group, three patients (9.09%) developed wound infection, six patients (18.18%) occurred in diarrhea. In control group, the overall postoperative infection rate was29.62%, including surgical site infection (18.5%), intra-abdominal infection (7.41%) and pulmonary infection (3.7%). Four patients developed diarrhea, one of them happened pseudomembranous colitis. Postsurgical infection in both groups were statistically significant differences in this study (χ2=4.184, P=0.041), but there were no differences in the incidence of anastomotic leakage and diarrhea.(χ2=0.121, P=0.728).CONCLUSIONS1. Medium to light intestinal flora disturbance was found in both groups, which showed that the number of probiotics was lower than pathogenic bacterias, and the ratio of bifidobacterium and colibacillus was upside down.2. Mechanical bowel preparation could damage the intestinal mucosal epithelium, and prophylactic antibiotics over-dose application would kill most of the gram negative bacilli, which would lead to intestinal microecology dysfunction and adverse to get a fast recovery from illness.3. Fast bowel preparation caused a less jamming effect on intestinal flora disturbance. And it showed no statistically significant difference in the incidence of anastomotic leakage and diarrhea, but a higher occurring rate of enterogenic infection, comparing with tranditional bowel preparation. Fast bowel preparation was safe, economical and reliable, and it would shorten the time of hospital stays, decreased the strength of colonic irrigation and caused a less intestinal barrier damage, which may have a positive effect on the postoperative recovery, state of nutrition and intestinal flora reconstruction. |
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