| Objective:Infection is the most common complication in patients with malignant tumors and an important cause of death. According to statistics, 60% to 70% of the leukemia / lymphoma died of infection. Children with malignant tumors are often prone to bacterial infections, bacteremia and other complications during the chemotherapy period, so it could be worse and even dead.Therefore the pediatric physicians must face the difficulty to find out the pathogens which caused infection.The intestine is the body's largest repository of bacteria and endotoxin, under normal circumstances, the body and the normal flora maintain the dynamic micro-ecological balance.The normal intestinal flora play an important role in the maintenance of intestinal structure and function.The obligate anaerobes dominate by bifidobacteria combin with the specific receptors on the intestinal mucosal surface to form a fairly stable biofilm structure, can be effective against bacterial invasion of the body.Once this ecological balance is damaged, A lot of bacteria and endotoxin into the systemic circulation by the portal system and cause intestinal endotoxemia and bacterial translocation vertical, under certain conditions, it can also stimulate a chain reaction of the cytokines and other inflammatory mediators and cause systemic organ damage. Therefore, quantitative analysis of intestinal flora can help to understand the influence degree of cancer chemotherapy drugs on the intestinal microflora in children with cancer ,and then on the micro-ecological point to analysis the relationship between chemotherapy drugs and intestinal flora, furthermore to provide the help for the clinical to judgment children's condition and prognosis, and provide the basis for the prevention and treatment of Microbio-ecologics in infectious diseases.Microbioecologics are something that base on micro-ecological principl- es,by adjusting and maintaining the balance of micro-ecological environment to improve the health of host. including probiotic bacteria and their metabolites products and growth-promoting factors. Microbioecologics can directly add the body's nomal flore or selectively stimulate the growth of some flora,which can competitively inhibit the exogenous and endogenous pathogenic bacterias overgrowth and colonization, furthermore to effectively prevent the occurrence and development of endogenous infection. Currently in clinical, microbioecologics are mainly used in diarrheal diseases and liver diseases.At present,related studies about the influence of chemotherapy on the state of intestinal flora and the prenvention of microbioecologics are very rare. In this study ,by 16S rRNA/DNA real-time fluorescence quantitativePCR to quantitatively detect the Bifidobacteria and Escherichia in the fecal samples from children with malignant tumors at differente degree of myelosuppression , and then compare with the healthy group and intervention group to learn the impaction of chemotherapy diugs on the Bifidobacteria and Escherichia coli,learn the influence of microbioecologics on the balance of intestinal flora,furthermore to discuss the preventive effect of microbioecologics in keeping the balance of of intestinal flora and use this function to reduce or mitigate the occurrence of intestinal infections during the chemotherapy period,and so to ensure the smooth implementation of chemotherapy ,improve the therapeutic level ,extend children's survival time.Methods:1 Subjects 40 children with malignant tumors were selected from the depertment of pefiatric, Fourth affiliated Hospital of Hebei Medical University and Children's Hospital of Hebei Province who were divided into two groups randomly:observation group(the average age7.2±1.5years, male:female l:1.12,n=20) and intervention group(the average age7.0±1.5years, male:female l:1.15,n=20) ,and randomly selected 20 normal children in a primary school as a healthy control group(the average age6.9±1.2years,male:female l:1.12,n=20). Patients in intervention group started to oral Golden Bifid at the bengining of chemotherapy and ended when the myelosuppression up to four degree.The age and gender of children in these three group showed no differences(P> 0.05).2 Samples stool samples were collected when children at different degree of myelosuppression, No rear -80℃refrigerator for use.2.1 Preparation of bacterial DNA According to the instructions on the box cxtraction of bacterial DNA to extrac the DNA in fecal samples and standard strains .2.2 Conventional PCR reaction ,qualitative analysis of the bacteria DNA extracted .2.3 Real-time fluorescence quantitative PCR ,melting curve drawn,making the standard curve and quantitative analysis.Results:1 The number of Bifidobacterium in stool specimens from control group,observation group and intervention group . in control group , the number of Bifidobacterium was 9.23±0.59, observation group 0,Ⅱ,Ⅳgrade of myelosuppression , the number of bifidobacteria were 7.26±0.41,4.33±0.66,4.18±0.31 respectively; intervention group, 0,Ⅱ,Ⅳgrade of myelosuppression ,the number of bifidobacteria were 7.18±0.44,6.16±0.26,6.21±0.21 respectively. Compared with control group, the number of bifidobacteria in observation group and intervention group 0 grade of myelosuppression were significantly reduced, had significantly different (P<0.05); compared between observation group and intervention group 0 grade of myelosuppression,the number of Bifidobacterium had no significant difference (P> 0.05); compared between observation group and intervention groupⅡ,Ⅳgrade of myelosuppression , the number of bifidobacteria had significantly different (P <0.05).2 The number of Escherichia coli in stool specimens from control group,observation group and intervention group . in control group , the number of Escherichia coli was 7.44±0.48, the observation group 0,Ⅱ,Ⅳgrade of myelosuppression , the number of Escherichia coli were 6.65±0.30,3.92±0.46,4.01±0.21 respectively; intervention group, 0,Ⅱ,Ⅳgrade of myelosuppression ,the number of Escherichia coli were 6.68±0.52,4.09 ±0.19,4.16±0.18 respectively. Compared with control group, the number of Escherichia coli in observation group and intervention group 0 grade of myelosuppression was significantly reduced, had significantly different (P <0.05); compared between observation group and intervention group 0 grade of myelosuppression,the number of Escherichia coli had no significant difference (P> 0.05); compared between observation group and intervention groupⅡ,Ⅳgrade of myelosuppression , the number of Escherichia coli had significantly different (P <0.05).Conclusion:1 Compared with healthy children ,the number of intestinal Bifidobacterium and Escherichia coli in infant with malignant tumors before chemotherapy was reduced,suggesting that there is a certain imbalance of intestinal flora in children with malignant tumors before chemotherapy.2 During the period of chemotherapy, the number of intestinal Bifidobacteri- um and Escherichia coli was further reduced , suggesting that chemotherapy drugs can inhibt the growth of normal intestinal flora and increase the imbalance of intestinal flora.The most obvious inhibition appeared at theⅡgrade of myelosuppression.3 Microbioecologics can significantly improve the number of intestinal Bifidobacterium and Escherichia coli in infant with malignant tumors during the process of chemotherapy, foster the growth of normal intestinal flora ,and adjust the imbalance of intestinal flora. |
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