肠道菌群失调诊断治疗建议

正常情况下,肠道菌群在体内与外部环境保持着动态平衡,并对人体的健康起着重要作用.如果这种平衡在某些情况下被打破,便形成肠道菌群失调(intestinal dysbacteriosis,ID),其表现为肠道菌群在种类、数量、比例、定位和生物学特性上的改变[1-4].临床上,引起肠道菌群失调的原因和疾病很多,常互为因果.主要表现是腹泻、便秘、腹胀、腹痛、消化不良等.肠道菌群失调对许多疾病的发生、发展和转归有重要影响.     

The role of normal flora in Giardia lamblia infections in mice

The presence of normal bacterial flora in the intestinal tract is thought to protect against colonization by pathogens. Only a few specific examples of this protection have been demonstrated for bacterial pathogens and protozoan infections. Mice from one commercial breeding farm were found to be less susceptible to infection with Giardia lamblia than were isogenic mice from another facility. When mice were housed together, resistance to infection was readily transferred to normally susceptible mice. After resistant mice were treated with neomycin, differences in susceptibility to infection were shown to be due to differences in the resident flora present in these mice. These results suggest the possible use of probiotic therapy for prevention of G. lamblia infections and may help explain some of the variability of outcomes seen in G. lamblia infections in humans.     

Alterations in intestinal microbial flora and human disease.

PURPOSE OF REVIEW: To highlight the evidence supporting the role of altered commensal gut flora in human disease. While the contribution of the indigenous gut microbial community is widely recognized, only recently has there been evidence pointing to indigenous flora in disease. RECENT FINDINGS: This review discusses recent evidence pointing to the role of altered commensal gut flora in such common conditions as irritable bowel syndrome and inflammatory bowel disease. Recent studies document the intricate relationship between the vast population of microbes that live in our gut and the human host. Since increased intestinal permeability and immune activation are consequences of an altered host-gut microbial relationship, what are the clinical effects of this shift in relationship? SUMMARY: We focus on the example of an abnormal expansion of gut microbial flora into the small bowel or small intestinal bacterial overgrowth and discuss the effects of bacterial overgrowth on the human host in acute pancreatitis, bacterial gastroenteritis, irritable bowel syndrome, inflammatory bowel disease, hepatic encephalopathy, and fibromyalgia and burn injury. The identification of the underlying role of altered commensal gut microbiota in these and other human diseases could lead to novel diagnostic and therapeutic strategies that would improve clinical outcome.     

Antimicrobial activity of Lactobacillus against microbial flora of cervicovaginal infections

ObjectiveTo assess the probiotic nature of Lactobacillus in preventing cervical pathogens by studying the effectiveness of antimicrobial activity against vaginal pathogens.MethodsLactobacilli were isolated from healthy vaginal swabs on selective media and different pathogenic bacteria were isolated by using different selective media. The Lactobacillus strains were tested for the production of hydrogen peroxide and antimicrobial compounds along with probiotic properties.ResultsOf the 10 isolated Lactobacillus strains, strain 1, 3 and 6 are high hydrogen peroxide producers and the rest were low producers. Results of pH and amines tests indicated that pH increased with fishy odour in the vaginal fluids of cervicovaginal infection patients when compared with vaginal fluids of healthy persons. The isolates were found to be facultative anaerobic, Gram-positive, non-spore-forming, non-capsule forming and catalase-negative bacilli. The results of antimicrobial activity of compounds indicated that 280 and 140 μg/mL was the minimum concentration to inhibit the growth of both pathogens and test organisms respectively.ConclusionsThe results demonstrated that Lactobacillus producing antimicrobial compounds inhibits the growth of cervical pathogens, revealing that the hypothesis of preventing vaginal infection by administering probiotic organisms has a great appeal to patients, which colonize the vagina to help, restore and maintain healthy vagina.     

Effect of broad-spectrum cephalosporins on the microbial flora of recipients

The flora in the throat and the stools of 10 patients receiving chemotherapy for malignant diseases in a laminar air-flow room was studied during the prophylactic administration of ceftazidime. Ten percent of aerobic gram-negative bacilli, 41% of aerobic gram-positive organisms, 59% of anaerobes, and 70% of fungi persisted in stool specimens during ceftazidime administration. This drug had a less pronounced effect on the throat flora; 66% of organisms persisted during antibiotic administration. The throat and fecal flora of another eight patients were studied during the prophylactic administration of ceftriaxone. This antibiotic had a profound effect on the fecal flora; none of the gram-negative bacilli, only 24% of aerobic gram-positive organisms, and only 10% of anaerobes persisted during ceftriaxone administration. Like ceftazidime, ceftriaxone had a less marked effect on the throat flora; 59% of organisms persisted during antibiotic administration. The results show that new, expanded-spectrum cephalosporins can have a major suppressive effect on patients' endogenous microbial flora.     

Ecological studies on intestinal microbial flora of Kenyan children with diarrhoea

The intestinal microflora was analysed together with short-chain fatty acids (SCFA) and bile acids in faeces from nine children with acute diarrhoeal disease in Lari, Kenya. Enteric pathogens such as enteroinvasive E. coli, enteropathogenic E. coli, Yersinia enterocolitica, rotavirus, Giardia lamblia and Entamoeba histolytica were isolated either singly or in combination from diarrhoeal faecal specimens. The most striking finding in these patients was a marked reduction of anaerobes. Analysis of the SCFA revealed a significantly higher quantity of the volatile fatty acids (VFA) such as acetic, propionic, and butyric acid in recovery period faeces in comparison to diarrhoeal faeces, although no significant difference was seen in the quantity of non-volatile fatty acids. On analysing bile acids in faeces, conjugated primary bile acids were detected from all cases in diarrhoea whereas the free form of secondary bile acids was seen only in recovery. The pH of recovery faecal specimens was significantly lower than that in diarrhoeal faecal specimens. There was a parallel between the decrease in number of anaerobes and fluctuation in the amount of SCFA, showing that the drastic reduction of VFA accompanying decrease of anaerobes during the diarrhoeal state, and the rise in pH thought to arise from these facts, result in an increase of water content.     

Enteric microbial flora, bacterial overgrowth, and short-bowel syndrome.

Small intestinal bacterial overgrowth (SIBO) occurs commonly in short-bowel syndrome (SBS) and, in some instances, may result in significant problems. SIBO is characterized by a variety of signs and symptoms resulting from nutrient malabsorption caused by an increased number and/or type of bacteria in the small intestine. The anatomic and physiologic changes that occur in SBS together with medications commonly used in these patients facilitate the development of SIBO. Because many aspects related to SIBO in the SBS population remain poorly understood, it was our aim to review the current understanding of the gut flora and issues related to SIBO occurring in SBS.     

Bacterial interference between Clostridium difficile and normal fecal flora

Clostridium difficile has been shown to be the cause of virtually all cases of pseudomembranous colitis related to the administration of antimicrobial agents. It is possible that some antimicrobial agents alter the normal bacterial flora of the gastrointestinal tract so as to permit colonization and/or proliferation by C. difficile. The inhibitory activity of representative fecal bacteria from 23 anaerobic and aerobic genera against C. difficile was examined using two in vitro procedures. Strains of bacteria in six of the genera inhibited the multiplication of C. difficile, with Lactobacillus organisms and group D enterococci displaying the most antagonistic activity. C. difficile was examined for its ability to inhibit the multiplication of several fecal strains of anaerobic and aerobic bacteria. All eight strains of C. difficile tested inhibited the growth of particular strains of bacteria in the genera Bacteroides, Peptococcus, and Peptostreptococcus.     

Effects of the spermicidal agent nonoxynol-9 on vaginal microbial flora.

The use of nonoxynol-9--containing vaginal contraceptive preparations increases vaginal (and urethral) colonization by Escherichia coli. Nonoxynol-9 is toxic to various microorganisms, including Lactobacillus acidophilus, but has little or no direct effect on E. coli. L. acidophilus, which is present in the vaginas of most normal women, generates H2O2 which, when combined with peroxidase and a halide, was toxic to E. coli. This toxicity was inhibited by nonoxynol-9 due to the selective destruction of the lactobacilli. In contrast, at higher concentrations, nonoxynol-9 was toxic to E. coli when combined with peroxidase and a halide. This toxicity was shared with certain other nonionic detergents and was due to the formation of peroxides in the preparations on prolonged exposure to oxygen. E. coli colonization may, in part, reflect the balance between these opposing effects of nonoxynol-9 on the vaginal antimicrobial system. Further, damage to normal tissues by peroxides in nonoxynol-9 preparations needs to be considered.