The Role of Glutamine in the Complex Interaction between Gut Microbiota and Health: A Narrative Review

The scientific literature has demonstrated that glutamine is one of the main beneficial amino acids. It plays an important role in gut microbiota and immunity. This paper provides a critical overview of experimental studies (in vitro, in vivo, and clinical) investigating the efficacy of glutamine and its effect on gut microbiota. As a result of this review, we have summarized that glutamine could affect gut microbiota via different mechanisms including the reduction in the ratio of Firmicutes to Bacteroidetes, with the activation of NF-κB and PI3K-Akt pathways, reducing the intestinal colonization (Eimeria lesions) and bacterial overgrowth or bacterial translocation, increasing the production of secretory immunoglobulin A (SIgA) and immunoglobulin A+ (IgA+) cells in the intestinal lumen, and decreasing asparagine levels. The potential applications of glutamine on gut microbiota include, but are not limited to, the management of obesity, bacterial translocation and community, cytokines profiles, and the management of side effects during post-chemotherapy and constipation periods. Further studies and reviews are needed regarding the effects of glutamine supplementation on other conditions in humans.

Ageing and infection

Average life expectancy throughout developed countries has rapidly increased during the latter half of the 20th century and geriatric infectious diseases have become an increasingly important issue. Infections in the elderly are not only more frequent and more severe, but they also have distinct features with respect to clinical presentation, laboratory results, microbial epidemiology, treatment, and infection control. Reasons for increased susceptibility include epidemiological elements, immunosenescence, and malnutrition, as well as a large number of age-associated physiological and anatomical alterations. Moreover, ageing may be the cause of infection but infection can also be the cause of ageing. Mechanisms may include enhanced inflammation, pathogen-dependent tissue destruction, or accelerated cellular ageing through increased turnover. In most instances, treatment of infection leads to a satisfactory outcome in the elderly. However, in palliative care situations and in patients with terminal dementia, the decision whether or not to treat an infectious disease is becoming a difficult ethical issue.

Enteric bacterial flora and bacterial overgrowth syndrome

Under certain conditions, colonic bacterial flora can colonize the upper small bowel in concentrations sufficient to cause mucosal damage and malabsorption of nutrients, vitamin B12, and fat-soluble vitamins. This situation, known as small bowel bacterial overgrowth syndrome (SBBOS) may be an under-appreciated cause of malnutrition in elderly people. The diagnosis of SBBOS should be considered when patients with known or suspected predisposing conditions have symptoms or findings compatible with this syndrome. However, proof of small bowel bacterial overgrowth requires specialized testing that is not readily available. Moreover, disagreement persists as to how best to test definitively for this disease. Therefore, on a practical level and despite the potential drawbacks of such a decision, SBBOS is usually diagnosed when a compatible syndrome responds to an empirical trial of appropriate oral antibiotics. Improvements on this approach to SBBOS will be built on more widespread access to sensitive, specific, and less cumbersome testing than is currently available.

Cryptosporidiosis stimulates an inflammatory intestinal response in malnourished Haitian children

The mechanisms by which Cryptosporidium parvum cause persistent diarrhea and increased morbidity and mortality are poorly understood. Three groups of Haitian children <18 months old were studied: case patients, children with diarrhea not due to Cryptosporidium, and healthy control subjects. Compared with both control groups, children with acute cryptosporidiosis were more malnourished (including measures of stunting [P=.03] and general malnutrition [P=.01]), vitamin A deficient (P=.04), and less often breast-fed (P=.04). Markers of a proinflammatory immune response, interleukin (IL)-8 and tumor necrosis factor-alpha receptor I, were significantly elevated in the case population (P=.02 and P<.01, respectively), as was fecal lactoferrin (P=.01) and the T helper (Th)-2 cytokine IL-13 (P=.03). The counterregulatory cytokine IL-10 was exclusively elevated in the case population (P<.01). A Th1 cytokine response to infection was not detected. This triple cohort study demonstrates that malnourished children with acute cryptosporidiosis mount inflammatory, Th-2, and counterregulatory intestinal immune responses.

Micronutrient malnutrition, infection, and immunity: an overview

Micronutrient deficiencies and infectious diseases often coexist and exhibit complex interactions leading to the vicious cycle of malnutrition and infections among underprivileged populations of the developing countries, particularly in preschool children. Several micronutrients such as vitamin A, beta-carotene, folic acid, vitamin B12 vitamin C, riboflavin, iron, zinc, and selenium, have immunomodulating functions and thus influence the susceptibility of a host to infectious diseases and the course and outcome of such diseases. Certain of these micronutrients also possess antioxidant functions that not only regulate immune homeostasis of the host, but also alter the genome of the microbes, particularly in viruses, resulting in grave consequences like resurgence of old infectious diseases or the emergence of new infections. These micronutrient infection and immune function interactions and their clinical and public health relevance in developing countries are briefly reviewed in this article.

Prevalence of yeast among children in Nigeria and the United States

Fungal infections have gained considerable importance over the last decade as a result of significant increase in the incidence of opportunistic and systemic candidosis. Although Candida albicans is the predominant causative agent of candidosis, particularly oral disease, recently an epidemiological trend has been observed where other less pathogenic species of Candida, including the newly characterized species Candida dubliniensis, are emerging as significant opportunistic pathogens. The present study aimed to screen for the presence of C. dubliniensis and to compare the recovery of yeast species from 30 seemingly healthy and 30 HIV-positive children in the United States, as well as from 64 malnourished Nigerian children. Oral samples were cultured for fungal growth, and all germ tube and chlamydospore positive isolates were tested for ability to grow at 45 degrees C to differentiate between C. albicans and C. dubliniensis. All isolates were speciated based on colony color production on CHROMagar medium and sugar assimilation profiles. Among the 30 HIV-positive children, 15 (50%) were positive for fungus; 12 were positive for C. albicans, with one of the latter also positive for Candida glabrata, and three were found to harbor C. dubliniensis. Among the 30 non-HIV-positive children, five C. albicans and four C. dubliniensis isolates were recovered. No C. dubliniensis isolates were recovered from the Nigerian group. However, eight other different yeast species were recovered from 31 (48.4%) of the 64 Nigerian children sampled, with six of them growing a combination of species. In comparing the data from the Nigerian and United States children, the frequency of yeasts in the malnourished Nigerian group was considerably higher. The most striking difference between the two groups was in the variety of the usually less encountered and less pathogenic yeast species recovered from the Nigerian population. The findings support previously reported observations that there may be intrinsic differences between different populations sampled and that malnutrition might favor the presence of yeast species other than C. albicans.

Urinary tract infection and antibiotic susceptibility in malnourished children

In this study, 31 (30%) cases of urinary tract infection (UTI) of 103 patients with malnutrition, who were admitted to our hospital, were investigated prospectively. Our purpose was to determine the frequency of UTI, species of bacteria caused to infection and their antibiotic susceptibility in infants with malnutrition. The mean age of the patients with UTI was 11.5+/-7.6 months (ranging 50 days-30 months). The main symptoms were fever, vomiting, diarrhea, cough, and seizures. The mean body weight was 5.8+/-1.9 kg (2-10 kg), and height was 67.5+/-7.8 cm (53-85 cm). Seven of them had mild, 11 had moderate, and 13 had severe malnutrition. The most common isolated microorganism from urine cultures was Escherichia coli (54.8%). Most strains of Escherichia coli were resistant to co-trimoxazole (82.3%), ceftriaxone (17.6%), cefotaxime (17.6%), and ciprofloxacine (17.6%), but none of them were resistant to gentamicin. In conclusion, we would like to emphasize that UTI predominantly by gram negative microorganisms are frequent in the infants with malnutrition, and these microorganisms are mostly resistant to co-trimoxazole which is used commonly in practical medicine and prophylaxis.

The appropriateness of the current antibiotic empiric therapy based on the bacteria isolated from severely malnourished Jamaican children

We performed a retrospective audit of antimicrobial sensitivities of bacteria isolated from children admitted with a diagnosis of malnutrition to the Tropical Metabolism Research Unit (TMRU), University of the West Indies, between January 1995 and December 1999. There were 150 admissions for severe malnutrition to the TMRU during this period, which was approximately 50% fewer than in a previous TMRU study done ten years ago, between 1984 and 1989. In the present study, bacteraemia was documented in 10% of 150 severely malnourished children between 1 and 31 months of age. The most common organisms isolated were coagulase-negative Staphylococci, which represented 40% of the total isolates. The micro-organisms grown were most likely to be sensitive to amoxycillin/clavulanic acid. The current TMRU treatment protocol for severe malnutrition recommends use of crystalline penicillin plus gentamicin as empirical antibiotic therapy. This study has provided valuable information suggesting that the current empiric antibiotic therapy may be inappropriate.

Isolation of fusobacteria from the oral cavities of malnourished Nigerian children living in agricultural and herding villages

A previous study demonstrated the presence and possible involvement of Fusobacterium necrophorum in the pathogenesis of noma lesions of children living in agricultural and herding villages in northwestern Nigeria. In order to determine if F. necrophorum was part of the oral flora of malnourished children with no noma lesions, a study of the fusobacteria present in the oral cavities of 30 children, 2-6 years of age in Sokoto State, was undertaken. Swabs taken of the oral cavity were cultured on selective fusobacteria medium using conventional anaerobic microbiological techniques. F. nucleatum was recovered from each child and F. necrophorum was isolated from the oral cavity of only one child. The presence of F. nucleatum and the lack of F. necrophorum, except in one case, suggests that the latter is not normal flora in the children at risk for noma. F. necrophorum, a putative trigger organism for noma may gain a foothold only when certain staging conditions (i.e., lowered host resistance and/or oral lesion) are present.

The gut at war: the consequences of enteropathogenic Escherichia coli infection as a factor of diarrhea and malnutrition

Diarrheal disease is still the most prevalent and important public health problem in developing countries, despite advances in knowledge, understanding, and management that have occurred over recent years. Diarrhea is the leading cause of death in children under 5 years of age. The impact of diarrheal diseases is more severe in the earliest periods of life, when taking into account both the numbers of episodes per year and hospital admission rates. This narrative review focuses on one of the major driving forces that attack the host, namely the enteropathogenic Escherichia coli (EPEC) and the consequences that generate malnutrition in an early phase of life. EPEC serotypes form dense microcolonies on the surface of tissue-culture cells in a pattern known as localized adherence (LA). When EPEC strains adhere to epithelial cells in vitro or in vivo they cause characteristic changes known as Attaching and Effacement (A/E) lesions. Surface abnormalities of the small intestinal mucosa shown by scanning electron microscopy in infants with persistent diarrhea, although non-specific, are intense enough to justify the severity of the clinical aspects displayed in a very young phase in life. Decrease in number and height of microvilli, blunting of borders of enterocytes, loss of the glycocalyx, shortening of villi and presence of a mucus pseudomembrane coating the mucosal surface were the abnormalities observed in the majority of patients. These ultrastructural derangements may be due to an association of the enteric enteropathogenic agent that triggers the diarrheic process and the onset of food intolerance responsible for perpetuation of diarrhea. An aggressive therapeutic approach based on appropriate nutritional support, especially the utilization of human milk and/or lactose-free protein hydrolyzate-based formulas and the adequate correction of the fecal losses, is required to allow complete recovery from the damage caused by this devastating enteropathogenic agent.

Microbiological understandings and mysteries of noma (cancrum oris)

The microbiologic history of noma was reviewed. Studies have associated the disease process with large numbers of fusiform bacilli and spirochetal organisms. In order to study the microbiology of the staging and infection periods of noma 62 Nigerian children, aged 3-14 years, 22 children had acute necrotizing ulcerative gingivitis (ANUG) and were also malnourished, 20 exhibited no acute necrotizing ulcerative gingivitis but were malnourished and 20 were free of acute necrotizing ulcerative gingivitis and in good nutritional state) were evaluated for the presence of viruses and oral microorganisms. The ANUG cases in the malnourished children had a higher incidence of Herpesviridae, the main virus being detected was cytomegalovirus. There were more anaerobic microorganisms recovered, with Prevotella intermedia as the predominant isolate, in the malnourished children as compared to the healthy children. A study of the predominant microflora in active sites of noma lesions was carried out in eight noma patients, 3-15 years of age, in Sokoto State, northwestern Nigeria. Fusobacterium necrophorum was recovered from 87.5% of the noma lesions. Oral microorganisms isolated included Prevotella intermedia, alpha-hemolytic streptococci and Actinomyces spp. which were isolated from 75.0, 50.0 and 37.5% of the patients, respectively. Peptostreptococcus micros, Veillonella parvula, Staphylococcus aureus and Pseudomonas spp. were each recovered from one lesion. All strains were observed to be sensitive to all of the antibiotics tested with the exception of one strain of P. intermedia which showed resistance to penicillin. The pathogenic mechanisms of F. necrophorum as a trigger organism were discussed. The isolation from human noma lesions of F. necrophorum, a pathogen primarily associated with animal diseases, may have important etiologic and animal transmission implications.

Bacterial overgrowth, intestinal transit, and nutrition after total gastrectomy. Comparison of a jejunal pouch with Roux-en-Y reconstruction in a prospective random study

BACKGROUND

Jejunal pouches after total gastrectomy have been introduced to diminish postgastrectomy symptoms and improve nutrition. However, the effect of a pouch on the intestinal bacteriology and transit is controversial.

METHODS

Bacterial overgrowth was measured with the glucose breath test and the mouth-to-caecum transit time (MCT) by means of the lactulose breath test after total gastrectomy and Roux-en-Y reconstruction in 24 patients with a pouch (Pouch group) and in 22 patients without a pouch (Roux-en-Y group). Postoperative symptoms were evaluated with a standard questionnaire, and nutrition was measured by blood chemistry and weight loss.

RESULTS

MCTT was 110 +/- 44 min in the Roux-en-Y group and 117 +/- 44 min in the Pouch group (NS). Eighty-six per cent of the patients in the Roux-en-Y group and 91% of the patients in the Pouch group had bacterial overgrowth (NS). Transit time was shorter in patients with severe dumping than patients without dumping (60 +/- 28 min versus 115 +/- 41 min; P = 0.04). Maximal hydrogen concentration in the glucose breath test correlated negatively with serum albumin and iron concentrations and with postoperative weight loss, and positively with serum alkaline phosphatase activity.

CONCLUSIONS

Bacterial overgrowth is common in the upper intestine after total gastrectomy. Pouch reconstruction does not delay the transit of liquids. Bacterial overgrowth may be one of the main aetiologic factors in postgastrectomy malnutrition.

Prevalence of Helicobacter pylori infection in Nicaraguan children with persistent diarrhea, diagnosed by the 13C-urea breath test

BACKGROUND

The impairment of gastric acid barrier caused by Helicobacter pylori (H. pylori) at the onset of infection may predispose to small bowel bacterial overgrowth, which could contribute to persistent diarrhea.

METHODS

Using the 13C-urea breath test, we determined the prevalence of H. pylori infection in 123 Nicaraguan children from Tipitapa, aged 1 to 65 months, from a low socioeconomic background.

RESULTS

The overall prevalence of H. pylori infection was 77.2% (95/123). The prevalence varied with age and was significantly (p < 0.001) higher in infants < or = 12 months than in children aged 13-65 months, 91% (57/63) as against 63% (38/60). H. pylori infection was present in 44 of 59 (75%) children suffering from persistent diarrhea compared with 51 of 64 (80%) age-matched asymptomatic controls. In the diarrheal group, 20 of 59 (34%) children presented with malnutrition, and 16 (80%) of them showed H. pylori infection. In the control group, 20 of 64 (31%) were malnourished, and 14 (70%) of them showed H. pylori infection.

CONCLUSIONS

In Nicaragua, H. pylori is acquired in early infancy. The high prevalence among children in the first 12 months of life and the lower infection rate between 1 and 5 years of age suggest a loss or clearance of infection, also an occasional finding in adults. H. pylori infection appears to be not a risk factor for persistent diarrhea or malnutrition in Nicaraguan children.

Influence of malnutrition on the prevalence of bacterial translocation and spontaneous bacterial peritonitis in experimental cirrhosis in rats

Bacterial translocation (BT) has been involved in the pathogenesis of spontaneous bacterial peritonitis (SBP) in experimental cirrhosis. Because malnutrition is a common feature in cirrhosis, the aim of this study was to evaluate the effect of nutrition on BT and SBP. We induced cirrhosis in 44 Sprague-Dawley rats by administration of oral CCl4, and, afterward, 26 animals were maintained with dietary restriction. Cultures of mesenteric lymph nodes (MLN), peripheral and portal blood, liver, and spleen were performed. SBP occurred in 48% of the rats with ascites, this being more frequent in the malnourished animals (80%) than in control rats (29%). BT appeared in all the rats with SBP (100%) but only in 57% without it. In the malnourished animals, the BT rate was 95%, while it was 30% in the control group. These results suggest that malnutrition increases the BT rate and the risk of developing SBP in experimental cirrhosis, and that BT is frequent in cirrhosis and may play a role in the development of SBP.

[Helicobacter pylori infection in developing countries]

Helicobacter pylori infection is probably the most common bacterial infection in the world. The pathogenicity of this bacteria has been recognized since 1989 in the developed world where prevalence is 20 to 40%. Its role in gastric and duodenal disease is certain and its low recurrence rate justifies eradication. In the developing world prevalence of Helicobacter pylori infection is over 80% with contamination being maximal in children. Transmission is oro-oral and even feco-oral. Crowded living conditions is the determinant factor. Helicobacter pylori infection exhibits special features in developing world. The prevalence of gastroduodenal disease varies according to geographic area independently of the prevalence of Helicobacter pylori infection and stomach cancer is uncommon. In newborns Helicobacter pylori infection seems to be the primary event for chronic malnutrition and diarrhea syndrome with failure to thrive. In practice detection of Helicobacter pylori is difficult in the developing world and presumptive treatment is always followed by recurrence. In the future active or passive immunization will be the solution.

Effect of early nutritional deprivation and diet on translocation of bacteria from the gastrointestinal tract in the newborn rat

The gastrointestinal (GI) barrier function is immature in the preterm neonate and might thus facilitate translocation of enteric bacteria and gut-derived septicemia. Circumstantial evidence suggests that bacterial uptake from the intestine may be further enhanced by an alteration of the host nutritional status. To test this hypothesis, neonatal rats were fed normal or restricted amounts of either breast milk or of a rat milk-simulated formula for 3-5 d. At the end of the study, various sections of the GI tract, mesenteric lymph nodes, liver, spleen, and blood were analyzed for bacteria using standard microbiologic procedures. Normal breast feeding was associated with bacterial translocation to mesenteric lymph nodes and in some cases to liver or spleen in 27% of rats, whereas all bacterial cultures were negative in a control group killed immediately after birth. Restricted breast feeding did not increase translocation compared with normal breast feeding. By contrast, feeding normal or restricted amounts of formula increased the numbers of gut bacteria by 2-3 logs, altered the morphology of the small intestinal mucosa, and resulted in ample bacterial translocation to the mesenteric lymph nodes and to systemic organs including the blood. Bacterial translocation may normally occur in suckling neonatal rats and is not increased by food restriction. Artificial feeding dramatically enhances translocation of gut bacteria.

Royal Society of Tropical Medicine and Hygiene Meeting at Manson House, London, 16 February 1995. Aspects of Helicobacter pylori infection in the developing and developed world. Helicobacter pylori infection, nutrition and growth of West African infants

Helicobacter pylori is probably the commonest bacterial infection of humankind. In adults, colonization of the stomach is associated with chronic gastritis and duodenal ulcer disease. However, children in the developing world acquire H. pylori soon after birth, and there is evidence that it plays a part, through suppression of the gastric acid barrier, in the pathogenesis of the syndrome of diarrhoea, malnutrition and growth failure. Infants born of mothers who secrete milk with high levels of anti-H. pylori immunoglobulin A (IgA) antibody acquire the infection later than those born of mothers with low specific antibody levels. Enhancement of maternal breast milk anti-H. pylori IgA levels may protect infants from H. pylori infection during the vulnerable weaning period when many are susceptible to enteric infections, leading to recurrent diarrhoea and adverse consequences on nutrition and growth.

Malnutrition in the developing and developed world: is small intestinal bacterial colonization important?

Malnutrition is a major problem on a global basis and will continue if current world population trends persist. Small intestinal bacterial colonization may contribute to malnutrition in populations whose dietary intake is marginal, such as those in developing countries and many elderly in the developed world. This review focuses on the evidence for small intestinal bacterial colonization in these subjects and briefly revises current thinking on the pathogenesis and diagnosis of this condition.

Study of microflora in well-nourished and mal-nourished children in relation to dental caries

Forty-five children in the age group of 2-12 years comprising 20 well-nourished (W.N.), 20 malnourished (M.N.) (both groups having DMFS of > or = 5) and 5 caries free well nourished children (control group) were studied to find out the oral microflora in these groups S. mutans was present in 55%, 20% and 0% in W.N., M.N., and control groups while S. Salivarius was isolated in 45%, 80% and 40% in the three groups respectively. There was no significant difference in the prevalence of Lactobacillus and C. albicans in the three groups. The correlation between means DMFS and the prevalence of S. mutans in W.N. and M.N. groups was highly significant (P < 0.001). Nutritional status including different grades of malnutrition had no significant bearing on the prevalence of micro-organisms isolated. The caries prevalence was higher in the W.N. group (P) while the gingival index was higher in M.N. group.

Bacterial translocation: the influence of dietary variables

Transmucosal passage of bacteria in critically ill patients may lead to a significant incidence of systemic sepsis. This has attracted much clinical interest, as it has been shown that malnutrition in itself, impairs various aspects of barrier function. Bacterial translocation is increased in animal models where nutrients are given by the parenteral route, while enteral feeding reverses this. Translocation is also considerably increased in response to a non-lethal endotoxin challenge, if there is pre-existing protein energy malnutrition. Similar results have been obtained where the insult is caused by the inflammatory agent, zymosan. Dietary fibre reduces the deleterious effects of either agent on translocation, although the type of fibre is important. Bulk forming but non-fermentable fibres are more effective than easily fermentable types (for example, pectin). Glutamine was not effective in preventing elemental diet induced bacterial translocation. Thus, although fermentable fibre and glutamine have positive effects on mucosal mass, they do not affect translocation. Enteral nutrition thus seems to be superior to parenteral nutrition in maintaining the functional barrier of the gut. A clearer understanding of the physiology of these effects may lead to use of specifically modified enteral diets in the critically ill patient.

Efficacy of massive dose oral gentamicin therapy in nonbloody persistent diarrhea with associated malnutrition

Overgrowth of aerobic and anaerobic bacteria in the upper small intestine is a common finding in persistent diarrhea. We hypothesized that a large dose of broad spectrum, nonabsorbable oral antibiotic would hasten recovery from persistent diarrhea by eradicating aerobic bacterial overgrowth. Sixty-eight patients were randomly assigned to treatment with either oral gentamicin (n = 33) or placebo (n = 35) for a period of 6 days. The two groups were comparable in their clinical features, stool weights, duodenal and fecal microflora, during an initial 24 h observation period before randomization. The proportion of patients recovering within 6 days post-treatment was similar in the antibiotic (45.2%) and placebo (50%) groups. The stool weights in the two groups during 24-72, 72-120, and 120-168 h of the study did not differ significantly. The percent mean weight gain (g) at 168 h post-treatment in the antibiotic (1.0 +/- 5.1) and placebo (1.4 +/- 5.3) groups also did not differ significantly (p = 0.8). A similar proportion of antibiotic- (61.3%) and placebo- (60.7%) treated patients had started to gain weight by the last day of the study. We conclude that oral gentamicin was no more effective than placebo in reducing purge rates, in achieving earlier recovery from diarrhea, and in promoting the earlier onset of weight gain in this study.

Candida-associated diarrhea in hospitalized patients

Ten hospitalized patients with severe diarrhea associated with intestinal Candida overgrowth are reported. Candida-associated diarrhea is predominantly of the secretory type, characterized by frequent watery stools, usually without blood, mucus, tenesmus, or abdominal pain. The patients were elderly, malnourished, and critically ill, or suffered from chronic debilitating illness. Their hospital stays were prolonged, and the majority were being treated with multiple antibiotics or chemotherapeutic agents. Diarrhea often led to dehydration, prerenal azotemia, hyperchloremic metabolic acidosis, and electrolyte imbalance. Stool culture most frequently isolated Cand. albicans in association with decreased normal flora. Colonoscopy showed no evidence of colitis. Diagnosis was made based on the absence of diarrhea-producing medications, the continuation of diarrhea despite fasting, the exclusion of other infections, inflammatory conditions and other causes of secretory diarrhea, and a dramatic response to a short course of nystatin.

Bacterial overgrowth

Small bowel bacterial overgrowth is a syndrome manifested by malabsorption, weight loss, and diarrhea. Human intestinal flora is part of a complex ecosystem regulated by host mechanisms, environmental factors, and bacterial interactions. Numerous conditions can tilt this balance to favor bacterial contamination of the gut. Knowledge of intestinal microbial control enables the clinician to better understand the pathophysiology and the clinical features of this disorder. Current strategies in diagnosis and therapy are discussed.

[Giardia lamblia infestation at child day care centers. Nutritional impact in infested children]

Seventy-five children attending a day care center (42 girls and 33 boys, aged from 6 to 65 months) were surveyed for excretion of Giardia lamblia cysts. Cyst excretion was found in 17 (23%) of the children, 9 of whom were still positive 6 months later. Weight, height and arm skinfold thickness of each subject were obtained and compared to normal values in the Québec population; a questionnaire concerning gastrointestinal symptoms was filled out for each child. No difference in weight, height, skinfold thickness or in frequency of gastrointestinal symptoms was found when comparing cyst excretors to children with a negative stool examination. This study suggests that G. lamblia infestation has little or no nutritional impact. This should be confirmed by a larger study.

Upper small intestinal microflora in diarrhea and malnutrition in Nigerian children

The upper small intestinal microflora was determined quantitatively and qualitatively in a group of well-nourished diarrhea-free Nigerian children and compared with those of well-nourished children with acute diarrhea and malnourished children with or without diarrhea. Intestinal aspirate was collected by intubation after a 6-h fast. Well-nourished children without diarrhea had flora consisting predominantly of gram-positive cocci. Total bacterial counts were less than 10(5) organisms/ml; 18.2% of aspirates were sterile. In contrast, malnourished children with or withour diarrhea had a wider microbial spectrum including Enterobacteriaceae, Bacteroides, and Candida. Total bacterial counts were between 10(3) and 10(9) organisms/ml; none were sterile. In both well-nourished and malnourished groups, no significant quantitative bacteriologic differences were found between patients who had diarrhea and those who did not. Candida and Pseudomonas were found more frequently in malnourished patients with diarrhea. In such diarrheal patients, Pseudomonas, Klebsiella, and enteropathogenic Escherichia coli grew as pure isolates in intestinal aspirates and could be detected concomitantly in their stools. These results establish the upper small intestinal flora of well-nourished diarrhea-free Nigerian children, confirm bacterial overgrowth as a feature of malnourished children with or without diarrhea, and suggest that Candida, Pseudomonas, and Klebsiella may account partly for the diarrhea seen in malnourished children.

Frequency and density of yeasts in the mouths of malnourished children

The prevalence and density of yeasts and Candida albicans on the buccal mucosa and dorsum of the tongue have been assessed in 106 children in Crossroads squatter camp, South Africa. They were divided into a malnourished and a control group on the basis of an age/weight chart. No differences were found in yeast prevalence and density in the two groups. However, malnourished children more frequently had a mucosal density of yeasts, and particularly C. albicans, exceeding the upper limit normally found in health, in the absence of clinical infection. Some evidence was found to suggest that yeast density might be influenced by sex as well as nutritional status.

[Composition of the intestinal microflora in children with hypotrophy]

The intestinal microflora was investigated in 120 children aged 1 month to 2 years with different forms of hypotrophy. The majority of the children demonstrated an impairment of intestinal biocenosis manifesting by dysbacteriosis of different gravity. The relationship was discovered between the depth of the dysbiotic abnormalities and the underlying etiological factor that promoted the development of the chronic nutrition distress, hypotrophy gravity, the type of feeding, and treatment. The treatment of hypotrophy with bacterial drug inclusion made the children's intestinal microflora return to normal or appreciably improved it. The dysbiotic abnormalities in children with hypotrophy should be regarded as the result of the long-term use of antibacterial therapy (not justified in all the cases) in this patients' group, of inadequate feeding, and a considerable decrease of the body resistance.

Patterns and routes of tracheobronchial colonization in mechanically ventilated patients. The role of nutritional status in colonization of the lower airway by Pseudomonas species

Tracheobronchial colonization by Gram-negative bacteria is common in mechanically ventilated patients. Pseudomonas sp are commonly isolated from the lower airways. We hypothesized that Pseudomonas sp would preferentially colonize the lower airway and would be more common in patients with poor nutritional status. We serially collected 75 pairs of upper and lower respiratory tract cultures from 14 patients treated with mechanical ventilation for at least one week, examined patterns of airway colonization and routes of bacterial entry for Pseudomonas sp and other enteric Gram-negative bacteria (EGNB), and related these findings to host-associated factors, including nutritional status. Pseudomonas sp were the most common species isolates taken from the lower airway, found in nine of 14 patients and in 41.3 percent of all cultures. In contrast to other EGNB, Pseudomonas sp were found significantly (p less than or equal to 0.05) more often in the tracheobronchial tree (31 of 75 cultures) than in the oropharynx (18 of 75 cultures). Primary colonization of the lower airway by Pseudomonas sp was found in four patients, while other EGNB never followed this pattern when subjects were studied with cultures taken every third day. A host-related factor related to lower airway colonization by Pseudomonas species was poor nutritional status, assessed by a multifactorial index (p less than or equal to 0.01). We conclude that in mechanically ventilated patients, Pseudomonas sp colonize the lower airway in a different pattern and by a different route from those of other EGNB. The findings that Pseudomonas sp preferentially colonize the tracheobronchial tree may be important for the design of strategies to prevent airway colonization. The recognition that poor nutritional status, a potentially modifiable host-related factor, favors lower airway growth of Pseudomonas sp suggests one direction for future infection-control efforts.

[Effectiveness of using Maliutka and Malysh adapted propionic-acidophilus mixtures in the combined treatment of congenital hypotrophy]

The physical and psychomotor development, immune responsiveness, and intestinal microflora were studied in 82 infants with congenital hypotrophy depending on the nutrition pattern. It was shown that children who received the propionic-acidophilic mixtures Malyutka and Malush manifested the highest daily weight gain, the most rapid disappearance on the manifestations of food allergy, an increase in immune responsiveness. A decrease in the cultivation rate of Proteus vulgaris and pathogenic staphylococcus, as well as an increase in the cultivation of bifidobacteria. The data obtained permit recommending the use of the propionic-acidophilic mixtures Malyutka and Malysh in combined treatment of children with congenital hypotrophy.

Nutritional status and bacterial binding in the lower respiratory tract in patients with chronic tracheostomy

Patients with chronic tracheostomy often develop tracheobronchial colonization with enteric gram-negative bacilli, especially Pseudomonas aeruginosa, but pathogenic mechanisms are largely unknown. To examine this problem, we measured in-vitro bacterial adherence to airway epithelial cells from the tracheal surfaces of 15 patients with chronic tracheostomy and 18 healthy, noncolonized controls without tracheostomy. Patients with tracheostomy had more tracheal cell adherence (7.3 +/- 0.4 [SE] bacteria/cell) than controls (4.8 +/- 0.7 bacteria/cell; p = 0.008), but patients colonized by Pseudomonas species had even more binding (9.0 +/- 0.06 bacteria/cell) than those without this finding (5.8 +/- 0.8 bacteria/cell; p = 0.008). Differences between patients in lower airway cell binding of bacteria were largely related to a multifactorial assessment of patient nutritional status, the prognostic nutritional index (r = 0.67, p = 0.005). Thus, nutritional status may account in part for the common problem of tracheobronchial colonization with gram-negative bacteria in patients with chronic tracheostomy.

Increased adhesion of Escherichia coli to mucosal cells from infants with protracted diarrhoea: a possible factor in the pathogenesis of bacterial overgrowth and diarrhoea

Mucosal adhesion of bacteria has been studied in eight infants with protracted diarrhoea and malnutrition, using a buccal epithelial cell technique. A known non-adhesive strain of Escherichia coli (O1:K1:H7) adhered to a significantly greater (p less than 0.001) proportion of buccal epithelial cells from patients with protracted diarrhoea, compared with children with acute diarrhoea, healthy infants, and healthy adults. Also, Enterobacteria isolated from the jejunum or stools of patients with protracted diarrhoea adhered to far greater numbers of their own buccal epithelial cells compared with healthy adults. These results suggest that bacterial adhesion may play an important role in the pathogenesis of protracted diarrhoea.

A comparison of the prevalence of campylobacter, Shigellae and Salmonellae in faeces of malnourished and well nourished children in The Gambia and Northern Nigeria

The proportion of children in whom bacterial pathogens were isolated in faeces was compared in 59 malnourished and 59 age-matched well nourished children in Fajara, The Gambia, with 38 malnourished and 38 age-matched well nourished children in Malumfashi, Northern Nigeria. Campylobacters were identified more frequently in malnourished (10.2%) and well nourished (6.8%) children in The Gambia than in malnourished (2.6%) and well nourished (2.6%) children in Nigeria. Salmonellae were more frequently isolated in the malnourished Nigerian children (28.9%) than in the malnourished Gambian children (3.4%) and were present in similar proportions (5.1% and 5.3%) in well nourished children in both communities. Shigellae were isolated in a few individuals in each group. The differences in the epidemiology of these enteropathogens are discussed with respect to the differences in ecology between these two sub-Saharan, savanna communities.

[Duodenal microflora in malnourished infants with acute diarrhea, carbohydrate intolerance and cow's milk protein intolerance]

Duodenal microflora was studied in three groups of malnourished infants: I) 10 cases with acute diarrhea; II) six carbohydrate intolerant infants; III) eight cases with cow's milk protein intolerance. In all of them it was observed linear increases of overgrowing flora, with a greater incidence of Gram negative microorganisms. The greatest number of bacterial counts, with mixed flora was found in group III. In group II, "Escherichia coli" was present in all the cultured aspirates, suggesting that it was not a random fact, and could be the agent responsible of diarrhea.

Nutritional status, globulin titers, and parasitic infections of two populations of Tanzanian school children

Two schools in rural Tanzania were surveyed regarding the pupils' nutrition (weight and height), serum immunoglobulins (IgA, IgG, IgM, and IgE), autoantibodies, malaria antibodies, hepatitis B antigenemia, and fecal and urinary parasites. The survey attempted to quantify the relative importance of undernutrition and parasitic infestation in determining the serological abnormalities found. Of all the children surveyed 69% were undernourished (less than 80% of expected weight for age); 63% had fecal parasites and 38% had urinary schistosomiasis. Serum IgG and IgM concentrations were raised and the serum IgE concentration was strikingly raised (mean 4990IU/ml). Elevated serum IgE was associated with ascariasis. Autoantibodies were common but no autoimmune disease was detected. Notably there was a 35% prevalence of reticulin antibody. This reticulin antibody positivity correlated with increased malaria antibody concentrations. Reduced malaria antibody concentration was significantly associated with hepatitis B antigenemia. The study illustrates that parasites, notably malaria, are important determinants of the serum antibodies of children in the tropics and suggests that mild undernutrition has little effect.

Effects of intestinal micro-organisms on fluid and electrolyte transport in the jejunum of the rat

Culture filtrates of micro-organisms isolated from the upper intestinal secretions of malnourished children and grown in pure culture were shown to impair the intestinal absorption of water and electrolytes in live rats. Decreased net movement out of the intestinal lumen, or actual secretion of water, sodium or potassium into the intestinal lumen, was found with culture filtrates of single isolates of Staphylococcus epidermidis, Escherichia coli 055, Escherichia coli B7A, Shigella sonnei, Klebsiella pneumoniae, Candida albicans and Candida tropicalis. These organisms have been found to contaminate upper intestinal secretions in malnourished children and it is suggested that the effects observed in these experiments might be relevant to the production of the diarrhoea that is a dominant clinical feature of childhood malnutrition.

Bacterial overgrowth syndrome without "blind loop": A cause for malnutrition in the elderly

Probable bacterial contamination of the small bowel without an anatomical sump occurred in 5 elderly patients (age 68--94). They presented with severe general deterioration in health rather than with obvious features of malabsorption. This syndrome has not been clearly described before. Bacterial deconjugation of bile salts was indentified by the 14C-glycocholic-acid breath test. Investigations for other causes of malabsorption, including small-bowel biopsy and pancreatic scan, revealed no abnormality. After prolonged ill-health despite an adequate diet in hospital, all 5 subjects made a striking recovery after treatment with antibiotics. This condition may be quite common, particularly in malnourished elderly people.

Stool bacterial aerobic overgrowth in the small intestine of children with acute diarrhoea

The aerobic flora of 2 groups of children (normal and with malnutrition) with acute diarrhoea was studied, by intubation of the upper and middle small intestine and by stool culture. All the 27 children studied presented bacterial concentrations of 10(5) germs/ml at one or both levels studied. In 9 cases enteropathogen bacteria e were isolated from stools, and in 6 of these they were also found in the small intestine. The results show the elevated incidence of overgrowth of the small intestinal aerobic flora in children with acute diarrhoea. This fact is mentioned as another etiological factor to be taken into consideration in this pathology.

Effect of microorganisms isolated from the upper gut of malnourished children on intestinal sugar absorption in vivo

The effect of microorganisms isolated from the upper gastrointestinal tract of malnourished children on intestinal sugar absorption was studied in rats in vivo. Pure cultures of organisms were grown overnight in a nutrient broth and the resultant supernatant fluid which contained microorganisms in similar numbers to those found in the patients was used as the basic solution for jejunal perfusions which were done in anesthetized adult Wistar rats. The substrate used was arbutin (p-hydroxphenyl-beta-glucoside), a recognized marker of intestinal active sugar transport. Of the gram-positive cocci studied, only the saprophyte, Staphylococcus saprophyticus, did not adversely affect the intestinal absorption of arbutin. The only gram-positive rod studied, a lactobacillus, also significantly inhibited arbutin absorption. Of the Enterobacteriaciae studied, Salmonella paratyphi B, a Shigella and Proteus sp. did not affect arbutin absorption. All the species of Escherichia coli studied, including a nonpathogenic variety, inhibited absorption. Klebsiella sp. and Pseudomonas sp. were also effective. Of the Candida sp., C. albicans and C. parapsilosis were inhibitory while C. tropicalis was not. These results suggest that microorganisms not generally considered enteropathogenic may adversely affect intestinal function when present in the lumen of the gut in excessive numbers and contribute to the production of diarrhea in children with malnutrition.

Microbial contamination of the gut; another feature of malnutrition

The microbial flora of the stomach and upper small intestine was studied in 21 malnourished Indonesian children with diarrhoea and compared with that found in 21 Australian children of Caucasian extraction with a variety of alimentary disorders. In the Indonesian children there was marked microbial contamination of the upper gastrointestinal tract with a wide variety of microorganisms. In several patients there was significant overgrowth by Candida sp. and in several others large numbers of anaerobic bacteria were isolated. It is suggested that these microbiological abnormalities are related to the pathogenesis of diarrhoea in children with malnutrition.

Jejunal microflora in malnourished Gambian children

Growth of bacteria greater than 10-5 organisms/ml was found in 22 children, of whom 17 gave a histroy of chronic diarrhoea. The other 8 children had either no diarrhoea or where having an acute attack lasting for a few days. In those with chronic diarrhoea, Esch. coli, bacteroides, and enterococci tended to occur more frequently, whereas streptococci occurred more frequently in those with acute diarrhoea. Bacilli, staphylococci, micrococci, klebsiellas, pseudomonads, and candidas often occurred in both groups and in large numbers in those with chronic diarrhoea. This confirms previous reports in other parts of the world that some children with malnutrition have considerable bacterial contamination of the jejunum, and that this may be of aetiological significance as a cause of much of the diarrhoea seen in malnourished children. It is possible too that this may be important in the pathogenesis of malnutrition. The presence of intestinal parasites in these malnourished children is also noted. A double-blind trial in the use of antibiotics in this condition is advocated to determine whether it is possible to break the diarrhoea-malabsorption-malnutrition cycle. At the same time the effect of simply removing the child to a more sanitary environment, together with an estimate of the natural clearance of bacteria from the upper intestine, should be evaluated.