Instruct: Given a question, retrieve documents that answer the question.
Query: C. diff
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a matter of concern worldwide, in particular in the USA. For the analysis of emergence and spread, clear definitions based on epidemiological origin are needed for discrimination between CA-MRSA, healthcare-associated community MRSA, and healthcare-associated MRSA (HA-MRSA). Although its role in pathogenesis is currently under debate, the capability for Panton-Valentine leukocidin formation is associated with the majority of CA-MRSA isolates from North America and from Europe. Most CA-MRSA isolates are attributed to clonal lineages different from HA-MRSA; there are, however, clonal lineages from which both HA-MRSA and CA-MRSA have been reported (e.g. ST1, ST5, ST8, and ST22); CA-MRSA ST8 (USA300), which is most frequent in the USA, has meanwhile been reported from Europe. CA-MRSA ST80 is widely disseminated in Europe; because of its pronounced oxacillin heteroresistance phenotype, cefoxitin-based assays are advisable for reliable detection. So far, CA-MRSA infections seem to be much less frequent in Europe than in the USA, where patients with particular predispositions and low social status are at especial risk.
OBJECTIVES: The prevalence of celiac disease (CD) in the United States is unknown. We sought to estimate CD prevalence nationwide by using a nationally representative sample. METHODS: This study included 7,798 persons aged 6 years or older who participated in the National Health and Nutrition Examination Survey 2009-2010. Serum samples from all participants were tested for immunoglobulin A (IgA) tissue transglutaminase antibodies and, if findings were abnormal, also for IgA endomysial antibodies. Information about prior diagnosis of CD and use of a gluten-free diet (GFD) was obtained by direct interview. CD was defined as having either double-positive serology (serologically diagnosed CD) or a reported diagnosis of CD by a doctor or other health-care professional and being on a GFD (reported clinical diagnosis of CD). RESULTS: CD was found in 35 participants, 29 of whom were unaware of their diagnosis. Median age was 45 years (interquartile range, 23-66 years); 20 were women and 29 were non-Hispanic white. The prevalence of CD in the United States was 0.71% (95% confidence interval (CI), 0.58-0.86%), with 1.01% (95% CI, 0.78-1.31%) among non-Hispanic whites. In all, 55 participants reported following a GFD, which corresponded to a prevalence of 0.63% (95% CI, 0.36-1.07%). CONCLUSIONS: The prevalence of CD in the United States was 0.71% (1 in 141), similar to that found in several European countries. However, most cases were undiagnosed. CD was rare among minority groups but affected 1% of non-Hispanic whites. Most persons who were following a GFD did not have a diagnosis of CD.
Cow's milk allergy (CMA) is nowadays a common problem in Thai children. We reviewed medical records of patients with CMA from the Department of Pediatrics at King Chulalongkom Memorial Hospital of the past 10 years, from 1998 to 2007. The criteria for the diagnosis of CMA included: elimination of cow's milk formula resulting in improvement of symptoms, and: recurrence of symptoms after reintroduction of cow's milk by oral challenge or by accidental ingestion. Of the 382 children with a diagnosis of CMA, 168 were girls and 214 were boys. The average age at the time of diagnosis was 14.8 months (7 days-13 years). The average duration of symptoms before diagnosis was 9.2 months. A family history of atopic diseases was found in 64.2% of the patients. All of the mothers reported an increased consumption of cow's milk during their pregnancy. The most common symptoms were respiratory (43.2%) followed by gastrointestinal (GI) (22.5%) and skin manifestations (20.1%). Less common symptoms included failure to thrive (10.9%), anemia (2.8%), delayed speech due to chronic serous otitis media (0.2%) and anaphylactic shock (0.2%). A prick skin test with cow milk extract was positive in 61.4%. Exclusively breast-fed was found in 13.2% of the patients. Successful treatment included elimination of cow's milk and milk products and substitution with soy formula in 42.5%, partial hydrolysate formula (pHF) in 35.7%, extensive hydrolysate formula (eHF) in 14.2%, and amino acid formula in 1.7%. Continued breast feeding was successful in 5.9% (with maternal restriction of cow's milk and milk products). Our study demonstrates the variety of clinical manifestations of CMA in Thai children especially respiratory symptoms which are usually overlooked.
Diverticular disease of the colon is a new disease that appeared at the beginning of this century. It is now the commonest disease of the colon in the Western world, being found in 1 in 3 people of over 60 years of age. The pathogenesis of the disease involves excessive segmentation, but this does not explain its aetiology. The historical appearance of the disease on the clinical scene and its geographical distribution suggest that it is due to the removal of fibre from carbohydrates. The author treated 70 patients with symptomatic diverticular disease with a high-fibre diet. The results of this and the effects of bran are discussed.
Crohn's disease is a modern Western disease characterised by transmural inflammation of the gastrointestinal tract. It is of unknown aetiology, but evidence suggests that it results from a combination of genetic predisposition and environmental factors. Bacterial-sized microparticles (0.1-1.0 microm) are potent adjuvants in model antigen-mediated immune responses and are increasingly associated with disease. Microparticles of TiO2 and aluminosilicate accumulate in macrophages of human gut-associated lymphoid tissue where the earliest signs of lesions in Crohn's disease are observed. Dietary microparticles are of endogenous or exogenous origin. Endogenous microparticles dominate and are calcium phosphate (most probably hydroxyapatite), which precipitates in the lumen of the mid-distal gastrointestinal tract due to secretion of Ca and phosphate in the succus entericus. Exogenous dietary microparticles are contaminants (soil and/or dust) and food additives. TiO2, for example, is a food colourant, and aluminosilicates are anti-caking agents, although some aluminosilicates occur as natural contaminants. Food additives alone account for ingestion of approximately 10(12) particles/person per d. Possible mechanisms for the role of exogenous and endogenous dietary microparticles in promoting toleragenic or immune responses of gastrointestinal mucosal phagocytosis are discussed. In a double-blind randomised pilot study we have shown that a diet low in Ca and exogenous microparticles appears to alleviate the symptoms of ileal Crohn's disease, with a significant (P= 0.002) improvement in the Crohn's disease activity index. A multi-centre trial and further mechanistic studies at the cellular level are underway.
OBJECTIVES: It has been reported that a number of children with constipation respond to a diet free of cow's-milk (CM) proteins, although evidence is lacking to support an immunoglobulin E-mediated mechanism. PATIENTS AND METHODS: We performed an open-label crossover study comparing CM and rice milk in 69 children who fulfilled Rome III criteria for chronic constipation. Clinical, physical, and immunologic parameters of patients who responded (R) and who did not respond (NR) to a CM-free diet were compared. RESULTS: Thirty-five of the 69 children (51%) improved during the first CM-free diet phase, 8 of these did not develop constipation when CM was reintroduced, and 27 children (39%) developed constipation during the CM challenge and improved during the second CM-free diet phase (R group). Thirty-four children (49%) did not improve during the first CM-free diet phase (NR group). Bowel movements per week among R children significantly increased compared with NR children (R: 2.8-7.7 vs NR: 2.6-2.7) (P < 0.001). Seventy-eight percent of the children with developmental delay responded to the CM-free diet (P = 0.007). No significant statistical difference was found between the R and NR children in terms of fiber and milk consumption; atopic or allergic history; full-blood eosinophil count and percentage, and lymphocyte populations; immunoglobulins, immunoglobulin (Ig)G subclasses, total IgE; and serum-specific immunoglobulin E for CM proteins. CONCLUSIONS: A clear association between CM consumption and constipation has been found in more than one third of children. However, analytical parameters do not demonstrate an immunoglobulin E-mediated immunologic mechanism.
The relation between epithelial dysplasia in nipple aspirates of breast fluid and frequency of bowel movements was studied in 1481 white women. There was a significant positive association with dysplasia (risk ratio 4.5; 95% confidence interval 1.9-11.9) in women reporting severe constipation, i.e., two or fewer bowel movements weekly, which was not seen in women reporting more than one bowel movement daily. Women who had one bowel movement daily or one every other day had increased risk ratios. Cytological abnormalities in breast epithelium associated with severe constipation may be relevant to studies of diet and breast disease since the intestinal flora has been reported to metabolism bile salts and oestrogens secreted by the liver into the gastrointestinal tract-a process which may be enhanced by severe constipation.
A study is reported in which the prevalence of symptomless diverticular disease of the colon is related to the consumption of dietary fibre in vegetarians and non-vegetarians. Vegetarians had a significantly higher mean fibre intake (41.5 g/day) than non-vegetarians (21.4 g/day). Diverticular disease was commoner in non-vegetarians (33%) than in vegetarians (12%). Comparison of subjects with and without diverticular disease in the vegetarian and non-vegetarian groups provided some further evidence that a low intake of cereal fibre is associated with the presence of diverticular disease.
Fourteen sites evenly divided between the household kitchen and bathroom were monitored on a weekly basis for numbers of faecal coliforms, total coliforms and heterotrophic plate count bacteria. The first 10 weeks comprised the control period, hypochlorite cleaning products were introduced into the household during the second 10 weeks, and a strict cleaning regimen using hypochlorite products was implemented during the last 10 weeks. The kitchen was more heavily contaminated than the bathroom, with the toilet seat being the least contaminated site. The highest concentrations of all three classes of bacteria were found on sites that were moist environments and/or were frequently touched; these included the sponge/dishcloth, the kitchen sink drain area, the bath sink drain area, and the kitchen faucet handle(s). The implementation of a cleaning regimen with common household hypochlorite products resulted in the significant reduction of all three classes of bacteria at these four sites and other household sites.
BACKGROUND: Celiac disease (CD) is an immune-mediated enteropathic condition triggered in genetically susceptible individuals by the ingestion of gluten. Although common in Europe, CD is thought to be rare in the United States, where there are no large epidemiologic studies of its prevalence. The aim of this study was to determine the prevalence of CD in at-risk and not-at-risk groups in the United States. METHODS: Serum antigliadin antibodies and anti-endomysial antibodies (EMA) were measured. In EMA-positive subjects, human tissue transglutaminase IgA antibodies and CD-associated human leukocyte antigen DQ2/DQ8 haplotypes were determined. Intestinal biopsy was recommended and performed whenever possible for all EMA-positive subjects. A total of 13 145 subjects were screened: 4508 first-degree and 1275 second-degree relatives of patients with biopsy-proven CD, 3236 symptomatic patients (with either gastrointestinal symptoms or a disorder associated with CD), and 4126 not-at-risk individuals. RESULTS: In at-risk groups, the prevalence of CD was 1:22 in first-degree relatives, 1:39 in second-degree relatives, and 1:56 in symptomatic patients. The overall prevalence of CD in not-at-risk groups was 1:133. All the EMA-positive subjects who underwent intestinal biopsy had lesions consistent with CD. CONCLUSIONS: Our results suggest that CD occurs frequently not only in patients with gastrointestinal symptoms, but also in first- and second-degree relatives and patients with numerous common disorders even in the absence of gastrointestinal symptoms. The prevalence of CD in symptomatic patients and not-at-risk subjects was similar to that reported in Europe. Celiac disease appears to be a more common but neglected disorder than has generally been recognized in the United States.
Until recently, reports on methicillin-resistant Staphylococcus aureus (MRSA) in food production animals were mainly limited to occasional detections in dairy cattle mastitis. However, since 2005 a MRSA clone, CC398, has been reported colonizing pigs, veal calves and broiler chickens and infecting dairy cows. Many aspects of its prevalence in pigs remain unclear. In other livestock, colonizing capacity and reservoir status still require elucidation. MRSA CC398 has also been detected in meat, but, as for other MRSA, the risk this poses is somewhat unclear. Currently, the most worrying aspect of MRSA CC398 appears to be its capacity to spread to humans. This might complicate MRSA control measures in human healthcare, urging research into risk factors and transmission routes. Although infections with MRSA CC398 are much less reported than carriage, more investigation into its pathogenic potential is required. Moreover, the origin and evolution of this clone remain unknown.
Closely related strains of Escherichia coli have been shown to cause extraintestinal infections in unrelated persons. This study tests whether a food reservoir may exist for these E. coli. Isolates from 3 sources over the same time period (2005–2007) and geographic area were compared. The sources comprised prospectively collected E. coli isolates from women with urinary tract infection (UTI) (n = 353); retail meat (n = 417); and restaurant/ready-to-eat foods (n = 74). E. coli were evaluated for antimicrobial drug susceptibility and O:H serotype and compared by using 4 different genotyping methods. We identified 17 clonal groups that contained E. coli isolates (n = 72) from >1 source. E. coli from retail chicken (O25:H4-ST131 and O114:H4-ST117) and honeydew melon (O2:H7-ST95) were indistinguishable from or closely related to E. coli from human UTIs. This study provides strong support for the role of food reservoirs or foodborne transmission in the dissemination of E. coli causing common community-acquired UTIs.
Crohn's disease is a complex inherited disorder of unknown pathogenesis with environmental, genetic and microbial factors involved in the development of the disease. A remarkable feature of this disease in childhood is the effective response to exclusive enteral nutrition (EEN) therapy and the need for complete exclusion of normal diet required for success (principle of exclusivity). EEN or dietary interventions might act through removal of dietary components, which affect microbial composition, decrease a proinflammatory response and promote restitution of the epithelial barrier, likewise allowing termination of this vicious disease-forming cycle before a critical threshold is reached. Multiple traditional and nontraditional dietary components may affect the microbiome, mucous layer, intestinal permeability, or adherence and translocation of pathobionts. We review the epidemiological data, as well as data from animal models and cell lines, and propose a model for pathogenesis we have termed the 'bacterial penetration cycle', whereby dietary components such as animal fat, high sugar intake and gliadin, and consumption of emulsifiers, maltodextrin as well as low-fiber diets may be able to cause a localized acquired bacterial clearance defect, leading to bacterial adhesion and penetration, and subsequently inflammation in the gut. © 2014 S. Karger AG, Basel.
Irritable bowel syndrome (IBS) is a common functional disorder of the gastrointestinal system, and is characterized by abdominal pain, diarrhea (IBS/D), constipation (IBS/C), and alternating diarrhea and constipation (IBSC/A). The purpose of this study was to examine the impact of a four week kiwifruit intervention on bowel function in patients diagnosed with IBS/C. Fifty-four patients with IBS/C and 16 healthy adults participated in this study. All subjects participated in the 6 week, three phase study, which included a baseline phase (1 week), a dietary intervention period (4 weeks), and a post-intervention phase (1 week). Forty-one IBS/C patients and all healthy adults consumed two Hayward green (Actinida deliciosa var) kiwifruits per day for 4 weeks. Thirteen IBS/C patients in the control group took two placebo capsules per day for 4 weeks. Colon transit time was measured immediately prior to and following the intervention period. All subjects completed daily defecation records. After the 4-week intervention, weekly defecation frequency significantly increased in the IBS/C group of participants who consumed kiwifruit (p<0.05). Colon transit time significantly decreased (p=0.026) in the IBS/C group that consumed kiwi fruit. These findings suggest that kiwifruit consumption for 4 weeks shortens colon transit time, increases defecation frequency, and improves bowel function in adults diagnosed with IBS/C.
Celiac disease (CD) is a gluten-dependent immune-mediated disease with a prevalence in the general population estimated between 0.3% and 1.2%. Large-scale epidemiological studies have shown that only 10-20% of cases of CD are identified on the basis of clinical findings and that laboratory tests are crucial to identify subjects with subtle or atypical symptoms. The correct choice and clinical use of these diagnostic tools may enable accurate diagnosis and early recognition of silent CD cases. In this review, we have considered some relevant aspects related to the laboratory diagnosis of CD and, more extensively, of gluten intolerance, such as the best combination of tests for early and accurate diagnosis, the diagnostic role of new tests for detecting antibodies against neoepitopes produced by the transglutaminase-gliadin complex, the forms of non-celiac gluten intolerance (gluten sensitivity), and the use and significance of measuring cytokines in CD.
In industrialized nations, diverticular disease affects up to 70% of individuals by 60 years of age, with symptoms that can range from mild gastrointestinal disturbance to incapacitating pain. Diverticular disease appears to be related to increasing affluence and changed diet: Current theory holds that diverticular disease's origin is low-fiber diet. This explains why its incidence is highest and accelerating in the more prosperous countries where intake of fiber has decreased and intake of milled grains and refined sugars has increased over time. Not all patients develop symptoms, but if they do, the most frequent complaints associated with diverticulosis are cramping in the left-lower quadrant, bloating, constipation, and soiling. If diverticula perforate the gut's wall into the pericolic tissue, small and large abscesses, accompanied by bleeding, can form. Fistulization, when it occurs, most often penetrates to the bladder. Treatment addresses symptoms and may require hospitalization. During symptomatic periods, patients do best on low-fiber, bland diets. Once the acute episode or highly symptomatic period resolves or chronic disease is managed, patients should gradually increase dietary fiber to 20 to 30 grams daily or take dietary fiber in the form of bulk stimulants like psyllium.
Phleboliths, and especially diverticular disease and hiatus hernia, are rarer in developing countries than in economically more developed communities, but all three conditions were as common in Black as in White Americans. This finding suggests that they are due to environmental rather than to genetic causes. A deficient intake of dietary fibre may be the common factor predisposing to these three conditions.
The incidence of colorectal cancer (CRC) is dramatically higher in African Americans (AAs) than in Native Africans (NAs) (60:100,000 vs. <1:100,000) and slightly higher than in Caucasian Americans (CAs). To explore whether the difference could be explained by interactions between diet and colonic bacterial flora, we compared randomly selected samples of healthy 50- to 65-y-old AAs (n = 17) with NAs (n = 18) and CAs (n = 17). Diet was measured by 3-d recall, and colonic metabolism by breath hydrogen and methane responses to oral lactulose. Fecal samples were cultured for 7-alpha dehydroxylating bacteria and Lactobacillus plantarum. Colonoscopic mucosal biopsies were taken to measure proliferation rates. In comparison with NAs, AAs consumed more (P < 0.01) protein (94 +/- 9.3 vs. 58 +/- 4.1 g/d) and fat (114 +/- 11.2 vs. 38 +/- 3.0 g/d), meat, saturated fat, and cholesterol. However, they also consumed more (P < 0.05) calcium, vitamin A, and vitamin C, and fiber intake was the same. Breath hydrogen was higher (P < 0.0001) and methane lower in AAs, and fecal colony counts of 7-alpha dehydroxylating bacteria were higher and of Lactobacilli were lower. Colonic crypt cell proliferation rates were dramatically higher in AAs (21.8 +/- 1.1% vs. 3.2 +/- 0.8% labeling, P < 0.0001). In conclusion, the higher CRC risk and mucosal proliferation rates in AAs than in NAs were associated with higher dietary intakes of animal products and higher colonic populations of potentially toxic hydrogen and secondary bile-salt-producing bacteria. This supports our hypothesis that CRC risk is determined by interactions between the external (dietary) and internal (bacterial) environments.
PURPOSE: The fecal-perineal-urethral hypothesis to explain the cause of urinary tract infections (UTI) by enteric bacteria has been supported by longitudinal studies using methods of serotyping and detecting urovirulence factors such as P fimbriae. However, genetic techniques to more accurately characterize Escherichia coli strains have not been exploited. MATERIALS AND METHODS: A total of 2,700 E. coli colonies isolated from the urine and rectal swabs of 9 female subjects with acute uncomplicated cystitis and from the rectal swabs of 30 healthy women were serotyped and examined for genes encoding various urovirulence factors by colony hybridization test. The clonality of the urine and fecal isolates of E. coli from the cystitis subjects was further evaluated by pulsed-field gel electrophoresis (PFGE). RESULTS: E. coli strains causing cystitis dominated the rectal flora of 7 of 9 patients. In the remaining 2 patients, similar clones comprised at least 20% of the fecal flora. Carriage of E. coli strains with a variety of urovirulence factors was quite common among healthy women. PFGE demonstrated that most of the isolates sharing the same serotypic characteristics and virulence factors in the urine and rectal swab samples from each subject were identical. CONCLUSIONS: Based upon precise genetic techniques, our results clearly support the fecal-perineal-urethral hypothesis, indicating that E. coli strains residing in the rectal flora serve as a reservoir for urinary tract infections, e.g., cystitis.
Mean faecal urobilinogen levels and the pH of stools were both found to be higher in subjects from a population group at high risk of developing cancer of the colon than in subjects matched for age, sex and socioeconomic status from a low-risk population group. An alkaline reaction of the colon contents seems to have a tumorigenic effect by a direct action on the mucus of the mucous cells. An acidic reaction, on the other hand, appears to be protective. These differences are dependent on the patterns of diet and manner of eating. Proper mastication of food, roughage, cellulose and vegetable fibre, and short-chain fatty acids of milk and fermented milk products in the diet appear to be protective.
Background & Aims The historical prevalence and long-term outcome of undiagnosed celiac disease (CD) are unknown. We investigated the long-term outcome of undiagnosed CD and whether the prevalence of undiagnosed CD has changed during the past 50 years. Methods This study included 9,133 healthy young adults at Warren Air Force Base (sera were collected between 1948 and 1954) and 12,768 sex-matched subjects from 2 recent cohorts from Olmsted County, Minnesota, with either similar years of birth (n=5,558) or age at sampling (n=7,210) to that of the Air Force cohort. Sera were tested for tissue transglutaminase and, if abnormal, for endomysial antibodies. Survival was measured during a follow-up period of 45 years in the Air Force cohort. The prevalence of undiagnosed CD between the Air Force cohort and recent cohorts was compared. Results Of 9,133 persons from the Air Force cohort, 14 (0.2%) had undiagnosed CD. In this cohort, during 45 years of follow-up, all-cause mortality was greater in persons with undiagnosed CD than among those who were seronegative (hazard ratio=3.9; 95% CI, 2.0–7.5; P<.001). Undiagnosed CD was found in 68 (0.9%) persons with similar age at sampling and 46 (0.8%) persons with similar years of birth. The rate of undiagnosed CD was 4.5-fold and 4-fold greater in the recent cohorts (respectively) than in the Air Force cohort (both P ≤ .0001). Conclusions During 45 years of follow-up, undiagnosed CD was associated with a nearly 4-fold increased risk of death. The prevalence of undiagnosed CD appears to have increased dramatically in the United States during the past 50 years.
Ciguatera fish poisoning (CFP) is a distinctive type of foodborne disease that results from eating predatory ocean fish contaminated with ciguatoxins. As many as 50,000 cases are reported worldwide annually, and the condition is endemic in tropical and subtropical regions of the Pacific basin, Indian Ocean, and Caribbean. In the United States, 5--70 cases per 10,000 persons are estimated to occur yearly in ciguatera-endemic states and territories. CFP can cause gastrointestinal symptoms (nausea, vomiting, abdominal cramps, or diarrhea) within a few hours of eating contaminated fish. Neurologic symptoms, with or without gastrointestinal disturbance, can include fatigue, muscle pain, itching, tingling, and (most characteristically) reversal of hot and cold sensation. This report describes a cluster of nine cases of CFP that occurred in North Carolina in June 2007. Among the nine patients, six experienced reversal of hot and cold sensations, five had neurologic symptoms only, and overall symptoms persisted for more than 6 months in three patients. Among seven patients who were sexually active, six patients also complained of painful intercourse. This report highlights the potential risks of eating contaminated ocean fish. Local and state health departments can train emergency and urgent care physicians in the recognition of CFP and make them aware that symptoms can persist for months to years.
Because the range of bowel habits and stool types in the community is unknown we questioned 838 men and 1059 women, comprising 72.2% of a random stratified sample of the East Bristol population. Most of them kept records of three consecutive defecations, including stool form on a validated six point scale ranging from hard, round lumps to mushy. Questionnaire responses agreed moderately well with recorded data. Although the most common bowel habit was once daily this was a minority practice in both sexes; a regular 24 hour cycle was apparent in only 40% of men and 33% of women. Another 7% of men and 4% of women seemed to have a regular twice or thrice daily bowel habit. Thus most people had irregular bowels. A third of women defecated less often than daily and 1% once a week or less. Stools at the constipated end of the scale were passed more often by women than men. In women of child bearing age bowel habit and the spectrum of stool types were shifted towards constipation and irregularity compared with older women and three cases of severe slow transit constipation were discovered in young women. Otherwise age had little effect on bowel habit or stool type. Normal stool types, defined as those least likely to evoke symptoms, accounted for only 56% of all stools in women and 61% in men. Most defecations occurred in the early morning and earlier in men than in women. We conclude that conventionally normal bowel function is enjoyed by less than half the population and that, in this aspect of human physiology, younger women are especially disadvantaged.
Sixty percent of the U.S. population experiences acute diarrheal illness each year, but little is understood regarding public knowledge and beliefs about the causes and treatment of these diseases. We performed a telephone survey of 2117 Tennessee residents regarding knowledge and practices associated with diarrheal illness. Bloody stool, dehydration, and persistent symptoms were the most common reasons for which the respondents would seek medical care. Although most acute diarrheal disease is self-limited, overuse of antimicrobials for treatment is common. Few people believed that stool cultures (4.5%) or antibiotics (6.9%) are routinely necessary for diarrhea. Over 60% of respondents believed that food is the most common source of diarrhea. Three-fourths believed that it is normal for uncooked meat to contain bacteria, and 45% believed it is legal to sell such products. These results have implications for medical providers, regulators, and public health in the management and prevention of diarrheal disease.
OBJECTIVE: To investigate whether the rarity of colon cancer in black Africans (prevalence, < 1:100,000) can be accounted for by dietary factors considered to reduce risk, and by differences in colonic bacterial fermentation. METHODS: Samples of the adult black South African population were drawn from several rural and urban regions. Food consumption was assessed by home visits, food frequency questionnaires, computerized analysis of 72-h dietary recall, and blood sampling. Colonic fermentation was measured by breath H2 and CH4 response to a traditional meal, and to 10-g of lactulose. Cancer risk was estimated by measurement of epithelial proliferation indices (Ki-67 and BrdU) in rectal mucosal biopsies. Results were evaluated by comparison to measurements in high-risk white South Africans (prevalence, 17:100,000). RESULTS: Epithelial proliferation was significantly lower in rural and urban blacks than whites. The diets of all the black subgroups were characterized by a low animal product and high boiled maize-meal content, whereas whites consumed more fresh animal products, cheese, and wheat products. Blacks consumed below RDA quantities of fiber (43% of RDA), vitamin A (78%), C (62%), folic acid (80%) and calcium (67%), whereas whites consumed more animal protein (177% of RDA) and fat (153%). Fasting and food-induced breath methane production was two to three times higher in blacks. CONCLUSIONS: The low prevalence of colon cancer in black Africans cannot be explained by dietary "protective" factors, such as, fiber, calcium, vitamins A, C and folic acid, but may be influenced by the absence of "aggressive" factors, such as excess animal protein and fat, and by differences in colonic bacterial fermentation.