Resistant starch modifies gut microflora and microbial metabolism in human flora-associated rats inoculated with faeces from Italian and UK donors

The effect of sucrose and resistant starch ('CrystaLean'--a retrograded, amylose starch) on human gut microflora and associated parameters was studied in human flora-associated (HFA) rats, colonized with microfloras from UK or Italian subjects, to determine whether such floras were affected differently by dietary carbohydrates. Consumption of the resistant starch diet resulted in significant changes in four of the seven main groups of bacteria enumerated. In both the UK and Italian flora-associated rats, numbers of lactobacilli and bifidobacteria were increased 10-100-fold, and there was a concomitant decrease in enterobacteria when compared with sucrose-fed rats. The induced changes in caecal microflora of both HFA rat groups were reflected in changes in bacterial enzyme activities and caecal ammonia concentration. Although it had little effect on caecal short-chain fatty acid concentration, CrystaLean markedly increased the proportion of n-butyric acid in both rat groups and was associated with a significant increase in cell proliferation in the proximal colon of the Italian flora-associated rats. CrystaLean appeared to play a protective role in the colon environment, lowering caecal ammonia concentration, caecal pH and beta-glucuronidase activity.

In vitro evaluation of antimicrobial activity of Lactobacillus rhamnosus IMC 501(®) , Lactobacillus paracasei IMC 502(®) and SYNBIO(®) against pathogens

AIMS

Probiotic lactobacilli have a great potential to produce antimicrobial compounds that inhibit and control the microbial pathogen growth. The antimicrobial and antifungal activities of two probiotic strains, Lactobacillus rhamnosus IMC 501(®) and Lactobacillus paracasei IMC 502(®) , and their 1 : 1 combination, named SYNBIO(®) , were studied using four different methods.

METHODS AND RESULTS

Using two modified streak methods and a well diffusion method, the inhibitory activity of the probiotics and their metabolites towards six Gram-positive, nine Gram-negative pathogenic bacterial strains and eight Candida strains was tested. Antagonistic effect of probiotic Lactobacillus strains was also investigated by coculturing assay highlighting a significant inhibition of most of the pathogens tested in this study. The combination SYNBIO(®) showed a microbicidal activity against most of the strains tested in the study.

CONCLUSIONS

Compared with the control, most of the pathogenic bacteria and yeast were inhibited by all probiotic strains tested to various degrees.

SIGNIFICANCE AND IMPACT OF THE STUDY

Screening Lactobacillus strains according to their activity in various environmental conditions could precede the clinical efficacy studies for adjunct treatment with probiotics in cure of different gastrointestinal and vaginal tract infections.

Abusive use of antibiotics in poultry farming in Cameroon and the public health implications

The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

Efficacy of antimicrobial filter treatments on microbial colonization of air panel filters

AIMS

To assess the activity of biostatic agents on the microbial colonization of panel filters.

METHODS AND RESULTS

Microfibre glass acrylic filters, both used and unused, were examined for the presence of microorganisms. Test strains were used to verify microbial colonization of filter media. Antimicrobial agents were applied to the filter media and tested for their ability to reduce microbial colonization. The integrity of the panel filters and the antimicrobial activity trends of the filter media treated with antimicrobials were verified. A filtration efficiency test was carried out on the treated filters to evaluate filtration performance. Filters treated with antimicrobials demonstrated markedly less microbial colonization (density and varieties of species), higher filtration efficiency and delayed deterioration of the filter.

CONCLUSIONS

The most important results of this study are the demonstration of preservation of the integrity of the filters and the lower release of microorganisms from treated filters.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results contribute to the resolution of problems concerning the microbial contamination of panel filters in the heating, ventilating and air-conditioning systems commonly used in the electronic industry, pharmaceutical industry, hospitals and other environments where the absence of contaminating particles and microorganisms is required.

The effect of sucrose or starch-based diet on short-chain fatty acids and faecal microflora in rats

An investigation was carried out to determine whether variations of dietary carbohydrates could modify the colonic flora in rats. Sprague-Dawley rats were fed with two equicaloric diets based on the AIN-76 diet (American Institute of Nutrition 1977) but differing from that diet in content of carbohydrates, i.e. high sucrose (64%) of high corn starch (64%). Feeding was continued for 9 months ad libitum and no variation in weight gain was recorded among the different diets. A prevalence of aerobes, and a significant reduction in the ratio anaerobes/aerobes in the faeces of rats on the high starch diet compared with the high sucrose diet, was observed. The anaerobe genera identified included Actinomyces, Bacteroides, Bifidobacterium, Clostridium, Eubacterium, Lactobacillus and Propionibacterium. Bacteroides was the most prevalent genus in both dietary groups (51.2 and 29.5% in the faeces of rats fed the sucrose and starch diets, respectively). In contrast, clostridia were prevalent in the starch-fed group (23.8%) and less so in the sucrose diet (11.5%), as propionibacteria were prevalent in faeces of rats fed the starch diet (15.5%), and low in the sucrose diet (3.9%). The remaining genera were scarce in faeces from rats on either diet. Total short-chain fatty acids (SCFA) were significantly higher in the faeces of animals fed the starch diet compared with those fed the sucrose diet. The relative concentrations of acetic, propionic and butyric acids were not significantly different between the two dietary groups. In conclusion, high starch diet can markedly modify the composition of faecal flora and alter considerably the faecal concentration of SCFAs, compound which might have a health-promoting effect.

Influence of a combination of two potential probiotic strains, Lactobacillus rhamnosus IMC 501® and Lactobacillus paracasei IMC 502® on bowel habits of healthy adults

AIMS

This study aims to investigate the effect of different kinds of food products enriched with a combination of two potential probiotic strains, Lactobacillus rhamnosus IMC 501(®) and Lactobacillus paracasei IMC 502(®), on bowel habits of healthy adults.

METHODS AND RESULTS

Fifty healthy volunteers took part in a double-blind placebo probiotic feeding study (25 fed probiotics, 25 fed placebo) for 12 weeks. Each volunteer ingested daily one or more food products enriched with a combination of the two potential probiotic strains (probiotic group) or the same food products without the probiotics (control group). Faecal samples were collected before, at the end and 2 weeks later the intervention period, and some of the main groups of faecal bacteria were enumerated by plate count and real-time PCR. Questionnaires on bowel habits were submitted to volunteers. After the intervention, a significant increase in faecal lactobacilli and bifidobacteria were observed in the probiotic group, and stool frequency and stool volume were higher in the probiotic group than in the placebo group.

CONCLUSIONS

Daily consumption of food products enriched with the two potential probiotic strains, Lact. rhamnosus IMC 501(®) and Lact. paracasei IMC 502(®) , contributes to improve intestinal microbiota with beneficial properties and enhances bowel habits of healthy adults.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study revealed that Lact. rhamnosus IMC 501(®) and Lact. paracasei IMC 502(®) exert a positive effect, in terms of improved bowel habits, on healthy adults.

Effects of antimicrobial treatment on fiberglass-acrylic filters

AIMS

The aims of the present study were to: (i) analyse a group of antimicrobial agents and to select the most active against test microbial strains; (ii) test the effect of the antimicrobial treatment on air filters in order to reduce microbial colonization.

METHODS AND RESULTS

Different kinds of antimicrobial agents were analysed to assess their compatibility with the production process of air filter media. The minimal inhibitory concentration for each antimicrobial agent was determined against a defined list of microbial strains, and an antimicrobial activity assay of filter prototypes was developed to determine the most active agent among the compatible antimicrobials. Then, the most active was chosen and added directly to the filter during the production process. The microbial colonization of treated and untreated filter media was assessed at different working times for different incubation times by stereomicroscope and scanning electron microscope analysis. Some of the antimicrobial agents analysed were more active against microbial test strains and compatible with the production process of the filter media. Filter sections analysis of treated filter media showed a significantly lower microbial colonization than those untreated, a reduction of species both in density and varieties and of the presence of bacteria and fungal hyphae with reproductive structures.

CONCLUSIONS

This study demonstrated the ability of antimicrobial treatments to inhibit the growth of micro-organisms in filter media and subsequently to increase indoor air quality (IAQ), highlighting the value of adding antimicrobials to filter media.

SIGNIFICANCE AND IMPACT OF THE STUDY

To make a contribution to solving the problem of microbial contamination of air filters, by demonstrating the efficacy of incorporating antimicrobial agents in the filter media to improve IAQ and health.

In vitro evaluation on HeLa cells of protective mechanisms of probiotic lactobacilli against Candida clinical isolates

AIMS

To characterize in vitro the ability of human Lactobacillus strains to inhibit the adhesion, to displace and to compete with clinically isolated Candida strains.

METHODS AND RESULTS

Three types of assays were performed to determine the inhibitory effect of Lactobacillus plantarum 319, Lactobacillus rhamnosus IMC 501, Lactobacillus paracasei IMC 502 and a specific probiotic combination (SYNBIO) on adhesion of Candida pathogens to HeLa cells: blockage by exclusion (lactobacilli and HeLa followed by pathogens), competition (lactobacilli, HeLa and pathogens together) and displacement (pathogens and HeLa followed by the addition of lactobacilli). Bacterial adhesion to HeLa was quantified by microscopy after May-Grünwald/Giemsa stain. The inhibition results highlight a significant (P < 0·05) competition of the considered probiotics against all the Candida strains. The results suggest that the probiotic strains used in this study could prevent colonization of the urogenital tract by relevant pathogens such as Candida strains through barrier and interference mechanisms (mainly displacement and competition), but the degree of inhibition of adhesion was bacterial strain-dependent.

CONCLUSIONS

The results support the potential of these Lactobacillus probiotic strains as anti-infective agents in the vagina and encourage further studies about their capacity to prevent and manage urogenital tract infections in females.

SIGNIFICANCE AND IMPACT OF THE STUDY

To optimize the defensive properties of the vaginal microbiota, improving the health of many women by probiotic intervention.

Trends of lung cancer mortality in Italy in relation to consumption of tobacco products

This paper examines changes with time of mortality from lung cancer in Italy during the years 1950-1979 in relation to changes in smoking habits since 1900. In both sexes and for all ages mortality rose throughout this period, although for women the rates and the relative increases per year have been consistently much lower than for men. Between 1950-1952 and 1977-1979 the age-adjusted death rate per 100,000 men rose almost five times (from 10.01 to 49.55) whereas that for women only doubled (from 2.65 to 5.74), so that the male/female ratio increased from 3.78 to 8.65. In men successive cohorts show an increase of age-specific death rate, but there are indications that for men born after 1925 the mortality rate is beginning to level off. In women over 50 years of age mortality continues to rise, but below this age it tends to level off and decline. Analysis of the consumption of different types of tobacco products since 1900 suggests that the trends of mortality with time in different birth cohorts are explicable in terms of changes of use of cigarettes.

Antimicrobial activity of SYNBIO® probiotic formulation in pathogens isolated from chronic ulcerative lesions: in vitro studies

AIMS

Probiotics have the ability to enhance the immune system, produce anti-inflammatory action and promote wound healing process. The first aim of the study was to isolate pathogenic micro-organisms from sites of chronic ulcerative lesion. The second aim was to evaluate probiotic efficacy of SYNBIO^® (1:1 combination of Lactobacillus rhamnosus IMC 501^® and Lactobacillus paracasei IMC 502^® ) in counteracting wound infections.

METHODS AND RESULTS

Several bacterial pathogens were isolated from chronic ulcerative lesions and identified by morphological, biochemical and molecular techniques. SYNBIO^® probiotic formulation was investigated for its antimicrobial activity, minimum inhibitory concentration, co-aggregation and adherence capacity against the isolated pathogens. Moreover, SYNBIO was also tested in combination with some medical devices, using an in vitro model, in order to simulate a real ulcerative wound infection. Probiotic formulation demonstrated an inhibitory action against all the tested pathogens and their mixture (MIX), with an increased ability of co-aggregation during time. In addition, the adhesion percentage of probiotic micro-organisms to human keratinocyte (HaCaT cells) and human fibroblasts (NHF), calculated by an in vitro model, was 19% and 17% respectively, highlighting the possibility to create a protective environment preventing pathogens' biofilm formation in order to contrast infections.

CONCLUSIONS

SYNBIO^® probiotics showed a very good antimicrobial capacity and adhesion percentage to HaCaT cells and fibroblasts, giving the opportunity to be successfully used as complement to conventional therapies in the treatment of chronic ulcerative lesions.

SIGNIFICANCE AND IMPACT OF THE STUDY

A new therapeutic approach with probiotics (supplemented in topical applications, excluding side effects) able to eliminate pathogenic micro-organisms and improve healing of chronic ulcerative lesions.

Esophageal cancer mortality: relationship with alcohol intake and cigarette smoking in Italy

This paper examines changes with time in age-adjusted mortality from esophageal cancer for the years 1950-1981, in relation to changes in smoking habits and alcohol consumption. In both sexes the age-adjusted death rates have shown no marked time variation. Instead in the same period there have been marked temporal variations in consumption of alcohol and tobacco which are considered risk factors associated with esophageal cancer. The male cohort variation seems to indicate some fluctuations in mortality before 1921 and a progressive increase after this year. In females the death rates are very low and the cohort variation is practically constant. The progressive increase of cohort variation in esophageal cancer mortality for men born after 1921 coincides with a progressive increase in hard alcohol consumption. In the same period there has also been a progressive increase in tobacco consumption but this begun at the turn of this century.

Mortality from cancer of the digestive system in Italy: 1950-1975 cross-sectional rates and cohort analysis

In this study of mortality from cancer of the digestive system in Italy, 1950-1975, both cross-sectional rates and cohort analysis were used. The study found that in both sexes age-standardized rates for cancer of the colon, rectum, liver and biliary tract, and pancreas are increasing whereas the rates for cancer of the stomach are decreasing. Rates for esophagus cancer have remained fairly constant. Cohort analysis showed different trends for selected sites. As to cancer of the stomach, for both sexes, cohorts born up until about 1881 have constant or increasing rates; cohorts born after 1881 have declining rates. For cancer of the esophagus in males the rates reach a peak in the 1896 birth-cohort; cohorts born prior to 1896 show an increase in rates and cohorts born later show a decline. For cancer of the colon, liver and biliary tract, and pancreas, the rates rise constantly for all ages and all cohorts in both sexes. The rates for cancer of the rectum rise after age 75 whereas below that age the rates tend to level off and decline.

Modification of azoxymethane intestinal carcinogenesis in rats by feeding sucrose boluses, pasta, and glucose

We studied whether repeated boluses of sucrose or diets containing carbohydrates with a variable glycemic index (GI) affect intestinal carcinogenesis in rats. Male F344 rats were treated twice (1 wk apart) with 15 mg/kg sc azoxymethane (AOM) and then divided into four experimental dietary groups with different carbohydrate composition and administration schedules: the sucrose group was fed 44% (wt/wt) sucrose (GI = 65), the bolus group was fed sucrose as carbohydrate and 43 boluses of sucrose (10-15 g/kg) at various time intervals, the pasta group was fed pasta [77% (wt/wt) cooked pasta, GI = 55], and the glucose group was fed 44% (wt/wt) glucose (GI = 97). All nutrients, including carbohydrates, were provided in similar amount to the different groups. The experiment was terminated between Day 230 and Day 245 after AOM administration. At this time the pasta group had significantly higher cecal short-chain fatty acids than the other groups. Intestinal adenomas and cancers occurred with the same frequency in the bolus, sucrose, and glucose groups. On the contrary, we observed a significant decrease (p = 0.03) in the cumulative incidence of intestinal adenomas, but not adenocarcinomas, in the pasta group compared with the sucrose group (intestinal adenoma incidence in the pasta group was 31% compared with 63% in the sucrose group, 46% in the bolus group, and 37% in the glucose group). In conclusion, these results do not support the hypothesis that sucrose boluses or carbohydrates with a high GI stimulate colon carcinogenesis, but they indicate that foods such as pasta may exert a protective effect.

Mortality from prostate cancer in Italy: 1950-1979. Cross-sectional rates and cohort analysis

This paper studies prostate cancer mortality in Italy from 1950-1979 to evaluate its importance in relation to total cancers, examine the time trend for forecasting future mortality trends, and makes an attempt to interpretate mortality by analyzing demographic and risk factors. In the Authors' opinion findings from cross-sectional rates, cohort analysis and Devesa-Schneiderman method, indicate that in Italy even if the age-adjusted mortality rate has nearly doubled over the period, as in many other countries, mortality can be expected to remain constant or decrease in the future, since the data to hand show a decreasing trend in some age cohorts.

[Characterization of species of the genus Clostridium by gas chromatographic analysis of the fatty acids produced during metabolism]

Volatile and non volatile fatty acids deriving from the bacterial metabolism of different sugars were determined by gas-chromatography to better characterize Clostridium tertium and Clostridium ramosum. The data obtained were also used for numerical taxonomic analysis and dendrograms were elaborated to study the taxonomic relationships between the two species.

[Sero-epidemiological studies of the anti-rubella immunological status of a sample of the female population]

A retrospective study on the prevalence and distribution of haemoagglutination inhibiting rubella antibodies in a sample of 4493 women (3150 in pregnancy), showed a low percentage of vaccinated women ( 0.6%) and high share of negative sera (12.6%). The Authors carried on the analysis subdividing the data according to age of the women, their pregnancy's condition or quarter, their residence (Rome and out of Rome) and occupation (housewife and not). The Pearsonian chi-square showed a significant difference between the lower immunization of housewife group and that of non-housewife group. Moreover the seropositivity decreases according to aging.

Gastric and lung cancer mortality in the Marche region of Italy, 1980-1983

This paper describes patterns in gastric and lung cancer mortality in the Marche region of Italy and in its 24 Local Health Districts (LHD) over the period 1980-83. Mortality data were obtained from the magnetic tapes provided by the National Institute of Statistics. Linear regressions were tested with the aim to relate the AADRs with the proportion of the agricultural workers in the 1951, 1961 and 1971 census years. The results obtained show that, in the whole Marche region, mortality from lung cancer is first in male cancer mortality. However within the Region itself many LHDs had different patterns. Among the LHDs, gastric cancer rates were the highest in some northern mountain zones, and lung cancer rates in some central coastal zones. Statistical analyses emphasize the inverse relationship between the male 0-64 AADRs relative to gastric cancer and those of lung cancer in the 24 LHDs. Among these, the male gastric cancer 0-64 AADRs are significantly and directly related to the proportion of farm workers in 1971, and the female ones to the proportion of farm workers in all the three periods, which in turn are always inversely related to the 0-64 AADRs male lung cancer. The differences between the observed and expected death frequencies in the several LHDs stress the results obtained in the present study, which generally agree with those obtained in other studies regarding the same and neighbouring areas and with those reported by the international literature.

[Salmonella isolated in the province of Macerata and their sensitivity to some common chemoantibiotics and to some of recent clinical introduction]

A study has been carried out in order to evaluate the sensitivity of a group of some 215 Salmonella strains identified in the triennium 1976-1978, in the district of Macerata (Italy), to 16 chemoantibiotics. The average percentage of sensitivity to chemoantibiotics, as a whole, vary from 100% (sisomycin) to 81% (furazolidone). The global sensitivity of different strains, of early diffusion and recent appearance in Italy, by MIC and MBC estimated, progressively increase as follow: A. wien, typhi, typhimurium, infantis, braenderup, paratyphi B, enteritidis, agona, panama.

Characterization of some Clostridium species by gas-liquid chromatography using numerical analysis

We studied 42 strains of Clostridia belonging to 20 different species. All the strains were examined for morphological characters, biochemical reactions, and analyzed by means of gas-liquid chromatography (GLC) to determine metabolic patterns of short chain fatty acids and alcohols. To increase the number of criteria for the differentiation, specimens were grown on Peptone Yeast Extract medium (PY) with the addition of 13 different carbohydrates. The strains were compared using numerical taxonomic techniques based upon 20 unit qualitative and 224 quantitative characters. Data were examined using the simple matching coefficient (SSM) for qualitative characters, and degree of overlap between superimposed trace (So) for qualitative characters, and clustering was achieved using the unweighted pair group method with arithmetic averages (UPGMA) technique. DNA base composition was also determined. Numerical analysis showed remarkable difference between phenograms derived from SSM and So coefficients. The phenogram (SSM) is formed by 11 clusters and eight of these include strains from only one species. Only three clusters contained strains from different species. The cluster variability range of G + C base composition was never higher than 4 mol% except for one cluster where it reached 7 mol% G + C. In the phenogram (So) instead, there are 8 clusters and in only one case are strains from one species aggregated. In the remaining 7 clusters strains belonging to two or more species aggregated. The range values of base composition are over 4 mol% in three of the eight clusters.