A microbiological assay method for p-aminobenzoic acid

Since the establishment of p-aminobenzoic acid as a member of the B vitamin group, a considerable interest has been shown in methods of determination in natural materials. Since known chemical methods are not sufficiently sensitive, it became evident that microbiological tests should be the most practicable. The organism Clostridium acetobutylicum has been used (1) but no general assay procedure has been presented. Several bacterial strains which respond to p-aminobenzoic acid have been investigated in this laboratory, but satisfactory assay procedures with these organisms have not yet been devised. For the discovery of the test organism used in the procedure described in this paper, we are indebted to Dr. Beadle and Dr. Tatum who kindly furnished us with a culture of their p-aminobenzoic acid requiring a mutant strain of Neurospora crassa, designated by them as Neurospora crassa p-aminobenzoicless No. 1633 (2). This mold will grow optimally on a medium consisting of inorganic salts, ammonium tartrate, sucrose, biotin, and p-aminobenzoic acid. For purposes of assay, however, it has proved advantageous to supplement this basal medium with natural extracts which are either naturally low in p-aminobenzoic acid or have been treated to remove it. With such a complex medium, the possibility of interference by toxic substances or stimulatory substances other than p-aminobenzoic acid which might be present in samples to be assayed is reduced to a minimum. Since the completion of a considerable part of the experimental work described in this paper, microbiological assay methods for p-aminobenzoic acid have been published by Landy and Dicken (3) utilizing the organism Acetobacter suboxydans and by Lewis (4) using Lactobacillus arabinosus 17-5

Biotimer assay: A reliable and rapid method for the evaluation of central venous catheter microbial colonization

Adherent bacteria and biofilm frequently colonize central venous catheters (CVCs). CVC colonization is correlated to infections and particularly to bloodstream ones. The classical microbiological methods to determine of CVC colonization are not fully reliable and are time-consuming. BioTimer Assay (BTA) is a biological method already used to count bacteria adherent to abiotic surfaces and biofilm without sample manipulation. BTA employs specific reagents whose color changed according to bacterial metabolism. BTA is based on the principle that a metabolic reaction will be faster when more bacteria are present in the sample. Therefore, the time required for color changes of BTA reagents determines the number of bacteria present in the sample through a correlation line. Here, for the first time, we applied BTA and a specifically developed laboratory procedure to evaluate CVC colonization in comparison with the routine microbiological method (RMM). 125 CVCs removed from patients for suspected catheter-related bloodstream infection (CRBSI) or at hospital discharge were examined. BTA was reliable in assessing sterility and CVC colonization (100% agreement with RMM) and in recognizing the presence of fermenting or non-fermenting bacteria (97.1% agreement with RMM) shortening the analytical time by between 2- and 3-fold. Moreover, the reliability of BTA as early alert of CRBSI was evaluated. The sensitivity, specificity, positive, and negative predictive values for BTA as an early alert of CRBSI were 100, 40.0, 88.8 and 100%, respectively. In conclusion, BTA and the related laboratory procedure should be incorporated into routine microbiological methods since it can be considered a reliable tool to evaluate CVC colonization in a very short time and a rapid alert for CRBSIs

Microbiological, chemical and physical quality of drinking water for commercial turkeys: a cross-sectional study.

open9Drinking water for poultry is not subject to particular microbiological, chemical and physical requirements, thereby representing a potential transmission route for pathogenic microorganisms and contaminants and/or becoming unsuitable for water-administered medications. This study assessed the microbiological, chemical and physical drinking water quality of 28 turkey farms in North-Eastern Italy: 14 supplied with tap water (TW) and 14 with well water (WW). Water salinity, hardness, pH, ammonia, sulphate, phosphate, nitrate, chromium, copper and iron levels were also assessed. Moreover, total bacterial count at 22°C, presence and enumeration of Enterococcus spp. and E. coli, presence of Salmonella spp. and Campylobacter spp. were quantified. A water sample was collected in winter and in summer at 3 sampling sites: the water source (A), the beginning (B) and the end (C) of the nipple line (168 samples in total). Chemical and physical quality of both TW and WW sources was mostly within the limits of TW for humans. However, high levels of hardness and iron were evidenced in both sources. In WW vs. TW, sulphate and salinity levels were significantly higher, whilst pH and nitrate levels were significantly lower. At site A, microbiological quality of WW and TW was mostly within the limit of TW for humans. However, both sources had a significantly lower microbiological quality at sites B and C. Salmonella enterica subsp. enterica serotype Kentucky was isolated only twice from WW. Campylobacter spp. were rarely isolated (3.6% of farms); however, Campylobacter spp. farm-level prevalence by real-time PCR was up to 43% for both water sources. Winter posed at higher risk than summer for Campylobacter spp. presence in water, whereas no significant associations were found with water source, site, recirculation system, and turkey age. Low salinity and high hardness were significant risk factors for C. coli and C. jejuni presence, respectively. These results show the need of improving sanitization of drinking water pipelines for commercial turkeys.openDi Martino G., Piccirillo A., Giacomelli M., Comin D., Gallina A., Capello K., Buniolo F., Montesissa C., Bonfanti L.Di Martino, G.; Piccirillo, A.; Giacomelli, M.; Comin, D.; Gallina, A.; Capello, K.; Buniolo, F.; Montesissa, C.; Bonfanti, L

Investigation of the Influence of Antioxidant Compositions on Development of Microbiological Spoilage in Storage of Fruits

The studies are devoted to the scientific grounding of expedience of after-harvest processing by antioxidant compositions for preventing the development of pathogenic microflora on fruit surfaces during a long storage. For the studies were used apple fruits of the varieties Aidared, Golden Dushesse, Renet Simirenka, pear fruits of the varieties Victoria, Crimea Raisin and Cure, plum fruits of the varieties Voloshka, Stanley and Italian Ugorka. Fruits were processed by immersion in the following antioxidant compositions: ACM is a mixture of dimethyl sulfoxide, ionol and polyethylene glycols; AARL – mixture of ascorbic acid, routin and lecithin; DL – mixture of dimethyl sulfoxide, ionol and lecithin. Fruits, processed by water, were used as a control. Exposition - 10 seconds. Storage was carried out at the temperature 0±1 ºС, relative air humidity 90–95 %. It was established that in the period of fruits laying for storage, the mean amount of epiphyte microflora was fixed on surfaces of plump and pear fruits of the mean ripening term. In the variety composition of epiphyte microflora prevailed spores of mesophyl aerobic and facultative-anaerobic microorganisms. Their mean number on apple fruits surface was 9,6·103 CCU/g, pear fruits – 10,6 103 CCU/g, plump fruits – 18·103CCCU/g. AOC processing of all types of fruits essentially decreased the speed of both MAFAnM and micromycetes growth. It was demonstrated that the used compositions in 2…3,5 times decreased the level of day losses from microbiological spoilage during the whole storage period. The most positive effect was received at using compositions, based on dystinol and lecithin. Multifactor analysis determined that the level of day losses from microbiological spoilage was mainly influenced by factors of raw material variety features (factor A) and antioxidant compositions processing (factor D). The shares of influence are 24 and 21 % respectively

Quality of High-protein Diet Bar Plus Chia (Salvia hispanica L.) Grain Evaluated Sensorially by Untrained Tasters

The objective of this study was to develop, analyze composition and evaluate the microbiological and sensory characteristics of high-protein diet bars (PB) with the addition of chia grain (Salvia hispanica L.), partially replacing isolated soy protein and concentrated whey protein, in proportions of 0, 10, 15 and 20%. The proximate composition was analyzed of PB, for microbiological quality of Bacillus cereus, Filamentous fungi and yeast count, total fecal coliforms, and Salmonella ssp. search. Sensory analysis was performed utilizing acceptance testing of characteristics on a nine-point hedonic scale for various attributes, including purchasing intention of the tested PB. Bars showed 20% moisture, 2.3% ash, 20-23% protein and 19% lipids. The effect of increasing of chia was to increase crude fiber content and decrease total carbohydrate and total energy value. All samples were within the microbiological food standards established by current legislation. All PB formulations obtained a good overall impression index and all characteristics were above mean grades, with the exception of taste (63%) in the PB containing 0% chia. Chia grain has a positive influence on sensory aspects and appears to be an alternative way to increase the nutritional quality of high-protein diet bars

Presence of multiple bacterial markers in clinical samples might be useful for presumptive diagnosis of infection in cirrhotic patients with culture-negative reports

Bacterial infections in cirrhotic patients with ascites are associated with a severe prognosis and an increased risk of death. The microbiological standard tests for the diagnosis of suspected infection, based on culture test of blood and ascitic fluid, are, in many cases (30-40 %), negative, even when patients show symptoms of infection. A multiple culture-independent protocol was applied and evaluated as a diagnostic and prognostic tool for the detection of bacterial infection in cirrhotic patients. Sixty-four culture-negative samples obtained from 34 cirrhotic patients, with PMN < 250 cells/μl of ascitic fluid, were screened for the presence of bacterial DNA, endotoxin, peptidoglycan/β-glucan and microscopically visible bacterial cells. Correlations between the presence of multiple markers and various clinical and laboratory parameters were evaluated. Bacterial DNA was detected in 23 samples collected from 16 patients; a large part of these samples also showed the presence of other bacterial markers, which was associated with a worsening of liver functionality, a higher incidence of infections during the follow-up and a higher mortality rate in our cohort of cirrhotic patients. We believe that the detection of additional bacterial markers in bacterial DNA-positive clinical samples makes the bacterial presence and its clinical significance more realistic and might be useful as early markers of an ongoing bacterial infection and in establishing a clinical prognosis

Pathogenic Yersinia and Listeria monocytogenes in organic pork production

The goal of this study is to determine the prevalence of pathogenic Yersinia and Listeria monocytogenes in organic pork production and assess risks in different steps of the pork production chain

Organic residues - a resource for arable soils

An increased recirculation of urban organic residues to arable soils has several environmental benefits, but there is a need for reliable test systems to ensure that soil quality is maintained. In this thesis, soil microbial, chemical and physical properties were included in an integrated evaluation to reflect the positive and negative effects of amending arable soils with organic residues. Efficient statistical tools and methods to describe intrinsic spatial variation are important when evaluating soil data. A new method was developed, combining near infrared reflectance (NIR) spectroscopy with principal component analysis (PCA). The first principal component (PC1) of NIR data described spatial soil variation better than the conventional soil variables total carbon, clay content and pH. A long-term field trial was established in which the soil was amended annually with organic residues (compost, biogas residues, sewage sludge) and fertilizers (pig manure, cow manure and mineral fertilizer, NPS). Annual measurements of soil and crop quality as well as yield revealed that biogas residues performed best among the organic residues. It improved several important microbiological properties, such as substrate-induced respiration (SIR) and potential ammonium oxidation (PAO), and it compared well with mineral fertilizer in terms of grain quality and harvest yield. Altogether, the results from the field trial showed no negative effects from any of the organic residues. Short- and moderately long-term effects of wood ash and compost on potential denitrification activity (PDA) and PAO were evaluated in a laboratory incubation experiment. Wood ash application had a profound toxic effect on PDA both in the short- and long-term. This toxic effect was mitigated when compost was added to the soil

Complex of Chemical-technological and Sanitary-hygienic Quality Indicators of the New Pastry Products of Special Nutrition

The complex of chemical-technological and sanitary-hygienic quality indicators of new pastry products of special nutrition was studied. The original recipes of meat pastries for special nutrition, enriched with biologically active components at the expanse of vitaminized blended vegetable oils (VBVO) and protein-fatty emulsions (PFE) on their base, were elaborated. There were elaborated four recipes of pastries of chicken and Turkey with PFE, included in recipes in the amount 15…20 % and with vitaminized blended vegetable oils of two-component and three-component composition in the amount 10 %. Pastry samples, prepared according to SSTC 4432:2005 were used as a control.VBVO composition and fat-soluble vitamins content in them was determined by the gasochromatographic method.Molecular-genetic methods were used for the accelerated diagnostics of pastries safety by agents of food intoxications– Clostridium perfringens and Bacillus cereus, number of mesophyl aerobic and facultative-anaerobic microorganisms (NMAFAnM), classic ones – colon bacillus group bacteria (CBGB), sulphite reductive clostridia, Staphylococcus aureus, L.monocytogenes, Salmonella. The storage term of products was prolonged in 2 times (48 against 24 hours) according to SSTC). The expedience of their introduction in production was proved