DETECTION AND DIFFERENTIATION OF SPORE AND VEGETATIVE FORMS OF BACILLUS SPP. USING INFRARED SPECTROSCOPIC METHODS

2008 ◽  
Vol 18 (02) ◽  
pp. 417-427
Author(s):  
DIANE ST. AMANT ◽  
MARK CAMPBELL ◽  
ANDREW BECK ◽  
LESLIE WILLIAMS ◽  
JENNIFER MINTER ◽  
...  
Keyword(s):  
Thin Film ◽  
Infrared Spectroscopy ◽  
Attenuated Total Reflection ◽  
Bacillus Species ◽  
Infrared Spectrometry ◽  
Limited Information ◽  
Transmission Method ◽  
Vegetative Cells ◽  
Bacillus Spp ◽  
Bacillus Spores

Infrared spectroscopy has been demonstrated as a powerful tool for taxonomic classification of bacteria when the microbes are grown and sampled under carefully controlled conditions. Infrared spectroscopy affords limited information about relative proportions of certain chemical functional groups in whole microbial cells. The objective of this work is to elucidate the ability of infrared spectroscopy to identify and speciate Bacillus spp. regardless of sample history. Spectrometers utilize different scanning methods to collect infrared absorption spectra. We employed three; transmission through a thin film, transmission infrared microscopy, and Attenuated Total Reflection (ATR). Target organisms include Bacillus anthracis, and several near neighbors. Each strain was cultured at 24°C and 35°C on three solid media. Microorganisms were incubated for up to ten days to include vegetative cells, spore formation and mature spores. Triplicate microbe samples were prepared and analyzed according to instrument requirements using the three measurement modes. Triplicate samples of BSL-3 organisms were analyzed only by the thin film transmission method. Spectral data was analyzed using the cluster analysis function of OPUS software. We report that infrared spectrometry is capable of discerning Bacillus spores from vegetative cells and the phylogenic clustering of Bacillus species according to pathogenicity levels via infrared spectral analysis.

Three Clusters of Bacillus Pseudobacteremia Related to a Radiometric Blood Culture Analyzer

1984 ◽  
Vol 5 (2) ◽  
pp. 71-74 ◽  
Author(s):  
Inge Gurevich ◽  
Patricia Tafuro ◽  
Sharon P. Krystofiak ◽  
Robert D. Kalter ◽  
Burke A. Cunha
Keyword(s):  
Blood Culture ◽  
Clinical Signs ◽  
Blood Cultures ◽  
Bacillus Species ◽  
Common Source ◽  
Air Conditioner ◽  
Close Proximity ◽  
Bacillus Spp ◽  
Multiple Blood ◽  
Bacillus Spores

AbstractDuring a ten-month period from September 1981 to July 1982 three episodes of pseudobacteremia due to Bacillus species occurred at this 550-bed institution. The first involved eight isolates, the second 11, and the third seven isolates of the organism, all with the same antibiogram.The patients involved did not exhibit clinical signs of septicemia, and in only one case was more than one specimen per patient positive when multiple blood samples were obtained. Occasional blood cultures of Bacillus species identified in between clusters revealed a different antibiogram.Extensive epidemiologic investigation of patient locations, phlebotomists, and time of cultures yielded no common source. Components involved in the transport and processing of blood cultures, including the radiometric blood culture processor, were also sampled but without recovery of the organism. After the last episode, a layer of dust was noted inside the machine, and culture of this dust grew Bacillus spp. with the same antibiogram as those found in the blood cultures. The filter from an air conditioning unit in close proximity to the machine grew several species of Bacillus.It is presumed that Bacillus spores in the dust were introduced into the blood culture bottles following the heat sterilization of the gas sampling (inoculation/removal) needles.Modification of the cover of the machine was undertaken to prevent access of dust bearing microbes to the inside of the machine. In addition, maintenance now includes regular disinfection/cleaning of the “floor” of the machine, and more frequent changes of the air conditioner filter.

Application of Nisin and Pediocin against Resistance and Germination of Bacillus Spores in Sous Vide Products

2009 ◽  
Vol 72 (3) ◽  
pp. 515-523 ◽  
Author(s):  
M. L. CABO ◽  
B. TORRES ◽  
J. J. R. HERRERA ◽  
M. BERNÁRDEZ ◽  
L. PASTORIZA
Keyword(s):  
Vegetative State ◽  
Bacillus Species ◽  
Processed Foods ◽  
Positive Interaction ◽  
Minimally Processed ◽  
Vegetative Cells ◽  
Additional Challenge ◽  
Bacillus Spores ◽  
Sous Vide ◽  
High Concentrations

Sous vide and other mild preservation techniques are increasingly demanded by consumers. However, spores often will survive in minimally processed foods, causing both spoilage and safety problems. The main objective of the present work was to solve an industrial spoilage problem associated with two sous vide products: mushrooms and shellfish salad. Bacillus subtilis and Bacillus licheniformis predominated as the most heat-resistant organisms isolated from mushrooms and shellfish salad, respectively. The combined effects of nisin and pediocin against resistance and germination of both Bacillus species were described by empirical equations. Whereas nisin was more effective for decreasing thermal resistance of B. subtilis spores, pediocin was more effective against B. licheniformis. However, a significant positive interaction between both biopeptides for decreasing the proportion of vegetative cells resulting from thermoresistant spores was demonstrated in later experiments, thus indicating the increased efficacy of applying high concentrations of both bacteriocins. This efficacy was further demonstrated in additional challenge studies carried out at 15°C in the two sous vide products: mushrooms and shellfish salad. Whereas no vegetative cells were detected after 90 days in the presence of bacteriocins, almost 100% of the population in nontreated samples of mushrooms and shellfish salad was in the vegetative state after 17 and 43 days of storage at 15°C, respectively.

Biofilm-Spore Response in Bacillus cereus and Bacillus subtilis during Nutrient Limitation

2006 ◽  
Vol 69 (5) ◽  
pp. 1168-1172 ◽  
Author(s):  
D. LINDSAY ◽  
V. S. BRÖZEL ◽  
A. VON HOLY
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Cereus ◽  
Growth Conditions ◽  
Bacillus Species ◽  
Practical Consideration ◽  
Limited Growth ◽  
Vegetative Cells ◽  
Bacillus Subtilis 168 ◽  
Standard Plate ◽  
Bacillus Spores

This study aimed to trace the dynamics of biofilm formation by vegetative cells and endospores of Bacillus cereus DL5 and Bacillus subtilis 168. Counts of B. cereus DL5 and B. subtilis 168 vegetative cells and spores either attached to glass wool or, correspondingly, planktonic cells were determined by standard plate-counting methods. Results from this study highlighted the biofilm-forming potential of both spores and vegetative cells of two different Bacillus species. It was shown that once Bacillus spores had attached to a surface, the spores germinated under favorable (B. cereus DL5) and even unfavorable (B. subtilis 168) nutrient conditions, resulting in biofilms containing both spores and vegetative populations. Furthermore, it was suggested that vegetative B. cereus DL5 cells exhibited a low propensity for spore formation in attached and planktonic growth forms in nutrient-limited growth medium. By contrast, vegetative B. subtilis 168 cells readily formed spores in planktonic and attached microcosms when exposed to nutrient-limited growth conditions. Sporulation in attached Bacillus populations is an important practical consideration for many food industries, such as dairy processing, where bacilli are routinely isolated from populations attached to processing-equipment surfaces.

scholarly journals Optimized, One-Step, Recovery-Enrichment Broth for Enhanced Detection of Listeria monocytogenes in Pasteurized Milk and Hot Dogs

2002 ◽  
Vol 85 (2) ◽  
pp. 501-504 ◽  
Author(s):  
Stephen J Knabel
Keyword(s):  
Listeria Monocytogenes ◽  
False Negative ◽  
Molecular Methods ◽  
Vegetative Cells ◽  
Enrichment Broth ◽  
Penn State ◽  
Bacillus Spp ◽  
One Step ◽  
Bacillus Spores ◽  
Low Levels

Abstract A one-step, recovery-enrichment broth, optimized Penn State University (oPSU) broth, was developed to consistently detect low levels of injured and uninjured Listeria monocytogenes cells in ready-to-eat foods. The oPSU broth contains special selective agents that inhibit growth of background flora without inhibiting recovery of injured Listeria cells. After recovery in the anaerobic section of oPSU broth, Listeria cells migrated to the surface, forming a black zone. This migration separated viable from nonviable cells and the food matrix, thereby reducing inhibitors that prevent detection by molecular methods. The high Listeria-to-background ratio in the black zone resulted in consistent detection of low levels of L. monocytogenes in pasteurized foods by both cultural and molecular methods, and greatly reduced both false-negative and false-positive results. oPSU broth does not require transfer to a secondary enrichment broth, making it less laborious and less subject to external contamination than 2-step enrichment protocols. Addition of 150mM d-serine prevented germination of Bacillus spores, but not the growth of vegetative cells. Replacement of d-serine with 12 mg/L acriflavin inhibited growth of vegetative cells of Bacillus spp. without inhibiting recovery of injured Listeria cells. oPSU broth may allow consistent detection of low levels of injured and uninjured cells of L. monocytogenes in pasteurized foods containing various background microflora.

scholarly journals Quantification and Classification of Diclofenac Sodium Content in Dispersed Commercially Available Tablets by Attenuated Total Reflection Infrared Spectroscopy and Multivariate Data Analysis

2021 ◽  
Vol 14 (5) ◽  
pp. 440
Author(s):  
Eirini Siozou ◽  
Vasilios Sakkas ◽  
Nikolaos Kourkoumelis
Keyword(s):  
Infrared Spectroscopy ◽  
Low Cost ◽  
Diclofenac Sodium ◽  
Reference Method ◽  
Sodium Content ◽  
Attenuated Total Reflection ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
Ft Ir

A new methodology, based on Fourier transform infrared spectroscopy equipped with an attenuated total reflectance accessory (ATR FT-IR), was developed for the determination of diclofenac sodium (DS) in dispersed commercially available tablets using chemometric tools such as partial least squares (PLS) coupled with discriminant analysis (PLS-DA). The results of PLS-DA depicted a perfect classification of the tablets into three different groups based on their DS concentrations, while the developed model with PLS had a sufficiently low root mean square error (RMSE) for the prediction of the samples’ concentration (~5%) and therefore can be practically used for any tablet with an unknown concentration of DS. Comparison with ultraviolet/visible (UV/Vis) spectrophotometry as the reference method revealed no significant difference between the two methods. The proposed methodology exhibited satisfactory results in terms of both accuracy and precision while being rapid, simple and of low cost.

scholarly journals Biodegradable Polymeric Foams Based on Modified Castor Oil, Styrene, and Isobornyl Methacrylate

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1872
Author(s):  
James Anthony Dicks ◽  
Chris Woolard
Keyword(s):  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Attenuated Total Reflection ◽  
Infrared Spectrometry ◽  
Cell Diameter ◽  
Polymeric Foams ◽  
Reactive Diluent ◽  
Structure Property ◽  
Aerobic Soil

The environmental issues of petroleum-derived polymeric foams have necessitated seeking renewable alternatives. This work aims to prepare renewable free-radically polymerized polymeric foams with the ability to biodegrade. Furthermore, this work attempted to incorporate a bio-based reactive diluent, which has not been reported in the literature. The synthesis of maleated castor oil glycerides was performed with products analyzed by Fourier transform infrared spectrometry using attenuated total reflection (ATR-FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. Polymeric foams were prepared using maleated castor oil glycerides via free radical copolymerization with styrene and isobornyl methacrylate as reactive diluents. Scanning electron microscopy (SEM) was used to determine anisotropic macrocellular morphology, with log-normal cell diameter distributions. The compressive mechanical and energy absorption properties were investigated; the polymeric foams displayed Young’s modulus up to 26.85 ± 1.07 MPa and strength up to 1.11 ± 0.021 MPa using styrene as the reactive diluent, and Young’s modulus up to 1.38 ± 0.055 MPa and strength up to 0.088 MPa when incorporating isobornyl methacrylate. Furthermore, a thorough analysis of the cellular structure–property relationships was performed, indicating relationships to cell diameter, cell wall thickness and apparent density. The polymeric foams displayed rapid mass loss in an aerobic soil environment with multiple erosion sites revealed by SEM. In conclusion, renewable polymeric foams with excellent compressive properties were achieved using styrene as reactive diluent, but the incorporation of isobornyl methacrylate decreased strength-related properties.

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