scholarly journals Microcalorimetry—Versatile Method of Describing Bacterial Growth

2021 ◽  
Vol 11 (20) ◽  
pp. 9740
Author(s):  
Mihnea Ioan Gabriel Popa ◽  
Adrian Cursaru ◽  
Bogdan Serban ◽  
Bogdan Cretu ◽  
Andrei Alexandru Muntean ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Growth Curves ◽  
Time Interval ◽  
Bacterial Identification ◽  
Industrialized Countries ◽  
Postoperative Infections ◽  
Bacterial Colony ◽  
Artificial Joints ◽  
Thermal Signal ◽  
Alternative Means

(1) Background: Due to the aging population in industrialized countries and due to the increase in the number of traffic or sports accidents, the number of artificial joints and implants for osteosynthesis will increase in the coming years. Therefore, the risk of postoperative infections will be higher as well. (2) Methods: For this study, we combined classical bacterial identification with the description of bacterial growth curves using microcalorimetry. (3) Results: We evaluated the growth of S. aureus and S. epedermidis, but we believe that this can be applied to any anaerobic or aerobic bacterial colony. We discovered that the time interval after which we can identify a growth curve does not exceed 15–20 h. (4) Conclusions: The diagnosis made by combining the methods of sonication and microcalorimetry manages to provide a great deal of information about the bacteria we studied. Microcalorimetry has real potential as a method for obtaining quick diagnosis in various cases of infection, but many more experiments need to be done to ensure the correct use of this technique. A detailed investigation (including kinetic analysis) of the reproducible thermal signal of bacterial growth can lead to the development of alternative means of rapid bacterial identification.

scholarly journals Effect of erythritol and xylitol on Streptococcus pyogenes causing peritonsillar abscesses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Siiri Kõljalg ◽  
Risto Vaikjärv ◽  
Imbi Smidt ◽  
Tiiu Rööp ◽  
Anirikh Chakrabarti ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Bacterial Growth ◽  
Growth Curves ◽  
Culture Collection ◽  
Exponential Phase ◽  
Clinical Isolates ◽  
Growth Inhibitors ◽  
Throat Culture ◽  
Potent Growth

AbstractPolyols are effective against caries-causing streptococci but the effect on oropharynx-derived pyogenic streptococci is not well characterised. We aimed to study the effect of erythritol (ERY) and xylitol (XYL) against Streptococcus pyogenes isolated from peritonsillar abscesses (PTA). We used 31 clinical isolates and 5 throat culture collection strains. Inhibition of bacterial growth by polyols at 2.5%, 5% and 10% concentrations was studied and the results were scored. Amylase levels in PTA pus were compared to polyol effectivity scores (PES). Growth curves of four S. pyogenes isolates were analysed. Our study showed that XYL was more effective than ERY inhibiting 71–97% and 48–84% of isolates, respectively, depending of concentrations. 48% of clinical and all throat strains were inhibited by polyols in all concentrations (PES 3). PES was negative or zero in 26% of the isolates in the presence of ERY and in 19% of XYL. ERY enhanced the growth of S. pyogenes isolated from pus with high amylase levels. Polyols in all concentrations inhibited the growth in exponential phase. In conclusion, ERY and XYL are potent growth inhibitors of S. pyogenes isolated from PTA. Therefore, ERY and XYL may have potential in preventing PTA in the patients with frequent tonsillitis episodes.

Decomposition of Growth Curves into Growth Rate and Acceleration: a Novel Procedure to Monitor Bacterial Growth and the Time-Dependent Effect of Antimicrobials

2021 ◽  
Author(s):  
M. Luisa Navarro-Pérez ◽  
M. Coronada Fernández-Calderón ◽  
Virginia Vadillo-Rodríguez
Keyword(s):  
Growth Rate ◽  
Mathematical Models ◽  
Bacterial Growth ◽  
Time Course ◽  
Antimicrobial Agents ◽  
Numerical Procedure ◽  
Growth Curves ◽  
Predictive Microbiology ◽  
Insight Into ◽  
Over Time

In this paper, a simple numerical procedure is presented to monitor the growth of Streptococcus sanguinis over time in the absence and presence of propolis, a natural antimicrobial. In particular, it is shown that the real-time decomposition of growth curves obtained through optical density measurements into growth rate and acceleration can be a powerful tool to precisely assess a large range of key parameters [ i.e. lag time ( t 0 ), starting growth rate ( γ 0 ), initial acceleration of the growth ( a 0 ), maximum growth rate ( γ max ), maximum acceleration ( a max ) and deceleration ( a min ) of the growth and the total number of cells at the beginning of the saturation phase ( N s )] that can be readily used to fully describe growth over time. Consequently, the procedure presented provides precise data of the time course of the different growth phases and features, which is expected to be relevant, for instance, to thoroughly evaluate the effect of new antimicrobial agents. It further provides insight into predictive microbiology, likely having important implications to assumptions adopted in mathematical models to predict the progress of bacterial growth. Importance: The new and simple numerical procedure presented in this paper to analyze bacterial growth will possibly allow identifying true differences in efficacy among antimicrobial drugs for their applications in human health, food security, and environment, among others. It further provides insight into predictive microbiology, likely helping in the development of proper mathematical models to predict the course of bacterial growth under diverse circumstances.

scholarly journals Impact of diet on the immunological microenvironment of the pregnant uterus and its relationship to allergic disease in the offspring: a review of the recent literature

2006 ◽  
Vol 124 (5) ◽  
pp. 298-303 ◽  
Author(s):  
Daniella Campelo Batalha Cox Moore ◽  
Pedro Xavier Elsas ◽  
Elisabeth Santos Maximiano ◽  
Maria Ignez Capella Gaspar Elsas
Keyword(s):  
Allergic Disease ◽  
Allergic Diseases ◽  
Perinatal Period ◽  
Time Interval ◽  
Industrialized Countries ◽  
Pregnant Uterus ◽  
Medical Progress ◽  
Immunological Profile ◽  
Dietary Content ◽  
The Relationship

Medical progress has reduced the mortality from infectious diseases in most countries, but allergic diseases have become more prevalent worldwide over the same period, especially in industrialized countries. This has prompted speculation that modern lifestyles have altered the relationship between heredity and environment so as to promote development of an atopic phenotype when exposure to infection decreases. A healthy uterine microenvironment is known to favor Th2 lymphocyte development. However, some evidence suggests that persistence of the Th2 pattern of immunity directs the developing organism's immune response towards a long-lasting atopic phenotype. Even though the outcome also depends on other factors (such as infection, functional state of the intestinal microflora, and exposure to environmental allergens at times critical to development), it seems that the immune system during the perinatal period is responsive to interventions that are no longer effective in adulthood. We have reviewed the literature accessible through Medline to identify recent advances in the prevention of allergic disease through interventions in the fetal-maternal relationship. Diet seems to have a significant impact on the immunological profile of the pregnant uterus, as well as on the postnatal development of allergic disease in the offspring, as suggested by the effects of probiotic bacteria and by manipulations of the dietary content of polyunsaturated fatty acids and antioxidants. This highlights the need for further studies, in order to define the best intervention methods, the most appropriate time interval and the individuals who will most likely benefit from them.

Notes on reparameterization of bacterial growth curves

1992 ◽  
Vol 9 (2) ◽  
pp. 169-171 ◽  
Author(s):  
József Baranyi
Keyword(s):  
Bacterial Growth ◽  
Growth Curves

scholarly journals Chitinase Activity of Serratia marcescens PT-6 Cultured in Bioreactor with Various Aeration Rate

2020 ◽  
Vol 147 ◽  
pp. 03010
Author(s):  
Niswah Umhudloh Dzakiyya ◽  
Indun Dewi Puspita ◽  
Sri Pudjiraharti
Keyword(s):  
Serratia Marcescens ◽  
Bacterial Growth ◽  
Colorimetric Assay ◽  
Chitinase Activity ◽  
Aeration Rate ◽  
Agitation Speed ◽  
Bacterial Colony ◽  
Shrimp Shell ◽  
Shrimp Shell Waste ◽  
Chitinase Production

Chitin is a biopolymer composed of N-acetylglucosamine (NAG) monomers. Bacterial chitinase helps in bioconversion process of chitin from shrimp shell waste into NAG. This study aimed to determine the effect of aeration on chitinase activity, NAG concentration in medium, bacterial growth, and pH medium; to determine the optimum aeration on chitinase production of Serratia marcescens PT-6. Chitinase was produced using a 1.5 L bioreactor at pH 7, 30°C, 200 rpm agitation speed, and variation of aeration rates (0.4, 0.6 and 0.8 vvm). Parameters examined included pH, bacterial growth (log CFU/ml), chitinase activity (U/ml), and NAG concentration in medium (µg/ml). Bacterial growth was measured by enumeration of bacterial colony in medium, while chitinase activity and NAG concentration were analyzed by colorimetric assay. Parameters was measured every 8 hours during 60 hours of incubation. Aeration rate showed a significant effect (P≤0.05) on chitinase activity and NAG concentration, but not significant (P≥0.05) on bacterial growth and pH medium. Optimum aeration rate on producing chitinase was 0.6 vvm with the highest chitinase activity of 0.0125 U/ml at 40 hours incubation. This study implies that optimization of bioreactor condition improved the production of chitinase by S. marcescens PT-6.

Bacterial Normalized Binary Fission Growth Model

2021 ◽  
Author(s):  
John P Keady
Keyword(s):  
Growth Model ◽  
Bacterial Growth ◽  
Bacterial Population ◽  
Size Range ◽  
Control Sample ◽  
Growth Curves ◽  
Growth Cycle ◽  
Binary Fission ◽  
Bacterial Proliferation

Mathematical models have traditionally been used to facilitate the interpretation of bacterial growth curves in order to more accurately understand and identify variations in bacterial proliferation. Here, a binary fission growth model was developed to normalize starting bacterial levels, allowing for the identification of changes in bacterial growth and the separation of a bacterial population as it correlates to size. This normalized binary fission model (NBF) relies on a multi-bin growth mode, where each bin is associated with a size range during a growth cycle. The proposed NBF model allows for a determination of the percentage of treated bacteria eradicated compared to a control sample, either generally across all bacterial binary fission sizes or specific to a size range or bin. Comparisons between the NBF model and experimental observations demonstrates that bacterial growth curves, and the ratio of sample growth to a control, can be used to both determine and normalize initial variations in bacterial size, and quantity, among test samples, as well as identify final nutrient levels and the percentage of bacteria affected by treatment.

More than simply microbial growth curves

2016 ◽  
Vol 1 (2) ◽  
pp. 63 ◽  
Author(s):  
Ji-Dong Gu
Keyword(s):  
Bacterial Growth ◽  
Microbial Growth ◽  
Growth Curves ◽  
Lag Phase ◽  
Growth Data ◽  
Phase Growth ◽  
Simple Task ◽  
Wide Range ◽  
Comparative Results ◽  
Comparative Information

Bacterial growth is a very important piece of information in a wide range of investigation and, in most of the time the data are simply shown directly without any further processing. In a single factor investigation without comparative information to be extracted, this simple approach can be used together with other data to form a comprehensive set of results. When comparison is involved, such direct showing of bacterial growth curves without processing cannot warrant a meaningful comparison thoroughly and further processing of data is necessary. In addition, there is little, if any, quantitative data for the comparison from the display of growth curves and description of a number of curves is not a simple task, especially in a meaningful way for assimilation of the data to readers. With this in mind, I would like to remind of those who plan to show such data as growth curves for their potential publication to carry this further to generate comparative results for a much meaningful interpretation by modeling and calculation from the raw growth data over time of incubation. By calculating with existing equations, the lag phase, growth rate and the biomass can be derived from a series of growth curves for a more effective and meaningful analysis. This approach is not new, but remembrance of such available tool is more important so that research data are shown professionally and also scientifically for meaning presentation and effective assimilation.

Biosocial advantages of an adequate birth interval

1977 ◽  
Vol 9 (S4) ◽  
pp. 69-81 ◽  
Author(s):  
David Morley
Keyword(s):  
Health Worker ◽  
Birth Interval ◽  
Intellectual Development ◽  
Considerable Effect ◽  
Good Evidence ◽  
Time Interval ◽  
Industrialized Countries ◽  
Part Time ◽  
The Third World ◽  
Health Programmes

SummaryThe process of urbanization in the Third World has vastly outstripped the equivalent change in industrialized countries, and also far exceeds the population growth. This urbanization has been associated with the spread of artificial feeding and associated short birth intervals. Although relatively few studies have been undertaken on the effect of length of birth interval, we have good evidence that it is associated with poorer growth, a less satisfactory intellectual development, and a higher mortality. Child health programmes have, up to the present, been only marginally involved in the question of birth interval, although as mentioned this has a considerable effect on the health of the child. In overcoming malnutrition, simple weight charts are now widely accepted as a useful tool by which the adequate growth of the child can be monitored, and in this way malnutrition prevented. These same weight charts can be a useful means of identifying in any community the month in which a woman has a 5% chance of conceiving again. The charts can also be used as a means of recording the dialogue between the health worker and the parents on the most appropriate time interval to separate their children. However, to achieve this the developing countries will need a vast increase in the health personnel they have available. Experience now in a number of countries suggests that the part-time health worker may be particularly appropriate for providing such services.

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