Bacterial growth kinetics: modelling and evaluation of two-compartment radioassay

1989 ◽  
Vol 35 (9) ◽  
pp. 874-880
Author(s):  
Vipa Boonkitticharoen ◽  
James C. Ehrhardt ◽  
Peter T. Kirchner
Keyword(s):  
Rate Constant ◽  
Bacterial Growth ◽  
Growth Models ◽  
Growth Curves ◽  
Exponential Model ◽  
Generation Rate ◽  
Kinetics Modelling ◽  
Quantitative Measurements ◽  
Relative Standard ◽  
Radioactive Measurement

Quantitative measurements of bacterial growth may be made using a radioassay technique. This method measures, by scintillation counting, the 14CO2 derived from die bacterial metabolism of a 14C-labeled substrate. Mathematical growth models may serve as reliable tools for estimation of the generation rate constant (or slope of the growth curve) and provide a basis for evaluating assay performance. Two models, i.e., exponential and logistic, are proposed. Both models yielded an accurate fit to the data from radioactive measurement of bacterial growth. The exponential model yielded high precision values of the generation rate constant, with an average relative standard deviation of 1.2%. Under most conditions the assay demonstrated no changes in the slopes of growth curves when the number of bacteria per inoculation was changed. However, the radiometric assay by scintillation method had a growth-inhibiting effect on a few strains of bacteria. The source of this problem was thought to be hypersensitivity to trace amounts of toluene remaining on the detector.Key words: bacterial growth modelling.

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.

scholarly journals Age and growth of franciscana dolphins, Pontoporia blainvillei (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

2010 ◽  
Vol 90 (8) ◽  
pp. 1493-1500 ◽  
Author(s):  
Silvina Botta ◽  
Eduardo R. Secchi ◽  
Mônica M.C. Muelbert ◽  
Daniel Danilewicz ◽  
Maria Fernanda Negri ◽  
...  
Keyword(s):  
Growth Models ◽  
Growth Curves ◽  
Small Sample ◽  
Age And Growth ◽  
Buenos Aires Province ◽  
Von Bertalanffy ◽  
Southern Brazil ◽  
Data Set ◽  
Males And Females ◽  
Pontoporia Blainvillei

Age and length data of 291 franciscana dolphins (Pontoporia blainvillei) incidentally captured on the coast of Rio Grande do Sul State (RS), southern Brazil, were used to fit growth curves using Gompertz and Von Bertalanffy growth models. A small sample of franciscanas (N = 35) from Buenos Aires Province (BA), Argentina, were used to see if there are apparent growth differences between the populations. Male and female franciscana samples from both areas were primarily (78–85%) <4 years of age. The Von Bertalanffy growth model with a data set that excluded animals <1 year of age provided the best fit to data. Based on this model, dolphins from the RS population reached asymptotic length at 136.0 cm and 158.4 cm, for males and females, respectively. No remarkable differences were observed in the growth trajectories of males and females between the RS and BA populations.

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 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 On the use of growth models for forecasting epidemic outbreaks with application to COVID-19 data

2020 ◽  
Author(s):  
Chenangnon F. TOVISSODE ◽  
Bruno E. LOKONON ◽  
Romain GLELE KAKAÏ
Keyword(s):  
Growth Model ◽  
Growth Models ◽  
Exponential Model ◽  
Limited Data ◽  
Model Framework ◽  
Phase Dynamics ◽  
Epidemic Dynamics ◽  
Isolation Measure ◽  
Containment Measures ◽  
Model Curve

The initial phase dynamics of an epidemic without containment measures is commonly well modeled using exponential growth models. However, in the presence of containment measures, the exponential model becomes less appropriate. Under the implementation of an isolation measure for detected infectives, we propose to model epidemic dynamics by fitting a flexible growth model curve to reported positive cases and to infer the overall epidemic dynamics by introducing information on the detection/testing effort and recovery and death rates. The resulting modeling approach is close to the SIQR (Susceptible- Infectious-Quarantined-Recovered) model framework. We focused on predicting the peaks (time and size) in positive cases, actives cases and new infections. We applied the approach to data from the COVID-19 outbreak in Italy. Fits on limited data before the observed peaks illustrate the ability of the flexible growth model to approach the estimates from the whole data.

Comparing growth and maturity of sympatric Atlantic (Gadus morhua) and Greenland (Gadus ogac) cod in coastal Newfoundland

2013 ◽  
Vol 91 (9) ◽  
pp. 672-677 ◽  
Author(s):  
D.C. Knickle ◽  
G.A. Rose
Keyword(s):  
Gadus Morhua ◽  
Resource Competition ◽  
Growth Models ◽  
Growth Curves ◽  
Von Bertalanffy ◽  
Allometric Growth ◽  
Species Being ◽  
Trinity Bay

Growth and maturity of two sympatric gadids were examined from 48 Atlantic (Gadus morhua L., 1758) and 42 Greenland (Gadus ogac Richardson, 1836) cod ranging from 17 to 74 cm in length collected from an inshore area of Trinity Bay, Newfoundland, Canada, during 2009 and 2010. Ages estimated from otolith readings ranged from 2 to 7 for both species. Age and size at 50% maturity differed between species, being 2.3 years and 28.2 cm for G. ogac and 4.6 years and 48.8 cm for G. morhua. von Bertalanffy growth models did not differ between species with parameters L∞ = 91 cm, k = 0.16 year−1, t0 = –0.02 years for G. ogac and L∞ = 112 cm, k = 0.13 year−1, t0 = 0.18 years for G. morhua. Length (L) – mass (W) relationships differed; W = 0.000005 kg·cm−b × L3.17 for G. ogac and W = 0.000011 kg·cm−b × L2.91 for G. morhua suggested slightly positive and negative allometric growth, respectively. For G. morhua, growth curves, length–mass relationships, and maturity rates did not differ between fish collected during this and earlier studies. Differences in maturity schedules and growth may decrease resource competition and help facilitate coexistence of these species.

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 The Standard Deviation Structure as a New Approach to Growth Analysis in Weight and Length Data of Farmed Lutjanus guttatus

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 60
Author(s):  
Sergio G. Castillo-Vargasmachuca ◽  
Eugenio Alberto Aragón-Noriega ◽  
Guillermo Rodríguez-Domínguez ◽  
Leonardo Martínez-Cárdenas ◽  
Eulalio Arámbul-Muñoz ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Growth Parameters ◽  
Growth Models ◽  
Growth Curves ◽  
Gompertz Model ◽  
Information Criterion ◽  
Weight Growth ◽  
Length Data ◽  
Size At Age ◽  
The Right

In the present study, size-at-age data (length and weight) of marine cage-reared spotted rose snapper Lutjanus guttatus were analyzed under four different variance assumptions (observed, constant, depensatory, and compensatory variances) to analyze the robustness of selecting the right standard deviation structure to parametrize the von Bertalanffy, Logistic, and Gompertz models. The selection of the best model and variance criteria was obtained based on the Bayesian information criterion (BIC). According to the BIC results, the observed variance in the present study was the best way to parametrize the three abovementioned growth models, and the Gompertz model best represented the length and weight growth curves. Based on these results, using the observed error structure to calculate the growth parameters in multi-model inference analyses is recommended.

Sign in / Sign up

Export Citation Format

Share Document