Concentration Of Microorganisms Research Articles

Evaluation of a peracetic-acid-based sink drain disinfectant on the intensive care unit of a tertiary care centre in Belgium

Sink drains in hospitals are notorious reservoirs of bacteria, hosting both planktonic micro-organisms and biofilms within the siphon. Disinfectants based on peracetic acid are both non-corrosive and effective in eliminating biofilm and planktonic micro-organisms, presenting a potential solution for decontaminating sink drains. To examine the effectiveness of Clinell Drain Disinfectant, a peracetic-acid-based disinfectant, in the intensive care unit (ICU) of UZ Brussel. All 10 sinks in one of the ICU subunits known to be heavily contaminated were treated with Clinell Drain Disinfectant for one month. Throughout the treatment period, bacterial growth in the P-traps was systematically monitored qualitatively (using eSwab) and quantitatively (employing a sterile catheter and syringe) on various selective agar plates, processed and incubated in the WASPLab system. Matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy was used to identify all morphologically distinct colonies. At baseline, most of the sink drains were colonized by high concentrations of multidrug-resistant micro-organisms, primarily VIM-producing P.aeruginosa. The cultures taken immediately after decontamination yielded negative results, with only a very few exceptions. Nonetheless, it was observed that the biofilm in the upper section of the drain system remained unaffected, and within two days it was capable of recolonizing the liquid in the P-traps at a concentration >100,000cfu/mL. After one month, this disinfecting protocol did not result in a lasting decontamination of the sink drains. This study demonstrated the disinfectant's efficacy in decontaminating the P-trap liquid.

Thermally radiative nanofluid heat transfer analysis inside a closed chamber with gyrotactic microorganisms

PurposeThis paper aims to numerically examine the impact of gyrotactic microorganisms and radiation on heat transport features of magnetic nanoliquid within a closed cavity. Thermophoresis, chemical reaction and Brownian motion are also considered in flow geometry for the moment of nanoparticles.Design/methodology/approachFinite element method (FEM) was depleted to numerically approximate the temperature, momentum, concentration and microorganisms concentration of the nanoliquid. The present simulation was unsteady state, and the resulting transformed equations are simulated by FEM-based Mathematica algorithm.FindingsIt has been found that isotherm patterns get larger with increasing values of the magnetic field parameter. Additionally, numerical codes for rate of heat transport impedance inside the cavity with an increasing Brownian motion parameter values.Originality/valueTo the best of the authors’ knowledge, the research work carried out in this paper is new, and no part is copied from others’ works.

Oral Microbiocenosis in Cases of Inflammatory Periodontal Diseases in Children with Tuberculosis

Objective — to examine the microbial spectrum of the oral cavity in cases of inflammatory periodontal diseases of children with tuberculosis. Materials and methods. A study of the microbial habitat of oral biotopes and gingival surfaces was conducted in 97 children aged 6 to 17 years with inflammatory periodontal diseases and tuberculosis (treatment group). The control group consisted of 20 practically healthy children of the same age. The periodontal diseases were diagnosed according to M.F. Danilevsky’s classification (2000). The study of oral microbiocenosis and gingival surfaces in the examined groups of children was performed in accordance with Order No. 234 of the Ministry of Health of Ukraine as of 2006. Results and discussion. Aerobic, facultative anaerobic, and anaerobic bacteria persisted in the oral fluid and on the gingival surfaces of children with tuberculosis and inflammatory periodontal diseases. The most frequent colonies of bacteria were Streptococcus, in particular S. mutans, S. salivarius, S. β-haemolyticus, Staphylococcus (S. aureus, S. epidermidis).The significant evidence of Neisseria (N. catarrhalis) and Corynebacterium (C. xerosis) was revealed in the oral cavity and gingival surfaces of the examined children. The microflora of children from the treatment group revealed mostly Lactobacillus genus. The microbial associations of the examined children consisted of Candida, E. coli fungi. Smear microscopy revealed viruses. S. aureus was higher in the children from the treatment group as compared to the healthy children. In addition, the concentration of microorganisms was higher on the gingival surface versus the oral fluid and was more evident in the children from the treatment group. Conclusions. The obtained spectrum of the oral microbial contamination in the children with tuberculosis and inflammatory periodontal diseases revealed the persisting associations of aerobic, facultative anaerobic, and anaerobic bacteria. The inflammatory periodontal diseases in tuberculosis-infected children were accompanied by the evident increase in the frequency and concentration of microorganisms increasing with the higher severity of the specific process.

Enhancing effect of conductive materials and rumen microorganisms on the anaerobic digestion performance of a real traditional Chinese medicine wastewater

This work evaluated the effect of different concentrations of conductive materials and rumen microorganisms on the anaerobic digestion (AD) performance of real traditional Chinese medicine (TCM) wastewater. The experiments first determined the optimal organic concentration of 0.25 L/L for the AD system and removed suspended solids from real TCM wastewater to reduce the inhibition effect on methanogenesis. Analysis of the modified Gompertz model showed that the addition of activated carbon, biochar, cow manure, and rumen fluid at doses of 12 g/L, 12 g/L, 12 mL/L, and 125 mL/L, respectively, had the greatest effect on CH4 production, increasing the cumulative CH4 yield by 13.5 %, 10.4 %, 26.8 %, and 32.9 %. Through microbial community and metabolism pathway analyses, the conductive materials promoted direct interspecies electron transfer (DIET) between Clostridium and Methanothrix, and the acetoclastic methanogenic pathway dominated by acetyl-CoA synthase. Rumen microorganisms enhanced AD performance by promoting the growth of hydrogenotrophic methanogens and the abundance of genes dominated by formylmethanofuran dehydrogenase in the hydrogenotrophic methanogenic pathway, illustrating the relationship between microbial community and metabolism pathway. Rumen microorganisms increased CH4 production more than conductive materials in real TCM wastewater. This study helps to better understand the internal mechanisms by which different materials enhance AD performance.

PSVII-25 The influence of trace mineral source on in vitro trace mineral solubility and trace mineral concentrations of rumen microorganisms in canulated steers fed a diet formulated for lactating dairy cows

PSVII-25 The influence of trace mineral source on in vitro trace mineral solubility and trace mineral concentrations of rumen microorganisms in canulated steers fed a diet formulated for lactating dairy cows

Reducing moisture content can promote the removal of pathogenic bacteria and viruses from sheep manure compost on the Qinghai-Tibet Plateau

Livestock manure contains a high concentration of pathogenic bacteria, viruses, and other harmful microorganisms. The effective elimination of these pathogens is of great significance to the harmless and resource utilization of livestock and poultry manure. Building upon prior research, this study further explored the removal efficiency of pathogenic bacteria and viruses in sheep manure compost on Qinghai-Tibet Plateau under 45 % (M45) and 60 % (M60) moisture content. The results showed that M45 led to a significant increase in the average composting temperature (P＜0.05), a notable reduction in the levels of Salmonella and Coliforms in the compost products, and facilitated the decline in abundance of various pathogens. As composting progressed, the abundance of viruses declined rapidly. Uroviricota was the most dominant viral phylum, and Siphoviridae, Myoviridae, Herpesviridae, and Podoviridae as the predominant viral families. M45 can significantly reduce the diversity and abundance of compost virus community (P＜0.05). The correlation analysis indicated a negative relationship between pathogens and the average temperature and humus content of the compost. In summary, the reduction of moisture content can enhance the biosafety of sheep manure compost products on the Qinghai-Tibet Plateau. These findings provide theoretical basis and technical support for the harmless and resource utilization of sheep manure waste on the Qinghai-Tibet Plateau.

Carreau nanofluid dynamics with activation energy gyrotactic microorganisms in a porous medium: Application to solar energy

This study investigates the magnetohydrodynamic (MHD) flow of Carreau nanofluid through a porous medium with motile microorganisms, focusing on various geometries under shear-thinning and shear-thickening conditions. The aim is to elucidate how factors such as activation energy, Schmidt number, Peclet number, bioconvection, Brownian motion, thermophoresis, and heat generation influence flow dynamics. Using similarity transformations, we nondimensionalize the governing equations and solve them numerically with the Runge–Kutta method and a shooting technique in MATLAB. Our findings indicate that variations in Carreau, magnetic, and suction parameters notably impact velocity, temperature, concentration, diffusion, wall friction, and heat transfer, generally resulting in reduced values. Specifically, the flat plate geometry exhibits lower skin friction, heat transfer, and mass transfer rates, as well as decreased gyrotactic microorganism effects. Increased activation energy enhances concentration fields, signaling slower chemical reactions, while higher Peclet numbers and bioconvection inversely affect flow properties. Additionally, reduced Schmidt numbers lead to lower microorganism concentrations. These results provide valuable insights into the complex interactions between fluid dynamics and microorganism behavior, with implications for optimizing processes in biotechnology and environmental management.

Water Disinfection Via Zinc Oxide (ZnO) Nanowires Chemically Fabricated on A Modified Polyurethane Substrate

Nowadays, water contamination is a big issue due to concerns about health and water scarcity. Unfortunately, most water for human consumption is contaminated with various pathogenic microorganisms that cause water-related diseases. Most traditional chemical and physical disinfectants are energy- and time-intensive and prone to generating harmful disinfection by-products. The recent controversy about waterborne diseases and the safety of commonly used disinfection methods has renewed interest in other forms of disinfection. Low-cost, high-efficiency, and low-energy devices should be developed for potential water disinfection, enabling safe drinking water access. Recently, many researchers have been working on improving the scalability and economics of nanomaterial-based devices to overcome many of the limitations of using traditional anti-microbial agents. Herein, we develop a safe and efficient new nanomaterial decontamination device targeting bacteria in drinking water. Zinc Oxide (ZnO) Nanowires and polyurethane sponges were utilized as affordable and available materials that would lower the cost of the filtration device. The device is based on an electroporation method that applies a low voltage of ~6 V to inactivated bacteria in water. The performance of our device was optimized using different values of voltages, flow rates, microorganism concentrations, and various operation times. By relying on nanotechnology-enabled electroporation principles, this method aims to address the limitations of traditional techniques and offer a feasible solution, especially in areas grappling with contamination issues that lack water treatment infrastructure.

A multiple applications study of motile microorganisms past a vertical surface with double‐diffusive binary base fluid

AbstractThis study investigates the various uses of density of motile microorganisms in the context of the flow of a binary base fluid with double diffusion past a vertical surface. The research aims to comprehend the interactions between motile microorganisms and the fluid dynamics, as well as the heat and mass transport mechanisms in this system. The analysis involves mathematically constructing the governing equations, transforming them into dimensionless nonlinear ordinary differential equations using similarity transformations, and numerically solving them using the MATLAB bvp4c solver. An analysis of the influence of several parameters on the profiles of velocity, temperature, concentration, nanoparticle concentration, and density of motile microorganisms is conducted using graphical representation. The findings demonstrate that boosting the thermophoresis parameter intensifies the temperature profile. In addition, an increase in the nanofluid Schmidt number results in a larger concentration of nanoparticles, whereas a higher bioconvection Lewis number reduces the density of the motile microorganism profile. These findings may find use in biomedical engineering as well as industrial processes that include enhancing the efficiency of mass transfer and bioconvection. Numeric simulation prophesies 99.9% for both shear stress and heat transfer rate intensification for Prandtl values are noticed.

Simulation of magneto-nano-bioconvective coating flow with blowing and multiple slip effects

The phenomenon of bioconvecton due to motile microorganism swimming patterns has been found to be a beneficial mechanism in many biological processes and microdevices. Inducing convective transport in self-propelling microbes has been successfully used to enhance mixing, reaction propensity and concentration transport within a range of engineered devices. Doping materials with microorganisms can also be implemented to manipulate magnetohydrodynamic coating processes with smart functional liquids, in which the substrate may be planar, wedge-shaped, curved etc. Inspired by this application, the current article examines theoretically and numerically the external boundary layer Falkner-Skan flow of an electroconductive nanofluid containing gyrotactic micro-organisms on a two-dimensional wedge with Stefan blowing and different slip effects at the wedge boundary. The physico-mathematical model is formulated using a system of partial differential equations and appropriate boundary conditions which are then transformed to a system of ordinary differential equations with appropriate similarity variables. The non-dimensional boundary value problem is solved numerically with the aid of the Mathematica software solver package named “NDSolve.” The impacts of the Stefan blowing, velocity, thermal, nanoparticle concentration and microorganism slips, magnetic number, Lewis number, bioconvection Lewis number, the Falkner-Skan wedge parameter, bioconvection Péclet number, thermophoresis and Brownian motion on key transport characteristics that is, dimensionless velocity, temperature, nanoparticle concentration (volume fraction), microorganism concentration, skin friction coefficient, local heat transfer rate (local Nusselt number), local mass transfer rate (local Sherwood number), and the microorganism local density number gradient are computed and visualized graphically. Numerical solutions are validated with previous literature. The outcomes reported in this paper are relevant to the synthesis of functional bio-nanopolymers.

Significance of variable thermal conductivity and suction/injection in unsteady MHD mixed convection flow of Casson Williamson nanofluid through heat and mass transport with gyrotactic microorganisms

AbstractThe present paper explores a two‐dimensional mixed bio‐convective unsteady viscous hydro‐magnetic Casson Williamson nanofluid flow model with heat and mass transport incorporating motile microorganisms towards a stretchy spinning disc. The flow concept is accomplished by rotating a stretched disc with a time‐varying angular velocity. By applying a magnetic field normal to the axial direction, a magnetic interaction is taken into consideration. The Casson Williamson nanofluid contains nanosized particles suspended with swimming motile microorganisms and the rotation of the disc is exhibited by buoyancy forces, thermophoresis, suction/injection, zero mass flux conditions, variable thermal conductivity, Joule heating and so forth. The obtained flow narrating differential equations of the model are transformed into ordinary differential system. This is accomplished by simulating boundary value problems using the shooting technique using the ‘ND‐Solve’ approach included in the Mathematica software (Mathematica 12). The implications of the engaged parameters such as Williamson fluid parameter, Casson fluid (CF) parameter, thermophoresis parameter, Brownian motion parameter and so forth, on both axial and radial velocities, temperature, concentration of nanoparticles and microorganisms are explained by means of graphical and tabular constructions. This paper's validity has been confirmed and its findings align with those of other previously published papers. Furthermore, it is found that both the axial and radial velocity profiles are seen to be diminishing functions of the CF parameter. The identified observation may have theoretical implications for a number of engineering procedures, solar energy systems, biofuel cells and extrusion system improvement. Moreover, this work finds application in micro‐fabrication techniques and the chemical industry.

Numerical Simulation of Bioconvection Maxwell Nanofluid Flow due to Stretching/Shrinking Cylinder with Gyrotactic Motile Microorganisms: A Biofuel Applications

The bioconvection effects with nanofluid are major application in biofuels. This analysis aimed to observe the bioconvection effect in unsteady two-dimensional Maxwell nanofluid flow containing gyrotactic motile microorganisms across a stretching/shrinking cylinder evaluating the consequences of thermal radiation and activation energy. The Cattaneo-Christov double diffusion theory is also observed. Nanofluids are quickly perceptive into many solicitations in the latest technology. The current research has noteworthy implementations in the modern nanotechnology, microelectronics, nano-biopolymer field, biomedicine, biotechnology, treatment of cancer therapy, cooling of atomic reactors, fuel cells, and power generation. By using the proper similarity transformation, the partial differential equations that serve as the basis for the current study are gradually reduced to a set of highly nonlinear forms of ordinary differential equations, which are then numerically, approached using a well-known shooting scheme and the bvp4c tool of the MATLAB software. Investigated is the profile behavior of the flow regulating parameters for the velocity field, thermal field, and volumetric concentration of nanoparticles and microorganisms. From the results, it is concluded that velocity is reduced with a larger bioconvection Rayleigh number. The thermal field is increased with a larger amount of thermal Biot number and thermal radiation. The concentration of nanoparticles increases with an increment in the thermophoresis parameter. Furthermore, the microorganism’s field is decreased with a larger Lewis number. The findings demonstrate that by optimizing the concentration of nanoparticles and microorganisms, the thermal efficiency of biofuels can be significantly improved. This leads to more sustainable and efficient energy production. By optimizing the concentration of nanoparticles and microorganisms in biofuels, the thermal properties can be significantly improved, leading to more efficient combustion processes. This can reduce the overall cost and increase the yield of biofuels. Improved cooling systems for medical imaging devices such as MRI machines can be developed using nanofluids, ensuring better performance and patient safety.

Productive and Ruminal Microbiological Behavior of Sheep Fed with Two Levels of Dehydrated Orange Residue

Objective: To evaluate the productive and ruminal microbiological behavior of sheep fed with two levels of dehydrated orange residue (DOR). Design/methodology/approach: Thirty Dorper x Katahdin crossbred male sheep with an average live weight of 22 ± 1.0 kg were distributed in a completely randomized design, with three treatments and ten repetitions. The distribution of treatments was as follows: T1 = diet with 0% DOR (control), T2 = diet with 15% DOR, and T3 = diet with 30% DOR. The variables evaluated were daily weight gain, dry matter intake, feed conversion, ruminal pH, and microbiological analysis. Results: There were no significant differences (p>0.05) in the productive variables due to the inclusion of DOR in the diet. Similarly, the concentration of ruminal microorganisms did not present significant differences between treatments. Study limitations/implications: The study did not include an economic analysis that would demonstrate a reduction in production costs by decreasing the inclusion of maize in the diet. Conclusions: Maize grain is one of the most commonly used cereals as an energy source in sheep feeding; however, it can be replaced by DOR up to 30% without affecting the productive and ruminal microbiological variables in fattening sheep.

An Alternative Microbiological Validation for an Online Water Bioburden Analyzer.

The Mettler-Toledo 7000RMS analyzer is a bio-fluorescent particle counter (BFPC) used to monitor real-time bioburden results from purified water (PW). Validation of the analyzer using 13 microorganisms and a low-intensity, fluorescent, polystyrene bead. During the execution of the validation, a laboratory water system that met PW quality standards was connected to the 7000RMS, and a syringe pump was used to introduce various concentrations of microorganisms and fluorescent polystyrene beads to the analyzer. Samples were collected and tested via the traditional membrane filtration (MF) method and the colony-forming unit (CFU) plate count results were compared to the auto-fluorescent unit (AFU) of the 7000RMS analyzer. The validation study was designed to follow the guidance in United States Pharmacopeia (USP) Chapter <1223>, European Pharmacopeia (EP) Chapter 5.1.6, and parenteral drug association (PDA) Technical Report 33. Concepts and strategies were adapted from EP Chapter 2.6.12 Microbiological Examination of Non-Sterile Products: Microbial Enumeration Tests, EP Chapter 10.2, EP Chapter 2.6.1 Sterility, USP Chapter <61> Microbiological Examination of Non-Sterile Products: Microbial Enumeration Tests, USP Chapter <71> Sterility Tests, and Japanese Pharmacopoeia (JP) General Information Chapter G8 Water: Quality Control of Water for Pharmaceutical Use. All pre-determined validation acceptance criteria for accuracy, specificity, precision, LOD, LOQ, linearity, and range were met. The 7000RMS demonstrated performance equivalence to the MF method per USP <1223> but characteristically lacked correlation to the CFU. This validation approach highlights the superior capabilities of the 7000RMS when compared against the traditional compendial MF testing method for PW.

Dependence of the concentrations of culturable microorganisms and total protein on meteorological conditions in the Novosibirsk surroundings

Dependence of the concentrations of culturable microorganisms and total protein on meteorological conditions in the Novosibirsk surroundings

Effect of Calcium Chloride on Chitosan Behavior in an Acidic Water Mixture for Pharmaceutical and Biomedical Applications

The present article reviews the uses of the biopolymer chitosan (CH) and its derivatives as versatile biomaterials for potential drug delivery systems, as well as for tissue engineering applications, analgesia and treatment of arthritis. CH and its derivatives, as natural antimicrobial agents, can be applied in biomedical, biotechnological, and pharmaceutical applications. Its antimicrobial activity depends on many factors, such as its molecular size, source, associated components, concentration and type of microorganism. In addition, in our research described here, we prepared and characterized the dynamic viscosity and the rheological properties of a biopolymer material based on CH/CaCl2 in solution. The dynamic viscosity and shear stress were measured under the influence of an increasing CH concentration of 1 to 10 g/l and an increasing temperature of 288.15 to 318.15 K.

Comparison of the Concentration of Local Microorganisms (MOL) in Stale Rice During the Composting Process

Background: The symbiotic relationship between microorganisms, specifically decomposing bacteria, and organic material, such as organic waste, leads to the decomposition of the substance and its transformation into compost. Objective: The aim of this study is to assess the efficacy of local microorganisms (MOL) tape in accelerating the decomposition process of organic waste compost. Methods: This research used an experimental study strategy known as "control with posttest". This investigation was conducted utilising two distinct groups: the control group and the treatment group. Regarding the intervention group utilising indigenous microorganisms (MOL) stale rice, the research utilised two data analyses: univariate analysis, which involved presenting data in the form of frequency distribution tables, and bivariate analysis, which included conducting a one-way Anova test followed by an LSD test. Results: The findings indicated that the optimal dosage of a local microorganism (MOL) activator for compost formation was 25 ml, resulting in a duration of 11.6 days. The statistical analysis revealed a significant difference (p &lt; 0.05) in the duration of compost formation between the dosage levels of 10 ml, 15 ml, 20 ml, and 25 ml of the local microorganism (MOL) activator. Conclusions: This research aims to explore the potential of MOL activators in accelerating the composting process of organic waste. By utilising MOL activators, it is anticipated that the problem of slow composting can be effectively addressed, offering a viable solution for the community. Moreover, the ease and affordability of producing MOL activators further enhance their practicality.

Neural network-based thermal analysis of stratified nanostructured materials with couple-stress nanofluid flow and gyrotactic microorganisms under exponential heating/cooling conditions

The heterogeneous fluid model is expressed for the nanofluid flow to study the significance of the Fourier’s and Fick’s laws. The magnetohydrodynamics couple-stress bioconvective nanofluid flow is considered across an extending surface with the effect of exponential heat source/sink and stratified boundary conditions. The solid nanoparticulates and concentrations of motile microorganisms are added to the nonlinear system of differential equations conveying the non-Newtonian nanoliquid flow model. Moreover, the combined effect of the heat flux and thermal radiation is also evaluated. The similarity transformations are employed to transfigure the system of partial differential equations into the lowest order of ordinary differential equations. The Artificial Neural Network Levenberg Marquardt Back-propagation optimization algorithm is employed to solve these equations. To authenticate the outcomes, the dataset is formed using the MATLAB package “bvp4c”. The dataset is created for diverse circumstances of flow factors, as well as validation and testing of the Artificial Neural Network. The accuracy of the model is estimated through numerous statistical tools (histogram, curve fitting, regression measures, and performance plots). The outcomes are presented through the table and figures. It has been noticed that the couple-stress nanofluid flow declines with the influence of magnetic field and mixed convection. The couple-stress nanofluid temperature augments with the enhancement of the thermophoresis effect, buoyancy ratio factor, Rayleigh number, and thermal radiation. Moreover, the concentration curve lessens under the impact of the Lewis number while enriched with the outcome of the concentration stratification parameter. The absolute error of reference and targeted date is attained within 10[Formula: see text]–10[Formula: see text] that proves the exceptional precision of the results.

Investigating the Thermal Efficiency of Al2O3–Cu–CuO–Cobalt with Engine Oil Tetra-Hybrid Nanofluid with Motile Gyrotactic Microorganisms Under Suction and Injection Scenarios: Response Surface Optimization

Nanofluids, due to their complex behavior and enhanced thermal properties, are utilized across chemical, biotechnology and thermal engineering disciplines. They are particularly integral to heat transfer processes in heavy machinery and vehicles. This study introduces a novel method for analyzing heat transfer within a tetra nanofluid system through a hybrid analytical and numerical approach. Our research primarily examines the dynamics of a magneto Williamson hybrid tetra nanofluid embedded with motile gyrotactic microorganisms. The study is designed around two scenarios: one investigates the behavior of an Al2O3–Cu–CuO–Cobalt/Engine oil nanofluid under suction conditions, and the other under injection conditions. By employing similarity variables, we transform the original fluid flow equations into nonlinear differential equations to further explore the influence of various physical parameters on the fluid’s flow. Such parameters include the nanofluid temperature and velocity as well as the concentration of nanoparticles, and the volume fraction of motile gyrotactic microorganisms. The optimization of the numerical results for skin friction, Nusselt number, Sherwood number and microorganisms concentration is validated through response surface optimization techniques. Additionally, the study utilizes Matlab‘s bvp4c function to examine the thermal efficiency and characteristics of fluid flow across a spectrum of parameter values.

Improved automated spot counting and modeling with bias correction

ABSTRACT A complete workflow was presented for estimating the concentration of microorganisms in biological samples by automatically counting spots that represent viral plaque forming units (PFU) bacterial colony forming units (CFU), or spot forming units (SFU) in images, and modeling the counts. The workflow was designed for processing images from dilution series but can also be applied to stand-alone images. The accuracy of the methods was greatly improved by adding a newly developed bias correction method. When the spots in images are densely populated, the probability of spot overlapping increases, leading to systematic undercounting. In this paper, this undercount issue was addressed in an empirical way. The proposed empirical bias correction method utilized synthetic images with known spot sizes and counts as a training set, enabling the development of an effective bias correction function using a thin-plate spline model. Its application focused on the bias correction for the automated spot counting algorithm LoST proposed by Lin et al. Simulation results demonstrated that the empirical bias correction significantly improved spot counts, reducing bias for both fixed and random spot sizes and counts.