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Implications of Sampling and Chemistry
Published in Richard B. Eckert, Torben Lund Skovhus, Failure Analysis of Microbiologically Influenced Corrosion, 2021
Kelly A. Hawboldt, Christina S. Bottaro, Abdulhaqq Ibrahim, Mahsan Basafa, Angham Saeed
MIC is impacted by many factors including the chemistry of the environment (e.g.,, produced water vs crude oil), temperature, pressure, pH, material degradation, in addition to the composition of the microbial community. These factors are well understood with respect to promoting or inhibiting MIC, but there is less knowledge on the chemical interaction between the fluid, microbes, and corrosion products and subsequent impact on rate and extent of MIC. This is particularly true for the dynamic nature of the chemistry of the surrounding environment (due to changes in temperature, pressure, pH, etc.) on microbial growth or corrosion products and the subsequent impact on MIC. The first steps in attempting to capture these interactions are the accurate detection and measurement of key compounds involved in MIC in the process stream, as well as the dominant chemical reactions/interactions as a function of temperature, pressure, and pH. This chapter is focused on discussing proper sampling protocols to maintain sample integrity in the field and for transport so key compounds can be identified. We provide a summary of analytical methods (field and lab) to detect and measure these compounds and a summary of key chemical reactions occurring in oil and gas production platforms/sites that could influence MIC.
Oral Administration of Lipid-Based Delivery Systems to Combat Infectious Diseases
Published in Ana Rute Neves, Salette Reis, Nanoparticles in Life Sciences and Biomedicine, 2018
Rita M. Pinto, Daniela Lopes, Cláudia Nunes, Bruno Sarmento, Salette Reis
In vitro assays are valuable tools to assess the therapeutic efficacy of antimicrobial NPs. For bacteria, in vitro antimicrobial activity studies are based on the determination of the minimum inhibitory concentration (MIC) and of the minimum bactericidal concentration (MBC) [107]. The MIC can be defined as the lowest concentration of a antimicrobial agent required to inhibit visible growth of an inoculum of the bacterium in a broth dilution test [108]. On other hand, MBC is the minimal concentration of a antimicrobial agent able to kill ≥99.9% of the initial inoculum within 24 h, and it is determined from broth dilution MIC tests by subculturing onto antibiotic-free agar media [108]. For instance, in the work of Dong et al. serial dilutions of NP suspensions were mixed with S. aureus to a final bacterial concentration of 5.5 × 105 CFU/mL [73]. The mixture was posteriorly incubated at 37°C for 12 h and 24 h, with shaking [73]. Usually, the MIC is determined by a visual comparison of the medium turbidity of the cultures and the control tubes [108]. Alternatively, the MIC value can be determined by spectroscopy [110]. MBC is measured by subculturing the broths previously used for MIC measurement onto fresh agar plates at 37°C [73]. Therefore, the microbial colonies are counted when they are observed by the naked eye [73]. Besides the determination of MIC and MBC, studies of NP-pathogen interactions can be performed, such as agglutination assays, epifluorescence studies, TEM technique, and quantification of bacterial adhesion using luminescence [19]. These studies are reported in more detail elsewhere [19].
Polymer–Silver Nanocomposites: Preparation, Characterisation and Antibacterial Mechanism
Published in Huiliang Cao, Silver Nanoparticles for Antibacterial Devices, 2017
The minimum inhibitory concentration (MIC) of the antimicrobial agent is the lowest concentration that inhibited visible growth of the microorganism in a susceptibility test, and it is determined according to the guidelines of the Clinical and Laboratory Standards Institute (2006).
Studies on a new antimicrobial peptide from Vibrio proteolyticus MT110
Published in Preparative Biochemistry & Biotechnology, 2023
Himanshu Verma, Kanti N. Mihooliya, Jitender Nandal, Debendra K. Sahoo
MIC is defined as the minimum concentration of the antimicrobial agent, which inhibits the visible growth of the test organism after incubation of 16–20 h under test conditions. In this study, the MIC of peptide-MT110 was determined against six indicator strains, i.e., S. aureus MTCC 1430, S. mutans MTCC 497, E. coli MTCC 1610, A. baumannii ATCC 19606, V. vulnificus MTCC 1146, and P. aeruginosa MTCC 1934 in microtiter plate using broth dilution assay, described by Wiegand et al.,[20] in which plates were incubated at 37 °C for 24 h, and the absorbance was read at 600 nm. The MBC of pure peptide-MT110 was determined using the method described by Tong et al. 2010,[21] with a few modifications. MBC is the lowest dose of antimicrobial agent that suppresses the observable growth of test organisms. For MBC, 10 μL from a 24 h incubated microtiter well plate of MIC, where no bacterial growth was detected, and distributed on different nutrient agar plates, incubated at 37 °C for 24 h and colony formation were evaluated; those plates where no colony was seen were considered MBC. All MBC tests were done three times.
Study of antibacterial and antioxidant activities of silver nanoparticles synthesized from Tradescantia pallida (purpurea) leaves extract
Published in Journal of Dispersion Science and Technology, 2023
Romana Naaz, Vasi Uddin Siddiqui, Amina Ahmad, Sami Ullah Qadir, Weqar Ahmad Siddiqi
MIC refers to the lowest concentration of antibiotic that prevents evident bacterial growth while MBC is the lowest concentration that kills 99% of bacteria after inoculation of the MIC for 24 hours. MIC techniques are commonly utilized to test novel medicines quantitatively or to obtain a more precise diagnosis or treatment.[46] By using a broth microdilution process, the MIC was determined. Serial concentrations of AgNPs were prepared in sterile 96-well plates, and the first-row plates (row A) were assigned to blank/negative and uncontrolled growth controls, using only MH broth media. A diluted overnight broth culture was added to each well, which ranged in concentration from 0.75 to 200 µg/mL, adjusted to a McFarland turbidity standard of 0.5.[47] The plates were then incubated for 24 hours at 37 °C. Following overnight incubation with an antibacterial drug (AgNPs) that prevents microorganism growth, the MIC and MBC was determined.[4,24]
Risk assessment of in vitro cytotoxicity, antioxidant and antimicrobial activities of Mentha piperita L. essential oil
Published in Journal of Toxicology and Environmental Health, Part A, 2022
W. M. F. Silva, N. P. Bona, N. S. Pedra, K. F. Da Cunha, A. M. Fiorentini, F. M. Stefanello, E. R. Zavareze, A. R. G. Dias
Minimum inhibitory concentration (MIC) is defined as the lowest concentration of antimicrobial agent able to inhibit the visible microbial growth (Balouiri, Sadiki, and Ibnsouda 2016). The MIC of PEO was determined by micro-dilution in 96-well plates, according to CLSI (CLSI, Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria That Grow Aerobically; Approved Standard – 13th Edition, 2019b). PEO was diluted in Brain Heart Infusion broth (BHI-Oxoid®) with 1% Tween 80 (Vetec®), and concentrations of 1.84 to 292 μg/ml obtained. Bacteria were added to obtain a final concentration of 104 CFU/ml in each well. As a negative control, only culture medium was used; for positive control, the culture medium plus bacterial inoculum was employed. In addition, a sterile PEO control was included. The plates were incubated at 37°C for 24 hr, and after, 10 μl of resazurin at 0.2% (Exodus®) was added to all wells followed by incubation at 36°C for 2 hr. The formation of pink staining indicated potential bacterial viability. MIC was considered as the lowest concentration at which visible bacterial growth was not observed.