Antimicrobial efficacy methods

The essential oil composition and antimicrobial activity of Osmitopsis asteriscoides (Berg) Less, a medicinal plant used in traditional preparations in South Africa has been investigated [125]. Three different antimicrobial methods were comparatively evaluated against Candida albicans. Staphylococcus aureus and Pseudomonas aeruginosa The two major essential oil components, camphor. Fig. (1) and 1,8-cineole, Fig. (2) were investigated, indieating the positive antimicrobial efficacy of 1,8-cineole, Fig. (2), independently and in combination with camphor, Fig. (1). 

Many antimicrobial efficacy evaluations of topical antimicrobial products involve measurements of microbial population reductions at a specific time point after exposure to the product. To determine this accurately, the antimicrobial action of the product must be stopped at the time specified for sample, and it is for this action that neutralizer systems are employed. The validity of the neutralizer system must be established prior to performing the antimicrobial efficacy test. This concern for neutralizer validity has long been known, and a number of methods have been proposed for validating neutralizer systems [1-5]. Each of the methods focuses on two major concerns (1) the neutralizer system must demonstrably neutralize the antimicrobial properties of the product, and (2) the neutralizer system must be proven nontoxic to the test microorganism(s). Few validation methods apply techniques of statistical analysis to the determination of their validity... 

Topical antimicrobial efficacy tests comprise test methods similar to those outlined in the Food and Drug Administration s Tentative Final Monograph for Healthcare Antiseptic Drug Products time-kill kinetic studies effectiveness testing of a surgical hand scrub effectiveness testing of an antiseptic handwash or... 

This chapter presented a statistically based method for validating neutralizing systems used in topical antimicrobial efficacy evaluations. This method should be performed prior to performing a topical antimicrobial efficacy evaluation so that the researcher can be assured that the neutralizing system to be used will,... 

In many advanced countries there are legal restrictions on the claims that can be made about antimicrobials, because they are not all completely effective in killing all microorganisms. So expressions like self-sterilising , hygienic and germ-ifee are associated with specific levels of performance and not automatically acceptable just because a biocide is used. As a result, there has been considerable interest in the development of appropriate test methods for measuring antimicrobial efficacy. 

The antimicrobial efficacy of the amine-formaldehyde reaction products essentially corresponds to the formaldehyde content of these compounds. Known exceptions are HTA, hexahydro-oxadiazines and octahydro-s-tetrazines, which derive from ammonia respectively certain alkylolhydrazines (Paulus, 1980) here the detection of formaldehyde by the Taimenbaum methods gives a negative result, which means that these substances have no significant antimicrobial effect at neutral to alkaline pH they release formaldehyde in acidic media only. This pH dependency is broken off, if, for example, HTA is quatemized (Jacobs et al., 1916). In contrast to HTA the quaternary hexaminium salts release formaldehyde widely independent of pH and therefore may be used as preservatives also for media of neutral to alkaline pH. They are not comparable with the surface active conventional quaternary ammonium compounds (QACs see Section 16.1)... 

The ZOI test, also widely known as the Kirby-Bauer disk diffusion test, is a fast in vitro but semiquantitative test [169], The original purpose of this test was to replace the MIC test for small molecule antibiotic efficacy [169], Soon, this method was adopted and modified to evaluate antimicrobial efficacy of silver and polymeric devices with eluting antimicrobial agents [170], Conunonly used eluting antimicrobial agents are zinc salt/particles [171-173], silver salt/particles [173-177], and chlorhexi-dine [178,179], These antimicrobial agents can be compounded/blended into polyurethanes or coated/adsorbed on polyurethanes. 

The library of silver-NHC compounds has been greatly expanded due to the contributions of Tacke and coworkers (13a-21) [13-17] and Roland et al. (22a-25b) [18]. Compounds 13a-21 (Figure 6.1), all bearing the acetate ligand, were evaluated for their antimicrobial efficacy against S. aureus and . coli using a qualitative Kirby-Bauer disk-diffusion method. The imidazolium salt precursors, silver acetate, and the vehicle (dimethylsulfoxide) served as controls. The results of the tests were mixed, with a number of compounds having a weak... 

Koch discovered the methods to evaluate the antimicrobial efficacy of disinfectants. 

There are a number of test methods that can be used to determine antimicrobial efficacy as well as biocompatibility of treated articles. Standards setting organizations such as the American Society for Testing and Materials (ASTM) and American Association of Textile Chemist and Colorist (AATCC) provide standard test methods that can be used to show antimicrobial efficacy of treated articles. There are also other efficacy test methods that fall outside the purview of these two organizations that are very effective. The ISO Technical Committee 194 has developed the ISO 10993 biocompatibility series which address the biological evaluation of medical devices including standards for those treated with antimicrobials. 

Because the halogenated hydantoins are anchored and do not readily release fi ee chlorine, conventional methods for demonstrating antimicrobial efficacy based on the diffusive release of fi ee biocide into the local microenvironment— the so-called zone of microbial inhibition— cannot be applied. Inhibitory zones are minimal under circumstances where the challenge method depends on the slow release of biocides into an area populated by growing organisms, the net effect of which is to kill those which fall within a range of concentrations that is lethal. Retention of Cl on the grafted hydantoin demands that a test method be... 

In 1998, a CEFIC working group composed of industry experts from EPAS (European Producers of Antimicrobial Substances) and EPFP (European Producers of Formulated Preservatives) compiled a listing of over 200 relevant efficacy testing methods and around 100 of these were critically analysed in... 

The validation method for neutralizing the antimicrobial properties of a product must meet two criteria — neutralizer efficacy and neutralizer toxicity. The validation study documents that the neutralization method applied is effective in inhibiting the antimicrobial properties of the product (neutralizer efficacy) without impairing the recovery of viable microorganisms (neutralizer toxicity). Validation protocol may meet these two criteria by comparing recovery results for three treatment groups. 

The purpose of this example is to demonstrate the efficacy of a silver composition of the present invention against the bacteria that cause tuberculosis. This example describes the procedures for evaluation of the present invention for tuberculocidal efficacy. The methodology is based on the Tuberculocidal Activity Test Method as accepted by the EPAon Dec. 11, 1985. [Refer to United States Environmental Protection Agency, 1986. Office of Pesticides and Toxic Substances. Data Call-In Notice for Tubercuolocidal Effectiveness Data for All Antimicrobial Pesticides with Tuberculocidal Claims. (Received Jun. 13, 1986). 

Liquid formulations for parenteral use require preparation methods and composition that make the formulation stable and sterile. Other requirements for parenteral formulations are given by the European Pharmacopoeia such as tonicity, efficacy of the antimicrobial... 

The clinician should have an understanding of in vivo antimicrobial agent disposition in order to select the most appropriate therapy for a given infection and to help monitor for clinical or bacteri-ologic efficacy. Serum concentration monitoring is the most common method used to attempt to maximize efficacy and minimize toxicity of antimicrobials. Since most antimicrobials are well tolerated at their usual doses, only a select few agents (e.g., aminoglycosides, chloramphenicol, and vancomycin) are monitored routinely in the current clinical environment. There are a number of direct and indirect methods that are used to quantify the concentration of antimicrobial in an experimental sample. 

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