Introduction
The evolutionary development of pathogenic microorganisms, expressed in increasing resistance to disinfectants, is a severe problem for clinical and domestic environments. Infectious diseases have high mortality rates, which means an urgent need for in-depth research into the effectiveness of disinfectants against various bacteria, viruses, and fungi. The author of this work supposes that, concerning pathogenic agents, there is variability in parameters influencing the effectiveness of disinfectant and the components’ multi-directionality. In particular, it is expected that molecules that inhibit the growth and vital functions of some microorganisms may be useless for others. The urgency of this problem for the author is confirmed by the desire to study the commercial viability of most of the means utilized, and for the academic community, by the pursuit to generalize the available knowledge and conduct a previously unrealized large-scale meta-experiment of disinfectants efficacy.
Literary Review
It should be recognized that a detailed study of the disinfectant effectiveness against pathogenic bacteria is of great importance for the medical and biochemical academic community. The literature review based on five primary sources was conducted to assess this area’s leading trends. It should be recognized that each of the words used was aimed at quantitative and then qualitative evaluation of a particular disinfector’s effectiveness for the elimination of a specific strain of pathogens. Thus, the study’s most frequently encountered objects were S. aureus (3/5) and P. aeruginosa (3/5). However, the total number of bacteria for which the study was conducted exceeded 18 strains. It is generally recognized that pathogenic infections are among the most important causes of high mortality among attenuated patients in hospital care, with about half of the cases of infection occurring through physical contact, namely, through hand surfaces (Tapouk et al., 2020). At the same time, about 25 American patients die every day due to infectious diseases (West, Nkemngong, et al., 2018). These data suggest an urgent need to investigate the effectiveness of disinfectants utilized to sterilize surfaces.
Despite the variety of conditions, a limited range of disinfectants is most commonly used in clinical practice. For instance, Tapouk et al. (2020) reported a high prevalence of three commercial sanitizers: MQ, DHLDPA, and Steranios 2%. Nevertheless, West, Nkemngong, et al. (2018) showed that most such agents’ central components are quaternary ammonium cations (QUATs). It is worth noting that the disinfectants demonstrate different efficacy concerning the tested strains (Tapouk et al., 2020; West, Teska, et al., 2018). In other words, it is necessary to practice various commercially available substances to sterilize the premises in order to reduce the level of pathogens.
In discussing the reasons for this phenomenon, the authors traditionally refer to the evolutionary principle of resistance development in strains to chemical agents. This problem has been mentioned by Lanjri et al. (2017) and formed the basis of the study Tapouk et al. (2020). Indeed, increasing the resistance of bacteria, viruses, and fungi is a serious problem, and therefore, a multi-faceted approach to the study prevailed among scientific papers: the authors of all five articles analyzed several disinfectants of different compositions. Among the agents that have shown the highest efficacy for all the strains under test are chlorhexidine (di)gluconate, hypochlorite, and the essence of 10% acetic and 0.5% citric acids (Lanjri et al., 2017; West, Nkemngong, et al., 2018; Zinn & Bockmuehl, 2020). Nevertheless, this recommendation should not be taken literally, as inadequate use of many agents may have an inhibitory effect due to pathogens’ ability to develop resistance rapidly. Instead, Tapouk et al. suggested using minimum inhibitory (MI) and minimum bactericidal (MB) concentrations as tools for selecting the disinfector.
Meanwhile, factors affecting the effectiveness of the disinfectant deserve special attention. It has been confirmed that the same disinfector showed different results at various concentrations, time of use, and active area of contact (West, Teska, et al., 2018; West, Nkemngong, et al., 2018; Lanjri et al., 2017). In particular, the dilution of ethyl alcohol doubles (up to 35%) increases the resistance index of pathogens to 25.92%, while for povidone-iodine, when diluted by a third, this number does not exceed 18.51%. Simultaneously, acetic acid itself is a weak disinfector, but the modification of the substance with citric acid allows getting a highly effective preparation even in the case of shell viruses. The spread area of the disinfector is crucial: although EPA does not regulate this parameter, it has been shown that increasing the surface fourfold significantly reduces the bactericidal effect of the substance (West, Nkemngong, et al., 2018). The study conducted by the author of this paper aims to obtain a quantitative and qualitative evaluation of the effectiveness of most disinfectants used. In other words, this work’s results will be useful not only for further testing in the field of biochemistry of microorganisms but also for the commercial market of disinfectants.
Hypothesis Staging
Research hypothesis: different disinfectants should be used to sterilize surfaces from different pathogens.
The null hypothesis, H0: there is no statistical significance between the effectiveness of different disinfectants.
Relationship to the study question: by conducting two parallel studies, a study of the limitations of disinfectants and a study of the stability of microorganisms, the author gives the as broadest as possible coverage of the questions posed in this paper.
Problem solution: by collecting enough known literature and conducting his research, the author will solve the problem and lay the foundation for future research.
Protocol
Materials and Methods
Five categories of data were proposed for utilizing in this trial: activity of microorganisms cultivated on a Petri dish, the concentration of the active inhibitor, contact time, contact area, and antiseptic. It is expected that by using these independent variables, the author will be able to obtain an overall objective picture illustrating the nature of the effect of different disinfectants on pathogens. The experiment is carried out on the platform of the University Laboratory, where for one week, there is a regular observation of fixed Petri dishes in which the observed strains are placed.
Seven different bacteria, common in literature and clinical practice, are utilized in the experiment, namely A. baumannii, E. faecalis, B. cepacia, S. aureus, P. aeruginosa, E. coli, and E. hire. In sterile conditions, the strains are cultivated on chocolate agar, for each strain, eight Petri dishes: a total of 5x7x8 test samples and 21 control (Ci) samples. The objects are placed in an incubator at room temperature and stable pressure. After 24 hours, when the strains began to spread across the substrate, the experimenter injects drops of disinfectants into the test cups:
- hypochlorite (“HCh”),
- ethanol (“Eth”),
- essences of acetic and citric acids (“Acids”),
- QUATs, (v) chlorhexidine (“CH”),
- povidone-iodine (“PI”),
- Steranios 2% (“S2%”),
- DHLDPA as shown in protocol table 1.
Table 1: Format of conducting tests; the free cells contain information about the viability of organisms and the effect of the disinfector.
Data Processing
The data collected on the vital functions of organisms includes parameters of growth, enzymatic activity, and color of the strain, along with the above five parameters of the experiment. These are quantitative data that are statistically processed using modern software. In particular, it is proposed to use a linear regression model, Cronbach’s alpha, t-test, and correlation coefficient to evaluate statistical significance. The completed article will be offered for publication in two famous publishing houses: Antimicrobial Resistance & Infection Control or BMC Microbiology.
References
Lanjri, S., Uwingabiye, J., Frikh, M., Abdellatifi, L., Kasouati, J., Maleb, A., & Elouennass, M. (2017). In vitro evaluation of the susceptibility of Acinetobacter baumannii isolates to antiseptics and disinfectants: comparison between clinical and environmental isolates. Antimicrobial Resistance & Infection Control, 6(1), 1-7. Web.
Tapouk, F. A., Nabizadeh, R., Mirzaei, N., Jazani, N. H., Yousefi, M., & Hasanloei, M. A. V. (2020). Comparative efficacy of hospital disinfectants against nosocomial infection pathogens. Antimicrobial Resistance & Infection Control, 9(1), 1-7. Web.
West, A. M., Nkemngong, C. A., Voorn, M. G., Wu, T., Li, X., Teska, P. J., & Oliver, H. F. (2018). Surface area wiped, product type, and target strain impact bactericidal efficacy of ready-to-use disinfectant Towelettes. Antimicrobial Resistance & Infection Control, 7(1), 1-8. Web.
West, A. M., Teska, P. J., Lineback, C. B., & Oliver, H. F. (2018). Strain, disinfectant, concentration, and contact time quantitatively impact disinfectant efficacy. Antimicrobial Resistance & Infection Control, 7(1), 1-8. Web.
Zinn, M. K., & Bockmuehl, D. (2020). Did Granny know best? Evaluating the antibacterial, antifungal and antiviral efficacy of acetic acid for home care procedures. BMC Microbiology, 20, 1-9. Web.