Strategy for the Choice of Disinfectants in Practical Medicine and Production

Abstract

The problem of the strategy for choosing disinfectants in practical medicine is considered. The pandemic of the new coronavirus infection posed new problems for disinfectology. The expanded spectrum of disinfectants and antiseptics offered by the chemical industry in recent years requires justification for the choice in favor of any product. The goals and types of disinfection considered from current positions and the main groups of disinfectants used in Russia and their properties and spectra of activity are presented.

Aseptic, antiseptic, disinfection, and sterilization methods have expanded considerably in the last decades. On one hand, this has significantly increased the quality of the medical aid provided and, on the other, led to the spread of resistant strains of agents capable of causing infections associated with the provision of medical aid. Chemical disinfectants (CDs) of various compositions and concentrations are widely used to clean and disinfect surfaces, instruments, and tools; to decontaminate water and air, and to clean hands of personnel in medical institutions and the pharmaceutical and biotechnological industries. However, the choice of agent is difficult because the spectrum of agents offered by industry is extremely broad. Besides, a long list of problems with the application of disinfectants and antiseptics that require attention and resolution has developed over time.

The aim of the work was to systematize information on disinfection and disinfectants considering current trends for an informed choice of agents in practice.

Experimental Part

The search for information used keywords in electronic databases such as PubMed, e-library.ru, cyberleninka.ru, and researchgate.net and published sources during 2015 – 2022 without limiting the languages.

The selection criteria were epidemiological studies, clinical trials, cohorts, crossover studies, before-after studies, etc. The main criterion was problems in current practice of application of disinfectants and antiseptics in medical institutions.

Results and Discussion

Disinfection in medical institutions and pharmaceutical and biotechnological industries is intended mainly to ensure the infectious and epidemiological safety of patients, to improve the quality of provided medical aid and services, and to prevent spread of infections [1, 2]. This problem is becoming more and more critical considering the global nature of the spread of infections associated with provision of medical aid in medical institutions [3] and the increasing number of their vectors resistant to antiseptics [4]. CDs must be correctly chosen to assure the appropriate quality of the disinfection so that their use will meet regulatory requirements applicable to microbiological cleanliness of rooms and objects of medical institutions and pharmaceutical production [5].

The Russian market for CDs includes 1200 products of various CD groups. Domestic and foreign products are added to this lest every year [6, 7]. Recently, the following problems with disinfectants have become obvious:

( not all registered CDs met the requirements applicable to them with respect to composition, problems, and instructions for use [8];

( the instructions and effective concentrations are unclearly defined for several CDs [9];

( the need has arisen to determine clear criteria for defining a microorganism as resistant to CDs by establishing epidemiological threshold values and standardizing protocols for tests of microorganism resistance to CDs [10, 11];

( manufacturing conditions and the raw-material availability of manufacturers change;

( attention to the ecological safety of CD manufacturing has increased [12, 13];

– several CDs used in several institutions aged unreliably and had confirmed toxicity and corrosion hazards for surfaces and materials [14];

– morphological, biological, and genetic features of bacterial vectors of nosocomial infections especially resistant to disinfectants are insufficiently studied [11, 15];

– microorganisms acquire resistance to CDs, like to antibiotics and chemotherapy drugs, resulting in resistant strains of industrial microbiota [16] and, as a result, affect the quality of provided medical services and infection hazards [17];

– new infection issues present new problems for the development and use of new CDs. For example, the virus vector of the new coronavirus infection COVID-19 can persist on surfaces although the exact role of contaminated industrial and household items in the spread of the infection is still not established and the effectiveness of disinfection measures outside treatment and prevention institutes (TPIs) has not been confirmed [18];

– broad use of CDs and antiseptics because of outbreaks of the new coronavirus infection COVID-19 led to the use of antiseptics unsuitable for the community and incorrect handling and use of biocides [10, 19];

– incorrect use of CDs in TPIs and the unjustified expense of CDs for preparing working solutions exacerbate the problem of microorganism resistance to CDs [19, 20];

– the insufficient potential of single agents for effective inactivation of viruses [21] and bacteria and fungi resistant to CDs.

CDs offered on the current Russian market are 97% domestic. This share increased considerably from five years ago when the fraction of Russian CDs was 80%. The whole volume of CDs consists of 74% disinfectants, the fraction of which also grew by 3%. Topical antiseptics, including moist disinfecting tissues, amount to 22%; soaps, 4%.

Registered CDs in the RF include 50% with one active ingredient; 36%, two active ingredients; 12%, three active ingredients; and 2%, CDs with four active ingredients. Some of the most popular CDs are quaternary ammonium compounds (QACs), which are very important cationic surfactants (CSAs). QACs are guanidine derivatives and trialkyl amines. These CDs are not volatile, have no sharp smell, and are very water-soluble. Several of them have washing properties, are stable, and do not damage treated objects. They possess selective bactericidal, fungicidal, and virucidal activity without exhibiting sporicidal activity, which necessitates the formulation of multicomponent CDs.

Guanidine derivatives are also typical CSAs according to their physicochemical properties, i.e., they possess bactericidal and virucidal activity. Polymeric guanidine derivatives can form films on cleaned surfaces, thereby prolonging their residual antimicrobial activity [2, 22].

Alkylamines are fatty acid derivatives. Amines are divided into primary, secondary, and tertiary depending on the number of H atoms replaced by alkyl radicals. CDs containing a tertiary amine or a diamine exhibit high bactericidal, fungicidal, and virucidal activity.

CDs containing alcohols that are used for disinfection include ethyl, isopropyl, or propyl alcohols. Agents based on alcohols are bactericidal, destroying vegetative microorganisms. They can destroy spore-forming microorganisms at concentrations >70%. Isopropyl alcohol at concentrations ≥60% kills tuberculosis mycobacteria [23]. The virucidal activity of these CDs is multifaceted. Lipophilic viruses are sensitive to the above three alcohols. Hydrophilic viruses (e.g., hepatitis A virus, Coxsackie enterovirus) are inactivated only by ethanol [23]. Disinfectants containing alcohols are costly. Therefore, they are used to clean small difficultly accessible equipment parts and surfaces and as additives to CDs based on QACs.

CDs now are most often combined, including QACs, 4.5 – 15%; guanidine, 1 – 10%; and amines, 4 – 10%. Alcohols are also added. In this instance, cleaning with concentrations from 0.05 to 0.2% for 30 – 60 min is used to wipe surfaces and achieve an antibacterial effect. Concentrations from 0.1 to 3% are used for 60 min to produce a virucidal effect. Medical instruments are cleaned and an overall microbiocidal effect is achieved if the concentration is increased to 4% and the treatment time, from 20 to 60 min. The concentration(time regime for sterilization should be increased to 25% and 60 – 120 min. Endoscopic equipment and medical tubing should be cleaned with CD solutions of concentrations 2 – 15% for at least 15 – 30 min.

Disinfection is an obligatory procedure in medical and pharmaceutical rooms. According to adopted sanitary rules and standards (SanPiN 1.2.3685(21, SanPiN 3.3686(21, SP 3.5.1378(03), objects to be disinfected include equipment, tools, fixtures, room surfaces, air, water, sanitary personnel clothing, whites, and bandages.

The purpose of disinfection is the prevention of generating and spreading infections associated with provision of medical aid (IAMA) [an outdated name for nosocomial infections (NIs)].

The task of disinfection is to disrupt transmission pathways of infectious disease vectors from infection sources to susceptible people (from an infectious patient to the environment).

The objects of disinfections can be divided into the following types:

( critical, come into contact with sterile tissue of an organism, e.g., cardiac catheters, implants, surgical instruments. Sterility requirements are applicable to critical objects;

– semicritical, come into direct contact with patient mucous membranes or damaged skin, e.g., inhalers, endoscopes, bronchoscopes;

– noncritical, contact intact skin fragments, e.g., bedpans, thermometers, stethoscopes.

Disinfection levels:

– High-level disinfection (HLD), aimed at destroying vegetative bacteria, tuberculosis mycobacteria, fungi, and lipid and nonlipid viruses. HLD is ineffective against many bacterial spore forms. HLD is used for semicritical objects.

Mid-level disinfection (MLD), aimed at destroying vegetative bacteria, most fungi, tuberculosis mycobacteria, most viruses. It is ineffective against bacterial spore forms. MLD is used for semicritical and noncritical objects with smooth solid surfaces;

Low-level disinfection (LLD), aimed at destroying vegetative bacteria, several fungi, viruses. It is ineffective against highly resistant bacteria (tuberculosis mycobacteria) and bacterial spore forms. LLD is used for noncritical objects.

Many factors determine the choice of CD. Many criteria should be considered [24].

The staging and sequencing of a comprehensive cleaning and disinfection, from the cleanest zones to the most contaminated, from above to below, concentrating grime and contaminants near the floor, from where they can be removed by CDs of the highest concentrations are important components.

The choice of CD for cleaning hands tends to favor CDs packaged into dispensers that prevent contamination of the tank and the solution itself.

Surfaces are disinfected during routine and general cleaning using CD solutions by wiping with cloths wetted with a CD solution. CDs with a detergent effect should be used for these purposes. If the need for emergency cleaning of small or difficultly accessible surfaces arises during the working day, finished CDs with short service lives, e.g., those based on alcohols, can be used with squirt bottles or wiping with CD solutions on cloths or ready-to-use disinfecting pads. The use of CDs with detergent properties allows decontamination of an object to be combined with its washing. Therefore, disinfecting agents with detergent action are used for routine and general cleaning. Increased attention should be paid to monitoring cleaning in TPIs [25, 26].

Labware is disinfected with agents based on aldehydes, CSAs, H₂O₂, and chlorinated agents. Items and labware are disinfected by immersion in CD solutions. Items that can be disassembled are disinfected as their parts. Channels and cavities of items are filled with disinfecting solution.

Batches of CDs newly arriving at a warehouse must be monitored for the content of active ingredient. Disinfecting solutions are prepared in specially separated rooms or hoods following the instructions for dilution. The name, concentration, and date of preparation should be indicated on a container with disinfecting solution.

Cleaning supplies should be labeled separately for clean and contaminated zones. Transfer from one zone to another is not allowed.

The choice of CD is determined by the effectiveness against microorganisms that must be eliminated, i.e., the microorganisms most often encountered in the industrial environment for which industrial microbiological monitoring is required [27, 28].

CDs must be tested on all types of surfaces susceptible to contamination in an actual production for a reliable choice of CD for a particular object because the CD can behave differently on different surfaces [2, 29]. Studies on surfaces should mimic the actual cleaning process that will be used daily by personnel.

The choice of CD must also consider potential toxic effects on personnel performing the cleaning and on the production equipment, including the formation of residues that may become the cause for endotoxin formation [30].

Expanded morphological and biological studies of the nature of bacterial resistance to a CD to model the process by which bacteria require resistance to it are needed to improve the choice of CD. Considering the expanding resistance spectrum of bacteria to CDs in medical and pharmaceutical institutions, the principle of CD rotation must be used.

Thus, the choice of CD is determined by the following factors:

• The contaminating microbial vector of the production zone of medical and pharmaceutical institutions and the level and degree of resistance;

• Recommended concentration(time regimes for action of working solutions, purpose of the disinfection;

• Surface nature and material, its corrosion resistance, configuration of object to be cleaned;

• CD toxicity criteria;

• CD stability, shelf life for 100% effectiveness;

• Convenience of packaging for use;

• Requirements of healthcare organizations, Russian and departmental regulatory documents, approval of CD for circulation.