Die bacteria, die…

By: Tamara Carolina Echeverría Macías

Doctor of Medicine

Today we will talk about antiseptics and disinfectants; shields against microorganisms. Have we ever heard that water and soap are the best disinfectants: common sense.

Firstly, I would like to describe the approach of this essay, with a significant question: Is there really an antiseptic or disinfectant that acts as a panacea (ideal remedy)? The answer will be provided based on the following analysis: a brief review of history; antiseptics, disinfectants, sterilizers; as well as their characteristics and comparisons; hospital chemical risks (chemical containment, exposure; and toxic chemicals in the healthcare area); along with the current context of the pandemic (Covid-19) that we have been experiencing for the past couple of years; finally, the conclusions of the analysis and future outlook.

Starting with history…

“Doctors are gentlemen and a gentleman’s hands are always clean.” Today, in 2024, it seems very reasonable and even a duty for doctors to have clean hands before performing a procedure. But in the 19th century, it was considered an insult to even suggest washing hands.

Ironically, there might have also been a lack of pockets in doctors’ coats back then, because surgeons would place sutures in their lapels, or even more incredibly; they would hold the scalpel with their teeth when both hands were occupied; or if it fell on the floor, they would pick it up without concern and continue the surgery.

Indeed, during that time, it was normal to see a doctor’s coat covered in blood and pus from the previous patient, going to attend to another patient without cleaning anything. Instead, the ideal practice back then was to wash hands only at the end of surgery. The problem was that so many people were dying (mostly from sepsis or gangrene) and the solution being considered was to cancel surgery altogether; or better yet, only operate when absolutely necessary.

Other measures were also implemented, such as airing hospital rooms to disperse miasmas (back then, the effluvia emitted by sick bodies). In my opinion, this latter measure constituted one of the initial steps toward considering patient isolation and reducing the spread or secondary infection of wounds.

The contributions of Dr. Joseph Lister, such as sterilizing surgery, in my view, have revolutionized the field of science significantly. Above all, he has left a great legacy in history because he managed to decrease mortality from surgical infections. He suspected that the cause of deaths was not simply miasmas but rather the patient’s wound. By cleaning wounds, he sometimes managed to contain infections.

In 1864, Dr. Lister encountered the work of scientist Louis Pasteur and, following his research, associated microorganisms causing putrefaction and fermentation with wound infections. He designed a sprayer for carbolic acid (now known as phenol), which was used to prevent wood decay in ships and railways at the time. His results were impressive because he achieved the healing of an open leg fracture without infection.

Since then, he began sharing his findings in The Lancet from 1867, stating, “(…) Doubts will not prevent the adoption of a useful procedure; (…) The complete exclusion of wound putrefaction (…) without efficient antiseptic measures would simply be homicidal (…).”

I appreciate what he said because, despite contemporary doctors initially dismissing the idea of microorganisms in wounds as impossible, this part of history fascinates me. I admire how the truth eventually came to light.

Considering also that thanks to other scientists like Koch (with his postulates on microorganisms) and Semmelweis (who reduced puerperal fever with handwashing), among many others, who contributed with their discoveries, in my opinion, all these events constituted an achievement that propelled Medicine forward. This step was monumental for its time, marking a significant before and after in the course of history.

Honoring Dr. Lister, mouth rinses like the famous Listerine were created. I believe it is undeniable that his contributions are part of our lives through something that has become a simple and routine habit: maintaining proper oral health.

This mouthwash is mainly composed of plant derivatives with various properties from essential oils: such as eucalyptol and thymol (antibacterial), menthol (germicidal), and methyl salicylate (aromatic and refreshing).

All of this makes me reflect because it’s ironic that health is not only achieved through doctors or medications, which often have more adverse effects than benefits, but it is right in front of our eyes: plants. Science has progressed significantly thanks to them.

I also believe that no matter how much humanity has “discovered” the cure that has always been within reach, there will always be a greater entity that provided from nature, which ensures our physical and mental well-being.

After this introduction, in the form of a brief summary of the history of antiseptics and disinfectants, I will clarify a couple of important concepts etymologically to continue with the thread of this essay, whose focus is directed towards resolving the question: Is there really an antiseptic or disinfectant like a panacea?

It is crucial to consider that not all microorganisms in our body are a threat to our lives; rather, they protect us, as I will explain further on.

Regarding antisepsis (anti: against; sepsis: decay or putrefaction), it refers to the use of chemical compounds to inhibit or destroy pathogenic microorganisms and can be applied to skin or living tissue. Asepsis (a: without; sepsis: putrefaction), on the other hand, is the absence of pathogenic microorganisms, aimed at reducing their transmission.

Disinfection (dis: apart; infection: frequent attack; ant: agent, action) involves the destruction of microorganisms found on inanimate objects, ensuring the elimination of vegetative forms but not bacterial spores. Sterilization (sterilis: barren) is the complete elimination of all forms of microbial life. Germicide (germenis: bud; cide: kill), therefore, destroys harmful microorganisms.

I’d like to metaphorically relate all this to an explosion because when the fire ignites the dynamite, the destruction is widespread. What happens to the microbiota (microorganisms in our tissues, usually healthy)? If the explosive or disinfectant does its job… it would also kill part of the resident microbiota (microorganisms throughout the body, on the skin, mucous membranes, serving protective and homeostatic functions). Rather, the focus of a germicide is to eliminate transient microbiota (which is generally pathogenic and can become opportunistic and deadly).

What I mean is that a disruption or imbalance in the immune barrier (for example, the skin) becomes the perfect entry point for various microorganisms. This underscores the importance of knowing how to correctly use an antiseptic or disinfectant and the appropriate timing for their application.

Specifically, the characteristics that must be met include having a broad spectrum of action, easy diffusion through pus or cellular debris, rapid action, and maintaining effectiveness for a considerable time period. Crucially, it should not harm tissues or damage objects or surfaces where it is applied. Achieving all these requirements is not feasible with a single antiseptic or disinfectant.

Furthermore, antiseptic or disinfectant actions are not without adverse effects. Ideally, they should have a low incidence of hypersensitivity development and control residual effects, as absorption could pose additional risks (for example, iodine has relative contraindications in premature newborns and pregnant women due to placental passage and potential secretion in breast milk). There could also be the Wolff-Chaikoff effect (inhibiting thyroid function).

Next, I will provide a general overview of the main antiseptics and disinfectants, as this topic is extensive. My focus is on the question: Is there really an ideal antiseptic or disinfectant? In my opinion: impossible.

For example, the antiseptic triclosan has been considered highly useful since the 1960s. As a broad-spectrum bactericide, it has shown effectiveness against methicillin-resistant Staphylococcus aureus, mycobacteria, Candida (excluding Pseudomonas aeruginosa and filamentous fungi). Its mechanism of action depends on concentration (high concentrations are bactericidal, while low concentrations are bacteriostatic, meaning they inhibit bacterial growth). Triclosan enters cells and interferes with RNA synthesis, proteins, and fatty acids. It has been widely used in products such as toothpaste, deodorants, cosmetics, plastics, and textiles. Important applications include soap concentrations at 1%, and for treating minor wounds at 0.1% to 0.2%, as well as for insect bites or acne.

I also consider it important that triclosan has a high affinity for the skin and its activity is not inhibited by organic matter. However, this characteristic can be interpreted ambiguously. From my perspective, it is beneficial for its mechanism of action but concerning if it leads people to replace handwashing with its use. This misuse could be prevalent due to its availability over the counter. It is crucial to inform users properly about its appropriate use.

Regarding adverse effects, the most common is contact dermatitis, which generally occurs when concentrations exceed 2%, or in neonatology due to irritation and potential toxicity.

Its rapid action and residual effect of up to four hours are noteworthy factors that have prompted public health alerts regarding its widespread over-the-counter use, as summarized below.

Specifically, the FDA (Food and Drug Administration) established a rule regarding triclosan, most commonly used in liquid soaps, and its counterpart, triclocarban, found in bar soaps. The rule decrees that over-the-counter products containing these substances can no longer be marketed since 2016, due to long-term exposure posing more risks than benefits, particularly with the growing issue of antibiotic resistance and the potential for adverse hormonal effects.

Additionally, the FDA has been regulating norms for other compounds, such as quaternary ammonium compounds, to establish more safety measures and ensure more information is available about whether the product packaging has undergone sterilization processes. They also recommend producing these compounds in single-use presentations. In the specific case of Chile, there was an outbreak of Serratia marcescens due to contamination of chlorhexidine, highlighting the importance of proper microbiological control.

My argument supports this decision because it will benefit public health. In my reflection, public health has become fragile due to the easy availability of many consumer products, and their widespread use should be handled more delicately to avoid contributing to antibiotic resistance. This issue is severe because bacteria are increasingly developing defenses that promote therapeutic failure.

Besides the aforementioned points, triclosan is also regulated by the European Medicines Agency and the Environmental Protection Agency, as it is considered a high-risk pesticide for both humans and the environment. This latter point is crucial, in my opinion, because contamination can affect the entire food chain.

Next, I will describe the most important aspects of commonly used clinical practice disinfectants (phenol, oxidizing agents, quaternary ammonium compounds, chlorine) and antiseptics (chlorhexidine, para-chloro-meta-xylenol, metallic compounds, and substances with both disinfectant and antiseptic properties such as iodophors, alcohol, aldehydes), as well as sterilization methods (physical and chemical, such as peracetic acid).

Regarding phenol, previously mentioned in history, it is an effective bactericide and fungicide, but it is not sporicidal. It disrupts nucleic acid formation and has additional actions such as anesthetic properties and itch reduction. Adverse effects include irritation, necrosis, and potential nervous system alterations due to high absorption.

Among oxidants, there are two main compounds: ethylene oxide and hydrogen peroxide. The former has broad-spectrum antimicrobial properties: it is germicidal at room temperature and is also considered an option for sterilization (by heat); when it chemically reacts with water and chloride, two active substances are formed: 2-chloroethanol and ethylene glycol, which act in less than two hours. Like aldehydes, it is irritating to the respiratory tract and is not recommended for use on the skin due to its toxicity and promotion of mutagenesis.

The antiseptic properties of hydrogen peroxide are more inconsistent; its mechanism of action involves the free hydroxyl radical, and when it reacts with tissue catalase, it forms oxygen with germicidal efficacy against anaerobic microorganisms. Debris and cellular remnants from wounds are eliminated thanks to this compound, particularly at concentrations of 3%. It also has another function for diluting earwax at 1.5% along with isotonic saline solution.

I believe that oxidants, not being effective against aerobic microorganisms, have a disadvantage compared to other antiseptics and disinfectants. As mentioned previously, one of the ideal characteristics is having a broad spectrum of action.

Quaternary ammonium compounds, such as benzalkonium chloride, have a spectrum that covers gram-positive bacteria more than gram-negative ones and are also found in eye drops. Their activity is not as intense in vivo as it is in vitro. They kill fungi and protozoa (Trichomonas vaginalis), and alcohol or aqueous solutions must be added for better action (benzalkonium, cetrimonium, decalonium, cetylpyridinium, etc.). They exhibit surfactant properties and irreversibly disrupt the cell membrane.

However, they have shown some difficulties compared to other compounds because their activity decreases in the presence of organic matter. Additionally, they have been shown to be less effective than chlorhexidine and iodinated compounds. Another significant disadvantage is that in the presence of soap or pus, they lose their effect, and they can form a tissue film under which microorganisms can grow.

For all the reasons mentioned, I believe that this compound, being slow-acting and absorbed by materials like plastic, rubber, and dressings (thereby decreasing its activity), does not offer an advantage over other components and should be restricted to specific cases despite not causing significant irritation.

Regarding chlorine, it is one of the most potent germicides, although its activity decreases in the presence of organic matter (and also requires a pH of around 6). Its mechanism of action is based on hydrolysis; therefore, when in the form of elemental chlorine, it can purify water by killing bacteria, viruses, fungi, protozoa, and spores. Care must be taken with its irritating and harmful effects.

For surface disinfection and wound cleaning (necrotic remains), different concentrations of sodium hypochlorite are used: 5% for surfaces and 0.5% for wounds. This leads me to consider it a quite effective compound with a broad spectrum of action and accessible for use; it is important to dilute it with a proper proportion of water and chlorine for each objective.

For example, for surface cleaning, 3.8 liters of water and only 15 ml of chlorine are used; for cleaning food cans, 18.9 liters per 240 ml; for mold removal, 3.8 liters per 240 ml.

There are three main levels of disinfection: low, intermediate, and high. The first does not allow for spore destruction and requires at least 10 minutes to exert its germicidal action, although not broad enough to cover the death of all mycobacteria, fungi, and non-lipid viruses.

Intermediate-level disinfectants do not destroy spores but are capable of inactivating vegetative bacteria; their action time is similar.

Finally, high-level disinfection can eliminate vegetative forms of microorganisms, but does not completely destroy all microorganisms as spores are resistant. It requires at least 20 minutes to be effective, potentially extending up to 10 hours, and requires the absence of organic matter to avoid deactivation.

Initial cleaning also depends on the material. Semi-critical items, which come into contact with mucous membranes or non-intact skin, should ideally already be sterile (e.g., endoscopy and anesthesia equipment). Non-critical items, which have a lower infection risk (e.g., bedding, X-ray equipment), should be cleaned with an appropriate detergent. Critical materials, which enter sterile areas of the body, must always be sterile (e.g., needles).

Among biguanides, chlorhexidine stands out as an antiseptic. Interestingly, metformin, an antidiabetic drug, is also a biguanide. They are similar molecules used for different purposes. Chlorhexidine has a broad spectrum of antiseptic action (covering gram-negative and gram-positive bacteria), although like triclosan, Pseudomonas aeruginosa is resistant.

Favorably, chlorhexidine prevents spore germination but is not sporicidal or virucidal. Like chlorine, its activity decreases in the presence of organic matter. Its rapid action destabilizes the membrane, providing strong adhesiveness; it is not significantly absorbed through the skin.

Common adverse effects include hypersensitivity and photosensitivity. Its use in mouthwashes can cause dental staining, and if it reaches the central nervous system, it can cause excitation, depression, nerve pathway blockage in the skin, and anaphylaxis.

Chlorhexidine digluconate, with a similar mechanism of action, at a 4% concentration, is used for surgical hand scrubbing and preoperative skin cleaning. At a 5% concentration with a surfactant (which reduces surface tension), it is used for treating burns or wounds (skin cleaning), body cavities (oropharyngeal, urinary, and peritoneal), and disinfecting anesthesia instruments.

Additional important actions include reducing surgical wound infections, preventing catheter infections (venous or arterial), and reducing infections associated with mechanical ventilation.

I consider these compounds less effective than aldehydes because, as aldehydes are sporicidal, they promote less bacterial proliferation. One significant error in the misuse of aldehydes is leaving materials like thermometers submerged in open containers to “maintain” disinfection, which can actually lead to contamination. Additionally, they should not come into contact with the meninges, central nervous system, or ear due to their toxicity.

Parachlorometaxylenol is a more effective bactericide than phenol, similar to cresol (mentioned later). Its concentration ranges from 0.5% to 2% to be effective, and it is useful for hand washing, acne, seborrhea, and ear infections; it can cause hypersensitivity.

These compounds can be irritating and cause allergies, so they must be used with caution. Since phenolic compounds are more potent, there is a need to be wary of the mentioned side effects. As a result, their use has recently become less frequent.

Metallic compounds depend on the element for their action in protein denaturation. For example, mercury has fragile antibacterial properties (thimerosal, merbromin), and its activity compared to other compounds does not offer significant benefits. Additionally, its adverse effects, such as severe intoxication, have led to its decreased use over time.

Silver, through its argentum ions reacting with thiol molecules, causes protein denaturation, giving it germicidal characteristics. Silver nitrate, in concentrations of 1 to 1000, is also astringent and works to eliminate warts; at 1%, it is applied to treat ophthalmia in newborns; at 0.5%, it is used for wound cleaning, preventing infections by Pseudomonas aeruginosa.

Silver sulfadiazine is not adequately absorbed (only before eschar formation). Therefore, it must be used cautiously in extensive and severe burns. A benefit is that it does not cause pain or hydroelectrolytic alterations such as hypochloremia and hyponatremia caused by silver.

In particular, zinc has a more inconsistent and catalytic antiseptic action (structural alteration). Its most widespread use is for astringent and antiperspirant purposes. It can be corrosive and irritating, and similar to silver, it can be used in ophthalmology for angular conjunctivitis at 0.25% and for cutaneous areas with impetigo, acne, and lupus at 4%.

Zinc oxide is used in creams for impetigo, varicose ulcers, psoriasis, intertrigo, eczema, among others, with a mild antiseptic effect. When combined with iron, it forms calamine, which is useful for preventing seborrhea and dandruff at 2%.

I also believe that these metallic compounds, being more commonly used in dermatology, also fulfill an aesthetic function, which is important for the patient’s quality of life, as well as the prevention of superinfections. In cases of intoxication, they can cause general discomfort, cough, fever, and chills.

Among antiseptic and disinfectant substances, iodophors have advantages due to their rapid action (starting in 30 seconds) and broad spectrum (effective against fungi, bacteria, spores, viruses such as hepatitis B and C or HIV, and protozoa). Their contraindications include hyperthyroidism, allergy, radioactive iodine therapies, and dermatitis herpetiformis.

Their mechanism of action depends on the behavior of iodine, as it can dissociate and provide iodine to the molecule, thus obtaining its germicidal property, which includes gram-positive and gram-negative bacteria, spores, cysts, viruses, fungi, and protozoa.

One of the advantages it has over chlorine is its broader spectrum of action, and it is capable of maintaining its germicidal effect regardless of the presence of organic matter (and in just 10 minutes). It is important to note that alcohol can be added to increase its germicidal potency, but this also increases its irritant action (in which case it should not be used on wounds). Additionally, this combination can make the molecule unstable, causing it to deteriorate more quickly.

From my point of view, this compound shows benefits by having more classifications (iodine solution, sodium iodide, Lugol’s solution, iodine tincture, potassium iodide, povidone-iodine, among others). At different concentrations, it will exert its action, ranging from 2.4% to 10% for greater potency, representing a superiority over other mentioned compounds. However, when iodine dries on the applied surface, its action ends. Chlorhexidine is more useful than povidone-iodine in the context of gram-positive bacteria, although the opposite is true for gram-negative bacteria.

The advantage of alcohol is that it is suitable for skin antisepsis (it must be at a minimum concentration of 70%) because it acts quickly (isopropyl alcohol is more potent than ethyl alcohol). It has no residual effect as it evaporates, but its disadvantage is its flammable properties, posing a fire risk.

Its mechanism of action involves protein precipitation, reducing bacterial surface tension with a broad-spectrum bactericidal effect (it takes just two minutes to kill 90% of microorganisms, although it does not act against spores or fungi and is an inconsistent virucide). Therefore, it is not ideal for sterilizing surgical instruments and should never be applied to open wounds as it forms clots, which allow bacterial growth.

In my opinion, it is a very useful antiseptic and disinfectant for procedures such as injections. It also has additional actions like acting as a rubefacient, preventing the formation of pressure sores in bedridden patients, and is easily accessible. To enhance its germicidal action, the skin should be slightly moist with water.

Aldehydes, such as formaldehyde and glutaraldehyde (the latter being more active), disinfect endoscopy and surgical equipment and are also useful for hemodialysis instruments made of plastic or rubber. The toxicity of aldehydes can interfere with fertility, the immune system, cause teratogenicity, cardiovascular implant calcification, gastrointestinal and respiratory injury.

One of their advantages is their broad spectrum of action: germicidal, sporicidal, virucidal. Their alkylating mechanism of action is concentration-dependent (with a greater protein precipitation effect at 20 to 30%) and at (2 to 8%) they combine amino groups to form azomethines, making cellular life unviable.

It allows for the disinfection and sterilization of endoscopic and surgical materials; however, its activity is not long-lasting, as it is lost after fourteen days, which is why it needs to be combined with stabilizers. These compounds have astringent characteristics (tissue desiccation) and are also used in hyperhidrosis (palms and soles). Among the adverse effects are irritants (more on respiratory tracts and skin).

In my opinion, this compound already represents the complexity of using antiseptics and disinfectants because more knowledge is needed about solutions that stabilize their chemical composition (phenate, polyethylene glycol, among others), which shows better germicidal activity.

After this brief review, another more practical way of classifying the spectrum of action and uses of compounds (more effective vs. inconsistent) for the elimination of microorganisms is:

• Bacteria: alcohol, hydrogen peroxide, phenolics, chlorine, iodophors, glutaraldehyde, chlorhexidine, triclosan. Inconsistent: quaternary ammonium compounds, parachlorometaxylenol.
• Mycobacteria: alcohol, hydrogen peroxide, phenolics, chlorine, chlorhexidine. Inconsistent: iodophors, parachlorometaxylenol, triclosan. Does not work: quaternary ammonium compounds.
• Bacterial spores: glutaraldehyde. Inconsistent: hydrogen peroxide, chlorine. Does not work: alcohol, phenolics, quaternary ammonium compounds, iodophors, chlorhexidine, parachlorometaxylenol, triclosan.
• Fungi: alcohol, hydrogen peroxide, phenolics, chlorine, glutaraldehyde, iodophors, chlorhexidine, parachlorometaxylenol. Inconsistent: quaternary ammonium compounds, triclosan.
• Viruses: hydrogen peroxide, chlorine, iodophors, chlorhexidine, triclosan, glutaraldehyde. Inconsistent: alcohol, phenolics, quaternary ammonium compounds, parachlorometaxylenol.

It is also worth remembering the order of resistance: gram-positive, gram-negative, mycobacteria, fungi, viruses, spores (from least to most resistant).

Concentrations (in percentage) of the compounds:

Disinfectants:

• Heat: Moist: 75–100 °C in 30 minutes
• Liquid: Glutaraldehyde: 2–3.2. Hydrogen peroxide: 3–25. Chlorine: 100 to 1000 parts per million. Alcohols: 70–95. Phenols: 0.4–5. Iodophors: 30 to 50 parts per million. Quaternary ammonium: 0.4–1.6

Antiseptics:

• Alcohols: 70–90
• Iodophors: 1–2
• Chlorhexidine: 0.5–3.75
• Triclosan: 0.3–2

Sterilizers:

• Physical: Pressurized steam: 121–132 °C. Filtration: (with high-efficiency filters: pore 0.22–0.45 micrometers). Ultraviolet radiation: 254 nanometers wavelength. Ionizing radiation: microwave or gamma (variable)
• Gas vapor: Ethylene oxide: 450–1200 ml/L; 29 to 65 °C. Hydrogen peroxide: 30, at a temperature of 55–60 °C. Gas plasma: highly ionized/hydrogen peroxide
• Chemical: Peracetic acid: 0.2. Glutaraldehyde: 2

The methods of sterilization vary according to the employed technique and the mentioned concentrations. Among the sterilizers (physical, gas vapor, and chemical), the importance lies in the fact that more common methods, such as sterilizing objects with boiling water, do not allow for the complete elimination of spores, and the effect is not sustained due to the gradual temperature change. Regarding their general mechanism of action: high temperatures have germicidal properties.

For example, compounds such as peracetic acid (chemical sterilizer), at a concentration of 0.2%, provide broad-spectrum germicidal activity as they can cause oxidation of bacterial membranes and their spores, as well as yeasts.

It acts quickly, does not leave residues that pose a serious risk, and is compatible with thermosensitive materials. Additionally, its effectiveness is not affected by the presence of organic matter. It can be applied by immersion; therefore, it is crucial to follow biosecurity measures (like the ones described below) due to its irritating exposure to skin and eyes, which is toxic (especially in solution).

Regarding chemical containment due to exposure to the aforementioned compounds (antiseptics, disinfectants, sterilizers), it is important to note that while there are over-the-counter compounds (such as alcohol) used by the general community, others are more regulated for hospital use. These regulated compounds have potential chemical toxicity in the healthcare environment, especially anesthetics, cytostatics, surgical fumes, aldehydes, hydrogen peroxide, peracetic acid, and mercury (mentioned earlier).

An example of an inhalation anesthetic is chloroform, a simple halogenated hydrocarbon, whose effect is central nervous system depression. Its use has been decreasing lately, being replaced by other compounds. Its mechanism of action includes analgesia without loss of consciousness or reflexes, hyperreflexia, delirium, excitation, glandular hypersecretion, mydriasis, cardiorespiratory irregularity, surgical anesthesia with progressive loss of reflexes and consciousness, bulbar paralysis, and ultimately respiratory arrest.

For cytostatics, such as cyclophosphamide, environmental monitoring is necessary to determine its presence in work environments and on surfaces, containers, gloves, and gowns. It can alter the phases and mechanisms of cell growth and division in its cycle and also has alkylating actions.

It has mutagenic effects, especially if used in enclosed environments. The importance of this lies in the fact that high-efficiency filters can retain particles and aerosols but not freely circulating vapors. Its levels can be detected in urine. The use of personal protective equipment, such as masks, gowns, and gloves, does not completely eliminate the possibility of detection in urine. Although it is not considered a highly irritating substance or one that causes blisters on the skin, it is controversial since cases of toxicity have been reported.

Surgical fumes, such as cresol (a derivative of phenols), are much more potent than phenol due to its three isomers. Cresol is also used as a disinfectant and bactericide but cannot be applied to plastic or rubber materials due to its high absorption. Even worse, if these materials are later applied to skin or mucosal surfaces, they can cause burns.

This example is one of many surgical fumes, which encompass a wide range of compounds such as formaldehyde, carbon monoxide, methane, phenol, benzene, ethylene, toluene, xylene, among others. These are primarily found in the smoke generated during laser surgeries.

Cresol has the ability to damage the nervous system and alter gastrointestinal, hepatic, renal, pulmonary, and skin functions. Its routes of entry include the respiratory system (causing dyspnea, tachycardia, headache) and ocular exposure (causing irritation, conjunctivitis, and vision problems). This underscores the importance of biosecurity measures to prevent exposure to harmful substances.

Regarding biosecurity measures, I consider prevention the most important tool to reduce the likelihood of risks, leading to a state of responsibility and obligations that must be adequately met to avoid accidents. From the work area to its structural characteristics, the proper application of standards, cleanliness, and the use of personal protective equipment such as gloves, gowns, caps, masks, goggles (with side protection), and specific footwear for preparation rooms are fundamental to avoiding risks.

After this summarized review and comparison of different compounds, it seems that those containing surfactants might be useful for this purpose. I believe there has been a significant impact recently, and the general population lacks the necessary knowledge base to properly use these different compounds. I feel it is my duty, including myself, because as a physician, it is my mission to adequately inform as a primary method of health prevention.

Despite the lack of a generalized consensus on the persistence of the coronavirus on surfaces (after all, the pandemic we endured serves as inspiration for writing this essay), I analyzed a study on this matter, which establishes the approximate persistence times: aluminum, latex gloves: 8 hours; steel: 48 hours; wood, glass: 4 days; paper, plastic, polyvinyl chloride, silicone, metal, ceramic, Teflon: 5 days.

My reflection on this matter emphasizes the importance of using antiseptics and disinfectants, as they can reduce infectivity. Specifically, compounds such as iodine, glutaraldehyde, hydrogen peroxide, chlorine, alcohol, and chlorhexidine are effective, according to the study.

It is important to mention that even from an economic perspective, the use of antiseptics, disinfectants, and sterilizers has an impact. Antibiotic resistance leads to prolonged hospital stays, higher mortality, and increased costs.

In the home, it is equally important to use personal protective equipment (gloves, goggles) to avoid splashes, clean first and disinfect afterward. In case someone is ill, it is better to maintain isolation, including the bathroom and utensils like cutlery and plates. It is recommended to read product labels and not mix them, ensure adequate ventilation, be careful with electronic equipment, wash hands frequently, and keep small children away (higher risk of intoxication or accidental ingestion).

To conclude, I hope I have adequately addressed the topic. Remember to keep updated with the latest scientific evidence, as microorganisms will continue to exist and the growing problem of antibiotic resistance is something we should be concerned about. Given the extensive nature of this topic, the focus should be on determining the ideal compound. In my opinion, there isn’t one because each is different, and the importance lies in knowing when to use them according to each patient’s context and situation.

Thus, resolving the doubt is about being more aware of the current state and my interest, after analyzing the compounds, is to better understand when, how, and where to use them. I believe that the approach should be prevention; avoiding factors that worsen the situation (e.g., good wound hygiene reduces the possibility of secondary infections). It would also be pointless to prescribe without a foundation (e.g., creams for burns) if the root cause of an infection is not properly controlled.

Non-pharmacological measures and patient support are crucial. Additionally, with multi-resistant microorganisms, the infection has the potential to reappear repeatedly, which can be fatal, especially in immunocompromised patients.

Excessive use of anything is harmful. I’ve seen documentaries on Discovery Home and Health channel, where people with mental health conditions like Obsessive-Compulsive Disorder exhibit extreme cleaning behaviors, disinfecting everything several times a day, which generates anxiety.

This has been a broad topic, and I believe entire books could be written about just one disinfectant. I hope this essay has been concise, encompassing history, analysis, personal knowledge, and experiences. For example, when I was eight years old, I was walking barefoot in the kitchen and broke a glass. I stepped on the shards and hurt myself. My first thought was to apply alcohol because it was the first thing I found. Luckily, my mom observed me and stopped me from applying more because it stung a lot. It was better to wash the wound with water, neutral soap, and then saline solution, letting the wound dry. Fortunately, it did not have any major complications, and I no longer see the scar.

Another anecdote at the age of 26, in the middle of clinical practice and seeing the determinants of health, no matter how much the medical staff does everything in their power; if the patient is forced to return to the environment that made them sick; for example, washing hands in resource-poor places where there is no soap and the water is not potable… Nothing is solved by simply administering antibiotics. Despite educating the population, it is part of each entity; for example, the water company.

I hope I am not too naive; in the middle of the lockdown, I thought: I hope that when the pandemic ends (or at least eases), people will continue washing their hands. It should become a habit, as well as using antiseptics and disinfectants with great care.

And at every level, because from the “simple” act of disinfecting a home; or when a baby is born; removing a wisdom tooth and so many everyday activities, such as cooking; it includes the fact that hygiene is very important for health. Above all, what I consider fundamental is knowing how to handle each of the antiseptics and disinfectants at every level. For example, from a small child learning to wash their hands to an elderly person on home dialysis who will need support.

I also think it is a very important learning process because it does not discriminate by age, gender, nationality, occupation, or many other variables. I consider all humanity to be part of hygiene, and my wish would be for much more active participation in this process. I would like to propose that these topics be taught in schools, at least the most important aspects.

I think that even if there were an ideal or perfect antiseptic or disinfectant today, perhaps tomorrow there would already be some problem (the most common and dangerous as seen) and I will not tire of saying it: antibiotic resistance.

Finally, after writing this essay, I return to my initial question: Is there really an antiseptic or disinfectant that is a panacea? I actually believe there is not; utopia is not possible. The growing problem of antibiotic resistance, misinformation, and above all: the closed mind that does not allow new discoveries. Without Lister, mortality would not have decreased. Despite people not believing in him initially, I like how the truth comes to light, and however outlandish his idea seemed at that time, I think it has revolutionized the world of Medicine, and I will always remember this milestone in science with great pride. In my opinion, a notable before and after was marked by these findings. “Those who do not know their history are doomed to repeat it.”

I have reflected, and who knows if some current medical practice might actually evolve? Anyway, if people did not believe in the existence of microorganisms before; I hope no mistake is being overlooked today that could compromise the most important thing in the world: the lives of people.

Bibliographic sources:

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