FOMITES: CHARACTERISTICS, HOW THEY ARE HANDLED AND EXAMPLES - MEDICINE - 2025

The fomites, also called vectors mechanical, inanimate or passive, are all objects or substances its structural, chemical, location or use, are able to propagate any medical condition or etiological agent. Etymologically, the word fómite comes from the Latin fōmĭtēs and means "tinder".

Tinder is any dry material capable of igniting a spark. It is important to know the characteristics of the fomites since, since they are capable of acting as vectors, their rapid identification is useful when it comes to preventing the spread of diseases and, therefore, their morbidity and mortality.

characteristics

By acting as passive and inanimate vectors, fomites have the particularity of depending on the environment in which they are found. Therefore, the location of the risk is an important factor to consider.

The cycle and gateway of the etiologic agent to the susceptible (human) host also influence the ability of an object or substance to act as a fomite.

For example, in oral fecal infections the infection enters the mouth to colonize the digestive system. Using contaminated objects such as dishes or kitchen utensils could transmit the disease.

A structure and surface suitable for transmission is necessary; that is, a surface medium stable enough for the microorganism to live for a certain time. This will also depend on the ability of the microorganism to withstand environmental conditions.

Regarding the conformation of the fomite, studies indicate that its transmissibility also depends on its surface. It has been determined that polished surfaces transmit more diseases than porous ones, since the latter absorb microorganisms, thus reducing their transmission.

Microorganisms and objects associated with transmission by fomites

Objects used in the hospital environment

The most common fomites are found in the health environment, since these objects are closely related to infectious agents due to their location.

Among these we can mention stethoscopes, ties, medical gowns, medical uniforms, catheters, injectors, endotracheal tubes, oxygen masks, and stretchers, among others.

In general, any object within a health facility can act as a fomite: from door handles to stair railings.

Some research has shown that non-porous surfaces are better transmitters of viruses and bacteria than porous surfaces, since the former do not absorb or trap pollutants and a simple contact allows their transmission.

Microorganisms

Among these microorganisms we can mention Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus viridans, Pseudomona aeuroginosa, Acinetobacter, Actinomyces, Influenza virus, enterovirus, among others.

How are they handled?

Given that they represent an important epidemiological link in the chain of disease transmission, the management of fomites is a multidisciplinary process that requires qualified and vigilant personnel from the different areas, especially in health centers, where objects could act as fomites..

- The first step is the identification of the possible vectors.

- The second step is the adequate separation of these vectors from the other objects that were not found in contact with the probable etiological agent.

- The third step is sterilization - depending on the case - of the vector in question, in order to eliminate any infectious agent from it for later use.

If it is not a vector to be used again, it is advisable to discard the object and use a new one previously sterilized.

An epidemiological measure that has been shown to prevent infections is to establish a process for surveillance and management of likely infected waste; for example, the disposal of syringes in health centers.

The use of barrier media is also important whenever contact with fomites; For example, when removing a nasogastric tube or urethrovesical tube, protection with latex gloves is necessary to avoid direct skin contact with etiological agents present in these instruments.

Examples of fomites and associated diseases

The diseases that can be spread through fomites are very varied. Those that tend to be more complicated are those that are transmitted intrahospital, especially due to the mechanism of resistance and mutation that the microorganism can undergo in said environment.

However, there is no risk of contracting pathologies through fomites only within the hospital facilities.

On a daily basis, exposure to various diseases transmitted by fomites is very common and the ignorance of what the potential spreading fomites are makes the user more careless in direct contact with them.

Among some of the diseases produced by these hospital vectors we find the following:

- Nosocomial pneumonia associated with intubation or mechanical ventilation. They are called nosocomial pneumonias, and the form of contagion is based mainly on the use of invasive devices that maintain open and direct communication with the outside world.

Likewise, viral, fungal and bacterial spread due to poor hygienic care by health personnel plays an important role when handling intubation equipment and when cleaning the patient.

- Bacteremia due to catheterization or punctures with infected syringes or catheters. This is mainly explained by poor aseptic and antiseptic techniques at the time of catheterization, which causes a direct entry route for nosocomial microorganisms.

- Urinary infections due to permanent or recurrent urethrovesical catheterization with infected tubes. This occurs in cases of underwear that has not been washed and changed in the days of stay, poor hygiene of the genitals or mishandling of the probing implements before placement (contact with the bed, with the doctor's clothes).

Fomites in the daily environment

The mechanism of spread / infection is basically the same with any form of our daily environment.

If someone with a respiratory disease sneezes or coughs without covering them with a tissue, and does not wash their hands afterwards, they will spread the microorganisms that cause their disease to all the surfaces with which they have contact from that moment on.

Subsequently, anyone who comes into contact with these surfaces and then puts their hands to their mouth or nose, will become infected with the microorganism.

Among the fomites that can be found in the daily environment, the following stand out:

- Door handles and keys.

- Pens, pencils, staplers or any stationery.

- Public transport.

- Handrail.

Treatment of diseases transmissible by fomites

In fomite infections, treatment will be directed to the causative agent of the clinical picture.

Nosocomial pneumonia

The antibiotics of choice will be glycopeptides, such as vancomycin; or the cabapenemics, such as imipenem.

Uterine tract infections

The antibiotics of choice will be aminoglycosides, such as amikacin or gentamicin.

Bacteremia secondary to catheterization

The antibiotics of choice will be penicillins against coagulase negative Staphylococcus, such as intravenous cloxacillin.

Epidemiological chain

It is important to highlight that for a disease to affect an individual, the three elements of the ecological triad must be present: the host, the environment and the etiological agent.

However, it is also vitally important that for this to happen there must be an agent, vector or organism that puts these three elements in contact.

This is the case of fomites; therefore, for disease prevention and health promotion it is necessary to eradicate and control them to reduce the incidence of diseases.

References

1. Hospital Infections. Recovered from: edu.uy
2. The tie as a nosocomial fomite in health personnel. Recovered from: com
3. Bacterial enteric pathogens. Recovered from: uba.ar
4. Fomites Management to minimize infection. Recovered from: iastate.edu
5. Fomites etymology. Recovered from: dicciomed.usal.es