The fomites, Also called mechanical, inanimate or passive vectors, they are all those objects or substances that, due to their structural, chemical, location or use characteristics, are capable of spreading some type of pathology or etiological agent. Etymologically, the word fómite comes from Latin fōmĭtēs y 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..
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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 risk is an important factor to consider..
The cycle and gateway of the etiological agent to the susceptible host (human) 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. The use of objects such as contaminated 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 more polished surfaces transmit more diseases than porous ones, since the latter absorb microorganisms, thus reducing their transmission..
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 found inside a health institution can act as a fomite: from door handles to stair handrails.
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.
Within these microorganisms we can mention the Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Viridans streptococcus, Pseudomonas aeuroginosa, Acinetobacter, Actinomyces, Influenza virus, enterovirus, among others.
Since 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 etiologic 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 that must 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 the 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..
The diseases that can be spread through fomites are very varied. Those that tend to become 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.
In the day to day, exposure to various diseases transmitted by fomites is very common and the ignorance of which are the potential spreading fomites 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 pneumonia, and the form of contagion is mainly based on the use of invasive devices that maintain open and direct communication with the outside world..
Likewise, viral, fungal and bacterial dissemination due to poor hygienic care by health personnel plays an important role when there is manipulation of intubation equipment and when cleaning the patient..
- Bacteremias from 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 tract infections from permanent or recurrent urethrovesical catheterizations with infected catheters. This occurs in cases of underwear that has not been washed and changed in the days of stay, poor hygiene of the genitals or poor handling of probing implements before placement (contact with the bed, with the doctor's clothes).
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.
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.
- Railing.
In fomite infections, treatment will be directed to the causative agent of the clinical picture..
The antibiotics of choice will be glycopeptides, such as vancomycin; or cabapenems, such as imipenem.
The antibiotics of choice will be aminoglycosides, such as amikacin or gentamicin.
The antibiotics of choice will be penicillins against coagulase negative Staphylococcus, such as intravenous cloxacillin..
It is important to note 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 the prevention of diseases and the promotion of health, it is necessary to eradicate and control them to reduce the incidence of diseases.
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