 The limits of conventional disinfection techniques
The hygiene policy observed in institutions visited by the public has been considerably improved and reinforced. It remains regrettably true, however, that disinfection still falls short of the level of excellence that each hospital patient and each health professional has the right to expect.
Until now, there has been no procedure offering totally effective disinfection of all spaces and surfaces, and zones have often been left untreated, opening the door to nosocomial infections. After any traditional disinfection of premises, it was therefore not unusual to find that certain bacteria had survived in the vicinity of the patient, such as:
- Gram-negative bacilli (Escherichia coli, Pseudomonas aeruginosa),
- Gram-positive bacilli (Staphylococcus aureus),
- Various micro-organisms (anaerobes, mycobacteriae, fungi, parasites, viruses etc.).
This observation demonstrates the limits of conventional disinfection techniques.
Disinfection techniques currently used in hospitals are based on two protective principles :
- Manual disinfection using alcohol wipes and sprays : two subjective approaches
These methods treat only those zones that are easily accessible and leave the choice of surfaces to the operator’s subjective idea of risk-assessment. Any reservoirs of germs not disinfected can recontaminate the disinfected surfaces (through sporulation and dissemination). Water-based sprays also produce an umbrella effect, which considerably reduces both diffusion and efficiency. As they settle, the droplets leave vast zones untouched by the disinfectant, even on directly exposed surfaces.
Moreover, a zone regarded as being nonaccessible by an operator, and then less or not treated, contains also germs representing a risk for the patient.
- Disinfection by nebulisation : a toxic and hard to apply method
Nebulisation is principally used for disinfecting the air. It is generally done with products that are corrosive to the skin and/or toxic when inhaled. Each room therefore needs to be sealed beforehand, requiring a considerable time for preparation.
The atomizing generates a saturation of the air, through vaporization of the "gas" type (particles of 0,5µ with 1µ). So the operation of disinfection mobilizes a lot of human and material means.
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