Introduction
The on the way investigations recently done in the hospital Umberto 1° of Rome for suspicious legionellae infection, the investigation to for the presence of colonies in the reservoirs of the trains, the temporary closing of the Holiday Inn Venice East in Venice are alone some of the most recent episodes that have bossily brought the attention of the public opinion on these thematic ones raising, accordingly control's level from the competent authorities. An effectiveness strategy of prevention is, todayr, essential with the purpose to avoid that an episode also only of suspicious contamination turns not only into an assumption of responsibility under the civil profile and penalty, but also in a true boomerang to level of image. The problem of the contamination of the waters, in reality, it doesn't have recent origins: already in the scientific communications of the years 60 and the first years 70 are recorded the presence of a pathogen agent , then not yet well identified, able to induce some serious pulmonary pathologies with important clinical pictures and characterized by an elevated mortality. Only following the contagion of over 200 people with about thirty deaths in Belview Stratford Hotel of Philadelfia of 1976 and following research, nevertheless, it came to individualize a gram negative bacterium as responsible of the epidemic of pneumonia.. Such new pathogen agent was the Legionella pneumophila, that places in the panorama of the etiologic agents of class II, in degree, that is. to also produce some deadly epidemics beginning from sources of contagion specifications without the possibility of propagation through the relationships interpersonali (from individual to individual).
The "classification", and the name of the bacterium, especially derives really from the epidemic event that has brought to its identification, since the guests infected of the Belwiev Hotel were members of an association of soldiers of fortune called in the common slang "Legionaries." An analysis to back of other serious epidemic events, of doubtful origin, has confirmed that the bacterium would already in the past, be been able to reach the 1976 results. The problem "Legionella" has been silent and practically nonexistent for the public opinion, despite its importance, up to be revealed from other epidemic phenomenons with characteristics similar: the SARS before and the avian influence then. The situation of general alarm created by these pathologies, in fact, has conducted to a greater control and to a specific attention really to the etiologic origin of the suspicious pneumonias.
The result of the search has been the identification of the urinary antigen of the bacterium, happened few years a go, that allows to individualize in a few hours in the patient the presence of Legionella pneumophila of group 1 (cause of the 80/85% of the hospitalized cases).
This finishing line is revealed particularly important is because it avoids the necessity to perform invasive mesaures (as the biopsy) both because it allows to also identify the bacterium in the cases in which the subject is submitted to a heavy antibiotic therapy to ample spectrum (which has, as first effect, that to falsely make negative the microbiologic tests, even if conducted on the expectorated ones or on the broncolavaggis).
The search of the urinary antigen, is easily besides a repeatable examination, rapid and I specify.
Limit of the test is that it allows to identify only the log of the sgroup (that more dangerous) among those potentially implicated, escaping the possibility to identify the least virulent subgroups able to induce some syndromes of smaller gravity as the fever of Pontiac.
This easily explains not otherwise also the affirmations of underevaluation of the problem .

 

 

The normative horizon
The gravity of the clinical picture and the rate of mortality ( can reach 10-15%) it mostly sets the bacterium among those dangerous for the human health (you are enough to remember the epidemic of legionellosi had in the summer of 2005 in Canada with over 80 infected people and 16 deaths) and accordingly all the dispositions to it inherent they are substantially directed in an optics of prevention of the events. Under the juridical profile tightly, in the Italian panorama, the problem in object reenters among the thematic ones disciplined inside the Legislative Decree of the Government n. 626 of September 19 th 1994, to all known because it faces in detailed way the problem list of the safety of the health in the environments of job.
The norm, in fact, recalls the biological risk in the enclosure XI - List of the biological agents.

 

 

The law, nevertheless, limits to recognize a substantial responsibility of the giver whereas in presence of a risk he doesn't have provided to perform all the necessary shrewdness to avoid into effect that from it you derive a harmful event for the health.
There is not, that is, some indication on the formalities with which this guardianship has to be insured.. The technical-scientific references with which to operate. are, instead, contained in some lguidelines approved and sent forth by the Lecture Permanent State-regions and Autonomous Provinces with the support Superior institute of the Health and the EWGLI (European Worcking Group for Legionella Infection) that they represent
From 2000 to today such technical documents, repeatedly adjourned, have had as live privileged area of study and application the hotel structures (receptive structures) of various type and the thermal structures.
They, nevertheless, also represents however the documents of reference for all the other structures that entertain community (hospitals, , jails, barrackses etc…). From the 2000 guideline it is, possible to underline what factors can make the individuals more susceptible than contagion as brought in the box/fig. 1.
In substance it is necessary to effect an analysis of the environment and the fittingses to verify if are under the conditions in which the possible presence of the bacterium can bring to its proliferation and following danger (real) for the users and the workers that are found to operate or to frequent such structures.

Such conditions are
-water's presence to an inclusive temperature among 25 and 55°C
-the possibility in that such water is nebulized depart particles so small to reach the low respiratory tract.
For how much it concerns the first element it is recorded an increase of risk in presence of stagnations or (worse) of circuits in which water suffers a continuous thermal treatment with a range of temperature that reenters in stable way inside that allows the growth of the bacterium as optimal conditions.
Typical example are the systems of distribution with recircle of the sanitary warm water.
The growth of colonies is also favorite in presence of biofilm and oxides and metallic ions, normal presence in all the types of fittingses in which is managed and distributed of the sanitary warm water.
The presence of colonies of "Legionella pneumophila" in the fittingses it concretely becomes dangerous for the health only in the hypothesis in which water is sprinkled, or nebulized, in how much, as already says, the bacterium can expound the own characteristic alone and exclusively if it has the possibility to come at the low respiratory tract and this is normally possible solo if water's particles bearers of the bacterium have a dimension equal or smaller of 5µm. From here the direct involvement of all the receptive structures (hotels, hospitals, houses of refuge etc…). in which the people use warm water

Operational procedures
In passed the most frequent strategy has been that to effect only interventions of reclamation following reports or cases acclaimed of legionellae disease. In reality, today, this operational modality made only following emergencies (if also still very diffused) it doesn't appear more winning since, as is underlined, it has risen up the threshold of attention. Therefore, more and more frequent controls are performed from the authorities competent faces to verify that near the structures to risk there is in to be the necessary measures of prevention and during which, collectings of champions of water are often, effected from also to submit to analysis. Where the laboratory tests underline the presence of the bacterium, also in absence of reports, is often reached the temporary closing of the structure with the damages that can derive from this. With these premises it is opportune in the management of a structure, to know and to also face these aspects. In first place it is necessary to wonder if in own structure there is the possibility of colonies of legionellae in own fittingses.
The guide lines foresee, in this sense, an analysis of the based risk on the examination deepened of the schemes of the present technological fittingses of the characteristics of use and the typology of users/ workers.
This must always done since, as it is logical, it is possible to exclude the presence of the alone risk after having effected a specific test.

 

Such analysis of the risk has to regularly be repeated, at the most every two years or, as every ,is obvious whenever is modified some parameters that can influence the conditions (for example a change of the fittingses or the insertion of new parts, equipments or technologies). It underlines the demand to make to the map of the risks to experienced professionals that unite to the technical competences in subject of implant technologies, specific notions in relationship to verify some risk
Such choice is fundamental not only to be able to identify in corrected way the possible methodologies of intervention, but for the individualization of the subject guarantor in civil center and penalty of the safety, since, as for other aspects of the "626" in lack of specific nominations, the burden directly reverts on the person responsible of the structure An effective solution to make sure the necessary competences is the creation of a team to hoc.. The document of evaluation of the risk with the programmatic sequence (lilt and periodicity) of the operations to be performed in the lguide lines has called "Register of the interventions." In it the nominative of the manager is formalized (also responsible) of the system of prevention and is individualized, besides, to whom the burden competes to effect the programmed operations.
The "register of the interventions", in fact, it is not a mere register of what is is performed, but a document that has to underline a complex system that contains:
uan accurate and competent analysis of the risk
uan evaluation of the phases to the search of the critical areas,
uthe individualization of the parameter or the condition/operation that set the critical phases under control,
uthe layout of a program of such operations, of the procedures that allow the correct execution of it through an exhaustive and precise description, of the registration cards that attest the execution of it with the individualization of the operator and the indication of an inspector that confirms the realization of it.
For the employees it is easily identifiable in the signalled contents the realization of a system HACCP (diffused in the sector agrriculture and food) or better a system of prevention, control and reduction of the dangers realized in the respect of the principles founding i the quoted system. The guide lines fix, besides, of the different levels of contamination of the fittingses conferring to the various situations one "dangerousness" formal. Such classification, nevertheless, is to consider only on the practical plan indicative since it comes in many cases denied by the verification of the cases of legionellae disease post under investigation from the magistracy The level of dangerousness, as suitable in the guide lines, in fact, it founds him on the hypothesis that the presence of the bacterium both "statics" and apparently constant in that point of the plant.

 

In reality, as it is easily understandble, the bacterias have one dynamics of theirs population that brings them (as all the living organisms) to grow to present of favorable conditions transforming a situation of density lower part initial levels in an indeed dangerous contamination of the water. In the fittingses, for instance, areas or parts of them can be in which this phenomenon of exchange doesn't happen (typically in the side branches, detached place, that bring the warm water to the uses).
These pipes become, to all the effects of the incubation place in which the bacterium can proliferate in absence of phenomenons hindered up to reach those concentrations that cannot only constitute a real danger for the susceptible subjects but also for the individuals endowed with normal immunocompetence.
To forehead of this there are other phenomenons as, for instance, the flux parameneter of the fittingses that removes and it dilutes the circulating quota of bacterias because of the entry of clean water and the elimination of a peer volume of contaminated water through the uses. It can happen then, as is in effects it happened,l'implication in signalings of cases of legionellae disease, of structures that have introduced in the controls performed to back of the low titles of contamination
This, obviously, in the case the individualized source was unique and without other possibilities of origins alternatives of contagion.
In reality the obligation emerges to have the fittingses "clean" that is at least under the threshold of measuring of the presence of the bacterium, thing that implicitly it allows to affirm that the plant, if it is not in absolute sense exempted by the presence of the bacterium it has, however, a presence that in any way can arouse a risk for the workers /users.
Normally the sensibility of the tests various from 20 to 80-100 ufc/ls.

Application problem list
In relationship to how much delineated it is evident that every structure at risk must to set in to be a suitable program of management of the risk "legionellae" based
uprocedures of prevention
utreatments of periodic reclamation
usystems of maintenance
The guide line point out a series of procedures that have to be mails in to be in the ordinary management of the structure.
Of the suitable operations some are indeed important in relationship to the principle of precaution as the periodic disinfection of the reservoirs), and others instead, in reality alone of the indications of operations of cleaning.
These last, in effects, have to do very fieuw with the real reduction of the risk: should be thought,for example, to the cleaning of the alone atomizers of the showers whose risk of colonization is very contained because they are practically dry for the most greater part of the time and they have an extremely laughable residual volume to comparison of the volume of the pipe of feeding that brings the water from the uppercut to the atomizer.
There are contrarily some points where indeed the risk that occurs a colonization and of a bacterial growth to dangerous values is very high. The pipings, are for instance a very probable center of microbial proliferation, and it is therefore essential that the operations of reclamation include an accurate disinfection of the whole plant, "point of detach" and inclusive side branches, and not only of some terminal parts of the same.
An effective intervention, therefore, asks for a careful and accurate study of the structure and the operation of the plant to treat departing from the presupposition that every case is a reality to itself.
Different modalities or methods exist for effecting the operations of reclamation to periodically effect.
In general, to today, the methodologies most used, in operation of the experiences acquired, founds upon the application of based systems on the dioxide of chlorine, on metallic ions, on the thermal shock, on the ipercloration pure and simple, etc.
It doesn't exist, however, a standard recipe, since, as it is more times underlined, every reality must be studied in its oneness
Till now all the issued technical and juridical documents are essentially planned instead in the logic of the, "absolute care" able to assure the results of zero resetting or strong reduction of the bacterial counts in every condition and situation solutions look for you through the construction in the laboratory of models "experimental" that, in effects, they absolutely are not representative of the realities of the plant.
In any lguidelines, for instance, is made reference to the problem list produced by the presence of incrostation and stratifications of carbonate of kick and magnesium that in reality they are one of the most greater difficulties on the operative plain (see photo n. 1), but in the lguidelines this problem seem to be relegated to "detail" secondary to resolve only when possible.
For a real efficacyof the treatments, importance is underlined to individualize in the fittingses the presence of dead branches or non subject portions of plant to continuous circulation of the water (by - pass, fallen uses in disuse, etc.) but it is forgotten that inside and under the calcareous incrostaztons it exists of fact a portion of space that constitutes a consistent "dead branch."
Such element is not appraisable and is of difficulty if not impossible treatment when for the reclamation the chemical shock is used from only ipercloration to today considered the best remedy for its characteristics of absolute efficiency . This disinfectant and all of its derived principals have, in fact, the characteristic to strongly be active to pH slightly acids (5,8 - 6,5) and showing a discreet activity on the biofilm also is not able to penetrate in depth in the compact layers of limestone with the consequence that iare not trated the knapsacks of contamination that are found or under or inside. With this solution is not normally reached the knapsacks of ricontamination that can be found to their inside with this solution derives or under of them.
This incapability of penetration could be the principal cause of the raisings of the levels of L. pneumophila ascertained after the interventions of ipercloration shock awkwardly done or in way not controlled and checked in continuous.
In conclusion the experience has shown that the treatments with chemical shock from ipercloration are shown effective to remove the bacterias in the circulating flow of sanitary water, but to the success of the moment it is thick happenned an immediate and thick ricolonization of the plant, to greater titles also of those before the treatment (within 48/72 hours).
The growth accelerated following the treatment is probably due to the mobilization of materials, organic and not, present in the plant over that to the creation of metallic oxides.
The lowering of the temperature of the water must be signalled to besides optimal levels for the bacterium, of the plant that to end treatment has to be "emptied" and polished up by the chemical agent before being put again in service.
How has benn signalled, for the application of reclamation is often asked when, following signalings of an involvement in a case of legionellae disease and from the following positive microbiological test, the possibility is confirmed (not the certainty) that the contagion has happened inside the structure.
There is therefore, usually, in these cases, already in to be a syndical ordinance of adoption and application of the contained precautions in the more times quoted guidelines.
In reality the obligation to respect the contents of the guidelines it is a necessary condition, but not enough to resolve in concrete the problem.
On the market different realities that offer the service of reclamation of the fittingses of sanitary warm water exist.
To be able to direct in a correct way is necessary to verify that the looked out upon solutions follow a methodology that satisfies the followings conditions:
u assure the attainment and the maintenance of the effective levels of the disinfectant in all the points of the plant
u is repeatable
uhas a least impact on the plant
uis realizable in compatible times with the hotel activity
u understands a verification of the effectiveness or is approved from the organs of control
To really resolve the problem is' important to submit , therefore, to suppliers that boast a vast casuistry in the subject and that has set in protocols that not only guarantee the zero resetting of the bacterial position but also the disappearance of every trace of Legionella pneumophila
Only the appeal to an intervention of reclamation effected in ugency by specialized personnel with the scrupulous application of a well formalized protocol has allowed to get the microbiological negativity (in twelve days) and the negativity in PCR (in four hours) that has allowed the Holiday Inn Venice East, closed for ordinance of the sanitary authority, to reopen the hotel structure within 36 hours from the moment of application of intervention. Must be underlined that this has been the first case in which the results of the PCR have been considered valid to testify the effectiveness of the reclamation effected on the plant.
How is mentioned, the periodic treatments must be insert in an ampler management of the risk of contamination that also foresees the use of systems of maintenance adopted to precautionary purpose.
In substance, usually they are treatments in, continuous of the water of feeding of the fittingses, characterized by a low dosing of one or more disinfectant principles to reduce the possibility of growth of the bacterium during the following phases.
The criterion is, however, that to maintain the characteristics of potability as foreseen by the dictated of the D. Lgs. 31/2001.
As for the treatments of reclamation so also for the systems of maintenance there are different solutions. on the market.
Some are founded on dosing of chemical agent as ions silver and copper or from dioxide of chlorine.
The options with the dioxide of chlorine and silver ions and electrolysis copper have both as side effect that are methods complex and a lot of expensive.
The method that uses the silver ions and electrolysis copper, nevertheless, has as possible alternative the silver dosing and peroxide of hydrogen (oxygenated water) that it reduces to a tenth is the cost of purchase that especially that of management.
A dosing of these active principles, nevertheless, could bring to be revealed in the time problems of possible drug resistance in Legionella pnumophila with all the problems that this could cause.
And' therefore important to require to the society that furnishes the system the guarantee that these products are not used with the purpose to guarantee to the necessity of it the effectiveness on the most resistant fetterses during the treatments of reclamation effected with the same active principles.

 

Conclusions
To set under control the "risk legionella" it requires, today, a deepened knowledge both of the consequences in terms of responsibility both of the most correct strategies to be applied for reducing the possibilities of contagion to acceptable levels to human beings.
To the persons responsible of the structure, in fact, above all if they operate in a sanitary context, it is not more granted than to ignore the problem or to manage only it in situation of emergency and that is in front of episodes of acclaimed contagions or only suspected also. The careful analysis of the risks, the correct estate of the "Register of the interventions", the realization of treatments of reclamation programmed and the installation of efficient systems of maintenance they constitute, by now, a run forced for all those people who desire to face in aware way the biological risk produced by this bacterium. Since, nevertheless, the possible solutions are a lot of and on the different choices they operate manifold factors it is opportune that the person responsible, in lack of resources human inside specifications (hardly available), makes him place side by side from reality that they furnish suitable guarantees in terms of matured experience and effectiveness in the results.
And' this, in reality, the most efficient way to guarantee a defense of other people's health as it is also logical without considering that is imposed moreover by the actual law. The realization of a valid system of prevention of the legionella risk becomes, therefore, the only valid tool able to protect the structure from the damages that could rise following a report for suspicious legionellosi.

Prof. Maurizio Podico
Secretary of the National Council of the Biologists
mauriziopodico@libero.it

Dr. Michele Checchin
Responsible Environment and Safety Unindustria
Padua - Italy

Dr. Massimo Sbacchi and Dr. Adriano Velata
Experienced of the procedures of prevention of the risk
and reclamation of the legionella fittingses
Milan - Italy