The wide and increasing range of Legionella diseases, as well as the isolation and identification of species and serogroups of this bacterium from environmental sources and patients, indicates the global spread of Legionella species in different countries.
Numerous reports of the epidemic and sporadic occurrence of Legionnaires' disease and its resulting deaths have attracted the attention of researchers and specialists in lung and respiratory diseases, infectious diseases, microbiology, immunology, environment, genetics, etc.(12)
Early diagnosis of Legionellosis and epidemiological conditions in the hospital is necessary not only for correct and effective treatment but also to control and prevent the subsequent onset of the disease. It seems that due to the high mortality rate of Legionella disease, more effective measures should be taken to prevent the spread of Legionella species from the hospital environment to patients susceptible to infection. (7, 12).
Legionella infections in immunocompromised individuals, corticosteroid recipients, organ transplants, the elderly and children, alcohol and drug addicts, smokers, patients with diabetes mellitus, underlying diseases, chronic obstructive pulmonary disease, intubation, intubation and it poses a serious threat to heart patients more than anyone else.
Legionella alone causes a high percentage of nosocomial pneumonia. This bacterium causes 1 to 40% of hospital-acquired pneumonia. The mortality rate in legionellosis is 5–30%. About 5% of cases of Legionnaires' disease are reported from hospitals. (26)
Legionella pneumophila was the cause of 3.8% of fatal cases of nosocomial pneumonia. Bacteria of the Legionella genus are isolated from natural water sources, public water reservoirs, water pipes, and even bath showers.
Because various factors are effective in the growth and pathogenicity of Legionella bacteria, the factors affecting the growth and survival of bacteria can be largely identified and their findings can be used to design an appropriate control method. (!2,7,26)
Today, various methods to control Legionella in hospital and community aquatic environments are being studied and performed. Therefore, identifying pathogenic strains in that area can provide specific ideas for the use of effective and efficient disinfectants to control Legionella.
In a hospital population, there are always patients who are susceptible to infection and are at high risk for Legionella. Water is one of the common sources of Legionella transmission in hospitalized patients.
Early diagnosis of legionellosis and epidemiological conditions in the hospital is necessary not only for correct and effective treatment but also to control and prevent the subsequent onset of the disease. It seems that due to the high mortality rate of Legionella disease, more effective measures should be taken to prevent the spread of Legionella species from the hospital environment to patients susceptible to infection. (12)
Many types of research have been done using different methods in removing Legionella from water, some of which are mentioned, and the advantages and disadvantages of this research are examined.
Loret et al. reported in 2005 studying a variety of disinfectants such as ozone, chlorine dioxide, chlorine, monochloramine, and copper and silver ionization to remove amoebae and plankton. Marches et al. Chlorine oxide was used to remove Legionella bacteria (24). Sodium hypochlorite was used to remove Legionella from water, which of course has a higher oxidation rate than other disinfectants and affects a wide range of microorganisms, but has disadvantages such as carcinogenicity and side effects (26).
Other methods used to remove Legionella bacteria were photocatalytic oxidation (using 365 nm UV) with titanium dioxide. Chen et al. used the heat shock method in 2005.
In a 2008 study by Cheng et al., They used the ionization process of copper and silver as a disinfectant to remove Legionella pneumophila. This procedure took 4 to 7 months and studies have shown that this method is effective in the short term and the pollution has not been eliminated (27).
Diamond electrode electrolysis is used to remove and inactivate Legionella bacteria (28).
In general, the advantages of this research over other research in this field are as Long-term bactericidal stability of George Fischer tube, do not use chemicals, No carcinogenicity, No corrosion of pipes, No side effects, No need for preparation, Low investment cost.
The results showed that George Fischer pipes and fittings are much less contaminated and only out of 34 samples related to the George Fischer pipe and fittings system, 2 samples (samples number (20 and 10) showed contamination with Legionella, based on which it can be said that the pipe and George Fischer connections in more than 95% of the growth of Legionella pneumophila in water, which showed the role and impact of using this system in controlling infections associated with this bacterium, which causes very acute and important problems in the health system, especially in Medical centers, hotels and other administrative, commercial and recreational centers, so that in case of contact with this bacterium and infection and lack of proper treatment can cause the death of infected people.
The results showed that the use of Ray ho pipe and fittings system has higher contamination than George Fischer pipe and fittings system, so that out of 22 samples collected from Ray ho pipe and fittings, 12 samples showed positive and Legionella contamination. These results showed that Ray ho pipes and fittings in more than 55% of Legionella contamination, which confirms the superiority of George Fischer pipes and fittings over Ray ho pipes and fittings.
Examination of the results in terms of Legionella bacterial density in these systems also shows that George Fischer pipes and fittings are not only less contaminated but also in terms of contamination density than Ray ho pipes and fittings and metal pipes. As the system in George Fischer pipes and fittings, only 2 samples with 2 bacteria per liter of water have been observed, while in Ray ho and metal pipes, the probability of contamination and bacterial density is high, which indicates a good ability George Fischer pipes and fittings are in control of Legionella and the inability of these pipes to control Legionella.
The results showed that the average bacterial density in Ray ho pipe and fittings was more than twice that of George Fischer pipe and fittings, so that the range of changes in Legionella bacterial density in Ray ho pipe and fittings was in the range of 2–16 colonies per liter, while this density in pipe George Fischer's connections are only 2 bacteria per liter, which is even lower than the recommended standards for Legionella density in the piping system of developed countries. Comparison of Legionella density in metal pipes also shows that these pipes are not comparable to George Fischer pipes in terms of both probabilities of contamination and density so that in these pipes, 3 out of 5 samples had contamination in which bacterial density. On average, there are more than 43 colonies per liter of water.
The presence of positive results and densities of Legionella bacteria in water samples and their negation in PCR method based on mip gene indicates the presence of contaminants in water that contact with the pipe fittings of George Fischer has prevented its growth or caused their destruction. The only evidence of the presence of Legionella pneumophila DNA in water, which confirms the effect of George Fischer pipes and fittings in controlling and removing Legionella, which shows that this system is suitable for use in the plumbing of medical centers, hotels, leisure centers, etc. Because in such centers, people are more likely to be exposed to acquired lung pneumonia, which not only has a high cost of treatment but also causes death if not treated properly. The results showed that 28 of the 34 samples of George Fischer pipes and fittings in the culture method were negative but based on positive mip gene, which indicates the absence of culturable bacteria but also shows the presence of Legionella pneumophila DNA as a dangerous species of Legionella in water and ability the effect of the tube on the control of Legionella. This is the case for 6 out of 22 Ray ho pipes and fittings.