Search

Various techniques have been developed in recent years for the molecular typing of microorganisms. Remains particularly difficult to isolate clinical strains for the low availability of cases and even more problematic matching clinical / environmental strains. We investigated 13 strains of Legionella pneumophila of clinical and environmental origin, isolated in 3 Health Facilities in Milan (2003-2006), using three molecular typing methods: Pulse-Field Gel Electrophoresis, Amplified Fragment Length Polymorphism and Sequence-Based Typing. PFGE and AFLP showed the correlation between a clinical case with only one of the environmental isolates taken from the places frequented by the patient, demonstrating with certainty the nosocomial origin of the case and identifying the source of infection in the shower water (Clin. 1 and Env. 1N). Two clinical samples from patients admitted to different wards presented an identical profile, which suggests that the nosocomial origin assumed an epidemic form, even without having isolated the environmental strain due to the absence of samples drawn during the period under consideration (Clin. 2 and 3). Finally, the comparison between the isolated environmental strains demonstrated a heterogeneous presence of strains, not correlated to each other although they belong to the same serum-group, having profiles that are clearly different regarding number and position of bands (Env. 2 and 4). The profile 2,10,18,10,1,1 had never been isolated and typed previously in Europe. The SBT has proved a better technique for reproducibility and interpretation of results than PFGE and AFLP To complete studies on SBT method, now considered gold standard, is currently being the EWGLI 5th Proficiency Panel, in which we are actively involved with the genotyping of five strains according to the latest version of the protocol (4.1).

In an university hospital of about 900 beds, a clinical surveillance was activated to detect cases of Legionnaires' disease in patients affected by community and/or nosocomial-acquired pneumonia. In the hospital Legionella spp was detected in the hot water distribution system and various disinfecting and control procedures were adopted to reduce contamination. Contemporary, the clinical surveillance began with the systematic detection of Legionella urinary antigen among recovered pneumonia, seroconversion as confirmation test and the collection of respiratory secretions or other biological materials to isolate the microorganism in patients positive to the urinary antigen. From September 2003 to May 2005, 486 pneumonia were followed, 98 of which considered of nosocomial origin. In total, 15 cases of community-acquired Legionnaires' disease were detected by the urinary test, whereas no cases of nosocomial origin were found. The characteristics of the detected cases are described in comparison with the other pneumonia and the surveillance cost was evaluated. The systematic clinical surveillance for Legionella infections is feasible with limit costs, allows to detect community-acquired cases otherwise unknown and to ascertain the absence/presence of nosocomial-acquired pneumonia, irrespective of the environment contamination.

The author goes over the steps that have marked the individuation and knowledge of Legionellosis, from the point of view of Public Health. She stresses the importance of surveillance and discusses the disease precautionary measures and sanitary control.

Travel for business or tourism has become increasingly common in the age we live in. The great volume of national and international traffic and the speed of transportation are inevitably linked to a possible increased risk of acquiring certain illnesses such as Legionellosis, which, in fact, has shown a consistently increased incidence in recent years. In this paper, a brief introduction regarding the etiology and clinical and epidemiological characteristics of the disease, is followed by recent national and international data regarding its diffusion and guidelines for its prevention and control.

The frequent occurrence of Legionnaires' disease outbreaks in many countries, including Italy, highlights the importance of epidemiological investigations on this disease. For this purpose, an active surveillance programme of pneumonia patients was carried out in a large hospital in Apulia (Italy) from March 2001 to December 2003. A total of 612 patients were tested for Legionella pneumophila infection by urinary antigen detection and evaluation of antibodies titre. Culture of respiratory specimens was performed on 117 patients. Thirty-seven patients (6%) tested positive for legionellosis: 10 resulted nosocomial cases and 27 as community-acquired. Only 9 cases di Legionella pneumophila infection were reported from Apulia to the routine surveillance system between 1996 and 2000. The results of our study denote the level of underestimation of this disease in Apulia.

An outbreak of nosocomial legionnaires' disease in a hospital of Northern Italy is described, together with the epidemiological survey and the control measures adopted. Two patients developed Legionella pneumophila (serogroup 1) pneumonia, one (immunodepressed) died. The Task Group organised by the Health Service excluded other previous nosocomial infections, and made controls on patients and personnel of at risk units (all negative). An intensive programme of environmental sampling and educational activities on personnel have been carried out. The environmental surveillance revealed that the centralised hot water distribution system of the hospital was colonised with Legionella. Shock heating and hyperchlorination of water were applied, which reduced the number of contaminated sites short term, but recolonisation took place two months later. We underline the difficulties encountered to control Legionella by active surveillance of water quality; once the system is contamined, Legionella eradication may be difficult and expensive, and cases of hospital-acquired legionnaieres' disease are likely to occur.

Legionella infection was recognized as a cause of human disease in 1976, following the occurrence of an epidemic at Bellevue Stratford Hotel, Philadelphia, USA. In the subsequent years, various cases, both sporadic and epidemical, have been reported worldwide. In Italy, the first reports date from 1980. The compulsory notification of the disease was established in February 1983, and a few months later a National Surveillance Programme started operating at the Istituto Superiore di Sanità, Rome. Up to June 30, 1990, 542 confirmed cases of legionellosis were reported. For 249 of them, data of clinical and epidemiological significance are available. The incidence of the disease is higher in males (76% of total cases) and 51.5% of the patients are aged more than 50 years. During the clinical course, the occurrence of hepatic and/or renal dysfunction, cough, dyspnoea, diarrhoea and confusion was documented in a significant proportion of patients. The fatality rate was 12.4%. The disease occurred both sporadically and epidemically. Namely, clusters and outbreaks were detected all over the country, accounting for a total of 97 cases. Hospital patients should be regarded as an important category at risk for infection. The occurrence is also frequent among travellers and tourists, because of the stressing factors that may increase individual susceptibility, as well as the more frequent contact with infective sources. In Italy, the major risk of infection appears connected with water plumbing systems of hotels, residential houses and hospitals, where oxygen bubble-humidifiers have been found to represent an important source of infection. On the contrary, the association of human infection with air conditioning systems has not been evidenced up-to-now.

The authors report five Danish patients affected by Legionnaire's disease observed during the 1987 spring. They focus on the epidemiological, clinical, and therapeutic aspect of the outbreak.

175 sera from children and 101 sera from adults both with respiratory illness of unknown origin were collected between September 1980 and February 1983 and studied by using the indirect immunofluorescence test for Legionnaires' disease. By using the criteria of the Center for Disease Control for a positive (fourfold increase in titer over 128 during convalescence) or presumptive (single titer greater than or equal to 256) serological test, 8 samples from adults (7.92%) and 11 samples from children (6.27%) gave a positive result. These results suggest that the frequency of Legionnaires' disease is similar in both adults and children.

A mini-epidemic consisting of 5 cases of Legionnaire's disease treated during september 1983 is reported. These patients shared many of the symptoms distinguishing the most common form of this disease in its severe or very severe form and some characteristic features of this case series are emphasised. It was impossible to trace the source of the outbreak, in spite of the fact that the mini-epidemic took place in an open situation. It is underlined that diagnosis is mainly clinical. The Legionella pneumophila bacteria should always be considered as one of the causal agents of bronchopneumonia, particularly when the following conditions are fulfilled: a) the disease takes the form of a confined, out-of-season, mini-epidemic; b) it is accompanied by multisystemic symptomatology and/or much greater involvement of general conditions that is usually to be expected in normal cases of bronchopneumonia. Since the disease is often fatal, erythromycin or rifampicin treatment should be started upon the slightest suspicion of contagion.

Legionella pneumophila was firstly recognized as the causative agent of a serious pneumonia about a decade ago. Since then a number of studies was carried out in order to define the epidemiological and clinical features of the microorganism. So far a high variability of the geographic distribution of the infection has been reported, with prevalences up to 50% of healthy populations. Therefore, a seroepidemiological survey was carried out on prevalence of Legionella pneumophila infections among healthy people in Naples. 562 serum specimens were randomly collected and examined by the indirect fluorescent antibody technique for antibodies against serogroups 1 to 6 of Legionella pneumophila, using 1:256 as the cut off titer. An overall prevalence of 23% was observed among the 562 persons tested. 24.5% among males and 21.9% among females had antibodies against Legionella pneumophila. There were no significant differences associated with sex and age, even though an apparent increase with age was observed. The highest prevalence was found for antibodies against serogroup 3 (9.4%). This finding was confirmed in all the age-sex groups, but among males aging between 21 and 40 years and among elderly people, 12.1% of persons tested had antibodies against only one serogroup of Legionella pneumophila, whilst 5.3%, 3.4% and 2.1% of subjects had antibodies against 2, 3 and 4 serogroups respectively. No serologic cross reactivity of Legionella pneumophila groups was found among seropositivities to different serogroups.