Prevalence of anti-legionella antibodies among Italian hospital workers.

This study evaluated the prevalence of anti-legionella antibodies in workers at hospitals with a long-term history of legionella contamination. The hospitals are located in Milan and Turin, northern Italy, and in Naples and Bari, southern Italy. Antibody prevalence and titres of healthcare workers, medical and dental students and blood donors were assessed. In total 28.5% of subjects were antibody positive, most frequently to L. pneumophila serogroups 7-14. Major differences were observed in seroprevalence and type of legionella antibody in persons from different geographic areas. Healthcare workers had a significantly higher frequency of antibodies compared with blood donors in Milan (35.4 vs 15.9%, P<0.001), whereas in Naples both groups exhibited high antibody frequency (48.8 vs 44.0%) and had a higher proportion of antibodies to legionella serogroups 1-6. Dental workers had a higher seroprevalence than office staff in Bari, but not in Turin, where daily disinfecting procedures had been adopted to avoid contamination of dental unit water. No association was found between the presence of antibodies and the presence of risk factors for legionellosis, nor with the occurrence of pneumonia and/or flu-like symptoms. In conclusion, the presence of legionella antibodies may be associated with occupational exposure in the hospital environment, but there was no evidence of any association with disease.

Risk factors for particulate and microbial contamination of air in operating theatres.

This study was designed to standardize dust collection in recently built operating theatres equipped with a continuous monitoring system. The objectives were to establish the relationship between microbiological and dust contamination, and then to compare those parameters with the main indicators of surgical activity in order to better define risk factors affecting air quality. The air quality during 23 surgical operations was studied in three conventionally ventilated operating theatres. Microbiological air counts were taken using both passive and active sampling methods. Air dust particles, > or =0.5 and > or =5 microm in size, were measured using a light-scattering particle analyser. The overall dust load was mainly (98%) composed of fine particulate matter, most probably due to its longer suspension time before settlement. These particles positively correlated with operation length, but not with surgical technique, suggesting that fine particles may be a good tracer of operation complexity. In contrast, the surgical technique was the main predictor for the concentration of particles > or =5 microm, with a higher risk from general conventional surgery compared with scope surgery. The frequency of door-opening, taken as an index of staff and visitor movement, was the main negative predictor of over-threshold values of both fine and larger dust particles but, conversely, was a positive predictor of raised bacterial counts.

[Environmental diffusion of Legionella spp and legionellosis frequency among patients with pneumonia: preliminary results of a multicentric Italian survey]. / Diffusione ambientale di Legionella spp e frequenza di legionellosi in pazienti affetti da polmonite: primi risultatidi uno studio multicentrico italiano.

A multicentric Italian investigation on legionnaires' disease is in course to clarify host factors as well as pathogen associated characteristics involved in the infection/disease. The main goal of the research plan is to account for some critical aspects concerning identification and prevention of legionellosis. To improve knowledge on factors associated with Legionella spp colonisation in hot waters, to detect cases and to characterize risk factors in subjects which develop pneumonia are specific objectives of the research programme. Preliminary results show that hot waters of houses and hotels are frequently contaminated (22.6% and 54.6%, respectively), mainly by L. pneumophila. Microbial concentrations were low in domestic waters (<1.000 ufc/l), but higher in samples from the hotels (geom. mean 1.85 x 10(3) ufc/l). Warming system, age of the plant, type of building were risk factors significantly associated with Legionella spp positivity. The active surveillance on patients affected by pneumonia with search for Legionella urinary antigen allowed the identification of 34 cases, 3 of which of nosocomial origin, corresponding to 4.2% of the screened pneumonia. After informed consent, 26 subjects were recruited for a case-control-study to clarify risk factors for the disease.