A preliminary assessment of the occupational risk of acquiring Legionnaires' disease for people working in telephone manholes, a new workplace environment for Legionella growth

• Published in: American journal of infection control 2010-09, Vol.38 (7), p.540-545
• Main Authors: Ricci, Maria Luisa, Fontana, Stefano, Bella, Antonino, Gaggioli, A, Cascella, R, Cassone, Antonio, Scaturro, Maria
• Format: Article
• Language: English
• Subjects: Adult; antibody titer; Bacterial diseases; Bacterial diseases of the respiratory system; Biological and medical sciences; Colony Count, Microbial; Environmental Microbiology; Epidemiology. Vaccinations; Female; General aspects; Gram-negative bacteria; Human bacterial diseases; Humans; Infection Control; Infectious Disease; Infectious diseases; Italy; Legionella; Legionella pneumophila - isolation & purification; Legionnaires' Disease - epidemiology; Legionnaires' Disease - prevention & control; Male; manhole; Medical sciences; Middle Aged; Occupational Diseases - epidemiology; Occupational Diseases - prevention & control; Occupational Exposure - statistics & numerical data; Occupational health; occupational risk; Pneumology; Regression analysis; Respiratory system : syndromes and miscellaneous diseases; Risk Assessment; Risk factors; Telephone; Workers
• ISSN: 0196-6553; 1527-3296
• DOI: 10.1016/j.ajic.2010.04.194

Background Telephone manholes (TMs) are underground wells, used in Italy by the telecommunication companies to locate telephone networks. Following a fatal case of Legionnaires' disease (LD), acquired during working activity in a TM, we investigated whether Legionella was present in TMs and could be a risk for manhole workers (MWs). Methods Three hundred fifty-three environmental samples were collected from 100 TMs, and serum antibody titer against Legionella pneumophila and Legionella species non- pneumophila was determined from both MWs and control non-manhole workers. Results L pneumophila and Legionella species non -pneumophila were detected in 28% of water samples, in 8% of the biofilm, and in 6% of sediment matrices taken in TMs, in a concentration range of 102 to 104 colony-forming units/L. No Legionella was found in TM air samples. Although there was a statistically significant difference ( P = .027) in antibody titer to L pneumophila serogroup 1 (Lp1) between MWs and non-manhole workers, a multivariate logistic regression analysis showed a significant association between antibody against Lp1 and both age group and the practice of aquatic sports. Conclusion Although further investigations will be performed to quantify the risk of acquiring legionellosis, this preliminary study demonstrates for the first time the presence of Legionella , including human pathogenic species, in a working environment such as TM.