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Community-acquired versus nosocomial Legionella pneumonia: Lessons learned from an epidemiologic investigation
Community-acquired versus nosocomial Legionella pneumonia: Lessons learned from an epidemiologic investigation Epidemiologically, the peak incidence of legionella community-acquired pneumonia (CAP) is in the summer/fall, but cases may occur anytime during the year. The peak age incidence of Legionnaire’s disease is in the elderly population, but Legionella CAP occurs in all age groups. The incubation period for Legionnaire’s disease is 2 to 10 days. Typically, legionella CAP occurs sporadically.1-4 Clinical presentation of Legionnaire’s disease is independent of legionella species and Legionella nosocomial pneumonia (NP) is indistinguishable clinically from legionella CAP.1-4 In contrast to sporadic legionella CAP, legionella NP occurs in clusters/outbreaks.5-7 The natural habitat of legionella species are in the water/soil, and legionella thrive in warm/stagnant water. However, high numbers of legionella species in water supplies increase the potential for clinical cases of Legionnaire’s disease, but low numbers of legionella may be present in water supplies without clinical cases of Legionnaire’s disease.8,9 Outbreaks of Legionnaire’s disease have been reported from chronic care facilities and hospitals as well as from a variety of nonmedical facilities, eg, hotels.10 Small outbreaks of nosocomial/ facility-related Legionnaire’s disease that occur over a short period of time point to a legionella contaminated potable water exposure. Such small outbreaks often occur as a result of stagnant legionella contaminated water in pipes or are related to water pipes in/ near the facility.11,12 In contrast, sudden appearance of large numbers of Legionnaire’s pneumonias occurring over short period of time suggest airborne spread, eg, from legionella contaminated water towers.13-15 Obviously, the hospital/facility-related outbreaks do not have a seasonal distribution as with communityacquired Legionnaire’s disease.5 Over the past 3 decades at our hospital, we have had an ongoing extensive experience with legionella CAP. We have seen legionella CAP in a wide variety of hosts in all age groups and caused by a variety of legionella species. We are very familiar with the clinical manifestations 0196-6553/$36.00 Copyright ª 2011 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
of Legionnaire’s disease as our experience has continued over the years.2,4 Ever vigilant for Legionnaire’s disease at our hospital, we have not had a problem in suspecting/diagnosing legionella pneumonias. Last fall, a case of Legionnaire’s disease occurred in our hospital. The patient was a 52-year-old male who worked in construction/excavation. He was admitted to the hospital following a fall while repairing a house roof. On hospital day 3, he developed pneumonia with the clinical features of Legionnaire’s disease. He was subsequently diagnosed as Legionnaire’s disease by legionella urinary antigen, eg, L pneumophila (serogroups 1-6).4 Because his occupation exposed him to legionella via water/soil contact and because his legionella CAP occurred so early in his hospitalization admission, ie, day 3, we thought this was a case of communityacquired and not hospital-acquired Legionnaire’s disease. The Department of Health thought this case might be a potential case of nosocomial Legionnaire’s disease. We contended that, because this case was a single sporadic occurrence, and not part of a cluster/ outbreak, that legionella CAP was most likely. We also stated that we had never had a cluster/outbreak of legionella NP at our hospital, a 600-bed, universityaffiliated tertiary care teaching hospital. Although the hospital water supply was never tested for legionella per se, years ago, we implemented preemptive changes in the hospital’s water system to prevent legionella from establishing itself, ie, elimination of stagnant water loops/dead end pipes. However, Department of Health requested testing of all patients in the hospital at the time of the Legionnaire’s disease case with sputum culture for legionella species and legionella urinary antigen testing. We were also requested to test the hospital’s water supply for legionella species including water sources in the patient’s room and ward. In addition, we were requested to prospectively test all patients with presumed/definite NP for a 3-month period following the case to have their respiratory secretions cultured for legionella species and urinary antigen testing performed. Our epidemiologic investigation indicated that none of the patients hospitalized at the time of the legionella case were either sputum culture positive or urinary antigen positive for legionella. Extensive culturing of the hospital’s water supply for legionella, including the room and ward water where the patient was hospitalized, was done. Some water samples were positive for legionella in very low concentrations, which were well below the accepted limits for legionella. In addition, prospective testing of hospitalized patients with NP was conducted over a 3-month period, and none of these patients had either positive respiratory secretion cultures for legionella or positive legionella urinary antigen tests. Since no cluster/outbreak occurred before, during, or after the case, we 901
902
American Journal of Infection Control December 2011
Letter to the Editor
believe that our initial epidemiologic assessment was correct and that the case of Legionnaire’s disease was, in fact, a sporadic case of legionella CAP. There are lessons to be learned from our investigation of a possible nosocomial Legionnaire’s disease. In the hospital setting, Infectious Disease and Infection Control are in the best position to recognize a cluster/ outbreak of legionella NP. With legionella NP, the main difficulty is not in recognizing Legionnaire’s disease or being alert to the cluster/outbreak of legionella NP cases; rather, it is in determining the source/extent of the contaminated water supply containing high numbers of legionella species.6-8,12 Because of the complexity and redundancy of hospital water systems, an experienced evaluation/testing consultant and reference laboratory with expertise in legionella testing of water systems of facilities/hospitals is essential. We were fortunate to have the benefit of an expert consultant, Mr. Tim Keane of Legionella Risk Management from Chalfont, Pennsylvania, who was key in making the proactive recommendations for changes in our water supply system years ago. His assistance was invaluable on assessing/testing our water system during the current epidemiologic investigation. Two approaches have been used to prevent legionella NP. One approach is to proactively evaluate the hospital’s water system to eliminate stagnant water to prevent legionella growth in low-flow loops/dead end pipes.16,17 This was done years ago at our hospital under Mr. Keane’s direction. Another approach involves surveillance cultures of the hospital water supply for legionella.18 We have not engaged in surveillance culturing of the hospital’s water system for legionella species. In hospitals with a previous cluster/outbreak of legionella NP, hospital water surveillance for legionella species is recommended. Even if legionella organisms are cultured from a hospital’s water supply, a causal relationship is proven only if the numbers of legionella are high and the legionella species in the water supply is the same as the species causing legionella NP. In hospitals without previous legionella NP such as ours, we believe that cluster/outbreak of legionella NP, not single cases, should be the trigger for an epidemiologic investigation to determine the source/extent of legionella in the hospital’s water supply.1,4,5 We believe that, without an antecedent cluster/outbreak of legionella, a full investigation is not warranted for a single/sporadic case; particularly, when epidemiologically, legionella CAP was much more likely. Our view is that a cluster/outbreak of 2 or 3 cases of legionella pneumonia rather than a single case should be the threshold to initiate an extensive/expensive epidemiologic investigation for potential legionella NP. Conflicts of interest: None to report.
Burke A. Cunha, MD Infectious Disease Division, Winthrop-University Hospital, Mineola, NY, and State University of New York School of Medicine, Stony Brook, NY Valsamma Thekkel, RN, MSN, CIC Infection Control Section, Winthrop-University Hospital, Mineola, NY Paul E. Schoch, PhD Microbiology Laboratory, Winthrop-University Hospital, Mineola, NY Address correspondence to Burke A. Cunha, MD, Hospital Epidemiologist Chief, Infectious Disease Division, Winthrop-University Hospital, Mineola, NY 11501.
References 1. Kirby BD, Harris AA. Nosocomial Legionnaire’s disease. Semin Respir Infect 1987;2:255-61. 2. Cunha BA, Strampfer MJ, Yannelli B. Nosocomial Legionnaire’s disease. Hosp Physician 1987;23:41-3. 3. Roig J, Sabria M, Pedro-Botet ML. Legionella spp.: community acquired and noocomial infections. Curr Opin Infect Dis 2003;16:145-51. 4. Cunha BA. Legionnaires’ disease: clinical differentiation from typical and other atypical pneumonias. Infect Dis Clin North Am 2010;24: 73-105. 5. Levy PY, Teysseire N, Etienne J, Raoult D. A nosocomial outbreak of Legionella pneumophila caused by contaminated transesophageal echocardiography probes. Infect Control Hosp Epidemiol 2003;24: 619-22. 6. Ozerol IH, Bayraktar M, Cizmeci Z, Durmaz R, Akbas E, Yildirim Z, et al. Legionnaire’s disease: a nosocomial outbreak in Turkey. J Hosp Infect 2006;62:50-7. 7. Palmore TN, Stock F, White M, Bordner M, Michelin A, Bennett JE, et al. A cluster of cases of nosocomial legionnaires disease linked to a contaminated hospital decorative water fountain. Infect Control Hosp Epidemiol 2009;30:764-8. 8. Sabria M, Modol JM, Garcia Nunez, Reynaga E, Pedro-Botet ML, Sopena N, et al. Environmental cultures and hospital-acquired Legionnaire’s disease: a 5 year prospective study in 20 hospitals in Catalonia, Spain. Infect Control Hosp Epidemiol 2004;25:1072-6. 9. Stout JE, Muder RR, Mietzner S, Wagener MM, Perri MB, DeRoos K, et al. Role of environmental surveillance in determining the risk of hospital-acquired legionellosis: a national surveillance study with clinical correlations. Infect Control Hosp Epidemiol 2007;28: 818-24. 10. Kool JL, Bergmire-Sweat D, Butler JC, Brown EW, Peabody DJ, Massi DS, et al. Hospital characteristics associated with colonization of water systems by Legionella and risk of nosocomial legionnaire’s disease: a cohort study of 15 hospital. Infect Control and Hosp Epidemiol 1999;20:798-805. 11. Joseph CA, Ricketts KD, Yadav R, Patel S. Travel-associated Legionnaire’s Disease in Europe in 2009. Euro Surveill 2010;15: 19683. 12. Chien ST, Hsueh JC, Lin HH, et al. Epidemiological investigation of a case of nosocomial Legionnaires’ disease in Taiwan: implications for routine environmental surveillance. Clin Microbiol Infect 2010;16: 761-3. 13. Keramarou M, Evans MR. A community outbreak of Legionnaire’s disease in South Wales, August-September 2010. Euro Surveill 2010;15: 19691. 14. Campese C, Bitar D, Jarraud S, Maine C, Forey F, Etienne J, et al. Progress in the surveillance and control of Legionella infection in France 1998-2008. Int J Infect Dis 2011;15:e30-7.
www.ajicjournal.org Vol. 39 No. 10 15. Mouchtouri VA, Goutziana G, Kermastinou J, Hadjichristodoulou C. Legionella species colonization in cooling towers: risk factors and assessment of control measures. Am J Infect Control 2010; 38:50-5. 16. Squier CL, Stout JE, Krystofiak S, McMahon J, Wagener MM, Dixon B, et al. A proactive approach to prevention of health care-acquired Legionnaire’s disease: the Allegheny County (Pittsburgh) experience. Am J Infect Control 2005;33:360-7.
Letter to the Editor
903
17. Sabria M, Yu VL. Hospital-acquired legionellosis: solutions for a preventable infection. Lancet Infect Dis 2002;2:368-73. 18. Boccia S, Laurenti P, Borella P, Moscato U, Capalbo G, Cambieri A, et al. Prospective 3-year surveillance for nosocomial and environmental Legionella pneumophila: implications for infection control. Infect Control Hosp Epidemiol 2006;27:459-65. doi:10.1016/j.ajic.2011.03.021
of Legionnaire’s disease as our experience has continued over the years.2,4 Ever vigilant for Legionnaire’s disease at our hospital, we have not had a problem in suspecting/diagnosing legionella pneumonias. Last fall, a case of Legionnaire’s disease occurred in our hospital. The patient was a 52-year-old male who worked in construction/excavation. He was admitted to the hospital following a fall while repairing a house roof. On hospital day 3, he developed pneumonia with the clinical features of Legionnaire’s disease. He was subsequently diagnosed as Legionnaire’s disease by legionella urinary antigen, eg, L pneumophila (serogroups 1-6).4 Because his occupation exposed him to legionella via water/soil contact and because his legionella CAP occurred so early in his hospitalization admission, ie, day 3, we thought this was a case of communityacquired and not hospital-acquired Legionnaire’s disease. The Department of Health thought this case might be a potential case of nosocomial Legionnaire’s disease. We contended that, because this case was a single sporadic occurrence, and not part of a cluster/ outbreak, that legionella CAP was most likely. We also stated that we had never had a cluster/outbreak of legionella NP at our hospital, a 600-bed, universityaffiliated tertiary care teaching hospital. Although the hospital water supply was never tested for legionella per se, years ago, we implemented preemptive changes in the hospital’s water system to prevent legionella from establishing itself, ie, elimination of stagnant water loops/dead end pipes. However, Department of Health requested testing of all patients in the hospital at the time of the Legionnaire’s disease case with sputum culture for legionella species and legionella urinary antigen testing. We were also requested to test the hospital’s water supply for legionella species including water sources in the patient’s room and ward. In addition, we were requested to prospectively test all patients with presumed/definite NP for a 3-month period following the case to have their respiratory secretions cultured for legionella species and urinary antigen testing performed. Our epidemiologic investigation indicated that none of the patients hospitalized at the time of the legionella case were either sputum culture positive or urinary antigen positive for legionella. Extensive culturing of the hospital’s water supply for legionella, including the room and ward water where the patient was hospitalized, was done. Some water samples were positive for legionella in very low concentrations, which were well below the accepted limits for legionella. In addition, prospective testing of hospitalized patients with NP was conducted over a 3-month period, and none of these patients had either positive respiratory secretion cultures for legionella or positive legionella urinary antigen tests. Since no cluster/outbreak occurred before, during, or after the case, we 901
902
American Journal of Infection Control December 2011
Letter to the Editor
believe that our initial epidemiologic assessment was correct and that the case of Legionnaire’s disease was, in fact, a sporadic case of legionella CAP. There are lessons to be learned from our investigation of a possible nosocomial Legionnaire’s disease. In the hospital setting, Infectious Disease and Infection Control are in the best position to recognize a cluster/ outbreak of legionella NP. With legionella NP, the main difficulty is not in recognizing Legionnaire’s disease or being alert to the cluster/outbreak of legionella NP cases; rather, it is in determining the source/extent of the contaminated water supply containing high numbers of legionella species.6-8,12 Because of the complexity and redundancy of hospital water systems, an experienced evaluation/testing consultant and reference laboratory with expertise in legionella testing of water systems of facilities/hospitals is essential. We were fortunate to have the benefit of an expert consultant, Mr. Tim Keane of Legionella Risk Management from Chalfont, Pennsylvania, who was key in making the proactive recommendations for changes in our water supply system years ago. His assistance was invaluable on assessing/testing our water system during the current epidemiologic investigation. Two approaches have been used to prevent legionella NP. One approach is to proactively evaluate the hospital’s water system to eliminate stagnant water to prevent legionella growth in low-flow loops/dead end pipes.16,17 This was done years ago at our hospital under Mr. Keane’s direction. Another approach involves surveillance cultures of the hospital water supply for legionella.18 We have not engaged in surveillance culturing of the hospital’s water system for legionella species. In hospitals with a previous cluster/outbreak of legionella NP, hospital water surveillance for legionella species is recommended. Even if legionella organisms are cultured from a hospital’s water supply, a causal relationship is proven only if the numbers of legionella are high and the legionella species in the water supply is the same as the species causing legionella NP. In hospitals without previous legionella NP such as ours, we believe that cluster/outbreak of legionella NP, not single cases, should be the trigger for an epidemiologic investigation to determine the source/extent of legionella in the hospital’s water supply.1,4,5 We believe that, without an antecedent cluster/outbreak of legionella, a full investigation is not warranted for a single/sporadic case; particularly, when epidemiologically, legionella CAP was much more likely. Our view is that a cluster/outbreak of 2 or 3 cases of legionella pneumonia rather than a single case should be the threshold to initiate an extensive/expensive epidemiologic investigation for potential legionella NP. Conflicts of interest: None to report.
Burke A. Cunha, MD Infectious Disease Division, Winthrop-University Hospital, Mineola, NY, and State University of New York School of Medicine, Stony Brook, NY Valsamma Thekkel, RN, MSN, CIC Infection Control Section, Winthrop-University Hospital, Mineola, NY Paul E. Schoch, PhD Microbiology Laboratory, Winthrop-University Hospital, Mineola, NY Address correspondence to Burke A. Cunha, MD, Hospital Epidemiologist Chief, Infectious Disease Division, Winthrop-University Hospital, Mineola, NY 11501.
References 1. Kirby BD, Harris AA. Nosocomial Legionnaire’s disease. Semin Respir Infect 1987;2:255-61. 2. Cunha BA, Strampfer MJ, Yannelli B. Nosocomial Legionnaire’s disease. Hosp Physician 1987;23:41-3. 3. Roig J, Sabria M, Pedro-Botet ML. Legionella spp.: community acquired and noocomial infections. Curr Opin Infect Dis 2003;16:145-51. 4. Cunha BA. Legionnaires’ disease: clinical differentiation from typical and other atypical pneumonias. Infect Dis Clin North Am 2010;24: 73-105. 5. Levy PY, Teysseire N, Etienne J, Raoult D. A nosocomial outbreak of Legionella pneumophila caused by contaminated transesophageal echocardiography probes. Infect Control Hosp Epidemiol 2003;24: 619-22. 6. Ozerol IH, Bayraktar M, Cizmeci Z, Durmaz R, Akbas E, Yildirim Z, et al. Legionnaire’s disease: a nosocomial outbreak in Turkey. J Hosp Infect 2006;62:50-7. 7. Palmore TN, Stock F, White M, Bordner M, Michelin A, Bennett JE, et al. A cluster of cases of nosocomial legionnaires disease linked to a contaminated hospital decorative water fountain. Infect Control Hosp Epidemiol 2009;30:764-8. 8. Sabria M, Modol JM, Garcia Nunez, Reynaga E, Pedro-Botet ML, Sopena N, et al. Environmental cultures and hospital-acquired Legionnaire’s disease: a 5 year prospective study in 20 hospitals in Catalonia, Spain. Infect Control Hosp Epidemiol 2004;25:1072-6. 9. Stout JE, Muder RR, Mietzner S, Wagener MM, Perri MB, DeRoos K, et al. Role of environmental surveillance in determining the risk of hospital-acquired legionellosis: a national surveillance study with clinical correlations. Infect Control Hosp Epidemiol 2007;28: 818-24. 10. Kool JL, Bergmire-Sweat D, Butler JC, Brown EW, Peabody DJ, Massi DS, et al. Hospital characteristics associated with colonization of water systems by Legionella and risk of nosocomial legionnaire’s disease: a cohort study of 15 hospital. Infect Control and Hosp Epidemiol 1999;20:798-805. 11. Joseph CA, Ricketts KD, Yadav R, Patel S. Travel-associated Legionnaire’s Disease in Europe in 2009. Euro Surveill 2010;15: 19683. 12. Chien ST, Hsueh JC, Lin HH, et al. Epidemiological investigation of a case of nosocomial Legionnaires’ disease in Taiwan: implications for routine environmental surveillance. Clin Microbiol Infect 2010;16: 761-3. 13. Keramarou M, Evans MR. A community outbreak of Legionnaire’s disease in South Wales, August-September 2010. Euro Surveill 2010;15: 19691. 14. Campese C, Bitar D, Jarraud S, Maine C, Forey F, Etienne J, et al. Progress in the surveillance and control of Legionella infection in France 1998-2008. Int J Infect Dis 2011;15:e30-7.
www.ajicjournal.org Vol. 39 No. 10 15. Mouchtouri VA, Goutziana G, Kermastinou J, Hadjichristodoulou C. Legionella species colonization in cooling towers: risk factors and assessment of control measures. Am J Infect Control 2010; 38:50-5. 16. Squier CL, Stout JE, Krystofiak S, McMahon J, Wagener MM, Dixon B, et al. A proactive approach to prevention of health care-acquired Legionnaire’s disease: the Allegheny County (Pittsburgh) experience. Am J Infect Control 2005;33:360-7.
Letter to the Editor
903
17. Sabria M, Yu VL. Hospital-acquired legionellosis: solutions for a preventable infection. Lancet Infect Dis 2002;2:368-73. 18. Boccia S, Laurenti P, Borella P, Moscato U, Capalbo G, Cambieri A, et al. Prospective 3-year surveillance for nosocomial and environmental Legionella pneumophila: implications for infection control. Infect Control Hosp Epidemiol 2006;27:459-65. doi:10.1016/j.ajic.2011.03.021