2012/2/9 Legionnaire’s Disease: History, Epidemiology; Assessment and Control of Environmental Outline of Presentation Factors leading to Outbreak Conditions Legionaries’ Disease History Occurrence Nature of Disease Route of Infection Presented at the Pathogenesis HKIOEH Professional Development Seminar Diagnosis and treatment Prevention of infection Understanding the ecology of Legionella February 8, 2012 Control Measures Risk assessment / management Joseph K. Kwan An Outbreak investigation The First Legionnaire’s Disease outbreak It occurred during The 1976 American Legionnaires’ annual meeting at a hotel in Philadelphia, Pennsylvania Upon returning home, 221 got sick, 34 died Investigation revealed a responsible bacteria This Bacterium was named (Legionella pneumophila) Records reveal similar outbreaks 1947 & 1967 It all started here in June 1976 Bellevue-Stratford Hotel in Philadelphia, Pennsylvania, USA Since 1976 Outbreaks continue to Legionella Problem in the USA take place all over the world Between 8000 to 18,000 cases reported each year World-wide Occurrence: 10 to 20 % fatality Range of 1 – 21 cases / million ~ 23% are hospital acquired Europe ~ 4.3 cases / million 30- 40% mortality rate HK ~3 cases / million Accuracy depends on efficiency of recognition and reporting!! ~30,000 patients have died from hospital acquired Legionnaires’ disease in the past 25 years No evidence of transmission from person to person All sources are environment related 1 2012/2/9 The situation in HK Legionella Outbreaks Continue – cases which raised public awareness: Some result in Court Cases http://www.youtube.com/user/isdgovhk#p/a/u/2/wq2p0Gcns9w http://www.youtube.com/user/isdgovhk#p/a/u/0/c00s-lDH-zQ The France Case The UK Case http://the-sun.on.cc/channels/news/20070224/20070224020822_0000.html http://www.thisisthelakedistrict.co.uk/farm/farming/display.var.458625.0.0.php http://www.guardian.co.uk/france/story/0,11882,1118151,00.html http://orientaldaily.on.cc/cnt/news/20111222/00176_025.html Legionnaires’ Disease is a reportable disease in HK http://www.chp.gov.hk/en/data/1/10/26/43/455.html Legionella Outbreaks Continue… Legionella Outbreaks Continue… Legionnaire’s disease victims support group Summary of Recent Cases http://www.hcinfo.com/outbreaks-news.htm http://www.q-net.net.au/~legion/legionnaires_disease_support_group.htm Characteristics of Legionella Bacteria Outbreak Occurrences Majority found in association with Gram negative rods Cooling towers Ubiquitous in natural water bodies Evaporative Condensers rivers, lakes and streams soil (moist) Hot and Cold Water Systems artificial water sources cooling towers, evaporative coolers, hot and cold water systems, shower facilities Spa Pools 2 2012/2/9 Outbreak Occurrences Mist From Cooling Tower Also found in Cutting Oil of Machine tools Clinical humidifiers for respiratory therapy Humidifiers in food display Decorative fountains Potting compost There are 2 forms of Legionaries’ Disease Pneumonia Pontiac Fever Legionnaire’s Disease (I) – Pneumonia Legionnaire’s Disease (I) – Pneumonia Rarely found in people <20 years old, most patients are Fulminating pneumonia 40-70 years old Low attack rate (< 5%) Severity of symptoms is proportional to age Relatively high fatality rate (up to 40%) Incubation period 2–10 days Male to Female affected – 3:1 Symptoms include general malaise, muscle pain, cough, Increased chance of developing serious illness in difficulty in breathing, headache, fever, gastrointestinal smokers, and in patients with chronic illnesses, renal pain, diarrhea, & respiratory failure diseases Higher mortality rate among immuno-compromised 3 2012/2/9 Route of Infection Legionnaire’s Disease (II) – Pontiac Fever Respiratory exposure to aerosols (2-5µm) Pontiac Fever: containing the Legionella bacteria Mild infection An airborne concentration of 0.02 cfu/l has been High attack rate ~80% found to be infectious Incubation Period: 24-48 hours Bacteria gain entry into alveoli Major symptoms is fever Self limiting in 2-5 days without antibiotics First discovered in Pontiac, Michigan Pathogenesis of Legionella Pathogenesis of Legionella Inhalation of aerosol containing Legionella Legionella releases various toxins and enzymes to Damages occur in alveoli invade tissue Legionella releases toxin & enzymes to invade tissues Hemolysin Cytotoxin Influence operation of WBC Endotoxin Suppress biochemical function of neutrophiles Lipase Stop fusion of lysosome and phagosome in Protease macrophages Phosphatase DNase Chymotrypsin Lung Tissue Slides Gram stain from lung Same lung tissue: deiterle silver showing no bacteria stain showing short rod-shaped (they stain poorly) Legionella bacteria 4 2012/2/9 Age distribution of cases showing a disease of the elderly Treatment of Legionnaire’s Disease Penicillin, Cephalosposin, Aminoglycosides) are ineffective Erythromycin – most effective Rifampin, Erythromycin can be used together Note that 'nosocomial' means acquired in hospitals as opposed to in the community. Ecology of Legionella Bacteria Growth rate of bacteria in water: primarily in hot water system Enhanced growth: 20o-45oC (70o-110oF) water temperature Will not grow < 20oC water temperature Will not survive > 60oC water temperature Residues, sludge, calcification layer & other organic materials in water can serve as nutrient for bacteria 20oC 35oC 46oC 50oC Ecology of Legionella Bacteria What is Biofilm? A polysaccharide matrix containing a mixing of Often found growing in components of water supply system microorganisms (bacteria, fungi, protozoa, algae) which live together as a community Other water borne organisms (algae, ameba, other bacteria) can serve as nutrient source Slimy to the touch Affinity for living in biofilm – symbiosis(?) Can stick to many surfaces (rubber, glass, polyurethane, copper, PVC, etc.) Microbes in biofilm require higher concentration of biocide and longer time to disinfect 1 ppm chlorine takes 60 – 200 time longer contact time to kill bacteria hidden inside amoeba than free living ones 50 ppm chlorine for 1 – 4 hours is required to disinfect water systems with biofilm 5 2012/2/9 Legionella bacteria Occurrence of Legionella in live inside protozoans Water Systems Concentration of Legionella A UK study indicates presence of Legionella in bacteria can vary significantly 55 % of hot water systems between water samples collected at different times!! 13 % of cold water systems 45 % of cooling towers A 2012 screening study in HK after case in Government building in Dec 2011 indicates Occurrence of 13% in domestic cold water systems There are at least 50 species of Legionella Bacteria 18 species have been associated with respiratory illness The Vast Majority of illnesses are caused by L. pneumonphila Legionella species and serogroups - Legionella adelaidensis Legionella longbeachae Legionella anisa Legionlla micdadei Legionella beliardensis Legionella monrovica Legionella birminghamensis Legionella moravica Legionella bozemanii Legionella nautarum Legionella brunensis Legionella oakridgensis Legionella busanensis Legionella parisiensis Legionella cherrii •At least 50 species have been confirmed, 70 serogroups Legionella cincinnatiensis Legionella pneumophila Legionella quateirensis Legionella dumoffii Legionella quinlivanii Legionella donaldsonii •L. pneumophila - species most often associated with disease Legionella rowbothamii Legionella drancourtii Legionella rubrilucens Legionella drozanskii Legionella sainthelensi Legionella erythra Legionella santicrucis Legionella fairfieldensis Legionella shakespearei Legionella fallonii •L. pneumophila - includes 16 serogroups Legionella spiritensis Legionella feeleii Legionella steigerwaltii Legionella geestiana Legionella taurinensis Legionella gratiana Legionella tucsonensis Legionella gresilensis Legionella wadsworthii Legionella hackeliae •L. pneumophila - Serogroup 1 most often associated with disease Legionella waltersii Legionella israelensis Legionella worsleiensis Legionella jamestowniensis Legionella londiniensis Legionella jordanis Legionella longbeachae Legionella lansingensis Legionella lytica Legionella pneumophila has 16 serogroups Culturing Legionella Bacteria Serogroup 1 accounts for 70 – 90 % of all cases of Legionnaires’ Diseases Requires L-cysteine as added nutrient Serogroup 1 has many subtypes: Grows best in High humidity plus 2 to 5% CO2 Examples: - Pontiac Buffered Charcoal Yeast Extract (BCYE) culture media is readily - Bellingham available in the market - Albuquerque - Knoxville - Johannesburg - Pittsburgh - Longbeach 6 2012/2/9 Culturing of Legionella Bacteria from Water Samples Identification of Legionella Bacteria Many microbes in water samples At least 50 species, 70 serogroups Eliminate other microbes in water sample by acid treatment (pH 2.2 for 5 mins) 0 heat treatment (50 C for 30 mins) Biochemical methods Use selective media to culture for Legionella Must add an essential amino acid nutrient- cysteine Culturing condition: 35oC 5%CO 80%RH 2 Takes 3 to 10 days to grow. Serotyping with monoclonal antibody Appearance of colony 1 to 2mm diameter White shinny surface Direct fluorescent antibody test Round, smooth, raised & smooth edge Gram negative rod shape 0.5µm x 1-3µm Polymerase Chain Reaction (PCR) Limitations of Various Detection Methods Risk Assessment for an Outbreak Direct immunofluorescence microscopy Is the water system