1. Legionella Dr. Harriet Whiley Most undervalued profession
It is responsible for almost everything you take for granted living in a developed country.

2. Legionellosis Legionnaires disease Pontiac Fever
A sever atypical pneumonia like infection
Infection
Pontiac Fever
A mild flu like illness
Allergic reaction to live/dead Legionella + endotoxins from non Legionella bacteria?
Asymptomatic Legionella
Increased Legionella antibodies with no symptoms

3. Incidence of Legionellosis
Across Europe (2011) = 4897 Legionellosis cases incidence rate of 0.97 cases per 100,000 (European Centre for Disease Prevention and Control, 2013)
Untied Stated (2011) = 4,202 Legionellosis cases incidence rate of 1.36 cases per 100,000 (Centers for Disease Control and Prevention 2013)
Australia (2014) = 427 Legionellosis cases (40 from SA) incidence rate of 1.8 per 100,000 (0.4 per 100,000 for SA)
149 Meningococcal cases
1840 dengue fever cases
12785 salmonellosis cases
82625 Chlamydia infection cases (Department of Health, National Notifiable Disease Surveillance System 2015).

4. True incidence of Legionellosis could be 20 times greater than the currently reported incidence.
In the US Legionella is the leading cause of all drinking water outbreaks (Centers for Disease Control and Prevention 2013).
The annual cost of hospitalisations due to Legionellosis in the United States is estimated to exceed US$716 million (Giambrone 2013)
Melbourne aquarium outbreak (2000)
125 cases, 95 hospitalisations, 4 deaths
loss of business/tourism etc.
$35 million legal claims

5. Electron microscope image of L. pneumophila
Legionellosis
19 species of Legionella cause human infection
L. pneumophila (aquatic) 80% of Legionella cases worldwide
L. longbeachae (potting mix) more common in Australia, New Zealand and China
Electron microscope image of L. pneumophila

6. Sources of L. pneumophila
Humidifiers
Cooling towers
Hydrotherapy pools
Birthing pool
Fountains
Respirator
Ice machines
Present in potable water – main reason its able to survive within these environments is its association with biofilms
showers
Dental units
Feeding tubes
Spas

7. For an aerosol ‘size is important!’
>10 µm nose and throat
5-10 µm upper and lower respiratory tract
2-5 µm lungs and conducting airways
>10 µm
>5-10 µm
2-5 µm
Eg. 90% shower aerosols 1-5 µm

8. L. pneumophila survival: Biofilm
Biofilm growth on hot water pipe
Biofilm growth on cooling tower pipe
Biofilm growth on plastic tubing

9. L. pneumophila survival - Amoeba
Electron micrographs of U937 macrophages (human white blood cell) (A) and Acanthamoeba polyphaga (B) infected by L. pneumophila (strain AA100) at 24 h. The infection is very similar in both host cells (Molmeret, et al. 2005).

10. L. pneumophila on BYCE GVPC agar
Legionella detection methods
Culture – the ‘gold standard’
PCR / qPCR
Fluorescent in situ hybridization (FISH)
solid phase cytometry
optical wavelight spectroscopy
Enzyme-Amplified Electrochemical Detection with DNA probe
Surface plasmon resonance immunosensor
Detection methods
L. pneumophila on BYCE GVPC agar

11. L. pneumophila on BYCE GVPC agar
Legionella detection methods
Culture – the ‘gold standard’
Limit of detection
Viable but non culturable
(VBNC)
Presence of disinfectants
High temperature
Low nutrients
If the legionella is at the flagellated stage of the life cycle
Present within a protozoa
FASLE NEGATIVES!!!!
Detection methods
L. pneumophila on BYCE GVPC agar

12. Cooling tower mandatory reporting to Department of Health
NSW / QLD / WA – No mandatory reporting
VIC – 3 consecutive >10 Legionella CFU/mL
ACT / SA / TAS - >1000 Legionella CFU/mL

13. Legionella targets for potable water pipelines using culture (gold standard) detection
Country
CFU/mL
Comments
France
<1000
<100
<50
Target for general public facilities
Target for prevention of nosocomial Infections
Target where at‑risk patients are
hospitalized
Germany
The Netherlands
Guideline target
United Kingdom

14. Investigation into South Australian potable water
Maximum concentrations
105 copies/mL Legionella spp,
103 copies/mL L. pneumophila
qPCR
Doesn’t differentiate between live and dead
Significant increases in concentration occurred during summer, low disinfection residual and dead end.
(Whiley et al. 2014)

15. Take home message Assume its always there!!! Prevent/remove biofilm
Maintain disinfection residual
For hot water systems make sure the temperature are being reached – don’t ever have warm water sitting in the pipes
Protect the high risk groups

16. Questions? 

17. References
Centers for Disease Control and Prevention (CDC). (2013). Surveillance for waterborne disease outbreaks associated with drinking water and other nonrecreational water-United States,  MMWR. Morbidity and mortality weekly report, 62(35), 714.
European Centre for Disease Prevention and Control. (2014) Legionnaires’ disease in Europe, Stockholm: ECDC.
Department of Health. (2015). National Notifiable Disease Surveillance System, Australian Government
Giambrone, G. P. (2013). National Cost of Hospitalization for Legionnaires' Disease, CSTE Annual Conference, Cste.
Molmeret, M., M. Horn, M. Wagner, M. Santic, and Y. Abu Kwaik. (2005). Amoebae as training grounds for intracellular bacterial pathogens. Appl Environ Microbiol 71:20–8
Whiley, H., Keegan, A., Fallowfield, H., & Bentham, R. (2014). Detection of Legionella, L. pneumophila and Mycobacterium avium complex (MAC) along potable water distribution pipelines. International journal of environmental research and public health, 11(7),