Preventing Legionellosis Outbreaks

Alaska Infection Control ConferenceAnchorage, AK

October 8, 2019Larry Lee, CIH, Pacific Industrial Hygiene LLC

Rob Hinton, University of Washington Medical Center

PreventionA lot can be learned about prevention

by going through an outbreak

Prevention

• Prevention = Risk minimization

• All the measures we will discuss will minimize risk and the chance that an outbreak can occur

• But they cannot guarantee that it will never happen

• “Life, uh, finds a way” –Jurassic Park

Legionella bacteria• Legionellosis – typically a

respiratory infection caused by Legionella bacteria

• ~50 Legionella species• 19 human pathogenic species

• Legionella pneumophila• Gram negative, flagellated rod,

0.3 – 0.9 x 2 microns• ~90% of infections• Serotypes 1, 4 & 6 cause most

infections• 16 serotypes – surface antigens

Ecology Legionella bacteria?

• Fresh water & soil, dependent on biofilm• Legionella Life Cycle

• Eaten by ameoba• Ameoba eaten by paramecium• Paramecium dies & releases Legionella

• Survive temperatures 41 to 145˚F• Thrive between 77 to 115˚F• Biofilm and bacteria can colonize building water systems

• Piping, cooling towers, faucets, ice machines, fountains, etc.

Building ecology

• Hospital sources• Potable water systems, sinks, shower heads, spas and jet tubs, ice machines,

humidifiers, dialysis water, water features, cooling towers, emergency showers & water cooled-equipment

• Community sources• Domestic water systems, spas & whirlpools, sprinklers & water features

(hotels, flower shows, restaurants & cruise ships), vegetable misters, humidifiers, cooling towers & water cooled-equipment

Building ecology• Conditions that promote Legionella & biofilm growth in plumbing

• Low chlorine/oxidant concentrations• Low flowing or stagnant water – chlorine/oxidant becomes

“consumed”• High sediment levels & scale

• Consumes chlorine/oxidant• Interferes with chlorine/oxidant efficacy

• Preferred temperature – 77⁰ F to 115⁰ F• High pH – chlorine less effective• Dead-legs

• Sections of the plumbing systems in which there is low flowing or stagnant water

• Physical dead-legs: capped off lengths of piping• Operational dead-legs: rooms, fixtures and equipment that is

seldom used

Building ecologyOperational dead legs

Patients most at risk

• Advanced age• Male• Smoking history• Alcohol abuse• Chronic pulmonary disease• Immune suppression

• Transplant• AIDS• Underlying pulmonary disorder

(children)

Legionellosis• Onset

• 2 to 10 days from exposure• Pontiac fever

• Self-limiting (24 – 48 hours) flu-like illness without pneumonia• Legionellosis

• Cough & low grade fever progresses to:• Pneumonia • Stupor• Organ failure• Fever exceeds 40 C/104 F• Headache• Confusion• Pleuritic chest pain• GI symptoms

• < 10% mortality with quinolone therapy

Actions

• Water Management Plan• Ownership & accountability

Actions

• Know your water• Who provides your water• Where your water comes from and how it

is delivered• Straight to pipe or via reservoirs, etc.

• Characterize your water: Chlorine/oxidant, pH, temperature, sediment

ActionsBe informed about delivery system

changes & work

Actions

• Characterize your water at the entry point: Chlorine oxidant, pH, temperature, sediment, water pressure

• Determine how water moves through your building(s)

• Characterize your water at the distal outlets

Actions

• Search for, and remove dead-legs

• Identify operational dead-legs• Flushing plan

• Identify construction dead-legs• Flushing plan

Actions

• Identify likely at-risk patients & locations• Transplant• Oncology• Respiratory therapy• Geriatrics• CCU/ICU• Birthing Center• Pediatrics – Neonatal ICU• Burns

Actions

• Inventory your distal outlets & equipment• Prioritize primary water contacts for at-risk

patients• Sinks, showers & toilets• Ice machines• Hydrotherapy & birthing tubs• Scrub sinks• Bottle fillers• CPAP machines• Nebulizers• Cooling towers

Actions• Inventory & assess performance of critical

plumbing equipment & systems• Hot water tanks

• Validate cleaning & maintenance• Temperature setting & actual

temperatures• Interties• Cross connections• Backflow

Actions

• Cooling towers• Validate cleaning &

treatment• Validate maintenance

schedule

Actions

• Remove/replace carbon filters• Removes chlorine from water

Actions

• Conduct risk assessment• Water status• At-risk patients• Primary water contacts

• Prioritize risk of contamination

• High-risk for colonization outlets & equipment

• High exposure (consumption & aerosolization) scenarios & equipment

Actions

• Legionella sampling

• Ultimate validation tool & commitment

Actions

• Prepare for an outbreak• Water restrictions

• Bottled water, ice & vendor/supplies• Bathing & showering• Handwashing?

• Intervention• Hyperchlorination/oxidant, CuAg & filtration

• Pre-qualify vendor & contract documents• Heat treatment

• System capacity & system capability• POU filters

• Hardware requirements & availability• Communications

• Transparency• Sampling

• Pre-qualify lab & lab sampling support

Actions

• Put your eyes on all that you are doing to validate your process and actions

Conclusion

• To be in the best position you can

• Develop a great plan• Own the plan• Carry out the plan• Validate the plan