Warschau Nov. 2008 1

Dr. K. Luden

Legionella type bacteria

in

domestic distribution systems(house installations)

Dr. Katrin Luden

Legionella type bacteria

Dr. K. Luden

Legionella

are fresh water bacteria (~ 50 species, all of them potentially pathogenic to humans)

grow best in warm watere.g. in warm drinking water supply, pools (filter),air condition-systems or cooling towers

hardly grow <20°C and die at >60°C

infections are transmitted by inhalation of aerosols rarely by aspiration (90 % of infections caused by L. pneumophila)

cause Pontiac-fever and legionaires disease

Infections caused by Legionella

Dr. K. Luden

Pontiac-fever

acute self-limiting influenza-like infection without pneumonia

Incubation time: 2-3 daysCases ~800.000 – 1.5 billion / year (estimate of RKI)

Legionaires disease

Pneumonia (fever, chills, cough) sometimes fatalIncubation time: 2-10 daysCases: ~ 6.000 - 20.000 / year (estimate of RKI)Fatal cases: ~ 1.000 - 3.000 / year (estimate of RKI)

Drinking water directive 98/83/EC

Dr. K. Luden

Legionella not mentioned but

General obligations (Article 4):

Water shall be clean if it: is free from micro-organisms which in numbers or concentrations, constitute a potential danger to human health

Article 5 (3) Quality standards

“A Member State shall set values for additional parameters not included in Annex I where the protection of human health within its national territory or part of it so requires. The values set should, as a minimum, satisfy the requirements of Article 4(1)(a).”

German Drinking water directive (DWD)

Dr. K. Luden

§ 18 Monitoring by public health authorities

(1) Public health authorities supervise the water supply ... from domestic distribution systems from which water is made available for the public, in particular in schools, kindergartens, hospitals, restaurants and other communal facilities, regarding the compliance to the requirements of the regulation by appropriate examinations.

German Drinking water directive (DWD)

Dr. K. Luden

Legionella mentioned twice:

§20 order of the public health authorities

public health authorities can order analysis of additional parameters considering the circumstances of the individiual case ... e.g. Legionella ...

And

Audit monitoring (Annex)

Audit monitoring includes the investigation on Legionella in central drinking water warming systems as part of domestic distribution systems that supply water to the public.

Rationale

Dr. K. Luden

Due to the considerable potential danger to human health connected to Legionella in warm water domestic distribution systems water from those systems has to be monitored for Legionella in facilities supplying water to the public.

BUT

Questions

Dr. K. Luden

What is the aim of the monitoring?

Detection of systemic contamination oracute risk assessment?

What parametric values are to be used for assessment of results?

Sampling: where, how many samples, how, when?

Aim of monitoring

Dr. K. Luden

Recommendations by NLGA (2006) and FEA (2007):

detection of systemic contamination

The purpose in Lower Saxony is to gather information on systemic contamination with comparable results due to harmonized sampling techniques and sample identification using a coding system.

The laboratory method for detection of Legionella was covered as well because ISO 11731 was not translated into a DIN.

Technical Standards

Dr. K. Luden

DIN 1988 (1988): technical standard for drinking water installations

VDI*-Guide 6023 (2006): hygiene-conscious planning, construction, operation and maintenance of drinking water heating systems

DVGW** W 551 (2004): Drinking water heating and distribution system, technical measures for limiting growth of legionella; planning, establishment, operation and redevelopment of drinking water installations

DVGW** W 553 (1998): Dimensioning of central warm water circulation systems

* VDI: Society of German Engineers**DVGW: German Technical and Scientific Association for Gas and Water

Recommendation of the Federal Environmental Agency (FEA)

Dr. K. Luden

Categories of facilities that have to be monitored

1) Hospitals and nursing facilities (geriatric homes, nursing homes, baby-nursery)

2) Facilities for ambulant surgery, dialysis, rehabilitation...

3) Schools, Kindergarten

4) Hotels, youth hostels

5) Other training facilities, homes, holiday camps etc.

6) Sports facilities

7) Community accommodations

Recommendation of the Federal Environmental Agency (FEA)

Dr. K. Luden

In addition to W551:

In Facilities of category 1 and 2 (Hospitals, nursing facilities) no orientating investigation but always extensive investigation

Additional sampling in units with high risk (e.g. intensive care units)

Facilities with many division ranks (Teilstränge) sampling has to be conducted in units were showers are used

Parametric values

Dr. K. Luden

No recommendation by authorities because:

Little or no data on the correlation between Legionella concentration in water and infection rates

Legionella are not normally distributed in water (biofilms, amoeba)

? Should a domestic warm water distribution system that is up to date not be free of Legionella?Detecting 500 CFU/100 ml one day can result in 5.000 or 500.000 the other day.

W551

Dr. K. Luden

LegionellaCFU/100ml

Level of contamination

measuresFurther

investigationFollow up

> 10.000 extremely high Direct clearance measures (disinfection, prohibition of use) remediation necessary

Instantaneous 1 week after disinfection or remediation

> 1.000 High Remediation depends on outcome of further investigation

Immediately

100 Middle None Within 4 weeks

< 100 Low/no None None After 1 year

Assessment of the results of a routine monitoring (orientating 1x a year)

Lower Saxony

Dr. K. Luden

Sampling point

Water body to be checked during monitoring

Verteiler

Zulauf

1 2 i

2) LS1-LSi Steigstrang

1) L1 Austritt Trinkwassererwärmer

3) L3 Rücklauf Zirkulationsleitung

1 2 i

Technical survey and inspection of the distribution system always first (checklist provided with the recommendation)

Negative results of Legionella samples are no proof of a technically correct system

Sampling

Dr. K. Luden

Specifications:

L1 sampling at maximum temperature, document sampling temperature

LS run off exactly 1 liter of water, take sample, document sampling temperature, flush to maximum temperature, document temperature

L3 flush shortly to sample circulating water, document temperature

Follow instructions of ISO 19458 purpose b.

Sampling - ISO 19458

Dr. K. Luden

Purpose QualityRemove attached

devices and insertsDisinfect flush

a In the main Yes Yes Yes

bAs it reaches

the tapYes Yes

Noa

(miminal)

cAs

consumedNo No No

a flush shortly only to overcome influence of disinfection of the tap

Detection of systemic contamination: purpose b

Sampling - ISO 19458

Dr. K. Luden

Purpose QualityRemove attached

devices and insertsDisinfect flush

a In the main Yes Yes Yes

bAs it reaches

the tapYes Yes

Noa

(miminal)

cAs

consumedNo No No

a flush shortly only to overcome influence of disinfection of the tap

Risk assessment or case related investigation: purpose C

Dr. K. Luden

Water sample

Direct plating Membrane filtration

0.5 ml GVPC

0.5 mlGVPC

20 mlGVPC

100 mlGVPC

Incubationat 36 ± 2°C

for 7-10 days

Incubationat 36 ± 2°C

for 7-10 days

Incubationat 36 ± 2°C

for 7-10 days

Incubationat 36 ± 2°C

for 7-10 days

Subcultureconfirmation

Subcultureconfirmation

Subcultureconfirmation

Subcultureconfirmation

Detection method - ISO 11731

optional

Dr. K. Luden

Detection method - ISO 11731

Range of measurement:

1) Plating of 2x 0.5 ml → < 100 to 40.000 CFU/100 mlwith a maximum of 200 colonies per plate in accordance with ISO 8199

2) Membrane filtration of 20 ml → < 5 to 500 CFU/100 mlwith a maximum of 100 CFU/filter

Total of < 5 to 40.000 CFU/100 ml

Dr. K. Luden

Results 2005

Legionella[n]

Samples[n]

Assessment by W551

total 2637

< 5 1873 No / low contamination

5 764 Low contamination

> 10 644 Low contamination

> 100 409 Middle mid term remediation

> 1.000 149 High cont. short term remediation

> 10.000 42 Extremely high cont. imediate action

> 100.000 1 Extremely high cont. imediate action

Dr. K. Luden

Consequences Facilities with samples that show extremely high

contamination with Legionella might be asked to take action immediately.

Operators of house installations with medium contamination are asked to provide a mid term remediation plan.

Advice is offered and sometimes facilities are closed e.g. showers at a public swimming pool as a safety measure to public health.

NO concrete action is ordered by the public health services. The responsibility for providing safe water lies with the operator of the house installation.

Concluding remarks

Dr. K. Luden

Sampling and evaluation of Legionella detection in house installations has been harmonized in Lower Saxony.

Consulting of Public health services and operators of house installations contaminated by Legionella has become easier.

Sampling techniques fit the purpose of the monitoring.

If the recommended protocol is used and all temperatures are documented a first step towards finding the cause of the problem often is taken.

Although technical standards have been existing for more than 20 years facilities prevail that are not at the state of the art.