Aug
20
2015
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The Importance of Legionella Testing in Light of the Recent Legionnaires’ Disease Outbreak in the South Bronx and Legislative Implications

by Jules Zacher, Esquire, Tawny Vu, MPH

Legionella_Plate_01

I.  Introduction

Bronx, New York is currently experiencing its second outbreak of Legionnaires’ disease within an eight-month time period.  The second most recent outbreak occurred in December 2014, and the current outbreak began mid-July of this year.  In a recent news report, Bronx Borough President Ruben Diaz, Jr. calls for legislation that would compel repeat inspections of cooling towers.1  This paper will emphasize the importance of testing for Legionella bacteria and discuss why Diaz’s legislative response, while admirable, is inadequate for the needs of the Bronx.

The press release issued by Mr. Diaz states that he will call for an inspection system “for coolant systems, rooftop water tanks and other standing water infrastructure that could be a breeding ground for this disease and others.”  He goes on to say that “The city must create a new inspection system for these systems, just as we inspect other critical systems such as elevators.”2  While Diaz’s call for mandatory inspections is commendable, it does not seem to require testing or sampling of the water in these cooling towers for the presence of Legionella bacteria, the cause for the recent 86 cases of Legionnaires’ disease and seven deaths in South Bronx.  Any legislation passed by the New York City Council should contain such a requirement in all large facilities to truly make an impact.

II.  Current Outbreak

According to recent news reports, seven people have died from Legionnaires’ disease, with 86 people contracting the disease of which at least 57 have been hospitalized.  An investigation by the New York City Department of Health and Mental Hygiene has revealed that five cooling towers in various buildings within a 20-square-block area in the South Bronx tested positive for the presence of the Legionella bacteria that causes the disease.3  The health department is expecting additional people to present with Legionnaires’ disease as they may have been exposed prior remedial efforts.

III.  Calls for Legislation

Bronx Borough President Ruben Diaz, Jr. has called for regular inspections of cooling towers, which is the suspected source of current outbreak.  Unfortunately, simply inspecting cooling towers without regularly sampling for the presence of Legionella is insufficient.

A variety of elements can fall under the term “inspection,” i.e. records of system maintenance, water treatment, and system shut-down and start-up.  While all of these are important indicators of the state of cooling towers and evaporative condensers, they do not verify the final effect, i.e. the presence of Legionella bacteria at dangerous concentrations in the cooling tower and/or potable water systems.  This information can only be ascertained by sampling and testing for the presence of the bacteria.  Only verification through regular testing can cooling towers and potable water systems be considered safe to be among the public.

IV.  Recent ASHRAE Guidelines

             The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recently approved a standard for managing water systems to prevent the buildup of the Legionella bacteria, ANSI/ASHRAE 188-2015 Legionellosis: Risk Management for Building Water Systems.4  Section 7.2 of this standard deals with cooling towers and evaporative condensers.  Nowhere in the standard, however, is there a requirement for sampling for the presence of Legionella.  Rather, the standard deals with “preventive measures,” including equipment siting, new-system start-up, system maintenance, and water treatment to control microbiological activity, scale and corrosion.5

ASHRAE’s reasoning for not requiring sampling is found in an older ASHRAE document, ASHRAE 12-2000.  As stated, “…routine culturing of samples from building water systems may not be predictive of the risk of transmission…”6  The ASHRAE 12-2000 guideline then goes on to cite four reasons for making this conclusion.

The first reason is that “presence of the organism cannot be directly equated to the risk of infection”.7  While this is true, unsuspecting victims will contract Legionnaires’ disease if the Legionella levels reach dangerous concentrations as a result of improper water maintenance on the part the building or cooling tower owner.  While proper preventive measures may be able to control the bacteria, there is no way to ensure these preventative measures are working unless sampling and testing are performed to confirm bacteria levels.

The second reason provided by ASHRAE is “Interpretation of the results of culturing of water is confounded by use of different bacteriological methods in various laboratories, by variable culture results among sites sampled within a water system, and by fluctuations in concentration of Legionella isolated from a single site.”8 There are currently numerous labs around the country that have been certified by the CDC Environmental Legionella Isolation Techniques Evaluation (ELITE) Program to be authorized to analyze samples for Legionella.  These labs are more than adequate to determine if a sample has Legionella as they have been certified by a government entity. It is admitted that sampling often reveals Legionella in one location of a building and not another, as well as differing concentrations of the bacteria in the building or cooling tower and plumbing systems.  Do either of these findings deny that Legionella exists in the building or its various water systems?  Hardly.

The third reason given is “The risk of illness following exposure to a given source is influenced by a number of factors other than the concentrations of organisms in the sample.  These factors include but are not limited to strain virulence, host susceptibility, and how efficiently the organisms are aerosolized …”.9  While it is true these factors play a role in whether someone contracts the disease, emphasis on the victim is misplaced.  Whether a person is more or less susceptible shifts the burden to the victim and not the perpetrator.

The strain virulence is another red herring.  Doctors treating patients with the disease are not concerned with the virulence of the source bacteria; they only know they have a sick patient.  Regardless of the virulence of a strain of bacteria, the concentration was sufficient for infection.  In addition, aerosolization of the bacteria may not be an issue at all as some experts have stated the disease is caused by aspiration rather that inhalation of the disease.10

The final reason given by ASHRAE for not routine culturing of the water is “Test results only represent the counts at the time the sample was collected.  A negative result from such a sample is likely to lead to a false sense of security because any amplifier can quickly become heavily colonized if it suffers neglect.”11

The focus here needs to be shifted to regular testing for Legionella in addition to regular maintenance methods.  If testing were done on a regular basis, a false sense of security would not be a problem as a baseline for Legionella levels would be provided12.  Testing for Legionella is important in determining whether or not adjustments need to be made to maintenance plans in order to protect the public.

V.  Conclusion

No doubt there will be pressure on legislators, such as Mr. Diaz, not to include a requirement for sampling in any proposed legislation dealing with the recent outbreak in the Bronx.  Industries such as hotels and electric generation will certainly weigh in on the subject because once they find the bacteria they must take some corrective action. These lobbyists will most likely point to the recent ANSI/ASHRAE 188-2015 discussed above as justification to not include sampling.  The reasons stated by ASHRAE, however, do not hold up.

It is incumbent on our legislators, therefore, not to succumb to this pressure.  Legionnaires’ disease is an entirely preventable illness and so preventative action is the key.  Only mandatory testing on a regular basis for the presence of Legionella in cooling towers and plumbing systems will prevent the next outbreak of Legionnaires’ disease.

Footnotes

1 Benjamin Mueller, “Unease Spreads in Bronx as Disease Claims 4th Life”, NYT, August 4, 2105, p. 4

2 Website of Ruben Diaz, Jr http://bronxboropres.nyc.gov/

3 Ibid, Benjamin Mueller, “Unease Spreads in Bronx as Disease Claims 4th Life”, NYT, August 4, 2105, p. 4

4 “Legionellosis: Risk Management for Building Water Systems”, ANSI?ASHRAE Standard 188-2015, American National Standards Institute, June 26, 2015

5 Ibid, “Legionellosis: Risk Management for Building Water Systems”, ANSI/ASHRAE Standard 188-2015, American National Standards Institute, June 26, 2015, p. 7

6 “Minimizing the Risk of Legionellosis Associated with Building Water Systems”, ASHRAE Guideline 12-2000, ASHRSAE, February 10, 2000, p. 13

7 Ibid, “Minimizing the Risk of Legionellosis Associated with Building Water Systems”, ASHRAE Guideline 12-2000, ASHRSAE, February 10, 2000, p. 13

8 Ibid, “Minimizing the Risk of Legionellosis Associated with Building Water Systems”, ASHRAE Guideline 12-2000, ASHRSAE, February 10, 2000, p. 13

9 Ibid, “Minimizing the Risk of Legionellosis Associated with Building Water Systems”, ASHRAE Guideline 12-2000, ASHRSAE, February 10, 2000, p. 13

10 Yu cita

11 bid, “Minimizing the Risk of Legionellosis Associated with Building Water Systems”, ASHRAE Guideline 12-2000, ASHRSAE, February 10, 2000, p. 13

12 Carl B. Fliermans, Ph.D.  E-mail Correspondence of August 4-6, 2015.

 

Posted by jzacher">jzacher at 11:57 am

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