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In Our Opinion includes articles and information we highlight as well as commentary on published peer-reviewed articles and current topics.

One Experts Opinion: Yael Shachor-Meyouhas

Legionnaires' Disease in Children



Introduction

Legionella has not been a prominent pathogen in children with pneumonia. The discovery of Legionnaires' disease as a community-acquired pneumonia in immunocompetent (healthy) children occurred fortuitously. The diagnosis was made in two infants less than age 1 year with severe pneumonia when specialized Legionella tests were available because a study of Legionnaires' disease had been implemented for adults in the hospital assessing a new antibiotic for Legionnaires' disease (Famigilletti). This chance diagnosis raised the likelihood that legionellosis might be occurring in children but overlooked.

 

In 2008, the US Centers for Disease Control (CDC) published a report of increasing incidence of Legionnaires' disease in USA. Of the 23,076 cases reported between 1990 and 2005, only 375 cases (1.7%) were pediatric cases, most reported  cases were in children 15-19 years old (44.3%) and in infants less than one year (18.1%). In a 2006 review summarizing 76 reported cases of legionellosis in children, 19% were below the age of 2 months, 19% were infants (age 2-12 months) and 62% were children (age 1 to 18 years). 

 

Hospital - acquired Legionnaires' disease

 

In a CDC survey of pediatric Legionellosis, 72% of cases were hospital-acquired, i.e. the disease was contracted after the child was admitted to the hospital for other medical problems (Alexander NT, ICAAC 2008). This may result from biased case detection in that the disease may be suspected more easily in hospitalized patients since obscure causes are often considered in immunosuppressed patients and diagnostic tests for Legionnaires' disease are applied.When compared to children in the community, children with hospital-acquired Legionnaires' disease were sicker and experienced higher mortality (41%vs. 23%). The source of the infection was the hospital water supply in 88% of cases when environmental cultures of the hospital water were performed. 

 

We reported an eleven days old boy who presented with shortness of breath and an abnormal chest x-ray. L. pneumophila identified by both culture and PCR (a molecular test) from the trachea and lung autopsy (Shachor-Meyouhas PIDJ 2010). The source of the Legionella was the hospital tap water.

 

Two hospital-acquired cases were reported in infants who underwent "water birth" delivery in which the mother's labor and delivery are performed in warm bath water. Tap water is used at a temperature of 37oC - an ideal growth temperature for Legionella. In both cases, Legionella was also isolated from the water used in the water bath.  Aspiration was the presumed mode of transmission. Aspiration is a process whereby water enters the lung during inhalation.

 

When to suspect Legionnaires' disease in a child?

The clinical familiarity of pediatricians with Legionellosis is lacking, such that this infection is usually not considered in children with pneumonia. As a result, antibiotic therapy effective against Legionella is often not prescribed.

 

Correct antibiotic therapy is critical in maximizing survival. In the 2006 review, mortality was 23% for those who received correct therapy vs. 70% for those who did not. 

 

The most important clinical clue may be persistence of fever and respiratory symptoms in children despite receiving beta-lactam antibiotics (which is inactive against Legionella) and progression of pneumonia.

 

Clues to the diagnosis which have proven useful in adults might be applied to children including:

  • Clinical: Pneumonia accompanied by diarrhea and vomiting. These symptoms may be less prominent in children compared to adults
  • Laboratory abnormalities: The Gram stain of sputum: a staining test which shows bacterium. Low salt (hyponatremia) (although this finding may be less common in children) and abnormal liver tests

 

Can the outcome for pediatric legionellosis be improved?

US CDC has recommended that Legionella be considered as a cause for pediatric pneumonia (Alexander ICAAC 2008) but this recommendation has been generally ignored. Focusing on patients at highest risk may be a fruitful strategy. We recommend that hospitals that care for children routinely culture the hospital water supply for Legionella as is done for adult hospitals throughout Israel Europe and U.S. It is not a coincidence that the first recognized outbreaks of pediatric Legionnaires' disease occurred in hospitals which the adults had already experienced such outbreaks of Legionnaires' disease (Ohio State, University of Pittsburgh, Stanford University). Specialized laboratory methodology for Legionella available for adults was then available for diagnosis in children with pneumonia. 

 

Conclusion

So, as to minimize suffering and mortality among vulnerable children, we recommend:

  • A high index of suspicion for Legionnaires' disease should be exercised by physicians especially in hospitalized immunocompromised children or children with severe pneumonia who fail to respond to standard antibiotic therapy.
  • All hospitals specializing in care for children should culture the tap water of the hospital. This is a proactive preventive approach that has been widely adopted in Europe and Israel. In the U.S., culture of hospital water as a proactive measure has been adopted in Maryland and New York, the US Veterans Affairs Healthcare System, and in most US hospitals performing organ transplantation. Tap water of hospital units housing high-risk children can be targeted, including transplant units and intensive care units.

 

 

References

  1. Greenberg D, Chiou CC, Famigilleti R, Lee TC, Yu VL. Problem pathogens: paediatric legionellosis-implications for improved diagnosis. Lancet Infect Dis 2006;6:529-35
  2. Unit for Surveillance and Control of Communicable Diseases. Legionnaires disease in a neonatal unit of a Private hospital, Cyprus, December 2008: Preliminary outbreak report. Euro Surveill 2009 Jan 15; 14(2).Pii 19090
  3. Neil K, Berkelman R. Increasing Incidence of Legionellosis in the United States, 1990-2005: Changing Epidemiologic Trends. Clin Infect Dis 2008; 47:591-9
  4. Shachor-Meyouhas Y, Kassis I, Bamberger E, Nativ T, Sprecher H, Levy I, Srugo I. Fatal hospital-acquired Legionella pneumonia in a neonate. Pediatr Infect Dis J. 2010 Mar;29(3):280-1.
  5.  Yu VL, Lee TC. Neonatal legionellosis: the tip of the iceberg for pediatric hospital-acquired pneumonia? Pediatr Infect Dis J. 2010 Mar;29(3):282-4.
  6. Alexander NT, Fields BS, Hicks LA. Epidemiology of reported pediatric legionnaires' disease in the United States, 1980-2004. Presented at 48thInterscience Conference on Antimicrobial Agents and Chemotherapy ;2008: Washington D.C. Abstract #G1-1694.
  7. Neil K, Berkelman R. Increasing Incidence of Legionellosis in the United States, 1990-2005: Changing Epidemiologic Trends. Clin Infect Dis 2008; 47:591-9
  8. Famiglietti RF, Bakerman PR, Saubolle MA, Rudinsky M.  Cavitary legionellosis in two immunocompetent infants.  Pediatrics. 1997 Jun;99(6):899-903.
  9. Shachor-Meyouhas Y, Kassis I, Bamberger E, Nativ T, Sprecher H, Levy I, Srugo I. Fatal hospital-acquired Legionella pneumonia in a neonate.Pediatr Infect Dis J. 2010 Mar;29(3):280-1.

 


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