Legionella Pneumophila Pneumonia Clinical Trial
Official title:
The Impact of Legionella Urine Antigen Testing (LUAT) on the Local Epidemiology and Diagnosis of Legionella Pneumonia - A Hospital Based Study in Malaysia
There has never been a paper published or research done to determine the rate of Legionella species as a cause of community or nosocomial acquired pneumonia requiring hospitalization in Malaysia. Anecdotally, Legionnaires' disease is thought to be uncommon in Malaysia. This is one of the first prospective hospital-based studies to comprehensively evaluate the epidemiological and demographical factors of patients hospitalized with Legionella infection in Malaysia.
Legionellosis is an environment-related, acute gram negative bacterial respiratory infection
and is caused primarily by the species Legionella pneumophila, an atypical pulmonary
pathogen, in the likes of mycoplasma and chlamydia species. Potentially all Legionella spp.
may cause human disease, however, the majority (92%) of clinical cases are caused by L.
pneumophila and the predominant serogroup is serogroup 1.
Globally, 1-5% of community acquired pneumonia patients is caused by Legionella spp. and is a
challenge to public health authorities. The incidence of Legionella Pneumonia in the US has
exceeded expectations and is increasing, with at least 13,000 cases occurring annually. In
Singapore, Legionella spp. is responsible for 2-7% of cases of hospitalized
community-acquired pneumonia.
Legionella pneumophila is being increasingly recognized as a common pathogen causing both
community-acquired and nosocomial pneumonia that is responsible for significant morbidity and
mortality. It is also one of the most common aetiology discovered when pneumonia is
sufficiently severe to require admission to an intensive care unit. It's likely to cause a
severe form of pneumonia with high likelihood of adverse medical outcomes which includes
rapid deterioration, respiratory failure and the need for intensive care unit (ICU)
admission.
It will be impossible to distinguish patients with Legionnaires' disease from patients with
other types of pneumonia clinically. The key to diagnosis is to perform microbiologic testing
when a patient is stratified into a high-risk category. Rapid diagnosis of these pneumonias
is desired as delayed diagnosis and institution of appropriate antibiotics is associated with
poor outcomes.
In routine clinical practice, legionellosis is rarely proven by culture whereas detection of
urinary antigen is now common. In US and Europe, case detection rates were revolutionized
with the usage of urine antigen test at 97% and 79% respectively. Urine antigen testing has a
reported sensitivity that ranges between 76% and 86% for cases of Legionella pneumonia
serogroup 1 and a specificity that approaches 100%.
In this region, urine antigen test is rarely done due to lack of clinical awareness, a
perception that Legionella infection is uncommon and due to the lack of availability of this
test regionally. The introduction of the immunochromatographic (ICT) membrane assay to detect
antigenuria has revolutionized the usage of UAT to diagnose Legionella infections. The ICT
assay is similar to a home pregnancy test and is commercially available. The test is simple
to perform and does not require special laboratory equipment, and results can be obtained
within 15 minutes. The investigators wish to utilize this innovation to test patients whom
are hospitalized with pneumonia and determine the incidence of Legionella infection in the
local setting.
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