Legionnaires' disease (LD) is a serious sometimes fatal pneumonia caused by Legionella pneumophila. The clinical manifestations of LD may be similar to those by caused by Streptococcus pneumoniae. As both conditions can be serious illnesses but requiring different antimicrobial therapies, factors that can help differentiate these types of pneumonias can be helpful in the clinical management of hospitalized patients with bacterial pneumonia. This study aimed to compare clinical features and indicators of disease progression in hospitalized patients with community-acquired pneumonia caused by L. pneumophila and bacteremic S. pneumoniae.
We conducted a retrospective case comparison study of adult patients hospitalized with LD or S. pneumoniae. Data collected included demographic, clinical characteristics, and comorbidities, and outcomes. Data were analyzed using SPS vs 24.0. Multivariable analysis was done using logistic regression with a forward stepwise algorithm.
A total of 106 patients met study criteria. The incidence of LD peaked in summer months and S. pneumoniae peaked in the winter quarter. From multivariable analysis predictors of LD were male gender (OR=21.6, p < 0.001), diarrhea (OR=4.5, p = 0.04), body mass index (BMI) (OR=1.13, p = 0.02), hyponatremia (OR=5.6, p = 0.03 and Charlson weighted index of comorbidity (CWIC) score (OR=0.61, p = 0.01). Patients with S. pneumoniae had higher rates of mechanical ventilation, septic shock, and death than those with LD.
Our data suggests that variables that may distinguish LD from S. pneumoniae include male gender, diarrhea, hyponatremia, higher temperature on admission, higher BMI and fewer comorbidities. Bacteremic S. pneumoniae was associated with poorer outcomes than LD including higher rates of septic shock, mechanical ventilation, ICU admission, and death.
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- Legionnaires’ disease: description of an epidemic of pneumonia.N Engl J Med. 1977; 297: 1189-1197
- Estimate of burden and direct healthcare cost of infectious waterborne disease in the United States.Emerg Infect Dis. 2021; 27: 140-149
- Active Bacterial Core surveillance for legionellosis–United States, 2011–2013.MMWR Morb Mortal Wkly Rep. 2015; 64: 1190-1193
- Increasing incidence of legionellosis in the United States, 1990-2005: changing epidemiologic trends.Clin Infect Dis. 2008; 47 (PubMed.): 591-599
Centers for Disease Control and Prevention. Legionnaires' Disease and Pontiac Fever. History and Disease Patterns. https://www.cdc.gov/legionella/about/history.html.
- Legionnaires'disease: report of sixty-five nosocomially acquired cases and review of the literature.Medicine (Baltimore). 1980; 59: 188-205
- Rapid diagnosis of legionnaires’ disease using an immunochromatographic assay for legionella pneumophila serogroup 1 antigen in urine during an outbreak in the Netherlands.J Clinic Microbiol. 2000; 38: 2738-2739
- A new method of classifying prognostic comorbidity in longitudinal studies: development and validation.J Chronic Diseases. 1987; 40: 373-383
- The compromised host and Legionnaires.Dis Ann Internal Med. 1979; 90: 533-537
- Community-acquired pneumonia requiring hospitalization among US adults.N Engl J Med. 2015; 373: 415-427
- Evaluation of the Winthrop-University Hospital criteria to identify Legionella pneumonia.Chest. 2001; 120: 1064-1071
- Legionnaires’ disease: a rational approach to therapy.J Antimicrob Chemother. 2003; 51: 1119-1129
- Clinical characterization of pneumonia caused by atypical pathogens combining classic and novel predictors.Clin Microbiol Infect. 2007; 13: 153-161
- Clinical study of an outbreak of Legionnaire's disease in Alcoy, Southeastern Spain.Eur J Clin Microbiol Infect Dis. 2002; 21: 729-735
- Can legionnaires disease be diagnosed by clinical criteria?.Chest. 2001; 120: 1049-1053
- Trends in legionnairesdisease, 1980-1998: declining mortality and new patternsof diagnosis.Clin Infect Dis. 2002; 35: 1039-1046
- Sporadic andepidemic community legionellosis: two faces of the same illness.Eur Respir J. 2007; 29: 138-142
- Community-acquired Legionella pneumophila pneumonia: a single-center experience with 214 hospitalized sporadic cases over 15 years.Medicine (Baltimore). 2013; 92 (PMID: 23266795; PMCID: PMC5348137): 51-60https://doi.org/10.1097/MD.0b013e31827f6104
- Active Bacterial Core Surveillance for Legionellosis - United States, 2011-2013.MMWR Morb Mortal Wkly Rep. 2015; 64 (PMID: 26513329): 1190-1193https://doi.org/10.15585/mmwr.mm6442a2
Published online: March 10, 2022
Accepted: February 28, 2022
Received: September 21, 2021
© 2022 Published by Elsevier Inc. on behalf of Southern Society for Clinical Investigation.