Severity of H1N1 influenza linked to presence of Streptococcus pneumoniae

December 31, 2009, The Earth Institute at Columbia University

The presence of the Streptococcus pneumoniae in samples that can be easily obtained in clinics and emergency rooms may predict risk of severe disease in H1N1 pandemic influenza. Reports that H1N1 pandemic influenza in Argentina was associated with higher morbidity and mortality than in other countries led investigators in the Center for Infection and Immunity (CII) at the Mailman School of Public Health of Columbia University, their colleagues at Argentina's National Institute of Infectious Diseases (INEI), and Roche 454 Life Sciences to look for viral mutations indicative of increased virulence and for co-infections that could contribute to disease.

Complete genome sequencing of nasopharyngeal samples representing severe or mild disease revealed no evidence of evolution toward a more virulent phenotype or development of antiviral resistance. However, MassTag PCR, a method for sensitive, simultaneous surveillance and differential diagnosis of infectious diseases, found a strong correlation between the presence of Streptococcus pneumoniae and increased risk for severe disease. The findings, which suggest a new strategy for identifying and treating these patients, are currently online in the publication Plos One.

The scientists examined nasopharyngeal samples representing 199 cases of pandemic (H1N1pdm) infections from Argentina. The sample set included 39 cases classified as severe and 160 cases categorized as mild. "We used a combination of 454 pyrosequencing and classical Sanger sequencing methods to test for viral evolution toward increased virulence. Comparison of viral sequences from Argentina with those obtained from other parts of the world provided no clues to the increase in severity of disease," said Gustavo Palacios, PhD, assistant professor of epidemiology at CII, and a lead and corresponding author. "However, MassTag PCR allowed us to find a new risk factor, independent of obesity, asthma, diabetes or chronic illness. S. pneumoniae was present in the majority of severe cases."

Specimens were tested for the presence of 33 viral and bacterial respiratory pathogens. "The presence of in individuals between the age of 6 and 55, those most affected by the current pandemic, was associated with a 125-fold increased risk of severe disease," said Mady Hornig, MD, associate professor of epidemiology and a co-first author of the paper. "Whereas the association of S. pneumoniae with and had been established in current and previous influenza pandemics, this study is the first to demonstrate that the diagnosis of S. pneumoniae, when it is still actionable, might have an impact on clinical management."

"Three practical implications emerge from our study," said CII Director W. Ian Lipkin, MD, John Snow Professor of Epidemiology, and professor of Neurology and Pathology at Columbia University. "First, S. pneumoniae is important in the pathogenesis and prognosis of H1N1pdm-associated disease. Whether this effect is associated with all S. pneumoniae or only with specific serotypes remains to be determined. Second, easily accessible samples such as nasopharyngeal swab samples may be used as an index to risk of severe disease. Third, multiplex diagnostic methods like MassTag PCR can enable rapid detection of a broad spectrum of viral and bacterial agents and inform clinical care."

More information: To access the study findings: dx.plos.org/10.1371/journal.pone.0008540

Related Stories

Recommended for you

Scientists gain new insight on how antibodies interact with widespread respiratory virus

February 22, 2018
Scientists have found and characterized the activity of four antibodies produced by the human immune system that target an important protein found in respiratory syncytial virus (RSV), according to new research published ...

Study reveals how kidney disease happens

February 22, 2018
Monash researchers have solved a mystery, revealing how certain immune cells work together to instigate autoimmune kidney disease.

Past encounters with the flu shape vaccine response

February 20, 2018
New research on why the influenza vaccine was only modestly effective in recent years shows that immune history with the flu influences a person's response to the vaccine.

Building better tiny kidneys to test drugs and help people avoid dialysis

February 16, 2018
A free online kidney atlas built by USC researchers empowers stem cell scientists everywhere to generate more human-like tiny kidneys for testing new drugs and creating renal replacement therapies.

Expanding Hepatitis C testing to all adults is cost-effective and improves outcomes

February 16, 2018
According to a new study, screening all adults for hepatitis C (HCV) is a cost-effective way to improve clinical outcomes of HCV and identify more infected people compared to current recommendations. Using a simulation model, ...

Study suggests expanded range for emerging tick-borne disease

February 16, 2018
Human cases of Borrelia miyamotoi, a tick-borne infection with some similarities to Lyme disease, were discovered in the eastern United States less than a decade ago. Now new research led by the Yale School of Public Health ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.