Bacterial coinfections often found in viral-associated hospitalizations
Approximately 40% of patients requiring hospitalization for respiratory viral infections also have bacterial coinfection, according to researchers from the University of Rochester and Rochester General Hospital in New York.
“The occurrence of staphylococcal and pneumococcal pneumonia complicating influenza pandemics is well recognized,” the researchers wrote in the Journal of Infectious Diseases. “Although temporal associations between bacterial pneumonia and seasonal respiratory viruses have been reported, there is little specific data on the risk of bacterial complications of seasonal influenza and other virus infections.”
The researchers conducted a study that included all adults aged at least 21 years who were admitted to the ED with suspected acute respiratory tract infection from Nov. 1 to May 30 in the 2008, 2009 and 2010 winter seasons. Of the 842 hospitalizations evaluated, 348 had evidence of viral infection by polymerase chain reaction or serology. The most common virus was influenza A.
Among those with viral infection, 212 had viral infection alone and 136 had a mixed viral-bacterial infection. For those with mixed viral-bacterial infections, 33 had positive bacterial tests and elevated procalcitonin levels, 31 had only positive bacterial tests and 72 had elevated procalcitonin alone.
On multivariate analysis, the following features were predictive of mixed viral-bacterial infection: peripheral white blood cell count >12,000 (OR=3.8); anion gap (OR=1.2 per unit change); presence of chronic obstructive pulmonary disease (OR=2.9); chronic renal failure (OR=10.7); and infiltrate on chest radiograph (OR=2.5). Severity of illness scores was higher among those with mixed viral-bacterial infection.
Among those with viral infection alone, 90% were treated with antibiotics vs. 92% of those with mixed viral-bacterial infection, but those with bacterial infection were treated longer.
“Patients with positive viral testing should be carefully evaluated for concomitant bacterial infection, and it is prudent to initiate early empiric antibiotics for patients with severe viral illness or definitive radiographic pneumonia,” the researchers wrote. “At the present time, establishing a specific bacterial diagnosis using traditional methods remains difficult and better bacterial diagnostics are needed.”
Disclosure: The researchers report no relevant financial disclosures.