Inhaled corticosteroids increase Staphylococcus pneumoniae infection risk

By Helen Albert, Senior medwireNews Reporter

Regular use of inhaled corticosteroids (ICS) by asthmatic children increases their risk for oropharyngeal colonization with Staphylococcus pneumoniae almost fourfold, research suggests.

"These findings highlight the need for further studies to investigate the possible link between ICS and risk of respiratory infections in these patients," write Linjie Zhang (Federal University of Rio Grande, Brazil) and colleagues in Respirology.

Zhang and team recruited 200 consecutive patients with asthma (aged up to 18 years), 192 of whom were included in the analysis. Of these, 96 were exposed to ICS with a mean daily dose of 400 mcg of ICS for 8.6 months on average, and 96, who were age-matched to the exposed patients, had asthma but were not treated with ICS.

The researchers found that oropharyngeal colonization with S. pneumoniae was significantly more frequent in the group exposed to ICS than in the nonexposed group, at 27.1% versus 8.3%.

Following adjustment for factors such as gender, ethnicity, household size, number of siblings, maternal smoking, antibiotic use in the past 3 months, hospitalization in the past 6 months, and vaccination against S. pneumoniae, regular use of ICS increased the risk for S. pneumoniae colonization by a significant 3.75-fold.

Overall, 26 strains of S. pneumoniae were cultured from the exposed and eight from the non-ICS-exposed patient samples. Notably, 26.9% of the exposed samples were resistant to penicillin compared with 12.5% of the nonexposed group.

"Taken together, we postulate that a higher carriage rate of S. pneumoniae in the oropharynx, along with impaired airway clearance may increase the risk of having pneumococcal respiratory infections in children with persistent asthma receiving regular ICS," suggest the authors.

Although "further larger prospective studies are needed to better define the relationship between ICS therapy, oropharyngeal colonization by potential respiratory pathogens and clinical outcomes of these patients," they concede.

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