Common Bacteria that Causes Pneumonia Found To Be Rare in CF Patients

Researchers at the University of Calgary in Canada have recently published in the journal BMC Pulmonary Medicine findings indicating that lung colonization by the bacteria Streptococcus pneumonia is relatively rare in patients with cystic fibrosis (CF) and when present, it apparently does not have an adverse impact on patients’ clinical conditions. The study is entitled “Prevalence and impact of Streptococcus pneumonia in adult cystic fibrosis patients: a retrospective chart review and capsular serotyping study.”

CF is a life-threatening genetic disease in which a defective gene, called cystic fibrosis transmembrane conductance regulator (CFTR), causes the body to form unusually thick, sticky mucus that can result in serious respiratory and gastrointestinal manifestations. This thick, difficult to clear mucus can accumulate in the lungs, creating an environment prone to bacteria growth that can lead to severe infections.

Infection with Streptococcus pneumonia has rarely been associated with CF and the majority of the reports involve infant and pediatric populations. In the study, researchers conducted a retrospective analysis of a clinical and microbiologic database from a Canadian CF center – Adult Cystic Fibrosis Clinic of Southern Alberta – with data collected between 1978 and 2013, to assess the prevalence, incidence, serotype and clinical impact of Pneumococcus in a cohort of 318 adult CF patients.

Researchers found that in this cohort, Pneumococcus corresponded to less than 0.1% of the bacterial isolates in CF patients and that only 15 out of the 318 patients (5%) had transient Pneumococcus colonization. Ten different Pneumococcus serotypes were found among the isolates with no predominant pattern. The team tested the patients’ lung function at the time of Pneumococcus isolation, as well as prior and after it, and found that there was no significant decrease in lung function as evaluated by spirometry, neither an increase in the requirement for antibacterial therapy. None of the adult CF patients were found to develop persistent chronic infection.

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The research team concluded that in the Canadian adult CF patient cohort analyzed, incident Pneumococcus infection is relatively rare and it is not linked, as one would expect, to clinical deterioration of the patient neither to chronic infection. The team suggests that further studies should be conducted with a larger number of patients to assess the long-term effects of Pneumococcus colonization in the lungs of CF patients.