Moraxella Species Bacteremia in Cancer Patients: A Case Series and Review of the Literature

Moraxella is a genus of gram-negative diplococci considered to be an important cause of upper respiratory tract disease in humans. Bacteremia caused by Moraxella species, however, remains rare and tends to occur in individuals with a compromised immune system. We reviewed all cultures positive for Moraxella species at an academic cancer hospital between the years of 2011 and 2016. We also performed a literature review of Moraxella species bacteremia in cancer patients in the decade between 2006 and 2016. At the H. Lee Moffitt Cancer Center, between 2011 and 2016, there were 41 positive cultures (from all sites) for Moraxella species. Of these 41 cultures, only 3 were positive blood cultures. Our findings indicate that bacteremia caused by Moraxella species can range in severity from fever and chills to frank sepsis. As has been noted in other publications, the source of the bacteremia is not always clinically apparent, but upper and lower respiratory sources seem to predominate. None of the patients presented in this case series died of their bacteremia. The 2 publications discovered in our literature review similarly describe 2 nonfatal cases of Moraxella osloensis bacteremia: 1 case in a patient with a recent diagnosis of acute myeloid leukemia and 1 case in a patient with an unspecified lung cancer.