866. Frequency of Nasopharyngeal Colonization with Streptococcus pneumoniae in HIV-1-infected Adults
Session: Poster Abstract Session: Bacterial Infections: Pathogenesis and Immunity
Friday, October 9, 2015
Room: Poster Hall
Background: Streptococcus pneumoniae (Spn) is a common and serious cause of pneumonia, bacteremia, and meningitis among adults, particularly those with HIV-1 infection. Each syndrome is preceded by asymptomatic Spn nasopharyngeal (NP) and/or oropharyngeal (OP) colonization.  The frequency of Spncolonization among U.S. adults with and without HIV-1 infection is not well characterized in the era of consistent conjugate vaccination of children.

Methods: From March 2014-May 2015, we enrolled 138 HIV-1-infected (HIV+) and 93 uninfected controls aged 18-55 years without other underlying immunosuppression, lung disease, or antibiotic use within 3 months of enrollment.  NP and OP samples were collected using flocked swabs in Amies media.  NP samples were inoculated onto sheep’s blood agar ± gentamicin, incubated, and examined for alpha-hemolytic colonies susceptible to optochin and soluble in bile acids, findings diagnostic of Spn.  In parallel, we tested DNA extracted directly from the NP samples by quantitative PCR for total bacterial 16S rDNA and the Spn-specific lytA gene, detection of which under 40 cycles met molecular criteria for Spn.

Results: Among HIV+ subjects (mean 586 CD4+ T cells/µL, plasma HIV RNA 15,816 copies/mL), 78% were on ART and 79% had received pneumococcal vaccination. Overall, bacterial DNA was detectable in all samples. However, only 4% of HIV+ subjects and 3% of controls were colonized with Spn (not significant, p = 0.74).  5 subjects were positive by culture and lytAPCR, 4 by PCR alone.  The majority of colonized individuals were sampled during local influenza season. 3 of 6 colonized HIV-1-infected subjects had received 23-valent pneumococcal vaccine within 1-7 years pre-enrollment.

Conclusion:   Using rigorous culture dependent and independent methods, the frequency of colonization with Spn among adults (3-4%) was lower than previously reported in both HIV+ and control adults in the U.S. (9-14%).  These findings may be attributable to infrequent exposure to young children, high rates of pneumococcal vaccination in HIV+ subjects, and widespread vaccination of children in the community.  Future directions include analysis of OP samples for Spn by PCR, characterization of NP and OP microbiomes in the two groups, and monitoring the incidence of pneumococcal disease among HIV+ subjects in the community.

Lindsay Nicholson, MD1, Jennifer Kofonow, MS2, Timothy Wright, MA3, Edward M. Gardner, MD3, Edward N Janoff, MD, FIDSA4 and Daniel Frank, PhD5, (1)Internal Medicine/Infectious Diseases, University of Colorado Denver, Aurora, CO, (2)Infectious Diseases, University of Colorado Denver, Aurora, CO, (3)Denver Health and Hospital Authority, Denver, CO, (4)University of Colorado, Anschutz Medical Center, Aurora, CO, (5)Medicine, University of Colorado Denver School of Medicine, Aurora, CO


L. Nicholson, None

J. Kofonow, None

T. Wright, None

E. M. Gardner, None

E. N. Janoff, Merck vaccines: Consultant , Consulting fee
Pfizer: Research Contractor , Research support

D. Frank, None

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