The PCV-13 vaccine may increase the susceptibility of antibiotic-resistant bacteria strains

A community-based study in Vietnam found a high percent of children under five years of age were carrying pneumococcal bacteria in their noses and throats that were non-susceptible to commonly-used antibiotics. Of the strains tested, 18% were not susceptible to penicillin, 26% weren’t susceptible to cefotaxime, 76% were not susceptible to meropenem and 14% were not susceptible to all three nor to any of the “macrolide” drugs (e.g., erthromycin and azithromycin). However, 90% of the multi-drug resistant strains are serotypes that are in the 13-strain pneumococcal conjugate vaccine (PCV-13) and thus the introduction of a vaccine is expected to increase the susceptibility of circulating strains of the bacteria.