Emergence of 19A as Virulent and Multidrug Resistant Pneumococcus in Massachusetts Following Universal Immunization of Infants With Pneumococcal Conjugate Vaccine

Abstract

Three years after the introduction of pneumococcal conjugate vaccine for universal administration to children less than 2 in Massachusetts, a significant increase in invasive disease due to serotype 19A was observed. Although MLST 199 remains the most frequent sequence type among invasive isolates (of 19A), a multidrug-resistant sequence type, not previously identified in Massachusetts, has become an important cause of invasive disease. Further surveillance of the changing ecology of S. pneumoniae is necessary as a 4-year time period is not sufficient to fully evaluate the impact of PCV of pneumococcal infections.

Changing trends in serotype distribution and antimicrobial susceptibility ofStreptococcus pneumoniaecausing invasive diseases in Central Thailand, 2009–2012

“…[10][11][12] The emergent serotype 19A was associated with a higher rate of penicillin nonsusceptibity. [13][14][15] Other non-vaccine serotype have been identified to increase penicillin nonsusceptibility of invasive pneumococci in the post PCV7 era. Of these serotypes, 15A, 23A, 35B, and 6C were the most common among penicillin-nonsusceptible isolates from population-based invasive pneumococcal surveillance in the United States during 2007.…”

Infección neumocóccica invasora y neumonía consolidante en lactantes: Un año de vigilancia en tres centros hospitalarios chilenos

“…Además, se ha observado una importante reducción en la resistencia antimicrobiana de las cepas aisladas 11,23 así como una disminución en las hospitalizaciones por neumonías en niños vacunados 21,24 . Al mismo tiempo, se ha observado la emergencia de infecciones causadas por serotipos no incluidos en la vacuna 25 , situación que continúa en estrecha observación.…”

Pneumococcal vaccination: time to move on?

“…The 'Center for Disease Control' and several groups have documented that the number of pneumococcal infections caused by non PCV7 vaccine serotypes is increasing, primarily serotype 19A [3,9,13,15,16,18,19]. Moreover, multidrug antibiotic resistance among the 19A serotype isolates has become a major concern [13][14][15][16].…”