INVASIVE STREPTOCOCCUS PNEUMONIAE SEROTYPE 19A IN THAILAND (2008-2018)

Following introduction of a 7-valent pneumococcal polysaccharide-protein conjugate vaccine (PCV7), incidences of invasive pneumococcal disease caused by Streptococcus pneumoniae serotype 19A non-susceptible penicillin dramatically increase worldwide. In Thailand, as molecular characterization of invasive S. pneumoniae serotype 19A is sparse, we determined multilocus sequence types (MLSTs) and antibiogram profile of invasive disease serotype 19A isolated from 21 hospitals during 2008-2018. S. pneumoniae (n = 62) demonstrated twenty different STs, grouped into three main clonal complexes (CCs), namely, CC63 (36%), CC230 (21%) and CC320 (43%), with the most predominant MLST being ST320 (n = 25), followed by ST2930 (n = 9), ST230 (n = 7), ST63 (n = 3), ST95 and ST8346 (n = 2 each); there were also seven isolates having novel STs (14415, 14391, 14392, 14389, 14390, 14413, and 14414). Based on criteria for meningitis, 93 and 52% of isolates were non-susceptible to penicillin and cefotaxime/ceftriaxone, respectively while 30 and 8% of non-meningitis isolates were non-susceptible, respectively. Non-susceptibility to meropenem and erythromycin constituted 72% of the isolates while 100% were susceptible to levofloxacin, ofloxacin and vancomycin. The predominant ST320 and ST2930 isolates were multidrug resistant (ie, resistant to at least three classes of antimicrobial) and were disseminated among the study hospitals during the survey period. Hence, control and prevention of infection by highly antimicrobial-resistant S. pneumoniae serotype 19A should be a major health care concern.