The rarity of serotype 19A among invasive pneumococcal disease (IPD) supported choice of PCV-10 for Bangladesh’s program. However, concern remains about emergence of this serotype, particularly multi-drug resistant (MDR) sequence type (ST) 320, after widespread PCV10 use. Therefore, we tracked the molecular epidemiology of 19A among pneumococci from Bangladeshi children over time.
We analyzed 64 isolates (54 pre-PCV and 10 post-PCV) spanning 2005-2018; isolates were from IPD (n=23), carriage (n=23) and otitis media (n=18). Isolates were subjected to whole genome sequencing and STs determined. Antimicrobial resistance patterns were determined phenotypically and genotypically.
Overall, a total of 24 STs were identified, including 3 novel STs. Among the identified STs, ST12473 (16.4%), ST2464 (16.4%) and ST12891 (11.5%) were most common. No ST320 strains were detected. Multidrug resistance (erythromycin, co-trimoxazole and tetracycline) was only seen in ST12473. In addition, ST2464 was predominantly non-susceptible to co-trimoxazole and tetracycline.
The surveillance identified two drug resistant STs but not ST320. However, considering the increased rate of serotype 19A seen elsewhere following PCV7 and PCV10 use, we should continue surveillance and molecular investigation of this serotype.