The aim of this study was to determine the change in serotypes and antibiotic resistance of pneumococcal strains isolated from healthy nasopharyngeal carriers in children from Lima-Perú after introduction of Pneumococcal Conjugate Vaccine (PCV13).
This was a post-PCV13 observational study (2016 to 2019), in five hospitals in Lima-Perú. Nasopharyngeal swab from 1000 children <2 years was taken. We compare the data with previous pre-PCV13 study (2007 to 2009) in Perú. Pneumococcus was isolated and identified at study laboratory. Antibiotic sensitivity was determined by disc diffusion. Strains were serotyped by Sequential-multiplex-PCR.
Pneumococcal carriers decreases from 27%(573/2123) in pre-PCV13 to 21%(208/1000) in post-PCV13 (p<0.05). The antibiotic resistance increases (p<0.05) for cotrimoxazole(58% to 76%), Oxacillin(52% to 76% non-sensitive), azithromycin(29% to 50%), tetracycline(29% to 39%); and Clindamycin(13% to 29%) in post-PCV13. The most common pre-PCV13 serotype were: 19F(18.1%), 6B(14.3%); 23F(8.9%) and 14(6.5%) and the most common post-PCV13 serotype were: 15B/15C(13.9%), 6A/6B/6C/6D(11.5%) and 19A(5.3%). A positive association (p<0.001) between respiratory symptoms and pneumococcus was observed.
The decrease in pneumococcal nasopharyngeal carrier could be due to use of PCV13 vaccine. The antibiotic resistance is increasing compared to pre-PCV13. 15B/15C represents an emerging non-PCV13 vaccine serotype in our population.