Prevalence of PspA families and pilus islets among Streptococcus pneumoniae colonizing children before and after universal use of pneumococcal conjugate vaccines in Brazil

Abstract

In 2010, the 10-valent (PCV10) and 13-valent (PCV13) pneumococcal conjugate vaccines were introduced in Brazil to immunize children, resulting in serotype replacement. We analyzed 253 carriage isolates recovered from children aged <6 years in Brazil, including 124 and 129 isolates from the pre-PCV10/13 (December 2009-July 2010) and post-PCV10/13 (September-December 2014) periods, respectively, to investigate the prevalence of PspA families and pilus islets, potential vaccine candidates. Serotypes and resistance profiles were previously characterized. We used PCR to type PspA families (Fam1-3) and pilus islets (PI-1 and PI-2). We identified the PspA family of 130 (51.4%) isolates. PspA families 1, 2, and 3 were identified in 12.2%, 38.7%, and 0.4% of the isolates, respectively. Eighteen (58.1%) Fam1 isolates were serogroup 6. Nine (81.8%) of 11 serotype 14 isolates were Fam2. Fam1 isolates resistant to penicillin (50%), erythromycin (43.7%), clindamycin (31.2%), and chloramphenicol (6.2%) were only found after PCV10/13 introduction. Resistance among Fam2 isolates was higher in the post-PCV10/13 period to erythromycin (1.8% vs. 18.6%), clindamycin (0 vs. 13.9%), and tetracycline (10.9% vs. 16.3%). PI-I was detected in 42 (16.6%) isolates. Fourteen (56%) of 25 serotype 15B/C and nine (81.8%) of 11 serotype 14 isolates had PI-1 (p < 0.01). Eight (3.2%) isolates had PI-2, and six (75%) were serogroup 19. Five (2%) serogroup 19 isolates had both PI-1 and PI-2. We found associations between serogroups/serotypes, PspA families, and pilus islets, but distribution of PspA families and pilus islets was similar in both periods. After universal vaccination, we observed higher antimicrobial resistance frequencies, regardless PspA or pilus types.

Post-Vaccination Streptococcus pneumoniae Carriage and Virulence Gene Distribution among Children Less Than Five Years of Age, Cape Coast, Ghana

“…Because the majority of the piliated serotypes from this study were covered by PCV13, we expect that continuous use of the vaccine can eradicate these piliated VT from the population. The generally low prevalence of the pilus islets found in this study is in agreement with others [ 51 , 72 ]. Furthermore, the emergence of piliation in NVTs as seen in other studies [ 72 , 73 ] could be of concern to Ghana as they could expand and emerge in pneumococcal disease.…”

“…The generally low prevalence of the pilus islets found in this study is in agreement with others [ 51 , 72 ]. Furthermore, the emergence of piliation in NVTs as seen in other studies [ 72 , 73 ] could be of concern to Ghana as they could expand and emerge in pneumococcal disease. Additionally, the pilus islets were significantly associated with MDR and PCV13 serotypes ( p < 0.001) which is in agreement with previous studies [ 71 , 74 ].…”

Virulence-Associated Characteristics of Serotype 14 and Serogroup 9 Streptococcus pneumoniae Clones Circulating in Brazil: Association of Penicillin Non-susceptibility With Transparent Colony Phenotype Variants

“…All 315 isolates harbored psp A genes, demonstrating the wide occurrence of these genes among pneumococcal isolates as previously suggested ( McDaniel et al, 1998 ; Croney et al, 2012 ; Blumental et al, 2015 ; Kawaguchiya et al, 2018 ; Knupp-Pereira et al, 2019 ). A total of 30.8% (97 isolates) harbored psp A1 genes, while 69.2% (218 isolates) had psp A2 genes.…”

An in vivo atlas of host–pathogen transcriptomes during Streptococcus pneumoniae colonization and disease

“…However, zmpB has also been shown to be present in closely related commensal streptococcal species colonizing the human host, thereby possibly limiting its vaccine potential ( 39 ). PspA is also present in most pneumococcal strains, albeit exhibiting different alleles ( 40 ), and this protein has also been demonstrated to be protective against pneumococcal disease ( 41 ). Given that these are core proteins, surface-exposed, protective, and now found to be broadly highly expressed by the pneumococcus in vivo, this makes them potentially powerful candidates for the development of a serotype-independent pneumococcal vaccine.…”