Congresso Brasileiro de Microbiologia 2023

Congresso Brasileiro de Microbiologia 2023

Resumo: 728-1

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MOLECULAR EPIDEMIOLOGY OF GROUP B STREPTOCOCCUS FROM CARRIAGE AND INFECTION IN BRAZIL TO IDENTIFY CANDIDATE VACCINE TARGETS, SEQUENCE TYPES, AND ANTIMICROBIAL RESISTANCE GENES

Autores:

Laura Maria Andrade de Oliveira (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO) ; Natália Silva Costa (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO) ; Leandro Correa Simões (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO) ; Penélope Saldanha Marinho (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO) ; Sérgio Eduardo Longo Fracalanzza (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO) ; Lucia Martins Teixeira (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO) ; Tatiana Castro Abreu Pinto (UFRJ - UNIVERSIDADE FEDERAL DO RIO DE JANEIRO)

Resumo:

Group B Streptococcus (GBS) is highlighted as a major agent of neonatal disease, accounting for 91,000 infant deaths each year, and it is also an important source of maternal infections. In this scenario, a maternal vaccine is considered the ideal preventive measure to reduce GBS disease burden. The most promising vaccine candidates at clinical trials include a trivalent (Ia, Ib, III) and a hexavalent (Ia, Ib, II, III, IV, V) polysaccharide-protein conjugate schemes and a protein subunit approach targeting the N-terminal domains of Alpha-like proteins. We evaluated GBS isolates from carriage (n=339) and cases of infections (n=36) in Brazil over a period of 44 years (1978-2021). Short-read whole genome sequencing was performed to predict sequence type (ST), serotype, antimicrobial resistance (AMR) genes, and surface protein genes. Carriage GBS (cGBS) belonged mostly to serotype Ia (46.6%), followed by serotypes II (18.6%), V (17.7%), III (8.8%), Ib (6.8%), and IX (1.8%). Seven clonal complexes (CCs) accounted for 96.2% of cGBS isolates, as follows: 23 (41%), 19 (16.5%), 1 (13%), 24 (11.8%), 103 (4.7%), 10 (4.7%), 17 (4.4%). A total of 79.4% of cGBS harbored tet genes (tetM=79.4%, tetO=2.9%, tetL=0.3%). Macrolide resistance genes were found in 27 (8%) isolates (ermA+ermB=2.4%; mefA+mrsD=5.6%). Nearly all cGBS (98.2%) harbored alpha protein family genes (rib=49.9%, alp1=11.8%, alp2/3=9.7%, alpha=26.8%); pili genes were found in 97.1% cGBS (PI-1=37.8%, PI-2a1=60.8%, PI-2a2=21.8%, PI-2b=10%), and serine-rich repeat glycoprotein determinants were harbored by 95.3% (srr1=90.9%, srr2=4.4%) isolates. Regarding GBS isolates from disease (dGBS), 36.1% belonged to serotype III, followed by serotypes Ia (25%), II (19.4%), V, (8.3%), IX (5.6%), Ib (5.6%). Most dGBS belonged to CC1 (30.6%), CC23 (27.8%), and CC17 (22.2%), although CC19 (11.1%) and CC130 (5.6%) were also found. A total of 80.6% of dGBS carried tet genes (tetM=63.9%, tetO=16.7%, tetL=2.8%), but macrolide resistance genes were not identified. As seen among cGBS, nearly all (97.2%) dGBS carried alpha protein family genes (rib=55.6%, alp1=22.2%, alpha=11%, alp2/3=8.3%), pili genes (PI-1=61%, PI-2a1=39%, PI-2a2=33%, PI-2b=22%), and serine-rich repeat glycoprotein determinants (srr1=75%, srr2=22%). Our study contributes with unprecedented whole genome sequence-based data of a comprehensive GBS collection in Brazil, shedding light on the molecular epidemiology, AMR and virulence profiles of human GBS from a low-and-middle income country perspective and inform vaccine design.

Palavras-chave:

Group B Streptococcus , Streptococcus agalactiae, antimicrobial resistance, molecular epidemiology, vaccine

Agência de fomento:

Instituto Nacional de Pesquisa em Resistência Antimicrobiana (INPRA); Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)