| Congresso Brasileiro de Microbiologia 2023 | Resumo: 670-1 | ||||
Resumo:Group B Streptococcus (GBS) is a major agent of neonatal infections in humans and also poses a risk to animal health, notably cattle and fish. The GBS population is composed by several lineages that can differ in their epidemiology, virulence, antimicrobial resistance, and zoonotic potential. Serotype III is one of the most prevalent in the GBS population, being found not only in humans, but also in animal strains. The development of alternative cost-effective typing methods is desirable for GBS surveillance and disease control once traditional methods (e.g. WGS, MLST) are expensive and not easily accessible in low-and-middle income countries (LMIC). Here, we assessed the potential of CRISPR1-RFLP as a typing method to discriminate GBS isolates belonging to serotype III from human (carriage=70% and infectious disease=30%; n=20), cattle (bovine mastitis; n=20), and fish (farm/outbreak; n=20) hosts, recovered between 1987 and 2020 in Brazil. CRISPR1 elements were amplified by PCR and then subjected to RFLP (DdeI enzyme). The fingerprinting profiles were analyzed with BioNumerics v7.6.3. Multi-locus sequence typing (MLST) results were included for comparative purposes. CRISPR1-RFLP was able to distribute the 60 isolates into 12 clusters and 7 singletons assuming a cut-off point of 80% of similarity (Simpson’s Index of Diversity (SID) =0.903), showing a similar discriminatory potential with MLST (SID =0.827). The clustering was driven mainly by the origin of GBS strains (Adjusted Wallace (AW) coefficient =0.879). The clonal complexes (CC) defined by MLST dictated the distribution of strains from the same host in different clusters. Bovine isolates were distributed in four clusters and belonged mostly (75%) to CC91 and CC61 (AW =0.827). ST91 is a double locus variant of ST61, which is a host-specific GBS lineage well-adapted to cattle. Human GBS strains in turn were grouped in 5 clusters represented mostly (90%) by CC17 and CC23. ST17 represents a human hypervirulent GBS lineage and recognized as the main cause of GBS neonatal meningitis, while ST23 is associated with asymptomatic carriage. All piscine isolates belonged to ST283, except one, that curiously belonged to ST17. ST283 represents a hypervirulent lineage associated with foodborne outbreak of invasive disease in humans. Even though the piscine isolates belonged to only two STs, they were assigned to three clusters by CRISPR1-RFLP, according to the year and region of isolation. This indicate that CRISPR1-RFLP has a higher discriminatory potential for fish GBS, which are poorly discriminated by MLST. Our results indicate that CRISPR1-RFLP is an alternative and cost-effective technique for strain-typing of GBS lineages adapted to multiple hosts, being more accessible and with good potential to replace MLST. Hence, CRISPR-typing has the potential to be incorporated into routine epidemiological surveillance, including the screening of animal human strains. Interspecies transmission of host-generalist GBS lineages was already demonstrated, so surveillance of GBS strains circulating among different hosts should be performed in a routine basis in both veterinary and human medicine.
Development Agency: CAPES/Coordenação de Aperfeiçoamento de Pessoal de Ensino Superior Finance Code 001; CNPQ/ Conselho Nacional de Desenvolvimento Científico e Tecnológico; FAPERJ/ Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro. Palavras-chave: Streptococcus agalactiae, Group B Streptococcus, One Health, epidemiology, molecular typing Agência de fomento:CNPq/CAPES/FAPERJ | |||||