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Congresso Brasileiro de Microbiologia 2023
 		Resumo: 1070-1

1070-1

Antimicrobial Susceptibility and Genotypic Characterization of Invasive Streptococcus agalactiae Isolates from Brazil

Autores:
Julia Cristina Paiva Bruno (UFRJ - Federal University of Rio de Janeiro) ; Thomas Salles Dias (UFRJ - Federal University of Rio de Janeiro) ; Laura Maria Andrade de Oliveira (UFRJ - Federal University of Rio de Janeiro) ; Natalia Silva Costa (UFRJ - Federal University of Rio de Janeiro) ; Tatiana de Castro Abreu Pinto (UFRJ - Federal University of Rio de Janeiro)

Resumo:
Streptococcus agalactiae, also known as Group B Streptococcus, is a gram-positive coccus found in gastrointestinal and genitourinary microbiota. Although it was first described as infecting the udders of cattle causing mastitis, GBS is a leading cause of invasive neonatal infections and has emerged as an important cause of invasive infection in adults, especially the elderly. For this purpose, the present study aims to characterize GBS strains recovered from invasive disease in both adults and newborns from Brazil. A total of 12 strains isolated from adults and children between 1996 and 2020 in Brazil were included in the present study. Strains were identified by phenotypical tests and MALDI-TOF MS. Antimicrobial susceptibility profiles were assessed by disk diffusion test. Whole genome short-read sequencing was employed to characterize capsular types, antimicrobial resistance genes, and sequence types. Among the 12 strains, 6 (50.0%) were isolated from blood culture, three (25.0%) from cerebrospinal fluid, and one each (8.3%) from ascitic fluid, bone lesions, and bronchoalveolar lavage. Seven strains (58.3%) were identified as serotype III, while the second most prevalent was Ia (n=2, 16.7%), and Ib (n=2, 16.7%) followed by one strain belonging to serotype V (8.3%). Isolates were susceptible to all antimicrobial agents tested (penicillin, clindamycin, erythromycin, vancomycin, and levofloxacin) except for tetracycline, to which 8 isolates (66.7 %) showed phenotypic resistance. All strains were positive for CAMP production. Moreover, four STs were identified, namely ST-1 (2 strains), ST-17 (6 strains), ST-23 (3 strains), and ST-1925 (1 strain). tetM gene was found in 75.0% of the strains, while mreA was found in 50.0%. Our results showed that invasive GBS were susceptible to clinically relevant antimicrobials; however, resistance to tetracycline was detected. Additionally, it was observed that most strains, regardless of clinical source, belonged to serotype III and ST-17.

Palavras-chave:
 Group B Streptococcus, Streptococcus agalactiae, invasive disease, Whole Genome Sequencing


Agência de fomento:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científiczazo e Tecnológico CNPq.