| Congresso Brasileiro de Microbiologia 2023 | Resumo: 619-1 | ||||
Resumo:Streptococcus agalactiae (group B Streptococcus, GBS) is an asymptomatic colonizer of healthy adults' digestive and genitourinary tracts, the cause of neonatal diseases, and agent of infections in immunocompromised and elderly. Urinary tract infections caused by GBS in pregnant women are related to miscarriage, intrauterine fetal death, chorioamnionitis, and rupture of the amniotic membrane, causing premature births. The drugs of choice for humans GBS infection treatment or prophylaxis include penicillin and cephalosporins, clindamycin or macrolides, and vancomycin. The clinical use of tetracycline in humans is limited due to resistance. In addition to antimicrobial prophylaxis, implementing a vaccine based on the sialic acid-rich capsular polysaccharide (CPS) prevalent types for pregnant women is a promising strategy to prevent neonatal and infant GBS disease. GBS expresses ten types of CPS (Ia, Ib, II-IX), so the description of the prevalent serotypes in a region is crucial to vaccine development. We characterized 106 GBS isolated from different clinical specimens of outpatients in João Pessoa – PB. We determined the isolates' capsular types by multiplex PCR and their susceptibility to penicillin, erythromycin, vancomycin, clindamycin, levofloxacin, chloramphenicol, tetracycline, and linezolid by disc diffusion according to the CLSI; we used E-test to determine the minimal inhibitory concentration of penicillin. We analyzed the clonality of the isolates using DNA macrorestriction followed by pulsed-field gel electrophoresis (PFGE) and chose 11 to sequence the whole genome by Nanopore and Illumina technologies. Three isolates were non-typable by PFGE, neither using SmaI nor XmaI. There was a high GBS clone diversity among the outpatients in the Paraíba community; the 103 isolates clustered in 58 pulsotypes (H1-H59). Two isolates were CPS non-typeable. Seventy-seven out of 103 isolates were resistant to tetracycline, a feature of human-adapted GBS strains. In addition, nine isolates were resistant to clindamycin, three to chloramphenicol, twelve to erythromycin, and one to levofloxacin. One isolate was intermediate to chloramphenicol, nine to erythromycin, and six to tetracycline. All isolates were susceptible to penicillin and vancomycin. Eleven isolates were selected based on the PFGE and had their genomes sequenced. Two isolates belonged to Sequence Type (ST) 196, two to ST144, two to ST28, and two to ST651. The remaining isolates belonged to ST12, ST19, and ST23. All the sequenced isolates were positive for the macrolide resistance gene mreA. Most tetracycline-resistant isolates had the tetM gene (73%), but tetS and tetO were also found, according to Resfinder. After a BLASTn search, eight isolates (73%) presented a combination of the virulence genes bca, cfb, cspA, cylE, fbsA, hylB, rib, scpB, and sip. Two isolates (18%) did not present scpB, and only one isolate (9%) showed the virulence factor bac altogether with the others. In conclusion, we found a high diversity of virulent GBS strains in the community. mreA and tetM resistance genes were the most detected. Serotypes Ia and V showed the most increased occurrence among the isolates, and the Paraíba community patients still can count on the main antibiotic alternatives to treat GBS infections. Palavras-chave: GBS, capsular serotype, Streptococcus agalactiae, Virulence Agência de fomento:FAPESP 2019/23684-9; FAPESP 2022/14323-5, PIBIC, FAPESQ | |||||