Serotypes and antibiotic susceptibility of Streptococcus agalactiae strains isolated from invasive neonatal infections

Abstract

The purpose of the study: to determine the serotypes and antibiotic susceptibility of strains of streptococcus agalactiae isolated from invasive neonatal infections. Material and methods: Fifty-five strains of Streptococcus agalactiae were selected isolated from invasive cerebrospinal fluid (CSF) and blood infections. The strains were confirmed by the Api 20Strep galleries and tested against the following antibiotics: penicillin G, ampicillin, erythromycin, clindamycin, tetracycline, ofloacin, levofloacin, gentamycin 500 μg, quinpristin-dalfopristin, chloramphenicol, vancomycin, interpretation was carried out according to the recommendations of the CLSI 2020 and kanamycin 1000 μg was interpreted according to the Ca-SFM standards. The serotyping of the strains was carried out according to the protocol of Monica Impéri Results: All strains were sensitive to penicillin G and ampicillin as well as vancomycin and fluoroquinolone; 92.7% are resistant to tetracyclines, 34.5% to erythromycin, 32.7% to clindamycin, 27.3% to chloramphenicol and 25.5% to kanamycin. The distribution of serotypes was as follows: serotype III is the majority with 56.4% followed by serotype Ia with 21.8% then serotype V with 14.5%. Conclusion: The strains of Streptococcus agalactiae remain sensitive to betalactamines, resistance to macrolides was around 35%, whereas that of aminoglycosides was 25%.Serotype III is the main serotype in invasive strains