Streptococcus agalactiae in neonatology: detection strategies

Background. Group B streptococcus (Streptococcus agalactiae, SGV) remains the main cause of neonatal sepsis and meningitis, despite a marked decrease due to the use of intranatal antibiotic prophylaxis. At the same time, delays in the detection and treatment of neonatal infections can cause serious consequences and, in some cases, the death of a newborn, on the other hand, unnecessary use of antibiotics also has harmful consequences (changes in the normal microbiota of a newborn, the development of antimicrobial resistance, etc.). At the same time, laboratories are constantly faced with the task of improving diagnostic approaches for the rapid and correct identification of newborns with infection.

The purpose of the study. To analyze the effectiveness, efficiency and timing of the results of bacteriological examination in neonatal sepsis and meningitis caused by Streptococcus agalactiae to determine the best diagnostic strategy.

Material and methods. In the period from January to November 2024, the case histories of 10 newborns with positive hemoculture for Streptococcus agalactiae were analyzed. Blood samples were taken under aseptic conditions according to the standard protocol. The identification of microorganisms was carried out by 2 methods: 1 — by standard subcultivation on nutrient cups and 2 — directly from positive vials using MALDI-TOF MS technology on a Vitek MS analyzer (BioMerieux, France) using the in-house method.

Results. The average time from the moment of sampling to placement in the hemocultivation device (A) was 13.1±7.4 hours, the average growth time of the microorganism, i.e., to a positive signal (B) was 6.7± 3.0, the average time for identification of the pathogen from a blood vial (C) was 20.2±13.1, the average sample turnover time in the laboratory (from the collection of the material to the issuance of the identification result to the clinician — D) was 42.0 ± 12.0 hours. When using the accelerated identification method directly from a positive vial, the average time C was 12.5 hours, D — 36.3 hours.

Conclusions. The use of an accelerated technique for the cultural detection of OHS in hemocultures of newborn children allowed to reduce the time of identification of the pathogen in a positive blood culture by 17.5 hours from 30 hours to 12.5 (more than 2 times), and the total time from obtaining the biomaterial to making a decision by the attending physician was reduced by 14 hours (from 50 hours to 36), i.e. almost 1.5 times.

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