Association of clustered regularly interspaced short palindromic repeats with genotyping and drug-resistance genes of group B Streptococcus / 中华围产医学杂志

ABSTRACT

Objective:To investigate the distribution of clustered regularly interspaced short palindromic repeats (CRISPR) in group B Streptococcus (GBS) in the genital tract of women during the third trimester and in infants with invasive infection and its relationship with multilocus sequence typing (MLST) and drug-resistance genes. Methods:This study retrospectively collected 84 GBS strains isolated from pregnant women with GBS colonization and infants with invasive GBS infection who were admitted to Children's Hospital Affiliated to Shanxi Medical University from January 2017 to January 2022. CRISPR, MLST, and drug-resistance phenotype and genes were detected and analyzed using χ 2 test or Fisher exact probability method. MEGA11 was used to construct a dendrogram. Results:There were ten sequence typing in the 84 GBS strains and ST10 was the dominant one (46.4%). GBS was sensitive to penicillin, and its resistance rates to erythromycin (75.0%) and clindamycin (73.8%) were high. Among the 17 invasive GBS strains, ST10 had 100% resistance to erythromycin, clindamycin, and levofloxacin. CRISPR1 gene was amplified in 62 strains (73.8%). CRISPR1-positive strains had a significantly higher proportion of ST10 [56.5%(35/62) vs 18.2%(4/22), χ 2=9.56, P=0.002] and ermB, gyrA, parC [54.8%(34/62) vs 22.7%(5/22), 67.7%(42/62) vs 36.4%(8/22), 71.0%(44/62) vs 36.4%(8/22); χ 2=6.73, 6.64, and 8.25, all P<0.05], and a lower proportion of ermA [6.5%(4/62) vs 31.8%(7/22), χ 2=7.09, P=0.008] than CRISPR1-negative strains. Conclusions:ST10 is the main GBS genotype among the colonized microbiota the genital tract of pregnant women and in infants with invasive GBS infection, which is also a dominant type in CRISPR1-positive strains. GBS is sensitive to penicillin and CRISPR1 gene is linked to the spread of some drug-resistance genes.