Molecular characterization of prevalence, serotypes, virulence factors, and antibiotic resistance of Streptococcus agalactiae in a maternity hospital, Iran

Abstract

Objective: To characterize group B streptococcus (GBS) isolated from patients at the Kosar Maternity Hospital in Ghazvin, a labor-dominated industrial city of Iran for their serotypes, virulence factors, and antibiotic resistance. Materials and Methods:A total of 270 samples were collected from vaginal swabs, midstream urine, and rectal swabs of 90 adult participants throughout 2019-2021 during 35-37 weeks of gestation. Standard bacteriological methods, CAMP test, and amplification of the CFB gene encoding CAMP factor by polymerase chain reaction using specific primers were carried out to identify the GBS isolates. The overall prevalence and identification of GBS serotypes and virulence factors were studied using multiplex PCR. The isolates were subjected to antimicrobial susceptibility tests. Results:The preliminary identification tests revealed a 17.6% prevalence of GBS among the patients. The multiplex PCR led to the identification of the serotypes Ia (25%), Ib (50%), and II (25%). Three distinct virulence gene profiles of cylE, lmb, and bca were identified. The serotype (Ia) with three virulence factors of CylE, lmb, bca isolated from rectal samples was resistant to all antibiotics except vancomycin. The serotype Ib isolated from urine samples was resistant to all antibiotics except Ampicillin, while serotype II was sensitive to all the antibiotics except cefotaxime. Conclusions:The prevalence of colonization and antibiotic resistance of GBS is relatively high in mothers who participated in the present study. Resistance to commonly administered antibiotics indicates that other measures such as vaccination are potentially useful to prevent and control GBS in this population. Pregnant mothers should be screened for GBS colonization and antimicrobial susceptibility testing. This study has provided initial data on the genotypes and prevalence of virulence genes and antibiogram profile in GBS isolates obtained at the

Editorial comments to the articles published in Volume 8

“…Group B Streptococcus (GBS) has been the main cause of bacterial infection in newborns, while its colonization in the genitourinary and gastrointestinal tracts is generally asymptomatic in pregnant women. Aboutorabi et al [2] characterized GBS isolated from vaginal swabs, midstream urines, and rectal swabs in 90 participants at 35-37 weeks of gestation at a single institution in Iran. Overall, GBS was detected in 17.6% of the patients.…”