Avaliação de aspectos clínico-epidemiológicos e de patogenicidade de Streptococcus agalactiae isolados de gestantes e neonatos

Abstract

Streptococcus agalactiae (group B streptococci, GBS) is an opportunistic microorganism that makes up the normal amphibian microbiota of the human gastrointestinal, oral, and rectal/vaginal tracts. S. agalactiae can ascend to the uterus in colonized pregnant women, cross the placental barrier and cause complications that can even lead to neonatal death. Monitoring the mother and child at the hospital/maternity of origin is extremely important. Therefore, this study had as its main objective the evaluation of clinical-epidemiological aspects and pathogenicity of S. agalactiae isolated from pregnant women and newborns treated at Maternidade Carmela Dutra (Rio de Janeiro, RJ). From January 2018 to February 2020, 305 clinical specimens were collected, of which 225 (73,7%) were clinical specimens (vaginal, rectal, urine and secretion) from pregnant women between the 34th-37th week of pregnancy and 80 (26,2%) clinical specimens (umbilicus and external ear) of neonates born from 24 to 48 hours after birth, which were submitted to identification by serology and by the MALD TOF technique. The 29 (9,5%) samples isolated from pregnant women and 19 (6,2%) samples from neonates were identified as belonging to the S. agalactiae species, respectively. The multiplex PCR results showed that the capsular type Ia was predominant in pregnant women with 55% (n=16), followed by type V with 20.6% (n=6), type II with 10.3% (n=3) and III with 14% (n=4). In neonatal samples, there was a prevalence of capsular type V (n=9; 47%), followed by types Ia (n=4; 21%), III (n=2; 11%), II (n=2; 11% ), VI (n=1; 5%) and VII (n=1; 5%). Among the comorbidities most frequently observed in the pregnant women studied, gestational hypertension (24%), gestational diabetes mellitus (17%) and urinary infections (17%) were the ones that presented the highest rate of complications during childbirth. In addition, the capsular type Ia was identified in samples from pregnant women with urinary tract infection and gestational diabetes mellitus, characteristics of high-risk pregnancies. Capsular types Ia and V had a higher prevalence of comorbidities when compared to the other capsular types. Pregnant women aged 29-36, followed by 21-28 years old were prevalent with 28% and 17% of bacterial samples, respectively. Brown (24%) and white (17%) mothers were predominant compared to black mothers (14%). We can also observe a greater number of colonization by S. agalactiae in isolates from the umbilicus of newborns. These results demonstrate the importance of analyzing pregnant women colonized by S. agalactiae, including neonates of colonized mothers who may develop invasive infections through umbilical and external ear colonization during normal delivery