Capsular genotype distribution of Group B Streptococcus colonization among at-risk pregnant women in Sao Paulo, Brazil

ABSTRACT Background: Vaccines in development against Group B Streptococcus (GBS) should contain the most prevalent capsular genotypes screened in the target population. In low- and middle-income countries epidemiological data on GBS carriage among pregnant women, a prerequisite condition for GBS neonatal sepsis, is needed to inform vaccine strategies. Objective: To investigate the prevalence of different GBS capsular genotypes that colonizes at-risk pregnant women in a private maternity hospital in São Paulo, Brazil. Methods: GBS strains isolated in routine maternity procedures from at-risk pregnant women from 2014 to 2018 were confirmed by mass spectrometry (MALDI-TOF) with subsequent DNA extraction for identification of capsular genotype through polymerase chain reaction (PCR). Demographic and gestational data were analyzed. Results: A total of 820 Todd-Hewitt broths positive for GBS were selected for streptococcal growth. Recovery and confirmation of GBS by MALDI-TOF were possible in 352. Strains were processed for determination of capsular genotype by PCR. From the total of 352 GBS isolates, 125 strains (35.5%) were genotyped as Ia; 23 (6.5%) as Ib; 41 (11.6%) as II; 36 (10.2%) as III; 4 (1.1%) as IV; 120 (34.1%) as V and 1 strain (0.3%) as VIII. Two isolates (0.7%) were not genotyped by used methodology. No statistically significant correlation between gestational risk factors, demographic data and distribution of capsular genotypes were found. Conclusions: GBS capsular genotypes Ia, Ib, II, III, and V were the most prevalent isolates colonizing at risk pregnant women in the present study. The inclusion of capsular genotypes Ia and V in the composition of future vaccines would cover 69.6% of capsular genotypes in the studied population. No statistically significant differences were observed between capsular genotype and gestational and demographic data and risk factors.

A survey of the incidence of neonatal sepsis by group B Streptococcus during a decade in a Brazilian maternity hospital

Group B Streptococcus (GBS) is the main etiological agent of neonatal sepsis in developed countries, however there is no detailed information on its incidence in Brazil. We registered the incidence and lethality of GBS infection in a Brazilian private maternity hospital from April 1991 to March 2000. Maternal risk factors contributing to neonatal infections were also scored. The rate of infection was determined by checking for GBS in the blood and liquor of symptomatic neonates within 72 hours of birth. Sepsis and/or early onset meningitis were diagnosed in 43 neonates (32 cases in blood, 1in liquor and 10 in blood and liquor). The overall incidence was 0.39 per thousand neonates and remained quite constant throughout the period, ranging from 0.25-0.63. Septic shock occurred in 33 neonates within 1 to 36 hours of birth (mean 15 hours). Among those patients, 26 (60) died between the 5th and the 85th hour after birth. Maternal risk factors, according to CDC criteria, included: gestational age below 37 weeks in 26 cases (60), amniorrhexis equal or superior to 18 hours in 7 cases (16), and maternal temperature equal or superior to 38(o)C in 4 cases (9). None of the mothers had received prophylactic antibiotics during labor nor were urine, rectal or vaginal swabs screened for GBS. Although the incidence of GBS infection in the population in this study was lower than that found in developed countries, its rate of mortality was higher. The death rate could be reduced through recognition of the risk factors and prophylactic antibiotics during labor.