Hydrogel Containing Oleoresin From Copaifera officinalis Presents Antibacterial Activity Against Streptococcus agalactiae.

Ana Elisa Belotto Morguette,Audrey Alesandra Stinghen Garcia Lonni,Nilton Syogo Arakawa,Patrícia Moraes Lopes Pereira,José Carlos Tomaz,Laís Fernanda De Almeida Spoladori,Sueli Fumie Yamada-Ogatta,Gilselena Kerbauy,Eliandro Reis Tavares,Cesar Armando Contreras Lancheros,Lucy Megumi Yamauchi,Gabriella Maria Andriani,Celso Vataru Nakamura,Briani Gisele Bigotto,Renata De Lima Varella,Fabio Goulart De Andrade,Marcos Luciano Bruschi

doi:10.3389/fmicb.2019.02806

Ana Elisa Belotto Morguette, Audrey Alesandra Stinghen Garcia Lonni + Show 15 more

Open Access

https://doi.org/10.3389/fmicb.2019.02806

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Abstract

Streptococcus agalactiae or Group B Streptococcus (GBS) remains a leading cause of neonatal infections worldwide; and the maternal vaginal-rectal colonization increases the risk of vertical transmission of GBS to neonates and development of infections. This study reports the in vitro antibacterial effect of the oleoresin from Copaifera officinalis Jacq. L. in natura (copaiba oil) and loaded into carbomer-hydrogel against planktonic and sessile cells of GBS. First, the naturally extracted copaiba oil was tested for the ability to inhibit the growth and metabolic activity of planktonic and sessile GBS cells. The time-kill kinetics showed that copaiba oil exhibited a dose-dependent bactericidal activity against planktonic GBS strains, including those resistant to erythromycin and/or clindamycin [minimal bactericidal concentration (MBC) ranged from 0.06 mg/mL to 0.12 mg/mL]. Copaiba oil did not inhibit the growth of different Lactobacillus species, the indigenous members of the human microbiota. The mass spectral analyses of copaiba oil showed the presence of diterpenes, and the kaurenoic acid appears to be one of the active components of oleoresin from C. officinalis related to antibacterial activity against GBS. Microscopy analyses of planktonic GBS cells treated with copaiba oil revealed morphological and ultrastructural alterations, displaying disruption of the cell wall, damaged cell membrane, decreased electron density of the cytoplasm, presence of intracellular condensed material, and asymmetric septa. Copaiba oil also exhibited antibacterial activity against established biofilms of GBS strains, inhibiting the viability of sessile cells. Low-cost and eco-friendly carbomer-based hydrogels containing copaiba oil (0.5% – CARB-CO 0.5; 1.0% – CARB-CO 1.0) were then developed. However, only CARB-CO 1.0 preserved the antibacterial activity of copaiba oil against GBS strains. This formulation was homogeneous, soft, exhibited a viscoelastic behavior, and showed good biocompatibility with murine vaginal mucosa. Moreover, CARB-CO 1.0 showed a slow and sustained release of the copaiba oil, killing the planktonic and sessile (established biofilm) cells and inhibiting the biofilm formation of GBS on pre-coated abiotic surface. These results indicate that carbomer-based hydrogels may be useful as topical systems for delivery of copaiba oil directly into de vaginal mucosa and controlling S. agalactiae colonization and infection.

Highlights

Streptococcus agalactiae or Group B Streptococcus (GBS) remains an important causative agent of potentially fatal neonatal infections (Evangelista and Freitas, 2015; Schrag et al, 2016; Seale et al, 2017; Shabayek and Spellerberg, 2018; Patras and Nizet, 2018)
A total of 9 group B Streptococcus strains isolated from vaginal-rectal swabs of women with no clinical evidence of infection were obtained from the bacterial collection of the Laboratório de Biologia Molecular de Microrganismos of the Universidade Estadual de Londrina (UEL), Londrina, Paraná, Brazil
We evaluated the effect of C. officinalis oil on the growth of L. acidophilus, L. casei, L. rhamnosus, L. crispatus, and L. gasseri, commensal members of the human vaginal microbiota (Hickey et al, 2012)

Summary

Introduction

Streptococcus agalactiae or Group B Streptococcus (GBS) remains an important causative agent of potentially fatal neonatal infections (Evangelista and Freitas, 2015; Schrag et al, 2016; Seale et al, 2017; Shabayek and Spellerberg, 2018; Patras and Nizet, 2018). The prevention strategy for early GBS neonatal infections is based on maternal bacterial screening during the 35–37th weeks of gestation and intravenous intrapartum antimicrobial prophylaxis (IAP) for GBS-colonized pregnant women. IAP has led to a dramatic reduction in the incidence of early GBS neonatal disease in developed countries (Russell et al, 2017; Toyofuku et al, 2017). These preventive measures, have not yet been fully adopted in most low- and middle-income countries (Le Doare et al, 2017). There is a need for affordable and safe alternatives for IAP

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