Acid Stress Response Mechanisms of Group B Streptococci

Abstract

Group B streptococcus (GBS) is a leading cause of neonatal mortality and morbidity in the United States and Europe. It is part of the vaginal microbiota in up to 30% of pregnant women and can be passed on to the newborn through perinatal transmission. GBS has the ability to survive in multiple different host niches. The pathophysiology of this bacterium reveals an outstanding ability to withstand varying pH fluctuations of the surrounding environments inside the human host. GBS host pathogen interations include colonization of the acidic vaginal mucosa, invasion of the neutral human blood or amniotic fluid, breaching of the blood brain barrier as well as survival within the acidic phagolysosomal compartment of macrophages. However, investigations on GBS responses to acid stress are limited. Technologies, such as whole genome sequencing, genome-wide transcription and proteome mapping facilitate large scale identification of genes and proteins. Mechanisms enabling GBS to cope with acid stress have mainly been studied through these techniques and are summarized in the current review

Pathobionts in the Vaginal Microbiota: Individual Participant Data Meta-Analysis of Three Sequencing Studies

“…This keeps BV-anaerobes at bay but perhaps not pathobionts. Streptococci, for example, can tolerate low vaginal pH very well (Shabayek and Spellerberg, 2017). Sexual risk-taking is an important proven risk factor for anaerobic dysbiosis (van de Wijgert et al, 2014), but associations with pathobionts detection and/or levels were inconsistent in this meta-analysis.…”

Comparative Genomics of Lactobacillus crispatus from the Gut and Vagina Reveals Genetic Diversity and Lifestyle Adaptation

“…Compared with the gut, the vagina has a lower pH (4 ± 0.5) [35]. Low pH helps reduce the risk of gynecological diseases and maintain female reproductive health [36].…”

“…The gene encoding manganese transport protein was presented only in vagina-sourced strains. This protein can take up Mn 2+ and expel protons out of the cell to take part in the acid response, maintaining intracellular pH homeostasis [35]. Meanwhile, Mn 2+ can also help in protecting bacteria against oxidative stress [37].…”

Microbial response to acid stress: mechanisms and applications

“…Such systems have been termed amino aciddependent acid tolerance systems. The arginine deaminase (ADI) system has been identified as an important defense mechanism in several bacteria against damage by acid (Liu et al 2015c;Shabayek and Spellerberg 2017). Three steps are involved in this system (Fig.…”