Survival and biofilm formation by Group B streptococci in simulated vaginal fluid at different pHs

Borges, Sandra; Silva, Joana; Teixeira, Paula

doi:10.1007/s10482-011-9666-y

Cited by 69 publications

(51 citation statements)

References 17 publications

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“…In a recent study, Ho et al (37) found that a low pH induced biofilm formation in nutrientlimited medium (M9YE) but not in THB. Borges et al (27), Kaur et al (28), and Yang et al (38) found that GBS produced a greater amount of biofilm at pH 6.5 than at pH 4.2, and Konto-Ghiorghi et al (29) reported that a uniform biofilm was produced only on LB and RPMI 1640 supplemented with 1% glucose and not on THB. Manetti et al (39) observed that in S. pyogenes, the presence of glucose resulted in autoacidification of the medium and consequently biofilm formation.…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies have demonstrated GBS biofilm formation in vitro (26)(27)(28)(29), although the data regarding the effects of pH and medium composition are controversial. In a recent study, Ho et al (37) found that a low pH induced biofilm formation in nutrientlimited medium (M9YE) but not in THB.…”

Section: Discussionmentioning

confidence: 99%

“…Organisms within biofilms can withstand nutrient deprivation, pH changes, oxygen radicals, disinfectants, and antibiotics better than planktonic organisms can (25). The majority of the species of the Streptococcus genus have been shown to form biofilm, while just a limited number of studies have demonstrated GBS biofilm formation in vitro (26)(27)(28)(29). The glucose concentration in the culture medium was shown to modulate biofilm formation by GBS, although conflicting data have been reported regarding the biofilm-forming capacities of isolates of different serotypes and the correlation between biofilm formation and pH (26,27,29).…”

mentioning

confidence: 99%

“…The majority of the species of the Streptococcus genus have been shown to form biofilm, while just a limited number of studies have demonstrated GBS biofilm formation in vitro (26)(27)(28)(29). The glucose concentration in the culture medium was shown to modulate biofilm formation by GBS, although conflicting data have been reported regarding the biofilm-forming capacities of isolates of different serotypes and the correlation between biofilm formation and pH (26,27,29). We hypothesized that these contradictory results could be due to the absence of in vitro protocols that allow clear discrimination between strong and weak biofilm formers and unambiguous establishment of the role of bacterial culture conditions.…”

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confidence: 99%

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Acidic pH Strongly Enhances In Vitro Biofilm Formation by a Subset of Hypervirulent ST-17 Streptococcus agalactiae Strains

D’Urzo

Martinelli

Pezzicoli

et al. 2014

Appl Environ Microbiol

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Streptococcus agalactiae, also known as group B Streptococcus (GBS), is a primary colonizer of the anogenital mucosa of up to 40% of healthy women and an important cause of invasive neonatal infections worldwide. Among the 10 known capsular serotypes, GBS type III accounts for 30 to 76% of the cases of neonatal meningitis. In recent years, the ability of GBS to form biofilm attracted attention for its possible role in fitness and virulence. Here, a new in vitro biofilm formation protocol was developed to guarantee more stringent conditions, to better discriminate between strong-, low-, and non-biofilm-forming strains, and to facilitate interpretation of data. This protocol was used to screen the biofilm-forming abilities of 366 GBS clinical isolates from pregnant women and from neonatal infections of different serotypes in relation to medium composition and pH. The results identified a subset of isolates of serotypes III and V that formed strong biofilms under acidic conditions. Importantly, the best biofilm formers belonged to serotype III hypervirulent clone ST-17. Moreover, the abilities of proteinase K to strongly inhibit biofilm formation and to disaggregate mature biofilms suggested that proteins play an essential role in promoting GBS biofilm initiation and contribute to biofilm structural stability. Streptococcus agalactiae, also known as group B Streptococcus (GBS), is a leading cause of invasive neonatal infections worldwide. It is a common colonizer of the gastrointestinal and urogenital tracts of up to 40% of healthy individuals (1). However, under certain circumstances, GBS can become a life-threatening pathogen causing invasive infections in human neonates (2, 3). Earlyonset group B streptococcal disease occurs in infants less than 7 days old, and late-onset disease (LOD) occurs in infants between 7 and 89 days old. GBS is usually transmitted from mothers to newborns during childbirth (4), but it can also penetrate the human placenta (5), and in the case of LOD, it can be nosocomially acquired.Historically, GBS isolates have been classified into 10 different serotypes according to their capsular polysaccharide composition (6, 7). Multiple surveillance studies have indicated that all serotypes are able to colonize the vagina and perianal region of pregnant women, but five serotypes (Ia, Ib, II, III, and V) are predominant and are also the most frequent in human infections (8-12). In particular, serotype III accounts for 30 to 76% of neonatal disease cases (13,14). The use of multilocus sequence typing (MLST) allowed the classification of GBS isolates independently from their capsular serotypes and the identification of the bacterial genogroups more often associated with invasive infections in newborns (15). Serotype III isolates of a particular genotype cluster, sequence type 17 (ST-17), disproportionately cause late-onset GBS disease (15-19) and more frequently cause meningitis than other STs do (20). The precise mechanism by which ST-17 causes LOD more frequently than other STs do is not well unde...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Acidic pH Strongly Enhances In Vitro Biofilm Formation by a Subset of Hypervirulent ST-17 Streptococcus agalactiae Strains

D’Urzo

Martinelli

Pezzicoli

et al. 2014

Appl Environ Microbiol

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“…For instance, the GBS CovR/S system responds to pH wherein increased CovR/S regulation was observed under low (acidic) pH [65, 71–73]. Changes in pH also influences GBS adhesion [72, 74], survival [75], and biofilm formation [76, 77]. Of note, high vaginal pH and a non-lactobacilli dominated vaginal microbiome [78] are associated with women of African descent with higher incidence of GBS vaginal colonization [15, 21, 22] and neonatal disease [23–25].…”

Section: Bacterial Factors That Promote Gbs Vaginal Colonization Ascmentioning

confidence: 99%

Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies

Vornhagen

Waldorf

Rajagopal

2017

Trends in Microbiology

128

112

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Summary Group B Streptococcus (GBS) or Streptococcus agalactiae are β-hemolytic, Gram-positive bacteria that are a leading cause of neonatal infections. GBS commonly colonize the lower gastrointestinal and genital tracts and during pregnancy, neonates are at risk for infection. Although intrapartum antibiotic prophylaxis during labor and delivery has decreased the incidence of early onset neonatal infection, these measures do not prevent ascending infection that can occur earlier in pregnancy leading to preterm births, stillbirths, or late onset neonatal infections. Prevention of GBS infection in pregnancy is complex and likely influenced by multiple factors including pathogenicity, host factors, vaginal microbiome, false negative screening, and/or changes in antibiotic resistance. A deeper understanding of mechanisms of GBS infections during pregnancy will facilitate the development of novel therapeutics and vaccines. Here, we summarize and discuss important advancements in our understanding of GBS vaginal colonization, ascending infection and preterm birth.

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Vaginal prevention of Candida albicans: synergistic effect of lactobacilli and mannan oligosaccharides (MOS)

Faustino,

Pereira,

Pereira

et al. 2024

Appl Microbiol Biotechnol

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Vulvovaginal candidiasis (VVC) affects approximately 30–50% of women at least once during their lifetime, causing uncomfortable symptoms and limitations in their daily quality of life. Antifungal therapy is not very effective, does not prevent recurrencies and usually causes side effects. Therefore, alternative therapies are urgently needed. The goal of this work was to investigate the potential benefits of using mannan oligosaccharides (MOS) extracts together with a Lactobacillus sp. pool, composed by the most significant species present in the vaginal environment, to prevent infections by Candida albicans. Microbial growth of isolated strains of the main vaginal lactobacilli and Candida strains was assessed in the presence of MOS, to screen their impact upon growth. A pool of the lactobacilli was then tested against C. albicans in competition and prophylaxis studies; bacterial and yeast cell numbers were quantified in specific time points, and the above-mentioned studies were assessed in simulated vaginal fluid (SVF). Finally, adhesion to vaginal epithelial cells (HeLa) was also evaluated, once again resorting to simultaneous exposure (competition) or prophylaxis assays, aiming to measure the effect of MOS presence in pathogen adherence. Results demonstrated that MOS extracts have potential to prevent vaginal candidiasis in synergy with vaginal lactobacilli, with improved results than those obtained when using lactobacilli alone. Key points Potential benefits of MOS extracts with vaginal lactobacilli to prevent C. albicans infections. MOS impacts on growth of vaginal lactobacilli pool and C. albicans in SVF. MOS extracts in synergy with L. crispatus inhibit C. albicans adhesion in HeLa cells. Graphical Abstract

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Survival and biofilm formation by Group B streptococci in simulated vaginal fluid at different pHs

Cited by 69 publications

References 17 publications

Acidic pH Strongly Enhances In Vitro Biofilm Formation by a Subset of Hypervirulent ST-17 Streptococcus agalactiae Strains

Acidic pH Strongly Enhances In Vitro Biofilm Formation by a Subset of Hypervirulent ST-17 Streptococcus agalactiae Strains

Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies

Vaginal prevention of Candida albicans: synergistic effect of lactobacilli and mannan oligosaccharides (MOS)

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