Cyclic variation in the adherence of group B streptococci to human vaginal epithelial cells

Zawaneh, Sam M.; Ayoub, Elía M.; Baer, Herman; Cruz, Amelia C.; Spellacy, William N.

doi:10.1016/0002-9378(81)90030-2

Cited by 21 publications

(16 citation statements)

References 35 publications

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“…Several proteins have already been reported to be important for ST-17 strain adhesion to solid surfaces or attachment to host cells or extracellular matrix (21,42,45,46). Our data suggest that the contradictory reports about the effects of pH on GBS adherence to epithelial cells (44,(47)(48)(49), like previous reports about the effects of pH on biofilm formation, could be due to the limited number of GBS strains tested and the methods used.…”

Section: Figmentioning

confidence: 56%

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: Figmentioning

confidence: 56%

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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“…In 1979, Botta et al found that the adherence of GBS strains (types Ia, Ib, II, and III) to human vaginal cells was greater at neutral pH than at acidic pH (3). In the same year, another study showed that the adherence of a type III GBS strain to human vaginal cells was maximal at pH 5.5 to 6.5 and declined significantly at pH values below and above this range (51). Both studies used vaginal cells directly collected from volunteers and performed adherence assays using suspensions of cells and bacteria.…”

Section: Discussionmentioning

confidence: 99%

CsrRS and Environmental pH Regulate Group B Streptococcus Adherence to Human Epithelial Cells and Extracellular Matrix

2012

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Streptococcus agalactiae (group B Streptococcus or GBS) is a common colonizer of the gastrointestinal and genital tracts and an important cause of invasive infections in newborn infants and in adults with predisposing chronic conditions or advanced age. Attachment to epithelial surfaces at mucosal sites is a critical step in the successful colonization of a human host, and regulation of this process is likely to play an important role in both commensalism and dissemination to cause invasive disease. We found that inactivation of the CsrRS (or CovRS) two-component system increased GBS adherence to epithelial cells derived from human vaginal, cervical, and respiratory epithelium, as well as increasing adherence to extracellular matrix proteins and increasing biofilm formation on polystyrene. Neutral (as opposed to acidic) pH enhanced GBS binding to vaginal epithelial cells and to fibrinogen and fibronectin, effects that were partially dependent on CsrRS. The regulatory effects of CsrRS and environmental pH on bacterial adherence correlated with their effects on the expression of multiple surface adhesins, as assessed by quantitative reverse transcription-PCR. We conclude that GBS adherence to epithelial and abiotic surfaces is regulated by the CsrRS twocomponent system and by environmental pH through their regulatory effects on the expression of bacterial surface adhesins. Dynamic regulation of GBS adherence enhances the organism's adaptability to survival in multiple niches in the human host.

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“…GBS attaches to and/or invades a variety of human tissues, including embryonic, fetal, and adult buccal epithelial cells (12,21), embryonic chorioamnion cells (6,22), vaginal epithelial cells (23), respiratory epithelial cells (8,16,18), umbilical vein endothelial cells (5), brain microvascular endothelial cells (13), and chorionic and amnionic epithelial cells (22). The environmental signals that regulate the invasiveness and pathogenic potential of GBS, however, are not well elucidated.…”

Section: Discussionmentioning

confidence: 99%

Oxygen Regulates Invasiveness and Virulence of Group B Streptococcus

et al. 2003

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The facultative anaerobe group B Streptococcus (GBS) is an opportunistic pathogen of pregnant women, newborns, and the elderly. Although several virulence factors have been identified, environmental factors that regulate the pathogenicity of GBS have not been well characterized. Using the dynamic in vitro attachment and invasion system (DIVAS), we examined the effect of oxygen on the ability of GBS to invade immortalized human epithelial cells. GBS type III strain M781 invaded human epithelial cells of primitive neurons, the cervix, the vagina, and the endometrium in 5-to 400-fold higher numbers when cultured at a cell mass doubling time (t d ) of 1.8 h than at a slower t d of 11 h. Invasion was optimal when GBS was cultured at a t d of 1.8 h in the presence of >5% oxygen and was significantly reduced without oxygen. Moreover, GBS grown in a chemostat under highly invasive conditions (t d of 1.8 h, with oxygen) was more virulent in neonatal mice than was GBS grown under suboptimal invasion conditions (t d of 1.8 h, without oxygen), suggesting a positive association between in vitro invasiveness with DIVAS and virulence.

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Cyclic variation in the adherence of group B streptococci to human vaginal epithelial cells

Cited by 21 publications

References 35 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

CsrRS and Environmental pH Regulate Group B Streptococcus Adherence to Human Epithelial Cells and Extracellular Matrix

Oxygen Regulates Invasiveness and Virulence of Group B Streptococcus

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