Group B-Streptococcus (GBS)

A special issue of Pathogens (ISSN 2076-0817). This special issue belongs to the section "Bacterial Pathogens".

Deadline for manuscript submissions: closed (20 November 2022) | Viewed by 34874

Special Issue Editors


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Guest Editor
1. St. George’s, University of London, London SW17 0RE, UK
2. MRC/UVRI@LSHTM Uganda Resaerch Unit, Entebbe PO Box 49, Uganda
Interests: maternal and neonatal immunization; clinical vaccine trials; neonatal immunity to vaccines; human challenge models
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Infection and Immunity Research Institute, St. George's University of London, London, UK
Interests: Bronchiolitis; rotavirus gastroenteritis; immune restoration inflammatory syndrome (IRIS)

Special Issue Information

Dear Colleagues,

Group B Streptococcus (Streptococcus agalactiae, GBS) is a major cause of neonatal and young infant sepsis worldwide. It also causes disease in pregnant women, the elderly, and those with underlying comorbidities.

Many aspects of GBS remain unexplored: these include whether early- and late-onset disease are the same condition, or whether late-onset disease occurs because of immune dysregulation in the intestine or in blood; whether breastmilk is a potential cause of infection, and whether and how breastmilk might protect against infection; what bacterial targets are preserved globally that might assist vaccine design; whether rapid diagnostics can be used in low-income settings to identify women at risk of transferring GBS to their infants; whether an amount of antibody transferred via the placenta can be determined above which an infant is protected from GBS disease and whether a vaccine would be effective in the elderly as well as in pregnant women.

The aims of this Special Issue are to better understand the host–pathogen interaction in order to advance the field of GBS.

Prof. Dr. Kirsty Le Doare
Dr. Konstantinos Karampatsas
Guest Editors

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Keywords

  • Group B Streptococcus Streptococcus agalactiae

Published Papers (15 papers)

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11 pages, 871 KiB  
Article
Geographical, Temporal and Host-Species Distribution of Potentially Human-Pathogenic Group B Streptococcus in Aquaculture Species in Southeast Asia
by Wanna Sirimanapong, Nguyễn Ngọc Phước, Chiara Crestani, Swaine Chen and Ruth N. Zadoks
Pathogens 2023, 12(4), 525; https://doi.org/10.3390/pathogens12040525 - 28 Mar 2023
Cited by 1 | Viewed by 1779
Abstract
Group B Streptococcus (GBS) is a major pathogen of humans and aquatic species. Fish have recently been recognized as the source of severe invasive foodborne GBS disease, caused by sequence type (ST) 283, in otherwise healthy adults in Southeast Asia. Thailand and Vietnam [...] Read more.
Group B Streptococcus (GBS) is a major pathogen of humans and aquatic species. Fish have recently been recognized as the source of severe invasive foodborne GBS disease, caused by sequence type (ST) 283, in otherwise healthy adults in Southeast Asia. Thailand and Vietnam are among the major aquaculture producers in Southeast Asia, with GBS disease reported in fish as well as frogs in both countries. Still, the distribution of potentially human-pathogenic GBS in aquaculture species is poorly known. Using 35 GBS isolates from aquatic species in Thailand collected from 2007 to 2019 and 43 isolates from tilapia collected in Vietnam in 2018 and 2019, we have demonstrated that the temporal, geographical, and host-species distribution of GBS ST283 is broader than previously known, whereas the distribution of ST7 and the poikilothermic lineage of GBS are geographically restricted. The gene encoding the human GBS virulence factor C5a peptidase, scpB, was detected in aquatic ST283 from Thailand but not in ST283 from Vietnam or in ST7 from either country, mirroring current reports of GBS strains associated with human sepsis. The observed distribution of strains and virulence genes is likely to reflect a combination of spill-over, host adaptation through the gain and loss of mobile genetic elements, and current biosecurity practices. The plastic nature of the GBS genome and its importance as a human, aquatic, and potentially foodborne pathogen suggests that active surveillance of GBS presence and its evolution in aquaculture systems may be justified. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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10 pages, 1036 KiB  
Article
Alterations in Genes rib, scpB and Pilus Island Decrease the Prevalence of Predominant Serotype V, Not III and VI, of Streptococcus agalactiae from 2008 to 2012
by I-An Tsai, Yaochi Su, Ying-Hsiang Wang and Chishih Chu
Pathogens 2022, 11(10), 1145; https://doi.org/10.3390/pathogens11101145 - 3 Oct 2022
Cited by 1 | Viewed by 1328
Abstract
Streptococcus agalactiae (GBS) can infect newborns, pregnant women and immunocompromised or elderly people. This study aimed to investigate differences in three pilus genes and virulence genes pavA, cfb, rib and scpB and changes in predominant serotypes III, V and VI from [...] Read more.
Streptococcus agalactiae (GBS) can infect newborns, pregnant women and immunocompromised or elderly people. This study aimed to investigate differences in three pilus genes and virulence genes pavA, cfb, rib and scpB and changes in predominant serotypes III, V and VI from 2008 to 2012. The susceptibilities to penicillin, ceftriaxone, azithromycin, erythromycin, clindamycin, levofloxacin and moxifloxacin of 145 GBS strains of serotype III, V and VI strains from 2008 and 2012 were determined using disc diffusion method. PCR identification of ST-17, the pilus genes and virulence genes; multilocus sequence typing (MLST); and conserved domain and phylogenetic analysis of scpB-1 and scpB-2 proteins were performed. A dramatic number reduction was observed in serotype V, not III and V, from 2008 to 2012. The rate of resistance to azithromycin, clindamycin and erythromycin was the highest in serotype V. ST-17 was only found in serotype III with pilus genes PI-1+PI-2b. The major pilus genotype was PI-1+PI-2a. Serotype V without the rib gene was reduced in number between two studied years. Compared to scpB-1, scpB-2 had a 128-bp deletion in a PA C5a-like peptidase domain and putative integrin-binding motif RGD. In conclusion, reduction in serotype V may be due to presence of scpB-2 or lack of genes scpB and rib. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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13 pages, 2345 KiB  
Article
Akt Inhibition Promotes Autophagy and Clearance of Group B Streptococcus from the Alveolar Epithelium
by Ioanna Pantazi, Iosif Papafragkos, Ourania Kolliniati, Ioanna Lapi, Christos Tsatsanis and Eleni Vergadi
Pathogens 2022, 11(10), 1134; https://doi.org/10.3390/pathogens11101134 - 30 Sep 2022
Cited by 2 | Viewed by 1821
Abstract
Group B Streptococcus (GBS) is a gram-positive bacterium that is harmless for healthy individuals but may provoke invasive disease in young infants and immunocompromised hosts. GBS invades the epithelial barriers to enter the bloodstream, and thus strategies that enhance epithelial cell responses may [...] Read more.
Group B Streptococcus (GBS) is a gram-positive bacterium that is harmless for healthy individuals but may provoke invasive disease in young infants and immunocompromised hosts. GBS invades the epithelial barriers to enter the bloodstream, and thus strategies that enhance epithelial cell responses may hamper GBS invasion. In the present study, we sought to investigate whether the inhibition of Akt, a kinase that regulates host inflammatory responses and autophagy via suppression of mTOR, can enhance the response of non-phagocytic alveolar epithelial cells against GBS. Treatment of the alveolar epithelial cell line A549 with the Akt inhibitor MK-2206 resulted in the enhanced production of reactive oxygen species and inflammatory mediators in response to GBS. Additionally, Akt inhibition via MK-2206 resulted in elevated LC3II/I ratios and increased autophagic flux in alveolar epithelial cells. Importantly, the inhibition of Akt promoted GBS clearance both in alveolar epithelial cells in vitro and in lung tissue in vivo in a murine model of GBS pneumonia. The induction of autophagy was essential for GBS clearance in MK-2206 treated cells, as knockdown of ATG5, a critical component of autophagy, abrogated the effect of Akt inhibition on GBS clearance. Our findings highlight the role of Akt kinase inhibition in promoting autophagy and GBS clearance in the alveolar epithelium. The inhibition of Akt may serve as a promising measure to strengthen epithelial barriers and prevent GBS invasion in susceptible hosts. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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21 pages, 2776 KiB  
Article
Nitric Oxide Production and Effects in Group B Streptococcus Chorioamnionitis
by Mary Frances Keith, Kathyayini Parlakoti Gopalakrishna, Venkata Hemanjani Bhavana, Gideon Hayden Hillebrand, Jordan Lynn Elder, Christina Joann Megli, Yoel Sadovsky and Thomas Alexander Hooven
Pathogens 2022, 11(10), 1115; https://doi.org/10.3390/pathogens11101115 - 28 Sep 2022
Cited by 2 | Viewed by 2381
Abstract
Intrauterine infection, or chorioamnionitis, due to group B Streptococcus (GBS) is a common cause of miscarriage and preterm birth. To cause chorioamnionitis, GBS must bypass maternal-fetal innate immune defenses including nitric oxide (NO), a microbicidal gas produced by nitric oxide synthases (NOS). This [...] Read more.
Intrauterine infection, or chorioamnionitis, due to group B Streptococcus (GBS) is a common cause of miscarriage and preterm birth. To cause chorioamnionitis, GBS must bypass maternal-fetal innate immune defenses including nitric oxide (NO), a microbicidal gas produced by nitric oxide synthases (NOS). This study examined placental NO production and its role in host-pathogen interactions in GBS chorioamnionitis. In a murine model of ascending GBS chorioamnionitis, placental NOS isoform expression quantified by RT-qPCR revealed a four-fold expression increase in inducible NOS, no significant change in expression of endothelial NOS, and decreased expression of neuronal NOS. These NOS expression results were recapitulated ex vivo in freshly collected human placental samples that were co-incubated with GBS. Immunohistochemistry of wild type C57BL/6 murine placentas with GBS chorioamnionitis demonstrated diffuse inducible NOS expression with high-expression foci in the junctional zone and areas of abscess. Pregnancy outcomes between wild type and inducible NOS-deficient mice did not differ significantly although wild type dams had a trend toward more frequent preterm delivery. We also identified possible molecular mechanisms that GBS uses to survive in a NO-rich environment. In vitro exposure of GBS to NO resulted in dose-dependent growth inhibition that varied by serovar. RNA-seq on two GBS strains with distinct NO resistance phenotypes revealed that both GBS strains shared several detoxification pathways that were differentially expressed during NO exposure. These results demonstrate that the placental immune response to GBS chorioamnionitis includes induced NO production and indicate that GBS activates conserved stress pathways in response to NO exposure. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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11 pages, 747 KiB  
Article
Changes in Group B Streptococcus Colonization among Pregnant Women before and after the Onset of the COVID-19 Pandemic in Brazil
by Natália Silva Costa, André Rio-Tinto, Isabella Bittencourt Ferreira Pinto, Danielle Cristina dos Santos Silva Alvim, Amanda de Assis Rocha, Laura Maria Andrade Oliveira, Ana Caroline Nunes Botelho, Sergio Eduardo Longo Fracalanzza, Lucia Martins Teixeira, Jorge Rezende-Filho, Penélope Saldanha Marinho, Joffre Amim Júnior, Stephen Taylor, Steve Thomas and Tatiana Castro Abreu Pinto
Pathogens 2022, 11(10), 1104; https://doi.org/10.3390/pathogens11101104 - 27 Sep 2022
Cited by 3 | Viewed by 2439
Abstract
Group B Streptococcus (GBS) is a leading cause of neonatal infections. The genitourinary and gastrointestinal tract of pregnant women are the main source of transmission to newborns. This work investigated the prevalence and characterized GBS from pregnant women in Rio de Janeiro, Brazil, [...] Read more.
Group B Streptococcus (GBS) is a leading cause of neonatal infections. The genitourinary and gastrointestinal tract of pregnant women are the main source of transmission to newborns. This work investigated the prevalence and characterized GBS from pregnant women in Rio de Janeiro, Brazil, comparing the periods before (January 2019 to March 2020; 521) and during (May 2020 to March 2021; 285) the COVID-19 pandemic. GBS was detected in 10.8% of anovaginal samples. Considering scenarios before and during the pandemic, GBS colonization rate significantly decreased (13.8% vs. 5.3%; p = 0.0001). No clinical and sociodemographic aspect was associated with GBS carriage (p > 0.05). A total of 80%, 13.8% and 4.6% GBS strains were non-susceptible to tetracycline, erythromycin and clindamycin, respectively. Serotype Ia was the most frequent (47.7%), followed by V (23.1%), II (18.4%), III (7.7%) and Ib (3.1%). An increasing trend of serotypes Ib and V, as well as of antimicrobial resistance rates, and a decreasing trend of serotypes II and III, were observed after the pandemic onset, albeit not statistically significant (p > 0.05). The reduction in GBS colonization rates and alterations in GBS serotypes and resistance profiles during the pandemic were not due to changes in the sociodemographic profile of the population. Considering that control and preventive measures related to the COVID-19 pandemic onset have impacted other infectious diseases, these results shed light on the need for the continuous surveillance of GBS among pregnant women in the post-pandemic era. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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10 pages, 905 KiB  
Article
Molecular Epidemiology of Group B Streptococci in Lithuania Identifies Multi-Drug Resistant Clones and Sporadic ST1 Serotypes Ia and Ib
by Jonah Rodgus, Ruta Prakapaite, Panagiotis Mitsidis, Ramune Grigaleviciute, Rita Planciuniene, Povilas Kavaliauskas and Elita Jauneikaite
Pathogens 2022, 11(9), 1060; https://doi.org/10.3390/pathogens11091060 - 17 Sep 2022
Cited by 2 | Viewed by 2115
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of neonatal infections. Yet, detailed assessment of the genotypic and phenotypic factors associated with GBS carriage, mother-to-baby transmission, and GBS infection in neonates and adults is lacking. Understanding the distribution of GBS genotypes, [...] Read more.
Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of neonatal infections. Yet, detailed assessment of the genotypic and phenotypic factors associated with GBS carriage, mother-to-baby transmission, and GBS infection in neonates and adults is lacking. Understanding the distribution of GBS genotypes, including the predominance of different serotypes, antimicrobial resistance (AMR) genes, and virulence factors, is likely to help to prevent GBS diseases, as well as inform estimates of the efficacy of future GBS vaccines. To this end, we set out to characterise GBS isolates collected from pregnant and non-pregnant women in Kaunas region in Lithuania. Whole genome sequences of 42 GBS isolates were analysed to determine multi-locus sequence typing (MLST), the presence of acquired AMR and surface protein genes, and the phylogenetic relatedness of isolates. We identified serotypes Ia (42.9%, 18/42), III (33.3%, 14/42), V (21.4%, 9/42), and a single isolate of serotype Ib. Genomic analyses revealed high diversity among the isolates, with 18 sequence types (STs) identified, including three novel STs. 85.7% (36/42) of isolates carried at least one AMR gene: tetM or tetO (35/42), ermB or lsaC (8/42) and ant6-Ia and aph3-III (2/42). This study represents the first genomic analysis of GBS isolated from women in Lithuania and contributes to an improved understanding of the global spread of GBS genotypes and phenotypes, laying the foundations for future GBS surveillance in Lithuania. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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16 pages, 4743 KiB  
Article
How GBS Got Its Hump: Genomic Analysis of Group B Streptococcus from Camels Identifies Host Restriction as well as Mobile Genetic Elements Shared across Hosts and Pathogens
by Chiara Crestani, Dinah Seligsohn, Taya L. Forde and Ruth N. Zadoks
Pathogens 2022, 11(9), 1025; https://doi.org/10.3390/pathogens11091025 - 8 Sep 2022
Cited by 1 | Viewed by 2601
Abstract
Group B Streptococcus (GBS) literature largely focuses on humans and neonatal disease, but GBS also affects numerous animals, with significant impacts on health and productivity. Spill-over events occur between humans and animals and may be followed by amplification and evolutionary adaptation in the [...] Read more.
Group B Streptococcus (GBS) literature largely focuses on humans and neonatal disease, but GBS also affects numerous animals, with significant impacts on health and productivity. Spill-over events occur between humans and animals and may be followed by amplification and evolutionary adaptation in the new niche, including changes in the core or accessory genome content. Here, we describe GBS from one-humped camels (Camelus dromedarius), a relatively poorly studied GBS host of increasing importance for food security in arid regions. Genomic analysis shows that virtually all GBS from camels in East Africa belong to a monophyletic clade, sublineage (SL)609. Capsular types IV and VI, including a new variant of type IV, were over-represented compared to other host species. Two genomic islands with signatures of mobile elements contained most camel-associated genes, including genes for metal and carbohydrate utilisation. Lactose fermentation genes were associated with milk isolates, albeit at lower prevalence in camel than bovine GBS. The presence of a phage with high identity to Streptococcus pneumoniae and Streptococcus suis suggests lateral gene transfer between GBS and bacterial species that have not been described in camels. The evolution of camel GBS appears to combine host restriction with the sharing of accessory genome content across pathogen and host species. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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9 pages, 253 KiB  
Article
Protective Effect of Lactobacillus crispatus against Vaginal Colonization with Group B Streptococci in the Third Trimester of Pregnancy
by Maja Starc, Miha Lučovnik, Petra Eržen Vrlič and Samo Jeverica
Pathogens 2022, 11(9), 980; https://doi.org/10.3390/pathogens11090980 - 27 Aug 2022
Cited by 4 | Viewed by 1729
Abstract
Background: A normal vaginal microbiota may protect the vaginal mucosa from colonization by potentially pathogenic bacteria, including group B streptococci (GBS). The aim of this study was to investigate the association between colonization with GBS and the presence of specific vaginal microbiota isolated [...] Read more.
Background: A normal vaginal microbiota may protect the vaginal mucosa from colonization by potentially pathogenic bacteria, including group B streptococci (GBS). The aim of this study was to investigate the association between colonization with GBS and the presence of specific vaginal microbiota isolated from vaginal swabs in the third trimester of pregnancy. Methods: A semiquantitative culture of 1860 vaginal swabs from consecutive pregnant women in their third trimester was analyzed. The dominant bacteria, including lactobacilli, were identified using MALDI-TOF mass spectrometry. An enrichment culture for GBS was performed on the swabs. GBS colonization correlated with the bacteria isolated at the same time. Results: Lactobacilluscrispatus was isolated in 27.5% of the cultures, followed by L. jensenii (13.9%), L. gasseri (12.6%), and L. iners (10.1%). The presence of lactobacilli as a group, and of L. crispatus, inversely correlated with GBS colonization (OR = 0.44 and OR = 0.5, respectively; both with p < 0.001). Other microorganisms, including Gardnerella vaginalis, mixed aerobic bacteria and yeasts, were not associated with GBS colonization. Conclusions: Lactobacilli, especially L. crispatus, may prevent GBS colonization in pregnancy. Maintaining a normal vaginal microbiota could be an effective method for the antibiotic-free prevention of invasive GBS infections in neonates. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
13 pages, 1380 KiB  
Article
Group B Streptococcus-Induced Macropinocytosis Contributes to Bacterial Invasion of Brain Endothelial Cells
by Eric R. Espinal, Teralan Matthews, Brianna M. Holder, Olivia B. Bee, Gabrielle M. Humber, Caroline E. Brook, Mustafa Divyapicigil, Jerod Sharp and Brandon J. Kim
Pathogens 2022, 11(4), 474; https://doi.org/10.3390/pathogens11040474 - 15 Apr 2022
Cited by 11 | Viewed by 2381
Abstract
Bacterial meningitis is defined as serious inflammation of the central nervous system (CNS) in which bacteria infect the blood–brain barrier (BBB), a network of highly specialized brain endothelial cells (BECs). Dysfunction of the BBB is a hallmark of bacterial meningitis. Group B Streptococcus [...] Read more.
Bacterial meningitis is defined as serious inflammation of the central nervous system (CNS) in which bacteria infect the blood–brain barrier (BBB), a network of highly specialized brain endothelial cells (BECs). Dysfunction of the BBB is a hallmark of bacterial meningitis. Group B Streptococcus (GBS) is one of the leading organisms that cause bacterial meningitis, especially in neonates. Macropinocytosis is an actin-dependent form of endocytosis that is also tightly regulated at the BBB. Previous studies have shown that inhibition of actin-dependent processes decreases bacterial invasion, suggesting that pathogens can utilize macropinocytotic pathways for invasion. The purpose of this project is to study the factors that lead to dysfunction of the BBB. We demonstrate that infection with GBS increases rates of endocytosis in BECs. We identified a potential pathway, PLC-PKC-Nox2, in BECs that contributes to macropinocytosis regulation. Here we demonstrate that downstream inhibition of PLC, PKC, or Nox2 significantly blocks GBS invasion of BECs. Additionally, we show that pharmacological activation of PKC can turn on macropinocytosis and increase bacterial invasion of nonpathogenic yet genetically similar Lactococcus lactis. Our results suggest that GBS activates BEC signaling pathways that increase rates of macropinocytosis and subsequently the invasion of GBS. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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12 pages, 1236 KiB  
Article
Rectovaginal Colonization with Serotypes of Group B Streptococci with Reduced Penicillin Susceptibility among Pregnant Women in León, Nicaragua
by Teresa Alemán, Nadja A. Vielot, Roberto Herrera, Reymundo Velasquez, Tatiana Berrios, Christian Toval-Ruíz, Evert Téllez, Andres Herrera, Samir Aguilar, Sylvia Becker-Dreps, Neil French and Samuel Vilchez
Pathogens 2022, 11(4), 415; https://doi.org/10.3390/pathogens11040415 - 29 Mar 2022
Cited by 2 | Viewed by 2297
Abstract
Group B Streptococci (GBS) are important causes of neonatal sepsis and meningitis globally. To elucidate the potential benefits of maternal GBS vaccines, data is needed on the epidemiology of maternal GBS rectovaginal colonization, distribution of serotypes, and resistance to intrapartum antibiotic prophylaxis (IAP). [...] Read more.
Group B Streptococci (GBS) are important causes of neonatal sepsis and meningitis globally. To elucidate the potential benefits of maternal GBS vaccines, data is needed on the epidemiology of maternal GBS rectovaginal colonization, distribution of serotypes, and resistance to intrapartum antibiotic prophylaxis (IAP). We collected rectal and vaginal samples from 305 pregnant women in León, Nicaragua between 35 and 40 weeks gestation. Samples were cultured for GBS and confirmed using latex agglutination. GBS isolates underwent serotyping by quantitative polymerase chain reaction, and antimicrobial susceptibility testing by disk diffusion and microdilution following Clinical Laboratory Standard Institute guidelines. Sixty-three women (20.7%) were colonized with GBS in either the rectum or the vagina. Of 91 GBS isolates collected from positive cultures, most were serotypes II (28.6%), Ia (27.5%), and III (20.9%). Most GBS isolates (52.9%) were resistant to penicillin, the first-line prophylactic antibiotic. Penicillin resistance was highly correlated with resistance to vancomycin, ceftriaxone, and meropenem. The results of our study suggest that one-fifth of pregnant women in the urban area of León, Nicaragua are colonized with GBS and risk transmitting GBS to their offspring during labor. High resistance to commonly available antibiotics in the region suggests that prophylactic maternal GBS vaccination would be an effective alternative to IAP. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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11 pages, 1178 KiB  
Article
Colonization of Group B Streptococcus in Pregnant Women and Their Neonates from a Sri Lankan Hospital
by Dulmini Nanayakkara Sapugahawatte, Carmen Li, Veranja Liyanapathirana, Chaminda Kandauda, Champika Gihan, Chendi Zhu, Norman Wai Sing Lo, Kam Tak Wong and Margaret Ip
Pathogens 2022, 11(4), 386; https://doi.org/10.3390/pathogens11040386 - 23 Mar 2022
Cited by 4 | Viewed by 3065
Abstract
We investigated the molecular epidemiology of Streptococcus agalactiae (Group B Streptococcus, GBS) from carriage in a cohort of pregnant mothers and their respective newborns in a Teaching Hospital in Sri Lanka. GBS vaginal carriage was assessed on pregnant mothers at pre-delivery ( [...] Read more.
We investigated the molecular epidemiology of Streptococcus agalactiae (Group B Streptococcus, GBS) from carriage in a cohort of pregnant mothers and their respective newborns in a Teaching Hospital in Sri Lanka. GBS vaginal carriage was assessed on pregnant mothers at pre-delivery (n = 250), post-delivery (n = 130), and from peri-rectal swabs of neonates (n = 159) in a prospective study. All colonizing, non-duplicate GBS isolates (n = 60) were analyzed for antimicrobial susceptibilities, capsular serotyping, and whole-genome sequencing (WGS). The percentage of GBS carriage in mothers in the pre-delivery and post-delivery cohorts were 11.2% (n = 28) and 19.2% (n = 25), respectively, and 4.4% (n = 7) in neonates. GBS isolates predominantly belonged to serotype VI (17/60, 28.3%). The isolates spanned across 12 sequence types (STs), with ST1 (24/60, 40%) being the most predominant ST. Concomitant resistance to erythromycin, tetracyclines, and gentamicin was observed in eight strains (13.3%). WGS revealed the presence of antimicrobial resistance genes including ermA (5/60), mefA (1/60), msrD (1/60), and tetLMO (2/60, 28/60, and 1/60, respectively) among 60 strains. The study provides insight into the diversity of vaccine targets of GBS since serotype VI is yet to be covered in the vaccine development program. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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15 pages, 2722 KiB  
Article
Optimization of Streptococcus agalactiae Biofilm Culture in a Continuous Flow System for Photoinactivation Studies
by Michal K. Pieranski, Michal Rychlowski and Mariusz Grinholc
Pathogens 2021, 10(9), 1212; https://doi.org/10.3390/pathogens10091212 - 18 Sep 2021
Cited by 4 | Viewed by 2709
Abstract
Streptococcus agalactiae is a relevant cause of neonatal mortality. It can be transferred to infants via the vaginal tract and cause meningitis, pneumonia, arthritis, or sepsis, among other diseases. The cause of therapy ineffectiveness and infection recurrence is the growth of bacteria as [...] Read more.
Streptococcus agalactiae is a relevant cause of neonatal mortality. It can be transferred to infants via the vaginal tract and cause meningitis, pneumonia, arthritis, or sepsis, among other diseases. The cause of therapy ineffectiveness and infection recurrence is the growth of bacteria as biofilms. To date, several research teams have attempted to find a suitable medium for the cultivation of S. agalactiae biofilms. Among others, simulated vaginal fluid has been used; however, biofilm production in this medium has been found to be lower than that in tryptic soy broth. We have previously shown that S. agalactiae can be successfully eradicated by photoinactivation in planktonic culture, but there have been no studies on biofilms. The aim of this study was to optimize S. agalactiae biofilm culture conditions to be used in photoinactivation studies. We compared biofilm production by four strains representing the most common serotypes in four different broth media with crystal violet staining. Then, we evaluated stationary biofilm culture in microtiter plates and biofilm growth in a CDC Biofilm Reactor® (BioSurface Technologies, Bozeman, MT, USA) under continuous flow conditions. Subsequently, we applied Rose Bengal-mediated photoinactivation to both biofilm models. We have shown that photoinactivation is efficient in biofilm eradication and is not cyto/phototoxic to human keratinocytes. We found conditions allowing for stable and repetitive S. agalactiae biofilm growth in continuous flow conditions, which can be successfully utilized in photoinactivation assays and potentially in all other antibacterial studies. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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8 pages, 221 KiB  
Article
Poor Adherence to the Screening-Based Strategy of Group B Streptococcus Despite Colonization of Pregnant Women in Greece
by Maria Maroudia Berikopoulou, Aikaterini Pana, Theodota Liakopoulou-Tsitsipi, Nikos F. Vlahos, Vasiliki Papaevangelou and Alexandra Soldatou
Pathogens 2021, 10(4), 418; https://doi.org/10.3390/pathogens10040418 - 1 Apr 2021
Cited by 3 | Viewed by 1728
Abstract
Group B streptococcus (GBS) is a leading cause of serious neonatal infections. Maternal GBS colonization is associated with early- and late-onset neonatal disease (EOD/LOD). In Greece, a screening-based strategy is recommended, in which concurrent vaginal-rectal cultures should be obtained between 36 0/7 and [...] Read more.
Group B streptococcus (GBS) is a leading cause of serious neonatal infections. Maternal GBS colonization is associated with early- and late-onset neonatal disease (EOD/LOD). In Greece, a screening-based strategy is recommended, in which concurrent vaginal-rectal cultures should be obtained between 36 0/7 and 37 6/7 weeks’ gestation. We sought to examine the level of adherence to the GBS screening guidelines and estimate the prevalence of GBS colonization among pregnant women. Although in Greece the screening-based strategy is followed, we also examined known EOD risk factors and linked them to GBS colonization. A cross-sectional study of 604 women postpartum in three hospitals and maternity clinics was conducted. Following written informed consent, data were collected via a short self-completed questionnaire and review of patients’ records. In 34.6% of the enrolled pregnant women, no culture had been taken. Of the remaining, 12.8% had proper vaginal-rectal sample collections. The overall maternal colonization rate was 9.6%. At least one risk factor for EOD was identified in 12.6% of participants. The presence of risk factors was associated with positive cultures (p = 0.014). The rate of culture collection did not differ between women with or without an EOD risk factor. Adherence to a universal screening of pregnant women with vaginal-rectal cultures was poor. Despite probable underestimation of GBS carrier status, almost 1 in 10 participants were GBS positive during pregnancy. Screening of women with risk factors for EOD should, at least, be prioritized to achieve prevention and prompt intervention of EOD. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))

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24 pages, 1076 KiB  
Review
Strategies to Prevent Early and Late-Onset Group B Streptococcal Infection via Interventions in Pregnancy
by Mahin Delara, Nirma Khatri Vadlamudi and Manish Sadarangani
Pathogens 2023, 12(2), 229; https://doi.org/10.3390/pathogens12020229 - 1 Feb 2023
Cited by 4 | Viewed by 3155
Abstract
Group B Streptococcus is a Gram-positive bacterium that typically colonizes 10–30% of pregnant women, causing chorioamnionitis, preterm birth, and stillbirth, as well as neonatal sepsis and meningitis with early-onset disease (EOD) or late-onset disease (LOD) due to ascending infection or transmission during delivery. [...] Read more.
Group B Streptococcus is a Gram-positive bacterium that typically colonizes 10–30% of pregnant women, causing chorioamnionitis, preterm birth, and stillbirth, as well as neonatal sepsis and meningitis with early-onset disease (EOD) or late-onset disease (LOD) due to ascending infection or transmission during delivery. While there are some differences between EOD and LOD in terms of route of transmission, risk factors, and serotypes, the only preventive approach currently is maternal intrapartum antibiotic prophylaxis (IAP) which will not be able to fully address the burden of the disease since this has no impact on LOD. Probiotics and immunization in pregnancy may be more effective than IAP for both EOD and LOD. There is mixed evidence of probiotic effects on the prevention of GBS colonization, and the data from completed and ongoing clinical trials investigating different GBS vaccines are promising. Current vaccine candidates target bacterial proteins or the polysaccharide capsule and include trivalent, tetravalent, and hexavalent protein–polysaccharide conjugate vaccines. Some challenges in developing novel GBS vaccines include the lack of a correlate of protection, the potential for serotype switching, a need to understand interactions with other vaccines, and optimal timing of administration in pregnancy to maximize protection for both term and preterm infants. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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9 pages, 583 KiB  
Systematic Review
Group B Streptococcus among Pregnant Women and Neonates in Saudi Arabia: A Systemic Review
by Amer Alshengeti
Pathogens 2022, 11(9), 1029; https://doi.org/10.3390/pathogens11091029 - 10 Sep 2022
Cited by 1 | Viewed by 1534
Abstract
Sepsis caused by Group B Streptococcus (GBS) continues to cause mortality and morbidity in newborns, especially in developing countries. Bacterial sepsis in newborns varies nationally and even within countries. Developing countries have reported 34 deaths per 1000 live births compared to 5 in [...] Read more.
Sepsis caused by Group B Streptococcus (GBS) continues to cause mortality and morbidity in newborns, especially in developing countries. Bacterial sepsis in newborns varies nationally and even within countries. Developing countries have reported 34 deaths per 1000 live births compared to 5 in developed countries. This systemic review aimed to assess the prevalence of GBS colonization among pregnant women and the incidence of neonatal GBS sepsis in Saudi Arabia. A literature search of PubMed, MEDLINE Ovid, and Google Scholar was conducted. A total of 21 studies were found: 15 described maternal GBS colonization and 6 studies described neonatal GBS infections. The GBS colonization prevalence among pregnant women ranged from 2.1% to 32.8%. Inconsistencies in the reporting method for neonatal GBS infection rates were observed. Only two studies have the incidence of neonatal GBS as the primary outcome. No national multicenter studies exist on the GBS rates among neonates. Nationwide studies are warranted to assess the burden of GBS infections in neonates. These studies would guide appropriate GBS screening strategies during pregnancy for application in a national public health program. Full article
(This article belongs to the Special Issue Group B-Streptococcus (GBS))
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