Using Surface Immunogenic Protein as a Carrier Protein to Elicit Protective Antibody to Multiple Serotypes for Candidate Group B Streptococcal Glycan Conjugate Vaccines.

Group B Streptococcus (GBS) is a life-threatening opportunistic pathogen, particularly in pregnant women, infants, and the elderly. Currently, maternal vaccination is considered the most viable long-term option for preventing GBS mother-to-infant infection, and two polysaccharide conjugate vaccines utilizing CRM197 as a carrier protein have undergone clinical phase II trials. Surface immunogenic protein (Sip), present in all identified serotypes of GBS strains so far, is a protective surface protein of GBS. In this study, the type Ia capsular polysaccharide (CPS) of GBS was utilized as a model to develop candidate antigens for a polysaccharide conjugate vaccine by coupling it with the Sip of GBS and the traditional carrier protein CRM197. Serum analysis from immunized New Zealand rabbits and CD1 mice revealed that there was no significant difference in antibody titers between the Ia-Sip group and Ia-CRM197 group; however, both were significantly higher than those observed in the Ia polysaccharide group. Opsonophagocytosis and passive immune protection results using rabbit serum indicated no significant difference between the Ia-Sip and Ia-CRM197 groups, both outperforming the Ia polysaccharide group. Furthermore, serum from the Ia-Sip group had a cross-protective effect on multiple types of GBS strains. The challenge test results in CD1 mice demonstrated that the Ia-Sip group provided complete protection against lethal doses of bacteria and also showed cross-protection against type III strain. Our study demonstrates for the first time that Ia-Sip is immunogenic and provides serotype-independent protection in glycan conjugate vaccines, which also indicates Sip may serve as an excellent carrier protein for GBS glycan conjugate vaccines and provide cross-protection against multiple GBS strains.

Adherence to universal screening for group B Streptococcus in pregnancy and prevalence of colonised pregnancies in Caserta province, Italy.

Group B Streptococcus (Streptococcus agalactiae; GBS) infection is a significant contributor to neonatal morbidity and mortality. In the early 1970s, the neonatal mortality rate for infants with invasive GBS disease was 55%. With the adoption of the first medical community guidelines to prevent GBS infection in the 1990s, the mortality rate decreased to approximately 5%. The main obstetric procedure for preventing vertical transmission of GBS infection involves universal screening of pregnant women using a vaginal-rectal swab (VRS) to identify those eligible for intrapartum antibiotic prophylaxis (IAP). The study analyzes the adherence of screening and the trend of GBS infection in pregnancy in the province of Caserta, Italy. Data were obtained from pregnant women who gave birth in a first level birthing center in 2022 from birth assistance certificate (CEDAP), obstetric and neonatal record. Postnatal evaluation collected through computer-assisted telephone interviews. 567 women delivered at our center during the study period. The average coverage of GBS testing in pregnancy was 99.2% (562), and the proportion of GBS colonised women was 12.6% (71) according with the national average, which is about 10-20%. The spread of positive cases appears to fluctuate among the various groups of pregnant women studied, indicating no significant statistical variance among presence of a partner, among women who have given birth multiple times, among Italian nationals, or across different ages, but a significant statistical excess is evident among mothers with less education. In 93% (66) of GBS carrier mothers, intrapartum antibiotic prophylaxis (IAP) was administered correctly, regardless of the type of delivery performed. Despite the successful integration of GBS screening, a significant gap remains between the ideal scenario and the actual implementation of IAP. At the three-month assessment, no child required hospitalization, consistent with the relatively low incidence of invasive GBS infection. Nevertheless, for those who are not eligible to VRS screening, such as preterm birth, or IAP, as in precipitous birth, the identification of biomarkers enabling early recognition of invasive GBS disease remains essential. Additionally, the emergence of vaccines administered during gestation, conferring passive immunity to newborns represents a promising possible new direction. Therefore, to ensure the practical application of GBS screening and actual IAP by healthcare providers, periodic audits and regular monitoring should be encouraged.

Group B Streptococcus Persistently Colonizing the Adenosquamous Carcinoma of the Lung: A Blessing in Disguise?

Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a gram-negative, beta-hemolytic facultative anaerobe that causes neonatal pneumonia and sepsis. The neoplastic epithelial cells in adults, especially those of squamous origin, can show special adhesive properties toward GBS, which tends to reside within these tumors. There are some animal and human studies proving this association. Here, we present a 64-year-old female patient who had lung carcinoma of mixed adeno and squamous origin found to have persistent GBS every time the bronchoscopy was done for tumor ablation or cryotherapy. Subsequently, after starting her on chemo-radiotherapy, she also presented with multiple episodes of pneumonia caused by GBS and Pseudomonas aeruginosa. Moreover, many animal studies have shown the anti-tumor properties of GBS toxin that can prevent its metastasis and stop vascular growth surrounding the tumor. This property of GBS toxin can prove a blessing in disguise.

Introducing Triplex Forming Oligonucleotide into Loop-Mediated Isothermal Amplification for Developing a Lateral Flow Biosensor for Streptococci Detection.

Loop-mediated isothermal amplification (LAMP) technology is extensively utilized for the detection of infectious diseases owing to its rapid processing and high sensitivity. Nevertheless, conventional LAMP signaling methods frequently suffer from a lack of sequence specificity. This study integrates a triplex-forming oligonucleotide (TFO) probe into the LAMP process to enhance sequence specificity. This TFO-LAMP technique was applied for the detection of Group B Streptococcus (GBS). The TFO probe is designed to recognize a specific DNA sequence, termed the TFO targeting sequence (TTS), within the amplified product, facilitating detection via fluorescent instrumentation or lateral flow biosensors. A screening method was developed to identify TFO sequences with high affinity to integrate TFO into LAMP, subsequently incorporating a selected TTS into an LAMP primer. In the TFO-LAMP assay, a FAM-labeled TFO is added to target the TTS. This TFO can be captured by an anti-FAM antibody on lateral flow test strips, thus creating a nucleic acid testing biosensor. The efficacy of the TFO-LAMP assay was confirmed through experiments with specimens spiked with varying concentrations of GBS, demonstrating 85% sensitivity at 300 copies and 100% sensitivity at 30,000 copies. In conclusion, this study has successfully developed a TFO-LAMP technology that offers applicability in lateral flow biosensors and potentially other biosensor platforms.

Molecular typing and antimicrobial resistance of group B Streptococcus clinical isolates in Saudi Arabia.

OBJECTIVES: Group B Streptococcus (GBS) has emerged as an important cause of severe infections in adults. However, limited data are available regarding the epidemiology of GBS in Saudi Arabia. METHODS: Isolates were collected over a period of eight months from colonized (n = 104) and infected adults (n = 95). Serotypes and virulence determinants were detected by polymerase chain reactions (PCRs). Genetic relatedness was assessed using Multiple Locus Variable Number Tandem Repeat Analysis (MLVA). Antimicrobial susceptibilities were determined by disk diffusion. RESULTS: Serotypes III and V (25% each) were the most prevalent, followed by serotypes II (16.18%), Ia (13.24%), VI (9.31%), and Ib (8.82%), while five isolates remained non-typeable (2.45%). Hypervirulent serotype III/CC17 clone (n = 21) accounted for 41.18% of the serotype III isolates. Most isolates (53.92%) harboured pilus island (PI) 1 and 2a types, while PI-2b was predominantly detected in the hypervirulent clone. Isolates were variably resistant to tetracycline (76.47%), erythromycin (36.76%), clindamycin (25.49%), and levofloxacin (6.37%), but remained susceptible to penicillin. Macrolide resistant isolates exhibited constitutive (55.42%) and inducible macrolide-lincosamide-streptogramin B resistance phenotypes (33.74%), while a few had L (9.64%) or M (1.2%) phenotypes. MLVA patterns of dominant serotypes III and V revealed 40 different types divided into 12 clusters and 28 singletons. Interestingly, macrolide resistance was significantly associated with two major MLVA types. CONCLUSIONS: GBS isolates belonged predominantly to serotypes III and V, but there were no clear associations between serotypes and patient groups. The studied isolates exhibited high levels of resistance to erythromycin and clindamycin that need further surveillance.

Cost-effectiveness analysis of maternal vaccination against Group B streptococcus in Japan.

Background: Group B Streptococcus (GBS) is a leading pathogen causing life-threatening bacterial infections in neonates (early- or late-onset) and infants, and is associated with preterm and stillbirth. Japan introduced national guidelines to reduce early-onset neonatal GBS disease, with universal prenatal screening and intrapartum antimicrobial prophylaxis (IAP). However, screening/IAP does not prevent GBS associated late-onset disease, preterm or stillbirth. Maternal GBS vaccines in development are targeted at infant GBS disease but may provide benefit across perinatal outcomes. We aimed to assess cost-effectiveness of a future maternal GBS vaccine, for a base case prevention of infant GBS disease in combination with screening/IAP compared to screening/IAP alone. Methods: We used a decision tree model to estimate cases of infant GBS disease, deaths, and neuro-developmental impairment (NDI), GBS-related stillbirths, and the associated costs and loss in Quality-Adjusted Life Years (QALYs). We calculate the threshold price at which a vaccine would be cost-effective assuming a cost-effectiveness threshold of ¥5 million/QALY. We explored the potential benefit of a maternal GBS vaccine that also prevents preterm birth in a scenario analysis. Results: Maternal GBS vaccination in Japan could prevent an additional 142 infant GBS cases annually, including 5 deaths and 21 cases of NDI, and 13 stillbirths compared to screening/IAP alone. The incremental cost-effectiveness ratio (ICER) was ¥3.78 million/QALY with a vaccine cost of ¥5,000/dose. If the QALY lost for stillbirth is included, the ICER is reduced to ¥1.78 million/QALY. Median threshold vaccine price was ¥6,900 per dose (95 % uncertainty interval ¥5,100 to ¥9,200 per dose). If maternal GBS vaccination also prevented half of GBS-associated preterm, the ICER would be reduced to ¥1.88 million/QALY. Conclusions: An effective maternal GBS vaccine is likely to be considered cost-effective in Japan at a price of ¥5,000/dose. Effectiveness against other adverse perinatal outcomes would increase health benefits and cost-effectiveness.

Phenotypic and genotypic comparison of pathogenic group B Streptococcus isolated from human and cultured tilapia (Oreochromis species) in Malaysia.

Group B Streptococcus (GBS) is a major cause of several infectious diseases in humans and fish. This study was conducted to compare human and fish-derived GBS in terms of their antimicrobial susceptibility, serotype, virulence and pili genes and sequence type (ST), and to determine whether there is a potential linkage of zoonotic transmission in Malaysia. GBS isolated from humans and fish had similar phenotypic characteristics and differed in virulence gene profile, antimicrobial susceptibility, serotype and sequence type. Fish GBS isolates had lower genetic diversity and higher antibiotic susceptibility than human isolates. We report a rare detection of the potentially fish-adapted ST283 in human GBS isolates. Both human and fish ST283 shared several phenotypic and genotypic features, including virulence and pilus genes and antimicrobial susceptibility, illustrating the value of monitoring GBS within the One Health scope. In this study, two human GBS ST283 isolates belonging to the variant common in fish hosts were identified, raising awareness of the zoonotic potential between the different species in Malaysia.

Host inflammatory dynamics reveal placental immune modulation by Group B Streptococcus during pregnancy.

Group B Streptococcus (GBS) is a pathobiont that can ascend to the placenta and cause adverse pregnancy outcomes, in part through production of the toxin ß-hemolysin/cytolysin (ß-h/c). Innate immune cells have been implicated in the response to GBS infection, but the impact of ß-h/c on their response is poorly defined. We show that GBS modulates innate immune cell states by subversion of host inflammation through ß-h/c, allowing worse outcomes. We used an ascending mouse model of GBS infection to measure placental cell state changes over time following infection with a ß-h/c-deficient and isogenic wild type GBS strain. Transcriptomic analysis suggests that ß-h/c-producing GBS elicit a worse phenotype through suppression of host inflammatory signaling in placental macrophages and neutrophils, and comparison of human placental macrophages infected with the same strains recapitulates these results. Our findings have implications for identification of new targets in GBS disease to support host defense against pathogenic challenge.

Infective Endocarditis Due to Streptococcus agalactiae Complicated by a Complete Atrioventricular Block.

Infective endocarditis due to Streptococcus (S.) agalactiae is an uncommon but potentially life-threatening condition. We report a case of infective endocarditis due to S. agalactiae in a 79-year-old woman who presented with fatigue and appetite loss. The results of blood cultures and the vegetation detected by transesophageal echocardiography led us to the diagnosis. She was started on prompt and appropriate antibiotic therapy. Despite her favorable clinical course, she suddenly developed a complete atrioventricular block after one week of conservative treatment. She then underwent surgery with abscess drainage along with aortic and mitral valve replacement. Intraoperative findings revealed that the perivalvular inflammation insidiously extended to the cardiac conduction system and caused a complete heart block. Our case highlights the high virulence of S. agalactiae, requiring more vigilance among clinicians.

A Case of Late-Onset Group B Streptococcus Serotype â b Meningitis With Absence of Pleocytosis at the Initial Cerebrospinal Fluid Analysis.

Bacterial meningitis in infants is a life-threatening illness that survives significant neurological sequelae that remain in survivors. The current diagnostic gold standard for meningitis is bacterial isolation from culture or molecular diagnostics in the cerebrospinal fluid. The decision for antibiotics therapy before bacterial detection is made on microscopic and biochemical findings in the cerebrospinal fluid, however, some patient shows no microscopic finding and pleocytosis at the initial cerebrospinal fluid analysis. Herein, we report a case of late-onset group B Streptococcus serotype Ib meningitis that could be introduced with timelier antibiotic therapy even in the absence of pleocytosis without the detection of bacteria on smear at the initial CSF analysis.

Multicenter Evaluation of the Cepheid Xpert GBS LB XC Test.

Early-onset neonatal sepsis due to Streptococcus agalactiae (group B Streptococcus [GBS]) infection is one of the leading causes of newborn mortality and morbidity. The latest guidelines published in 2019 recommended universal screening of GBS colonization among all pregnant women and intrapartum antibiotic prophylaxis for positive GBS. The updated procedures allow rapid molecular-based GBS screening using nutrient broth-enriched rectovaginal samples. Commercially available molecular assays for GBS diagnosis target mainly the cfb gene, which encodes a hemolysin protein responsible for producing the Christie-Atkins-Munch-Petersen (CAMP) factor. cfb is considered a conserved gene in essentially all GBS isolates. However, false-negative GBS results on Cepheid Xpert GBS and GBS LB tests due to deletions in or near the region that encodes cfb were reported recently. Therefore, the new Xpert GBS LB XC test was developed. This study is a multicenter evaluation of the new test for GBS identification from nutrient broth-enriched rectal/vaginal samples from antepartum women. A total of 621 samples were prospectively enrolled. The samples were tested with the Xpert GBS LB XC test, the composite comparator method, which included the Hologic Panther Fusion GBS test combined with bacterial culture, followed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identification, and bacterial culture alone, followed by MALDI-TOF MS identification. The respective sensitivity and specificity of the Xpert GBS LB XC test were 99.3% and 98.7% compared to the composite comparator method and 99.1% and 91.8% compared to bacterial culture alone with MALDI-TOF MS identification. Overall, the Xpert GBS LB XC test performed comparatively to the composite comparator method and is equivalent to traditional bacterial culture followed by MALDI-TOF MS.

Differential Interaction between Invasive Thai Group B Streptococcus Sequence Type 283 and Caco-2 Cells.

The emergence in Southeast Asia of invasive group B Streptococcus (GBS) infections in adults by sequence type (ST) 283 is suggested to be associated with fish consumption. Genotyping of 55 GBS clinical isolates revealed that 33/44 invasive isolates belonged to ST283/capsular polysaccharide type (CPS) III. This included 15/16 isolates recovered from younger adults aged 16-36 years. Seven ST283/CPSIII isolates from the blood, cerebrospinal fluid, or joint fluid were selected by the patient's age at random to perform interaction studies with intestinal epithelial Caco-2 monolayers. The invasion efficiency profiles from this study classified these isolates into two groups; a higher invasion efficiency group 1 recovered from patients aged between 23 and 36 years, and a lower invasion efficiency group 2 recovered from the elderly and neonate. Intracellular survival tests revealed that only group 1 members could survive inside Caco-2 cells up to 32 h without replication. Additionally, all isolates tested were able to traverse across polarized Caco-2 monolayers. However, the timing of translocation varied among the isolates. These results indicated the potential of GBS invasion via the gastrointestinal tract and showed phenotypic variations in invasiveness, intracellular survival, and translocation efficiency between genetically closely related ST283 isolates infecting young adults and those infecting the elderly.

Evaluation of appropriate vancomycin prescribing for the prevention of newborn group B streptococcal infections in a community hospital obstetrics service.

OBJECTIVES: The 2019 American College of Obstetricians and Gynecologists (ACOG) guidelines update for the prevention of perinatal group B Streptococcus (GBS) infections stipulate that vancomycin should be reserved to treat penicillin-allergic women at high risk for anaphylaxis with documented GBS resistance to clindamycin. Protocols and policies were adapted at the community hospital to incorporate these new guidelines. The primary objective of this research was to evaluate institutional compliance to these guidelines and secondarily, clinical outcomes. METHODS: Clinical pharmacists, in collaboration with an obstetrician, performed this hospital-based study. All instances of intravenous (IV) vancomycin therapy in GBS-positive patients were assessed from 1/1/2018 through 1/1/2021 and compared to the 2010 and 2019 ACOG guidelines. Treatment was analyzed to determine the appropriateness of both indication for use and dosage regimen as co-primary endpoints. Secondary endpoints included renal monitoring parameters, suspected adverse reactions, and early onset GBS disease in newborns, specifically sepsis, meningitis, and/or pneumonia. RESULTS: L&D admissions during the study period included 15,129 patients. All 30 L&D patients who received IV vancomycin for GBS prophylaxis were included in the study. This project demonstrated low compliance to the ACOG guidelines and identified previously unrecognized opportunities for improvement. CONCLUSIONS: The low compliance observed in this study, with the exception of documenting GBS status, occurred in spite of hospital adoption of a GBS order set, an updated vancomycin protocol and targeted education of clinical pharmacists. Assessment of the causes of noncompliance identified several potential corrective actions, especially in ordering and monitoring vancomycin.

Molecular determination, serotyping, antibiotic profile and virulence factors of group B Streptococcus isolated from invasive patients at Arabcare Hospital Laboratory, Palestine.

BACKGROUND: Streptococcus agalactiae (group B Streptococcus) is beta-hemolytic, catalase negative, gram-positive cocci, recognized as main bacterial pathogen causing infections in newborns, infants, adults, and elderly people around the world. The aim of this study is to investigate group B Streptococcus samples recovered from invasive patients and determine serotype, virulent genes, and antibiotic-resistant profile of Streptococcus agalactiae in Palestine. METHODS: A total of 95 group B Streptococcus strains were isolated from neonates, infants, pregnant and non-pregnant women and males at Arabcare Hospital Laboratory, Palestine, between the period of June 2018 and September 2020. Species identification was carried out through cultivation and conventional biochemical tests. A conventional Polymerase Chain Reaction (cPCR) was used to determine the 5 serotypes and virulent genes of the Streptococcus agalactiae strains. The antibiotic resistance test of group B Streptococcus was evaluated using Kirby-Bauer disk susceptibility. Sequencing and BLAST analysis were used to determine the relationship of the isolates in this study to worldwide isolates. RESULTS: Serotype III (35%) was the major group B Streptococcus strains serotype causing invasive infections in neonates, infants, pregnant and nonpregnant women, and males, followed by serotypes V (19%), Ia, and II (15%), Ib (6%), respectively. All our isolates encoding for surface protein virulent factors, including a highly virulent gene (HvgA) were mostly found in strains isolated from pregnant women (12%). These group B Streptococcus strains exhibited a high rate of resistance to clindamycin (26%). The overall percentage of levofloxacin resistance was 11%, while vancomycin and ampicillin showed higher resistance, at 14.7 and 16% respectively. In addition, the phylogenetic relationship dendrogram illustrates that Streptococcus agalactiae isolated from an invasive patient (newborn) in Palestine was similar to strains found in China and Japan. CONCLUSIONS: The outcomes of this study demonstrate that resistant group B Streptococcus strains are common in Palestine, therefore, evidence-based infection prevention and antibiotic stewardship efforts are necessary.

High rates of colonization and antimicrobial resistance of group B streptococcus highlight the need for vaccination even after implementation of guidelines for intrapartum antibiotic prophylaxis.

INTRODUCTION: It is estimated that about 11-35% of pregnant women are colonized with Group B streptococcus. Intrapartum antibiotic prophylaxis (IAP) is the primary intervention to decrease the risk of infecting babies born to GBS colonized mothers. METHODS: A total of 5,996 pregnant women, who received the Taiwanese universal GBS screening program from 2012 to 2020, were included in this study that investigated GBS colonization, antimicrobial resistance rates and their neonatal incidence of invasive GBS infection. RESULTS: The average GBS colonization rate was 18.5%. Older age groups had higher colonization rates than younger age groups. Compared to Taiwanese, immigrant women from Indonesia had a greater positive rate. GBS isolated from Vietnamese women had significant greater resistance to clindamycin relative to Taiwanese women. Rates of resistance to erythromycin increase from 35.5% to 45.5% over the 9 years of measurements. The incidence of invasive GBS disease was about 0.6/1,000 (4/6,204) live births during the study. CONCLUSIONS: Although relatively low incidence of invasive GBS diseases was observed after implementation of IAP, the colonization of GBS remains high and antimicrobial resistance of GBS is increasing. An effective GBS vaccine holds promise to be a solution for these issues.

Case Report: Prolonged CSF PCR Positivity in a Neonate With GBS Meningitis.

Bacterial meningitis is one of the critical diseases that needs to be diagnosed and treated promptly. Recent diagnostics of high sensitivity and specificity rates, such as PCR, helped with such presentation, especially in cases with prior antibiotics that led to culture negativity. However, the time window of PCR positivity is not well-studied, with scattered reports of different periods of positivity. Here, we report a case of neonatal GBS meningitis with positive PCR for more than 80 days from starting antibiotics.

Optimization of Streptococcus agalactiae Biofilm Culture in a Continuous Flow System for Photoinactivation Studies.

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.

Ruptured Renal Abscess From Streptococcus agalactiae Invasion in a Postpartum Female.

Streptococcus agalactiae (Group B Streptococcus or GBS)is an exceptionally rare causative organism of a ruptured renal abscess. We report a case of this normally commensal organism causing a large ruptured renal abscess in a 17-year-old postpartum female. Although S. agalactiae is known to cause postpartum neonatal morbidity and mortality, it has rarely caused invasive infections in the last 20 years in adults. While this diagnosis often presents with nonspecific findings that can easily be overlooked during the postpartum period, the patient responded well to the established treatment of broad-spectrum antibiotics and a percutaneous drain.