1
|
Bjerkhaug AU, Ramalingham S, Mboizi R, Le Doare K, Klingenberg C. The immunogenicity and safety of Group B Streptococcal maternal vaccines: A systematic review. Vaccine 2024; 42:84-98. [PMID: 38072754 DOI: 10.1016/j.vaccine.2023.11.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 01/01/2024]
Abstract
PURPOSE To systematically review immunogenicity and safety data of maternal group B streptococcal (GBS) vaccines in published clinical trials until July 2023. METHODS EMBASE, MEDLINE, Cochrane Library and clinicaltrial.gov. databases were searched for clinical studies that reported immunogenicity and/or safety of GBS vaccine in non-pregnant adults, pregnant women and infants between 1st of January 1996 to 31st of July 2023. Pairs of reviewers independently selected, data extracted, and assessed the risk of bias of the studies. Discrepancies were resolved by consensus. (PROSPERO CRD42020185213). RESULTS We retrieved 1472 records from the literature search; 20 studies and 6 sub-studies were included, involving 4440 non-pregnant participants and 1325 pregnant women with their newborns. There was a significantly higher IgG Geometric Mean Concentration (GMC) and IgG placental transfer ratios in vaccinated compared to placebo groups, with peak response 4-8 weeks after vaccination. Placental transfer ratio varied from 0.4 to 1.4 across five studies. The different clinical trials used different assays that limited direct comparison. There were no significant differences in the risk of serious adverse events (adjusted OR 0.73; 95 % CI 0.49-1.07), serious adverse events leading to withdrawal (adjusted OR 0.44; 95 % CI 0.13-1.51), and systemic illness or fever (adjusted OR 1.05; 95 % CI 0.26-4.19) between the vaccine and placebo groups. CONCLUSIONS The published clinical trials show significant IgG GMC response in subjects receiving the conjugated capsular polysaccharide and surface subunit protein vaccines compared to placebo. In current clinical trials of experimental GBS maternal vaccines, there have been no observed serious adverse events of special interest directly linked to vaccination.
Collapse
Affiliation(s)
- Aline U Bjerkhaug
- Paediatric Research Group, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway; Department of Paediatrics and Adolescence Medicine, University Hospital of North Norway, Tromsø, Norway.
| | - Shouwmika Ramalingham
- Paediatric Research Group, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Robert Mboizi
- Makerere University Johns Hopkins University (MU-JHU) Research Collaboration (MUJHU CARE LTD), Kampala, Uganda
| | - Kirsty Le Doare
- Makerere University Johns Hopkins University (MU-JHU) Research Collaboration (MUJHU CARE LTD), Kampala, Uganda; Centre for Neonatal and Paediatric Infection, Maternal and Neonatal Vaccine Immunology Research Group, St Georgés University of London, United Kingdom
| | - Claus Klingenberg
- Paediatric Research Group, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway; Department of Paediatrics and Adolescence Medicine, University Hospital of North Norway, Tromsø, Norway
| |
Collapse
|
2
|
Ghia C, Rambhad G. Disease burden due to Group B Streptococcus in the Indian population and the need for a vaccine - a narrative review. Ther Adv Infect Dis 2021; 8:20499361211045253. [PMID: 34540226 PMCID: PMC8445532 DOI: 10.1177/20499361211045253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
Streptococcus agalactiae, a Gram-positive bacterium, causes invasive infection known as Group B streptococcal disease (GBS). It is a leading cause of neonatal death and complications prior to delivery. The burden of GBS is unknown in India despite the high incidence of preterm and stillbirths. In this study, we performed a narrative review of the available literature (published in the last 10 years) on the epidemiology of GBS, using PubMed and Google Scholar, to understand its impact in India and evaluate potential strategies to prevent the disease in the high-risk population, that is, neonates. The review showed that the incidence of early- and late-onset GBS in neonates (per 1000 live births) was in the ranges of 0.090-0.68 and 0.0-0.07 respectively. The overall case fatality rate reported in only one study was 0.63. In pregnant women, the prevalence of GBS colonization was 2-62% and its transmission to their newborns varied from 6.7% to 11.1%. The serotype distribution of GBS is unclear, but some studies reported the distribution of types Ia, Ib, II, III, V, VII among pregnant women in India. The associated risk factors for GBS colonization in pregnant women are unclear but a few studies suggest the role of age and multigravida, while the risk factors in neonates include preterm birth, prolonged rupture of membrane (⩾18 h), maternal fever, obstetric complications, and prolonged labor >18 h. Screening of GBS is not a routine practice in India and intrapartum antibiotics prophylaxis is limited to only in risk conditions to prevent neonatal disease transmission. A few studies also suggest that high birth rate, poor detection methods, and financial constraints limit routine GBS screening in a developing country such as India. Hence, maternal vaccination is the most promising strategy to prevent neonatal GBS and Pfizer's hexavalent GBS conjugate vaccine (GBS6) is being developed for GBS neonatal disease.
Collapse
Affiliation(s)
- Canna Ghia
- Pfizer Ltd, The Capital, 1802, 18th Floor, Plot No. C-70, G Block, Bandra Kurla Complex, Bandra (East), Mumbai, Maharashtra 400051, India
| | - Gautam Rambhad
- Pfizer Ltd, The Capital, 1802, 18th Floor, Plot No. C-70, G Block, Bandra Kurla Complex, Bandra (East), Mumbai, 400051, India
| |
Collapse
|
3
|
Lohrmann F, Berg A, Wicker E, Imm A, Krause G, Zürn K, Berner R, Hufnagel M, Lander F. Prevalence of Capsular Serotype, Pilus Island Distribution, and Antibiotic Resistance in Pediatric and Adult Invasive Group B Streptococcus Isolates: Data From a Nationwide Prospective Surveillance Study in Germany. Pediatr Infect Dis J 2021; 40:76-82. [PMID: 33201062 DOI: 10.1097/inf.0000000000002943] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
For neonates, group B Streptococcus is life threatening. Current prevention strategies remain insufficient, especially for cases of late-onset sepsis, where intrapartum antibiotic prophylaxis has demonstrated no benefit. One promising approach is the vaccination of pregnant women, which offers protective immunity via transplacental transmission of neutralizing antibodies. Our nationwide, prospective surveillance study aimed to characterize the prevalence of pilus antigen, capsular polysaccharide serotypes, and antibiotic resistance from invasive GBS infections in neonates and compare these results with those from children and adults in Germany. Our study includes 173 neonatal isolates of a total of 450 reported cases during the study period (incidence: 0.34/1000 live births), in addition to 2 pediatric and 803 adult isolates. The comparison between neonatal and adult isolates reveals age-dependent differences in capsular serotype and pilus type distribution and differences in antibiotic resistance patterns.
Collapse
Affiliation(s)
- Florens Lohrmann
- From the Department of Pediatrics and Adolescent Medicine, University Medical Center, Medical Faculty
- Spemann Graduate School of Biology and Medicine (SGBM), Faculty of Biology
- IMM-PACT Clinician Scientist Program, Faculty of Medicine, Freiburg, Germany
| | - Angela Berg
- From the Department of Pediatrics and Adolescent Medicine, University Medical Center, Medical Faculty
- Department for Gynecology and Obstetrics, DRK Hospital Westend, Berlin, Germany
| | - Esther Wicker
- Department of Anaesthesiology and Operative Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anita Imm
- From the Department of Pediatrics and Adolescent Medicine, University Medical Center, Medical Faculty
| | - Gérard Krause
- Epidemiology Department, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Infectious Disease Epidemiology, TWINCORE, Hannover, Germany
- Translational Infrastructure Epidemiology, German Centre for Infection Research (DZIF), Braunschweig, Germany
| | - Katharina Zürn
- Department of Pediatrics, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Reinhard Berner
- Department of Pediatrics, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Markus Hufnagel
- From the Department of Pediatrics and Adolescent Medicine, University Medical Center, Medical Faculty
| | - Fabian Lander
- Department of Pediatrics, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
4
|
Choi MJ, Noh JY, Jang AY, Cheong HJ, Kim WJ, Song DJ, Cho GJ, Oh MJ, Zhi Y, Seo HS, Song JY. Age-stratified analysis of serotype-specific baseline immunity against group B streptococcus. Hum Vaccin Immunother 2019; 16:1338-1344. [PMID: 31687869 DOI: 10.1080/21645515.2019.1688036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Group B streptococcus (GBS) vaccines are currently under development. Data on the natural immunity in diverse age groups will aid establishing the GBS immunization policy. In this study, thirty serum samples were collected from three age groups (neonates/infants, pregnant women, and the elderly) between August 2016 and July 2017. Serotype-specific opsonophagocytic activity (OPA) was assessed using a GBS multiplex opsonophagocytic killing assay (MOPA) against serotypes Ia, III, and V. The mean OPA titers for serotype Ia of the three age groups were not significantly different (p = .156), but tended to be lower in neonates/infants (mean ± standard deviation, 137 ± 278). For serotype III and V, the mean OPA titer of neonates/infants (338 ± 623 and 161 ± 445, respectively) was significantly lower than that of pregnant women (1377 ± 1167 and 9414 ± 6394) and the elderly (1350 ± 1741 and 3669 ± 5597) (p = .002). In conclusion, the lower levels of OPA titers against all tested serotypes in neonates/infants, despite high maternal titers, indicates that intrapartum GBS vaccinations may be required for efficient placental transfer of serotype-specific GBS antibodies with high avidity.
Collapse
Affiliation(s)
- Min Joo Choi
- Department of Internal Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine , Incheon, Korea
| | - Ji Yun Noh
- Department of Internal Medicine, Korea University College of Medicine , Seoul, Republic of Korea
| | - A-Yeung Jang
- Department of Internal Medicine, Korea University College of Medicine , Seoul, Republic of Korea
| | - Hee Jin Cheong
- Department of Internal Medicine, Korea University College of Medicine , Seoul, Republic of Korea
| | - Woo Joo Kim
- Department of Internal Medicine, Korea University College of Medicine , Seoul, Republic of Korea
| | - Dae Jin Song
- Department of Pediatrics, Korea University College of Medicine , Seoul, Republic of Korea
| | - Geum Joon Cho
- Department of Obstetrics and Gynecology, Korea University College of Medicine , Seoul, Republic of Korea
| | - Min Jeong Oh
- Department of Obstetrics and Gynecology, Korea University College of Medicine , Seoul, Republic of Korea
| | - Yong Zhi
- Biotechnology Division, Korea Atomic Energy Research Institute , Jeongeup, Republic of Korea.,Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology , Daejeon, Republic of Korea
| | - Ho Seong Seo
- Biotechnology Division, Korea Atomic Energy Research Institute , Jeongeup, Republic of Korea.,Department of Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology , Daejeon, Republic of Korea
| | - Joon Young Song
- Department of Internal Medicine, Korea University College of Medicine , Seoul, Republic of Korea
| |
Collapse
|
5
|
Cybulski Z, Urbański B, Grabiec A, Talaga Z, Pawlak M, Wareńczak-Florczak Ż, Roszak A. The incidence of inflammation among patients suffering from cervix cancer with positive beta haemolytic streptococci cultures from genital tract. Rep Pract Oncol Radiother 2019; 24:428-431. [PMID: 31537978 DOI: 10.1016/j.rpor.2019.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 06/06/2019] [Accepted: 07/10/2019] [Indexed: 12/17/2022] Open
Abstract
Aim The main goal of this investigation was to evaluate the influence of positive beta haemolytic streptococci culture from the genital tract on patients receiving radiation therapy who suffer from cervical cancer. The other aim was to observe radiation therapy complications. Background Group B streptococci (GBS), group C streptococci (GCS) and group G streptococci (GGS) have been described as frequent invasive pathogens in elderly patients, often in association with underlying medical conditions including immunodeficiency and cancer. Materials and methods In the years 2006-2015, vaginal swabs from 452 patients were examined. A total of 118 women with positive beta haemolytic streptococci (BHS) groups A, B, C, F, G cultures were analysed, of whom 111 were diagnosed with cervix cancer of IB to IVA degree according to the FIGO 1988 clinical classification. Results Of the 452 patients suffering from cervix cancer 26.1% were positive for A, B, C, F or G group BHS isolated from the genital tract. All of the 114 examined strains were sensitive to beta-lactam antibiotics. The antimicrobials for which resistance was noted were erythromycin, clindamycin, ciprofloxacin and tetracycline. Conclusions Positive cultures of BHS from the genital tract were demonstrated to occur in patients with cervix cancer. Complications were found during radiotherapy in 30 (27%) of these patients, including 20 (18%) patients suffering from clinical symptoms of inflammation. When beta-lactam antibiotics are not recommended because of allergy, sensitivity tests to other drugs are necessary.
Collapse
Affiliation(s)
- Zefiryn Cybulski
- Department of Microbiology, Greater Poland Cancer Centre, Poznań, Poland
| | - Bartosz Urbański
- Department of Radiotherapy and Gynaecological Oncology, Greater Poland Cancer Centre, Poznań, Poland
| | - Alicja Grabiec
- Department of Microbiology, Greater Poland Cancer Centre, Poznań, Poland
| | - Zofia Talaga
- Department of Microbiology, Greater Poland Cancer Centre, Poznań, Poland
| | - Michał Pawlak
- Department of Radiotherapy and Gynaecological Oncology, Greater Poland Cancer Centre, Poznań, Poland
| | - Żaneta Wareńczak-Florczak
- Department of Radiotherapy and Gynaecological Oncology, Greater Poland Cancer Centre, Poznań, Poland
| | - Andrzej Roszak
- Department of Radiotherapy and Gynaecological Oncology, Greater Poland Cancer Centre, Poznań, Poland.,Chair and Department of Electroradiology, University of Medical Sciences, Poznań, Poland
| |
Collapse
|
6
|
Abstract
The surface of the Gram-positive opportunistic pathogen Streptococcus agalactiae, or group B Streptococcus (GBS), harbors several carbohydrate and protein antigens with the potential to be effective vaccines. Capsular polysaccharides of all clinically-relevant GBS serotypes coupled to immunogenic proteins of both GBS and non-GBS origin have undergone extensive testing in animals that led to advanced clinical trials in healthy adult women. In addition, GBS proteins either alone or in combination have been tested in animals; a fusion protein construct has recently advanced to human clinical studies. Given our current understanding of the antigenicity and immunogenicity of the wide array of GBS surface antigens, formulations now exist for the generation of viable vaccines against diseases caused by GBS.
Collapse
|
7
|
Dzanibe S, Madhi SA. Systematic review of the clinical development of group B streptococcus serotype-specific capsular polysaccharide-based vaccines. Expert Rev Vaccines 2018; 17:635-651. [PMID: 29961350 DOI: 10.1080/14760584.2018.1496021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Vaccination against group B Streptococcus (GBS) during pregnancy could provide protection against disease in the mother, fetus, and newborn. Immunity through transplacental acquired antibodies in the newborns could persist through early infancy, reducing the risk of early-onset (<7 days age) and late-onset (7-89 days age) disease. We conducted a systematic review of clinical trials on GBS capsular polysaccharide (CPS) vaccine to assess its safety and immunogenicity in pregnant and nonpregnant adults. AREAS COVERED We searched literature databases PubMed (Medline), Scopus, and the Cochrane library and identified 25 unique records on GBS CPS vaccines with or without conjugant protein. EXPERT COMMENTARY GBS vaccines were well tolerated, with mild local reactogenicity being the main solicited adverse event and no difference in reporting of other serious adverse events compared to placebo recipients. CPS vaccines conjugated to immunogenic proteins induced ≥fourfold increase of serotype-specific antibodies with high longevity (1-2 years); and capable of promoting homotypic GBS opsonophagocytic killing. Feto-maternal transplacental antibody ratio of serotype-specific IgG ranged between 0.49 and 0.81. The clinical relevance of these immunogenicity studies, however, need to be weighed against a correlate of protection against invasive GBS disease in infants, which is yet to be established using a universally accepted standardized assay.
Collapse
Affiliation(s)
- Sonwabile Dzanibe
- a Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences , University of the Witwatersrand , Johannesburg , South Africa.,b Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences , University of the Witwatersrand , Johannesburg , South Africa.,c Division of Immunology , University of Cape Town , Cape Town , South Africa
| | - Shabir A Madhi
- a Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty of Health Sciences , University of the Witwatersrand , Johannesburg , South Africa.,b Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty of Health Sciences , University of the Witwatersrand , Johannesburg , South Africa
| |
Collapse
|
8
|
Peña-Garcia JI, Shaikh S, Lacasse A. Invasive Group B streptococcus: multiloculated perinephric abscesses treated with percutaneous drainage. J Community Hosp Intern Med Perspect 2018; 8:76-79. [PMID: 29686793 PMCID: PMC5906762 DOI: 10.1080/20009666.2018.1433431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/22/2018] [Indexed: 11/07/2022] Open
Abstract
Group B streptococcus infections (GBSI) are commonly associated with neonates and pregnant women, but may also affect nonpregnant adults. Among its spectrum of manifestations, perinephric abscess (PA) is exceedingly rare. Comorbid conditions such as diabetes mellitus (DM) and immunosuppression increase the risk of GBSI. We describe a 61-year-old Vietnamese man with compensated alcoholic cirrhosis, who presented with acute encephalopathy following subacute, progressive abdominal pain. He was afebrile and hemodynamically stable. Laboratory data were remarkable for leukocytosis, thrombocytopenia, azotemia, and pyuria. He was found to have two right-sided PA measuring 15 × 10 × 11 cm and 4.6 × 2.7 × 7.8 cm, requiring interval placement of multiple percutaneous drains. Culture from abscesses revealed beta-hemolytic Group B streptococcus (GBS). His course was complicated by contiguous spread to abdominal wall and paraspinal musculature, as well as a new diagnosis of type 2 DM. Along with drainage, a prolonged course of intravenous antimicrobial treatment led to abscess resolution. Given the rising number of unusual clinical presentations of GBSI, this bacteria should be considered as a part of the microbiological differential diagnosis of PA, especially in conditions leading to immunosuppression.
Collapse
Affiliation(s)
- J. Isaac Peña-Garcia
- Department of Internal Medicine, SSM St. Mary’s Hospital - St. Louis, St. Louis, MO, USA
| | - Sana Shaikh
- Department of Internal Medicine, SSM St. Mary’s Hospital - St. Louis, St. Louis, MO, USA
| | - Alexandre Lacasse
- Department of Internal Medicine, SSM St. Mary’s Hospital - St. Louis, St. Louis, MO, USA
| |
Collapse
|
9
|
Edwards MS, Rench MA, Rinaudo CD, Fabbrini M, Tuscano G, Buffi G, Bartolini E, Bonacci S, Baker CJ, Margarit I. Immune Responses to Invasive Group B Streptococcal Disease in Adults. Emerg Infect Dis 2018; 22:1877-1883. [PMID: 27767008 PMCID: PMC5088039 DOI: 10.3201/eid2211.160914] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Antibodies to capsular polysaccharides and pilus proteins develop in recovering adults. Immunization of nonpregnant adults could help prevent invasive group B Streptococcus (GBS) infections, but adult immune responses have not been investigated. We defined capsular polysaccharide (CPS) and pilus island (PI) surface antigen distribution and expression and immune responses to GBS infection in nonpregnant adults. Prospective surveillance from 7 hospitals in Houston, Texas, USA, identified 102 adults with GBS bacteremia; 43% had skin/soft tissue infection, 16% bacteremia without focus, and 12% osteomyelitis. CPS-specific IgG was determined by ELISA and pilus-specific IgG by multiplex immunoassay. CPS types were Ia (24.5%), Ib (12.7%), II (9.8%), III (16.7%), IV (13.7%), and V (12.7%); 9.8% were nontypeable by serologic methods. Pili, expressed by 89%, were most often PI-2a. CPS and pilus-specific IgG increased during convalescence among patients with strains expressing CPS or PI. All GBS expressed CPS or PI; 79% expressed both. Increased antibodies to CPS and PI during recovery suggests that GBS bacteremia in adults is potentially vaccine preventable.
Collapse
|
10
|
Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract. Microbiol Spectr 2017; 4. [PMID: 27227294 DOI: 10.1128/microbiolspec.uti-0012-2012] [Citation(s) in RCA: 191] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Gram-positive bacteria are a common cause of urinary-tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI.
Collapse
|
11
|
Streptococcus agalactiae Toxic Shock Syndrome: New Agent, New Challenges. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2017. [DOI: 10.1097/ipc.0000000000000429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
12
|
Santos-Sierra S, Golenbock DT, Henneke P. Toll-like receptor-dependent discrimination of streptococci. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120050601] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Streptococcus pneumoniae and Streptococcus agalactiae cause distinct infectious diseases in small children. Similarly, these bacteria elicit very different host-cell responses in vitro. Inactivated S. agalactiae by far exceeds S. pneumoniae in the activation of inflammatory cytokines and upstream signaling intermediates such as the MAP kinase JNK. The inflammatory response to both Streptococcus spp. is mediated by MyD88, an essential adapter protein of Toll-like receptors (TLRs), although the specific TLRs that are involved have not been fully resolved. Furthermore, during logarithmic growth, S. pneumoniae releases pneumolysin that interacts with TLR4 whereas S. agalactiae releases diacylated molecules that interact with TLR2/6. Interaction of these soluble bacterial products with their cognate TLRs is critical for limiting bacterial dissemination and and systemic inflammation in mice. This might be due, in part, to TLR-mediated apoptosis induced by these factors. In conclusion related streptococcal species induce specific events in TLR-mediated signal transduction. Comparative analysis of the host-cell response to these bacteria reveals molecules such as JNK as valuable targets for adjunctive sepsis therapy.
Collapse
Affiliation(s)
| | - Douglas T. Golenbock
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Philipp Henneke
- Division of Infectious Diseases, Children's Hospital, Freiburg, Germany, philipp.henneke@ uniklinik-freiburg.de
| |
Collapse
|
13
|
Molecular Characteristics of Group B Streptococci Isolated from Adults with Invasive Infections in Japan. J Clin Microbiol 2016; 54:2695-2700. [PMID: 27558182 DOI: 10.1128/jcm.01183-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/15/2016] [Indexed: 01/18/2023] Open
Abstract
Streptococcus agalactiae (group B streptococcus) isolates (n = 443) obtained from Japanese adults with invasive infections between April 2010 and March 2013 were analyzed for capsular serotype, multilocus sequence type (ST), antibiotic susceptibility, and resistance genes. Among these cases, bacteremia without primary focus was the most common variety of infection (49.9%), followed by cellulitis (12.9%) and pneumonia (9.0%). Concerning patient age (18 to 59, 60 to 69, 70 to 79, 80 to 89, and 90 years old or older), the incidence of pneumonia increased in patients in their 70s and 80s (P < 0.001), while younger patients (18 to 59 and 60 to 69 years old) were more likely to have abscesses (P < 0.05). The mortality rate was 10.2% for all ages. The most common capsular serotype was Ib (39.5%), followed by V (16.0%), III (13.8%), VI (9.5%), and Ia (8.6%). The main ST of serotype Ib strains was ST10, which belonged to clonal complex 10 (88.0%). The predominant clonal complexes of serotypes V and III, respectively, were 1 (78.9%) and 19 (75.4%). Among these isolates, 9 strains (2.0%) were identified as group B streptococci with reduced penicillin susceptibility, reflecting amino acid substitutions in penicillin-binding protein 2X (PBP2X). In addition, 19.2% of all strains possessed mef(A/E), erm(A), or erm(B) genes, which mediate macrolide resistance, while 40.2% of strains were resistant to quinolones resulting from amino acid substitutions in GyrA and ParC. Our data argue strongly for the continuous surveillance of microbial characteristics and judicious antibiotic use in clinical practice.
Collapse
|
14
|
Kenchington AL, Lamont RF. Group B streptococcal immunisation of pregnant women for the prevention of early and late onset Group B streptococcal infection of the neonate as well as adult disease. Expert Rev Vaccines 2016; 16:15-25. [PMID: 27385362 DOI: 10.1080/14760584.2016.1209113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Early onset neonatal Group B streptococcal disease is preventable. Intrapartum antibiotic prophylaxis has resulted in a significant reduction in neonatal mortality and morbidity. National guidelines for the selection of women eligible for intrapartum antibiotic prophylaxis, whether screening-based or risk-based, differ according to the local burden of disease. Despite the introduction of intrapartum antibiotic prophylaxis, there remains a significant burden of disease, which can be resolved by better adherence to guidelines, rapid identification of maternal colonization or in the future, vaccination. Areas covered: The introduction of a vaccine to women in the third trimester is likely to further reduce the burden of disease and provide benefits beyond the prevention of early neonatal disease, including meningitis and disability following late onset disease. Development of specific polyvalent vaccines continues, but testing has challenges and may require surrogate markers or molecular-based techniques to manipulate antigenicity and immunogenicity. Expert commentary: Group B streptococcal vaccination using conjugated polyvalent vaccines against the major disease causing serotypes of Group B streptococcus, either alone, or in combination with a policy of intrapartum antibiotic prophylaxis, may decrease the burden of Group B streptococcus beyond that achieved by current use of intrapartum antibiotic prophylaxis alone.
Collapse
Affiliation(s)
| | - Ronald F Lamont
- b Department of Gynaecology and Obstetrics, Clinical Institute , University of Southern Denmark, Odense University Hospital , Odense , Denmark.,c Division of Surgery , University College London, Northwick Park Institute of Medical Research Campus , London , UK
| |
Collapse
|
15
|
Nuccitelli A, Rinaudo CD, Maione D. Group B Streptococcus vaccine: state of the art. THERAPEUTIC ADVANCES IN VACCINES 2015; 3:76-90. [PMID: 26288735 DOI: 10.1177/2051013615579869] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Group B Streptococcus (GBS) is cause of neonatal invasive diseases as well as of severe infections in the elderly and immune-compromised patients. Despite significant advances in the prevention and treatment of neonatal disease, sepsis and meningitis caused by GBS still represent a significant public health care concern globally and additional prevention and therapeutic strategies against infection are highly desirable. The introduction of national recommended guidelines in several countries to screen pregnant women for GBS carriage and the use of antibiotics during delivery significantly reduced disease occurring within the first hours of life (early-onset disease), but it has had no effect on the late-onset diseases occurring after the first week and is not feasible in most countries. Availability of an effective vaccine against GBS would provide an effective means of controlling GBS disease. This review provides an overview of the burden of invasive disease caused by GBS in infants and adults, and highlights the strategies for the development of an effective vaccine against GBS infections.
Collapse
Affiliation(s)
| | | | - Domenico Maione
- Novartis Vaccines and Diagnostics, via Fiorentina 1, 53100 Siena, Italy
| |
Collapse
|
16
|
Abstract
Streptococcus agalactiae (Group B streptococcus) is an important cause of disease in infants, pregnant women, the elderly and in immunosuppressed adults. An effective vaccine is likely to prevent the majority of infant disease (both early and late onset), as well as Group B streptococcus-related stillbirths and prematurity, to avoid the current real and theoretical limitations of intrapartum antibiotic prophylaxis, and to be cost effective. The optimal time to administer such a vaccine would be in the third trimester of pregnancy. The main limitations on the production of a Group B streptococcus vaccine are not technical or scientific, but regulatory and legal. A number of candidates including capsular conjugate vaccines using traditional carrier proteins such as tetanus toxoid and mutant diphtheria toxin CRM197, as well as Group B streptococcus-specific proteins such as C5a peptidase, protein vaccines using one or more Group B streptococcus surface proteins and mucosal vaccines, have the potential to be successful vaccines. The capsular conjugate vaccines using tetanus and CRM197 carrier proteins are the most advanced candidates, having already completed Phase II human studies including use in the target population of pregnant women (tetanus toxoid conjugate), however, no definitive protein conjugates have yet been trialed. However, unless the regulatory environment is changed specifically to allow the development of a Group B streptococcus vaccine, it is unlikely that one will ever reach the market.
Collapse
Affiliation(s)
- Paul T Heath
- Department of Child Health and Vaccine Institute, St George's Hospital Medical School, London, UK.
| | | |
Collapse
|
17
|
|
18
|
|
19
|
Cole JN, Henningham A, Gillen CM, Ramachandran V, Walker MJ. Human pathogenic streptococcal proteomics and vaccine development. Proteomics Clin Appl 2012; 2:387-410. [PMID: 21136841 DOI: 10.1002/prca.200780048] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Gram-positive streptococci are non-motile, chain-forming bacteria commonly found in the normal oral and bowel flora of warm-blooded animals. Over the past decade, a proteomic approach combining 2-DE and MS has been used to systematically map the cellular, surface-associated and secreted proteins of human pathogenic streptococcal species. The public availability of complete streptococcal genomic sequences and the amalgamation of proteomic, genomic and bioinformatic technologies have recently facilitated the identification of novel streptococcal vaccine candidate antigens and therapeutic agents. The objective of this review is to examine the constituents of the streptococcal cell wall and secreted proteome, the mechanisms of transport of surface and secreted proteins, and describe the current methodologies employed for the identification of novel surface-displayed proteins and potential vaccine antigens.
Collapse
Affiliation(s)
- Jason N Cole
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | | | | | | | | |
Collapse
|
20
|
Edwards MS, Lane HJ, Hillier SL, Rench MA, Baker CJ. Persistence of functional antibodies to group B streptococcal capsular polysaccharides following immunization with glycoconjugate vaccines. Vaccine 2012; 30:4123-6. [PMID: 22537994 DOI: 10.1016/j.vaccine.2012.04.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 04/04/2012] [Accepted: 04/12/2012] [Indexed: 11/30/2022]
Abstract
The duration of functional activity of group B streptococcal (GBS) glycoconjugate vaccine-induced capsular polysaccharide-specific (CPS) IgG was evaluated among healthy adult responders. Opsonophagocytic activity declined significantly from a 4-week post-immunization peak, but substantial functional activity, exceeding 1 log(10) reduction in GBS cfu/mL, was retained at 18 months to 2 years post-immunization for each GBS type assessed. The persistence of functional antibody activity when GBS CPS-specific IgG concentrations decline, although remaining significantly higher than pre-immunization levels, suggests that long-term protection may be expected from candidate GBS glycoconjugates administered to this population.
Collapse
Affiliation(s)
- Morven S Edwards
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
| | | | | | | | | |
Collapse
|
21
|
Progress in the development of effective vaccines to prevent selected gram-positive bacterial infections. Am J Med Sci 2010; 340:218-25. [PMID: 20697258 DOI: 10.1097/maj.0b013e3181e939ab] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Infections caused by virulent Gram-positive bacteria, such as Staphylococcus aureus, group B streptococci and group A streptococci, remain significant causes of morbidity and mortality despite progress in antimicrobial therapy. Despite significant advances in the understanding of the pathogenesis of infection caused by these organisms, there are only limited strategies to prevent infection. In this article, we review efforts to develop safe and effective vaccines that would prevent infections caused by these 3 pathogens.
Collapse
|
22
|
High KP, D'Aquila RT, Fuldner RA, Gerding DN, Halter JB, Haynes L, Hazzard WR, Jackson LA, Janoff E, Levin MJ, Nayfield SG, Nichol KL, Prabhudas M, Talbot HK, Clayton CP, Henderson R, Scott CM, Tarver ED, Woolard NF, Schmader KE. Workshop on immunizations in older adults: identifying future research agendas. J Am Geriatr Soc 2010; 58:765-76. [PMID: 20398161 DOI: 10.1111/j.1532-5415.2010.02772.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Goals for immunization in older adults may differ from those in young adults and children, in whom complete prevention of disease is the objective. Often, reduced hospitalization and death but also averting exacerbation of underlying chronic illness, functional decline, and frailty are important goals in the older age group. Because of the effect of age on dendritic cell function, T cell-mediated immune suppression, reduced proliferative capacity of T cells, and other immune responses, the efficacy of vaccines often wanes with advanced age. This article summarizes the discussion and proceedings of a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the American Geriatrics Society, the National Institute on Aging, and the National Institute of Allergy and Infectious Diseases. Leading researchers and clinicians in the fields of immunology, epidemiology, infectious diseases, geriatrics, and gerontology reviewed the current status of vaccines in older adults, identified knowledge gaps, and suggest priority areas for future research. The goal of the workshop was to identify what is known about immunizations (efficacy, effect, and current schedule) in older adults and to recommend priorities for future research. Investigation in the areas identified has the potential to enhance understanding of the immune process in aging individuals, inform vaccine development, and lead to more-effective strategies to reduce the risk of vaccine-preventable illness in older adults.
Collapse
Affiliation(s)
- Kevin P High
- Division of Infectious Diseases, Department of Internal Medicine, School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Sendi P, Johansson L, Norrby-Teglund A. Invasive Group B Streptococcal Disease in Non-pregnant Adults. Infection 2008; 36:100-11. [DOI: 10.1007/s15010-007-7251-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 09/19/2007] [Indexed: 01/22/2023]
|
24
|
|
25
|
Carlin AF, Lewis AL, Varki A, Nizet V. Group B streptococcal capsular sialic acids interact with siglecs (immunoglobulin-like lectins) on human leukocytes. J Bacteriol 2006; 189:1231-7. [PMID: 16997964 PMCID: PMC1797352 DOI: 10.1128/jb.01155-06] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group B Streptococcus (GBS) is classified into nine serotypes that vary in capsular polysaccharide (CPS) architecture but share in common the presence of a terminal sialic acid (Sia) residue. This position and linkage of GBS Sia closely resembles that of cell surface glycans found abundantly on human cells. CD33-related Siglecs (CD33rSiglecs) are a family of Sia-binding lectins expressed on host leukocytes that engage host Sia-capped glycans and send signals that dampen inflammatory gene activation. We hypothesized that GBS evolved to display CPS Sia as a form of molecular mimicry limiting the activation of an effective innate immune response. In this study, we applied a panel of immunologic and cell-based assays to demonstrate that GBS of several serotypes interacts in a Sia- and serotype-specific manner with certain human CD33rSiglecs, including hSiglec-9 and hSiglec-5 expressed on neutrophils and monocytes. Modification of GBS CPS Sia by O acetylation has recently been recognized, and we further show that the degree of O acetylation can markedly affect the interaction between GBS and hSiglec-5, -7, and -9. Thus, production of Sia-capped bacterial polysaccharide capsules that mimic human cell surface glycans in order to engage CD33rSiglecs may be an example of a previously unrecognized bacterial mechanism of leukocyte manipulation.
Collapse
Affiliation(s)
- Aaron F Carlin
- Department of Pediatrics, Division of Pharmacology and Drug Discovery, University of California, San Diego School of Medicine, Cellular and Molecular Medicine East, La Jolla, CA 92093-0687, USA
| | | | | | | |
Collapse
|
26
|
Baker CJ, Rench MA, Paoletti LC, Edwards MS. Dose-response to type V group B streptococcal polysaccharide-tetanus toxoid conjugate vaccine in healthy adults. Vaccine 2006; 25:55-63. [PMID: 16919857 DOI: 10.1016/j.vaccine.2006.07.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 06/28/2006] [Accepted: 07/14/2006] [Indexed: 11/16/2022]
Abstract
A phase 1, dose-escalating trial was conducted in healthy adults to evaluate immunogenicity and reactogenicity of a type V group B streptococcal (GBS) capsular polysaccharide (CPS)-tetanus toxoid (TT) conjugate vaccine. Participants received one dose of unconjugated V CPS (37 microg), V-TT (2.4 microg CPS/1.1 microg TT), V-TT (9.6 microg CPS/4.3 microg TT) or V-TT (38.5 microg CPS/17.0 microg TT). Each vaccine and all doses of V-TT were well-tolerated. V CPS-specific antibodies reached a peak 4-8 weeks after immunization and were significantly higher through 52 weeks post-immunization in recipients of V-TT at each dose than in uncoupled CPS vaccinees. V-TT vaccine-induced antibodies promoted opsonophagocytic killing of type V GBS and avidity maturation of V CPS-specific IgG.
Collapse
Affiliation(s)
- Carol J Baker
- Section of Infectious Diseases, Department of Pediatrics, Room 302A, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States.
| | | | | | | |
Collapse
|
27
|
Henneke P, Berner R. Interaction of neonatal phagocytes with group B streptococcus: recognition and response. Infect Immun 2006; 74:3085-95. [PMID: 16714536 PMCID: PMC1479263 DOI: 10.1128/iai.01551-05] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Philipp Henneke
- Zentrum für Kinderheilkunde und Jugendmedizin, Albert-Ludwigs Universität Freiburg, Mathildenstr. 1, 79106 Freiburg, Germany.
| | | |
Collapse
|
28
|
Abstract
PURPOSE OF REVIEW The advent of human Toll-like receptors has revolutionized our understanding of innate immunity. This review summarizes recent discoveries about the role of Toll-like receptors and innate immunity in neonatal sepsis with a particular emphasis on the paradigmatic organism S. agalactiae. RECENT FINDINGS S. agalactiae stimulates phagocytes to excessive formation of inflammatory cytokines such as tumor necrosis factor, and Toll-like receptors are essential for this response both in vivo and in vitro. On the molecular level, distinct signaling pathways are engaged by released S. agalactiae toxins such as lipoteichoic acid (Toll-like receptor-2 dependent) and cell-bound toxins (Toll-like receptor-2 independent). In contrast, complement receptors and Fc receptors, but not Toll-like receptors, are directly involved in phagocytosis and therefore elimination of S. agalactiae. Notably, neonatal phagocytes potently activate cytokines in response to S. agalactiae but are deficient in S. agalactiae uptake and killing. Interference with the Toll-like receptor-dependent mitogen activated protein kinase cJun N-terminal Kinase improves outcome in a neonatal model of S. agalactiae sepsis by inhibiting cytokine formation but preserving clearance of S. agalactiae. SUMMARY Recent progress in the understanding of S. agalactiae recognition and phagocytic signaling in neonatal sepsis suggests intermediates in the Toll-like receptor pathways as valuable targets for adjunctive sepsis therapy.
Collapse
Affiliation(s)
- Sybille Kenzel
- Zentrum für Kinderheilkunde und Jugendmedizin, Albert-Ludwigs Universität Freiburg, Freiburg, Germany
| | | |
Collapse
|
29
|
Edwards MS, Baker CJ. Group B streptococcal infections in elderly adults. Clin Infect Dis 2005; 41:839-47. [PMID: 16107984 DOI: 10.1086/432804] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Accepted: 05/30/2005] [Indexed: 11/03/2022] Open
Abstract
Elderly adults account for >40% of persons with invasive group B streptococcal (GBS) disease and for >50% of GBS-associated deaths in the United States. The prevalence of colonization among healthy elderly adults (approximately 25%) is similar to that among women of childbearing age. Delineating contributions of comorbid conditions, altered integrity of anatomical barriers, and abnormalities in immune responses caused by immune senescence to pathogenesis require further investigation. Delayed clinical recognition of illness may contribute to poor outcome. Skin and soft-tissue infections and bacteremia with no identified focus are common manifestations of infection in elderly adults and younger nonpregnant adults. Urinary tract infection and pneumonia are presentations more often encountered in elderly persons than in younger adults. The safety and immunogenicity of GBS serotype V-tetanus toxoid conjugate vaccine in healthy elderly persons suggest the potential for vaccination as an approach to prevention of invasive GBS infections in elderly persons.
Collapse
Affiliation(s)
- Morven S Edwards
- Section of Infectious Disease, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
| | | |
Collapse
|
30
|
Kumar V, Ganguly NK, Joshi K, Mittal R, Harjai K, Chhibber S, Sharma S. Protective efficacy and immunogenicity of Escherichia coli K13 diphtheria toxoid conjugate against experimental ascending pyelonephritis. Med Microbiol Immunol 2005; 194:211-7. [PMID: 15909203 DOI: 10.1007/s00430-005-0241-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Indexed: 10/25/2022]
Abstract
In the present study, protective efficacy of Escherichia coli capsular antigen, K13, was evaluated in a mouse model of pyelonephritis. Unconjugated capsular polysaccharide failed to provide any protection. However, coupling of K13 to diphtheria toxoid (DT) enhanced its immunogenicity and led to significant production of anticapsular antibodies in mice. Immunization of animals with K13-DT conjugate also caused significant improvement in cell-mediated immune response as indicated by an increase in lymphoblastogenic response and in the CD4+/CD8+ cell ratio of splenic lymphocytes. Significant decrease in bacterial load and renal severity scores were observed in K13-DT immunized animals. Suitability of K13-DT conjugate as an effective vaccine candidate against urinary tract infections caused by E. coli has been discussed.
Collapse
Affiliation(s)
- Varinder Kumar
- Department of Microbiology, Panjab University, Basic Medical Sciences Building, Sector 14, Chandigarh, 160014, India
| | | | | | | | | | | | | |
Collapse
|