1
|
Khan K. Neurodevelopmental impairment associated with neonatal invasive group B Streptococcus disease: Are animal models on track in understanding the mechanisms at play? Brain Behav Immun Health 2024; 40:100831. [PMID: 39144833 PMCID: PMC11320442 DOI: 10.1016/j.bbih.2024.100831] [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: 11/28/2023] [Revised: 06/23/2024] [Accepted: 07/20/2024] [Indexed: 08/16/2024] Open
Abstract
Invasive Group B Streptococcus (iGBS) disease is a prominent cause of neurodevelopmental impairment (NDI) in neonates. While the clinical manifestation of iGBS disease in neonates may include pneumonia and meningitis, generalised sepsis without focus is the most frequent manifestation of iGBS disease in neonates. Though recent human based studies highlighted meningitis as an important manifestation in infants with NDI following iGBS disease, they also noted that ∼18% of neonates present with NDI following iGBS related sepsis. Thus, it is important to not only understand the long-term pathophysiological changes associated with NDI in iGBS meningitis survivors, but so too for iGBS sepsis survivors. Since the late 1970's animal models have been used to unravel the pathophysiology of neonatal iGBS disease. These studies have inoculated neonatal or pregnant animals with GBS via various peripheral or central routes. The greatest challenge with using animal models to study NDI associated with neonatal iGBS disease, is effectively mimicking the clinical presentations of pneumonia, sepsis, and meningitis, while inducing relevant pathophysiological changes and ensuring animals survival, so as to test the neurodevelopment of the animals. This review aims to evaluate the validity of neonatal rodent models, specifically in studying NDI associated with neonatal iGBS disease and explore possible future avenues of research in addressing long-term NDI in the clinical setting.
Collapse
Affiliation(s)
- Khaalid Khan
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| |
Collapse
|
2
|
Pellegrini A, Motta C, Bellan Menegussi E, Pierangelini A, Viglio S, Coppolino F, Beninati C, De Filippis V, Barbieri G, Pietrocola G. The serine-rich repeat glycoprotein Srr2 mediates Streptococcus agalactiae interaction with host fibronectin. BMC Microbiol 2024; 24:221. [PMID: 38909237 PMCID: PMC11193222 DOI: 10.1186/s12866-024-03374-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 06/17/2024] [Indexed: 06/24/2024] Open
Abstract
BACKGROUND Group B Streptococcus (GBS) is a commensal of healthy adults and an important pathogen in newborns, the elderly and immunocompromised individuals. GBS displays several virulence factors that promote colonisation and host infection, including the ST-17 strain-specific adhesin Srr2, previously characterised for its binding to fibrinogen. Another common target for bacterial adhesins and for host colonization is fibronectin, a multi-domain glycoprotein found ubiquitously in body fluids, in the extracellular matrix and on the surface of cells. RESULTS In this study, fibronectin was identified as a novel ligand for the Srr2 adhesin of GBS. A derivative of the ST-17 strain BM110 overexpressing the srr2 gene showed an increased ability to bind fibrinogen and fibronectin, compared to the isogenic wild-type strain. Conversely, the deletion of srr2 impaired bacterial adhesion to both ligands. ELISA assays and surface plasmon resonance studies using the recombinant binding region (BR) form of Srr2 confirmed a direct interaction with fibronectin with an estimated Kd of 92 nM. Srr2-BR variants defective in fibrinogen binding also exhibited no interaction with fibronectin, suggesting that Srr2 binds this ligand through the dock-lock-latch mechanism, previously described for fibrinogen binding. The fibronectin site responsible for recombinant Srr2-BR binding was identified and localised in the central cell-binding domain of the protein. Finally, in the presence of fibronectin, the ability of a Δsrr2 mutant to adhere to human cervico-vaginal epithelial cells was significantly lower than that of the wild-type strain. CONCLUSION By combining genetic and biochemical approaches, we demonstrate a new role for Srr2, namely interacting with fibronectin. We characterised the molecular mechanism of this interaction and demonstrated that it plays a role in promoting the adhesion of GBS to human cervico-vaginal epithelial cells, further substantiating the role of Srr2 as a factor responsible for the hypervirulence of GBS ST-17 strains. The discovery of the previously undescribed interaction between Srr2 and fibronectin establishes this adhesin as a key factor for GBS colonisation of host tissues.
Collapse
Affiliation(s)
| | - Chiara Motta
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | | | - Andrea Pierangelini
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Simona Viglio
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Francesco Coppolino
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Concetta Beninati
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Vincenzo De Filippis
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Giulia Barbieri
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
| | | |
Collapse
|
3
|
Rashid MH, Habib T, Bukhari SNY, Riaz F, Kolman-Taddeo D. Group B Streptococcus Persistently Colonizing the Adenosquamous Carcinoma of the Lung: A Blessing in Disguise? Cureus 2024; 16:e57377. [PMID: 38694652 PMCID: PMC11061868 DOI: 10.7759/cureus.57377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2024] [Indexed: 05/04/2024] Open
Abstract
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.
Collapse
Affiliation(s)
| | - Tehmina Habib
- Internal Medicine, Capital Health Regional Medical Center, Trenton, USA
| | | | - Faiqa Riaz
- Internal Medicine, Sir Syed Medical College, Karachi, PAK
| | - Diana Kolman-Taddeo
- Interventional Pulmonology, Capital Health Regional Medical Center, Trenton, USA
| |
Collapse
|
4
|
Zang X, Dang G, Cai Z, Shao M, Tang Y, Cao J, Cui Z, Liu S. Extracellular DNase MAP3916c attacks the neutrophil extracellular traps and is needed for Mycobacterium avium subsp. paratuberculosis virulence. Vet Microbiol 2022; 273:109529. [PMID: 35944391 DOI: 10.1016/j.vetmic.2022.109529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/29/2022] [Accepted: 08/02/2022] [Indexed: 11/27/2022]
Abstract
Extracellular DNases/nucleases are important virulence factors in many bacteria. However, no DNase/nucleases have been reported in Mycobacterium avium subsp. paratuberculosis (MAP), which is a pathogen of paratuberculosis. Genome analyses of MAP K-10 revealed that the map3916c gene putatively encodes a nuclease. In this study, we show that MAP3916c is an extracellular nonspecific DNase requiring a divalent cation, especially Mg2+. The optimum DNase activity of MAP3916c was exhibited at 41 °C and pH 9.0. Site-directed mutagenesis studies indicated that 125-Histidine is necessary for MAP3916c DNase activity. In addition, MAP3916c DNase could destroy the neutrophil extracellular traps (NETs) induced by Phorbol 12-myristate 13-acetate in vitro and degrade the NETs induced by MAP K-10 upon infection. Furthermore, MAP3916c DNase promoted the colonization of MAP K-10, induced the formation of granulomas in the liver and small intestine and promoted the release of IL-1β, IL-6 and TNF-α inflammatory cytokines during the infection of mice. These results indicated that MAP3916c is relevant to NETs escape and the pathogenicity of MAP. It also provides a basis for further study of the function of nuclease activity on the MAP immune evasion.
Collapse
Affiliation(s)
- Xinxin Zang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Guanghui Dang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Zhuming Cai
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Mingzhu Shao
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Yangyang Tang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China; College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Jun Cao
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Ziyin Cui
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin 150069, China.
| |
Collapse
|
5
|
Bai Q, Ma J, Zhang Z, Zhong X, Pan Z, Zhu Y, Zhang Y, Wu Z, Liu G, Yao H. YSIRK-G/S-directed translocation is required for Streptococcus suis to deliver diverse cell wall anchoring effectors contributing to bacterial pathogenicity. Virulence 2021; 11:1539-1556. [PMID: 33138686 PMCID: PMC7644249 DOI: 10.1080/21505594.2020.1838740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Streptococcus suis serotype 2 (SS2) is a significant zoonotic pathogen that is responsible for various swine diseases, even causing cytokine storms of Streptococcal toxic shock-like syndromes amongst human. Cell wall anchoring proteins with a C-terminal LPxTG are considered to play vital roles during SS2 infection; however, their exporting mechanism across cytoplasmic membranes has remained vague. This study found that YSIRK-G/S was involved in the exportation of LPxTG-anchoring virulence factors MRP and SspA in virulent SS2 strain ZY05719. The whole-genome analysis indicated that diverse LPxTG proteins fused with an N-terminal YSIRK-G/S motif are encoded in strain ZY05719. Two novel LPxTG proteins SspB and YzpA were verified to be exported via a putative transport system that was dependent on the YSIRK-G/S directed translocation, and portrayed vital functions during the infection of SS2 strain ZY05719. Instead of exhibiting an inactivation of C5a peptidase in SspB, another LPxTG protein with an N-terminal YSIRK-G/S motif from Streptococcus agalactiae was depicted to cleave the C5a component of the host complement. The consequent domain-architecture retrieval determined more than 10,000 SspB/YzpA like proteins that are extensively distributed in the Gram-positive bacteria, and most of them harbor diverse glycosyl hydrolase or peptidase domains within their middle regions, thus presenting their capability to interact with host cells. The said findings provide compelling evidence that LPxTG proteins with an N-terminal YSIRK-G/S motif are polymorphic effectors secreted by Gram-positive bacteria, which can be further proposed to define as cell wall anchoring effectors in a new subset.
Collapse
Affiliation(s)
- Qiankun Bai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Jiale Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Ze Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Xiaojun Zhong
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Zihao Pan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Yinchu Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Yue Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Guangjin Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| |
Collapse
|
6
|
Nabavinia M, Khalili MB, Sadeh M, Eslami G, Vakili M, Azartoos N, Mojibiyan M. Distribution of Pilus island and antibiotic resistance genes in Streptococcus agalactiae obtained from vagina of pregnant women in Yazd, Iran. IRANIAN JOURNAL OF MICROBIOLOGY 2020; 12:411-416. [PMID: 33603995 PMCID: PMC7867704 DOI: 10.18502/ijm.v12i5.4601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Background and Objectives: Due to the important role of Streptococcus agalactiae, Group B streptococci (GBS), in production of invasive disease in neonates, investigation regarding the pathogenicity and antibiotic resistance factors is necessary in selecting the appropriate therapeutic agents. Beside capsule, the pilus has been currently recognized as an important factor in enhancing the pathogenicity of GBS. Resistance of GBS to selected antibiotics is noticeably increasing which is mainly due to the anomalous use of these drugs for treatment. The aim of this study was to determine the prevalence of pili genes followed by antibiotic susceptibility of GBS, previously serotyped, isolated from pregnant women in the city of Yazd, Iran. Materials and Methods: Fifty seven GBS from pregnant women were subjected to multiplex PCR for determination of PI-1, PI-2a and PI-2b pilus-islands and simultaneously, the phenotype of antibiotic resistance to penicillin, tetracycline, erythromycin, clindamycin, gentamycin and levofloxacin was determined. Antibiotic resistance genes (ermA, ermB, mefA, tetM, int-Tn) were further diagnosed using PCR and multiplex PCR. Results: PI-1+PI-2a with 71.9%; followed by PI-2a (21.1%) and PI-2b (7%) were observed. PI-1+PI-2a in serotype III was (73.2%), serotype II, Ia, Ib and V were 12.2%, 9.8%, 2.4% and 2.4% respectively. GBS penicillin sensitive was 89.5% and 96.5% resistance to tetracycline. The frequency of resistance genes were as follows: tetM (93%), ermA (33.3%), ermB (8.8%), int-Tn (80.7%) and mefA (0). Conclusion: Majority of GBS contained PI-1+PI-2a. Hence presence of this pilus stabilizes the colonization, therefore designing a program for diagnosing and treatment of infected pregnant women seems to be necessary.
Collapse
Affiliation(s)
- Mahdieh Nabavinia
- Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Bagher Khalili
- Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Maryam Sadeh
- Department of Laboratory Sciences, Faculty of Paramedical Sciences, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Gilda Eslami
- Department of Parasitology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mahmood Vakili
- Department of Public Medicine, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Nastaran Azartoos
- Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mahdiye Mojibiyan
- Department of Obstetrics and Gynecology, Mojibiyan Hospital, Yazd, Iran
| |
Collapse
|
7
|
Silvestre I, Borrego MJ, Jordão L. Biofilm formation by ST17 and ST19 strains of Streptococcus agalactiae. Res Microbiol 2020; 171:311-318. [PMID: 32896574 DOI: 10.1016/j.resmic.2020.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 11/26/2022]
Abstract
Bacterial biofilms are an important virulence factor with a vital role in evasion from the host immune system, colonization and infection. The aim of the present study was to evaluate in vitro the effects of three environmental factors (H+, glucose and human plasma) in biofilm formation, by carrier and invasive Streptococcus agalactiae strains of ST17 and ST19 sequence types, including DNase producers and non-producers. Bacteria ability to assemble biofilms was classified based on crystal violet assay. Biofilm formation was also monitored by scanning electron microscopy. Depending on the growth medium used, each bacterial isolate could fit in different biofilm production categories. Our data showed that optimal conditions for S. agalactiae biofilm assembly were reached after 48 h incubation at pH 7.6 in the presence of glucose and inactivated human plasma. In the presence of inactivated human plasma, the biofilm biomass of ST19 strains experienced a higher increase than ST17 strains. The composition of the extracellular polymeric matrix of the three strongest biofilm producers (all from ST17) was accessed by enzymatic digestion of mature biofilms and proteins were shown to be the predominant component. The detailed identification of the extracellular protein components should contribute to the development of new therapeutic strategies to fight S. agalactiae infections.
Collapse
Affiliation(s)
- Inês Silvestre
- Department of Life Sciences, UCIBIO, Nova School of Science and Technology, 2829-516 Caparica, Portugal; Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisbon, Portugal.
| | - Maria José Borrego
- Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisbon, Portugal.
| | - Luísa Jordão
- Department of Environmental Health, Research and Development Unit, National Institute of Health Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisbon, Portugal.
| |
Collapse
|
8
|
Liu T, Liu J, Liu J, Yang R, Lu X, He X, Shi W, Guo L. Interspecies Interactions Between Streptococcus Mutans and Streptococcus Agalactiae in vitro. Front Cell Infect Microbiol 2020; 10:344. [PMID: 32733820 PMCID: PMC7358462 DOI: 10.3389/fcimb.2020.00344] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/04/2020] [Indexed: 01/30/2023] Open
Abstract
Streptococcus mutans is an oral species closely associated with dental caries. As an early oral colonizer, S. mutans utilizes interspecies coaggregation to promote the colonization of subsequent species and affect polymicrobial pathogenesis. Previous studies have confirmed several adhering partner species of S. mutans, including Candida albicans and Fusobacterium nucleatum. In this study, we discovered new intergeneric co-adherence between S. mutans and the saliva isolate Streptococcus agalactiae (GBS-SI101). Research shows that GBS typically colonizes the human gastrointestinal and vaginal tracts. It is responsible for adverse pregnancy outcomes and life-threatening infections in neonates and immunocompromised people. Our results revealed that GtfB and GtfC of S. mutans, which contributed to extracellular polysaccharide synthesis, promoted coaggregation of S. mutans with GBS-SI101. In addition, oral streptococci, including Streptococcus sanguinis, Streptococcus gordonii and S. mutans, barely inhibited the growth of GBS-SI101. This study indicated that S. mutans could help GBS integrate into the Streptococcus-associated oral polymicrobial community and become a resident species in the oral cavity, increasing the risk of oral infections.
Collapse
Affiliation(s)
- Tingjun Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jia Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jianwei Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Ruiqi Yang
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Xianjun Lu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Xuesong He
- The Forsyth Institute, Cambridge, MA, United States
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Wenyuan Shi
- The Forsyth Institute, Cambridge, MA, United States
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Lihong Guo
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| |
Collapse
|
9
|
Lamba GS, Dufour D, Nainar SMH, Cioffi I, Lévesque CM, Gong SG. Association of Streptococcus mutans collagen binding genes with severe childhood caries. Clin Oral Investig 2020; 24:3467-3475. [DOI: 10.1007/s00784-020-03217-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 01/20/2020] [Indexed: 01/05/2023]
|
10
|
Antimicrobial Properties of Magnesium Open Opportunities to Develop Healthier Food. Nutrients 2019; 11:nu11102363. [PMID: 31623397 PMCID: PMC6835631 DOI: 10.3390/nu11102363] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/15/2019] [Accepted: 09/21/2019] [Indexed: 02/07/2023] Open
Abstract
Magnesium is a vital mineral that takes part in hundreds of enzymatic reactions in the human body. In the past several years, new information emerged in regard to the antibacterial effect of magnesium. Here we elaborate on the recent knowledge of its antibacterial effect with emphasis on its ability to impair bacterial adherence and formation complex community of bacterial cells called biofilm. We further talk about its ability to impair biofilm formation in milk that provides opportunity for developing safer and qualitative dairy products. Finally, we describe the pronounced advantages of enrichment of food with magnesium ions, which result in healthier and more efficient food products.
Collapse
|
11
|
Defining the Role of the Streptococcus agalactiae Sht-Family Proteins in Zinc Acquisition and Complement Evasion. J Bacteriol 2019; 201:JB.00757-18. [PMID: 30745371 DOI: 10.1128/jb.00757-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 01/30/2019] [Indexed: 01/10/2023] Open
Abstract
Streptococcus agalactiae is not only part of the human intestinal and urogenital microbiota but is also a leading cause of septicemia and meningitis in neonates. Its ability to cause disease depends upon the acquisition of nutrients from its environment, including the transition metal ion zinc. The primary zinc acquisition system of the pathogen is the Adc/Lmb ABC permease, which is essential for viability in zinc-restricted environments. Here, we show that in addition to the AdcCB transporter and the three zinc-binding proteins, Lmb, AdcA, and AdcAII, S. agalactiae zinc homeostasis also involves two streptococcal histidine triad (Sht) proteins. Sht and ShtII are required for zinc uptake via the Lmb and AdcAII proteins with apparent overlapping functionality and specificity. Both Sht-family proteins possess five-histidine triad motifs with similar hierarchies of importance for Zn homeostasis. Independent of its contribution to zinc homeostasis, Sht has previously been reported to bind factor H leading to predictions of a contribution to complement evasion. Here, we investigated ShtII to ascertain whether it had similar properties. Analysis of recombinant Sht and ShtII reveals that both proteins have similar affinities for factor H binding. However, neither protein aided in resistance to complement in human blood. These findings challenge prior inferences regarding the in vivo role of the Sht proteins in resisting complement-mediated clearance.IMPORTANCE This study examined the role of the two streptococcal histidine triad (Sht) proteins of Streptococcus agalactiae in zinc homeostasis and complement resistance. We showed that Sht and ShtII facilitate zinc homeostasis in conjunction with the metal-binding proteins Lmb and AdcAII. Here, we show that the Sht-family proteins are functionally redundant with overlapping roles in zinc uptake. Further, this work reveals that although the Sht-family proteins bind to factor H in vitro this did not influence survival in human blood.
Collapse
|
12
|
The Two-Component Signaling System VraSR ss Is Critical for Multidrug Resistance and Full Virulence in Streptococcus suis Serotype 2. Infect Immun 2018; 86:IAI.00096-18. [PMID: 29685990 DOI: 10.1128/iai.00096-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/18/2018] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis has received increasing attention for its involvement in severe human infections worldwide as well as in multidrug resistance. Two-component signaling systems (TCSSs) play important roles in bacterial adaptation to various environmental stimuli. In this study, we identified a novel TCSS located in S. suis serotype 2 (SS2), designated VraSRSS, which is involved in bacterial pathogenicity and susceptibility to antimicrobials. Our data demonstrated that the yvqFSS gene, located upstream of vraSRSS , shared the same promoter with the TCSS genes, which was directly regulated by VraSRSS, as shown in electrophoretic mobility shift assays. Notably, YvqFSS and VraSRSS constitute a novel multidrug resistance module of SS2 that participates in resistance to certain groups of antimicrobials. Further analyses showed that VraSRSS inactivation significantly attenuated bacterial virulence in animal models, which, coupled with the significant activation of VraSRSS expression observed in host blood, strongly suggested that VraSRSS is an important regulator of SS2 pathogenicity. Indeed, RNA-sequencing analyses identified 106 genes that were differentially expressed between the wild-type and ΔvraSRSS strains, including genes involved in capsular polysaccharide (CPS) biosynthesis. Subsequent studies confirmed that VraSRSS indirectly regulated the transcription of CPS gene clusters and, thus, controlled the CPS thickness shown by transmission electron microscopy. Decreased CPS biosynthesis caused by vraSRSS deletion subsequently increased bacterial adhesion to epithelial cells and attenuated antiphagocytosis against macrophages, which partially clarified the pathogenic mechanism mediated by VraSRSS Taken together, our data suggest that the novel TCSS, VraSRSS, plays critical roles for multidrug resistance and full virulence in SS2.
Collapse
|
13
|
Shabayek S, Spellerberg B. Group B Streptococcal Colonization, Molecular Characteristics, and Epidemiology. Front Microbiol 2018; 9:437. [PMID: 29593684 PMCID: PMC5861770 DOI: 10.3389/fmicb.2018.00437] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 02/26/2018] [Indexed: 11/13/2022] Open
Abstract
Streptococcus agalactiae or group B streptococcus (GBS) is a leading cause of serious neonatal infections. GBS is an opportunistic commensal constituting a part of the intestinal and vaginal physiologic flora and maternal colonization is the principal route of GBS transmission. GBS is a pathobiont that converts from the asymptomatic mucosal carriage state to a major bacterial pathogen causing severe invasive infections. At present, as many as 10 serotypes (Ia, Ib, and II–IX) are recognized. The aim of the current review is to shed new light on the latest epidemiological data and clonal distribution of GBS in addition to discussing the most important colonization determinants at a molecular level. The distribution and predominance of certain serotypes is susceptible to variations and can change over time. With the availability of multilocus sequence typing scheme (MLST) data, it became clear that GBS strains of certain clonal complexes possess a higher potential to cause invasive disease, while other harbor mainly colonizing strains. Colonization and persistence in different host niches is dependent on the adherence capacity of GBS to host cells and tissues. Bacterial biofilms represent well-known virulence factors with a vital role in persistence and chronic infections. In addition, GBS colonization, persistence, translocation, and invasion of host barriers are largely dependent on their adherence abilities to host cells and extracellular matrix proteins (ECM). Major adhesins mediating GBS interaction with host cells include the fibrinogen-binding proteins (Fbs), the laminin-binding protein (Lmb), the group B streptococcal C5a peptidase (ScpB), the streptococcal fibronectin binding protein A (SfbA), the GBS immunogenic bacterial adhesin (BibA), and the hypervirulent adhesin (HvgA). These adhesins facilitate persistent and intimate contacts between the bacterial cell and the host, while global virulence regulators play a major role in the transition to invasive infections. This review combines for first time epidemiological data with data on adherence and colonization for GBS. Investigating the epidemiology along with understanding the determinants of mucosal colonization and the development of invasive disease at a molecular level is therefore important for the development of strategies to prevent invasive GBS disease worldwide.
Collapse
Affiliation(s)
- Sarah Shabayek
- Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
| |
Collapse
|
14
|
Ohri M, Parashar S, Pai VS, Ghosh S, Chakraborti A. A cytosol derived factor of Group B streptococcus prevent its invasion into human epithelial cells. World J Microbiol Biotechnol 2018. [PMID: 29520519 DOI: 10.1007/s11274-018-2428-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Group B streptococcus (GBS) or Streptococcus agalactiae, is an opportunistic pathogen causing a wide range of infections like pneumonia, sepsis, and meningitis in newborn, pregnant women and adults. While this bacterium has adapted well to asymptomatic colonization of adult humans, it still remains a potentially devastating pathogen to susceptible infants. Advances in molecular techniques and refinement of in vitro and in vivo model systems have elucidated key elements of the pathogenic process, from initial attachment to the maternal vaginal epithelium to penetration of the newborn blood-brain barrier. Still, the formidable array of GBS virulence factors makes this bacterium at the forefront of neonatal pathogens. The involvement of bacterial components in the host-pathogen interaction of GBS pathogenesis and its related diseases is not clearly understood. In this study we demonstrated the role of a 39 kDa factor from GBS which plays an important role in the process of its invasion. We found a homogeneous 39 kDa factor from the cytosol of GBS after following a combination of sequential purification steps involving molecular sieving and ion exchange chromatography using ACTA-FPLC system. Its N-terminal sequence showed a homology with xenobiotic response element type transcriptional regulator protein, a 40 kDa protein of Streptococcus. This factor leads to inhibition of GBS invasion in HeLa and A549 cells. This protein also showed sensitivity and specific cross reactivity with the antibodies raised against it in New Zealand white rabbits by western immunoblotting. This inhibitory factor was further confirmed tolerant for its cytotoxicity. These results add a novel aspect to bacterial pathogenesis where bacteria's own intracellular protein component can act as a potential therapeutic candidate by decreasing the severity of disease thus promoting its invasion inhibition.
Collapse
Affiliation(s)
- Manju Ohri
- Post Graduate Institute of Medical Education and Research, Chandigarh, India.
| | - Smriti Parashar
- Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | | | - Sujata Ghosh
- Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | | |
Collapse
|
15
|
Shabayek S, Spellerberg B. Acid Stress Response Mechanisms of Group B Streptococci. Front Cell Infect Microbiol 2017; 7:395. [PMID: 28936424 PMCID: PMC5594096 DOI: 10.3389/fcimb.2017.00395] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 08/23/2017] [Indexed: 12/20/2022] Open
Abstract
Group B streptococcus (GBS) is a leading cause of neonatal mortality and morbidity in the United States and Europe. It is part of the vaginal microbiota in up to 30% of pregnant women and can be passed on to the newborn through perinatal transmission. GBS has the ability to survive in multiple different host niches. The pathophysiology of this bacterium reveals an outstanding ability to withstand varying pH fluctuations of the surrounding environments inside the human host. GBS host pathogen interations include colonization of the acidic vaginal mucosa, invasion of the neutral human blood or amniotic fluid, breaching of the blood brain barrier as well as survival within the acidic phagolysosomal compartment of macrophages. However, investigations on GBS responses to acid stress are limited. Technologies, such as whole genome sequencing, genome-wide transcription and proteome mapping facilitate large scale identification of genes and proteins. Mechanisms enabling GBS to cope with acid stress have mainly been studied through these techniques and are summarized in the current review
Collapse
Affiliation(s)
- Sarah Shabayek
- Institute of Medical Microbiology and Hygiene, University of UlmUlm, Germany.,Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal UniversityIsmailia, Egypt
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of UlmUlm, Germany
| |
Collapse
|
16
|
Li Q, Fu Y, He Y, Zhang Y, Qian Y, Yu Y, Yao H, Lu C, Zhang W. Fibronectin-/fibrinogen-binding protein (FBPS) is not a critical virulence factor for the Streptococcus suis serotype 2 strain ZY05719. Vet Microbiol 2017; 208:38-46. [DOI: 10.1016/j.vetmic.2017.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/09/2017] [Accepted: 07/09/2017] [Indexed: 01/06/2023]
|
17
|
Vornhagen J, Adams Waldorf KM, Rajagopal L. Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies. Trends Microbiol 2017. [PMID: 28633864 DOI: 10.1016/j.tim.2017.05.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Group B streptococcus (GBS) or Streptococcus agalactiae is a β-hemolytic, Gram-positive bacterium that is a leading cause of neonatal infections. GBS commonly colonizes the lower gastrointestinal and genital tracts and, during pregnancy, neonates are at risk of infection. Although intrapartum antibiotic prophylaxis during labor and delivery has decreased the incidence of early-onset neonatal infection, these measures do not prevent ascending infection that can occur earlier in pregnancy leading to preterm births, stillbirths, or late-onset neonatal infections. Prevention of GBS infection in pregnancy is complex and is likely influenced by multiple factors, including pathogenicity, host factors, vaginal microbiome, false-negative screening, and/or changes in antibiotic resistance. A deeper understanding of the mechanisms of GBS infections during pregnancy will facilitate the development of novel therapeutics and vaccines. Here, we summarize and discuss important advancements in our understanding of GBS vaginal colonization, ascending infection, and preterm birth.
Collapse
Affiliation(s)
- Jay Vornhagen
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kristina M Adams Waldorf
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
| |
Collapse
|
18
|
Cools P, Melin P. Group B Streptococcus and perinatal mortality. Res Microbiol 2017; 168:793-801. [PMID: 28435137 DOI: 10.1016/j.resmic.2017.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022]
Abstract
The World Health Organization estimates that every year, one million neonatal deaths occur because of neonatal infection. Furthermore, an equal number of stillbirths are thought to be caused by infections. Here we discuss the role of Streptococcus agalactiae (group B Streptococcus, GBS) in neonatal disease and stillbirth.
Collapse
Affiliation(s)
- Piet Cools
- Laboratory Bacteriology Research, Department of Microbiology, Immunology and Clinical Chemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| | - Pierrette Melin
- Clinical Microbiology, National Reference Centre for Streptococcus agalactiae, University Hospital of Liège, Faculty of Medicine, Liege University, Liège, Belgium
| |
Collapse
|
19
|
Potential biomarkers for effective screening of neonatal sepsis infections: An overview. Microb Pathog 2017; 107:234-242. [PMID: 28377234 DOI: 10.1016/j.micpath.2017.03.042] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 12/17/2022]
Abstract
Neonatal sepsis, a clinical disorder developed by bacterial blood stream infections (BSI) in neonates, is one of the serious global public health problems that must be addressed. More than one million of the estimated global newborn deaths per year are occurred due to severe infections. The genesis of the infection is divided into early-onset sepsis (EOS) and late-onset sepsis (LOS) of the disease. The clinical complications of neonatal sepsis may be associated with bronchopulmonary dysplasia, ductus arteriosus and necrotizing enterocolitis. The clinical diagnosis and treatment of neonatal sepsis is highly complicated. Over the past few years distinct biomarkers have been identified. Most widely used biomarkers are C-reactive protein, Procalcitonin (PCT) and Serum amyloid A (SAA). Until recently, many potential biomarkers including Cell Surface antigens and Bacterial surface antigens and genetic biomarkers are being investigated. Protein biomarkers, cytokines and chemokines are getting much interest for identification of neonatal sepsis infection.
Collapse
|
20
|
Li Q, Fu Y, Ma C, He Y, Yu Y, Du D, Yao H, Lu C, Zhang W. The non-conserved region of MRP is involved in the virulence of Streptococcus suis serotype 2. Virulence 2017; 8:1274-1289. [PMID: 28362221 DOI: 10.1080/21505594.2017.1313373] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Muramidase-released protein (MRP) of Streptococcus suis serotype 2 (SS2) is an important epidemic virulence marker with an unclear role in bacterial infection. To investigate the biologic functions of MRP, 3 mutants named Δmrp, Δmrp domain 1 (Δmrp-d1), and Δmrp domain 2 (Δmrp-d2) were constructed to assess the phenotypic changes between the parental strain and the mutant strains. The results indicated that MRP domain 1 (MRP-D1, the non-conserved region of MRP from a virulent strain, a.a. 242-596) played a critical role in adherence of SS2 to host cells, compared with MRP domain 1* (MRP-D1*, the non-conserved region of MRP from a low virulent strain, a.a. 239-598) or MRP domain 2 (MRP-D2, the conserved region of MRP, a.a. 848-1222). We found that MRP-D1 but not MRP-D2, could bind specifically to fibronectin (FN), factor H (FH), fibrinogen (FG), and immunoglobulin G (IgG). Additionally, we confirmed that mrp-d1 mutation significantly inhibited bacteremia and brain invasion in a mouse infection model. The mrp-d1 mutation also attenuated the intracellular survival of SS2 in RAW246.7 macrophages, shortened the growth ability in pig blood and decreased the virulence of SS2 in BALB/c mice. Furthermore, antiserum against MRP-D1 was found to dramatically impede SS2 survival in pig blood. Finally, immunization with recombinant MRP-D1 efficiently enhanced murine viability after SS2 challenge, indicating its potential use in vaccination strategies. Collectively, these results indicated that MRP-D1 is involved in SS2 virulence and eloquently demonstrate the function of MRP in pathogenesis of infection.
Collapse
Affiliation(s)
- Quan Li
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Yang Fu
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Caifeng Ma
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Yanan He
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Yanfei Yu
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Dechao Du
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Huochun Yao
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Chengping Lu
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Wei Zhang
- a Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture , Nanjing Agricultural University , Nanjing , China
| |
Collapse
|
21
|
Factor H specifically capture novel Factor H-binding proteins of Streptococcus suis and contribute to the virulence of the bacteria. Microbiol Res 2016; 196:17-25. [PMID: 28164787 DOI: 10.1016/j.micres.2016.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/31/2016] [Accepted: 11/12/2016] [Indexed: 11/23/2022]
Abstract
Factor H (FH), a regulatory protein of the complement system, can bind specifically to factor H-binding proteins (FHBPs) of Streptococcus suis serotype 2 (SS2), which contribute to evasion of host innate immune defenses. In the present study, we aimed to identify novel FHBPs and characterize the biological functions of FH in SS2 pathogenesis. Here, a method that combined proteomics and Far-western blotting was developed to identify the surface FHBPs of SS2. With this method, fourteen potential novel FHBPs were identified among SS2 surface proteins. We selected eight newly identified proteins and further confirmed their binding activity to FH. The binding of SS2 to immobilized FH decreased dramatically after pre-incubation with anti-FHBPs polyclonal antibodies. We showed for the first time that SS2 also interact specifically with mouse FH. Furthermore, we found that FH play an important role in adherence and invasion of SS2 to HEp-2 cells. Additionally, using a mouse model of intraperitoneal challenge, we confirmed that SS2 pre-incubated with FH enhanced bacteremia and brain invasion, compared with SS2 not pretreated with FH. Taken together, this study provides a useful method to characterize the host-bacteria interactions. These results first indicated that binding of FH to the cell surface improved the adherence and invasion of SS2 to HEp-2 cells, promoting SS2 to resist killing and leading to enhance virulence.
Collapse
|
22
|
The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival. J Bacteriol 2016; 198:3265-3277. [PMID: 27672194 DOI: 10.1128/jb.00614-16] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/16/2016] [Indexed: 12/14/2022] Open
Abstract
The Lmb protein of Streptococcus agalactiae is described as an adhesin that binds laminin, a component of the human extracellular matrix. In this study, we revealed a new role for this protein in zinc uptake. We also identified two Lmb homologs, AdcA and AdcAII, redundant binding proteins that combine with the AdcCB translocon to form a zinc-ABC transporter. Expression of this transporter is controlled by the zinc concentration in the medium through the zinc-dependent regulator AdcR. Triple deletion of lmb, adcA, and adcAII, or that of the adcCB genes, impaired growth and cell separation in a zinc-restricted environment. Moreover, we found that this Adc zinc-ABC transporter promotes S. agalactiae growth and survival in some human biological fluids, suggesting that it contributes to the infection process. These results indicated that zinc has biologically vital functions in S. agalactiae and that, under the conditions tested, the Adc/Lmb transporter constitutes the main zinc acquisition system of the bacterium. IMPORTANCE A zinc transporter, composed of three redundant binding proteins (Lmb, AdcA, and AdcAII), was characterized in Streptococcus agalactiae This system was shown to be essential for bacterial growth and morphology in zinc-restricted environments, including human biological fluids.
Collapse
|
23
|
Barato P, Martins E, Vasquez G, Ramirez M, Melo-Cristino J, Martínez N, Iregui C. Capsule impairs efficient adherence of Streptococcus agalactiae to intestinal epithelium in tilapias Oreochromis sp. Microb Pathog 2016; 100:30-36. [DOI: 10.1016/j.micpath.2016.08.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/30/2016] [Accepted: 08/31/2016] [Indexed: 10/21/2022]
|
24
|
Dehbashi S, Pourmand MR, Mashhadi R. Characterization of Afb, a novel bifunctional protein in Streptococcus agalactiae. IRANIAN JOURNAL OF MICROBIOLOGY 2016; 8:73-9. [PMID: 27092228 PMCID: PMC4833744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND AND OBJECTIVES Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in newborns and results in pneumonia and bacteremia in adults. A number of S. agalactiae components are involved in colonization of target cells. Destruction of peptidoglycan and division of covalently linked daughter cells is mediated by autolysins. In this study, autolytic activity and plasma binding ability of AFb novel recombinant protein of S. agalactiae was investigated. MATERIALS AND METHODS The gbs1805 gene was cloned and expressed. E. coli strains DH5α and BL21 were used as cloning and expression hosts, respectively. After purification, antigenicity and binding ability to plasma proteins of the recombinant protein was evaluated. RESULTS AFb, the 18KDa protein was purified successfully. The insoluble mature protein revealed the ability to bind to fibrinogen and fibronectin. This insoluble mature protein revealed that it has the ability to bind to fibrinogen and fibronectin plasma proteins. Furthermore, in silico analysis demonstrated the AFb has an autolytic activity. CONCLUSIONS AFb is a novel protein capable of binding to fibrinogen and fibronectin. This findings lay a ground work for further investigation of the role of the bacteria in adhesion and colonization to the host.
Collapse
Affiliation(s)
- Sanaz Dehbashi
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Pourmand
- Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran,Corresponding author: Mohammad Reza Pourmand Address: Department of Pathobiology, School of Public Health and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Tel: +98-21- 88954910, E-mail:
| | - Rahil Mashhadi
- Urology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
25
|
Li Q, Liu H, Du D, Yu Y, Ma C, Jiao F, Yao H, Lu C, Zhang W. Identification of Novel Laminin- and Fibronectin-binding Proteins by Far-Western Blot: Capturing the Adhesins of Streptococcus suis Type 2. Front Cell Infect Microbiol 2015; 5:82. [PMID: 26636044 PMCID: PMC4644805 DOI: 10.3389/fcimb.2015.00082] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 10/31/2015] [Indexed: 02/06/2023] Open
Abstract
Bacterial cell wall (CW) and extracellular (EC) proteins are often involved in interactions with extracellular matrix (ECM) proteins such as laminin (LN) and fibronectin (FN), which play important roles in adhesion and invasion. In this study, an efficient method combining proteomic analysis and Far-Western blotting assays was developed to screen directly for bacterial surface proteins with LN- and FN-binding capacity. With this approach, fifteen potential LN-binding proteins and five potential FN-binding proteins were identified from Streptococcus suis serotype 2 (SS2) CW and EC proteins. Nine newly identified proteins, including oligopeptide-binding protein OppA precursor (OppA), elongation factor Tu (EF-Tu), enolase, lactate dehydrogenase (LDH), fructose-bisphosphate aldolase (FBA), 3-ketoacyl-ACP reductase (KAR), Gly ceraldehyde-3-phosphate dehydrogenase (GAPDH), Inosine 5'-monophosphate dehydrogenase (IMPDH), and amino acid ABC transporter permease (ABC) were cloned, expressed, purified and further confirmed by Far-Western blotting and ELISA. Five proteins (OppA, EF-Tu, enolase, LDH, and FBA) exhibited specifically binding activity to both human LN and human FN. Furthermore, seven important recombinant proteins were selected and identified to have the ability to bind Hep-2 cells by the indirect immunofluorescent assay. In addition, four recombinant proteins, and their corresponding polyclonal antibodies, were observed to decrease SS2 adhesion to Hep-2 cells, which indicates that these proteins contribute to the adherence of SS2 to host cell surface. Collectively, these results show that the approach described here represents a useful tool for investigating the host-pathogen interactions.
Collapse
Affiliation(s)
- Quan Li
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Hanze Liu
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Dechao Du
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Yanfei Yu
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Caifeng Ma
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Fangfang Jiao
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Huochun Yao
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Chengping Lu
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| | - Wei Zhang
- Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University Nanjing, China
| |
Collapse
|
26
|
Oknin H, Steinberg D, Shemesh M. Magnesium ions mitigate biofilm formation of Bacillus species via downregulation of matrix genes expression. Front Microbiol 2015; 6:907. [PMID: 26441856 PMCID: PMC4561805 DOI: 10.3389/fmicb.2015.00907] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/19/2015] [Indexed: 11/13/2022] Open
Abstract
The objective of this study was to investigate the effect of Mg(2+) ions on biofilm formation by Bacillus species, which are considered as problematic microorganisms in the food industry. We found that magnesium ions are capable to inhibit significantly biofilm formation of Bacillus species at 50 mM concentration and higher. We further report that Mg(2+) ions don't inhibit bacterial growth at elevated concentrations; hence, the mode of action of Mg(2+) ions is apparently specific to inhibition of biofilm formation. Biofilm formation depends on the synthesis of extracellular matrix, whose production in Bacillus subtilis is specified by two major operons: the epsA-O and tapA operons. We analyzed the effect of Mg(2+) ions on matrix gene expression using transcriptional fusions of the promoters for eps and tapA to the gene encoding β galactosidase. The expression of the two matrix operons was reduced drastically in response to Mg(2+) ions suggesting about their inhibitory effect on expression of the matrix genes in B. subtilis. Since the matrix gene expression is tightly controlled by Spo0A dependent pathway, we conclude that Mg(2+) ions could affect the signal transduction for biofilm formation through this pathway.
Collapse
Affiliation(s)
- Hilla Oknin
- Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization, The Volcani CenterBet-Dagan, Israel
- Biofilm Research Laboratory, Faculty of Dental Medicine, Institute of Dental Sciences, Hebrew University-HadassahJerusalem, Israel
| | - Doron Steinberg
- Biofilm Research Laboratory, Faculty of Dental Medicine, Institute of Dental Sciences, Hebrew University-HadassahJerusalem, Israel
| | - Moshe Shemesh
- Department of Food Quality and Safety, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization, The Volcani CenterBet-Dagan, Israel
| |
Collapse
|
27
|
Acidic pH strongly enhances in vitro biofilm formation by a subset of hypervirulent ST-17 Streptococcus agalactiae strains. Appl Environ Microbiol 2014; 80:2176-85. [PMID: 24487536 DOI: 10.1128/aem.03627-13] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus agalactiae, also known as group B Streptococcus (GBS), is a primary colonizer of the anogenital mucosa of up to 40% of healthy women and an important cause of invasive neonatal infections worldwide. Among the 10 known capsular serotypes, GBS type III accounts for 30 to 76% of the cases of neonatal meningitis. In recent years, the ability of GBS to form biofilm attracted attention for its possible role in fitness and virulence. Here, a new in vitro biofilm formation protocol was developed to guarantee more stringent conditions, to better discriminate between strong-, low-, and non-biofilm-forming strains, and to facilitate interpretation of data. This protocol was used to screen the biofilm-forming abilities of 366 GBS clinical isolates from pregnant women and from neonatal infections of different serotypes in relation to medium composition and pH. The results identified a subset of isolates of serotypes III and V that formed strong biofilms under acidic conditions. Importantly, the best biofilm formers belonged to serotype III hypervirulent clone ST-17. Moreover, the abilities of proteinase K to strongly inhibit biofilm formation and to disaggregate mature biofilms suggested that proteins play an essential role in promoting GBS biofilm initiation and contribute to biofilm structural stability.
Collapse
|
28
|
Carey AJ, Tan CK, Mirza S, Irving-Rodgers H, Webb RI, Lam A, Ulett GC. Infection and cellular defense dynamics in a novel 17β-estradiol murine model of chronic human group B streptococcus genital tract colonization reveal a role for hemolysin in persistence and neutrophil accumulation. THE JOURNAL OF IMMUNOLOGY 2014; 192:1718-31. [PMID: 24453257 DOI: 10.4049/jimmunol.1202811] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Genital tract carriage of group B streptococcus (GBS) is prevalent among adult women; however, the dynamics of chronic GBS genital tract carriage, including how GBS persists in this immunologically active host niche long term, are not well defined. To our knowledge, in this study, we report the first animal model of chronic GBS genital tract colonization using female mice synchronized into estrus by delivery of 17β-estradiol prior to intravaginal challenge with wild-type GBS 874391. Cervicovaginal swabs, which were used to measure bacterial persistence, showed that GBS colonized the vaginal mucosa of mice at high numbers (10(6)-10(7) CFU/swab) for at least 90 d. Cellular and histological analyses showed that chronic GBS colonization of the murine genital tract caused significant lymphocyte and PMN cell infiltrates, which were localized to the vaginal mucosal surface. Long-term colonization was independent of regular hormone cycling. Immunological analyses of 23 soluble proteins related to chemotaxis and inflammation showed that the host response to GBS in the genital tract comprised markers of innate immune activation including cytokines such as GM-CSF and TNF-α. A nonhemolytic isogenic mutant of GBS 874391, Δcyle9, was impaired for colonization and was associated with amplified local PMN responses. Induction of DNA neutrophil extracellular traps, which was observed in GBS-infected human PMNs in vitro in a hemolysin-dependent manner, appeared to be part of this response. Overall, this study defines key infection dynamics in a novel murine model of chronic GBS genital tract colonization and establishes previously unknown cellular and soluble defense responses to GBS in the female genital tract.
Collapse
Affiliation(s)
- Alison J Carey
- School of Medical Sciences, Griffith Health Institute, Griffith University, Gold Coast, Queensland 4222, Australia
| | | | | | | | | | | | | |
Collapse
|
29
|
Wang X, Xiu L, Hu Q, Cui X, Liu B, Tao L, Wang T, Wu J, Chen Y, Chen Y. Deep sequencing-based transcriptional analysis of bovine mammary epithelial cells gene expression in response to in vitro infection with Staphylococcus aureus stains. PLoS One 2013; 8:e82117. [PMID: 24358144 PMCID: PMC3864865 DOI: 10.1371/journal.pone.0082117] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 10/21/2013] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is an important etiological organism in chronic and subclinical mastitis in lactating cows. Given the fundamental role the primary bovine mammary epithelial cells (pBMECs) play as a major first line of defense against invading pathogens, their interactions with S. aureus was hypothesized to be crucial to the establishment of the latter’s infection process. This hypothesis was tested by investigating the global transcriptional responses of pBMECs to three S. aureus strains (S56,S178 and S36) with different virulent factors, using a tag-based high-throughput transcriptome sequencing technique. Approximately 4.9 million total sequence tags were obtained from each of the three S. aureus-infected libraries and the control library. Referenced to the control, 1720, 219, and 427 differentially expressed unique genes were identified in the pBMECs infected with S56, S178 and S36 S. aureus strains respectively. Gene ontology (GO) and pathway analysis of the S56-infected pBMECs referenced to those of the control revealed that the differentially expressed genes in S56-infected pBMECs were significantly involved in inflammatory response, cell signalling pathways and apoptosis. In the same vein, the clustered GO terms of the differentially expressed genes of the S178-infected pBMECs were found to comprise immune responses, metabolism transformation, and apoptosis, while those of the S36-infected pBMECs were primarily involved in cell cycle progression and immune responses. Furthermore, fundamental differences were observed in the levels of expression of immune-related genes in response to treatments with the three S. aureus strains. These differences were especially noted for the expression of important pro-inflammatory molecules, including IL-1α, TNF, EFNB1, IL-8, and EGR1. The transcriptional changes associated with cellular signaling and the inflammatory response in this study may reflect different immunomodulatory mechanisms that underlie the interaction between pBMECs and S. aureus strains during infection by the latter.
Collapse
Affiliation(s)
- Xiao Wang
- College of Life Sciences, Inner Mongolia University, Hohhot, China
- * E-mail:
| | - Lei Xiu
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Qingliang Hu
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Xinjie Cui
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Bingchun Liu
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Lin Tao
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Ting Wang
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Jingging Wu
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Yuan Chen
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Yan Chen
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| |
Collapse
|
30
|
Abstract
Streptococcus agalactiae (group B Streptococcus [GBS]) is a leading cause of neonatal sepsis and meningitis, peripartum infections in women, and invasive infections in chronically ill or elderly individuals. GBS can be isolated from the gastrointestinal or genital tracts of up to 30% of healthy adults, and infection is thought to arise from invasion from a colonized mucosal site. Accordingly, bacterial surface components that mediate attachment of GBS to host cells or the extracellular matrix represent key factors in the colonization and infection of the human host. We identified a conserved GBS gene of unknown function that was predicted to encode a cell wall-anchored surface protein. Deletion of the gene and a cotranscribed upstream open reading frame (ORF) in GBS strain 515 reduced bacterial adherence to VK2 vaginal epithelial cells in vitro and reduced GBS binding to fibronectin-coated microtiter wells. Expression of the gene product in Lactococcus lactis conferred the ability to adhere to VK2 cells, to fibronectin and laminin, and to fibronectin-coated ME-180 cervical epithelial cells. Expression of the recombinant protein in L. lactis also markedly increased biofilm formation. The adherence function of the protein, named bacterial surface adhesin of GBS (BsaB), depended both on a central BID1 domain found in bacterial intimin-like proteins and on the C-terminal portion of the BsaB protein. Expression of BsaB in GBS, like that of several other adhesins, was regulated by the CsrRS two-component system. We conclude that BsaB represents a newly identified adhesin that participates in GBS attachment to epithelial cells and the extracellular matrix.
Collapse
|
31
|
Derré-Bobillot A, Cortes-Perez NG, Yamamoto Y, Kharrat P, Couvé E, Da Cunha V, Decker P, Boissier MC, Escartin F, Cesselin B, Langella P, Bermúdez-Humarán LG, Gaudu P. Nuclease A (Gbs0661), an extracellular nuclease of Streptococcus agalactiae, attacks the neutrophil extracellular traps and is needed for full virulence. Mol Microbiol 2013; 89:518-31. [PMID: 23772975 DOI: 10.1111/mmi.12295] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2013] [Indexed: 12/30/2022]
Abstract
Most bacteria of the genus Streptococcus are opportunistic pathogens, and some of them produce extracellular DNases, which may be important for virulence. Genome analyses of Streptococcus agalactiae (GBS) neonate isolate NEM316 revealed the presence of seven genes putatively encoding secreted DNases, although their functions, if any, are unknown. In this study, we observed that respiration growth of GBS led to the extracellular accumulation of a putative nuclease, identified as being encoded by the gbs0661 gene. When overproduced in Lactococcus lactis, the protein was found to be a divalent cation-requiring, pH-stable and heat-stable nuclease that we named Nuclease A (NucA). Substitution of the histidine(148) by alanine reduced nuclease activity of the GBS wild-type strain, indicating that NucA is the major nuclease ex vivo. We determined that GBS is able to degrade the DNA matrix comprising the neutrophil extracellular trap (NET). The nucA(H148A) mutant was impaired for this function, implicating NucA in the virulence of GBS. In vivo infection studies confirmed that NucA is required for full infection, as the mutant strain allowed increased bacterial clearance from lung tissue and decreased mortality in infected mice. These results show that NucA is involved in NET escape and is needed for full virulence.
Collapse
|
32
|
Krishnan V, Dwivedi P, Kim BJ, Samal A, Macon K, Ma X, Mishra A, Doran KS, Ton-That H, Narayana SVL. Structure of Streptococcus agalactiae tip pilin GBS104: a model for GBS pili assembly and host interactions. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1073-89. [PMID: 23695252 PMCID: PMC3663123 DOI: 10.1107/s0907444913004642] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 02/18/2013] [Indexed: 11/10/2022]
Abstract
The crystal structure of a 75 kDa central fragment of GBS104, a tip pilin from the 2063V/R strain of Streptococcus agalactiae (group B streptococcus; GBS), is reported. In addition, a homology model of the remaining two domains of GBS104 was built and a model of full-length GBS104 was generated by combining the homology model (the N1 and N4 domains) and the crystal structure of the 75 kDa fragment (the N2 and N3 domains). This rod-shaped GBS104 model is constructed of three IgG-like domains (the N1, N2 and N4 domains) and one vWFA-like domain (the N3 domain). The N1 and N2 domains of GBS104 are assembled with distinct and remote segments contributed by the N- and C-termini. The metal-binding site in the N3 domain of GBS104 is in the closed/low-affinity conformation. Interestingly, this domain hosts two long arms that project away from the metal-binding site. Using site-directed mutagenesis, two cysteine residues that lock the N3 domain of GBS104 into the open/high-affinity conformation were introduced. Both wild-type and disulfide-locked recombinant proteins were tested for binding to extracellular matrix proteins such as collagen, fibronectin, fibrinogen and laminin, and an increase in fibronectin binding affinity was identified for the disulfide-locked N3 domain, suggesting that induced conformational changes may play a possible role in receptor binding.
Collapse
Affiliation(s)
- Vengadesan Krishnan
- UNESCO Regional Centre for Biotechnology (RCB), Gurgaon 122 016, Haryana, India
| | - Prabhat Dwivedi
- University of Texas Health Science Center, Houston, TX 77030, USA
| | - Brandon J. Kim
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Alexandra Samal
- Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Kevin Macon
- Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Xin Ma
- University of Texas Health Science Center, Houston, TX 77030, USA
| | - Arunima Mishra
- University of Texas Health Science Center, Houston, TX 77030, USA
| | - Kelly S. Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Hung Ton-That
- University of Texas Health Science Center, Houston, TX 77030, USA
| | - Sthanam V. L. Narayana
- Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| |
Collapse
|
33
|
Zhang H, Ma Z, Li Y, Zheng J, Yi L, Fan H, Lu C. Identification of a novel collagen type І-binding protein from Streptococcus suis serotype 2. Vet J 2013; 197:406-14. [PMID: 23465548 DOI: 10.1016/j.tvjl.2013.01.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 01/21/2013] [Accepted: 01/23/2013] [Indexed: 11/24/2022]
Abstract
Streptococcus suis, a major pathogen of pigs, is an emerging zoonotic agent that causes meningitis and septic shock. cbp40 is a putative virulent gene that has been identified using suppression subtractive hybridization performed on the virulent S. suis serotype 2 strain HA9801 and the avirulent S. suis serotype 2 strain T15. Based on predicted protein features showing a shared conserved domain with the collagen-binding protein Cna of Staphylococcus aureus, Cbp40 is likely to function as a direct mediator of collagen adhesion. Here, the cbp40 gene was cloned and the recombinant protein purified. Western blotting using swine convalescent sera confirmed its role as an immunogenic protein. Collagen binding activity could be detected by western affinity blot and ELISA. Conversely, deletion of the cbp40 gene reduced bacterial adhesion to HEp-2 cells, capacity for biofilm formation, and virulence in a zebrafish infection model. The response of the bEnd.3 cell line to infection with the S. suis serotype 2 strain ZY05719 and the cbp40-knockout strain was evaluated using gene expression arrays. The differentially expressed genes were involved in inflammatory and immune responses, leukocyte adhesion and heterophilic cell adhesion. Collectively, these data suggest that Cbp40 plays an important role as an extracellular matrix adhesion protein that interacts with host cells during infection.
Collapse
Affiliation(s)
- Hui Zhang
- Key Lab Animal Disease Diagnostic and Immunology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | | | | | | | | | | | | |
Collapse
|
34
|
CsrRS and environmental pH regulate group B streptococcus adherence to human epithelial cells and extracellular matrix. Infect Immun 2012; 80:3975-84. [PMID: 22949550 DOI: 10.1128/iai.00699-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Streptococcus agalactiae (group B Streptococcus or GBS) is a common colonizer of the gastrointestinal and genital tracts and an important cause of invasive infections in newborn infants and in adults with predisposing chronic conditions or advanced age. Attachment to epithelial surfaces at mucosal sites is a critical step in the successful colonization of a human host, and regulation of this process is likely to play an important role in both commensalism and dissemination to cause invasive disease. We found that inactivation of the CsrRS (or CovRS) two-component system increased GBS adherence to epithelial cells derived from human vaginal, cervical, and respiratory epithelium, as well as increasing adherence to extracellular matrix proteins and increasing biofilm formation on polystyrene. Neutral (as opposed to acidic) pH enhanced GBS binding to vaginal epithelial cells and to fibrinogen and fibronectin, effects that were partially dependent on CsrRS. The regulatory effects of CsrRS and environmental pH on bacterial adherence correlated with their effects on the expression of multiple surface adhesins, as assessed by quantitative reverse transcription-PCR. We conclude that GBS adherence to epithelial and abiotic surfaces is regulated by the CsrRS two-component system and by environmental pH through their regulatory effects on the expression of bacterial surface adhesins. Dynamic regulation of GBS adherence enhances the organism's adaptability to survival in multiple niches in the human host.
Collapse
|
35
|
Alkuwaity K, Taylor A, Heckels JE, Doran KS, Christodoulides M. Group B Streptococcus interactions with human meningeal cells and astrocytes in vitro. PLoS One 2012; 7:e42660. [PMID: 22900037 PMCID: PMC3416839 DOI: 10.1371/journal.pone.0042660] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 07/10/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of life-threatening neonatal meningitis and survivors often suffer permanent neurological damage. How this organism interacts with the meninges and subsequently with astrocytes that constitute the underlying cortical glia limitans superficialis is not known. METHODOLOGY/PRINCIPAL FINDINGS In this paper, we demonstrate dose-dependent adherence of GBS over time to human meningioma cells and fetal astrocytes in vitro, which was not influenced by expression of either β-haemolysin/cytolysin (β-h/c) toxin, different capsule serotypes or by absence of capsule (p>0.05). Internalization of GBS by both cell types was, however, a slow and an infrequent event (only 0.02-0.4% of associated bacteria were internalised by 9 h). Expression of β-h/c toxin did not play a role in invasion (p>0.05), whereas capsule expression lead to a reduction (p<0.05) in the numbers of intracellular bacteria recovered. GBS strains induced cytotoxicity as demonstrated by the measurement of lactate dehydrogenase (LDH) enzyme release by 9 h and by viable staining. Increasing levels of meningioma cell death correlated with bacterial growth and the phenotype of β-h/c toxin production, i.e. from weakly, to normo- to hyper-haemolytic. However, cytotoxicity was significantly greater (p<0.05) towards astrocytes, and infection with initial MOI≥0.003 induced 70-100% LDH release. By comparing wild-type (β-h/c(+)) and mutant (ΔcylE β-h/c(-)) strains and β-h/c toxin extracts and by using the surfactant dipalmitoylphosphatidylcholine in cytotoxicity inhibition experiments, β-h/c toxin was demonstrated as principally responsible for cell death. CONCLUSIONS/SIGNIFICANCE This study has described key events in the interactions of GBS with meningeal cells and astrocytes in vitro and a major virulence role for β-h/c toxin. Understanding the mechanisms involved will help to identify potential therapies for improving patient survival and for reducing the incidence and severity of neurological sequelae.
Collapse
Affiliation(s)
- Khalil Alkuwaity
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Alexander Taylor
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - John E. Heckels
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Kelly S. Doran
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Myron Christodoulides
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
- * E-mail:
| |
Collapse
|
36
|
The enhancement of biofilm formation in Group B streptococcal isolates at vaginal pH. Med Microbiol Immunol 2012; 202:105-15. [DOI: 10.1007/s00430-012-0255-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 06/28/2012] [Indexed: 01/04/2023]
|
37
|
Yang Q, Porter AJ, Zhang M, Harrington DJ, Black GW, Sutcliffe IC. The impact of pH and nutrient stress on the growth and survival of Streptococcus agalactiae. Antonie van Leeuwenhoek 2012; 102:277-87. [PMID: 22527623 DOI: 10.1007/s10482-012-9736-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 04/05/2012] [Indexed: 11/29/2022]
Abstract
Streptococcus agalactiae is a major neonatal pathogen that is able to colonise various host environments and is associated with both gastrointestinal and vaginal maternal carriage. Maternal vaginal carriage represents the major source for transmission of S. agalactiae to the foetus/neonate and thus is a significant risk factor for neonatal disease. In order to understand factors influencing maternal carriage we have investigated growth and long term survival of S. agalactiae under conditions of low pH and nutrient stress in vitro. Surprisingly, given that vaginal pH is normally <4.5, S. agalactiae was found to survive poorly at low pH and failed to grow at pH 4.3. However, biofilm growth, although also reduced at low pH, was shown to enhance survival of S. agalactiae. Proteomic analysis identified 26 proteins that were more abundant under nutrient stress conditions (extended stationary phase), including a RelE family protein, a universal stress protein family member and four proteins that belong to the Gls24 (PF03780) stress protein family. Cumulatively, these data indicate that novel mechanisms are likely to operate that allow S. agalactiae survival at low pH and under nutrient stress during maternal vaginal colonisation and/or that the bacteria may access a more favourable microenvironment at the vaginal mucosa. As current in vitro models for S. agalactiae growth appear unsatisfactory, novel methods need to be developed to study streptococcal colonisation under physiologically-relevant conditions.
Collapse
Affiliation(s)
- Qian Yang
- School of Life Sciences, University of Northumbria at Newcastle, Newcastle upon Tyne, UK
| | | | | | | | | | | |
Collapse
|
38
|
The collagen-binding protein Cnm is required for Streptococcus mutans adherence to and intracellular invasion of human coronary artery endothelial cells. Infect Immun 2011; 79:2277-84. [PMID: 21422186 DOI: 10.1128/iai.00767-10] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans is considered the primary etiologic agent of dental caries, a global health problem that affects 60 to 90% of the population, and a leading causative agent of infective endocarditis. It can be divided into four different serotypes (c, e, f, and k), with serotype c strains being the most common in the oral cavity. In this study, we demonstrate that in addition to OMZ175 and B14, three other strains (NCTC11060, LM7, and OM50E) of the less prevalent serotypes e and f are able to invade primary human coronary artery endothelial cells (HCAEC). Invasive strains were also significantly more virulent than noninvasive strains in the Galleria mellonella (greater wax worm) model of systemic disease. Interestingly, the invasive strains carried an additional gene, cnm, which was previously shown to bind to collagen and laminin in vitro. Inactivation of cnm rendered the organisms unable to invade HCAEC and attenuated their virulence in G. mellonella. Notably, the cnm knockout strains did not adhere to HCAEC as efficiently as the parental strains did, indicating that the loss of the invasion phenotype observed for the mutants was linked to an adhesion defect. Comparisons of the invasive strains and their respective cnm mutants did not support a correlation between biofilm formation and invasion. Thus, Cnm is required for S. mutans invasion of endothelial cells and possibly represents an important virulence factor of S. mutans that may contribute to cardiovascular infections and pathologies.
Collapse
|
39
|
Sellner J, Täuber MG, Leib SL. Pathogenesis and pathophysiology of bacterial CNS infections. HANDBOOK OF CLINICAL NEUROLOGY 2010; 96:1-16. [PMID: 20109671 DOI: 10.1016/s0072-9752(09)96001-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Johann Sellner
- Department of Neurology, Technische Universität München, Germany
| | | | | |
Collapse
|
40
|
Jamasbi RJ, Taylor NM. Correlation Between the Lipopolysaccharide Expression and Adhesiveness of Clinical Isolates ofPseudomonas aeruginosa. Lab Med 2010. [DOI: 10.1309/lm2uywsobdjwhysu] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
41
|
Koenig JM, Keenan WJ. Group B streptococcus and early-onset sepsis in the era of maternal prophylaxis. Pediatr Clin North Am 2009; 56:689-708, Table of Contents. [PMID: 19501699 PMCID: PMC2702484 DOI: 10.1016/j.pcl.2009.04.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite an era of marked success with universal screening, Group B Streptococcus (GBS) continues to be an important cause of early-onset sepsis, and thus remains a significant public health issue. Improved eradication of GBS colonization and disease may involve universal screening in conjunction with rapid diagnostic technologies or other novel approaches. Given the complications and potential limitations associated with maternal intrapartum prophylaxis, however, vaccines may be the most effective means of preventing neonatal GBS disease. The global utility of conjugated GBS vaccines may be hampered by the variability of serotypes in diverse populations and geographic locations. Modern technologies, such as those involving proteomics and genomic sequencing, are likely to hasten the development of a universal vaccine against GBS.
Collapse
Affiliation(s)
- Joyce M Koenig
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Saint Louis University, Saint Louis, MO 63104, USA.
| | | |
Collapse
|
42
|
Biofilm formation in clinical isolates of group B streptococci from north India. Microb Pathog 2009; 46:321-7. [DOI: 10.1016/j.micpath.2009.04.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 03/20/2009] [Accepted: 04/02/2009] [Indexed: 01/08/2023]
|
43
|
Rajagopal L. Understanding the regulation of Group B Streptococcal virulence factors. Future Microbiol 2009; 4:201-21. [PMID: 19257847 DOI: 10.2217/17460913.4.2.201] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Bacterial infections remain a significant threat to the health of newborns and adults. Group B Streptococci (GBS) are Gram-positive bacteria that are common asymptomatic colonizers of healthy adults. However, this opportunistic organism can also subvert suboptimal host defenses to cause severe invasive disease and tissue damage. The increasing emergence of antibiotic-resistant GBS raises more concerns for sustained measures in treatment of the disease. A number of factors that are important for virulence of GBS have been identified. This review summarizes the functions of some well-characterized virulence factors, with an emphasis on how GBS regulates their expression. Regulatory and signaling molecules are attractive drug targets in the treatment of bacterial infections. Consequently, understanding signaling responses of GBS is essential for elucidation of pathogenesis of GBS infection and for the identification of novel therapeutic agents.
Collapse
Affiliation(s)
- Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington & Seattle Children's Hospital Research Institute, 1900 Ninth Avenue, Seattle, WA 98101-91304, USA.
| |
Collapse
|
44
|
Lactic acid is a potential virulence factor for group B Streptococcus. Microb Pathog 2009; 46:43-52. [DOI: 10.1016/j.micpath.2008.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 10/07/2008] [Accepted: 10/17/2008] [Indexed: 11/22/2022]
|
45
|
Esgleas M, Li Y, Hancock MA, Harel J, Dubreuil JD, Gottschalk M. Isolation and characterization of α-enolase, a novel fibronectin-binding protein from Streptococcus suis. Microbiology (Reading) 2008; 154:2668-2679. [DOI: 10.1099/mic.0.2008/017145-0] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Miriam Esgleas
- Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada
| | - Yuanyi Li
- Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada
| | - Mark A. Hancock
- Sheldon Biotechnology Centre, McGill University, Montreal, Québec, Canada
| | - Josée Harel
- Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada
| | - J. Daniel Dubreuil
- Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada
| | - Marcelo Gottschalk
- Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada
| |
Collapse
|
46
|
Allen CA, Niesel DW, Torres AG. The effects of low-shear stress on Adherent-invasive Escherichia coli. Environ Microbiol 2008; 10:1512-25. [PMID: 18312396 DOI: 10.1111/j.1462-2920.2008.01567.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The impact of low-shear stress (LSS) was evaluated on an Adherent-invasive Escherichia coli clinical isolate (AIEC strain O83:H1) from a Crohn's disease patient. High-aspect ratio vessels (HARVs) were used to model LSS conditions to characterize changes in environmental stress resistance and adhesion/invasive properties. Low-shear stress-grown cultures exhibited enhanced thermal and oxidative stress resistance as well as increased adherence to Caco-2 cells, but no changes in invasion were observed. An AIEC rpoS mutant was constructed to examine the impact of this global stress regulator. The absence of RpoS under LSS conditions resulted in increased sensitivity to oxidative stress while adherence levels were elevated in comparison with the wild-type strain. TnphoA mutagenesis and rpoS complementation were carried out on the rpoS mutant to identify those factors involved in the LSS-induced adherence phenotype. Mutagenesis results revealed that one insertion disrupted the tnaB gene (encoding tryptophan permease) and the rpoS tnaB double mutant exhibited decreased adherence under LSS. Complementation of the tnaB gene, or medium supplemented with exogenous indole, restored adhesion of the rpoS tnaB mutant under LSS conditions. Overall, our study demonstrated how mechanical stresses such as LSS altered AIEC phenotypic characteristics and identified novel functions for some RpoS-regulated proteins.
Collapse
Affiliation(s)
- Christopher A Allen
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA
| | | | | |
Collapse
|
47
|
Burnham CAD, Shokoples SE, Tyrrell GJ. Invasion of HeLa cells by group B streptococcus requires the phosphoinositide-3-kinase signalling pathway and modulates phosphorylation of host-cell Akt and glycogen synthase kinase-3. MICROBIOLOGY-SGM 2008; 153:4240-4252. [PMID: 18048937 DOI: 10.1099/mic.0.2007/008417-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The group B streptococcus (GBS) is an opportunistic bacterial pathogen with the ability to cause invasive disease. While the ability of GBS to invade a number of host-cell types has been clearly demonstrated, the invasion process is not well understood at the molecular level. What has been well established is that modulation of host-cell actin microfilaments is essential for GBS invasion to occur. Phosphoinositide-3 kinase (PI3K) is a key regulator of the cytoskeleton in eukaryotic cells. Our goal in this investigation was to explore the role of the PI3K/Akt signalling pathway in epithelial cell invasion by GBS. The epithelial cell invasion process was mimicked using the HeLa 229 cell-culture model. Treating HeLa cells with chemical inhibitors of PI3K, Akt or Ras prior to bacterial infection inhibited GBS invasion but not attachment; treatment with 30 microM LY294002 (PI3K inhibitor) reduced GBS invasion by 75%, 20 microM L-6-hydroxymethyl-chiro-inositol 2-(R)-2-O-methyl-3-O-octadecylcarbonate (ICIO) (Akt inhibitor) reduced GBS invasion by 50%, and 10 microM manumycin A (Ras inhibitor) inhibited GBS invasion by 90%. Genetic inactivation of the p85alpha or p110alpha PI3K subunits in HeLa cells also reduced GBS invasion by 55 and 30%, respectively. Western blot analysis revealed that phosphorylation of host-cell Akt and glycogen synthase kinase-3 (GSK-3) occurs in response to GBS infection, and that this is mediated upstream by PI3K. Infection of HeLa cells with GBS triggers pro-survival signalling and protects the HeLa cells from camptothecin-induced caspase-3 cleavage. The results from this investigation show that GBS both requires and activates the PI3K/Akt host-cell signalling pathway during invasion of epithelial cells.
Collapse
Affiliation(s)
- Carey-Ann D Burnham
- The Department of Laboratory Medicine and Pathology, The University of Alberta, Edmonton, AB, Canada
| | - Sandra E Shokoples
- The National Centre for Streptococcus, The Provincial Laboratory for Public Health (Microbiology), Edmonton, AB, Canada
| | - Gregory J Tyrrell
- The Department of Medical Microbiology and Immunology, The University of Alberta, Edmonton, AB, Canada.,The National Centre for Streptococcus, The Provincial Laboratory for Public Health (Microbiology), Edmonton, AB, Canada.,The Department of Laboratory Medicine and Pathology, The University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
48
|
Bolduc GR, Madoff LC. The group B streptococcal alpha C protein binds alpha1beta1-integrin through a novel KTD motif that promotes internalization of GBS within human epithelial cells. MICROBIOLOGY-SGM 2008; 153:4039-4049. [PMID: 18048918 DOI: 10.1099/mic.0.2007/009134-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis and meningitis among neonates and a cause of morbidity among pregnant women and immunocompromised adults. GBS epithelial cell invasion is associated with expression of alpha C protein (ACP). Loss of ACP expression results in a decrease in GBS internalization and translocation across human cervical epithelial cells (ME180). Soluble ACP and its 170 amino acid N-terminal region (NtACP), but not the repeat protein RR', bind to ME180 cells and reduce internalization of wild-type GBS to levels obtained with an ACP-deficient isogenic mutant. In the current study, ACP colocalized with alpha(1)beta(1)-integrin, resulting in integrin clustering as determined by laser scanning confocal microscopy. NtACP contains two structural domains, D1 and D2. D1 is structurally similar to fibronectin's integrin-binding region (FnIII10). D1's (KT)D146 motif is structurally similar to the FnIII10 (RG)D1495 integrin-binding motif, suggesting that ACP binds alpha(1)beta(1)-integrin via the D1 domain. The (KT)D146A mutation within soluble NtACP reduced its ability to bind alpha(1)beta(1)-integrin and inhibit GBS internalization within ME180 cells. Thus ACP binding to human epithelial cell integrins appears to contribute to GBS internalization within epithelial cells.
Collapse
Affiliation(s)
- Gilles R Bolduc
- Department of Medicine, Brigham and Women's Hospital, 75 Fransis Street, Boston, MA 02115, USA.,Channing Laboratory, 181 Longwood Avenue, Boston, MA 02115, USA
| | - Lawrence C Madoff
- Department of Medicine, Brigham and Women's Hospital, 75 Fransis Street, Boston, MA 02115, USA.,Channing Laboratory, 181 Longwood Avenue, Boston, MA 02115, USA
| |
Collapse
|
49
|
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]
|
50
|
Tronchin G, Pihet M, Lopes-Bezerra LM, Bouchara JP. Adherence mechanisms in human pathogenic fungi. Med Mycol 2008; 46:749-72. [DOI: 10.1080/13693780802206435] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|