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Goh KGK, Desai D, Thapa R, Prince D, Acharya D, Sullivan MJ, Ulett GC. An opportunistic pathogen under stress: how Group B Streptococcus responds to cytotoxic reactive species and conditions of metal ion imbalance to survive. FEMS Microbiol Rev 2024; 48:fuae009. [PMID: 38678005 PMCID: PMC11098048 DOI: 10.1093/femsre/fuae009] [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: 08/31/2023] [Revised: 03/26/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024] Open
Abstract
Group B Streptococcus (GBS; also known as Streptococcus agalactiae) is an opportunistic bacterial pathogen that causes sepsis, meningitis, pneumonia, and skin and soft tissue infections in neonates and healthy or immunocompromised adults. GBS is well-adapted to survive in humans due to a plethora of virulence mechanisms that afford responses to support bacterial survival in dynamic host environments. These mechanisms and responses include counteraction of cell death from exposure to excess metal ions that can cause mismetallation and cytotoxicity, and strategies to combat molecules such as reactive oxygen and nitrogen species that are generated as part of innate host defence. Cytotoxicity from reactive molecules can stem from damage to proteins, DNA, and membrane lipids, potentially leading to bacterial cell death inside phagocytic cells or within extracellular spaces within the host. Deciphering the ways in which GBS responds to the stress of cytotoxic reactive molecules within the host will benefit the development of novel therapeutic and preventative strategies to manage the burden of GBS disease. This review summarizes knowledge of GBS carriage in humans and the mechanisms used by the bacteria to circumvent killing by these important elements of host immune defence: oxidative stress, nitrosative stress, and stress from metal ion intoxication/mismetallation.
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Affiliation(s)
- Kelvin G K Goh
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Devika Desai
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Ruby Thapa
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Darren Prince
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Dhruba Acharya
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
| | - Matthew J Sullivan
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Glen C Ulett
- School of Pharmacy and Medical Sciences, and Menzies Health Institute Queensland, Griffith University, Parklands Drive, Southport, Gold Coast Campus, QLD 4222, Australia
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2
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Simões LC, Fernandes FG, de Oliveira ICM, de Almeida Corrêa AB, Costa NS, Oliveira LMA, Botelho ACN, Fracalanzza SEL, Teixeira LM, Pinto TCA. Characteristics of Streptococcus agalactiae belonging to CC103 clone circulating among dairy herds and pregnant women in Brazil. Braz J Microbiol 2023; 54:2505-2508. [PMID: 37249815 PMCID: PMC10485183 DOI: 10.1007/s42770-023-01017-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 05/24/2023] [Indexed: 05/31/2023] Open
Affiliation(s)
- Leandro Corrêa Simões
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, Brazil
| | - Flávio Gimenis Fernandes
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, Brazil
| | | | | | - Natália Silva Costa
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, Brazil
| | | | - Ana Caroline Nunes Botelho
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, Brazil
| | | | - Lucia Martins Teixeira
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, Brazil
| | - Tatiana Castro Abreu Pinto
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Rio de Janeiro, Brazil.
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3
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Bonsaglia ECR, Rossi RS, Latosinski G, Rossi BF, Campos FC, Junior AF, Pantoja JCF, Rall VLM. Relationship between Biofilm Production and High Somatic Cell Count in Streptococcus agalactiae Isolated from Milk of Cows with Subclinical Mastitis. Pathogens 2023; 12:pathogens12020311. [PMID: 36839583 PMCID: PMC9966988 DOI: 10.3390/pathogens12020311] [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] [Received: 10/27/2022] [Revised: 01/30/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023] Open
Abstract
Streptococcus agalactiae (S. agalactiae) is one of the main agents that causes mastitis in dairy cows, mainly inducing the subclinical form, which is characterized by a high somatic cell count (SCC). The aim of this study was to correlate the increase in SCC caused by S. agalactiae in cows with subclinical mastitis to the presence of genes related to adhesion and invasion in bovine mammary epithelial cells (BMEC) and biofilm formation. Considering the 145 isolates tested, 57.2% presented the capsular type Ia and 42.8% presented type III. We identified the virulence genes among the isolates and determined nine genetic profiles. The most common profile was identified in 69 isolates (47.5%): Ia, fbsA+, fbsB-, pI1-, pI2a-, pI2b+, and hylb+. All isolates produced biofilm, with 58.6% classified as strong producers, 29% as moderate producers and 12.4% as weak producers. No statistical correlation was found between the presence of virulence genes and increased SCC or biofilm production. However, biological evidence was observed between increased SCC and biofilm production. One isolate from each profile was randomly subjected to adhesion and invasion assays, and all of them adhered to BEMC, but none were able to invade. Our results showed that different genetic profiles do not provide advantages for bacteria to invade BMEC in vitro. In addition, biofilm production appears to be related to high SCC.
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Affiliation(s)
- Erika Carolina Romão Bonsaglia
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
- Correspondence: (E.C.R.B.); (V.L.M.R.); Tel.: +5514-3880-0438 (V.L.M.R.)
| | - Rodolfo S. Rossi
- Department of Veterinary Hygiene and Public Health, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
| | - Giulia Latosinski
- Department of Veterinary Hygiene and Public Health, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
| | - Bruna Fernanda Rossi
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
| | - Fernanda Cristina Campos
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
| | - Ary Fernandes Junior
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
| | - José Carlos F. Pantoja
- Department of Veterinary Hygiene and Public Health, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
| | - Vera Lucia Mores Rall
- Department of Chemical and Biological Sciences, Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
- Correspondence: (E.C.R.B.); (V.L.M.R.); Tel.: +5514-3880-0438 (V.L.M.R.)
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4
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Liang T, Huo G, Chen L, Ding L, Wu J, Zhang J, Wang R. Antibacterial activity and metabolomic analysis of linalool against bovine mastitis pathogen Streptococcus agalactiae. Life Sci 2023; 313:121299. [PMID: 36535400 DOI: 10.1016/j.lfs.2022.121299] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/05/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Streptococcus agalactiae is among the major causative pathogens of bovine mastitis, as well as crucial pathogen leading to human morbidity and mortality. Being a promising natural antibacterial agent, linalool has been broadly applied in medicine and food processing. However, its antibacterial effect against S. agalactiae has barely been elucidated. This study is the first to investigate the antibacterial activity and action mechanism of linalool against S. agalactiae causing bovine mastitis. Linalool exhibited significant antibacterial activity against S. agalactiae, with an inhibition zone diameter of 23 mm and a minimum inhibitory concentration of 1.875 μL/mL. In addition, linalool damaged cell structural integrity of S. agalactiae, leading to the leakage of intracellular components (alkaline phosphatase, nucleic acids and protein). Linalool also exhibited a scavenging effect on biofilm. Moreover, untargeted metabolomics analysis revealed that linalool stress substantially disrupted intracellular metabolism of S. agalactiae. Linalool caused energy metabolism disorder, and obstructed nucleic acid synthesis in S. agalactiae. Furthermore, downregulation of amino acids (e.g., proline, alanine) and upregulation of saturated fatty acids provide strong evidence for linalool induced cell wall and membrane damage. Overall, linalool exhibited strong antibacterial activity against S. agalactiae by destroying the cell structure and disrupting intracellular metabolism. This study provides a new insight and theoretical foundation for linalool application in preventing S. agalactiae infection.
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Affiliation(s)
- Tingyu Liang
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China; New Rural Development Research Institute of Northwest Normal University, Lanzhou 730070, PR China
| | - Guiguo Huo
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China
| | - Lele Chen
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China
| | - Ling Ding
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China
| | - Jianping Wu
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China; New Rural Development Research Institute of Northwest Normal University, Lanzhou 730070, PR China.
| | - Ji Zhang
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China; New Rural Development Research Institute of Northwest Normal University, Lanzhou 730070, PR China.
| | - Rongmin Wang
- College of Life Science, Northwest Normal University, Lanzhou 730070, PR China; New Rural Development Research Institute of Northwest Normal University, Lanzhou 730070, PR China; College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, PR China.
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Alvim DCSS, Oliveira LMA, Simões LC, Costa NS, Fracalanzza SEL, Teixeira LM, Ferreira RBR, Pinto TCA. Influence of Penicillin on Biofilm Formation by Streptococcus agalactiae Serotype Ia/CC23. Microb Drug Resist 2022; 28:517-524. [PMID: 35263182 DOI: 10.1089/mdr.2021.0238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Streptococcus agalactiae (Group B Streptococcus , GBS) is a major agent of perinatal infections. Biofilms have been associated with GBS colonization and disease, as well as with infection persistence and recurrence. Although GBS remains susceptible to beta-lactams, it is still unknown how sessile cells respond to these antibiotics. Here, we evaluated the effect of different concentrations of penicillin (3-48 mg/L) on in vitro biofilm formation by four GBS strains belonging to serotype Ia/clonal complexes23 that were recovered from the oropharynx or urine of pregnant women and were previously characterized as strong biofilm producers. All four GBS strains were fully susceptible to penicillin (minimum inhibitory concentration = 0.023 mg/L), but penicillin was not able to fully prevent biofilm formation by these GBS strains. Biofilms formed in the presence of penicillin had reduced biomasses and thickness, but they were still classified as strong. Penicillin significantly reduced the density of live cells, but higher penicillin concentrations did not lead to improved prevention of biofilm formation. Biofilms formed in the presence of penicillin had no channels or long cocci chains observed in penicillin-free biofilms. Overall, results highlight the concerning possible impacts of biofilm formation in penicillin-based treatment and preventive strategies of GBS infections, even when the bacterial strain involved is fully antibiotic-susceptible.
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Affiliation(s)
| | | | - Leandro Corrêa Simões
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Natalia Silva Costa
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Lucia Martins Teixeira
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Tatiana Castro Abreu Pinto
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Ferreira MNMR, de Paula GR, Barros RR. Distribution of virulence determinants in Streptococcus agalactiae recovered from different clinical sources. Microb Pathog 2021; 161:105255. [PMID: 34678459 DOI: 10.1016/j.micpath.2021.105255] [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: 07/15/2021] [Revised: 10/05/2021] [Accepted: 10/13/2021] [Indexed: 11/25/2022]
Abstract
Streptococcus agalactiae (group B Streptococcus, GBS) is a pathobiont, a member of human microbiota that can change from commensal to pathogen, causing a large spectrum of diseases. This study assessed virulence determinants of 32 GBS isolates recovered from different clinical sources associated with asymptomatic and symptomatic clinical outcomes that present distinct capsular types and antimicrobial resistance profiles. The ability of a unique strain to colonize and cause infection in different subjects was also evaluated. By PFGE analysis, it was observed that a given strain could be associated with both asymptomatic and symptomatic outcomes. Cell wall anchor proteins β and alpha C encoding genes (bac and bca, respectively) were detected in all capsular type Ib isolates. bca was more frequent among asymptomatic outcome-related isolates, as well as high expression of β-hemolysin/cytolysin (β-H/C). Symptomatic outcome-related isolates produced strong biofilm more frequently. All bacterial isolates recovered from urine were strong biofilm producers. In growth experiments, asymptomatic outcome-related isolates grew faster after 2 h until the end of the log phase. Taken together, these findings show virulence genotypic and phenotypic features of GBS from distinct sources, which may be helpful to understand their pathogenic potential and predict different clinical outcomes.
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Affiliation(s)
- Mariana Nunes M R Ferreira
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Brazil
| | - Geraldo Renato de Paula
- Departamento de Tecnologia Farmacêutica, Faculdade de Farmácia, Universidade Federal Fluminense, Brazil
| | - Rosana Rocha Barros
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Brazil.
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Asadpoor M, Ithakisiou GN, van Putten JPM, Pieters RJ, Folkerts G, Braber S. Antimicrobial Activities of Alginate and Chitosan Oligosaccharides Against Staphylococcus aureus and Group B Streptococcus. Front Microbiol 2021; 12:700605. [PMID: 34589067 PMCID: PMC8473942 DOI: 10.3389/fmicb.2021.700605] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/17/2021] [Indexed: 12/22/2022] Open
Abstract
The bacterial pathogens Streptococcus agalactiae (GBS) and Staphylococcus aureus (S. aureus) cause serious infections in humans and animals. The emergence of antibiotic-resistant isolates and bacterial biofilm formation entails the urge of novel treatment strategies. Recently, there is a profound scientific interest in the capabilities of non-digestible oligosaccharides as antimicrobial and anti-biofilm agents as well as adjuvants in antibiotic combination therapies. In this study, we investigated the potential of alginate oligosaccharides (AOS) and chitosan oligosaccharides (COS) as alternative for, or in combination with antibiotic treatment. AOS (2-16%) significantly decreased GBS V growth by determining the minimum inhibitory concentration. Both AOS (8 and 16%) and COS (2-16%) were able to prevent biofilm formation by S. aureus wood 46. A checkerboard biofilm formation assay demonstrated a synergistic effect of COS and clindamycin on the S. aureus biofilm formation, while AOS (2 and 4%) were found to sensitize GBS V to trimethoprim. In conclusion, AOS and COS affect the growth of GBS V and S. aureus wood 46 and can function as anti-biofilm agents. The promising effects of AOS and COS in combination with different antibiotics may offer new opportunities to combat antimicrobial resistance.
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Affiliation(s)
- Mostafa Asadpoor
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Georgia-Nefeli Ithakisiou
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Jos P. M. van Putten
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Roland J. Pieters
- Division of Medicinal Chemistry and Chemical Biology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Gert Folkerts
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Saskia Braber
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
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Simões LC, Silva ACP, Santos CM, Alvim DCSS, Nery DCM, Oliveira LMA, Teixeira LM, Pinto TCA. Unusual finding of the human-adapted hypervirulent serotype III/ST17 clone in a historical bovine Group B Streptococcus isolate from Brazil. Braz J Microbiol 2021; 52:1631-1635. [PMID: 34164798 DOI: 10.1007/s42770-021-00529-9] [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: 01/07/2021] [Accepted: 05/12/2021] [Indexed: 10/21/2022] Open
Abstract
Group B Streptococcus (GBS) is a leading cause of human neonatal infections and bovine mastitis. We report here the unusual finding of the human-adapted hypervirulent serotype III/ST17 clone in a bovine GBS isolated in 1987 in Brazil. This isolate shared several phenotypic and genotypic characteristics with serotype III/ST17 strains obtained from human sources, including PFGE pattern, pilus genes, lactose fermentation, DNase activity, and antimicrobial susceptibility profile, highlighting the importance of continued tracking of GBS in the One Health scope. The study brings new evidence for the potential interspecies transmission and sheds new light into evolution aspects of the pathogen Group B Streptococcus (GBS) by reporting the occurrence of an ancient bovine GBS isolate belonging to a variant currently known to be exclusively found in human hosts.
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Affiliation(s)
- Leandro Correa Simões
- Instituto de Microbiologia Paulo de Goes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Carolina Pires Silva
- Instituto de Microbiologia Paulo de Goes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Crislaine Mateus Santos
- Instituto de Microbiologia Paulo de Goes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Débora Costa Morato Nery
- Instituto de Microbiologia Paulo de Goes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Lucia Martins Teixeira
- Instituto de Microbiologia Paulo de Goes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tatiana Castro Abreu Pinto
- Instituto de Microbiologia Paulo de Goes, Universidade Federal Do Rio de Janeiro, Rio de Janeiro, Brazil.
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Deciphering Streptococcal Biofilms. Microorganisms 2020; 8:microorganisms8111835. [PMID: 33233415 PMCID: PMC7700319 DOI: 10.3390/microorganisms8111835] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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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.
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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.
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