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Distribution and Prevalence of Serotypes of Group B Streptococcus Isolated from Pregnant Women in 30 Countries: A Systematic Review. MATERNAL-FETAL MEDICINE 2023. [DOI: 10.1097/fm9.0000000000000174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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Akt Inhibition Promotes Autophagy and Clearance of Group B Streptococcus from the Alveolar Epithelium. Pathogens 2022; 11:pathogens11101134. [PMID: 36297190 PMCID: PMC9611837 DOI: 10.3390/pathogens11101134] [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: 08/03/2022] [Revised: 09/24/2022] [Accepted: 09/27/2022] [Indexed: 12/04/2022] Open
Abstract
Group B Streptococcus (GBS) is a gram-positive bacterium that is harmless for healthy individuals but may provoke invasive disease in young infants and immunocompromised hosts. GBS invades the epithelial barriers to enter the bloodstream, and thus strategies that enhance epithelial cell responses may hamper GBS invasion. In the present study, we sought to investigate whether the inhibition of Akt, a kinase that regulates host inflammatory responses and autophagy via suppression of mTOR, can enhance the response of non-phagocytic alveolar epithelial cells against GBS. Treatment of the alveolar epithelial cell line A549 with the Akt inhibitor MK-2206 resulted in the enhanced production of reactive oxygen species and inflammatory mediators in response to GBS. Additionally, Akt inhibition via MK-2206 resulted in elevated LC3II/I ratios and increased autophagic flux in alveolar epithelial cells. Importantly, the inhibition of Akt promoted GBS clearance both in alveolar epithelial cells in vitro and in lung tissue in vivo in a murine model of GBS pneumonia. The induction of autophagy was essential for GBS clearance in MK-2206 treated cells, as knockdown of ATG5, a critical component of autophagy, abrogated the effect of Akt inhibition on GBS clearance. Our findings highlight the role of Akt kinase inhibition in promoting autophagy and GBS clearance in the alveolar epithelium. The inhibition of Akt may serve as a promising measure to strengthen epithelial barriers and prevent GBS invasion in susceptible hosts.
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Rajaei A, Rowe HM, Neely MN. The LCP Family Protein, Psr, Is Required for Cell Wall Integrity and Virulence in Streptococcus agalactiae. Microorganisms 2022; 10:microorganisms10020217. [PMID: 35208672 PMCID: PMC8875755 DOI: 10.3390/microorganisms10020217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 02/04/2023] Open
Abstract
A robust cell envelope is the first line of protection for an infecting pathogen when encountering the immune defense of its host. In Gram-positive organisms, LytR-CpsA-Psr (LCP) family proteins play a major role in the synthesis and assembly of the cell envelope. While these proteins could be considered for potential new drug targets, not enough is known about how they function to support the integrity of the cell wall. Streptococcus agalactiae (group B streptococcus or GBS) is known to encode at least three LCP family proteins, including CpsA, LytR (BrpA) and Psr. Using strains of GBS that have mutations in two of the three LCP proteins, we were able to determine a role for these proteins in GBS cell wall integrity. The results presented here demonstrate that the absence of Psr results in a decreased growth rate, decreased viability over time, inconsistent cocci morphology and diminished cell wall integrity, as well as an increased penicillin susceptibility, decreased capsule levels and attenuation in virulence in a zebrafish model of infectious disease. A strain that is missing two of the LCP family proteins, CpsA and Psr, exhibits an increase in these defective phenotypes, indicating that CpsA and Psr are partially redundant in function.
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Affiliation(s)
- Atefeh Rajaei
- Molecular and Biomedical Sciences Department, University of Maine, Orono, ME 04469, USA;
| | - Hannah M. Rowe
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA;
| | - Melody N. Neely
- Molecular and Biomedical Sciences Department, University of Maine, Orono, ME 04469, USA;
- Correspondence:
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Determinants of Group B streptococcal virulence potential amongst vaginal clinical isolates from pregnant women. PLoS One 2019; 14:e0226699. [PMID: 31851721 PMCID: PMC6919605 DOI: 10.1371/journal.pone.0226699] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/03/2019] [Indexed: 11/19/2022] Open
Abstract
Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a Gram-positive bacterium isolated from the vaginal tract of approximately 25% of women. GBS colonization of the female reproductive tract is of particular concern during pregnancy as the bacteria can invade gestational tissues or be transmitted to the newborn during passage through the birth canal. Infection of the neonate can result in life-threatening pneumonia, sepsis and meningitis. Thus, surveillance of GBS strains and corresponding virulence potential during colonization is warranted. Here we describe a panel of GBS isolates from the vaginal tracts of a cohort of pregnant women in Michigan, USA. We determined that capsular serotypes III and V were the most abundant across the strain panel, with only one isolate belonging to serotype IV. Further, 12.8% of strains belonged to the hyper-virulent serotype III, sequence type 17 (ST-17) and 15.4% expressed the serine rich repeat glycoprotein-encoding gene srr2. Functional assessment of the colonizing isolates revealed that almost all strains exhibited some level of β-hemolytic activity and that ST-17 strains, which express Srr2, exhibited increased bacterial adherence to vaginal epithelium. Finally, analysis of strain antibiotic susceptibility revealed the presence of antibiotic resistance to penicillin (15.4%), clindamycin (30.8%), erythromycin (43.6%), vancomycin (30.8%), and tetracycline (94.9%), which has significant implications for treatment options. Collectively, these data provide important information on vaginal GBS carriage isolate virulence potential and highlight the value of continued surveillance.
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Gkentzi D, Kortsalioudaki C, Cailes BC, Zaoutis T, Kopsidas J, Tsolia M, Spyridis N, Siahanidou S, Sarafidis K, Heath PT, Dimitriou G. Epidemiology of infections and antimicrobial use in Greek Neonatal Units. Arch Dis Child Fetal Neonatal Ed 2019; 104:F293-F297. [PMID: 29954881 DOI: 10.1136/archdischild-2018-315024] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 06/07/2018] [Accepted: 06/09/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To describe the epidemiology of neonatal infections and of antimicrobial use in Greek Neonatal Units (NNUs) in order to develop national, evidence-based guidelines on empiric antimicrobial use for neonatal sepsis in Greece. DESIGN Retrospective analysis of prospectively collected infection surveillance data from 2012 to 2015, together with a Point Prevalence Survey (PPS) on antimicrobial use and the collection of data on local empiric antimicrobial policies. SETTING 16 NNUs in Greece participating in the neonIN infection surveillance network PATIENTS: Newborns in participating NNUs who had a positive blood, cerebrospinal fluid or urine culture and were treated with at least 5 days of antibiotics. RESULTS 459 episodes were recorded in 418 infants. The overall incidence of infection was 50/1000 NNU-admissions. The majority of episodes were late-onset sepsis (LOS) (413, 90%). Coagulase-negative Staphylococci (80%) were the most common Gram-positive organisms causing LOS and Klebsiella spp (39%) the most common Gram-negative. Nearly half (45%) of the Klebsiella spp were resistant to at least one aminoglycoside. The PPS revealed that 196 of 484 (40%) neonates were on antimicrobials. The survey revealed wide variation in empiric antimicrobial policies for LOS. CONCLUSIONS This is the largest collection of data on the epidemiology of neonatal infections in Greece and on neonatal antimicrobial use. It provides the background for the development of national evidence-based guidelines. Continuous surveillance, the introduction of antimicrobial stewardship interventions and evidence-based guidelines are urgently required.
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Affiliation(s)
- Despoina Gkentzi
- Department of Paediatrics, Patras Medical School, University Hospital of Patras, Patras, Greece
| | | | | | - Theoklis Zaoutis
- The Stavros Niarchos Foundation-Collaborative Centre for Clinical Epidemiology and Outcomes Research, School of Medicine, University of Athens, Athens, Greece
| | - John Kopsidas
- The Stavros Niarchos Foundation-Collaborative Centre for Clinical Epidemiology and Outcomes Research, School of Medicine, University of Athens, Athens, Greece
| | - Maria Tsolia
- Paediatric Infectious Diseases Unit, Aglaia Kyriakou Children's Hospital, Athens, Greece
| | - Nikos Spyridis
- Paediatric Infectious Diseases Unit, Aglaia Kyriakou Children's Hospital, Athens, Greece
| | - Soultana Siahanidou
- Neonatal Unit, First Department of Pediatrics, Athens University Medical School, Athens, Greece
| | - Kosmas Sarafidis
- 1st Department of Neonatology and Neonatal Intensive Care Unit, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Paul T Heath
- Paediatric Infectious Diseases Research Group, St George's University of London, London, UK
| | - Gabriel Dimitriou
- Department of Paediatrics, Patras Medical School, University Hospital of Patras, Patras, Greece
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Serotype, Genotype, and Clinical Manifestations of Group B Streptococcus (GBS) Isolated from Neonates in China. IRANIAN JOURNAL OF PEDIATRICS 2018. [DOI: 10.5812/ijp.14580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Jiang H, Chen M, Li T, Liu H, Gong Y, Li M. Molecular Characterization of Streptococcus agalactiae Causing Community- and Hospital-Acquired Infections in Shanghai, China. Front Microbiol 2016; 7:1308. [PMID: 27625635 PMCID: PMC5003847 DOI: 10.3389/fmicb.2016.01308] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/08/2016] [Indexed: 12/21/2022] Open
Abstract
Streptococcus agalactiae, a colonizing agent in pregnant women and the main cause of neonatal sepsis and meningitis, has been increasingly associated with invasive disease in nonpregnant adults. We collected a total of 87 non-repetitive S. agalactiae isolates causing community-acquired (CA) and hospital-acquired (HA) infections in nonpregnant adults from a teaching hospital in Shanghai between 2009 and 2013. We identified and characterized their antibiotic resistance, sequence type (ST), serotype, virulence, and biofilm formation. The most frequent STs were ST19 (29.9%), ST23 (16.1%), ST12 (13.8%), and ST1 (12.6%). ST19 had significantly different distributions between CA- and HA-group B Streptococci (GBS) isolates. The most frequent serotypes were III (32.2%), Ia (26.4%), V (14.9%), Ib (13.8%), and II (5.7%). Serotype III/ST19 was significantly associated with levofloxacin resistance in all isoates. The HA-GBS multidrug resistant rate was much higher than that of CA-GBS. Virulence genes pavA, cfb were found in all isolates. Strong correlations exist between serotype Ib (CA and HA) and surface protein genes spb1 and bac, serotype III (HA) and surface protein gene cps and GBS pilus cluster. The serotype, epidemic clone, PFGE-based genotype, and virulence gene are closely related between CA-GBS and HA-GBS, and certain serotypes and clone types were significantly associated with antibiotic resistance. However, CA-GBS and HA-GBS still had significant differences in their distribution of clone types, antibiotic resistance, and specific virulence genes, which may provide a basis for infection control.
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Affiliation(s)
- Haoqin Jiang
- Department of Laboratory Medicine, Shanghai Medical College, Huashan Hospital, Fudan University Shanghai, China
| | - Mingliang Chen
- Shanghai Municipal Center for Disease Control and PreventionShanghai, China; Shanghai Institutes of Preventive MedicineShanghai, China
| | - Tianming Li
- Department of Laboratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University Shanghai, China
| | - Hong Liu
- Department of Laboratory Medicine, Shanghai Medical College, Huashan Hospital, Fudan University Shanghai, China
| | - Ye Gong
- Department of Critical Care Medicine, Shanghai Medical College, Huashan Hospital, Fudan University Shanghai, China
| | - Min Li
- Department of Laboratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiao Tong University Shanghai, China
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Modification of the CpsA protein reveals a role in alteration of the Streptococcus agalactiae cell envelope. Infect Immun 2015; 83:1497-506. [PMID: 25644003 DOI: 10.1128/iai.02656-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The bacterial cell envelope is a crucial first line of defense for a systemic pathogen, with production of capsular polysaccharides and maintenance of the peptidoglycan cell wall serving essential roles in survival in the host environment. The LytR-CpsA-Psr proteins are important for cell envelope maintenance in many Gram-positive species. In this study, we examined the role of the extracellular domain of the CpsA protein of the zoonotic pathogen group B Streptococcus in capsule production and cell wall integrity. CpsA has multiple functional domains, including a DNA-binding/transcriptional activation domain and a large extracellular domain. We demonstrated that episomal expression of extracellularly truncated CpsA causes a dominant-negative effect on capsule production when expressed in the wild-type strain. Regions of the extracellular domain essential to this phenotype were identified. The dominant-negative effect could be recapitulated by addition of purified CpsA protein or a short CpsA peptide to cultures of wild-type bacteria. Changes in cell wall morphology were also observed when the dominant-negative peptide was added to wild-type cultures. Fluorescently labeled CpsA peptide could be visualized bound at the mid-cell region near the division septae, suggesting a novel role for CpsA in cell division. Finally, expression of truncated CpsA also led to attenuation of virulence in zebrafish models of infection, to levels below that of a cpsA deletion strain, demonstrating the key role of the extracellular domain in virulence of GBS.
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