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Sereme Y, Schrimp C, Faury H, Agapoff M, Lefebvre-Wloszczowski E, Chang Marchand Y, Ageron-Ardila E, Panafieu E, Blec F, Coureuil M, Frapy E, Tsatsaris V, Bonacorsi S, Skurnik D. A live attenuated vaccine to prevent severe neonatal Escherichia coli K1 infections. Nat Commun 2024; 15:3021. [PMID: 38589401 PMCID: PMC11001983 DOI: 10.1038/s41467-024-46775-x] [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: 08/25/2023] [Accepted: 03/11/2024] [Indexed: 04/10/2024] Open
Abstract
Preterm birth is currently the leading cause of neonatal morbidity and mortality. Genetic, immunological and infectious causes are suspected. Preterm infants have a higher risk of severe bacterial neonatal infections, most of which are caused by Escherichia coli an in particular E. coli K1strains. Women with history of preterm delivery have a high risk of recurrence and therefore constitute a target population for the development of vaccine against E. coli neonatal infections. Here, we characterize the immunological, microbiological and protective properties of a live attenuated vaccine candidate in adult female mice and their pups against after a challenge by K1 and non-K1 strains of E. coli. Our results show that the E. coli K1 E11 ∆aroA vaccine induces strong immunity, driven by polyclonal bactericidal antibodies. In our model of meningitis, mothers immunized prior to mating transfer maternal antibodies to pups, which protect newborn mice against various K1 and non-K1 strains of E. coli. Given the very high mortality rate and the neurological sequalae associated with neonatal E. coli K1 meningitis, our results constitute preclinical proof of concept for the development of a live attenuated vaccine against severe E. coli infections in women at risk of preterm delivery.
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Affiliation(s)
- Youssouf Sereme
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France
| | - Cécile Schrimp
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France
| | - Helène Faury
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France
- Department of Microbiology, Necker Hospital, University de Paris, Paris, France
| | - Maeva Agapoff
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France
| | | | | | | | - Emilie Panafieu
- LEAT antenne Imagine- SFR Necker INSERM US 24, Paris, France
| | - Frank Blec
- LEAT antenne Imagine- SFR Necker INSERM US 24, Paris, France
| | - Mathieu Coureuil
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France
| | - Eric Frapy
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France
| | - Vassilis Tsatsaris
- Maternité Port-Royal, hôpital Cochin, GHU Centre Paris cité, AP-HP, Paris, France
- FHU PREMA, Maternité Port-Royal, Paris, France
| | - Stephane Bonacorsi
- IAME, UMR 1137, INSERM, Université Paris Cité, Paris, France
- Laboratoire de Microbiologie, Hôpital Robert Debré, AP-HP, Paris, France
| | - David Skurnik
- Université Paris Cité, CNRS, INSERM, Institut Necker Enfants Malades, Paris, France.
- Department of Microbiology, Necker Hospital, University de Paris, Paris, France.
- FHU PREMA, Maternité Port-Royal, Paris, France.
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2
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Abstract
The skin microbiome is rich in opportunities for novel therapeutics for skin diseases, and synthetic biology offers the advantage of providing novel functionality or therapeutic benefit to live biotherapeutic products. The development of novel bacterial strains whose growth can be controlled without the use of antibiotics or genetic elements conferring antibiotic resistance enables modulation of therapeutic exposure and improves safety. This study presents the design and in vitro evidence of a skin commensal whose growth can be controlled through d-alanine. The basis of this strain will support future clinical studies of this strain in humans. Using live microbes as therapeutic candidates is a strategy that has gained traction across multiple therapeutic areas. In the skin, commensal microorganisms play a crucial role in maintaining skin barrier function, homeostasis, and cutaneous immunity. Alterations of the homeostatic skin microbiome are associated with a number of skin diseases. Here, we present the design of an engineered commensal organism, Staphylococcus epidermidis, for use as a live biotherapeutic product (LBP) candidate for skin diseases. The development of novel bacterial strains whose growth can be controlled without the use of antibiotics or genetic elements conferring antibiotic resistance enables modulation of therapeutic exposure and improves safety. We therefore constructed an auxotrophic strain of S. epidermidis that requires exogenously supplied d-alanine. The S. epidermidis NRRL B-4268 Δalr1 Δalr2 Δdat strain (SEΔΔΔ) contains deletions of three biosynthetic genes: two alanine racemase genes, alr1 and alr2 (SE1674 and SE1079), and the d-alanine aminotransferase gene, dat (SE1423). These three deletions restricted growth in d-alanine-deficient medium, pooled human blood, and skin. In the presence of d-alanine, SEΔΔΔ colonized and increased expression of human β-defensin 2 in cultured human skin models in vitro. SEΔΔΔ showed a low propensity to revert to d-alanine prototrophy and did not form biofilms on plastic in vitro. These studies support the potential safety and utility of SEΔΔΔ as a live biotherapeutic strain whose growth can be controlled by d-alanine. IMPORTANCE The skin microbiome is rich in opportunities for novel therapeutics for skin diseases, and synthetic biology offers the advantage of providing novel functionality or therapeutic benefit to live biotherapeutic products. The development of novel bacterial strains whose growth can be controlled without the use of antibiotics or genetic elements conferring antibiotic resistance enables modulation of therapeutic exposure and improves safety. This study presents the design and in vitro evidence of a skin commensal whose growth can be controlled through d-alanine. The basis of this strain will support future clinical studies of this strain in humans.
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3
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Volpe V, Giacomodonato MN, Sordelli DO, Insausti M, Buzzola FR, Grünhut M. Ciprofloxacin loaded o/w microemulsion against Staphylococcus aureus. Analytical and biological studies for topical and intranasal administration. J Drug Deliv Sci Technol 2020. [DOI: 10.1016/j.jddst.2020.101705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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4
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Melnikov VG, Villena J, Kombarova SY. [The problem of decolonization of Staphylococcus aureus nasal carriers from the microbiologist's point of view (review of literature).]. Klin Lab Diagn 2019; 64:693-699. [PMID: 31747501 DOI: 10.18821/0869-2084-2019-64-11-693-699] [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: 10/16/2019] [Accepted: 10/18/2019] [Indexed: 11/17/2022]
Abstract
Staphylococcus aureus asymptomatically persists on the nasal mucosa, and also causes serious diseases in carriers (endogenous infection) and in patients in a hospital (nosocomial infection). Decolonization of nasal carriers of S. aureus is an important measure aimed at reducing the incidence of staphylococcal infections. Carriage is a form of nasal dysbiosis, therefore, the effectiveness of antibiotics for the decolonization of carriers, by definition, is low. The review discusses the prospects of using probiotics to restore the nasal microbiota. The commercial production of nasal probiotics has not yet been established, but developments in this direction are being carried out in different countries. The experimental substantiation of the possibility of using corynebacteria and other representatives of the nasal microbiota for the decolonization of staphylococcal carriers is presented, as well as the authors' ideas on how to improve the methods of microbial therapy. In particular, it was proposed to use biofilm probiotics, autoprobiotics, and autovaccines for this purpose.
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Affiliation(s)
- V G Melnikov
- G.N. Gabrichevsky Research Institute for Epidemiology and Microbiology of Rospotrebnadzor, 125212, Moscow, Russian Federation
| | - J Villena
- Immunobiotics Research Group, Reference Centre for Lactobacilli (CERELA-CONICET), 980-0845, Tucuman, Argentina
| | - S Y Kombarova
- G.N. Gabrichevsky Research Institute for Epidemiology and Microbiology of Rospotrebnadzor, 125212, Moscow, Russian Federation
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5
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Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation. Sci Rep 2019; 9:13479. [PMID: 31530887 PMCID: PMC6748969 DOI: 10.1038/s41598-019-49981-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/02/2019] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is a major cause of bovine mastitis, commonly leading to long-lasting, persistent and recurrent infections. Thereby, S. aureus constantly refines and permanently adapts to the bovine udder environment. In this work, we followed S. aureus within-host adaptation over the course of three months in a naturally infected dairy cattle with chronic, subclinical mastitis. Whole genome sequence analysis revealed a complete replacement of the initial predominant variant by another isogenic variant. We report for the first time within-host evolution towards a sigma factor SigB-deficient pathotype in S. aureus bovine mastitis, associated with a single nucleotide polymorphism in rsbU (G368A → G122D), a contributor to SigB-functionality. The emerged SigB-deficient pathotype exhibits a substantial shift to new phenotypic traits comprising strong proteolytic activity and poly-N-acetylglucosamine (PNAG)-based biofilm production. This possibly unlocks new nutritional resources and promotes immune evasion, presumably facilitating extracellular persistence within the host. Moreover, we observed an adaptation towards attenuated virulence using a mouse infection model. This study extends the role of sigma factor SigB in S. aureus pathogenesis, so far described to be required for intracellular persistence during chronic infections. Our findings suggest that S. aureus SigB-deficiency is an alternative mechanism for persistence and underpin the clinical relevance of staphylococcal SigB-deficient variants which are consistently isolated during human chronic infections.
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6
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Dastmalchi Saei H, Safari E. Methicillin resistance and clonal diversity of Staphylococcus aureus isolated from nasal samples of healthy horses in Iran. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-019-01484-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Chronic rhinosinusitis with nasal polyps is characterized by dysbacteriosis of the nasal microbiota. Sci Rep 2018; 8:7926. [PMID: 29784985 PMCID: PMC5962583 DOI: 10.1038/s41598-018-26327-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 05/04/2018] [Indexed: 02/07/2023] Open
Abstract
Chronic rhinosinusitis with nasal polyp (CRSwNP) patients are often characterized by asthma comorbidity and a type-2 inflammation of the sinonasal mucosa. The mucosal microbiota has been suggested to be implicated in the persistence of inflammation, but associations have not been well defined. To compare the bacterial communities of healthy subjects with CRSwNP patients, we collected nasal swabs from 17 healthy subjects, 21 CRSwNP patients without asthma (CRSwNP-A), and 20 CRSwNP patients with co-morbid asthma (CRSwNP+A). We analysed the microbiota using high-throughput sequencing of the bacterial 16S rRNA. Bacterial communities were different between the three groups. Haemophilus influenzae was significantly enriched in CRSwNP patients, Propionibacterium acnes in the healthy group; Staphylococcus aureus was abundant in the CRSwNP-A group, even though present in 57% of patients. Escherichia coli was found in high amounts in CRSwNP+A patients. Nasal tissues of CRSwNP+A patients expressed significantly higher concentrations of IgE, SE-IgE, and IL-5 compared to those of CRSwNP-A patients. Co-cultivation demonstrated that P. acnes growth was inhibited by H. influenzae, E. coli and S. aureus. The nasal microbiota of healthy subjects are different from those of CRSwNP-A and CRSwNP+A patients. However, the most abundant species in healthy status could not inhibit those in CRSwNP disease.
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Khamash DF, Voskertchian A, Milstone AM. Manipulating the microbiome: evolution of a strategy to prevent S. aureus disease in children. J Perinatol 2018; 38:105-109. [PMID: 29120455 PMCID: PMC5790614 DOI: 10.1038/jp.2017.155] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/21/2017] [Accepted: 08/30/2017] [Indexed: 12/12/2022]
Abstract
Hospitalized infants have the highest rates of invasive Staphylococcus aureus disease of any population and infection control strategies such as decolonization have been insufficient. For decades, researchers began studying the microbiome in search of new prevention strategies. The resident microbiota was found to be closely associated with susceptibility and at times, resistance to S. aureus colonization. The evolution of nucleic acid based techniques has enhanced our understanding of the complex relationship between the nasal microbiota and S. aureus colonization. We review what is known about bacterial communities in the nasal cavity of infants and discuss how future microbiome studies may help identify novel interventions to protect high-risk infants from S. aureus disease.
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Affiliation(s)
- Dina F. Khamash
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Annie Voskertchian
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Aaron M. Milstone
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Hospital Epidemiology and Infection Control, Johns Hopkins Hospital, Baltimore, MD
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9
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Dotto C, Lombarte Serrat A, Cattelan N, Barbagelata MS, Yantorno OM, Sordelli DO, Ehling-Schulz M, Grunert T, Buzzola FR. The Active Component of Aspirin, Salicylic Acid, Promotes Staphylococcus aureus Biofilm Formation in a PIA-dependent Manner. Front Microbiol 2017; 8:4. [PMID: 28167931 PMCID: PMC5253544 DOI: 10.3389/fmicb.2017.00004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 01/03/2017] [Indexed: 01/10/2023] Open
Abstract
Aspirin has provided clear benefits to human health. But salicylic acid (SAL) -the main aspirin biometabolite- exerts several effects on eukaryote and prokaryote cells. SAL can affect, for instance, the expression of Staphylococcus aureus virulence factors. SAL can also form complexes with iron cations and it has been shown that different iron chelating molecules diminished the formation of S. aureus biofilm. The aim of this study was to elucidate whether the iron content limitation caused by SAL can modify the S. aureus metabolism and/or metabolic regulators thus changing the expression of the main polysaccharides involved in biofilm formation. The exposure of biofilm to 2 mM SAL induced a 27% reduction in the intracellular free Fe2+ concentration compared with the controls. In addition, SAL depleted 23% of the available free Fe2+ cation in culture media. These moderate iron-limited conditions promoted an intensification of biofilms formed by strain Newman and by S. aureus clinical isolates related to the USA300 and USA100 clones. The slight decrease in iron bioavailability generated by SAL was enough to induce the increase of PIA expression in biofilms formed by methicillin-resistant as well as methicillin-sensitive S. aureus strains. S. aureus did not produce capsular polysaccharide (CP) when it was forming biofilms under any of the experimental conditions tested. Furthermore, SAL diminished aconitase activity and stimulated the lactic fermentation pathway in bacteria forming biofilms. The polysaccharide composition of S. aureus biofilms was examined and FTIR spectroscopic analysis revealed a clear impact of SAL in a codY-dependent manner. Moreover, SAL negatively affected codY transcription in mature biofilms thus relieving the CodY repression of the ica operon. Treatment of mice with SAL induced a significant increase of S aureus colonization. It is suggested that the elevated PIA expression induced by SAL might be responsible for the high nasal colonization observed in mice. SAL-induced biofilms may contribute to S. aureus infection persistence in vegetarian individuals as well as in patients that frequently consume aspirin.
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Affiliation(s)
- Cristian Dotto
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Andrea Lombarte Serrat
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Natalia Cattelan
- Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata La Plata, Argentina
| | - María S Barbagelata
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Osvaldo M Yantorno
- Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata La Plata, Argentina
| | - Daniel O Sordelli
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine Vienna, Austria
| | - Tom Grunert
- Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine Vienna, Austria
| | - Fernanda R Buzzola
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
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Côté-Gravel J, Brouillette E, Obradović N, Ster C, Talbot BG, Malouin F. Characterization of a vraG Mutant in a Genetically Stable Staphylococcus aureus Small-Colony Variant and Preliminary Assessment for Use as a Live-Attenuated Vaccine against Intrammamary Infections. PLoS One 2016; 11:e0166621. [PMID: 27855187 PMCID: PMC5113970 DOI: 10.1371/journal.pone.0166621] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 11/01/2016] [Indexed: 12/14/2022] Open
Abstract
Staphylococcus aureus is a leading cause of bovine intramammary infections (IMIs) that can evolve into difficult-to-treat chronic mastitis. To date, no vaccine formulation has shown high protective efficacy against S. aureus IMI, partly because this bacterium can efficiently evade the immune system. For instance, S. aureus small colony variants (SCVs) have intracellular abilities and can persist without producing invasive infections. As a first step towards the development of a live vaccine, this study describes the elaboration of a novel attenuated mutant of S. aureus taking advantage of the SCV phenotype. A genetically stable SCV was created through the deletion of the hemB gene, impairing its ability to adapt and revert to the invasive phenotype. Further attenuation was obtained through inactivation of gene vraG (SACOL0720) which we previously showed to be important for full virulence during bovine IMIs. After infection of bovine mammary epithelial cells (MAC-T), the double mutant (ΔvraGΔhemB) was less internalized and caused less cell destruction than that seen with ΔhemB and ΔvraG, respectively. In a murine IMI model, the ΔvraGΔhemB mutant was strongly attenuated, with a reduction of viable counts of up to 5-log10 CFU/g of mammary gland when compared to the parental strain. A complete clearance of ΔvraGΔhemB from glands was observed whereas mortality rapidly (48h) occurred with the wild-type strain. Immunization of mice using subcutaneous injections of live ΔvraGΔhemB raised a strong immune response as judged by the high total IgG titers measured against bacterial cell extracts and by the high IgG2a/IgG1 ratio observed against the IsdH protein. Also, ΔvraGΔhemB had sufficient common features with bovine mastitis strains so that the antibody response also strongly recognized strains from a variety of mastitis associated spa types. This double mutant could serve as a live-attenuated component in vaccines to improve cell-mediated immune responses against S. aureus IMIs.
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Affiliation(s)
- Julie Côté-Gravel
- Centre d’Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Brouillette
- Centre d’Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Nataša Obradović
- Centre d’Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Céline Ster
- Centre d’Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Brian G. Talbot
- Centre d’Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - François Malouin
- Centre d’Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
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11
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Aromatic Compound-Dependent Staphylococcus aureus Is Safe in a Nasal Colonization Leukopenic Murine Model. Int J Microbiol 2012; 2012:468539. [PMID: 22927858 PMCID: PMC3420127 DOI: 10.1155/2012/468539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 06/28/2012] [Accepted: 06/28/2012] [Indexed: 11/18/2022] Open
Abstract
Staphylococcus aureus nasal carriage is a risk factor for individuals suffering from trauma, surgical procedures, invasive devices, and/or decreased immunity. Recently, we demonstrated that artificial nasal colonization with an attenuated S. aureus mutant reduced by bacterial interference with the colonization of pathogenic strains of S. aureus. This could be an optional tool to diminish the rate of S. aureus infections in hospitalized patients. The aim of this study was to construct a safe ΔaroA mutant of S. aureus and to discriminate it from nasal colonizing and osteomyelitis S. aureus isolates by SmaI pulsed-field gel electrophoresis (PFGE) typing. The ΔaroA mutant, named RD17, exhibited an LD(50) (3.2 × 10(6) colony-forming unit (CFU)) significantly higher than that of the parental strain (2.2 × 10(3) CFU). The colony number of the RD17 mutants recovered from nares of leukopenic mice was similar to that observed in the animals of the control group. Therefore, the ΔaroA mutant was demonstrated to be safe due to maintaining low growth levels in the nares regardless of immune status of the animals. PFGE typing allowed the unequivocal identification of the S. aureus and differentiation of aroA mutants in nasal colonizing and osteomyelitis isolates. This information could be important to discriminate endogenous infections from laboratory strains of S. aureus.
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12
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Hurd AF, Garcia-Lara J, Rauter Y, Cartron M, Mohamed R, Foster SJ. The iron-regulated surface proteins IsdA,IsdB, and IsdH are not required for heme iron utilization in Staphylococcus aureus. FEMS Microbiol Lett 2012; 329:93-100. [DOI: 10.1111/j.1574-6968.2012.02502.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 01/11/2012] [Accepted: 01/13/2012] [Indexed: 01/29/2023] Open
Affiliation(s)
- Alexander F. Hurd
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield; UK
| | - Jorge Garcia-Lara
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield; UK
| | - Yvonne Rauter
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield; UK
| | - Michaël Cartron
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield; UK
| | - Ramlan Mohamed
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield; UK
| | - Simon J. Foster
- Krebs Institute, Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield; UK
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