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Hofstee MI, Siverino C, Saito M, Meghwani H, Tapia-Dean J, Arveladze S, Hildebrand M, Rangel-Moreno J, Riool M, Zeiter S, Zaat SAJ, Moriarty TF, Muthukrishnan G. Staphylococcus aureus Panton-Valentine Leukocidin worsens acute implant-associated osteomyelitis in humanized BRGSF mice. JBMR Plus 2024; 8:ziad005. [PMID: 38505530 PMCID: PMC10945728 DOI: 10.1093/jbmrpl/ziad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/21/2024] Open
Abstract
Staphylococcus aureus is the most common pathogen that causes implant-associated osteomyelitis, a clinically incurable disease. Immune evasion of S. aureus relies on various mechanisms to survive within the bone niche, including the secretion of leukotoxins such as Panton-Valentine leukocidin (PVL). PVL is a pore-forming toxin exhibiting selective human tropism for C5a receptors (C5aR1 and C5aR2) and CD45 on neutrophils, monocytes, and macrophages. PVL is an important virulence determinant in lung, skin and soft tissue infections. The involvement of PVL in S. aureus pathogenesis during bone infections has not been studied extensively yet. To investigate this, humanized BALB/c Rag2-/-Il2rg-/-SirpaNODFlk2-/- (huBRGSF) mice were subjected to transtibial implant-associated osteomyelitis with community-acquired methicillin-resistant S. aureus (CA-MRSA) USA300 wild type strain (WT), an isogenic mutant lacking lukF/S-PV (Δpvl), or complemented mutant (Δpvl+pvl). Three days post-surgery, Δpvl-infected huBRGSF mice had a less severe infection compared to WT-infected animals as characterized by 1) improved clinical outcomes, 2) lower ex vivo bacterial bone burden, 3) absence of staphylococcal abscess communities (SACs) in their bone marrow, and 4) compromised MRSA dissemination to internal organs (liver, kidney, spleen, heart). Interestingly, Δpvl-infected huBRGSF mice had fewer human myeloid cells, neutrophils, and HLA-DR+ monocytes in the bone niche compared to WT-infected animals. Expectedly, a smaller fraction of human myeloid cells were apoptotic in the Δpvl-infected huBRGSF animals. Taken together, our study highlights the pivotal role of PVL during acute implant-associated osteomyelitis in humanized mice.
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Affiliation(s)
- Marloes I Hofstee
- AO Research Institute Davos, 7270 Davos, Switzerland
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC, Amsterdam institute for Infection and Immunity, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | | | - Motoo Saito
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, United States
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14618, United States
| | - Himanshu Meghwani
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, United States
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14618, United States
| | | | | | | | - Javier Rangel-Moreno
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, University of Rochester Medical Center, Rochester, NY 14620, United States
| | - Martijn Riool
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC, Amsterdam institute for Infection and Immunity, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Trauma Surgery, University Hospital Regensburg, 93053 Regensburg, Germany
| | | | - Sebastian A J Zaat
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC, Amsterdam institute for Infection and Immunity, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | | | - Gowrishankar Muthukrishnan
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY 14642, United States
- Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14618, United States
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
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Liu H, Ji X, Wang H, Hou X, Sun H, Billington C, Zhang L, Wang X, Wang R. Genomic epidemiology and characterization of Staphylococcus aureus isolates from raw milk in Jiangsu, China: emerging broader host tropism strain clones ST59 and ST398. Front Microbiol 2023; 14:1266715. [PMID: 37808296 PMCID: PMC10556526 DOI: 10.3389/fmicb.2023.1266715] [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: 07/25/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Staphylococcus aureus is highly pathogenic and can cause disease in both humans and domestic animals. The aim of this study was to investigate the genomic epidemiology of S. aureus isolates from raw milk in Jiangsu Province, China, to identify predominant lineages and their associated genomic and phenotypic characteristics. In this study, we identified 117 S. aureus isolates collected from 1,062 samples in Jiangsu Province between 2021 and 2022. Based on whole-genome sequencing (WGS) data from 117 S. aureus isolates, molecular analyses indicated CC1-ST1 (26.50%, 31/117), CC97-ST97 (18.80%, 22/117), CC398-ST398 (10.26%, 12/117), CC8-ST630 (7.69%, 9/117) and CC59-ST59 (2.56%, 3/117) were the major lineages. The prevalence of mecA-positive strains was 11.11%. Four methicillin-resistant S. aureus (MRSA) lineages were found, including MRSA-ST59-t172 (n = 3), OS-MRSA-ST398-t011 (n = 1), MRSA-ST630-t2196 (n = 2) and OS-MRSA-ST630-t2196 (n = 7). Phenotypic resistance to penicillin (30.77%, 36/117), ciprofloxacin (17.09%, 20/117) and erythromycin (15.38%, 18/117) was observed which corresponded with resistance genotypes. All of the isolates could produce biofilms, and 38.46% (45/117) of isolates had invasion rates in mammary epithelial cells (MAC-T) of greater than 1%. Interestingly, most biofilm-producing and invading isolates harbored ebp-icaA-icaB-icaC-icaR-clfA-clfB-fnbA-fnbB-sdrC-sdrD-sdrE-map-can (27.35%, 32/117) and ebp-icaA-icaB-icaC-icaD-icaR-clfA-clfB-fnbA-fnbB-sdrC-sdrD-sdrE-map (33.33%, 39/117) adherence-associated gene patterns and belonged to lineages CC1 and CC97, respectively. Virulence factor assays showed that 47.01% of the isolates contained at least enterotoxin genes. Isolates harboring the immune evasion cluster (IEC) genes (sea, sak, chp, and scn) were predominantly categorized as STs 464, 398, and 59. IEC-positive ST398 and ST59 isolates contained a very high proportion of virulence genes located on prophages, whereas most IEC-negative ST398 clade isolates carried broad-spectrum drug resistance genes. Meanwhile, the IEC-positive ST398 clade showed a close genetic relationship with isolates from the pork supply chain and hospital surgical site infections. MRSA-ST59 strains showed the closest genetic relationship with an isolate from quick-frozen products. High-risk livestock-associated strains ST398 and MRSA-ST59 were detected in raw milk, indicating a potential public health risk of S. aureus transmission between livestock and humans. Our study highlights the necessity for S. aureus surveillance in the dairy industry.
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Affiliation(s)
- Hui Liu
- College of Animal Science and Technology, Guangxi University, Nanning, Guangxi, China
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xing Ji
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Heye Wang
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xiang Hou
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Haichang Sun
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Craig Billington
- Institute of Environmental Science and Research, Ilam, Christchurch, New Zealand
| | - Lili Zhang
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xiaoye Wang
- College of Animal Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Ran Wang
- Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
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Shaghayegh G, Cooksley C, Bouras G, Nepal R, Houtak G, Panchatcharam BS, Fenix KA, Psaltis AJ, Wormald PJ, Vreugde S. Staphylococcus aureus biofilm properties and chronic rhinosinusitis severity scores correlate positively with total CD4+ T-cell frequencies and inversely with its Th1, Th17 and regulatory cell frequencies. Immunology 2023; 170:120-133. [PMID: 37191458 DOI: 10.1111/imm.13655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/17/2023] [Indexed: 05/17/2023] Open
Abstract
Chronic rhinosinusitis (CRS) represents chronic inflammation of the sinus mucosa characterised by dysfunction of the sinuses' natural defence mechanisms and induction of different inflammatory pathways ranging from a Th1 to a Th2 predominant polarisation. Recalcitrant CRS is associated with Staphylococcus aureus dominant mucosal biofilms; however, S. aureus colonisation of the sinonasal mucosa has also been observed in healthy individuals challenging the significance of S. aureus in CRS pathogenesis. We aimed to investigate the relationship between CRS key inflammatory markers, S. aureus biofilm properties/virulence genes and the severity of the disease. Tissue samples were collected during endoscopic sinus surgery from the ethmoid sinuses of CRS patients with (CRSwNP) and without (CRSsNP) nasal polyps and controls (n = 59). CD3+ T-cell subset frequencies and key inflammatory markers of CD4+ helper T cells were determined using FACS analysis. Sinonasal S. aureus clinical isolates were isolated (n = 26), sequenced and grown into biofilm in vitro, followed by determining their properties, including metabolic activity, biomass, colony-forming units and exoprotein production. Disease severity was assessed using Lund-Mackay radiologic scores, Lund-Kennedy endoscopic scores and SNOT22 quality of life scores. Our results showed that S. aureus biofilm properties and CRS severity scores correlated positively with total CD4+ T-cell frequencies but looking into CD4+ T-cell subsets showed an inverse correlation with Th1 and Th17 cell frequencies. CD4+ T-cell frequencies were higher in patients harbouring lukF.PV-positive S. aureus while its regulatory and Th17 cell subset frequencies were lower in patients carrying sea- and sarT/U-positive S. aureus. Recalcitrant CRS is characterised by increased S. aureus biofilm properties in relation to increased total CD4+ helper T-cell frequencies and reduced frequencies of its Th1, Th17 and regulatory T-cell subsets. These findings offer insights into the pathophysiology of CRS and could lead to the development of more targeted therapies.
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Affiliation(s)
- Gohar Shaghayegh
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Clare Cooksley
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - George Bouras
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Roshan Nepal
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Ghais Houtak
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Beula Subashini Panchatcharam
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Kevin Aaron Fenix
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Alkis James Psaltis
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Peter-John Wormald
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
| | - Sarah Vreugde
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia
- The Department of Surgery-Otolaryngology, Head and Neck Surgery, The Basil Hetzel Institute for Translational Health Research, Woodville South, Australia
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In Vivo Pathogenicity of Methicillin-Susceptible Staphylococcus aureus Strains Carrying Panton-Valentine Leukocidin Gene. LIFE (BASEL, SWITZERLAND) 2022; 12:life12122126. [PMID: 36556491 PMCID: PMC9780921 DOI: 10.3390/life12122126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/07/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Toxin-producing Staphylococcus aureus strains posing a potential risk for public health have long been a topic of scientific research. Effects of Panton-Valentine leukocidin (PVL) on tissue destruction mechanisms and activities of inflammatory cells were presented in animal models of pneumonia and skin infections induced by PVL-producing S. aureus strains. This study aimed to demonstrate the in vivo pathogenicity of PVL-producing S. aureus strains isolated from some foodstuffs, which can be a potential risk to public health. PVL-positive methicillin-susceptible S. aureus (MSSA) strains M1 and YF1B-b isolated from different foodstuffs and a PVL-positive MSSA strain HT480 (positive control) were administered to New Zealand rabbits. Blood samples were harvested three and six hours after the intratracheal inoculation. Lung tissue samples were collected for gross and microscopic exams and immunohistochemical (IHC) demonstration of IL-6, IL8, IL-10, and TNF-α expressions. Serum cytokine levels were also measured by ELISA. The strains isolated from lung tissue samples were confirmed by pulsed-field gel electrophoresis. The development of acute necrotising pneumonia and a significant elevation in IL-6, IL-8, IL-10, and TNF-α expressions demonstrated the significance of foodborne PVL-positive MSSA strains in public health for the first time.
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Florianova M, Korena K, Juricova H. Whole-genome analysis of methicillin-resistant and methicillin-sensitive Staphylococcus aureus in dry-fermented salami. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.114042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Xie S, Zhang Y, Xu L, Li S, Shen X, Li L, Deng X, Zhou Y. Acacetin attenuates Streptococcus suis virulence by simultaneously targeting suilysin and inflammation. Microb Pathog 2021; 162:105354. [PMID: 34896203 DOI: 10.1016/j.micpath.2021.105354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/06/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022]
Abstract
Streptococcus suis (S. suis), an important zoonotic pathogenic bacterium, can cause multiple diseases and fatal infections in both humans and animals. The emergence of highly virulent and extensively drug-resistant strains of S. suis has raised questions about the efficacy of available therapeutic agents, thereby necessitating novel therapeutic strategies. Suilysin (SLY) is one of the most essential determinants of virulence for the pathogenicity of S. suis capsular type 2 (SS2). In addition, inhibiting the excessive inflammatory response is a strategy to reduce the damage caused by SS2 infection. In this study, we identified acacetin as an effective inhibitor of SLY, which inhibited the oligomerisation of SLY without affecting bacterial growth. Furthermore, the addition of 4-16 μg/ml acacetin to the co-infection system of the cells reduced S. suis-induced inflammation by downregulating the activation of the MAPK signalling pathway, thereby alleviating the S. suis-mediated cell injury. Thus, in addition to the conventional antibiotic therapy, acacetin represent a potential drug candidate and strategy for the treatment of S. suis infections as it simultaneously inhibited the haemolytic activity of SLY and downregulated the inflammatory response.
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Affiliation(s)
- Shengnan Xie
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yan Zhang
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Lei Xu
- Hospital of Stomatology, Jilin University, Changchun, 130021, China
| | - Shufang Li
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xue Shen
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Li Li
- Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xuming Deng
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun, China; Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yonglin Zhou
- Department of Respiratory Medicine, The First Hospital of Jilin University, Changchun, China; Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China.
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Cieślik M, Bagińska N, Jończyk-Matysiak E, Węgrzyn A, Węgrzyn G, Górski A. Temperate Bacteriophages-The Powerful Indirect Modulators of Eukaryotic Cells and Immune Functions. Viruses 2021; 13:v13061013. [PMID: 34071422 PMCID: PMC8228536 DOI: 10.3390/v13061013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/22/2021] [Accepted: 05/27/2021] [Indexed: 12/11/2022] Open
Abstract
Bacteriophages are natural biological entities that limit the growth and amplification of bacteria. They are important stimulators of evolutionary variability in bacteria, and currently are considered a weapon against antibiotic resistance of bacteria. Nevertheless, apart from their antibacterial activity, phages may act as modulators of mammalian immune responses. In this paper, we focus on temperate phages able to execute the lysogenic development, which may shape animal or human immune response by influencing various processes, including phagocytosis of bacterial invaders and immune modulation of mammalian host cells.
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Affiliation(s)
- Martyna Cieślik
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland; (M.C.); (N.B.); (E.J.-M.)
| | - Natalia Bagińska
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland; (M.C.); (N.B.); (E.J.-M.)
| | - Ewa Jończyk-Matysiak
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland; (M.C.); (N.B.); (E.J.-M.)
| | - Alicja Węgrzyn
- Laboratory of Phage Therapy, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Kładki 24, 80-822 Gdańsk, Poland;
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland;
| | - Andrzej Górski
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland; (M.C.); (N.B.); (E.J.-M.)
- Phage Therapy Unit, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland
- Infant Jesus Hospital, The Medical University of Warsaw, 02-006 Warsaw, Poland
- Correspondence:
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Najafi Olya Z, Najar-Peerayeh S, Yadegar A, Bakhshi B. Clonal diversity and genomic characterization of Panton-valentine Leukocidin (PVL)-positive Staphylococcus aureus in Tehran, Iran. BMC Infect Dis 2021; 21:372. [PMID: 33882854 PMCID: PMC8058961 DOI: 10.1186/s12879-021-06060-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 04/08/2021] [Indexed: 11/25/2022] Open
Abstract
Background Some Staphylococcus aureus strains produce Panton-Valentine leukocidin (PVL), a bi-component pore-forming toxin, which causes leukocyte lysis and tissue necrosis. Currently, there is very limited information on the molecular epidemiology of PVL-encoding S. aureus strains in Iran. This study aimed to determine the molecular epidemiology and genetic background of PVL-positive S. aureus clinical strains isolated from Iranian patients. Methods A total of 28 PVL-positive S. aureus strains were detected from 600 S. aureus isolates between February 2015 and March 2018 from different hospitals in Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Molecular genotyping was performed using SCCmec and accessory gene regulator (agr) typing, PVL haplotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Results The highest antibiotic resistance rate was found to be against erythromycin (57.1%), followed by ciprofloxacin (42.8%) and clindamycin (35.7%). Moreover, 19 (67.9%) out of 28 S. aureus isolates were identified as MRSA, including CA-MRSA (14/19, 73.7%) and HA-MRSA (5/19, 26.3%). SCCmec type IVa was detected as the predominant type (10/19, 52.6%), followed by type III (5/19, 26.3%) and type V (4/19, 21.1%). The agr type I was identified as the most common type (14/28, 50%), and H and R haplotype groups were observed at frequencies of 67.9 and 32.1%, respectively. Among H variants, the predominant variant was H2 (78/9%). The isolates encompassed 21 different sequence types (STs), including 16 new STs (ST5147 to ST5162). Based on eBURST analysis, the isolates were clustered into five CCs, including CC30, CC22, CC1, CC8, and CC5 (ST5160), and nine singletons. PFGE typing showed that 24 isolates were clustered into A (4 pulsotypes), B (9 pulsotypes), and C (11 pulsotypes) clusters. Conclusions A high prevalence of PVL-positive CA-MRSA strains was detected in Iran. The majority of PVL-positive isolates were of H (mostly H2) variant, while R variant was harbored by 100% of PVL-positive MRSA strains. Also, CC8, CC22, and CC30 were identified as the dominant clones among PVL-encoding S. aureus strains. This study promotes a better understanding of the molecular epidemiology and evolution of PVL-positive S. aureus strains in Iran.
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Affiliation(s)
- Zahra Najafi Olya
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Ave, Tehran, 14117-13116, Iran
| | - Shahin Najar-Peerayeh
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Ave, Tehran, 14117-13116, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bita Bakhshi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal-Ale-Ahmad Ave, Tehran, 14117-13116, Iran.
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Wang T, Zhang P, Lv H, Deng X, Wang J. A Natural Dietary Flavone Myricetin as an α-Hemolysin Inhibitor for Controlling Staphylococcus aureus Infection. Front Cell Infect Microbiol 2020; 10:330. [PMID: 32793508 PMCID: PMC7390952 DOI: 10.3389/fcimb.2020.00330] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 05/29/2020] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus, an important agent for lethal bacterial infections, can cause a broad spectrum of diseases in various host species. The emergence of multidrug-resistant and highly virulent strains has raised increasing concerns about the novel therapeutic strategies or agents available for treating S. aureus infection. The critical role of Hla, an essential virulence determinant, in the pathogenicity of S. aureus renders this toxin an attractive target for effective therapeutic applications. Here, we have identified myricetin as an effective inhibitor of Hla that simultaneously inhibits Hla production and neutralizes Hla activity without affecting bacterial growth. Myricetin treatment reduced the oligomerization of Hla and Hla-mediated biofilm formation. The addition of myricetin to the coinfection system of host cells and S. aureus significantly decreased cell injury and downregulated the inflammatory response in cells. Furthermore, S. aureus-infected mice that received myricetin showed alleviated tissue damage in the lung. Our results indicated that myricetin inhibits S. aureus virulence by targeting Hla and downregulates the inflammatory response in host cells. Overall, in addition to traditional antibiotics with antibacterial activity, myricetin may represent a potential candidate, and strategy for S. aureus infection.
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Affiliation(s)
- Tingting Wang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, China.,Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Peng Zhang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, China
| | - Hongfa Lv
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xuming Deng
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jianfeng Wang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, China.,Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
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10
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Wollein Waldetoft K, Råberg L, Lood R. Proliferation and benevolence-A framework for dissecting the mechanisms of microbial virulence and health promotion. Evol Appl 2020; 13:879-888. [PMID: 32431740 PMCID: PMC7232753 DOI: 10.1111/eva.12952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 01/14/2020] [Accepted: 03/06/2020] [Indexed: 12/29/2022] Open
Abstract
Key topics in the study of host–microbe interactions—such as the prevention of drug resistance and the exploitation of beneficial effects of bacteria—would benefit from concerted efforts with both mechanistic and evolutionary approaches. But due to differences in intellectual traditions, insights gained in one field rarely benefit the other. Here, we develop a conceptual and analytical framework for the integrated study of host–microbe interactions. This framework partitions the health effects of microbes and the effector molecules they produce into components with different evolutionary implications. It thereby facilitates the prediction of evolutionary responses to inhibition and exploitation of specific molecular mechanisms.
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Affiliation(s)
| | - Lars Råberg
- Department of Biology Lund University Lund Sweden
| | - Rolf Lood
- Division of Infection Medicine Department of Clinical Sciences Lund University Lund Sweden
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11
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Coombs GW, Baines SL, Howden BP, Swenson KM, O’Brien FG. Diversity of bacteriophages encoding Panton-Valentine leukocidin in temporally and geographically related Staphylococcus aureus. PLoS One 2020; 15:e0228676. [PMID: 32040487 PMCID: PMC7010278 DOI: 10.1371/journal.pone.0228676] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 01/21/2020] [Indexed: 01/21/2023] Open
Abstract
Production of the Panton-Valentine leukocidin (PVL) by Staphylococcus aureus is mediated via the genes lukS-PV and lukF-PV which are carried on bacteriophage ϕSa2. PVL is associated with S. aureus strains that cause serious infections and clones of community-associated methicillin-resistant S. aureus (CA-MRSA) that have additionally disseminated widely. In Western Australia (WA) the original CA-MRSA were PVL negative however, between 2005 and 2008, following the introduction of eight international PVL-positive CA-MRSA, PVL-positive WA CA-MRSA were found. There was concern that PVL bacteriophages from the international clones were transferring into the local clones, therefore a comparative study of PVL-carrying ϕSa2 prophage genomes from historic WA PVL-positive S. aureus and representatives of all PVL-positive CA-MRSA isolated in WA between 2005 and 2008 was performed. The prophages were classified into two genera and three PVL bacteriophage groups and had undergone many recombination events during their evolution. Comparative analysis of mosaic regions of selected bacteriophages using the Alignments of bacteriophage genomes (Alpha) aligner revealed novel recombinations and modules. There was heterogeneity in the chromosomal integration sites, the lysogeny regulation regions, the defence and DNA processing modules, the structural and packaging modules and the lukSF-PV genes. One WA CA-MRSA (WA518751) and one international clone (Korean Clone) have probably acquired PVL-carrying ϕSa2 in WA, however these clones did not disseminate in the community. Genetic heterogeneity made it impossible to trace the source of the PVL prophages in the other WA clones. Against this background of PVL prophage diversity, the sequence of one group, the ϕSa2USA/ϕSa2wa-st93 group, was remarkably stable over at least 20 years and associated with the highly virulent USA300 and ST93-IVa CA-MRSA lineages that have disseminated globally.
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Affiliation(s)
- Geoffrey W. Coombs
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Western Australia, Australia
- PathWest Laboratory Medicine—WA, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
- * E-mail:
| | - Sarah L. Baines
- Doherty Applied Microbial Genomics, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria, Australia
| | - Benjamin P. Howden
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria, Australia
| | - Krister M. Swenson
- LIRMM, CNRS-Univ. Montpellier, Montpellier, France
- IBC Institute de Biologie Computationnelle, Montpellier, France
| | - Frances G. O’Brien
- Curtin Health Innovation Research Institute and the School of Pharmacy & Biomedical Sciences, Curtin University, Western Australia, Australia
- Australian Collaborating Centre for Enterococcus and Staphylococcus Species (ACCESS) Typing and Research, School of Veterinary Sciences and Life Sciences, Murdoch University and Curtin University, School of Pharmacy and Biomedical Sciences, Perth, Western Australia, Australia
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12
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Sinha A, Maurice CF. Bacteriophages: Uncharacterized and Dynamic Regulators of the Immune System. Mediators Inflamm 2019; 2019:3730519. [PMID: 31582898 PMCID: PMC6754933 DOI: 10.1155/2019/3730519] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/06/2019] [Indexed: 12/23/2022] Open
Abstract
The human gut is an extremely active immunological site interfacing with the densest microbial community known to colonize the human body, the gut microbiota. Despite tremendous advances in our comprehension of how the gut microbiota is involved in human health and interacts with the mammalian immune system, most studies are incomplete as they typically do not consider bacteriophages. These bacterial viruses are estimated to be as numerous as their bacterial hosts, with tremendous and mostly uncharacterized genetic diversity. In addition, bacteriophages are not passive members of the gut microbiota, as highlighted by the recent evidence for their active involvement in human health. Yet, how bacteriophages interact with their bacterial hosts and the immune system in the human gut remains poorly described. Here, we aim to fill this gap by providing an overview of bacteriophage communities in the gut during human development, detailing recent findings for their bacterial-mediated effects on the immune response and summarizing the latest evidence for direct interactions between them and the immune system. The dramatic increase in antibiotic-resistant bacterial pathogens has spurred a renewed interest in using bacteriophages for therapy, despite the many unknowns about bacteriophages in the human body. Going forward, more studies encompassing the communities of bacteria, bacteriophages, and the immune system in diverse health and disease settings will provide invaluable insight into this dynamic trio essential for human health.
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Affiliation(s)
- Anshul Sinha
- Department of Microbiology & Immunology, McGill University, Montreal, QC, Canada
| | - Corinne F. Maurice
- Department of Microbiology & Immunology, McGill University, Montreal, QC, Canada
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13
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Kolonitsiou F, Papadimitriou-Olivgeris M, Spiliopoulou A, Drougka E, Jelastopulu E, Anastassiou ED, Spiliopoulou I. Methicillin-Resistant Staphylococcus aureus ST80 Induce Lower Cytokine Production by Monocytes as Compared to Other Sequence Types. Front Microbiol 2019; 9:3310. [PMID: 30687287 PMCID: PMC6333658 DOI: 10.3389/fmicb.2018.03310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 12/19/2018] [Indexed: 12/21/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) remains an important cause of nosocomial and community-associated infections due to its ability to produce toxins and evade host's immune responses. The aim of the present study was to investigate the association of monocytes immune response in terms of cytokines produced after inoculation with different MRSA clones. Thirty-one clinical MRSA strains were selected on the basis of clonal types, accessory gene regulator (agr) groups and toxin genes carriage. Isolates were identified as S. aureus by Gram stain, catalase, coagulase production and PCR for nuc gene. The presence of mecA, lukS/lukF-PV (Panton-Valentine Leukocidin) and tst (Toxic Shock Syndrome Toxin-1) genes, as well as, the determination of agr groups was performed by PCR. Clonality was investigated by means of multi-locus sequence typing (MLST). Peripheral blood mononuclear cells were stimulated with live bacterial cells for 45 min at a ratio of 1:10. Cells were incubated for 10 h and supernatants were collected. The levels of Tumor Necrosis Factor alpha (TNFa), IL-1b, IL-8, IL-6, IL-12p40, IL-10, interferon-gamma (IFN-γ) and IL-2, were measured by Human Cytokine Multiplex Immunoassay kit. Thirteen strains were tst and 12 lukS/lukF-PV-positive. Seven strains belonged to ST80 and ST225, five to ST30 and ST239, while the remaining seven isolates were grouped together as "other." Strains belonging to ST80 induced statistically lower levels of TNFa, IL-1b, IL-8, IL-6, IL-10, IFN-γ, and IL-2. PVL-positive strains classified into ST80 clone induced statistically lower concentrations of most cytokines as compared to PVL-positive strains belonging to other clones, tst-positive strains and toxin-negative ones. Strains of agr3 group belonging to ST80 induced statistically lower concentrations of most tested cytokines as compared to agr3 strains not-belonging to ST80, agr2 or agr1. This low induction of immune response by MRSA ST80 cannot be attributed to the presence of neither lukS/lukF-PV nor agr3.
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Affiliation(s)
- Fevronia Kolonitsiou
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece
| | | | | | - Eleanna Drougka
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece
| | - Eleni Jelastopulu
- Department of Public Health, School of Medicine, University of Patras, Patras, Greece
| | | | - Iris Spiliopoulou
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece
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14
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Sonoda S, Yamaguchi T, Aoki K, Ono D, Sato A, Kajiwara C, Kimura S, Akasaka Y, Ishii Y, Miyazaki Y, Inase N, Tateda K. Evidence of latent molecular diversity determining the virulence of community-associated MRSA USA300 clones in mice. IMMUNITY INFLAMMATION AND DISEASE 2018; 6:402-412. [PMID: 30091216 PMCID: PMC6113770 DOI: 10.1002/iid3.234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 01/26/2023]
Abstract
Introduction The USA300 clone of community‐associated MRSA is reported to be hypervirulent and epidemic in the United States. This clone causes a variety of diseases from lethal pneumonia to mild skin infections. We hypothesized that evolutionary diversity may exist among USA300 clones, which may link virulence traits with host responses and mortality rates. Methods USA300 isolates from severe pneumonia (IP) and skin infection (IS) were characterized by pulsed‐field gel electrophoresis (PFGE) and next‐generation sequencing. Their virulence traits and host responses were compared in a lung infection model. Results The two USA300 isolates were found to be identical in genomic analysis. Robust IL‐6 production, aggregation of bacteria, and hemorrhaging were observed in IP‐infected lungs, which were associated with a higher rate of mortality than that observed with strain IS. Few neutrophils were detected in the lungs infected with strain IP, even at high bacterial loads. Massive production of α‐toxin and coagulase were evident during the early phase of IP infection, and robust gene expression of hla (α‐toxin) and lukS‐PV (Panton–Valentine leukocidin), but not coa, agrA, or rnaIII, was confirmed in vitro. Strain IP also induced strong hemolysis in red blood cells. Conclusions The present data demonstrated latent diversity in the virulence of USA300 clones. Unknown regulatory mechanisms, probably involving a host factor(s) as a trigger, may govern the virulence expression and resultant high mortality in certain sub‐clones of USA300.
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Affiliation(s)
- Shiro Sonoda
- The Integrated Pulmonology, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan.,Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Tetsuo Yamaguchi
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Kotaro Aoki
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Daisuke Ono
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Ayami Sato
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan.,Department of Surgery, Toho University Sakura Medical Center, Chiba, 285-8741, Japan
| | - Chiaki Kajiwara
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Soichiro Kimura
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Yoshikiyo Akasaka
- Department of Pathology, Toho University. Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Yoshikazu Ishii
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
| | - Yasunari Miyazaki
- The Integrated Pulmonology, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Naohiko Inase
- The Integrated Pulmonology, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Kazuhiro Tateda
- Department of Microbiology and Infectious Disease, Toho University, Faculty of Medicine, Tokyo, 143-8540, Japan
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15
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Olaniyi RO, Pancotto L, Grimaldi L, Bagnoli F. Deciphering the Pathological Role of Staphylococcal α-Toxin and Panton-Valentine Leukocidin Using a Novel Ex Vivo Human Skin Model. Front Immunol 2018; 9:951. [PMID: 29867940 PMCID: PMC5953321 DOI: 10.3389/fimmu.2018.00951] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/17/2018] [Indexed: 11/13/2022] Open
Abstract
Staphylococcus aureus alpha-toxin and Panton-Valentine leukocidin (PVL) have been reported to play critical roles in different animal models of skin infection. These models, however, do not completely recapitulate the human disease due to the host specificity of these toxins as well as the intrinsic anatomical and immunological differences between animals and humans. Human skin explants represent a valid alternative to animal models for studying skin infections. Herein, we developed a human skin explant wound model to study the pathogenic role of alpha-toxin and PVL; inflammatory responses elicited by these toxins; and the neutralizing ability of antibodies to mitigate skin damage. Different concentrations of alpha-toxin and/PVL were applied to superficial wounds on human skin explants. Treatment with alpha-toxin resulted in high tissue toxicity and loss of skin epithelial integrity. PVL induced a milder but significant toxicity with no loss of skin structural integrity. The combination of both toxins resulted in increased tissue toxicity as compared with the individual toxins alone. Treatment of the skin with these toxins also resulted in a decrease of CD45-positive cells in the epidermis. In addition, both toxins induced the release of pro-inflammatory cytokines and chemokines. Finally, antibodies raised against alpha-toxin were able to mitigate tissue toxicity in a concentration-dependent manner. Results from this study confirm the key role of α-toxin in staphylococcal infection of the human skin and suggest a possible cooperation of the two toxins in tissue pathology.
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Affiliation(s)
| | | | - Luca Grimaldi
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
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16
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Seilie ES, Bubeck Wardenburg J. Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity. Semin Cell Dev Biol 2017; 72:101-116. [PMID: 28445785 DOI: 10.1016/j.semcdb.2017.04.003] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/22/2017] [Accepted: 04/18/2017] [Indexed: 12/20/2022]
Abstract
Staphylococcus aureus is a prominent human pathogen capable of infecting a variety of host species and tissue sites. This versatility stems from the pathogen's ability to secrete diverse host-damaging virulence factors. Among these factors, the S. aureus pore-forming toxins (PFTs) α-toxin and the bicomponent leukocidins, have garnered much attention for their ability to lyse cells at low concentrations and modulate disease severity. Although many of these toxins were discovered nearly a century ago, their host cell specificities have only been elucidated over the past five to six years, starting with the discovery of the eukaryotic receptor for α-toxin and rapidly followed by identification of the leukocidin receptors. The identification of these receptors has revealed the species- and cell type-specificity of toxin binding, and provided insight into non-lytic effects of PFT intoxication that contribute to disease pathogenesis.
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Affiliation(s)
- E Sachiko Seilie
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, United States; Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States
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17
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Is LukS-PV a novel experimental therapy for leukemia? Gene 2016; 600:44-47. [PMID: 27916717 DOI: 10.1016/j.gene.2016.11.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 11/17/2016] [Accepted: 11/30/2016] [Indexed: 12/15/2022]
Abstract
Although the studies on the pathogenesis and prognosis of leukemia have made revolutionary progress, the long-term survival remains unsatisfactory. Alternative techniques are being developed to target leukemia. Several decades after researchers' work, a variety of bacteria toxins are being explored as potential anti-leukemia agents, either to provide direct effects or to deliver therapeutic proteins to leukemia. LukS-PV, a component of Panton-Valentine Leukocidin secreted by S. aureus, has been tested in acute myeloid leukemia as a novel experimental strategy. Further researches about the targeting mechanisms of LukS-PV are required to make it a complete therapeutic approach for leukemia treatment. The function of this article is to provide clinicians and experimentalists with a chronological and comprehensive appraisal of use of LukS-PV as an experimental strategy for leukemia therapy.
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18
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Li X, He S, Li R, Zhou X, Zhang S, Yu M, Ye Y, Wang Y, Huang C, Wu M. Pseudomonas aeruginosa infection augments inflammation through miR-301b repression of c-Myb-mediated immune activation and infiltration. Nat Microbiol 2016; 1:16132. [PMID: 27670114 PMCID: PMC5061341 DOI: 10.1038/nmicrobiol.2016.132] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 07/05/2016] [Indexed: 02/05/2023]
Abstract
microRNAs (miRNAs) play critical roles in various biological processes including cell proliferation, development, and host defense. However, the molecular mechanism for miRNAs in regulating bacterial-induced inflammation remains largely unclear. Here we report that miR-301b augments pro-inflammatory response during pulmonary infection and caffeine (CAF) suppresses miR-301b’s effect and thereby augmenting respiratory immunity. LPS treatment or Pseudomonas aeruginosa infection induces miR-301b expression via a TLR4/MyD88/NF-κB pathway. Importantly, CAF decreases miR-301b expression through negative regulation of the cAMP/PKA/NF-κB axis. Further, c-Myb is identified as a target of miR-301b, which positively modulates anti-inflammatory cytokines IL-4 and TGF-β1, but negatively regulates pro-inflammatory cytokines MIP-1α and IL-17A. Moreover, repression of miR-301b results in increased transcription of c-Myb and elevated levels of neutrophil infiltration, thereby alleviating infectiou symptoms in mice. These findings reveal miR-301b as a new controller of inflammatory response by repressing c-Myb function to inhibit anti-inflammatory response to bacterial infection, representing a novel mechanism for balancing inflammation.
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Affiliation(s)
- Xuefeng Li
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA.,State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Sisi He
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA.,State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Rongpeng Li
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA
| | - Xikun Zhou
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA.,State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Shuang Zhang
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA.,State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Min Yu
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA.,Department of Thoracic Oncology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yan Ye
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA
| | - Yongsheng Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Canhua Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Min Wu
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, North Dakota 58203-9037, USA
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19
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Reyes-Robles T, Torres VJ. Staphylococcus aureus Pore-Forming Toxins. Curr Top Microbiol Immunol 2016; 409:121-144. [PMID: 27406190 DOI: 10.1007/82_2016_16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Staphylococcus aureus (S. aureus) is a formidable foe equipped with an armamentarium of virulence factors to thwart host defenses and establish a successful infection. Among these virulence factors, S. aureus produces several potent secreted proteins that act as cytotoxins, predominant among them the beta-barrel pore-forming toxins. These toxins play several roles in pathogenesis, including disruption of cellular adherens junctions at epithelial barriers, alteration of intracellular signaling events, modulation of host immune responses, and killing of eukaryotic immune and non-immune cells. This chapter provides an updated overview on the S. aureus beta-barrel pore-forming cytotoxins, the identification of toxin receptors on host cells, and their roles in pathogenesis.
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Affiliation(s)
- Tamara Reyes-Robles
- Department of Microbiology, Microbial Pathogenesis Program, New York University School of Medicine, 522 First Avenue, Smilow Research Building, Room 1010, New York, NY, 10016, USA
| | - Victor J Torres
- Department of Microbiology, Microbial Pathogenesis Program, New York University School of Medicine, 522 First Avenue, Smilow Research Building, Room 1010, New York, NY, 10016, USA.
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20
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Yoong P, Torres VJ. Counter inhibition between leukotoxins attenuates Staphylococcus aureus virulence. Nat Commun 2015; 6:8125. [PMID: 26330208 PMCID: PMC4562310 DOI: 10.1038/ncomms9125] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/21/2015] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus subverts host defences by producing a collection of virulence factors including bi-component pore-forming leukotoxins. Despite extensive sequence conservation, each leukotoxin has unique properties, including disparate cellular receptors and species specificities. How these toxins collectively influence S. aureus pathogenesis is unknown. Here we demonstrate that the leukotoxins LukSF-PV and LukED antagonize each other's cytolytic activities on leukocytes and erythrocytes by forming inactive hybrid complexes. Remarkably, LukSF-PV inhibition of LukED haemolytic activity on both human and murine erythrocytes prevents the release of nutrients required for in vitro bacterial growth. Using in vivo murine models of infection, we show that LukSF-PV negatively influences S. aureus virulence and colonization by inhibiting LukED. Thus, while S. aureus leukotoxins can certainly injure immune cells, the discovery of leukotoxin antagonism suggests that they may also play a role in reducing S. aureus virulence and maintaining infection without killing the host. Staphylococcus aureus strains produce a family of highly related toxins that puncture the cytoplasmic membrane of susceptible cells. Here, Yoong and Torres show that the toxins can counteract each other in a cell type-dependent manner by forming inactive hybrid complexes, thus modulating S. aureus virulence.
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Affiliation(s)
- Pauline Yoong
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
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21
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The bicomponent pore-forming leucocidins of Staphylococcus aureus. Microbiol Mol Biol Rev 2015; 78:199-230. [PMID: 24847020 DOI: 10.1128/mmbr.00055-13] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The ability to produce water-soluble proteins with the capacity to oligomerize and form pores within cellular lipid bilayers is a trait conserved among nearly all forms of life, including humans, single-celled eukaryotes, and numerous bacterial species. In bacteria, some of the most notable pore-forming molecules are protein toxins that interact with mammalian cell membranes to promote lysis, deliver effectors, and modulate cellular homeostasis. Of the bacterial species capable of producing pore-forming toxic molecules, the Gram-positive pathogen Staphylococcus aureus is one of the most notorious. S. aureus can produce seven different pore-forming protein toxins, all of which are believed to play a unique role in promoting the ability of the organism to cause disease in humans and other mammals. The most diverse of these pore-forming toxins, in terms of both functional activity and global representation within S. aureus clinical isolates, are the bicomponent leucocidins. From the first description of their activity on host immune cells over 100 years ago to the detailed investigations of their biochemical function today, the leucocidins remain at the forefront of S. aureus pathogenesis research initiatives. Study of their mode of action is of immediate interest in the realm of therapeutic agent design as well as for studies of bacterial pathogenesis. This review provides an updated perspective on our understanding of the S. aureus leucocidins and their function, specificity, and potential as therapeutic targets.
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22
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Shan W, Bu S, Zhang C, Zhang S, Ding B, Chang W, Dai Y, Shen J, Ma X. LukS-PV, a component of Panton-Valentine leukocidin, exerts potent activity against acute myeloid leukemia in vitro and in vivo. Int J Biochem Cell Biol 2015; 61:20-8. [DOI: 10.1016/j.biocel.2015.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 12/01/2014] [Accepted: 01/09/2015] [Indexed: 12/25/2022]
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23
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Tawk MY, Zimmermann K, Bossu J, Potrich C, Bourcier T, Dalla Serra M, Poulain B, Prévost G, Jover E. Internalization of staphylococcal leukotoxins that bind and divert the
C
5a receptor is required for intracellular
Ca
2+
mobilization by human neutrophils. Cell Microbiol 2015; 17:1241-57. [DOI: 10.1111/cmi.12434] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/26/2015] [Accepted: 03/01/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Mira Y. Tawk
- Fédération de Médecine Translationnelle de Strasbourg EA7290 Virulence Bactérienne Précoce Institut de Bactériologie et Hôpitaux Universitaires de Strasbourg Université de Strasbourg Strasbourg France
| | - Kiran Zimmermann
- Fédération de Médecine Translationnelle de Strasbourg EA7290 Virulence Bactérienne Précoce Institut de Bactériologie et Hôpitaux Universitaires de Strasbourg Université de Strasbourg Strasbourg France
| | - Jean‐Louis Bossu
- INCI – UPR‐CNRS 3212 Physiologie des réseaux de neurones Strasbourg France
| | - Cristina Potrich
- National Research Council of Italy Institute of Biophysics and Bruno Kessler Foundation Trento Italy
| | - Tristan Bourcier
- Fédération de Médecine Translationnelle de Strasbourg EA7290 Virulence Bactérienne Précoce Institut de Bactériologie et Hôpitaux Universitaires de Strasbourg Université de Strasbourg Strasbourg France
| | - Mauro Dalla Serra
- National Research Council of Italy Institute of Biophysics and Bruno Kessler Foundation Trento Italy
| | - Bernard Poulain
- INCI – UPR‐CNRS 3212 Physiologie des réseaux de neurones Strasbourg France
| | - Gilles Prévost
- Fédération de Médecine Translationnelle de Strasbourg EA7290 Virulence Bactérienne Précoce Institut de Bactériologie et Hôpitaux Universitaires de Strasbourg Université de Strasbourg Strasbourg France
| | - Emmanuel Jover
- Fédération de Médecine Translationnelle de Strasbourg EA7290 Virulence Bactérienne Précoce Institut de Bactériologie et Hôpitaux Universitaires de Strasbourg Université de Strasbourg Strasbourg France
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24
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Bazzi AM, Rabaan AA, Fawarah MM, Al-Tawfiq JA. Prevalence of Panton-Valentine leukocidin-positive methicillin-susceptible Staphylococcus aureus infections in a Saudi Arabian hospital. J Infect Public Health 2015; 8:364-8. [PMID: 25817805 DOI: 10.1016/j.jiph.2015.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 01/10/2015] [Accepted: 01/23/2015] [Indexed: 11/29/2022] Open
Abstract
Panton-Valentine leukocidin (PVL) is a two-component toxin associated with the toxicity and virulence of Staphylococcus aureus. The presence of PVL is well documented in community-acquired methicillin-resistant S. aureus (CA-MRSA) and is observed in methicillin-susceptible S. aureus (MSSA) with variable prevalence. We assessed the prevalence of PVL in a sample of 93 MSSA patients in a healthcare facility in Eastern Saudi Arabia using real-time PCR for lukSF-PV genes. The presence or absence of PVL was correlated with age, gender, hospitalization status, infection site and antibiotic resistance. PVL was detected in 28 (30%) patient samples. PVL was associated with a greater likelihood of resistance to trimethoprim-sulfamethoxazole (a resistance of 39.2% of PVL-positive isolates compared to 6.1% of PVL-negative isolates) (p < 0.0007). These results suggest a significant prevalence of PVL expression in MSSA strains in the study population and call for monitoring of and surveillance programs for PVL status and the selection of appropriate antibiotic treatments.
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Affiliation(s)
- Ali M Bazzi
- Microbiology Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
| | - Ali A Rabaan
- Molecular Diagnnostic Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
| | - Mahmoud M Fawarah
- Microbiology Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
| | - Jaffar A Al-Tawfiq
- Specialty Internal Medicine, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia; Indiana University School of Medicine, IN, USA.
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25
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Spaan AN, Vrieling M, Wallet P, Badiou C, Reyes-Robles T, Ohneck EA, Benito Y, de Haas CJ, Day CJ, Jennings MP, Lina G, Vandenesch F, van Kessel KP, Torres VJ, van Strijp JA, Henry T. The staphylococcal toxins γ-haemolysin AB and CB differentially target phagocytes by employing specific chemokine receptors. Nat Commun 2014; 5:5438. [PMID: 25384670 PMCID: PMC4228697 DOI: 10.1038/ncomms6438] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 10/01/2014] [Indexed: 12/20/2022] Open
Abstract
Evasion of the host phagocyte response by Staphylococcus aureus is crucial to successful infection with the pathogen. γ-haemolysin AB and CB (HlgAB, HlgCB) are bicomponent pore-forming toxins present in almost all human S. aureus isolates. Cellular tropism and contribution of the toxins to S. aureus pathophysiology are poorly understood. Here we identify the chemokine receptors CXCR1, CXCR2 and CCR2 as targets for HlgAB, and the complement receptors C5aR and C5L2 as targets for HlgCB. The receptor expression patterns allow the toxins to efficiently and differentially target phagocytic cells. Murine neutrophils are resistant to HlgAB and HlgCB. CCR2 is the sole murine receptor orthologue compatible with γ-haemolysin. In a murine peritonitis model, HlgAB contributes to S. aureus bacteremia in a CCR2-dependent manner. HlgAB-mediated targeting of CCR2(+) cells highlights the involvement of inflammatory macrophages during S. aureus infection. Functional quantification identifies HlgAB and HlgCB as major secreted staphylococcal leukocidins.
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MESH Headings
- Animals
- Bacterial Proteins/physiology
- Bacterial Toxins
- Cells, Cultured
- Disease Models, Animal
- Female
- Hemolysin Proteins/physiology
- Humans
- Macrophages/microbiology
- Macrophages/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Peritonitis/microbiology
- Peritonitis/pathology
- Peritonitis/physiopathology
- Phagocytes/microbiology
- Phagocytes/pathology
- Receptors, CCR2/deficiency
- Receptors, CCR2/genetics
- Receptors, CCR2/physiology
- Receptors, Chemokine/physiology
- Receptors, Complement/physiology
- Receptors, Interleukin-8A/physiology
- Receptors, Interleukin-8B/physiology
- Staphylococcal Infections/pathology
- Staphylococcal Infections/physiopathology
- Staphylococcus aureus
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Affiliation(s)
- András N. Spaan
- Department of Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
| | - Manouk Vrieling
- Department of Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Pierre Wallet
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
- CNRS, UMR5308, 69007 Lyon, France
| | - Cédric Badiou
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
- CNRS, UMR5308, 69007 Lyon, France
| | - Tamara Reyes-Robles
- Department of Microbiology, New York University School of Medicine, 10016 New York, USA
| | - Elizabeth A. Ohneck
- Department of Microbiology, New York University School of Medicine, 10016 New York, USA
| | - Yvonne Benito
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
- CNRS, UMR5308, 69007 Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, 69007 Lyon, France
| | - Carla J.C. de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Christopher J. Day
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland 4222, Australia
| | - Gérard Lina
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
- CNRS, UMR5308, 69007 Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, 69007 Lyon, France
| | - François Vandenesch
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
- CNRS, UMR5308, 69007 Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, 69007 Lyon, France
| | - Kok P.M. van Kessel
- Department of Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Victor J. Torres
- Department of Microbiology, New York University School of Medicine, 10016 New York, USA
| | - Jos A.G. van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Thomas Henry
- CIRI, International Center for Infectiology Research, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France
- Inserm, U1111, 69007 Lyon, France
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26
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Rose HR, Holzman RS, Altman DR, Smyth DS, Wasserman GA, Kafer JM, Wible M, Mendes RE, Torres VJ, Shopsin B. Cytotoxic Virulence Predicts Mortality in Nosocomial Pneumonia Due to Methicillin-Resistant Staphylococcus aureus. J Infect Dis 2014; 211:1862-74. [PMID: 25298028 DOI: 10.1093/infdis/jiu554] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/20/2014] [Indexed: 12/21/2022] Open
Abstract
The current study identified bacterial factors that may improve management of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia. Isolates were obtained from 386 patients enrolled in a randomized, controlled study of antibiotic efficacy. Isolates were screened for production of virulence factors and for vancomycin susceptibility. After adjustment for host factors such as severity of illness and treatment modality, cytotoxic activity was strongly and inversely associated with mortality; however, it had no effect on clinical cure. Isolates having low cytotoxicity, which were derived largely from healthcare-associated clones, exhibited a greater prevalence of vancomycin heteroresistance, and they were recovered more often from patients who were older and frailer. Additionally, a clone with low cytotoxic activity was associated with death and poor clinical improvement. Clone specificity and attenuated virulence appear to be associated with outcome. To our knowledge, these are the first correlations between MRSA virulence and mortality in nosocomial pneumonia.
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Affiliation(s)
- Hannah R Rose
- Division of Infectious Diseases, Department of Medicine
| | | | - Deena R Altman
- Division of Infectious Diseases, Department of Medicine, The Icahn School of Medicine at Mount Sinai, New York, New York
| | | | | | - Jared M Kafer
- Division of Infectious Diseases, Department of Medicine
| | | | | | | | - Bo Shopsin
- Division of Infectious Diseases, Department of Medicine
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27
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Chen J, Yoong P, Ram G, Torres VJ, Novick RP. Single-copy vectors for integration at the SaPI1 attachment site for Staphylococcus aureus. Plasmid 2014; 76:1-7. [PMID: 25192956 DOI: 10.1016/j.plasmid.2014.08.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/15/2014] [Accepted: 08/17/2014] [Indexed: 10/24/2022]
Abstract
We have previously reported the construction of Staphylococcus aureus integration vectors based on the staphylococcal pathogenicity island 1 (SaPI1) site-specific recombination system. These are shuttle vectors that can be propagated in Escherichia coli, which allows for standard DNA manipulations. In S. aureus, these vectors are temperature-sensitive and can only be maintained at non-permissive (42 °C) temperatures by integrating into the chromosome. However, most S. aureus strains are sensitive to prolonged incubations at higher temperatures and will rapidly accumulate mutations, making the use of temperature-sensitive integration vectors impractical for single-copy applications. Here we describe improved versions of these vectors, which are maintained only in single-copy at the SaPI1 attachment site. In addition, we introduce several additional cassettes containing resistance markers, expanding the versatility of integrant selection, especially in strains that are resistant to multiple antibiotics.
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Affiliation(s)
- John Chen
- Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, New York University Medical Center, New York, NY 10016, USA.
| | - Pauline Yoong
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Geeta Ram
- Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, New York University Medical Center, New York, NY 10016, USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Richard P Novick
- Skirball Institute Program in Molecular Pathogenesis and Departments of Microbiology and Medicine, New York University Medical Center, New York, NY 10016, USA.
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28
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Cheung GYC, Kretschmer D, Duong AC, Yeh AJ, Ho TV, Chen Y, Joo HS, Kreiswirth BN, Peschel A, Otto M. Production of an attenuated phenol-soluble modulin variant unique to the MRSA clonal complex 30 increases severity of bloodstream infection. PLoS Pathog 2014; 10:e1004298. [PMID: 25144687 PMCID: PMC4140855 DOI: 10.1371/journal.ppat.1004298] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/20/2014] [Indexed: 12/19/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of morbidity and death. Phenol-soluble modulins (PSMs) are recently-discovered toxins with a key impact on the development of Staphylococcus aureus infections. Allelic variants of PSMs and their potential impact on pathogen success during infection have not yet been described. Here we show that the clonal complex (CC) 30 lineage, a major cause of hospital-associated sepsis and hematogenous complications, expresses an allelic variant of the PSMα3 peptide. We found that this variant, PSMα3N22Y, is characteristic of CC30 strains and has significantly reduced cytolytic and pro-inflammatory potential. Notably, CC30 strains showed reduced cytolytic and chemotactic potential toward human neutrophils, and increased hematogenous seeding in a bacteremia model, compared to strains in which the genome was altered to express non-CC30 PSMα3. Our findings describe a molecular mechanism contributing to attenuated pro-inflammatory potential in a main MRSA lineage. They suggest that reduced pathogen recognition via PSMs allows the bacteria to evade elimination by innate host defenses during bloodstream infections. Furthermore, they underscore the role of point mutations in key S. aureus toxin genes in that adaptation and the pivotal importance PSMs have in defining key S. aureus immune evasion and virulence mechanisms. Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of morbidity and mortality and a great concern for public health. The CC30 MRSA lineage is especially notorious for causing bloodstream infections with complications such as seeding into organs. In our study, we show that this lineage produces an attenuated form of a key S. aureus toxin with decreased pro-inflammatory features. Our results suggest that attenuation of this toxin allows the bacteria to evade recognition and subsequent elimination by host defenses, thereby increasing pathogen success during blood infection.
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Affiliation(s)
- Gordon Y. C. Cheung
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dorothee Kretschmer
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Anthony C. Duong
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anthony J. Yeh
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Trung V. Ho
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yan Chen
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
| | - Barry N. Kreiswirth
- Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Andreas Peschel
- Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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29
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Zhou YP, Wilder-Smith A, Hsu LY. The role of international travel in the spread of methicillin-resistant Staphylococcus aureus. J Travel Med 2014; 21:272-81. [PMID: 24894491 DOI: 10.1111/jtm.12133] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/18/2014] [Accepted: 02/19/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Increasing international travel has facilitated the transmission of various multidrug-resistant bacteria-including methicillin-resistant Staphylococcus aureus (MRSA)-across continents. Individuals may acquire MRSA from the community, healthcare facilities, or even from animal exposure. Skin contact with colonized individuals, fomites, or animals during an overseas trip may result in either asymptomatic colonization or subsequent clinically significant MRSA disease. MRSA strains that harbor the Panton-Valentine leucocidin toxin are particularly associated with community transmission and may potentially have enhanced virulence resulting in serious skin and soft tissue infections or even necrotizing pneumonia. More importantly, secondary transmission events upon return from traveling have been documented, leading to potentially detrimental outbreaks within the community or the healthcare setting. We sought to review the existing literature relating to the role of various aspects of travel in the spread of MRSA. Risk factors for acquiring MRSA during travel together with the need for targeted screening of high-risk individuals will also be explored. METHODS Data for this article were identified via PubMed searches using a combination of search terms: "methicillin resistance," "MRSA," "livestock-associated MRSA," "community-associated MRSA," "travel," and "outbreak." The relevant articles were extensively perused to determine secondary sources of data. RESULTS AND CONCLUSIONS Our review of the current literature suggests that international travel plays a significant role in the transmission of MRSA, potentially contributing to the replacement of existing endemic MRSA with fitter and more transmissible strains. Therefore, selective and targeted screening of travelers with risk factors for MRSA colonization may be beneficial. Healthcare professionals and patients should be considered for screening if they were to return from endemic areas, with the former group decolonized before returning to patient care work, in order to reduce the transmission of MRSA to vulnerable patient populations.
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Affiliation(s)
- Yvonne P Zhou
- Department of Pharmacy, Singapore General Hospital, Singapore, Singapore
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30
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Hait J, Tallent S, Melka D, Keys C, Bennett R. Prevalence of enterotoxins and toxin gene profiles of Staphylococcus aureus isolates recovered from a bakery involved in a second staphylococcal food poisoning occurrence. J Appl Microbiol 2014; 117:866-75. [PMID: 24917203 DOI: 10.1111/jam.12571] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 12/14/2022]
Abstract
AIMS The study objective was to characterize and analyse the distribution of enterotoxins and genes encoding enterotoxins in Staphylococcus aureus strains recovered from the 601 environment and ingredient samples obtained during multiple inspections of a bakery implicated in two separate staphylococcal food poisoning incidents. METHODS AND RESULTS Staphylococcus aureus isolates were evaluated using serological assays for identification of classical staphylococcal enterotoxins (SEs) SEA-SEE and polymerase chain reaction for the detection of newly described SE and SE-like enterotoxin genes seg-seu. Pulsed field gel electrophoresis identified thirteen pattern types. During these investigations, a total of 585 environmental swabs and 16 raw ingredient samples were collected by investigators, 85 of which were confirmed to contain Staph. aureus; of those isolates, 95·3% (81/85) harboured enterotoxin genes and 4·7% (4/85) carried newly described SE and SE-like enterotoxin genes in the absence of classical enterotoxins. CONCLUSIONS Our research demonstrates the prevalence and diversity of classical SEs and the probable underestimated impact of nonclassical SE and SE-like enterotoxins role in domestic staphylococcal food poisoning outbreaks. SIGNIFICANCE AND IMPACT OF THE STUDY Given the abundance of SEs and SE-like toxins, these findings illustrate the utilization of PCR for enterotoxin gene identification and its significance in outbreak investigations.
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Affiliation(s)
- J Hait
- Food and Drug Administration, College Park, MD, USA
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31
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Aman MJ, Adhikari RP. Staphylococcal bicomponent pore-forming toxins: targets for prophylaxis and immunotherapy. Toxins (Basel) 2014; 6:950-72. [PMID: 24599233 PMCID: PMC3968370 DOI: 10.3390/toxins6030950] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 01/09/2023] Open
Abstract
Staphylococccus aureus represents one of the most challenging human pathogens as well as a common colonizer of human skin and mucosal surfaces. S. aureus causes a wide range of diseases from skin and soft tissue infection (SSTI) to debilitating and life-threatening conditions such as osteomyelitis, endocarditis, and necrotizing pneumonia. The range of diseases reflects the remarkable diversity of the virulence factors produced by this pathogen, including surface antigens involved in the establishment of infection and a large number of toxins that mediate a vast array of cellular responses. The staphylococcal toxins are generally believed to have evolved to disarm the innate immune system, the first line of defense against this pathogen. This review focuses on recent advances on elucidating the biological functions of S. aureus bicomponent pore-forming toxins (BCPFTs) and their utility as targets for preventive and therapeutic intervention. These toxins are cytolytic to a variety of immune cells, primarily neutrophils, as well as cells with a critical barrier function. The lytic activity of BCPFTs towards immune cells implies a critical role in immune evasion, and a number of epidemiological studies and animal experiments relate these toxins to clinical disease, particularly SSTI and necrotizing pneumonia. Antibody-mediated neutralization of this lytic activity may provide a strategy for development of toxoid-based vaccines or immunotherapeutics for prevention or mitigation of clinical diseases. However, certain BCPFTs have been proposed to act as danger signals that may alert the immune system through an inflammatory response. The utility of a neutralizing vaccination strategy must be weighed against such immune-activating potential.
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Affiliation(s)
- M Javad Aman
- Integrated BioTherapeutics Inc., 21 Firstfield Rd., Gaithersburg, MD 20878, USA.
| | - Rajan P Adhikari
- Integrated BioTherapeutics Inc., 21 Firstfield Rd., Gaithersburg, MD 20878, USA.
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32
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Spaan AN, Henry T, van Rooijen WJM, Perret M, Badiou C, Aerts PC, Kemmink J, de Haas CJC, van Kessel KPM, Vandenesch F, Lina G, van Strijp JAG. The staphylococcal toxin Panton-Valentine Leukocidin targets human C5a receptors. Cell Host Microbe 2013; 13:584-594. [PMID: 23684309 DOI: 10.1016/j.chom.2013.04.006] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/15/2013] [Accepted: 04/09/2013] [Indexed: 12/14/2022]
Abstract
Panton-Valentine Leukocidin (PVL) is a staphylococcal bicomponent pore-forming toxin linked to severe invasive infections. Target-cell and species specificity of PVL are poorly understood, and the mechanism of action of this toxin in Staphylococcus aureus virulence is controversial. Here, we identify the human complement receptors C5aR and C5L2 as host targets of PVL, mediating both toxin binding and cytotoxicity. Expression and interspecies variations of the C5aR determine cell and species specificity of PVL. The C5aR binding PVL component, LukS-PV, is a potent inhibitor of C5a-induced immune cell activation. These findings provide insight into leukocidin function and staphylococcal virulence and offer directions for future investigations into individual susceptibility to severe staphylococcal disease.
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Affiliation(s)
- András N Spaan
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Thomas Henry
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France
| | | | - Magali Perret
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France
| | - Cédric Badiou
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France
| | - Piet C Aerts
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Johan Kemmink
- Medicinal Chemistry and Chemical Biology, Utrecht University, 3584CX Utrecht, The Netherlands
| | - Carla J C de Haas
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Kok P M van Kessel
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - François Vandenesch
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France; Hospices Civils de Lyon, 69007 Lyon, France
| | - Gérard Lina
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France; Hospices Civils de Lyon, 69007 Lyon, France
| | - Jos A G van Strijp
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands.
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33
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Kobayashi SD, Olsen RJ, LaCasse RA, Safronetz D, Ashraf M, Porter AR, Braughton KR, Feldmann F, Clifton DR, Kash JC, Bailey JR, Gardner DJ, Otto M, Brining DL, Kreiswirth BN, Taubenberger JK, Parnell MJ, Feldmann H, Musser JM, DeLeo FR. Seasonal H3N2 influenza A virus fails to enhance Staphylococcus aureus co-infection in a non-human primate respiratory tract infection model. Virulence 2013; 4:707-15. [PMID: 24104465 DOI: 10.4161/viru.26572] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Staphylococcus aureus community-acquired pneumonia is often associated with influenza or an influenza-like syndrome. Morbidity and mortality due to methicillin-resistant S. aureus (MRSA) or influenza and pneumonia, which includes bacterial co-infection, are among the top causes of death by infectious diseases in the United States. We developed a non-lethal influenza A virus (IAV) (H3N2)/S. aureus co-infection model in cynomolgus macaques (Macaca fascicularis) to test the hypothesis that seasonal IAV infection predisposes non-human primates to severe S. aureus pneumonia. Infection and disease progression were monitored by clinical assessment of animal health; analysis of blood chemistry, nasal swabs, and X-rays; and gross pathology and histopathology of lungs from infected animals. Seasonal IAV infection in healthy cynomolgus macaques caused mild pneumonia, but unexpectedly, did not predispose these animals to subsequent severe infection with the community-associated MRSA clone USA300. We conclude that in our co-infection model, seasonal IAV infection alone is not sufficient to promote severe S. aureus pneumonia in otherwise healthy non-human primates. The implication of these findings is that comorbidity factors in addition to IAV infection are required to predispose individuals to secondary S. aureus pneumonia.
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Affiliation(s)
- Scott D Kobayashi
- Laboratory of Human Bacterial Pathogenesis; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Randall J Olsen
- Center for Molecular and Translational Human Infectious Disease Research; The Methodist Hospital Research Institute; Houston, TX USA; Department of Pathology and Genomic Medicine; The Methodist Hospital; Houston, TX USA
| | - Rachel A LaCasse
- Veterinary Branch; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - David Safronetz
- Laboratory of Virology; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Madiha Ashraf
- Center for Molecular and Translational Human Infectious Disease Research; The Methodist Hospital Research Institute; Houston, TX USA; Department of Medicine; The Methodist Hospital; Houston, TX USA
| | - Adeline R Porter
- Laboratory of Human Bacterial Pathogenesis; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Kevin R Braughton
- Laboratory of Human Bacterial Pathogenesis; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Friederike Feldmann
- Office of Operations Management; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Dawn R Clifton
- Laboratory of Virology; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - John C Kash
- Laboratory of Infectious Diseases; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Bethesda, MD USA
| | - John R Bailey
- Veterinary Branch; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Donald J Gardner
- Veterinary Branch; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Michael Otto
- Laboratory of Human Bacterial Pathogenesis; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Douglas L Brining
- Veterinary Branch; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Barry N Kreiswirth
- Public Health Research Institute; University of Medicine and Dentistry of New Jersey; Newark, NJ USA
| | - Jeffrey K Taubenberger
- Laboratory of Infectious Diseases; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Bethesda, MD USA
| | - Michael J Parnell
- Veterinary Branch; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - Heinz Feldmann
- Laboratory of Virology; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
| | - James M Musser
- Center for Molecular and Translational Human Infectious Disease Research; The Methodist Hospital Research Institute; Houston, TX USA; Department of Pathology and Genomic Medicine; The Methodist Hospital; Houston, TX USA
| | - Frank R DeLeo
- Laboratory of Human Bacterial Pathogenesis; Rocky Mountain Laboratories; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Hamilton, MT USA
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Yoong P, Torres VJ. The effects of Staphylococcus aureus leukotoxins on the host: cell lysis and beyond. Curr Opin Microbiol 2013; 16:63-9. [PMID: 23466211 DOI: 10.1016/j.mib.2013.01.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/03/2012] [Accepted: 01/28/2013] [Indexed: 12/24/2022]
Abstract
The success of Staphylococcus aureus as a leading cause of deadly hospital-acquired and community-acquired infections is attributed to its high-level resistance to most antibiotics, and the multitude of virulence factors it elaborates. Most clinical isolates produce up to four bi-component pore-forming toxins capable of lysing cells of the immune system. Subtle differences in activity and target range of each leukotoxin suggest that these toxins are not redundant, but instead may have specialized functions in attacking and/or evading host defenses. In turn, the host has developed countermeasures recognizing sublytic levels of leukotoxins as signals to activate protective immune defenses. The opposing cytotoxic and immune-activating effects of leukotoxins on host cells make for a complex dynamic between S. aureus and the host.
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Affiliation(s)
- Pauline Yoong
- Department of Microbiology, New York University School of Medicine, United States
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Zaidi T, Zaidi T, Yoong P, Pier GB. Staphylococcus aureus corneal infections: effect of the Panton-Valentine leukocidin (PVL) and antibody to PVL on virulence and pathology. Invest Ophthalmol Vis Sci 2013; 54:4430-8. [PMID: 23737477 DOI: 10.1167/iovs.13-11701] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Community-associated methicillin-resistant Staphylococcus aureus strains expressing Panton-Valentine leukocidin (PVL) are associated with severe skin and soft tissue infections, necrotizing pneumonia, and eye infections. We determined PVL's toxicity on infected mouse and cultured human corneal epithelial cells and the role of PVL and antibody to PVL in pathogenesis of murine keratitis. METHODS Cytotoxicity on corneas and corneal epithelial cells was evaluated by LDH assays. Scratched corneas of female A/J mice were inoculated with approximately 10⁷ CFU/eye of either WT S. aureus, isogenic ΔPVL, or strains overproducing PVL. Antibodies to PVL or control sera were topically applied to infected corneas 0, 24, and 32 hours postinfection, corneas scored for pathology and tissue levels of S. aureus were determined. RESULTS PVL expression augmented the cytotoxicity of S. aureus on infected mouse corneas and human cultured corneal epithelial cells. Variable effects on leukocyte recruitment, pathogenesis, and immunity were obtained in the in vivo studies. Inactivation of PVL in USA300 strains caused reduced pathology and bacterial counts. Results were variable when comparing WT and ΔPVL USA400 strains, while USA400 strains overproducing PVL caused increased bacterial burdens. Topical treatment with polyclonal antibody to PVL yielded significant reductions in corneal pathology and bacterial CFU in corneas infected with USA300 strains, whereas effects were inconsistent in eyes infected with USA400 strains. CONCLUSIONS PVL enhanced the virulence of a subset of MRSA strains in a keratitis model. Coupled with a variable effect of antibody treatment, it appears that PVL plays an inconsistent role in pathogenesis and immunity to S. aureus corneal infection.
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Affiliation(s)
- Tanweer Zaidi
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Abstract
Developing a universal vaccine for S. aureus is a top priority but to date we have only had failures in human clinical trials. Given the plethora of bacterial virulence factors, broad range of the health of humans at-risk for infections, lack of any information regarding immune effectors mediating protection for any manifestation of S. aureus infection and overall competence of this organism as a colonizer, commensal and pathogen, we may just simply have to accept the fact that we will not get a universal vaccine. Antigenic variation is a major challenge for some vaccine targets and for many conserved targets the organism can easily decrease or even eliminate expression to avoid immune effectors without compromise to infectivity and ability to cause disease. Studies of human immune responses similarly have been unable to identify any clear mediators of immunity and data from such studies can only eliminate those found not to be associated with protection or that might serve as a marker for individuals with a higher level of resistance to infection. Animal studies are not predictive of success in humans and unlikely will be except in hindsight if and when we develop an efficacious vaccine. Successful vaccines for other bacteria based on capsular polysaccharides have not worked to date for S. aureus, and laboratory studies combining antibody to the major capsular serotypes and the other S. aureus surface polysaccharide, poly-N-acetyl glucosamine, unexpectedly showed interference not augmentation of immunity. Potential pathways toward vaccine development do exist but for the foreseeable future will be based on empiric approaches derived from laboratory-based in vitro and animal tests and not on inducing a known immune effector that predicts human resistance to infection.
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Affiliation(s)
- Gerald B Pier
- Division of Infectious Diseases; Department of Medicine; Brigham and Women's Hospital; Harvard Medical School; Boston, MA USA
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Staphylococcus aureus LukAB cytotoxin kills human neutrophils by targeting the CD11b subunit of the integrin Mac-1. Proc Natl Acad Sci U S A 2013; 110:10794-9. [PMID: 23754403 DOI: 10.1073/pnas.1305121110] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Staphylococcus aureus causes diseases ranging from superficial wound infections to more invasive manifestations like osteomyelitis and endocarditis. The evasion of host phagocytes recruited to the site of infection is essential to the success of S. aureus as a pathogen. A single S. aureus strain can produce up to five different bicomponent pore-forming leukotoxins that lyse immune cells by forming pores in the cellular plasma membrane. Although these leukotoxins have been considered redundant due to their cytotoxic activity toward human neutrophils, each toxin displays varied species and cell-type specificities. This suggests that cellular factors may influence which cells each toxin targets. Here we describe the identification of CD11b, the α subunit of the αM/β2 integrin (CD11b/CD18), macrophage-1 antigen, or complement receptor 3, as a cellular receptor for leukocidin A/B (LukAB), an important toxin that contributes to S. aureus killing of human neutrophils. We demonstrate that CD11b renders human neutrophils susceptible to LukAB-mediated killing by purified LukAB as well as during S. aureus infection ex vivo. LukAB directly interacts with human CD11b by binding to the I domain, a property that determines the species specificity exhibited by this toxin. Identification of a LukAB cellular target has broad implications for the use of animal models to study the role of LukAB in S. aureus pathogenesis, explains the toxin's tropism toward human neutrophils and other phagocytes, and provides a cellular therapeutic target to block the effect of LukAB toward human neutrophils.
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Uhlemann AC, Kennedy AD, Martens C, Porcella SF, Deleo FR, Lowy FD. Toward an understanding of the evolution of Staphylococcus aureus strain USA300 during colonization in community households. Genome Biol Evol 2013; 4:1275-85. [PMID: 23104992 PMCID: PMC3542572 DOI: 10.1093/gbe/evs094] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus is a frequent cause of serious infections and also a human commensal. The emergence of community-associated methicillin-resistant S. aureus led to a dramatic increase in skin and soft tissue infections worldwide. This epidemic has been driven by a limited number of clones, such as USA300 in the United States. To better understand the extent of USA300 evolution and diversification within communities, we performed comparative whole-genome sequencing of three clinical and five colonizing USA300 isolates collected longitudinally from three unrelated households over a 15-month period. Phylogenetic analysis that incorporated additional geographically diverse USA300 isolates indicated that all but one likely arose from a common recent ancestor. Although limited genetic adaptation occurred over the study period, the greatest genetic heterogeneity occurred between isolates from different households and within one heavily colonized household. This diversity allowed for a more accurate tracking of interpersonal USA300 transmission. Sequencing of persisting USA300 isolates revealed mutations in genes involved in major aspects of S. aureus function: adhesion, cell wall biosynthesis, virulence, and carbohydrate metabolism. Genetic variations also included accumulation of multiple polymorphisms within select genes of two multigene operons, suggestive of small genome rearrangements rather than de novo single point mutations. Such rearrangements have been underappreciated in S. aureus and may represent novel means of strain variation. Subtle genetic changes may contribute to USA300 fitness and persistence. Elucidation of small genome rearrangements reveals a potentially new and intriguing mechanism of directed S. aureus genome diversification in environmental niches and during pathogen-host interactions.
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Affiliation(s)
- Anne-Catrin Uhlemann
- Division of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians & Surgeons, New York, NY, USA.
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Prabhakara S, Khedkar S, Shambat SM, Srinivasan R, Basu A, Norrby-Teglund A, Seshasayee ASN, Arakere G. Genome sequencing unveils a novel sea enterotoxin-carrying PVL phage in Staphylococcus aureus ST772 from India. PLoS One 2013; 8:e60013. [PMID: 23544121 PMCID: PMC3609733 DOI: 10.1371/journal.pone.0060013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 02/20/2013] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen, first recognized as a leading cause of hospital-acquired infections. Community-associated S. aureus (CA-SA) pose a greater threat due to increase in severity of infection and disease among children and healthy adults. CA-SA strains in India are genetically diverse, among which is the sequence type (ST) 772, which has now spread to Australia, Europe and Japan. Towards understanding the genetic characteristics of ST772, we obtained draft genome sequences of five relevant clinical isolates and studied the properties of their PVL-carrying prophages, whose presence is a defining hallmark of CA-SA. We show that this is a novel prophage, which carries the structural genes of the hlb-carrying prophage and includes the sea enterotoxin. This architecture probably emerged early within the ST772 lineage, at least in India. The sea gene, unique to ST772 PVL, despite having promoter sequence characteristics typical of low expression, appears to be highly expressed during early phase of growth in laboratory conditions. We speculate that this might be a consequence of its novel sequence context. The crippled nature of the hlb-converting prophage in ST772 suggests that widespread mobility of the sea enterotoxin might be a selective force behind its 'transfer' to the PVL prophage. Wild type ST772 strains induced strong proliferative responses as well as high cytotoxic activity against neutrophils, likely mediated by superantigen SEA and the PVL toxin respectively. Both proliferation and cytotoxicity were markedly reduced in a cured ST772 strain indicating the impact of the phage on virulence. The presence of SEA alongside the genes for the immune system-modulating PVL toxin may contribute to the success and virulence of ST772.
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Affiliation(s)
- Sushma Prabhakara
- Society for Innovation and Development, Indian Institute of Science, Bengaluru, India
| | - Supriya Khedkar
- National Centre for Biological Sciences, TIFR, GKVK, Bengaluru, India
| | - Srikanth Mairpady Shambat
- Karolinska Institute, Center for Infectious Medicine F59, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | | | - Atanu Basu
- National Institute of Virology, Pune, India
| | - Anna Norrby-Teglund
- Karolinska Institute, Center for Infectious Medicine F59, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | | | - Gayathri Arakere
- Society for Innovation and Development, Indian Institute of Science, Bengaluru, India
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Bacterial survival amidst an immune onslaught: the contribution of the Staphylococcus aureus leukotoxins. PLoS Pathog 2013; 9:e1003143. [PMID: 23436994 PMCID: PMC3578777 DOI: 10.1371/journal.ppat.1003143] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Ben-Ami R, Watson CC, Lewis RE, Albert ND, Arias CA, Raad II, Kontoyiannis DP. Drosophila melanogaster as a model to explore the effects of methicillin-resistant Staphylococcus aureus strain type on virulence and response to linezolid treatment. Microb Pathog 2012; 55:16-20. [PMID: 23232438 DOI: 10.1016/j.micpath.2012.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 11/25/2012] [Accepted: 11/30/2012] [Indexed: 11/24/2022]
Abstract
BACKGROUND USA300 is a uniquely successful methicillin-resistant Staphylococcus aureus (MRSA) clone that has been associated with Panton-Valentine leukocidin (PVL) production and severe infections. However, conflicting experimental and epidemiological data exist regarding the virulence of USA300 relative to other MRSA clones. We aimed to address this issue using Drosophila melanogaster as a model host to study strain and PVL-dependent variations in virulence among MRSA clinical isolates. RESULTS We studied the relative virulence of 39 MRSA isolates: 17 (43%) were PFGE type USA300. Lethal MRSA infection was reproducibly induced both in wild-type (WT) and Toll-deficient D. melanogaster. USA300 strains had significantly lower lethality than non-USA300 strains in a WT background but not in Toll-deficient flies. PFGE type (USA300 versus non-USA300) and PVL status did not affect the response to treatment with linezolid. Virulence was similar in strains with high vancomycin MIC (≥2 μg/mL) versus those with vancomycin MIC<2 μg/mL. CONCLUSIONS D. melanogaster is a potentially useful model host to study pathogenicity and response to antibiotic treatment in S. aureus. Our results imply that the attenuated virulence of PVL(+)/USA300 requires intact host innate immunity.
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Affiliation(s)
- Ronen Ben-Ami
- Infectious Diseases Unit, Tel Aviv Medical Center, Israel.
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