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Alsolami A, ALGhasab NS, Alharbi MSM, Bashir AI, Saleem M, Syed Khaja AS, Aldakheel DF, Rakha E, Alshammari JA, Taha TE, Melibari Z, Alharbi YH, Almutlag AA, Said KB. Community-Acquired Methicillin-Resistant Staphylococcus aureus in Hospitals: Age-Specificity and Potential Zoonotic-Zooanthroponotic Transmission Dynamics. Diagnostics (Basel) 2023; 13:2089. [PMID: 37370983 DOI: 10.3390/diagnostics13122089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 05/29/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) lineages are a devastating clinical and public health issue. Data on local lineage profiles are limited. We report on the frequency of community-acquired and hospital-acquired cases (CA-MRSA, HA-MRSA). We studied 147 isolates from King Khalid tertiary care hospitals (KKH), each from a case in a patient and including 33 patients at the Maternity and Children's Hospital (MCH). Of the 147 isolates, 87 males (59%) and 60 females (41%) were in KKH. The overwhelming majority (80%; n = 119/147) were CA-MRSA in KKH. Intriguingly, despite significant differences between males (70%) and females (53%), lineage-acquisition remained age-specific around 58-60 years in both genders. However, while CA-MRSA dominated early in life (0-20, 70% MCH), it increased with age in KKH adults; 21-50 (28%), >50 (59%) until the overall 80% (n = 144/180). Major specimens included skin-wounds, surgeries (70.3%), blood (13.5%), sputum (8.8%), very rarely urine (4.1%), and nasal (3.4%), albeit most patients showed severe enteritis and necrotizing pneumonia. Antibiograms showed high beta lactam resistances, including amoxicillin-clavulanate (83%), oxacillin (84%), cefoxitin FOX (100%), penicillin and ampicillin (~100%), as well as high resistance (82%) to carbapenem. Fortunately, high susceptibility was seen to non-beta lactams and, to a lesser extent, gentamicin, erythromycin, and fusidic acid; 33%, 34%, and 38%, respectively, in KKH. A similar pattern was seen in MCH except for a low resistance pattern to gentamicin CN, clindamycin CD, erythromycin E, and tobramycin TOB; 34%, 31%, 39%, and 41%, respectively, except for fusidic acid. These findings have significant clinical implications for MRSA patient management strategies. Clinical- and lineage-profiles imply host-selection and zoonotic-zooanthroponotic transmission dynamics. Future molecular typing, sequencing, and characterization of dominant clone(s) is imperative.
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Affiliation(s)
- Ahmed Alsolami
- Department of Internal Medicine, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Naif Saad ALGhasab
- Department of Cardiology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Mohammed S M Alharbi
- Department of Internal Medicine, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Abdelhafiz I Bashir
- Department of Physiology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Mohd Saleem
- Department of Pathology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | | | - Dakheel F Aldakheel
- Medical Coordination Unit, Ha'il General Hospital, Ha'il 55428, Saudi Arabia
| | - Ehab Rakha
- Departments of Microbiology, King Khalid Hospital, Ha'il 55421, Saudi Arabia
- Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Jabar Aziz Alshammari
- Department of Pathology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Taha E Taha
- Department of Epidemiology, John Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Ziyad Melibari
- Department of Pathology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Yaseer H Alharbi
- Department of Pathology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Ali A Almutlag
- Department of Pathology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
| | - Kamaleldin B Said
- Department of Pathology, College of Medicine, University of Ha'il, Ha'il 55476, Saudi Arabia
- Genomics, Bioinformatics and Systems Biology, Carleton University, 1125 Colonel-By Drive, Ottawa, ON K1S 5B6, Canada
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Jesus C, Soares R, Cunha E, Grilo M, Tavares L, Oliveira M. Influence of Nisin-Biogel at Subinhibitory Concentrations on Virulence Expression in Staphylococcus aureus Isolates from Diabetic Foot Infections. Antibiotics (Basel) 2021; 10:antibiotics10121501. [PMID: 34943712 PMCID: PMC8698857 DOI: 10.3390/antibiotics10121501] [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: 11/07/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 01/22/2023] Open
Abstract
A new approach to diabetic foot infections (DFIs) has been investigated, using a nisin-biogel combining the antimicrobial peptide (AMP) nisin with the natural polysaccharide guar-gum. Since in in vivo conditions bacteria may be exposed to decreased antimicrobial concentrations, known as subinhibitory concentrations (sub-MICs), effects of nisin-biogel sub-MIC values corresponding to 1/2, 1/4 and 1/8 of nisin's minimum inhibitory concentration (MIC) on virulence expression by six Staphylococcus aureus DFI isolates was evaluated by determining bacteria growth rate; expression of genes encoding for staphylococcal protein A (spA), coagulase (coa), clumping factor A (clfA), autolysin (atl), intracellular adhesin A (icaA), intracellular adhesin D (icaD), and the accessory gene regulator I (agrI); biofilm formation; Coa production; and SpA release. Nisin-biogel sub-MICs decreased bacterial growth in a strain- and dose-dependent manner, decreased agrI, atl and clfA expression, and increased spA, coa, icaA and icaD expression. Biofilm formation increased in the presence of nisin-biogel at 1/4 and 1/8 MIC, whereas 1/2 MIC had no effect. Finally, nisin-biogel at sub-MICs did not affect coagulase production, but decreased SpA production in a dose-dependent manner. Results highlight the importance of optimizing nisin-biogel doses before proceeding to in vivo trials, to reduce the risk of virulence factor's up-regulation due to the presence of inappropriate antimicrobial concentrations.
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Bastos LR, Martins MCF, Albano RM, Marques EA, Leão RS. Whole genome sequencing of a ST2594 MRSA strain causing non-mucosal preoperative colonization and low-grade postoperative infection. Antonie van Leeuwenhoek 2019; 112:961-964. [PMID: 30663019 DOI: 10.1007/s10482-019-01229-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 01/09/2019] [Indexed: 10/27/2022]
Abstract
We present a post-operative infection caused by a methicillin-resistant Staphylococcus aureus strain, previously isolated in the preoperative screening, in a patient submitted to femoral osteosynthesis, successfully treated with oral ciprofloxacin. The isolate exhibited in vitro resistance to ciprofloxacin, Staphylococcal Cassette Chromosome mec type IV, it was negative for the lukS-PV Panton-Valentine leucocidin gene and belonged to ST2594 in multilocus sequence typing analysis. Whole genome sequencing revealed a genome size of 2,818,289 base pairs. The annotated genomes of ST2594 and N315 strains were compared, looking for genes related to virulence and resistance. The lack of the tst, sec, sel genes, associated with a mutation in the clfA gene, may partially explain the low morbity in this case.
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Affiliation(s)
- Leonardo Ribeiro Bastos
- Department of Microbiology, Immunology and Parasitology, Medical Science School, State University of Rio de Janeiro, Avenida 28 de Setembro, 87, fundos, 3º andar, Rio de Janeiro, RJ, CEP: 20551-030, Brazil
| | | | - Rodolpho Mattos Albano
- Biochemistry Department, Institute of Biology Roberto Alcântara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elizabeth Andrade Marques
- Department of Microbiology, Immunology and Parasitology, Medical Science School, State University of Rio de Janeiro, Avenida 28 de Setembro, 87, fundos, 3º andar, Rio de Janeiro, RJ, CEP: 20551-030, Brazil
| | - Robson Souza Leão
- Department of Microbiology, Immunology and Parasitology, Medical Science School, State University of Rio de Janeiro, Avenida 28 de Setembro, 87, fundos, 3º andar, Rio de Janeiro, RJ, CEP: 20551-030, Brazil.
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Colavite PM, Ishikawa LLW, Zorzella-Pezavento SFG, Oliveira LRCD, França TGD, da Rosa LC, Chiuso-Minicucci F, Vieira AE, Francisconi CF, da Cunha MDLRDS, Garlet GP, Sartori A. Cloxacillin control of experimental arthritis induced by SEC(+) Staphylococcus aureus is associated with downmodulation of local and systemic cytokines. Cell Microbiol 2015; 18:998-1008. [PMID: 26695535 DOI: 10.1111/cmi.12563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 11/23/2015] [Accepted: 12/17/2015] [Indexed: 01/20/2023]
Abstract
Staphylococcus aureus is the most common agent of septic arthritis (SA) that is a severe, rapidly progressive and erosive disease. In this work we investigated the clinical, histopathological and immunological characteristics of the SA triggered by an enterotoxin C producer S. aureus strain. The effect of a β-lactamic antibiotic over disease evolution and cytokine production was also evaluated. After confirmation that ATCC 19095 SEC(+) strain preserved its ability to produce enterotoxin C, this bacteria was used to infect C57BL/6 male mice. Body weight, clinical score and disease prevalence were daily evaluated during 14 days. Cytokine production by splenocytes, cytokine mRNA expression in arthritic lesions, transcription factors mRNA expression in inguinal lymph nodes and histopathological analysis were performed 7 and 14 days after infection. ATCC 19095 SEC(+) strain caused a severe arthritis characterized by weight loss, high clinical scores and a 100% disease prevalence. Histopathological analysis revealed inflammation, pannus formation and bone erosion. Arthritis aggravation was associated with elevated production of pro-inflammatory cytokines, higher local mRNA expression of these cytokines and also higher mRNA expression of T-bet, ROR-γ and GATA-3. Disease control by cloxacillin was associated with decreased production of pro-inflammatory cytokines but not of IL-10. These findings indicate that the ATCC 19095 SEC(+) strain is able to initiate a severe septic arthritis in mice associated with elevated cytokine production that can be, however, controlled by cloxacillin.
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Affiliation(s)
- Priscila Maria Colavite
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Larissa Lumi Watanabe Ishikawa
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | | | - Larissa Ragozo Cardoso de Oliveira
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Thaís Graziela Donegá França
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Larissa Camargo da Rosa
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Fernanda Chiuso-Minicucci
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Andreia Espíndola Vieira
- Department of Biological Sciences, School of Dentistry of Bauru, São Paulo University-FOB/USP, Bauru, São Paulo, Brazil
| | - Carolina Fávaro Francisconi
- Department of Biological Sciences, School of Dentistry of Bauru, São Paulo University-FOB/USP, Bauru, São Paulo, Brazil
| | | | - Gustavo Pompermaier Garlet
- Department of Biological Sciences, School of Dentistry of Bauru, São Paulo University-FOB/USP, Bauru, São Paulo, Brazil
| | - Alexandrina Sartori
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
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Hansenová Maňásková S, Nazmi K, van Belkum A, Bikker FJ, van Wamel WJB, Veerman ECI. Synthetic LPETG-containing peptide incorporation in the Staphylococcus aureus cell-wall in a sortase A- and growth phase-dependent manner. PLoS One 2014; 9:e89260. [PMID: 24586638 PMCID: PMC3929722 DOI: 10.1371/journal.pone.0089260] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/16/2014] [Indexed: 11/18/2022] Open
Abstract
The majority of Staphylococcus aureus virulence- and colonization-associated surface proteins contain a pentapeptide recognition motif (LPXTG). This motif can be recognized and cleaved by sortase A (SrtA) which is a membrane-bound transpeptidase. After cleavage these proteins are covalently incorporated into the peptidoglycan. Therefore, SrtA plays a key role in S. aureus virulence. We aimed to generate a substrate mimicking this SrtA recognition motif for several purposes: to incorporate this substrate into the S. aureus cell-wall in a SrtA-dependent manner, to characterize this incorporation and to determine the effect of substrate incorporation on the incorporation of native SrtA-dependent cell-surface-associated proteins. We synthesized substrate containing the specific LPXTG motif, LPETG. As a negative control we used a scrambled version of this substrate, EGTLP and a S. aureus srtA knockout strain. Both substrates contained a fluorescence label for detection by FACScan and fluorescence microscope. A spreading assay and a competitive Luminex assay were used to determine the effect of substrate treatment on native LPXTG containing proteins deposition in the bacterial cell-wall. We demonstrate a SrtA-dependent covalent incorporation of the LPETG-containing substrate in wild type S. aureus strains and several other Gram-positive bacterial species. LPETG-containing substrate incorporation in S. aureus was growth phase-dependent and peaked at the stationary phase. This incorporation negatively correlated with srtA mRNA expression. Exogenous addition of the artificial substrate did not result in a decreased expression of native SrtA substrates (e.g. clumping factor A/B and protein A) nor induced a srtA knockout phenotype.
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Affiliation(s)
- Silvie Hansenová Maňásková
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
- * E-mail:
| | - Kamran Nazmi
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands
| | - Alex van Belkum
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Floris J. Bikker
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands
| | - Willem J. B. van Wamel
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Enno C. I. Veerman
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands
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Kenny JG, Moran J, Kolar SL, Ulanov A, Li Z, Shaw LN, Josefsson E, Horsburgh MJ. Mannitol utilisation is required for protection of Staphylococcus aureus from human skin antimicrobial fatty acids. PLoS One 2013; 8:e67698. [PMID: 23861785 PMCID: PMC3701532 DOI: 10.1371/journal.pone.0067698] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 05/21/2013] [Indexed: 11/30/2022] Open
Abstract
Mannitol (Mtl) fermentation, with the subsequent production of acid, is a species signature of Staphylococcus aureus, and discriminates it from most other members of the genus. Inactivation of the gene mtlD, encoding Mtl-1-P dehydrogenase was found to markedly reduce survival in the presence of the antimicrobial fatty acid, linoleic acid. We demonstrate that the sugar alcohol has a potentiating action for this membrane-acting antimicrobial. Analysis of cellular metabolites revealed that, during exponential growth, the mtlD mutant accumulated high levels of Mtl and Mtl-P. The latter metabolite was not detected in its isogenic parent strain or a deletion mutant of the entire mtlABFD operon. In addition, the mtlD mutant strain exhibited a decreased MIC for H2O2, however virulence was unaffected in a model of septic arthritis.
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Affiliation(s)
- John G. Kenny
- Institute of Integrative Biology, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Josephine Moran
- Institute of Integrative Biology, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Stacey L. Kolar
- Department of Cell Biology, Microbiology & Molecular Biology, University of South Florida, Tampa, Florida, United States of America
| | - Alexander Ulanov
- Roy J. Carver Biotechnology Center, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Zhong Li
- Roy J. Carver Biotechnology Center, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Lindsey N. Shaw
- Department of Cell Biology, Microbiology & Molecular Biology, University of South Florida, Tampa, Florida, United States of America
| | - Elisabet Josefsson
- Department of Rheumatology and Inflammation Research, University of Gothenburg, Göteborg, Sweden
| | - Malcolm J. Horsburgh
- Institute of Integrative Biology, University of Liverpool, Liverpool, Merseyside, United Kingdom
- * E-mail:
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Lin YC, Anderson MJ, Kohler PL, Strandberg KL, Olson ME, Horswill AR, Schlievert PM, Peterson ML. Proinflammatory exoprotein characterization of toxic shock syndrome Staphylococcus aureus. Biochemistry 2011; 50:7157-67. [PMID: 21749039 DOI: 10.1021/bi200435n] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pulsed-field gel electrophoresis (PFGE) clonal type USA200 is the most widely disseminated Staphylococcus aureus colonizer of the nose and is a major cause of toxic shock syndrome (TSS). Exoproteins derived from these organisms have been suggested to contribute to their colonization and causation of human diseases but have not been well-characterized. Two representative S. aureus USA200 isolates, MNPE (α-toxin positive) and CDC587 (α-toxin mutant), isolated from pulmonary post-influenza TSS and menstrual vaginal TSS, respectively, were evaluated. Biochemical, immunobiological, and cell-based assays, including mass spectrometry, were used to identify key exoproteins derived from the strains that are responsible for proinflammatory and cytotoxic activity on human vaginal epithelial cells. Exoproteins associated with virulence were produced by both strains, and cytolysins (α-toxin and γ-toxin), superantigens, and proteases were identified as the major exoproteins, which caused epithelial cell inflammation and cytotoxicity. Exoprotein fractions from MNPE were more proinflammatory and cytotoxic than those from CDC587 due to high concentrations of α-toxin. CDC587 produced a small amount of α-toxin, despite the presence of a stop codon (TAG) at codon 113. Additional exotoxin identification studies of USA200 strain [S. aureus MN8 (α-toxin mutant)] confirmed that MN8 also produced low levels of α-toxin despite the same stop codon. The differences observed in virulence factor profiles of two USA200 strains provide insight into environmental factors that select for specific virulence factors. Cytolysins, superantigens, and proteases were identified as potential targets, where toxin neutralization may prevent or diminish epithelial damage associated with S. aureus.
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Affiliation(s)
- Ying-Chi Lin
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, Medical School University of Minnesota, Minneapolis, Minnesota 55455, USA
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Said KB, Zhu G, Zhao X. Organ- and Host-Specific Clonal Groups ofStaphylococcus aureusfrom Human Infections and Bovine Mastitis Revealed by the Clumping Factor A Gene. Foodborne Pathog Dis 2010; 7:111-9. [DOI: 10.1089/fpd.2009.0334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Guoqiang Zhu
- Department of Microbiology, College of Veterinary Science, Yanzhou University, Yanzhou, China
| | - Xin Zhao
- Department of Animal Science, McGill University, Quebec, Canada
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Relationship between virulence factor genes in bovineStaphylococcus aureussubclinical mastitis isolates and binding to anti-adhesin antibodies. J DAIRY RES 2009; 77:159-67. [DOI: 10.1017/s0022029909990598] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Staphylococcus aureusis the most common aetiologic agent of contagious bovine mastitis. It is characterized by a wide array of virulence factors. The differences among strains jeopardize the development of effective vaccines againstStaph. aureusmastitis. We tested the immunogenicity of a peptide subunit vaccine coding for three different adhesion factors, fibrinogen-binding protein (Efb), fibronectin-binding protein A (FnbpA) and clumping factor A (ClfA). Then we evaluated the influence of some virulence factors on the ability of specific anti-adhesin antibodies to react with sixteenStaph. aureusstrains isolated from bovine subclinical mastitis. Immunization with the recombinant adhesins stimulated a strong humoural (IgG and IgA) and mucosal IgA immune response in all animals tested. Hyperimmune serum recognized with diverse efficiency the sixteenStaph. aureusstrains and this circumstance correlated well with the level of expression of adhesins. Among the different virulence factors considered to classify strains,spagene polymorphisms showed the strongest influence on isolate reactions to hyperimmune serum. Our results indicate the importance of a disease- and environment-specific analysis of isolates. Thus, as opposed to other pathogens to obtain an effective vaccine we should characterize multiple strains and identify the prevalent virulence factors expressed.
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Regional profiling for determination of genotype diversity of mastitis-specific Staphylococcus aureus lineage in Canada by use of clumping factor A, pulsed-field gel electrophoresis, and spa typing. J Clin Microbiol 2009; 48:375-86. [PMID: 19955267 DOI: 10.1128/jcm.01768-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
One of the major concerns in global public health and the dairy industry is the emergence of host-specific virulent Staphylococcus aureus strains. The high degree of stability of the species genome renders detection of genetic microvariations difficult. Thus, approaches for the rapid tracking of specialized lineages are urgently needed. We used clumping factor A (clfA) to profile 87 bovine mastitis isolates from four regions in Canada and compared the results to those obtained by pulsed-field gel electrophoresis (PFGE) and spa typing. Twenty-five pulsotypes were obtained by PFGE with an index of discrimination of 0.91. These were assigned to six PFGE lineage groups A to F and seven spa types, including two novel ones. Group A had 48.3% of the isolates and group D had 43.7% of the isolates, while only 8% of the isolates were variable. The results of antimicrobial susceptibility testing indicated that all isolates were sensitive to methicillin and the non-beta-lactam antibiotics, while three isolates were resistant to penicillin and one isolate was resistant to tetracycline. All isolates had the clfA gene and belonged to 20 clfA repeat types with an index of discrimination of 0.90. The dominant clfA types, types X, Q, C, and Z, formed 82% and 43% of PFGE groups A and D, respectively, and had copy numbers that varied only within a narrow range of between 46 and 52 copies, implying clonal selection. The rest were variable and region specific. Furthermore, the dominant groups contained subpopulations in different regions across Canada. Sequence information confirmed the relatedness obtained by the use of clfA repeat copy numbers and other methods and further revealed the occurrence of full-repeat deletions and conserved host-specific codon-triplet position biases at 18-bp units. Thus, concordant with the results of PFGE and spa typing, clfA typing proved useful for revealing the clonal nature of the mastitis isolate lineage and for the rapid profiling of subpopulations with comparable discriminatory powers.
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Kenny JG, Ward D, Josefsson E, Jonsson IM, Hinds J, Rees HH, Lindsay JA, Tarkowski A, Horsburgh MJ. The Staphylococcus aureus response to unsaturated long chain free fatty acids: survival mechanisms and virulence implications. PLoS One 2009; 4:e4344. [PMID: 19183815 PMCID: PMC2629846 DOI: 10.1371/journal.pone.0004344] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 12/18/2008] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus is an important human commensal and opportunistic pathogen responsible for a wide range of infections. Long chain unsaturated free fatty acids represent a barrier to colonisation and infection by S. aureus and act as an antimicrobial component of the innate immune system where they are found on epithelial surfaces and in abscesses. Despite many contradictory reports, the precise anti-staphylococcal mode of action of free fatty acids remains undetermined. In this study, transcriptional (microarrays and qRT-PCR) and translational (proteomics) analyses were applied to ascertain the response of S. aureus to a range of free fatty acids. An increase in expression of the σB and CtsR stress response regulons was observed. This included increased expression of genes associated with staphyloxanthin synthesis, which has been linked to membrane stabilisation. Similarly, up-regulation of genes involved in capsule formation was recorded as were significant changes in the expression of genes associated with peptidoglycan synthesis and regulation. Overall, alterations were recorded predominantly in pathways involved in cellular energetics. In addition, sensitivity to linoleic acid of a range of defined (sigB, arcA, sasF, sarA, agr, crtM) and transposon-derived mutants (vraE, SAR2632) was determined. Taken together, these data indicate a common mode of action for long chain unsaturated fatty acids that involves disruption of the cell membrane, leading to interference with energy production within the bacterial cell. Contrary to data reported for other strains, the clinically important EMRSA-16 strain MRSA252 used in this study showed an increase in expression of the important virulence regulator RNAIII following all of the treatment conditions tested. An adaptive response by S. aureus of reducing cell surface hydrophobicity was also observed. Two fatty acid sensitive mutants created during this study were also shown to diplay altered pathogenesis as assessed by a murine arthritis model. Differences in the prevalence and clinical importance of S. aureus strains might partly be explained by their responses to antimicrobial fatty acids.
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Affiliation(s)
- John G. Kenny
- School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Deborah Ward
- School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Elisabet Josefsson
- Department of Rheumatology and Inflammation Research, University of Gothenburg, Göteborg, Sweden
| | - Ing-Marie Jonsson
- Department of Rheumatology and Inflammation Research, University of Gothenburg, Göteborg, Sweden
| | - Jason Hinds
- Division of Cellular & Molecular Medicine, St George's, University of London, London, United Kingdom
| | - Huw H. Rees
- School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Jodi A. Lindsay
- Division of Cellular & Molecular Medicine, St George's, University of London, London, United Kingdom
| | - Andrej Tarkowski
- Department of Rheumatology and Inflammation Research, University of Gothenburg, Göteborg, Sweden
| | - Malcolm J. Horsburgh
- School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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12
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Said KB, Ramotar K, Zhu G, Zhao X. Repeat-based subtyping and grouping of Staphylococcus aureus from human infections and bovine mastitis using the R-domain of the clumping factor A gene. Diagn Microbiol Infect Dis 2008; 63:24-37. [PMID: 18990534 DOI: 10.1016/j.diagmicrobio.2008.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Revised: 09/04/2008] [Accepted: 09/11/2008] [Indexed: 10/21/2022]
Abstract
Staphylococcus aureus has become an emerging public health concern. Markers capable of differentiating separate host-specific lineages are needed for tracing strain sources. Thus, a coding variable number tandem repeat-based typing was explored in this study, based on R-domain of clumping factor A (clfA) gene. DNA from isolates and strains of human infections and bovine mastitis were amplified and sequenced. Sequences of clfA from published strains were also analyzed. Results indicate that except one with 36 copies, 44 of the 55 R-domains had repeat copies between 44 and 57, whereas the remaining 10 had 59.5 to 73 copies. Furthermore, human isolates were polymorphic, while mastitis isolates were clonal. Phylogenetic grouping assigned host-specific strains into respective clusters. The repeats were stable during passages in milk, nutrient broth, and invasion of mammary cells showing suitability for typing. Our data show that the R-domain can be useful for typing and grouping host-specific lineages. Moreover, existence of variant repeats in human strains and the dominance of a clonal motif in mastitis may imply that a specific selection has occurred in the mammary gland.
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Affiliation(s)
- Kamaleldin B Said
- Department of Animal Science, McGill University, Ste Anne de Bellevue, Quebec H9X 3V9, Canada
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