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Jiang JH, Cameron DR, Nethercott C, Aires-de-Sousa M, Peleg AY. Virulence attributes of successful methicillin-resistant Staphylococcus aureus lineages. Clin Microbiol Rev 2023; 36:e0014822. [PMID: 37982596 PMCID: PMC10732075 DOI: 10.1128/cmr.00148-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe and often fatal infections. MRSA epidemics have occurred in waves, whereby a previously successful lineage has been replaced by a more fit and better adapted lineage. Selection pressures in both hospital and community settings are not uniform across the globe, which has resulted in geographically distinct epidemiology. This review focuses on the mechanisms that trigger the establishment and maintenance of current, dominant MRSA lineages across the globe. While the important role of antibiotic resistance will be mentioned throughout, factors which influence the capacity of S. aureus to colonize and cause disease within a host will be the primary focus of this review. We show that while MRSA possesses a diverse arsenal of toxins including alpha-toxin, the success of a lineage involves more than just producing toxins that damage the host. Success is often attributed to the acquisition or loss of genetic elements involved in colonization and niche adaptation such as the arginine catabolic mobile element, as well as the activity of regulatory systems, and shift metabolism accordingly (e.g., the accessory genome regulator, agr). Understanding exactly how specific MRSA clones cause prolonged epidemics may reveal targets for therapies, whereby both core (e.g., the alpha toxin) and acquired virulence factors (e.g., the Panton-Valentine leukocidin) may be nullified using anti-virulence strategies.
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Affiliation(s)
- Jhih-Hang Jiang
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - David R. Cameron
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Cara Nethercott
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Marta Aires-de-Sousa
- Laboratory of Molecular Genetics, Institutode Tecnologia Químicae Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Oeiras, Portugal
- Escola Superior de Saúde da Cruz Vermelha Portuguesa-Lisboa (ESSCVP-Lisboa), Lisbon, Portugal
| | - Anton Y. Peleg
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Centre to Impact Antimicrobial Resistance, Monash University, Clayton, Melbourne, Victoria, Australia
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da Luz BSR, de Rezende Rodovalho V, Nicolas A, Chabelskaya S, Jardin J, Briard-Bion V, Le Loir Y, de Carvalho Azevedo VA, Guédon É. Impact of Environmental Conditions on the Protein Content of Staphylococcus aureus and Its Derived Extracellular Vesicles. Microorganisms 2022; 10:microorganisms10091808. [PMID: 36144410 PMCID: PMC9506334 DOI: 10.3390/microorganisms10091808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/01/2022] [Accepted: 09/04/2022] [Indexed: 12/03/2022] Open
Abstract
Staphylococcus aureus, a major opportunistic pathogen in humans, produces extracellular vesicles (EVs) that are involved in cellular communication, the delivery of virulence factors, and modulation of the host immune system response. However, to date, the impact of culture conditions on the physicochemical and functional properties of S. aureus EVs is still largely unexplored. Here, we use a proteomic approach to provide a complete protein characterization of S. aureus HG003, a NCTC8325 derivative strain and its derived EVs under four growth conditions: early- and late-stationary growth phases, and in the absence and presence of a sub-inhibitory concentration of vancomycin. The HG003 EV protein composition in terms of subcellular localization, COG and KEGG categories, as well as their relative abundance are modulated by the environment and differs from that of whole-cell (WC). Moreover, the environmental conditions that were tested had a more pronounced impact on the EV protein composition when compared to the WC, supporting the existence of mechanisms for the selective packing of EV cargo. This study provides the first general picture of the impact of different growth conditions in the proteome of S. aureus EVs and its producing-cells and paves the way for future studies to understand better S. aureus EV production, composition, and roles.
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Affiliation(s)
- Brenda Silva Rosa da Luz
- INRAE, Institut Agro, STLO, F-35000 Rennes, France
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Vinícius de Rezende Rodovalho
- INRAE, Institut Agro, STLO, F-35000 Rennes, France
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil
| | | | - Svetlana Chabelskaya
- BRM (Bacterial Regulatory RNAs and Medicine) UMR_S 1230, Inserm 1230, University of Rennes 1, 35000 Rennes, France
| | | | | | - Yves Le Loir
- INRAE, Institut Agro, STLO, F-35000 Rennes, France
| | - Vasco Ariston de Carvalho Azevedo
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Éric Guédon
- INRAE, Institut Agro, STLO, F-35000 Rennes, France
- Correspondence:
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3
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K1 Antigen Is Associated with Different AST Profile in Escherichia coli: A One-Month-Long Pilot Study. Microorganisms 2021; 9:microorganisms9091884. [PMID: 34576781 PMCID: PMC8469396 DOI: 10.3390/microorganisms9091884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 11/25/2022] Open
Abstract
Escherichia coli is responsible for diseases of varying severity. The “K” antigen designates the capsular polysaccharides on the bacterial surface, which are mostly similar to those of highly pathogenic bacteria. The K1 antigen is often found in pathogenic E. coli. Aim: While the published studies on the AST profile of K1-positive E. coli have focused on pregnant women or newborns, this study aimed to characterize the AST profile of K1-positive E. coli independently of the clinical sample of isolation. Over a 4-week-long period, all patients hospitalized/consulting at the Poitiers University Hospital presenting a determined AST on E. coli were prospectively included to define their K1-status (Pastorex Meningitis) and to collect the clinical (age/sex) or biological metadata (AST/MIC). Among the 296 included samples, no differential representation was observed between K1 results regarding sample nature. K1-negative results were associated with multiple antibiotic-resistance (12.3% vs. 33.0%; p < 0.01). AST phenotypes differed between these groups, with a higher proportion of K1-negativity among resistant strains, especially on β-lactams (ureidopenicillin, 25.8% vs. 14.9%; and ampicillin/inhibitor, 50.0% vs. 26.8%; p < 0.05) or quinolone (19.8% vs. 7.0%) and sulfamethoxazole-trimethoprim (30.2% vs. 12.3%) (p < 0.01). This study analyzed E. coli ASTs in clinical samples of all types, regarding their K1-antigen status.
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Zeouk I, Ouedrhiri W, Sifaoui I, Bazzocchi IL, Piñero JE, Jiménez IA, Lorenzo-Morales J, Bekhti K. Bioguided Isolation of Active Compounds from Rhamnus alaternus against Methicillin-Resistant Staphylococcus aureus (MRSA) and Panton-Valentine Leucocidin Positive Strains (MSSA-PVL). Molecules 2021; 26:molecules26144352. [PMID: 34299627 PMCID: PMC8306708 DOI: 10.3390/molecules26144352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 01/24/2023] Open
Abstract
Despite intensified efforts to develop an effective antibiotic, S. aureus is still a major cause of mortality and morbidity worldwide. The multidrug resistance of bacteria has considerably increased the difficulties of scientific research and the concomitant emergence of resistance is to be expected. In this study we have investigated the in vitro activity of 15 ethanol extracts prepared from Moroccan medicinal plants traditionally used for treatment of skin infections. Among the tested species I. viscosa, C. oxyacantha, R. tinctorum, A. herba alba, and B. hispanica showed moderate anti-staphylococcal activity. However, R. alaternus showed promising growth-inhibitory effects against specific pathogenic bacteria especially methicillin-susceptible Staphylococcus aureus Panton-Valentine leucocidin positive (MSSA-PVL) and methicillin-resistant S. aureus (MRSA). The bioguided fractionation of this plant using successive chromatographic separations followed by nuclear magnetic resonance (NMR) and mass spectrometry (MS) including EIMS and HREIMS analysis yielded the emodin (1) and kaempferol (2). Emodin being the most active with MICs ranging between 15.62 and 1.95 µg/mL and showing higher activity against the tested strains in comparison with the crude extract, its mechanism of action and the structure-activity relationship were interestingly discussed. The active compound has not displayed toxicity toward murine macrophage cells. The results obtained in the current study support the traditional uses of R. alaternus and suggest that this species could be a good source for the development of new anti-staphylococcal agents.
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Affiliation(s)
- Ikrame Zeouk
- Instituto Universitario De Enfermedades Tropicales y Salud Pública de Canarias, Universidad de la Laguna, Avda. Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Spain;
- Laboratory of Microbial Biotechnology and Bioactive Molecules, Department of Biology, Faculty of Sciences and Techniques, Sidi Mohamed Ben Abdellah University, Fez 2202, Morocco;
- Correspondence: (I.Z.); (J.E.P.); (J.L.-M.); Tel.: +212-621-290-377 (I.Z.); +349-22-316-502 (J.E.P.); +349-22-318-402 (J.L.-M.)
| | - Wessal Ouedrhiri
- Laboratory of Engineering, Electrochemistry, Modeling and Environment, Department of Chemistry, Faculty of Science, Sidi Mohamed Ben Abdellah University, Fez 2202, Morocco;
| | - Ines Sifaoui
- Instituto Universitario De Enfermedades Tropicales y Salud Pública de Canarias, Universidad de la Laguna, Avda. Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Spain;
- Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de la Laguna, 38203 La Laguna, Spain
- Red de Investigación Colaborativa en Enfermedades Tropicales (RICET), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Isabel L. Bazzocchi
- Departamento de Química Orgánica, Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, Avenida Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain; (I.L.B.); (I.A.J.)
| | - José E. Piñero
- Instituto Universitario De Enfermedades Tropicales y Salud Pública de Canarias, Universidad de la Laguna, Avda. Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Spain;
- Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de la Laguna, 38203 La Laguna, Spain
- Red de Investigación Colaborativa en Enfermedades Tropicales (RICET), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (I.Z.); (J.E.P.); (J.L.-M.); Tel.: +212-621-290-377 (I.Z.); +349-22-316-502 (J.E.P.); +349-22-318-402 (J.L.-M.)
| | - Ignacio A. Jiménez
- Departamento de Química Orgánica, Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, Avenida Astrofísico Francisco Sánchez 2, 38206 La Laguna, Spain; (I.L.B.); (I.A.J.)
| | - Jacob Lorenzo-Morales
- Instituto Universitario De Enfermedades Tropicales y Salud Pública de Canarias, Universidad de la Laguna, Avda. Astrofísico Fco. Sánchez, S/N, 38203 La Laguna, Spain;
- Departamento de Obstetricia, Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Universidad de la Laguna, 38203 La Laguna, Spain
- Red de Investigación Colaborativa en Enfermedades Tropicales (RICET), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (I.Z.); (J.E.P.); (J.L.-M.); Tel.: +212-621-290-377 (I.Z.); +349-22-316-502 (J.E.P.); +349-22-318-402 (J.L.-M.)
| | - Khadija Bekhti
- Laboratory of Microbial Biotechnology and Bioactive Molecules, Department of Biology, Faculty of Sciences and Techniques, Sidi Mohamed Ben Abdellah University, Fez 2202, Morocco;
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5
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Rossato AM, Primon-Barros M, Dias CAG, d'Azevedo PA. Vancomycin MIC and agr dysfunction in invasive MRSA infections in southern Brazil. Braz J Microbiol 2020; 51:1819-1823. [PMID: 33074551 DOI: 10.1007/s42770-020-00384-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022] Open
Abstract
In methicillin-resistant Staphylococcus aureus (MRSA) treatment, the vancomycin minimum inhibitory concentration (MIC) increase, vancomycin heteroresistance (hVISA) presence, and accessory gene regulator (agr) dysfunction are predictors of vancomycin therapy failure. This study evaluated the association between vancomycin MIC (≥ 1.0 μg/mL) and agr dysfunction in invasive MRSA isolates. Vancomycin MIC, hVISA phenotype, agr group, and function were determined in 171 MRSA isolates obtained between 2014 and 2019 from hospitals in Porto Alegre, Brazil. All MRSA were susceptible to vancomycin; 16.4% of these had MIC ≥ 1.0 μg/mL. Seventeen MRSA isolates expressed the hVISA phenotype; 35.3% of them had MIC of 1.5 μg/mL. agr groups I (40.9%) and II (47.1%) were the most found groups for MRSA and hVISA isolates, respectively. The proportion of MRSA with vancomycin MIC ≥ 1.0 μg/mL in agr group II was significantly higher than in agr groups I and III (p = 0.002). agr dysfunction was observed in 4.7% (8/171) of MRSA, especially those with vancomycin MIC ≥ 1.0 μg/mL (p < 0.001). In addition, six isolates (35.3%; 6/17) with hVISA phenotype presented agr dysfunction, which was significantly higher than that in non-hVISA phenotype (p < 0.001). In conclusion, agr dysfunction in MRSA is associated with vancomycin MIC ≥ 1.0 μg/mL and hVISA phenotype, which suggests that agr dysfunction might confer potential advantages on MRSA to survive in invasive infections.
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Affiliation(s)
- Adriana Medianeira Rossato
- Basic Health Department, Postgraduate Program in Health Sciences of Porto Alegre (PPGCS), Federal University of Health Science of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.
| | - Muriel Primon-Barros
- Basic Health Department, Postgraduate Program in Health Sciences of Porto Alegre (PPGCS), Federal University of Health Science of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Cícero Armídio Gomes Dias
- Basic Health Department, Postgraduate Program in Health Sciences of Porto Alegre (PPGCS), Federal University of Health Science of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
| | - Pedro Alves d'Azevedo
- Basic Health Department, Postgraduate Program in Health Sciences of Porto Alegre (PPGCS), Federal University of Health Science of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
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6
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Kochan K, Nethercott C, Taghavimoghaddam J, Richardson Z, Lai E, Crawford SA, Peleg AY, Wood BR, Heraud P. Rapid Approach for Detection of Antibiotic Resistance in Bacteria Using Vibrational Spectroscopy. Anal Chem 2020; 92:8235-8243. [PMID: 32407103 DOI: 10.1021/acs.analchem.0c00474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here, we applied vibrational spectroscopy to investigate the drug response following incubation of S. aureus with oxacillin. The main focus of this work was to identify the chemical changes caused by oxacillin over time and to determine the feasibility of the spectroscopic approach to detect antimicrobial resistance. The oxacillin-induced changes in the chemical composition of susceptible bacteria, preceding (and leading to) the inhibition of growth, included an increase in the relative content of nucleic acids, alteration in the α-helical/β-sheet protein ratio, structural changes in carbohydrates (observed via changes in the band at 1035 cm-1), and significant thickening of the cell wall. These observations enabled a dose-dependent discrimination between susceptible bacteria incubated with and without oxacillin after 120 min. In methicillin resistant strains, no spectral differences were observed between cells, regardless of drug exposure. These results pave the way for a new, rapid spectroscopic approach to detect drug resistance in pathogens, based on their early positive/negative drug response.
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Affiliation(s)
- Kamila Kochan
- Centre for Biospectroscopy and School of Chemistry, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
| | - Cara Nethercott
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
| | | | - Zack Richardson
- Centre for Biospectroscopy and School of Chemistry, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
| | - Elizabeth Lai
- Centre for Biospectroscopy and School of Chemistry, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
| | - Simon A Crawford
- The Ramaciotti Centre for Cryo Electron Microscopy, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
| | - Anton Y Peleg
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne 3004, Victoria, Australia
| | - Bayden R Wood
- Centre for Biospectroscopy and School of Chemistry, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia.,School of Chemistry, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
| | - Philip Heraud
- Centre for Biospectroscopy and School of Chemistry, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia.,Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton Campus, Clayton 3800, Victoria, Australia
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Sanson MA, Macias OR, Shah BJ, Hanson B, Vega LA, Alamarat Z, Flores AR. Unexpected relationships between frequency of antimicrobial resistance, disease phenotype and emm type in group A Streptococcus. Microb Genom 2019; 5:e000316. [PMID: 31755853 PMCID: PMC6927302 DOI: 10.1099/mgen.0.000316] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Despite universal susceptibility to β-lactams, resistance to second-line antimicrobials (e.g. erythromycin) is increasingly common among group A Streptococcus (GAS). To better understand the frequency of regional GAS antimicrobial resistance, we screened a previously described GAS strain collection from Houston, TX, USA, for resistance to commonly used antimicrobials. A total of 100/929 (10.8 %) showed resistance to at least one antimicrobial. Tetracycline resistance was identified in 52 (5.6 %) GAS strains. The cumulative frequency of erythromycin and clindamycin resistance [macrolide (M) and macrolide-lincosamide-streptogramin (MLS) phenotypes] was greatest among invasive GAS strains (9.9 %) compared to that of strains derived from any other infection type (5.9 %, P=0.045). We identified emm types 11, 75, 77 and 92 as the only emm types with high (e.g. >50 %) within-emm type resistance and contributing to the majority (24/26; 92 %) of erythromycin/clindamycin resistance in invasive GAS. High-frequency resistance emm types were also significantly overrepresented in invasive GAS strains as indicated by invasive index. We performed whole-genome sequencing to define genetic elements associated with resistance among emm types 11, 75, 77 and 92. Diverse mobile elements contributed to GAS resistance including transposons, integrative conjugative elements, prophage and a plasmid. Phylogenetic analysis suggests recent clonal emergence of emm92 GAS strains. Our findings indicate that less frequently encountered GAS emm types disproportionately contribute to resistance phenotypes, are defined by diverse mobile genetic elements and may favour invasive disease.
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Affiliation(s)
- Misu A. Sanson
- Division of Infectious Diseases, Department of Pediatrics, McGovern Medical School, Houston, TX, USA
| | - Olga R. Macias
- Division of Infectious Diseases, Department of Pediatrics, McGovern Medical School, Houston, TX, USA
| | - Brittany J. Shah
- Division of Infectious Diseases, Department of Pediatrics, McGovern Medical School, Houston, TX, USA
| | - Blake Hanson
- Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Sciences Center at Houston, Houston, TX, USA
| | - Luis Alberto Vega
- Division of Infectious Diseases, Department of Pediatrics, McGovern Medical School, Houston, TX, USA
| | - Zain Alamarat
- Division of Infectious Diseases, Department of Pediatrics, McGovern Medical School, Houston, TX, USA
| | - Anthony R. Flores
- Division of Infectious Diseases, Department of Pediatrics, McGovern Medical School, Houston, TX, USA,Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Sciences Center at Houston, Houston, TX, USA,*Correspondence: Anthony R. Flores,
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8
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Welte T, Kantecki M, Stone GG, Hammond J. Ceftaroline fosamil as a potential treatment option for Staphylococcus aureus community-acquired pneumonia in adults. Int J Antimicrob Agents 2019; 54:410-422. [PMID: 31404620 DOI: 10.1016/j.ijantimicag.2019.08.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/25/2019] [Accepted: 08/05/2019] [Indexed: 02/07/2023]
Abstract
Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA), is an important aetiological cause of community-acquired pneumonia (CAP) and associated with significant morbidity and mortality. Empiric therapy for CAP frequently consists of β-lactam monotherapy or β-lactam/macrolide combination therapy. However, such agents are often ineffective against S. aureus and do not reflect the emergence and increasing prevalence of MRSA in the community setting. Ceftaroline fosamil is a fifth-generation parenteral cephalosporin with broad-spectrum activity against Gram-positive pathogens - such as S. aureus (including MRSA), Streptococcus pneumoniae and Streptococcus pyogenes - and typical Gram-negative pathogens, including Haemophilus influenzae and Moraxella catarrhalis. The approval of ceftaroline fosamil in the United States and Europe for the treatment of adults with moderate-to-severe CAP was based on two phase 3 trials (FOCUS 1 and 2), which demonstrated that ceftaroline fosamil was non-inferior to ceftriaxone, a standard empiric treatment for CAP, while exhibiting a comparable safety profile. Although head-to-head trials of ceftaroline fosamil versus comparators against MRSA CAP are lacking, the effectiveness of ceftaroline fosamil in subpopulations of patients not covered by phase 3 trials (e.g. those with MRSA CAP or severe renal impairment) has been demonstrated in the Clinical Assessment Program and Teflaro Utilization Registry (CAPTURE) study. As ineffective empiric therapy is associated with adverse outcomes, including mortality and increased costs, ceftaroline fosamil, with its extended spectrum of activity, is an attractive alternative to standard antibiotic CAP regimens.
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Affiliation(s)
- Tobias Welte
- University of Hannover, School of Medicine, Carl-Neuberg-Straße, 30625 Hannover, Germany.
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9
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Accessory gene regulator (agr) dysfunction was unusual in Staphylococcus aureus isolated from Chinese children. BMC Microbiol 2019; 19:95. [PMID: 31088356 PMCID: PMC6518674 DOI: 10.1186/s12866-019-1465-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 04/26/2019] [Indexed: 12/18/2022] Open
Abstract
Background Staphylococcus aureus (S. aureus) with accessory gene regulator (agr) dysfunction occurs in health care settings. This study evaluated the prevalence and the molecular and drug resistance characteristics of S. aureus with dysfunctional agr in a pediatric population in Beijing, China. Results A total of 269 nonduplicate S. aureus clinical isolates were isolated from Beijing Children’s Hospital, including 211 methicillin-resistant S. aureus (MRSA) from September 2010–2017 and 58 methicillin-sensitive S. aureus (MSSA) from February 2016–2017. Only 8 MRSA and 2 MSSA isolates were identified as agr dysfunction, and the overall prevalence rate was 3.7%. For MRSA isolates, ST59-SCCmec IV and ST239-SCCmec III were the most common clones, and the prevalence rate of agr dysfunction in ST239-SCCmec III isolates (17.39%) was significantly higher than in ST59-SCCmec IV (1.69%) and other genotype strains (P = 0.006). Among the agr dysfunctional isolates, only one MRSA ST59 isolate and one MSSA ST22 isolate harbored pvl. No significant difference was detected between agr dysfunction and agr functional isolates regarding the biofilm formation ability (P = 0.4972); however, 9/10 agr dysfunctional isolates could effectuate strong biofilm formation and multidrug resistance. Among MRSA, the non-susceptibility rates to ciprofloxacin, gentamicin, and trimethoprim-sulfamethoxazole were significantly higher in agr dysfunctional isolates than in isolates with functional agr (P < 0.05). Two isolates belonging to ST239 had no mutations in agr locus, but a synonymous mutation was found in agrA in another ST239 isolate. The inactivating mutations were detected in other seven agr dysfunctional isolates. The variants were characterized by non-synonymous changes (n = 5) and frameshift mutations (insertions, n = 2), which mainly occurred in agrC and agrA. Conclusions The results showed that agr dysfunctional S. aureus was not common in Chinese children, and ST59-SCCmec IV was associated with lower prevalence of agr dysfunction as compared to ST239-SCCmec III isolates. The agr dysfunctional isolates were healthcare-associated, multidrug resistant and form strong biofilm, which suggested that agr dysfunction might offer potential advantages for S. aureus to survive in a medical environment.
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Brignoli T, Manetti AGO, Rosini R, Haag AF, Scarlato V, Bagnoli F, Delany I. Absence of Protein A Expression Is Associated With Higher Capsule Production in Staphylococcal Isolates. Front Microbiol 2019; 10:863. [PMID: 31133995 PMCID: PMC6523524 DOI: 10.3389/fmicb.2019.00863] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/04/2019] [Indexed: 12/19/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen, and a leading cause of soft tissue and blood stream infections. One of the causes of its success as a pathogen is the peculiar array of immune evasion factors through which the bacterium avoids host defenses, where the staphylococcal protein A (SpA) plays a major role thanks to its IgG binding activities. Moreover, SpA has recently been proposed as a promising vaccine antigen. In this study, we evaluated the expression of SpA in a collection of staphylococcal strains, about 7% of which did not express SpA (SpA- strains), despite the presence of the gene. By a comparative genomic analysis, we identified that a mutation in the spa 5′ UTR sequence affecting the RBS is responsible for the loss of SpA in a subset of SpA- strains. Using a high-throughput qRT-PCR approach on a selected panel of virulence-related genes, we identified that the SpA- phenotype is associated with lower spa transcript levels and increased expression and production of capsule as well as other changes in the transcription of several key virulence factors. Our data suggest that the SpA- phenotype has occurred in geographically distinct strains through different molecular mechanisms including both mutation, leading likely to translation alterations, and transcriptional deregulation. Furthermore, we provide evidence that SpA- strains are highly susceptible to phagocytic uptake mediated by anti-capsule antibodies. These data suggest that S. aureus may alter its virulence factor expression pattern as an adaptation to the host or environment. Vaccination strategies targeting both SpA and capsule could therefore result in broader coverage against staphylococcal isolates than SpA alone.
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Affiliation(s)
- Tarcisio Brignoli
- GSK Vaccines, Siena, Italy.,Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Bologna, Italy
| | | | | | - Andreas F Haag
- GSK Vaccines, Siena, Italy.,Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Vincenzo Scarlato
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, Bologna, Italy
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11
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Antimicrobial Stewardship Opportunities in Patients with Bacteremia Not Identified by BioFire FilmArray. J Clin Microbiol 2019; 57:JCM.01941-18. [PMID: 30814265 DOI: 10.1128/jcm.01941-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/17/2019] [Indexed: 01/02/2023] Open
Abstract
A subset of bacteremia cases are caused by organisms not detected by a rapid-diagnostics platform, BioFire blood culture identification (BCID), with unknown clinical characteristics and outcomes. Patients with ≥1 positive blood culture over a 15-month period were grouped by negative (NB-PC) versus positive (PB-PC) BioFire BCID results and compared with respect to demographics, infection characteristics, antibiotic therapy, and outcomes (length of hospital stay [LOS] and in-hospital mortality). Six percent of 1,044 positive blood cultures were NB-PC. The overall mean age was 65 ± 22 years, 54% of the patients were male, and most were admitted from home; fewer NB-PC had diabetes (19% versus 31%, P = 0.0469), although the intensive care unit admission data were similar. Anaerobes were identified in 57% of the bacteremia cases from the NB-PC group by conventional methods: Bacteroides spp. (30%), Clostridium (11%), and Fusobacterium spp. (8%). Final identification of the NB-PC pathogen was delayed by 2 days (P < 0.01) versus the PB-PC group. The sources of bacteremia were more frequently unknown for the NB-PC group (32% versus 11%, P < 0.01) and of pelvic origin (5% versus 0.1%, P < 0.01) compared to urine (31% versus 9%, P < 0.01) for the PB-PC patients. Fewer NB-PC patients received effective treatment before (68% versus 84%, P = 0.017) and after BCID results (82% versus 96%, P = 0.0048). The median LOS was similar (7 days), but more NB-PC patients died from infection (26% versus 8%, P < 0.01). Our findings affirm the need for the inclusion of anaerobes in BioFire BCID or other rapid diagnostic platforms to facilitate the prompt initiation of effective therapy for bacteremia.
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12
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Yang N, Teng D, Mao R, Hao Y, Wang X, Wang Z, Wang X, Wang J. A recombinant fungal defensin-like peptide-P2 combats multidrug-resistant Staphylococcus aureus and biofilms. Appl Microbiol Biotechnol 2019; 103:5193-5213. [PMID: 31025073 DOI: 10.1007/s00253-019-09785-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/04/2019] [Accepted: 03/19/2019] [Indexed: 01/10/2023]
Abstract
There is an urgent need to discover new active drugs to combat methicillin-resistant Staphylococcus aureus, which is a serious threat to humans and animals and incompletely eliminated by antibiotics due to its intracellular accumulation in host cells, production of biofilms, and persisters. Fungal defensin-like peptides (DLPs) are emerging as a potential source of new antibacterial drugs due to their potent antibacterial activity. In this study, nine novel fungal DLPs were firstly identified by querying against UniProt databases and expressed in Pichia pastoris, and their antibacterial and anti-biofilm ability were tested against multidrug-resistant (MDR) S. aureus. Results showed that among them, P2, the highest activity and expression level, showed low toxicity, no resistance, and high stability. Minimal inhibitory concentrations (MICs) of P2 against Gram-positive bacteria were < 2 μg/mL. P2 exhibited the potent activity against intracellular MDR S. aureus (bacterial reduction in 80-97%) in RAW264.7 macrophages. P2 bound to/disrupted bacterial DNA, wrinkled outer membranes and permeabilized cytoplasmic membranes, but maintained the integrity of bacterial cells. P2 inhibited/eradicated the biofilm and killed 99% persister bacteria, which were resistant to 100× MIC vancomycin. P2 upregulated the anti-inflammatory cytokine (IL-10) and downregulated pro-inflammatory cytokines (TNF-α/IL-1β) and chemokine (MCP-1) levels in RAW 264.7 macrophages and in mice, respectively. Five milligram per kilogram P2 enhanced the survival of S. aureus-infected mice (100%), superior to vancomycin (30 mg/kg), inhibited the bacterial translocation, and alleviated multiple-organ injuries (liver, spleen, kidney, and lung). These data suggest that P2 may be a candidate for novel antimicrobial agents against MDR staphylococcal infections.
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Affiliation(s)
- Na Yang
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Da Teng
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Ruoyu Mao
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Ya Hao
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Xiao Wang
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Zhenlong Wang
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China
| | - Xiumin Wang
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China.
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.
| | - Jianhua Wang
- Team of Alternatives to Antibiotics, Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China.
- Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.
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13
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Godoy-Santos F, Pinto MS, Barbosa AAT, Brito MAVP, Mantovani HC. Efficacy of a Ruminal Bacteriocin Against Pure and Mixed Cultures of Bovine Mastitis Pathogens. Indian J Microbiol 2019; 59:304-312. [PMID: 31388207 DOI: 10.1007/s12088-019-00799-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/20/2019] [Indexed: 12/11/2022] Open
Abstract
Bacteriocins have been suggested as an alternative to conventional antibiotics for the prevention and treatment of mastitis infections. Predominant bacteria associated with bovine mastitis (n = 276 isolates) were evaluated for their susceptibility to bovicin HC5, a ruminal bacteriocin produced by Streptococcus equinus HC5. Bovicin HC5 inhibited most (> 80%) of the streptococcal and staphylococcal strains tested, but showed no effect against Escherichia coli strains. Susceptibility and resistance testing indicated that approximately 95% of the S. aureus strains were inhibited by concentrations of bovicin HC5 varying from 40 to 2560 AU ml-1. Bovicin HC5 (62.50 AU ml-1) also inhibited the growth of aerobic and anaerobic mixed cultures of S. aureus and S. agalactiae, but the combination with 0.25 mmol l-1 of EDTA showed even greater bactericidal activity. These results demonstrate that bovicin HC5 is effective against the most prevalent pathogens found in contagious udder infections and could complement the use antibiotics in mastitis prophylaxis and therapy.
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Affiliation(s)
- Fernanda Godoy-Santos
- 1Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900 Brazil
| | - Marcelo S Pinto
- 1Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900 Brazil.,2Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Brasília, Brazil
| | - Ana A T Barbosa
- 1Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900 Brazil.,3Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe Brazil
| | | | - Hilário C Mantovani
- 1Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900 Brazil
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14
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Subramanian D, Natarajan J. RNA-seq analysis reveals resistome genes and signalling pathway associated with vancomycin-intermediate Staphylococcus aureus. Indian J Med Microbiol 2019; 37:173-185. [PMID: 31745016 DOI: 10.4103/ijmm.ijmm_18_311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Context Vancomycin-intermediate Staphylococcus aureus remains one of the most prevalent multidrug-resistant pathogens causing healthcare infections that are difficult to treat. Aims This study uses a comprehensive computational analysis to systematically investigate various gene expression profiles of resistant and sensitive S. aureus strains on exposure to antibiotics. Settings and Design The transcriptional changes leading to the development of multiple antibiotic resistance were examined by an integrative analysis of nine differential expression experiments under selected conditions of vancomycin-intermediate and -sensitive strains for four different antibiotics using publicly available RNA-Seq datasets. Materials and Methods For each antibiotic, three experimental conditions for expression analysis were selected to identify those genes that are particularly involved in the development of resistance. The results were further scrutinised to generate a resistome that can be analysed for their role in the development or adaptation to antibiotic resistance. Results The 99 genes in the resistome are then compiled to create a multiple drug resistome of 25 known and novel genes identified to play a part in antibiotic resistance. The inclusion of agr genes and associated virulence factors in the identified resistome supports the role of agr quorum sensing system in multiple drug resistance. In addition, enrichment analysis also identified the kyoto encyclopedia of genes and genomes (KEGG) pathways - quorum sensing and two-component system pathways - in the resistome gene set. Conclusion Further studies on understanding the role of the identified molecular targets such as SAA6008_00181, SAA6008_01127, agrA, agrC and coa in adapting to the pressure of antibiotics at sub-inhibitory concentrations can help in learning the molecular mechanisms causing resistance to the pathogens as well as finding other potential therapeutics.
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Affiliation(s)
- Devika Subramanian
- Department of Bioinformatics, Data Mining and Text Mining Laboratory, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - Jeyakumar Natarajan
- Department of Bioinformatics, Data Mining and Text Mining Laboratory, Bharathiar University, Coimbatore, Tamil Nadu, India
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15
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Islam MA, Parveen S, Rahman M, Huq M, Nabi A, Khan ZUM, Ahmed N, Wagenaar JA. Occurrence and Characterization of Methicillin Resistant Staphylococcus aureus in Processed Raw Foods and Ready-to-Eat Foods in an Urban Setting of a Developing Country. Front Microbiol 2019; 10:503. [PMID: 30923520 PMCID: PMC6426745 DOI: 10.3389/fmicb.2019.00503] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 02/27/2019] [Indexed: 01/09/2023] Open
Abstract
Infections by methicillin-resistant Staphylococcus aureus (MRSA) are gradually increasing in the community. In this study, we investigated a total of 162 food samples including 112 ready-to-eat (RTE) foods and 40 processed raw meat and fish samples collected from retail vendors in Dhaka, Bangladesh and determined the occurrence of toxigenic S. aureus and MRSA. Around 22% of samples were positive for S. aureus, RTE foods being more positive (23%) than the processed raw meat/fish samples (18%). Among 35 S. aureus isolates, 74% were resistant to erythromycin, 49% to ciprofloxacin and around 30% to oxacillin and cefoxitin. Around 37% of isolates were resistant to ≥3 classes of antibiotics and 26% of isolates (n = 9) were identified as MRSA. Majority of the isolates were positive for enterotoxin genes (74%), followed by pvl gene (71%), toxic shock syndrome toxin (tsst) gene (17%) and exfoliative toxin genes (11%). Multi locus sequence typing (MLST) of 9 MRSA isolates identified four different types such as ST80 (n = 3), ST6 (n = 2), ST239 (n = 2) and ST361 (n = 2). spa typing of MRSA isolates revealed seven different types including t1198 (n = 2), t315 (n = 2), t037 (n = 1), t275 (n = 1), t304 (n = 1), t8731 (n = 1) and t10546 (n = 1). To our knowledge, this is the first report entailing baseline data on the occurrence of MRSA in RTE foods in Dhaka highlighting a potential public health risk to street food consumers.
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Affiliation(s)
- Mohammad Aminul Islam
- Food Microbiology Laboratory, Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Sahana Parveen
- Institute of Food Science and Technology, Bangladesh Council of Scientific and Industrial Research, Dhaka, Bangladesh.,Department of Botany, Jahangirnagar University, Dhaka, Bangladesh
| | - Mahdia Rahman
- Food Microbiology Laboratory, Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Mohsina Huq
- Food Microbiology Laboratory, Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Ashikun Nabi
- Food Microbiology Laboratory, Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | | | - Niyaz Ahmed
- Laboratory Sciences and Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Jaap A Wagenaar
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, Netherlands.,Wageningen Bioveterinary Research, Lelystad, Netherlands
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16
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Tahmasebi H, Dehbashi S, Arabestani MR. Association between the accessory gene regulator (agr) locus and the presence of superantigen genes in clinical isolates of methicillin-resistant Staphylococcus aureus. BMC Res Notes 2019; 12:130. [PMID: 30871616 PMCID: PMC6419358 DOI: 10.1186/s13104-019-4166-7] [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: 12/17/2018] [Accepted: 03/06/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Methicillin-resistant Staphylococcus aureus cause to a variety of hard to cure infections. MRSA isolates also, produce an arsenal of virulence factors contribute to severe infections. The aim of this study was to find out the relationship between agr locus and presence of S. aureus superantigens (SAgs). RESULTS Clinical isolates in two groups from two different states of Iran were collected. Antibiotic resistance patterns, agr typing, and virulence factor genes prevalence were identified and relationship between them was analyzed using SPSS software version16. Most of the samples were collected from wound 39 isolates in Group 1 and 61 isolates in Group 2. Frequency of MRSA strains was 38.1% in Group 1 and 52.1% in Group 2. Also, the most common resistance among both groups was to penicillin. agr positive isolates were detected in 132 isolates of Group 1 and 104 isolates of Group 2. In Conclusion, a significant relationship between the SAgs frequency and agr locus in both groups has been indicated. The production of superantigens in S. aureus plays an important role in the classification of agr locus, and this locus can affect differently in methicillin-resistant strains.
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Affiliation(s)
- Hamed Tahmasebi
- Microbiology Department, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Sanaz Dehbashi
- Microbiology Department, Faculty of Medicine, Hamadan University of Medical Sciences, Pajoohesh Junction, Hamadan, Iran
| | - Mohammad Reza Arabestani
- Department of Microbiology, School of Medicine, University of Hamadan, Hamadan, Iran. .,Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
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17
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Guérillot R, Li L, Baines S, Howden B, Schultz MB, Seemann T, Monk I, Pidot SJ, Gao W, Giulieri S, Gonçalves da Silva A, D’Agata A, Tomita T, Peleg AY, Stinear TP, Howden BP. Comprehensive antibiotic-linked mutation assessment by resistance mutation sequencing (RM-seq). Genome Med 2018; 10:63. [PMID: 30165908 PMCID: PMC6117896 DOI: 10.1186/s13073-018-0572-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 07/24/2018] [Indexed: 12/15/2022] Open
Abstract
Mutation acquisition is a major mechanism of bacterial antibiotic resistance that remains insufficiently characterised. Here we present RM-seq, a new amplicon-based deep sequencing workflow based on a molecular barcoding technique adapted from Low Error Amplicon sequencing (LEA-seq). RM-seq allows detection and functional assessment of mutational resistance at high throughput from mixed bacterial populations. The sensitive detection of very low-frequency resistant sub-populations permits characterisation of antibiotic-linked mutational repertoires in vitro and detection of rare resistant populations during infections. Accurate quantification of resistance mutations enables phenotypic screening of mutations conferring pleiotropic phenotypes such as in vivo persistence, collateral sensitivity or cross-resistance. RM-seq will facilitate comprehensive detection, characterisation and surveillance of resistant bacterial populations ( https://github.com/rguerillot/RM-seq ).
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Affiliation(s)
- Romain Guérillot
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Lucy Li
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Sarah Baines
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Brian Howden
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Mark B. Schultz
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Torsten Seemann
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, Victoria Australia
| | - Ian Monk
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Sacha J. Pidot
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Wei Gao
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Stefano Giulieri
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Anders Gonçalves da Silva
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Anthony D’Agata
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Takehiro Tomita
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Anton Y. Peleg
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria Australia
- Infection and Immunity Theme, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Doherty Applied Microbial Genomics, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Microbiological Diagnostic Unit Public Health Laboratory, The University of Melbourne at the Peter Doherty Institute for Infection & Immunity, Melbourne, Victoria Australia
- Infectious Diseases Department, Austin Health, Heidelberg, Victoria Australia
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18
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Tadesse S, Alemayehu H, Tenna A, Tadesse G, Tessema TS, Shibeshi W, Eguale T. Antimicrobial resistance profile of Staphylococcus aureus isolated from patients with infection at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. BMC Pharmacol Toxicol 2018; 19:24. [PMID: 29784040 PMCID: PMC5963020 DOI: 10.1186/s40360-018-0210-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 04/26/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Staphylococcus aureus is one of the major pathogens of public health importance responsible for various forms of infection. Development of resistance to commonly used antimicrobials limited treatment options against infections due to this pathogen. Antimicrobial resistance profile of Staphylococcus aureus isolated from patients with surgical site infection and ear infection and corresponding nasal swab was investigated in Tikur Anbessa Specialized Hospital (TASH), Addis Ababa, Ethiopia. METHODS Wound and corresponding nasal swabs from patients with surgical site infection from general surgery ward (n = 14), orthopedic ward (n = 21) and those with otitis media (n = 59) from Ear Nose and Throat (ENT) ward were cultured for S. aureus isolation according to standard procedures from December 2013 to June 2014. Isolates were investigated for susceptibility to panel of 17 antimicrobials using Kirby Bauer disc diffusion assay. Susceptibility to methicillin was phenotypically determined based on sensitivity of isolates to cefoxitin and oxacillin. RESULTS A total of 79 S. aureus isolates were recovered from 54(57.4%) of patients. The isolates were resistant to ampicillin (100%), oxacillin and cefoxitin (68.4%, each), clindamycin (63.3%), cephalothin (59.5%), tetracycline (57%), sulfamethoxazole + trimethoprim and bacitracin (53.2%, each), and erythromycin (51.9%). Resistance to two or more antimicrobials was recorded in 74 (95%) of the isolates, while resistance to 3 or more antimicrobials was detected in 65(82.3%) of the isolates. Fifty-four (68.4%) of the isolates were methicillin resistant S. aureus (MRSA). Rate of occurrence of MRSA was more common among isolates from surgical wards (p < 0.001) compared to those from ENT ward. High level of multi-drug resistance (MDR) was detected more commonly among isolates from orthopedic ward than those from general surgical ward and patients with ear infection (p < 0.001). One of the isolate cultured from wound swab of a patient with surgical site infection from orthopedic ward was resistant to all of the 17 antimicrobials tested. CONCLUSION S. aureus isolates from patients in TASH exhibited resistance to majority of antimicrobials commonly employed for the treatment of staphylococcal infections which calls for urgent need of prudent use of antimicrobials and the need for implementation of effective infection control practices to hamper spread of MDR S. aureus.
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Affiliation(s)
- Sileshi Tadesse
- Yekatit 12 Hospital Medical College, P.O. Box157, Addis Ababa, Ethiopia
| | - Haile Alemayehu
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | - Admasu Tenna
- Department of Internal Medicine, School of Medicine, College of Health Sciences, Addis Ababa University, Churchill Avenue, P.O.Box 9086, Addis Ababa, Ethiopia
| | - Getachew Tadesse
- Department of Biomedical Sciences, College of Veterinary medicine and Agriculture, Addis Ababa University, P.O. Box 34, Debrezeit, Ethiopia
| | - Tefaye Sisay Tessema
- Institute of Biotechnology, College of natural and Computational sciences, Addis Ababa University, P.O. Box, 1176, Addis Ababa, Ethiopia
| | - Workineh Shibeshi
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Churchill Avenue, P.O. Box 9086, Addis Ababa, Ethiopia
| | - Tadesse Eguale
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
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19
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Zhang X, Wang L, Li R, Hou P, Zhang Y, Fang M, Hu B. Presence and characterization of Klebsiella pneumoniae
from the intestinal tract of diarrhoea patients. Lett Appl Microbiol 2018. [DOI: 10.1111/lam.12877] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- X. Zhang
- Tai'an Center for Disease Control and Prevention; Tai'an Shandong Province China
| | - L. Wang
- Laiwu Center for Disease Control and Prevention; Laiwu Shandong Province China
| | - R. Li
- Shandong Center for Disease Control and Prevention; Jinan Shandong Province China
| | - P. Hou
- Tai'an Center for Disease Control and Prevention; Tai'an Shandong Province China
| | - Y. Zhang
- Shandong Center for Disease Control and Prevention; Jinan Shandong Province China
| | - M. Fang
- Shandong Center for Disease Control and Prevention; Jinan Shandong Province China
| | - B. Hu
- Shandong Center for Disease Control and Prevention; Jinan Shandong Province China
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20
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Fisher EL, Otto M, Cheung GYC. Basis of Virulence in Enterotoxin-Mediated Staphylococcal Food Poisoning. Front Microbiol 2018; 9:436. [PMID: 29662470 PMCID: PMC5890119 DOI: 10.3389/fmicb.2018.00436] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/26/2018] [Indexed: 12/17/2022] Open
Abstract
The Staphylococcus aureus enterotoxins are a superfamily of secreted virulence factors that share structural and functional similarities and possess potent superantigenic activity causing disruptions in adaptive immunity. The enterotoxins can be separated into two groups; the classical (SEA-SEE) and the newer (SEG-SElY and counting) enterotoxin groups. Many members from both these groups contribute to the pathogenesis of several serious human diseases, including toxic shock syndrome, pneumonia, and sepsis-related infections. Additionally, many members demonstrate emetic activity and are frequently responsible for food poisoning outbreaks. Due to their robust tolerance to denaturing, the enterotoxins retain activity in food contaminated previously with S. aureus. The genes encoding the enterotoxins are found mostly on a variety of different mobile genetic elements. Therefore, the presence of enterotoxins can vary widely among different S. aureus isolates. Additionally, the enterotoxins are regulated by multiple, and often overlapping, regulatory pathways, which are influenced by environmental factors. In this review, we also will focus on the newer enterotoxins (SEG-SElY), which matter for the role of S. aureus as an enteropathogen, and summarize our current knowledge on their prevalence in recent food poisoning outbreaks. Finally, we will review the current literature regarding the key elements that govern the complex regulation of enterotoxins, the molecular mechanisms underlying their enterotoxigenic, superantigenic, and immunomodulatory functions, and discuss how these activities may collectively contribute to the overall manifestation of staphylococcal food poisoning.
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Affiliation(s)
- Emilie L Fisher
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Gordon Y C Cheung
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
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21
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Convergent Evolution Driven by Rifampin Exacerbates the Global Burden of Drug-Resistant Staphylococcus aureus. mSphere 2018; 3:mSphere00550-17. [PMID: 29404415 PMCID: PMC5784246 DOI: 10.1128/msphere.00550-17] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/23/2017] [Indexed: 11/20/2022] Open
Abstract
Mutations in the beta-subunit of bacterial RNA polymerase (RpoB) cause resistance to rifampin (Rifr), a critical antibiotic for treatment of multidrug-resistant Staphylococcus aureus. In vitro studies have shown that RpoB mutations confer decreased susceptibility to other antibiotics, but the clinical relevance is unknown. Here, by analyzing 7,099 S. aureus genomes, we demonstrate that the most prevalent RpoB mutations promote clinically relevant phenotypic plasticity resulting in the emergence of stable S. aureus lineages, associated with increased risk of therapeutic failure through generation of small-colony variants (SCVs) and coresistance to last-line antimicrobial agents. We found eight RpoB mutations that accounted for 93% (469/505) of the total number of Rifr mutations. The most frequently selected amino acid substitutions affecting residue 481 (H481N/Y) were associated with worldwide expansions of Rifr clones spanning decades. Recreating the H481N/Y mutations confirmed no impact on S. aureus growth, but the H481N mutation promoted the emergence of a subpopulation of stable Rifr SCVs with reduced susceptibility to vancomycin and daptomycin. Recreating the other frequent RpoB mutations showed similar impacts on resistance to these last-line agents. We found that 86% of all Rifr isolates in our global sample carried the mutations promoting cross-resistance to vancomycin and 52% to both vancomycin and daptomycin. As four of the most frequent RpoB mutations confer only low-level Rifr, equal to or below some international breakpoints, we recommend decreasing these breakpoints and reconsidering the appropriate use of rifampin to reduce the fixation and spread of these clinically deleterious mutations. IMPORTANCE Increasing antibiotic resistance in the major human pathogen Staphylococcus aureus is threatening the ability to treat patients with these infections. Recent laboratory studies suggest that mutations in the gene commonly associated with rifampin resistance may also impact susceptibility to other last-line antibiotics in S. aureus; however, the overall frequency and clinical impact of these mutations are unknown. By mining a global collection of clinical S. aureus genomes and by mutagenesis experiments, this work reveals that common rifampin-induced rpoB mutations promote phenotypic plasticity that has led to the global emergence of stable, multidrug-resistant S. aureus lineages that are associated with increased risk of therapeutic failure through coresistance to other last-line antimicrobials. We recommend decreasing susceptibility breakpoints for rifampin to allow phenotypic detection of critical rpoB mutations conferring low resistance to rifampin and reconsidering the appropriate use of rifampin to reduce the fixation and spread of these deleterious mutations globally.
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Kant S, Asthana S, Missiakas D, Pancholi V. A novel STK1-targeted small-molecule as an "antibiotic resistance breaker" against multidrug-resistant Staphylococcus aureus. Sci Rep 2017; 7:5067. [PMID: 28698584 PMCID: PMC5505960 DOI: 10.1038/s41598-017-05314-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 06/15/2017] [Indexed: 01/28/2023] Open
Abstract
Ser/Thr protein kinase (STK1) plays a critical role in cell wall biosynthesis of and drug resistance in methicillin-resistant Staphylococcus aureus (MRSA). MRSA strains lacking STK1 become susceptible to failing cephalosporins, such as Ceftriaxone and Cefotaxime. STK1, despite being nonessential protein for MRSA survival, it can serve as an important therapeutic agent for combination therapy. Here, we report a novel small molecule quinazoline compound, Inh2-B1, which specifically inhibits STK1 activity by directly binding to its ATP-binding catalytic domain. Functional analyses encompassing in vitro growth inhibition of MRSA, and in vivo protection studies in mice against the lethal MRSA challenge indicated that at high concentration neither Inh2-B1 nor Ceftriaxone or Cefotaxime alone was able to inhibit the growth of bacteria or protect the challenged mice. However, the growth of MRSA was inhibited, and a significant protection in mice against the bacterial challenge was observed at a micromolar concentration of Ceftriaxone or Cefotaxime in the presence of Inh2-B1. Cell-dependent minimal to no toxicity of Inh2-B1, and its abilities to down-regulate cell wall hydrolase genes and disrupt the biofilm formation of MRSA clearly indicated that Inh2-B1 serves as a therapeutically important “antibiotic-resistance-breaker,” which enhances the bactericidal activity of Ceftriaxone/Cefotaxime against highly pathogenic MRSA infection.
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Affiliation(s)
- Sashi Kant
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Shailendra Asthana
- Drug Discovery Research Center, Translational Health Science and Technology Institute, Faridabad-Gurgaon Expressway, Haryana, India
| | | | - Vijay Pancholi
- Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, USA.
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23
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Geisinger E, Isberg RR. Interplay Between Antibiotic Resistance and Virulence During Disease Promoted by Multidrug-Resistant Bacteria. J Infect Dis 2017; 215:S9-S17. [PMID: 28375515 DOI: 10.1093/infdis/jiw402] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Diseases caused by antibiotic-resistant bacteria in hospitals are the outcome of complex relationships between several dynamic factors, including bacterial pathogenicity, the fitness costs of resistance in the human host, and selective forces resulting from interventions such as antibiotic therapy. The emergence and fate of mutations that drive antibiotic resistance are governed by these interactions. In this review, we will examine how different forms of antibiotic resistance modulate bacterial fitness and virulence potential, thus influencing the ability of pathogens to evolve in the context of nosocomial infections. We will focus on 3 important multidrug-resistant pathogens that are notoriously problematic in hospitals: Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. An understanding of how antibiotic resistance mutations shape the pathobiology of multidrug-resistant infections has the potential to drive novel strategies that can control the development and spread of drug resistance.
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Affiliation(s)
- Edward Geisinger
- Howard Hughes Medical Institute, and.,Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Ralph R Isberg
- Howard Hughes Medical Institute, and.,Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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24
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Surface analysis of nitrogen plasma-treated C 60/PS nanocomposite films for antibacterial activity. J Biol Phys 2017; 43:211-224. [PMID: 28474135 DOI: 10.1007/s10867-017-9447-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/24/2017] [Indexed: 01/05/2023] Open
Abstract
The influence of N2 plasma on the antibacterial properties of polystyrene/fullerene (C60/PS) nanocomposite films with two concentrations is investigated. A comparison is made between the surface characteristics of the films before and after plasma irradiation for different time intervals. The alterations induced on the surface of the films after treatment are analyzed by contact angle and surface energy measurements, FTIR spectroscopy, and atomic force microscopy. The antibacterial properties, growth, biofilm formation, and adhesion of the nanocomposite films against two multidrug-resistant bacterial strains, Staphylococcus aureus KT337489 and Pseudomonas aeruginosa KT337488, are investigated before and after plasma irradiation. The results indicate that P. aeruginosa is more sensitive to treatment than S. aureus as well as an enhancement of the anti-adhesion of both strains to treated surfaces through exposure.
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25
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Rasigade JP. Catching the evader: Can monoclonal antibodies interfere with Staphylococcus aureus immune escape? Virulence 2017; 9:1-4. [PMID: 28441093 PMCID: PMC5955477 DOI: 10.1080/21505594.2017.1320012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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26
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Why new antibiotics are not obviously useful now. Int J Antimicrob Agents 2017; 49:549-553. [DOI: 10.1016/j.ijantimicag.2016.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/08/2016] [Accepted: 11/12/2016] [Indexed: 01/22/2023]
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27
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Cameron DR, Lin YH, Trouillet-Assant S, Tafani V, Kostoulias X, Mouhtouris E, Skinner N, Visvanathan K, Baines SL, Howden B, Monk IR, Laurent F, Stinear TP, Howden BP, Peleg AY. Vancomycin-intermediate Staphylococcus aureus isolates are attenuated for virulence when compared with susceptible progenitors. Clin Microbiol Infect 2017; 23:767-773. [PMID: 28396035 DOI: 10.1016/j.cmi.2017.03.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Vancomycin-intermediate Staphylococcus aureus (VISA) is associated with genetic changes that may also impact upon pathogenicity. In the current study, we compared the virulence of clinical VISA strains with their isogenic vancomycin-susceptible progenitors (VSSA). METHODS Production of the critical virulence protein, α toxin, was assessed using Western blot analysis and was correlated to agr activity using a bioluminescent agr-reporter. Cytotoxicity and intracellular persistence were compared ex vivo for VSSA and VISA within non-professional phagocytes (NPP). Virulence and host immune responses were further explored in vivo using a murine model of bacteraemia. RESULTS VISA isolates produced up to 20-fold less α toxin compared with VSSA, and this was corroborated by either loss of agr activity due to agr mutation, or altered agr activity in the absence of mutation. VISA were less cytotoxic towards NPP and were associated with enhanced intracellular persistence, suggesting that NPP may act as a reservoir for VISA. Infection with VSSA strains produced higher mortality in a murine bacteraemia model (≥90% 7-day mortality) compared with infection with VISA isolates (20% to 50%, p <0.001). Mice infected with VISA produced a dampened immune response (4.6-fold reduction in interleukin-6, p <0.001) and persistent organ bacterial growth was observed for VISA strains out to 7 days. CONCLUSIONS These findings highlight the remarkable adaptability of S. aureus, whereby, in addition to having reduced antibiotic susceptibility, VISA alter the expression of pathogenic factors to circumvent the host immune response to favour persistent infection over acute virulence.
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Affiliation(s)
- D R Cameron
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Australia
| | - Y-H Lin
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute of Infection & Immunity, Australia
| | - S Trouillet-Assant
- Department of Microbiology, French National Reference Centre for Staphylococci, Hospices Civils de Lyon, International Centre of Infectiology Research, France
| | - V Tafani
- Department of Microbiology, French National Reference Centre for Staphylococci, Hospices Civils de Lyon, International Centre of Infectiology Research, France
| | - X Kostoulias
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Australia
| | - E Mouhtouris
- Department of Surgery, The University of Melbourne, Australia
| | - N Skinner
- Department of Medicine, The University of Melbourne, Australia
| | - K Visvanathan
- Department of Medicine, The University of Melbourne, Australia
| | - S L Baines
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute of Infection & Immunity, Australia
| | - B Howden
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute of Infection & Immunity, Australia
| | - I R Monk
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute of Infection & Immunity, Australia
| | - F Laurent
- Department of Microbiology, French National Reference Centre for Staphylococci, Hospices Civils de Lyon, International Centre of Infectiology Research, France
| | - T P Stinear
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute of Infection & Immunity, Australia
| | - B P Howden
- Department of Microbiology and Immunology, The University of Melbourne at the Doherty Institute of Infection & Immunity, Australia; Infectious Diseases and Microbiology Departments, Austin Health, Australia.
| | - A Y Peleg
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Australia; Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Australia.
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28
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Cameron DR, Jiang JH, Kostoulias X, Foxwell DJ, Peleg AY. Vancomycin susceptibility in methicillin-resistant Staphylococcus aureus is mediated by YycHI activation of the WalRK essential two-component regulatory system. Sci Rep 2016; 6:30823. [PMID: 27600558 PMCID: PMC5013275 DOI: 10.1038/srep30823] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/09/2016] [Indexed: 02/01/2023] Open
Abstract
The treatment of infections caused by methicillin-resistant Staphylococcus aureus is complicated by the emergence of strains with intermediate-level resistance to vancomycin (termed VISA). We have characterised a molecular pathway involved in the in vivo evolution of VISA mediated by the regulatory proteins YycH and YycI. In contrast to their function in other bacterial species, we report a positive role for these auxiliary proteins in regulation of the two-component regulator WalRK. Transcriptional profiling of yycH and yycI deletion mutants revealed downregulation of the ‘WalRK regulon’ including cell wall hydrolase genes atlA and sle1, with functional autolysis assays supporting these data by showing an impaired autolytic phenotype for each deletion strain. Using bacterial-two hybrid assays, we showed that YycH and YycI interact, and that YycHI also interacts with the sensor kinase WalK, forming a ternary protein complex. Mutation to YycH or YycI associated with clinical VISA strains had a deleterious impact on the YycHI/WalK complex, suggesting that the interaction is important for the regulation of WalRK. Taken together, we have described a novel antibiotic resistance strategy for the human pathogen S. aureus, whereby YycHI mutations are selected for in vivo leading to reduced WalRK activation, impaired cell wall turnover and ultimately reduced vancomycin efficacy.
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Affiliation(s)
- David R Cameron
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Jhih-Hang Jiang
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Xenia Kostoulias
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Daniel J Foxwell
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Melbourne, Australia.,Department of Infectious Diseases, Alfred Hospital and Monash University, Melbourne, Australia
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29
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Matsumoto Y, Yasukawa J, Ishii M, Hayashi Y, Miyazaki S, Sekimizu K. A critical role of mevalonate for peptidoglycan synthesis in Staphylococcus aureus. Sci Rep 2016; 6:22894. [PMID: 26961421 PMCID: PMC4790635 DOI: 10.1038/srep22894] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/23/2016] [Indexed: 11/16/2022] Open
Abstract
3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase, a mevalonate synthetase, is required for the growth of Staphylococcus aureus. However, the essential role of the enzyme in cell growth has remained unclear. Here we show that three mutants possessed single-base substitutions in the mvaA gene, which encodes HMG-CoA reductase, show a temperature-sensitive phenotype. The phenotype was suppressed by the addition of mevalonate or farnesyl diphosphate, which is a product synthesized from mevalonate. Farnesyl diphosphate is a precursor of undecaprenyl phosphate that is required for peptidoglycan synthesis. The rate of peptidoglycan synthesis was decreased in the mvaA mutants under the non-permissive conditions and the phenotype was suppressed by the addition of mevalonate. HMG-CoA reductase activities of mutant MvaA proteins in the temperature sensitive mutants were lower than that of wild-type MvaA protein. Our findings from genetic and biochemical analyses suggest that mevalonate produced by HMG-CoA reductase is required for peptidoglycan synthesis for S. aureus cell growth.
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Affiliation(s)
- Yasuhiko Matsumoto
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 111-0033, Japan
| | - Jyunichiro Yasukawa
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 111-0033, Japan
| | - Masaki Ishii
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 111-0033, Japan
| | - Yohei Hayashi
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 111-0033, Japan
| | - Shinya Miyazaki
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 111-0033, Japan
| | - Kazuhisa Sekimizu
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 111-0033, Japan
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30
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Li B, Ge M, Zhang Y, Wang L, Ibrahim M, Wang Y, Sun G, Chen G. New insights into virulence mechanisms of rice pathogen Acidovorax avenae subsp. avenae strain RS-1 following exposure to ß-lactam antibiotics. Sci Rep 2016; 6:22241. [PMID: 26915352 PMCID: PMC4768089 DOI: 10.1038/srep22241] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 02/10/2016] [Indexed: 12/24/2022] Open
Abstract
Recent research has shown that pathogen virulence can be altered by exposure to antibiotics, even when the growth rate is unaffected. Investigating this phenomenon provides new insights into understanding the virulence mechanisms of bacterial pathogens. This study investigates the phenotypic and transcriptomic responses of the rice pathogenic bacterium Acidovorax avenae subsp. avenae (Aaa) strain RS-1 to ß-lactam antibiotics especially Ampicillin (Amp). Our results indicate that exposure to Amp does not influence bacterial growth and biofilm formation, but alters the virulence, colonization capacity, composition of extracellular polymeric substances and secretion of Type VI secretion system (T6SS) effector Hcp. This attenuation in virulence is linked to unique or differential expression of known virulence-associated genes based on genome-wide transcriptomic analysis. The reliability of expression data generated by RNA-Seq was verified with quantitative real-time PCR of 21 selected T6SS genes, where significant down-regulation in expression of hcp gene, corresponding to the reduction in secretion of Hcp, was observed under exposure to Amp. Hcp is highlighted as a potential target for Amp, with similar changes observed in virulence-associated phenotypes between exposure to Amp and mutation of hcp gene. In addition, Hcp secretion is reduced in knockout mutants of 4 differentially expressed T6SS genes.
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Affiliation(s)
- Bin Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Mengyu Ge
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Yang Zhang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Li Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Muhammad Ibrahim
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.,Department of Biosciences, COMSATS Institute of Information technology Sahiwal Campus, Sahiwal, Pakistan
| | - Yanli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Plant Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Plant Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Gongyou Chen
- School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China
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Vittecoq M, Godreuil S, Prugnolle F, Durand P, Brazier L, Renaud N, Arnal A, Aberkane S, Jean-Pierre H, Gauthier-Clerc M, Thomas F, Renaud F. Antimicrobial resistance in wildlife. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12596] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marion Vittecoq
- Centre de recherche de la Tour du Valat; Arles France
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - Sylvain Godreuil
- Département de Bactériologie-Virologie; Centre Hospitalier Régional Universitaire (CHRU) de Montpellier; Montpellier France
- Université de Montpellier; Montpellier France
- U 1058; INSERM; Montpellier France
| | - Franck Prugnolle
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - Patrick Durand
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - Lionel Brazier
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - Nicolas Renaud
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - Audrey Arnal
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - Salim Aberkane
- Département de Bactériologie-Virologie; Centre Hospitalier Régional Universitaire (CHRU) de Montpellier; Montpellier France
- U 1058; INSERM; Montpellier France
| | - Hélène Jean-Pierre
- Département de Bactériologie-Virologie; Centre Hospitalier Régional Universitaire (CHRU) de Montpellier; Montpellier France
- Université de Montpellier; Montpellier France
- UMR 5119 (UM2, CNRS, IRD, IFREMER, UM); Equipe Pathogènes et Environnements; U.F.R. Pharmacie; Montpellier France
| | - Michel Gauthier-Clerc
- Centre de recherche de la Tour du Valat; Arles France
- Département Chrono-Environnement; UMR UFC/CNRS 6249 USC INRA; Université de Franche-Comté; Besançon France
| | - Frédéric Thomas
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
| | - François Renaud
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université de Montpellier; Montpellier France
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32
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De la Calle C, Morata L, Cobos-Trigueros N, Martinez JA, Cardozo C, Mensa J, Soriano A. Staphylococcus aureus bacteremic pneumonia. Eur J Clin Microbiol Infect Dis 2016; 35:497-502. [PMID: 26780692 DOI: 10.1007/s10096-015-2566-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/21/2015] [Indexed: 01/21/2023]
Abstract
Staphylococcus aureus bacteremic pneumonia is an uncommon cause of hospitalization, with a high mortality rate. However, published reports are scarce and have included a small number of cases. All patients with S. aureus bacteremic pneumonia were prospectively collected in our institution from 2000 to 2014, and a retrospective revision was performed to identify risk factors associated with methicillin resistance and to update the mortality of this entity. A total of 98 patients were admitted: 57.1 % were due to methicillin-susceptible S. aureus (MSSA) and 42.8 % due to methicillin-resistant S. aureus (MRSA). In 40 patients (40.8 %), the infection was community acquired. Thirteen were ventilator-associated pneumonia episodes. The most frequent comorbidities were chronic lung disease (34.7 %), chronic renal failure (31.6 %), diabetes mellitus (29.6 %), and cardiovascular disease (31.6 %). Septic shock was present in 46 patients (46.9 %). The 30-day mortality was 46.9 %. MRSA infections occurred in older patients, more frequently with cardiovascular diseases, and they had received antibiotic treatment in the previous month more often than MSSA-infected patients. Patients with infection due to MSSA presented more frequently with septic shock, but they received more frequently appropriate empirical antibiotic therapy than patients with MRSA pneumonia (96 % vs. 38.1 %), and no differences in mortality were observed between both groups. In conclusion, S. aureus bacteremic pneumonia is a severe infection that, nowadays, affects people with comorbidities and the mortality is still high.
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Affiliation(s)
- C De la Calle
- Department of Infectious Diseases Hospital Clínic, Barcelona, Spain.
| | - L Morata
- Department of Infectious Diseases Hospital Clínic, Barcelona, Spain
| | | | - J A Martinez
- Department of Infectious Diseases Hospital Clínic, Barcelona, Spain
| | - C Cardozo
- Department of Infectious Diseases Hospital Clínic, Barcelona, Spain
| | - J Mensa
- Department of Infectious Diseases Hospital Clínic, Barcelona, Spain
| | - A Soriano
- Department of Infectious Diseases Hospital Clínic, Barcelona, Spain
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Stepwise decrease in daptomycin susceptibility in clinical Staphylococcus aureus isolates associated with an initial mutation in rpoB and a compensatory inactivation of the clpX gene. Antimicrob Agents Chemother 2015; 59:6983-91. [PMID: 26324273 DOI: 10.1128/aac.01303-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/25/2015] [Indexed: 12/16/2022] Open
Abstract
Daptomycin is a lipopeptide antibiotic used clinically for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. The emergence of daptomycin-nonsusceptible S. aureus isolates during therapy is often associated with multiple genetic changes; however, the relative contributions of these changes to resistance and other phenotypic changes usually remain unclear. The present study was undertaken to investigate this issue using a genetically characterized series of four isogenic clinical MRSA strains derived from a patient with bacteremia before and during daptomycin treatment. The first strain obtained after daptomycin therapy carried a single-nucleotide polymorphism (SNP) in rpoB (RpoB A477D) that decreased susceptibility not only to daptomycin but also to vancomycin, β-lactams, and rifampin. Furthermore, the rpoB mutant exhibited pleiotropic phenotypes, including increased cell wall thickness, reduced expression of virulence traits, induced expression of the stress-associated transcriptional regulator Spx, and slow growth. A subsequently acquired loss-of-function mutation in clpX partly alleviated the growth defect conferred by the rpoB mutation without changing antibiotic susceptibility. The final isolate acquired three additional mutations, including an SNP in mprF (MprF S295L) known to confer daptomycin nonsusceptibility, and accordingly, this isolate was the only daptomycin-nonsusceptible strain of this series. Interestingly, in this isolate, the cell wall had regained the same thickness as that of the parental strain, while the level of transcription of the vraSR (cell wall stress regulator) was increased. In conclusion, this study illustrates how serial genetic changes selected in vivo contribute to daptomycin nonsusceptibility, growth fitness, and virulence traits.
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Prevalence of Virulence Factors and Drug Resistance in Clinical Isolates of Enterococci: A Study from North India. J Pathog 2015; 2015:692612. [PMID: 26366302 PMCID: PMC4561117 DOI: 10.1155/2015/692612] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/06/2015] [Accepted: 08/09/2015] [Indexed: 11/17/2022] Open
Abstract
Along with emergence of multidrug resistance, presence of several virulence factors in enterococci is an emerging concept. This study was undertaken to determine the prevalence of various virulence factors phenotypically and genotypically in enterococci and study their association with multidrug resistance. A total of 310 enterococcal isolates were studied, comprising 155 E. faecium and 155 E. faecalis. Antimicrobial susceptibility testing was done by disc diffusion and agar dilution method. Hemolysin, gelatinase, biofilm production, and haemagglutination were detected phenotypically and presence of virulence genes, namely, asa1, gelE, cylA, esp, and hyl, was detected by multiplex PCR. Of the total, 47.41% isolates were high level gentamicin resistant (HLGRE) and 7.09% were vancomycin resistant (VRE). All the virulence traits studied were found in varying proportions, with majority in E. faecalis (p > 0.05). Strong biofilm producers possessed either asa1 or gelE gene. gelE silent gene was detected in 41.37% (12/29). However, increase in resistance was associated with significant decrease in expression or acquisition of virulence genes. Further, acquisition of vancomycin resistance was the significant factor responsible for the loss of virulence traits. Though it is presumed that increased drug resistance correlates with increased virulence, acquisition of vancomycin resistance might be responsible for reduced expression of virulence traits to meet the “biological cost” relating to VRE.
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Hong J, Kim Y, Kim J, Heu S, Kim SR, Kim KP, Roh E. Genetic Diversity and Antibiotic Resistance Patterns of Staphylococcus Aureus Isolated from Leaf Vegetables in Korea. J Food Sci 2015; 80:M1526-31. [PMID: 26018816 DOI: 10.1111/1750-3841.12909] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 04/20/2015] [Indexed: 11/29/2022]
Abstract
Staphylococcus aureus is an important foodborne pathogen on global basis. The current study investigated the genetic patterns in S. aureus isolates from leaf vegetables (n = 53). Additional isolates from livestock (n = 31) and humans (n = 27) were compared with the leaf vegetable isolates. Genes associated with toxins, antibiotic resistance, and pulsed-field gel electrophoresis (PFGE) patterns were analyzed. At least 1 enterotoxin-encoding gene (sea, seb, sec, sed, and see) was detected in 11 of 53 (20.75%) leaf vegetable isolates. When the agr (accessory gene regulator) grouping was analyzed, agr II was the major group, whereas agr IV was not present in leaf vegetable isolates. All S. aureus isolates from leaf vegetables were resistant to more than one of the antibiotics tested. Nineteen of 53 (35.85%) isolates from leaf vegetables exhibited multidrug-resistance, and 11 of these were MRSA (methicillin-resistant S. aureus). A dendrogram displaying the composite types of S. aureus isolates from 3 origins was generated based on the combination of the toxin genes, agr genes, antibiotic resistance, and PFGE patterns. The isolates could be clustered into 8 major composite types. The genetic patterns of S. aureus isolates from leaf vegetables and humans were similar, whereas those from livestock had unique patterns. This suggests some S. aureus isolates from leaf vegetables to be of human origin.
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Affiliation(s)
- Jisoo Hong
- Microbial Safety Team, Natl. Academy of Agricultural Science, RDA, Wanju 565-851, Republic of Korea
| | - Yangkyun Kim
- Microbial Safety Team, Natl. Academy of Agricultural Science, RDA, Wanju 565-851, Republic of Korea
| | - Jonguk Kim
- Microbial Safety Team, Natl. Academy of Agricultural Science, RDA, Wanju 565-851, Republic of Korea
| | - Sunggi Heu
- Microbial Safety Team, Natl. Academy of Agricultural Science, RDA, Wanju 565-851, Republic of Korea
| | - Se-ri Kim
- Microbial Safety Team, Natl. Academy of Agricultural Science, RDA, Wanju 565-851, Republic of Korea
| | - Kwang-Pyo Kim
- Dept. of Food Science, School of Agriculture and Life Sciences, Chonbuk Natl. Univ, Jeonju, Chonbuk 561-756, Republic of Korea
| | - Eunjung Roh
- Microbial Safety Team, Natl. Academy of Agricultural Science, RDA, Wanju 565-851, Republic of Korea
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Tiwari K, Banerjee T, Filgona J, Anupurba S. Study of virulence factors in association with antimicrobial resistance amongst urinary isolates of enterococci. Indian J Med Microbiol 2015; 33:455-6. [PMID: 26068361 DOI: 10.4103/0255-0857.158602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
| | | | | | - S Anupurba
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Gao D, Lietman TM, Porco TC. Antibiotic resistance as collateral damage: the tragedy of the commons in a two-disease setting. Math Biosci 2015; 263:121-32. [PMID: 25726716 PMCID: PMC4414057 DOI: 10.1016/j.mbs.2015.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 01/21/2023]
Abstract
We propose a simple two-disease epidemic model where one disease exhibits only a drug-sensitive strain, while the other exhibits both drug-sensitive and drug-resistant strains. Treatment for the first disease may select for resistance in the other. We model antibiotic use as a mathematical game through the study of individual incentives and community welfare. The basic reproduction number is derived and the existence and local stability of the model equilibria are analyzed. When the force of infection of each disease is unaffected by the presence of the other, we find that there is a conflict of interest between individual and community, known as a tragedy of the commons, under targeted treatment toward persons infected by the single strain disease, but there is no conflict under mass treatment. However, we numerically show that individual and social incentive to use antibiotics may show disaccord under mass treatment if the restriction on the transmission ability of the dually infected people is removed, or drug resistant infection is worse than drug sensitive infection, or the uninfected state has a comparative disutility over the infected states.
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Affiliation(s)
- Daozhou Gao
- Francis I. Proctor Foundation for Research in Ophthalmology, University of California, San Francisco, CA, USA.
| | - Thomas M Lietman
- Francis I. Proctor Foundation for Research in Ophthalmology, University of California, San Francisco, CA, USA; Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA; Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Travis C Porco
- Francis I. Proctor Foundation for Research in Ophthalmology, University of California, San Francisco, CA, USA; Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA; Department of Ophthalmology, University of California, San Francisco, CA, USA.
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Arroliga AC, Velazco JF, Midturi JK, Ghamande SA. Back to the future: α-hemolysin activity on blood agar to predict ventilator-associated pneumonia caused by Staphylococcus aureus. Am J Respir Crit Care Med 2015; 190:1086-8. [PMID: 25398106 DOI: 10.1164/rccm.201410-1886ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Southern TR, VanSchooneveld TC, Bannister DL, Brown TL, Crismon AS, Buss SN, Iwen PC, Fey PD. Implementation and performance of the BioFire FilmArray® Blood Culture Identification panel with antimicrobial treatment recommendations for bloodstream infections at a midwestern academic tertiary hospital. Diagn Microbiol Infect Dis 2014; 81:96-101. [PMID: 25488272 DOI: 10.1016/j.diagmicrobio.2014.11.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/28/2014] [Accepted: 11/08/2014] [Indexed: 10/24/2022]
Abstract
The FilmArray® Blood Culture Identification (BCID) panel was recently implemented at a midwestern academic tertiary care hospital to provide rapid identification (ID) of common pathogens from positive blood cultures. This study evaluated the clinical performance of the BCID panel compared to culture-based ID methods. One hundred thirty-eight monomicrobial and 8 polymicrobial blood cultures were evaluated during the 30-day study resulting in the ID of 152 total organisms by culture with 115 organisms correctly identified using the BCID panel. The BCID panel had sensitivities of 80.4% (115/152) for all organisms identified during the study and 94.6% (115/122) when considering only on-panel organisms. BCID panel specificity was 100%. Implementation of the BCID panel was coupled with the development of empiric therapy recommendations for bloodstream infections by the antimicrobial stewardship team. Based on this study, the FilmArray® BCID panel is a rapid and reliable test for the detection of common bloodstream pathogens, and therapeutic decisions can be based upon panel results.
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Affiliation(s)
- Timothy R Southern
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA; Nebraska Public Health Laboratory, Omaha, NE, USA.
| | - Trevor C VanSchooneveld
- Division of Infectious Disease, Department of Internal Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Dianna L Bannister
- Clinical Microbiology Laboratory, The Nebraska Medical Center, Omaha, NE, USA
| | - TeAnne L Brown
- Clinical Microbiology Laboratory, The Nebraska Medical Center, Omaha, NE, USA
| | - Amy S Crismon
- Clinical Microbiology Laboratory, The Nebraska Medical Center, Omaha, NE, USA
| | - Sarah N Buss
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA; Nebraska Public Health Laboratory, Omaha, NE, USA
| | - Peter C Iwen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA; Nebraska Public Health Laboratory, Omaha, NE, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
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Fätkenheuer G, Kaasch AJ. How deadly is meticillin-resistant Staphylococcus aureus? THE LANCET. INFECTIOUS DISEASES 2014; 14:905-7. [PMID: 25185459 DOI: 10.1016/s1473-3099(14)70904-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Gerd Fätkenheuer
- Department I of Internal Medicine, University Hospital of Cologne, Germany; German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Cologne, Germany.
| | - Achim J Kaasch
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany
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Gardete S, Tomasz A. Mechanisms of vancomycin resistance in Staphylococcus aureus. J Clin Invest 2014; 124:2836-40. [PMID: 24983424 DOI: 10.1172/jci68834] [Citation(s) in RCA: 315] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Vancomycin is a glycopeptide antibiotic used for the treatment of Gram-positive bacterial infections. Traditionally, it has been used as a drug of last resort; however, clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased susceptibility to vancomycin (vancomycin intermediate-resistant S. aureus [VISA]) and more recently with high-level vancomycin resistance (vancomycin-resistant S. aureus [VRSA]) have been described in the clinical literature. The rare VRSA strains carry transposon Tn1546, acquired from vancomycin-resistant Enterococcus faecalis, which is known to alter cell wall structure and metabolism, but the resistance mechanisms in VISA isolates are less well defined. Herein, we review selected mechanistic aspects of resistance in VISA and summarize biochemical studies on cell wall synthesis in a VRSA strain. Finally, we recapitulate a model that integrates common mechanistic features of VRSA and VISA strains and is consistent with the mode of action of vancomycin.
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Singh R, Ray P. Quorum sensing-mediated regulation of staphylococcal virulence and antibiotic resistance. Future Microbiol 2014; 9:669-81. [DOI: 10.2217/fmb.14.31] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
ABSTRACT: Accessory gene regulator (agr)-mediated quorum sensing plays a central role in staphylococcal pathogenesis. It primarily upregulates secreted virulence factors and downregulates cell surface proteins, thereby governing invasiveness of staphylococci and cell dispersal from biofilms. Except for α- and β-PSMs, which are directly controlled by AgrA, the effector functions of agr are primarily mediated by RNAIII, a regulatory RNA encoded by this operon. agr phenotype and expression considerably influence the chronicity of an infection. It has also been linked with altered susceptibility of Staphylococcus aureus against antibiotics. Four classes of S. aureus and Staphylococcus epidermidis AIPs exist based on sequence variation, and lead to inter-strain and species cross-inhibition. Certain agr classes have been associated with specific clonal complexes, disease syndromes and intermediate-susceptibility to glycopeptides. It is also being investigated as a prophylactic and therapeutic target. This article describes the presently available literature regarding the role of agr in S. aureus and S. epidermidis infections.
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Affiliation(s)
- Rachna Singh
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India
| | - Pallab Ray
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India
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Chua KYL, Howden BP, Jiang JH, Stinear T, Peleg AY. Population genetics and the evolution of virulence in Staphylococcus aureus. INFECTION GENETICS AND EVOLUTION 2013; 21:554-62. [PMID: 23628638 DOI: 10.1016/j.meegid.2013.04.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/22/2013] [Accepted: 04/22/2013] [Indexed: 11/18/2022]
Abstract
Staphylococcus aureus is one of the most important human pathogens, causing life-threatening infection in the community and hospital setting. The population genetics of S. aureus and the evolution of virulence is the focus of this review. We describe the various techniques in determining S. aureus population structure and discuss the insights gained from whole genome sequencing of various S. aureus strains. The emergence of community-acquired, methicillin-resistant S. aureus provides a framework for the discussion on evolution of virulence, and the role of horizontal gene transfer in the development of virulence and antibiotic resistance is explored. The knowledge generated from population genetics has the potential to inform strategies to assist in the prevention or treatment of this highly successful human pathogen.
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Affiliation(s)
- Kyra Y L Chua
- Department of Microbiology and Immunology, University of Melbourne, Victoria 3052, Australia; Austin Centre for Infection Research (ACIR), Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia; Microbiology Department, Austin Health, Heidelberg, Victoria 3084, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, University of Melbourne, Victoria 3052, Australia; Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia; Austin Centre for Infection Research (ACIR), Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia; Microbiology Department, Austin Health, Heidelberg, Victoria 3084, Australia
| | - Jhih-Hang Jiang
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Timothy Stinear
- Department of Microbiology and Immunology, University of Melbourne, Victoria 3052, Australia
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia; Department of Infectious Diseases, The Alfred Hospital, Melbourne, Victoria 3181, Australia; Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA, USA.
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Jansen KU, Girgenti DQ, Scully IL, Anderson AS. Vaccine review: "Staphyloccocus aureus vaccines: problems and prospects". Vaccine 2013; 31:2723-30. [PMID: 23624095 DOI: 10.1016/j.vaccine.2013.04.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/28/2013] [Accepted: 04/01/2013] [Indexed: 12/18/2022]
Abstract
Staphylococcus aureus is a leading cause of both healthcare- and community-associated infections globally. S. aureus exhibits diverse clinical presentations, ranging from benign carriage and superficial skin and soft tissue infections to deep wound and organ/space infections, biofilm-related prosthesis infections, life-threatening bacteremia and sepsis. This broad clinical spectrum, together with the high incidence of these disease manifestations and magnitude of the diverse populations at risk, presents a high unmet medical need and a substantial burden to the healthcare system. With the increasing propensity of S. aureus to develop resistance to essentially all classes of antibiotics, alternative strategies, such as prophylactic vaccination to prevent S. aureus infections, are actively being pursued in healthcare settings. Within the last decade, the S. aureus vaccine field has witnessed two major vaccine failures in phase 3 clinical trials designed to prevent S. aureus infections in either patients undergoing cardiothoracic surgery or patients with end-stage renal disease undergoing hemodialysis. This review summarizes the potential underlying reasons why these two approaches may have failed, and proposes avenues that may provide successful vaccine approaches to prevent S. aureus disease in the future.
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Howden BP, Peleg AY, Stinear TP. The evolution of vancomycin intermediate Staphylococcus aureus (VISA) and heterogenous-VISA. INFECTION GENETICS AND EVOLUTION 2013; 21:575-82. [PMID: 23567819 DOI: 10.1016/j.meegid.2013.03.047] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/20/2013] [Accepted: 03/29/2013] [Indexed: 12/01/2022]
Abstract
Resistance to new antimicrobials is generally recognized in Staphylococcus aureus soon after they are released for clinical use. In the case of vancomycin, which was first released in the 1950s, resistance was not reported until the mid 1990s, with the description of vancomycin-intermediate S. aureus (VISA), and heterogenous-VISA (hVISA). Unraveling the complex genetic and cell wall structural changes conferring low-level vancomycin resistance in S. aureus has proved challenging. However the recent advances in high throughput whole-genome sequencing has played a key role in determining the breadth of bacterial chromosomal changes linked with resistance. Diverse mutations in a small number of staphylococcal regulatory genes, in particular walKR, graRS, vraSR and rpoB, have been associated with hVISA and VISA. Only a small number of these mutations have been experimentally proven to confer the resistance phenotype and some of these only partially contribute to resistance. It also appears that the evolution of VISA from VSSA is a step-wise process. Transcriptomics studies, and analysis of host pathogen interactions, indicate that the evolution of vancomycin-susceptible S. aureus to VISA is associated not only with antibiotic resistance, but with other changes likely to promote persistent infection. These include predicted alterations in central metabolism, altered expression of virulence associated factors, attenuated virulence in vivo, and alterations in susceptibility to host innate immune responses, together with reduced susceptibility to other antibiotics. In fact, current data suggests that hVISA and VISA represent a bacterial evolutionary state favoring persistence in the face of not only antibiotics, but also the host environment. The additional knowledge of staphylococcal biology that has been uncovered during the study of hVISA and VISA is significant. The present review will detail the current understanding of the evolutionary process in the generation of hVISA and VISA, and explore the diverse additional changes that occur in these strains.
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Affiliation(s)
- Benjamin P Howden
- Austin Centre for Infection Research (ACIR), Infectious Diseases Department, Austin Health, Heidelberg, Victoria, Australia; Microbiology Department, Austin Health, Heidelberg, Victoria, Australia; Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Wellington Rd, Clayton, Victoria, Australia.
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Wellington Rd, Clayton, Victoria, Australia; Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Infectious Diseases, The Alfred Hospital, Melbourne, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Wellington Rd, Clayton, Victoria, Australia
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van Hal SJ, Fowler VG. Is it time to replace vancomycin in the treatment of methicillin-resistant Staphylococcus aureus infections? Clin Infect Dis 2013; 56:1779-88. [PMID: 23511300 DOI: 10.1093/cid/cit178] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
For more than 4 decades, vancomycin has been the antibiotic of choice for methicillin-resistant Staphylococcus aureus (MRSA) infections. Recently, infections due to isolates with high but susceptible vancomycin minimum inhibitory concentrations have been associated with additional treatment failures and patient mortality. These poorer outcomes may in part be explained by the inability of attaining appropriate vancomycin levels in these patients. However, assumptions that these poor outcomes are solely due to failure to achieve optimal serum levels of vancomycin are premature. The availability of effective alternatives further erodes the position of vancomycin as first-line therapy. The emergence of resistance and cost considerations, however, favor a more measured approach when using alternative antimicrobials. Collectively, the current available data suggest that the optimal therapy for MRSA infections remains unclear. In the absence of further data, the Infectious Diseases Society of America guidelines remain relevant and inform clinicians of best practice for treating patients with MRSA infections.
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Affiliation(s)
- Sebastiaan J van Hal
- Department of Microbiology and Infectious Diseases, Royal Prince Alfred Hospital, Camperdown, Sydney, Australia.
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Epidemiological Study on Staphylococcus aureus Isolates Reveals Inverse Relationship between Antibiotic Resistance and Virulence Repertoire. Indian J Microbiol 2013; 53:321-2. [PMID: 24426130 DOI: 10.1007/s12088-013-0357-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 01/10/2013] [Indexed: 01/25/2023] Open
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Han JH, Edelstein PH, Bilker WB, Lautenbach E. The effect of staphylococcal cassette chromosome mec (SCCmec) type on clinical outcomes in methicillin-resistant Staphylococcus aureus bacteremia. J Infect 2013; 66:41-7. [PMID: 22960078 PMCID: PMC3518704 DOI: 10.1016/j.jinf.2012.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/31/2012] [Accepted: 09/02/2012] [Indexed: 02/06/2023]
Abstract
OBJECTIVES The impact of staphylococcal cassette chromosome mec (SCCmec) type on mortality in methicillin-resistant Staphylococcus aureus (MRSA) infections remains unclear. The objective of this study was to determine the association between SCCmec type and mortality in MRSA bacteremia. METHODS A cohort study of patients who were hospitalized with MRSA bacteremia was conducted within a university health system. A multivariable logistic regression model was developed to evaluate the association of SCCmec type with 30-day in-hospital mortality. RESULTS Thirty-four of a total of 184 patients with MRSA bacteremia died, resulting in a mortality rate of 18.5%. Adjusted risk factors for 30-day mortality included APRDRG Risk of Mortality score (odds ratio [OR], 5.33; 95% confidence interval [CI], 2.28-12.4; P<0.001), white blood cell count (OR, 1.09; 95% CI, 1.03-1.15; P=0.002), and malignancy (OR, 3.25; 95% CI, 1.17-9.02; P=0.02). On multivariable analyses, SCCmec II was not significantly associated with mortality in patients with MRSA bacteremia (OR, 1.85; 95% CI, 0.69-4.92; P=0.22). CONCLUSIONS Mortality in MRSA bacteremia was independent of SCCmec type. SCCmec type II is most likely a marker for disease severity rather than a direct mediator of mortality. Further research is needed to elucidate the factors associated with poor clinical outcomes in MRSA infections.
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Affiliation(s)
- Jennifer H Han
- Division of Infectious Diseases, Department of Medicine, University of Pennsylvania School of Medicine, Hospital of the University of Pennsylvania, Philadelphia, 19104, USA.
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Kim R, Freeman J, Waldvogel-Thurlow S, Roberts S, Douglas R. The characteristics of intramucosal bacteria in chronic rhinosinusitis: a prospective cross-sectional analysis. Int Forum Allergy Rhinol 2012. [PMID: 23193001 DOI: 10.1002/alr.21117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND We have observed subepithelial bacterial microcolonies within the mucosa of patients with chronic rhinosinusitis (CRS). These were predominantly Staphylococcus aureus and did not appear to elicit a local inflammatory response. We hypothesized that these microcolonies had made adaptations allowing them to exist apparently undetected within the mucosa. We sought to determine whether the tissue colonies had genotypic or phenotypic variations from the surface bacteria. METHODS Mucosal swabs and tissue biopsies were taken from 31 patients with CRS undergoing functional endoscopic sinus surgery, and 9 with normal sinuses having transnasal pituitary surgery. Biopsied tissues were assessed histologically, by routine culture, and by culture techniques facilitating growth of small colony variants (SCVs). Genotypic typing compared isolates of S. aureus that were cultured from both swab and tissue samples. The activity of the accessory gene regulator (agr) gene, a global regulator of S. aureus virulence, was evaluated indirectly by determining the hemolytic activity of the colonies on blood agar. RESULTS SCVs were grown from 2 samples but these were found not to possess the nuc gene, specific to S. aureus. When S. aureus was recovered from both swab and mucosa, the genetic profiles were indistinguishable in all but 1 patient. All S. aureus cultured from mucosa demonstrated β-hemolysis, implying normal agr activity. CONCLUSION Intramucosal S. aureus are genetically closely related and phenotypically similar to surface S. aureus. Further studies are needed to explore the possible mechanisms by which intramucosal colonies become less immunogenic, and the role of the colonies in the pathophysiology of CRS.
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Affiliation(s)
- Raymond Kim
- Department of Surgery, The University of Auckland, Auckland, New Zealand
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Uskoković V, Desai TA. Phase composition control of calcium phosphate nanoparticles for tunable drug delivery kinetics and treatment of osteomyelitis. II. Antibacterial and osteoblastic response. J Biomed Mater Res A 2012; 101:1427-36. [PMID: 23115128 DOI: 10.1002/jbm.a.34437] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 08/20/2012] [Indexed: 12/24/2022]
Abstract
Osteomyelitis has been traditionally treated by the combination of long-term antibiotic therapies and surgical removal of diseased tissue. The multifunctional material was developed in this study with the aim to improve this therapeutic approach by: (a) enabling locally delivered and sustained release of antibiotics at a tunable rate, so as to eliminate the need for repetitive administration of systemically distributed antibiotics; and (b) controllably dissolving itself, so as to promote natural remineralization of the portion of bone lost to disease. We report hereby on the effect of previously synthesized calcium phosphates (CAPs) with tunable solubilities and drug release timescales on bacterial and osteoblastic cell cultures. All CAP powders exhibited satisfying antibacterial performance against Staphylococcus aureus, the main causative agent of osteomyelitis. Still, owing to its highest drug adsorption efficiency, the most bacteriostatically effective phase was amorphous CAP with the minimal inhibitory concentration of less than 1 mg/mL. At the same time, the positive cell response and osteogenic effect of the antibiotic-loaded CAP particles was confirmed in vitro for all the sparsely soluble CAP phases. Adsorption of the antibiotic onto CAP particles reversed the deleterious effect that the pure antibiotic exerted on the osteogenic activity of the osteoblastic cells. The simultaneous osteogenic and antimicrobial performance of the material developed in this study, altogether with its ability to exhibit sustained drug release, may favor its consideration as a material base for alternative therapeutic approaches to prolonged antibiotic administration and surgical debridement typically prescribed in the treatment of osteomyelitis.
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Affiliation(s)
- Vuk Uskoković
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158-2330, USA.
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