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Full-Genome Sequencing Identifies in the Genetic Background Several Determinants That Modulate the Resistance Phenotype in Methicillin-Resistant Staphylococcus aureus Strains Carrying the Novel mecC Gene. Antimicrob Agents Chemother 2017; 61:AAC.02500-16. [PMID: 28069659 DOI: 10.1128/aac.02500-16] [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: 11/28/2016] [Accepted: 01/01/2017] [Indexed: 12/30/2022] Open
Abstract
Most methicillin-resistant Staphylococcus aureus (MRSA) strains are resistant to beta-lactam antibiotics due to the presence of the mecA gene, encoding an extra penicillin-binding protein (PBP2A) that has low affinity for virtually all beta-lactam antibiotics. Recently, a new resistance determinant-the mecC gene-was identified in S. aureus isolates recovered from humans and dairy cattle. Although having typically low MICs to beta-lactam antibiotics, MRSA strains with the mecC determinant are also capable of expressing high levels of oxacillin resistance when in an optimal genetic background. In order to test the impact of extensive beta-lactam selection on the emergence of mecC-carrying strains with high levels of antibiotic resistance, we exposed the prototype mecC-carrying MRSA strain, LGA251, to increasing concentrations of oxacillin. LGA251 was able to rapidly adapt to high concentrations of oxacillin in growth medium. In such laboratory mutants with increased levels of oxacillin resistance, we identified mutations in genes with no relationship to the mecC regulatory system, indicating that the genetic background plays an important role in the establishment of the levels of oxacillin resistance. Our data also indicate that the stringent stress response plays a critical role in the beta-lactam antibiotic resistance phenotype of MRSA strains carrying the mecC determinant.
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52
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Icgen B. VanA-Type MRSA (VRSA) Emerged in Surface Waters. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 97:359-366. [PMID: 27216737 DOI: 10.1007/s00128-016-1827-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/12/2016] [Indexed: 06/05/2023]
Abstract
Due to the widespread occurrence of mecA-encoded methicillin resistance in Staphylococcus aureus (MRSA), treatment of staphylococcal infections is shifted to glycopeptide antibiotics like vancomycin and teicoplanin. The selective pressure of glycopeptides has eventually led to the emergence of staphylococci with increased resistance. Of great concern is vanA-encoded high level vancomycin and teicoplanin resistance in MRSA (VRSA). Therefore, this study aimed at investigating the occurrence of VRSA in surface waters. Out of 290, two staphylococcal isolates identified as MRSA Al11, Ba01, and one as MRS Co11 through 16S rRNA sequencing, also displayed high level resistance towards vancomycin and teicoplanin. These staphylococcal isolates were found to harbor vanA gene with sequence similarities of 99 %-100 % to the vanA gene extracted from vancomycin- and teicoplanin-resistant enterococcal (VRE) surface water isolates of Enterococcus faecalis Cr07, E07, Pb06 and E. faecium E330. High level glycopeptide resistance rendering protein encoded by the vanA gene, D-alanine-D-lactate ligase found in VRE, was also shown to be present in all vanA-type staphylococcal isolates through western blot. Current study elucidated that surface waters provide high potential for enterococcal vanA gene being transferred to MRSA, so called VRSA, and require special scientific consideration.
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Affiliation(s)
- Bulent Icgen
- Department of Environmental Engineering, Middle East Technical University, 06800, Ankara, Turkey.
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53
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Worthing KA, Coombs GW, Pang S, Abraham S, Saputra S, Trott DJ, Jordan D, Wong HS, Abraham RJ, Norris JM. Isolation of mecC MRSA in Australia. J Antimicrob Chemother 2016; 71:2348-9. [PMID: 27118772 DOI: 10.1093/jac/dkw138] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Kate A Worthing
- Faculty of Veterinary Science, McMaster Building B14, University of Sydney, NSW 2006, Australia
| | - Geoffrey W Coombs
- School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia PathWest Laboratory Medicine - WA, Fiona Stanley Hospital, Robin Warren Drive, Murdoch, WA 6150, Australia
| | - Stanley Pang
- School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia PathWest Laboratory Medicine - WA, Fiona Stanley Hospital, Robin Warren Drive, Murdoch, WA 6150, Australia
| | - Sam Abraham
- School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia
| | - Sugiyono Saputra
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Darren J Trott
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia
| | - David Jordan
- School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia New South Wales Department of Primary Industries, 1243 Bruxner Highway, Wollongbar, NSW 2477, Australia
| | - Hui San Wong
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Rebecca J Abraham
- School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA 6150, Australia PathWest Laboratory Medicine - WA, Fiona Stanley Hospital, Robin Warren Drive, Murdoch, WA 6150, Australia
| | - Jacqueline M Norris
- Faculty of Veterinary Science, McMaster Building B14, University of Sydney, NSW 2006, Australia
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Shapiro AB. Investigation of β-lactam antibacterial drugs, β-lactamases, and penicillin-binding proteins with fluorescence polarization and anisotropy: a review. Methods Appl Fluoresc 2016; 4:024002. [DOI: 10.1088/2050-6120/4/2/024002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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55
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Role of the Stringent Stress Response in the Antibiotic Resistance Phenotype of Methicillin-Resistant Staphylococcus aureus. Antimicrob Agents Chemother 2016; 60:2311-7. [PMID: 26833147 DOI: 10.1128/aac.02697-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/25/2016] [Indexed: 01/03/2023] Open
Abstract
Resistance to beta-lactam antibiotics in methicillin-resistantStaphylococcus aureus(MRSA) requires the presence of an acquired genetic determinant,mecAormecC, which encode penicillin-binding protein PBP2A or PBP2A', respectively. Although all MRSA strains share a mechanism of resistance, the phenotypic expression of beta-lactam resistance shows considerable strain-to-strain variation. The stringent stress response, a stress response that results from nutrient limitation, was shown to play a key role in determining the resistance level of an MRSA strain. In the present study, we validated the impact of the stringent stress response on transcription and translation ofmecAin the MRSA clinical isolate strain N315, which also carries known regulatory genes (mecI/mecR1/mecR2andblaI/blaR1) formecAtranscription. We showed that the impact of the stringent stress response on the resistance level may be restricted to beta-lactam resistance based on a "foreign" determinant such asmecA, as opposed to resistance based on mutations in the nativeS. aureusdeterminantpbpB(encoding PBP2). Our observations demonstrate that high-level resistance mediated by the stringent stress response follows the current model of beta-lactam resistance in which the native PBP2 protein is also essential for expression of the resistance phenotype. We also show that theStaphylococcus sciuri pbpDgene (also calledmecAI), the putative evolutionary precursor ofmecA, confers oxacillin resistance in anS. aureusstrain, generating a heterogeneous phenotype that can be converted to high and homogenous resistance by induction of the stringent stress response in the bacteria.
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56
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Brennan G, Herra C, Coleman D, O'Connell B, Shore A. Evaluation of commercial chromogenic media for the detection of meticillin-resistant Staphylococcus aureus. J Hosp Infect 2016; 92:287-92. [DOI: 10.1016/j.jhin.2015.10.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/27/2015] [Indexed: 11/30/2022]
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57
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[Methicillin-resistant Staphylococcus aureus carrying the mecC gene: an emerging problem?]. Enferm Infecc Microbiol Clin 2016; 34:277-9. [PMID: 26906690 DOI: 10.1016/j.eimc.2016.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 01/20/2016] [Indexed: 01/19/2023]
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58
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Xia J, Gao J, Tang W. Nosocomial infection and its molecular mechanisms of antibiotic resistance. Biosci Trends 2016; 10:14-21. [PMID: 26877142 DOI: 10.5582/bst.2016.01020] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nosocomial infection is a kind of infection, which is spread in various hospital environments, and leads to many serious diseases (e.g. pneumonia, urinary tract infection, gastroenteritis, and puerperal fever), and causes higher mortality than community-acquired infection. Bacteria are predominant among all the nosocomial infection-associated pathogens, thus a large number of antibiotics, such as aminoglycosides, penicillins, cephalosporins, and carbapenems, are adopted in clinical treatment. However, in recent years antibiotic resistance quickly spreads worldwide and causes a critical threat to public health. The predominant bacteria include Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii. In these bacteria, resistance emerged from antibiotic resistant genes and many of those can be exchanged between bacteria. With technical advances, molecular mechanisms of resistance have been gradually unveiled. In this review, recent advances in knowledge about mechanisms by which (i) bacteria hydrolyze antibiotics (e.g. extended spectrum β-lactamases, (ii) AmpC β-lactamases, carbapenemases), (iii) avoid antibiotic targeting (e.g. mutated vanA and mecA genes), (iv) prevent antibiotic permeation (e.g. porin deficiency), or (v) excrete intracellular antibiotics (e.g. active efflux pump) are summarized.
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Affiliation(s)
- Jufeng Xia
- Hepato-Biliary-Pancreatic Surgery Division, Department of Surgery, Graduate School of Medicine, The University of Tokyo
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59
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High Frequency of icaAD, clumping factors A/B, fib and eno Genes in Staphylococcus aureus Species Isolated From Wounds in Tehran, Iran during 2012-2013. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2015. [DOI: 10.5812/archcid.23033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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60
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Diaz R, Ramalheira E, Afreixo V, Gago B. Methicillin-resistant Staphylococcus aureus carrying the new mecC gene--a meta-analysis. Diagn Microbiol Infect Dis 2015; 84:135-40. [PMID: 26652130 DOI: 10.1016/j.diagmicrobio.2015.10.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/10/2015] [Accepted: 10/19/2015] [Indexed: 12/25/2022]
Abstract
In 2011, a new mecA gene homolog, named mecC gene, was found in isolates from both humans and animals. The discovery of methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene has caused speculations about the origin, epidemiology, and impact of these isolates. The objective of this work is to perform a meta-analysis on the prevalence of mecC MRSA, based on previously published results. Meta-analysis showed that the overall pooled prevalence is 0.009% (95% confidence interval=0.05-0.013) and that there was evidence of heterogeneity (P<0.01, I(2)=97%). In conclusion, the very low reported prevalence provides an important baseline to monitor the epidemiology of this emerging form of MRSA.
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Affiliation(s)
- Raquel Diaz
- Health Sciences Department, University of Aveiro, Institute for Research in Biomedicine-iBiMED, Health Sciences Program, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Elmano Ramalheira
- Health Sciences Department, University of Aveiro, Department of Medical Microbiology, Centro Hospitalar Baixo Vouga, Av. Artur Ravara, 3814-501, Aveiro, Portugal.
| | - Vera Afreixo
- Department of Mathematics, University of Aveiro, Institute for Biomedicine-iBiMED, Health Sciences Program, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Bruno Gago
- Health Sciences Department, University of Aveiro, Institute for Biomedicine-iBiMED, Health Sciences Program, University of Aveiro, 3810-193 Aveiro, Portugal.
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61
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Old Drugs To Treat Resistant Bugs: Methicillin-Resistant Staphylococcus aureus Isolates with mecC Are Susceptible to a Combination of Penicillin and Clavulanic Acid. Antimicrob Agents Chemother 2015; 59:7396-404. [PMID: 26392513 DOI: 10.1128/aac.01469-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/03/2015] [Indexed: 11/20/2022] Open
Abstract
β-Lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is mediated by the expression of an alternative penicillin-binding protein 2a (PBP2a) (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA, known as mecC, was identified in MRSA isolates from both humans and animals. In this study, we demonstrate that mecC-encoded PBP2c does not mediate resistance to penicillin. Rather, broad-spectrum β-lactam resistance in MRSA strains carrying mecC (mecC-MRSA strains) is mediated by a combination of both PBP2c and the distinct β-lactamase encoded by the blaZ gene of strain LGA251 (blaZLGA251), which is part of mecC-encoding staphylococcal cassette chromosome mec (SCCmec) type XI. We further demonstrate that mecC-MRSA strains are susceptible to the combination of penicillin and the β-lactam inhibitor clavulanic acid in vitro and that the same combination is effective in vivo for the treatment of experimental mecC-MRSA infection in wax moth larvae. Thus, we demonstrate how the distinct biological differences between mecA- and mecC-encoded PBP2a and PBP2c have the potential to be exploited as a novel approach for the treatment of mecC-MRSA infections.
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62
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Seyedmonir E, Yilmaz F, Icgen B. mecA Gene Dissemination Among Staphylococcal and Non-staphylococcal Isolates Shed in Surface Waters. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2015; 95:131-8. [PMID: 25733448 DOI: 10.1007/s00128-015-1510-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/25/2015] [Indexed: 05/03/2023]
Abstract
Aquatic ecosystems represent important vehicles for the dissemination of antibiotic resistant bacteria and antibiotic resistance genes. Of particular interest are methicillin-resistant staphylococci (MRS) harboring mecA gene that confers their resistance to β-lactams. Therefore, in this study, water samples collected from different locations of a river impacted by surrounding facilities and domestic effluents were analyzed to learn more about the occurrence of MRS and mecA gene. Out of 290, 12 surface water isolates displayed resistance to both cefoxitin and oxacillin antibiotics. Resistant staphylococcal and non-staphylococcal isolates, identified by 16S rRNA sequencing, were found to harbor mecA gene. The phylogenetic tree of partial mecA sequences obtained from staphylococcal and non-staphylococcal isolates showed sequence similarity values of 8 %-100 %. Surface water bodies receive contaminated waters via runoff, effluents from industrial, agricultural, and municipal discharges. Therefore, surface waters are not only hot spots for mecA harboring staphylococcal isolates but also non-staphylococcal isolates and require special scientific consideration.
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Affiliation(s)
- Elnaz Seyedmonir
- Department of Biochemistry, Middle East Technical University, 06800, Ankara, Turkey
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63
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Abstract
Staphylococcus aureus is a major human and veterinary pathogen worldwide. Methicillin-resistant S. aureus (MRSA) poses a significant and enduring problem to the treatment of infection by such strains. Resistance is usually conferred by the acquisition of a nonnative gene encoding a penicillin-binding protein (PBP2a), with significantly lower affinity for β-lactams. This resistance allows cell-wall biosynthesis, the target of β-lactams, to continue even in the presence of typically inhibitory concentrations of antibiotic. PBP2a is encoded by the mecA gene, which is carried on a distinct mobile genetic element (SCCmec), the expression of which is controlled through a proteolytic signal transduction pathway comprising a sensor protein (MecR1) and a repressor (MecI). Many of the molecular and biochemical mechanisms underlying methicillin resistance in S. aureus have been elucidated, including regulatory events and the structure of key proteins. Here we review recent advances in this area.
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Affiliation(s)
- Sharon J. Peacock
- Department of Medicine, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Gavin K. Paterson
- School of Biological, Biomedical, and Environmental Sciences, University of Hull, Hull HU6 7RX, United Kingdom
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64
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Fishovitz J, Taghizadeh N, Fisher JF, Chang M, Mobashery S. The Tipper-Strominger Hypothesis and Triggering of Allostery in Penicillin-Binding Protein 2a of Methicillin-Resistant Staphylococcus aureus (MRSA). J Am Chem Soc 2015; 137:6500-5. [PMID: 25964995 DOI: 10.1021/jacs.5b01374] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The transpeptidases involved in the synthesis of the bacterial cell wall (also known as penicillin-binding proteins, PBPs) have evolved to bind the acyl-D-Ala-D-Ala segment of the stem peptide of the nascent peptidoglycan for the physiologically important cross-linking of the cell wall. The Tipper-Strominger hypothesis stipulates that β-lactam antibiotics mimic the acyl-D-Ala-D-Ala moiety of the stem and, thus, are recognized by the PBPs with bactericidal consequences. We document that this mimicry exists also at the allosteric site of PBP2a of methicillin-resistant Staphylococcus aureus (MRSA). Interactions of different classes of β-lactam antibiotics, as mimics of the acyl-D-Ala-D-Ala moiety at the allosteric site, lead to a conformational change, across a distance of 60 Å to the active site. We directly visualize this change using an environmentally sensitive fluorescent probe affixed to the protein loops that frame the active site. This conformational mobility, documented in real time, allows antibiotic access to the active site of PBP2a. Furthermore, we document that this allosteric trigger enables synergy between two different β-lactam antibiotics, wherein occupancy at the allosteric site by one facilitates occupancy by a second at the transpeptidase catalytic site, thus lowering the minimal-inhibitory concentration. This synergy has important implications for the mitigation of facile emergence of resistance to these antibiotics by MRSA.
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Affiliation(s)
- Jennifer Fishovitz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Negin Taghizadeh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Mayland Chang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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65
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Strommenger B, Layer F, Klare I, Werner G. Pre-Use Susceptibility to Ceftaroline in Clinical Staphylococcus aureus Isolates from Germany: Is There a Non-Susceptible Pool to be Selected? PLoS One 2015; 10:e0125864. [PMID: 25955221 PMCID: PMC4425514 DOI: 10.1371/journal.pone.0125864] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/25/2015] [Indexed: 11/25/2022] Open
Abstract
Ceftaroline is a new cephalosporin active against Methicillin-resistant Staphylococcus aureus (MRSA). Based on a representative collection of clinical S. aureus isolates from Germany, supplemented with isolates of clonal lineages ST228 and ST239, we demonstrate the in-vitro susceptibility towards ceftaroline prior to its introduction into clinical use for a total of 219 isolates. Susceptibility testing was performed by broth microdilution, disc diffusion and Etest, respectively. Results were interpreted according to EUCAST guidelines and showed considerable variance in dependence on clonal affiliation of the isolates tested. Among isolates of widespread hospital-associated lineages we found a high proportion of clinical isolates with MICs close to the EUCAST breakpoint (MIC50/90 1.0/1.5 mg/L); currently, interpretation of these "borderline" MICs is complicated by a lack of concordant susceptibility testing methods and reasonable breakpoint determination. Isolates of clonal lineages ST228 and ST239 demonstrated increased MIC50/90 values of 2.5/3.33 mg/L. Sequencing of mecA revealed no association of resistance to a specific mecA polymorphism, but rather reveals two regions in the non-penicillin-binding domain of PbP2a which displayed different combinations of mutations putatively involved in resistance development. This study provides national baseline data to (i) adjust susceptibility testing methods and current breakpoints to clinical and epidemiological requirements, (ii) evaluate current breakpoints with respect to therapeutic outcome and (iii) monitor further resistance evolution.
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Affiliation(s)
- Birgit Strommenger
- National Reference Centre for Staphylococci and Enterococci, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - Franziska Layer
- National Reference Centre for Staphylococci and Enterococci, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - Ingo Klare
- National Reference Centre for Staphylococci and Enterococci, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
| | - Guido Werner
- National Reference Centre for Staphylococci and Enterococci, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany
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66
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Abdulgader SM, Shittu AO, Nicol MP, Kaba M. Molecular epidemiology of Methicillin-resistant Staphylococcus aureus in Africa: a systematic review. Front Microbiol 2015; 6:348. [PMID: 25983721 PMCID: PMC4415431 DOI: 10.3389/fmicb.2015.00348] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 04/08/2015] [Indexed: 11/13/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infections are a serious global problem, with considerable impact on patients and substantial health care costs. This systematic review provides an overview on the clonal diversity of MRSA, as well as the prevalence of Panton-Valentine leukocidin (PVL)-positive MRSA in Africa. A search on the molecular characterization of MRSA in Africa was conducted by two authors using predefined terms. We screened for articles published in English and French through to October 2014 from five electronic databases. A total of 57 eligible studies were identified. Thirty-four reports from 15 countries provided adequate genotyping data. CC5 is the predominant clonal complex in the healthcare setting in Africa. The hospital-associated MRSA ST239/ST241-III [3A] was identified in nine African countries. This clone was also described with SCCmec type IV [2B] in Algeria and Nigeria, and type V [5C] in Niger. In Africa, the European ST80-IV [2B] clone was limited to Algeria, Egypt and Tunisia. The clonal types ST22-IV [2B], ST36-II [2A], and ST612-IV [2B] were only reported in South Africa. No clear distinctions were observed between MRSA responsible for hospital and community infections. The community clones ST8-IV [2B] and ST88-IV [2B] were reported both in the hospital and community settings in Angola, Cameroon, Gabon, Ghana, Madagascar, Nigeria, and São Tomé and Príncipe. The proportion of PVL-positive MRSA carriage and/or infections ranged from 0.3 to 100% in humans. A number of pandemic clones were identified in Africa. Moreover, some MRSA clones are limited to specific countries or regions. We strongly advocate for more surveillance studies on MRSA in Africa.
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Affiliation(s)
- Shima M Abdulgader
- Division of Medical Microbiology, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Adebayo O Shittu
- Department of Microbiology, Obafemi Awolowo University Ile-Ife, Nigeria
| | - Mark P Nicol
- Division of Medical Microbiology, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa ; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa ; National Health Laboratory Service, Groote Schuur Hospital Cape Town, South Africa
| | - Mamadou Kaba
- Division of Medical Microbiology, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa ; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
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67
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Gómez P, Lozano C, González-Barrio D, Zarazaga M, Ruiz-Fons F, Torres C. High prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene in a semi-extensive red deer (Cervus elaphus hispanicus) farm in Southern Spain. Vet Microbiol 2015; 177:326-31. [PMID: 25912021 DOI: 10.1016/j.vetmic.2015.03.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 03/19/2015] [Accepted: 03/31/2015] [Indexed: 12/18/2022]
Abstract
The objective was to determine the prevalence of Staphylococcus aureus nasal carriage in red deer of a semi-extensive farm and in humans in contact with the estate animals, and to characterize obtained isolates. Nasal swabs of 65 deer and 15 humans were seeded on mannitol-salt-agar and oxacillin-resistance-screening-agar-base. Isolates were identified by microbiological and molecular methods. Antimicrobial susceptibility profile was determined for 16 antibiotics by disk-diffusion and the presence of eight antibiotic resistance genes, seven virulence genes and genes of immune-evasion-cluster (IEC) was analyzed by PCR. S. aureus was typed by PFGE-SmaI, spa, agr, SCCmec and MLST. Isolates were detected in 16 deer (24.6%). Eleven S. aureus isolates were methicillin-resistant (MRSA), and five were methicillin-susceptible (MSSA). All MRSA harbored mecC gene and were agr-III/SCCmecXI/ST1945 (four spa-t843 and seven spa-t1535). All mecC-MRSA carried blaZ-SCCmecXI and etd2, were IEC-type-E, and belonged to the same PFGE pattern. The five MSSA were typed as spa-t2420/agr-I/ST133. Regarding humans, S. aureus was recovered from six samples (40%). The isolates were MSSA and were typed as spa-t002/agr-II, spa-t012/agr-III or spa-t822/agr-III and showed different IEC types (A, B, D and F). blaZ and erm(A) genes were detected, as well as cna and tst genes. As conclusion, red deer analyzed in this study are frequent carriers of mecC-MRSA CC130 (16.9%), they are characterized by few resistance and virulence determinants, and by the presence of IEC type-E. Deer could be a source of mecC-MRSA which could potentially be transmitted to other animals, or even to humans.
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Affiliation(s)
- Paula Gómez
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
| | - Carmen Lozano
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
| | - David González-Barrio
- SaBio, Spanish Wildlife Research Institute IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - Myriam Zarazaga
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
| | - Francisco Ruiz-Fons
- SaBio, Spanish Wildlife Research Institute IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - Carmen Torres
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
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Cano García ME, Monteagudo Cimiano I, Mellado Encinas P, Ortega Álvarez C. Staphylococcus aureus resistente a meticilina portador del gen mecC en un paciente con infección de herida. Enferm Infecc Microbiol Clin 2015; 33:287-8. [DOI: 10.1016/j.eimc.2014.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/04/2014] [Accepted: 06/18/2014] [Indexed: 11/28/2022]
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Bessa LJ, Palmeira A, Gomes AS, Vasconcelos V, Sousa E, Pinto M, Martins da Costa P. Synergistic Effects Between Thioxanthones and Oxacillin Against Methicillin-Resistant Staphylococcus aureus. Microb Drug Resist 2015; 21:404-15. [PMID: 25789724 DOI: 10.1089/mdr.2014.0162] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The extensive use of antimicrobials is leaving medicine with few effective therapeutic options to treat many infections due to the fact that many organisms developed resistance to commonly used drugs. It is therefore pertinent to search not only for new antimicrobials but also for compounds able to restore or potentiate the activity of existing antibiotics. We have screened a library consisting of 40 (thio)xanthone derivatives for antibacterial activity and possible synergistic effects when used in combination with antibiotics. Nine out of the 40 compounds exhibited antibacterial activity against Gram-positive bacteria. Two xanthone derivatives, 1-formyl-4-hydroxy-3-methoxy (7), 2-formyl-3-hydroxy-4-methoxyxanthone (8) and the thioxanthone derivative 1-((2-(diethylamino)ethyl)amino)-4-propoxythioxanthone (10) and its hydrochloride form 13, showed activity against a methicillin-resistant Staphylococcus aureus (MRSA) isolate with minimum inhibitory concentration (MIC) values lower than 256 μg/ml. Thioxanthone 10 demonstrated antibacterial activity and also synergy when combined with ampicillin and oxacillin against MRSA. Additionally, thioxanthone 1-(piperidin-1-yl)-4-propoxythioxanthone (9), despite not having antibacterial activity presented remarkable synergy with oxacillin against MRSA; the MIC of tioxanthone 9 and oxacillin when both were in combination were 128 and 8 μg/ml, respectively. Thioxanthones 9 and 10 were also found to be synergistic when both were combined. Subsequently, docking simulations between thioxanthones 9 and 10 and the allosteric domain of penicillin-binding protein 2A (PBP2A) were undertaken in AutoDock Vina. Both compounds had the ability to bind with an allosteric domain of PBP2A, which may explain their synergy with oxacillin. These two thioxanthone derivatives with different profiles may be promising tools for restoring the activity of oxacillin against MRSA.
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Affiliation(s)
- Lucinda J Bessa
- 1 Laboratório de Microbiologia e Tecnologia Alimentar, Departamento de Produção Aquática, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto , Porto, Portugal .,2 Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto , Porto, Portugal
| | - Andreia Palmeira
- 3 Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Centro de Química Medicinal da Universidade do Porto (CEQUIMED-UP), Universidade do Porto , Porto, Portugal
| | - Ana S Gomes
- 3 Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Centro de Química Medicinal da Universidade do Porto (CEQUIMED-UP), Universidade do Porto , Porto, Portugal
| | - Vitor Vasconcelos
- 2 Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto , Porto, Portugal .,4 Departamento de Biologia, Faculdade de Ciências, Universidade do Porto , Porto, Portugal
| | - Emília Sousa
- 2 Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto , Porto, Portugal .,3 Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Centro de Química Medicinal da Universidade do Porto (CEQUIMED-UP), Universidade do Porto , Porto, Portugal
| | - Madalena Pinto
- 2 Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto , Porto, Portugal .,3 Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Centro de Química Medicinal da Universidade do Porto (CEQUIMED-UP), Universidade do Porto , Porto, Portugal
| | - Paulo Martins da Costa
- 1 Laboratório de Microbiologia e Tecnologia Alimentar, Departamento de Produção Aquática, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto , Porto, Portugal .,2 Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto , Porto, Portugal
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Espinosa-Gongora C, Harrison EM, Moodley A, Guardabassi L, Holmes MA. MRSA carrying mecC in captive mara. J Antimicrob Chemother 2015; 70:1622-4. [PMID: 25722301 PMCID: PMC4498296 DOI: 10.1093/jac/dkv024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/21/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To characterize the staphylococcal cassette chromosome mec (SCCmec), virulence and antimicrobial susceptibility of Staphylococcus aureus ST130 isolated from mara (Dolichotis patagonum), a large rodent species native to South America and kept in captivity at Copenhagen Zoo. METHODS The presence of mecC was confirmed by PCR in 15 S. aureus ST130 isolated from mara during a previous study. WGS was performed on two randomly selected isolates to characterize their genomes with respect to SCCmec, virulence and resistance gene content. Antimicrobial susceptibility was tested using commercial broth microdilution tests. RESULTS All the isolates belonged to spa type t528 ST130 and carried mecC. Based on WGS, mecC was 100% identical to the prototype sequence of S. aureus strain LGA251. The sequence of SCCmec type XI in the mara isolates had 23 SNPs compared with the one described in LGA251. The two sequenced strains harboured a set of virulence factors and other genomic features previously observed in ST130. Both strains carried norA as the only putative antimicrobial resistance gene in addition to mecC. CONCLUSIONS Our findings support the notion that a genetically conserved mecC-carrying MRSA ST130 clone is widespread in a variety of unrelated hosts in Denmark. Since the mara at Copenhagen Zoo have limited contact with humans and other animal species, it remains unclear whether mara are natural hosts of ST130 or acquired this lineage from unknown sources. The broad host range of MRSA ST130 supports its designation as a generalist lineage.
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Affiliation(s)
- C Espinosa-Gongora
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark
| | - E M Harrison
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - A Moodley
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark
| | - L Guardabassi
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark
| | - M A Holmes
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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Ghasemian A, Peerayeh SN, Bakhshi B, Mirzaee M. Detection of accessory gene regulator groups genes and cassette chromosome mec types among Staphylococcus aureus isolated from intensive care unit patients. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2015. [DOI: 10.1016/s2222-1808(14)60643-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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72
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In vivo effect of flucloxacillin in experimental endocarditis caused by mecC-positive staphylococcus aureus showing temperature-dependent susceptibility in vitro. Antimicrob Agents Chemother 2015; 59:2435-8. [PMID: 25605361 DOI: 10.1128/aac.04733-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene (mecC-MRSA) exhibited at 37°C MICs of oxacillin close to those of methicillin-susceptible S. aureus (MSSA). We investigated whether at this temperature, mecC-MRSA strains respond to flucloxacillin treatment like MSSA strains, using a rat model of endocarditis. Flucloxacillin (human-like kinetics of 2 g intravenously every 6 h) cured 80 to 100% of aortic vegetations infected with five different mecC-MRSA strains. These results suggest that mecC-MRSA infections may successfully respond to treatment with β-lactams.
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73
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Whole-genome sequence of Chryseobacterium oranimense, a colistin-resistant bacterium isolated from a cystic fibrosis patient in France. Antimicrob Agents Chemother 2015; 59:1696-706. [PMID: 25583710 DOI: 10.1128/aac.02417-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For the first time, we report the whole-genome sequence analysis of Chryseobacterium oranimense G311, a multidrug-resistant bacterium, from a cystic fibrosis patient in France, including resistance to colistin. Whole-genome sequencing of C. oranimense G311 was performed using Ion Torrent PGM, and RAST, the EMBL-EBI server, and the Antibiotic Resistance Gene-ANNOTation (ARG-ANNOT) database were used for annotation of all genes, including antibiotic resistance (AR) genes. General features of the C. oranimense G311 draft genome were compared to the other available genomes of Chryseobacterium gleum and Chryseobacterium sp. strain CF314. C. oranimense G311 was found to be resistant to all β-lactams, including imipenem, and to colistin. The genome size of C. oranimense G311 is 4,457,049 bp in length, with 37.70% GC content. We found 27 AR genes in the genome, including β-lactamase genes which showed little similarity to the known β-lactamase genes and could likely be novel. We found the type I polyketide synthase operon followed by a zeaxanthin glycosyltransferase gene in the genome, which could impart the yellow pigmentation of the isolate. We located the O-antigen biosynthesis cluster, and we also discovered a novel capsular polysaccharide biosynthesis cluster. We also found known mutations in the orthologs of the pmrA (E8D), pmrB (L208F and P360Q), and lpxA (G68D) genes. We speculate that the presence of the capsular cluster and mutations in these genes could explain the resistance of this bacterium to colistin. We demonstrate that whole-genome sequencing was successfully applied to decipher the resistome of a multidrug resistance bacterium associated with cystic fibrosis patients.
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Porrero MC, Valverde A, Fernández-Llario P, Díez-Guerrier A, Mateos A, Lavín S, Cantón R, Fernández-Garayzabal JF, Domínguez L. Staphylococcus aureus carrying mecC gene in animals and urban wastewater, Spain. Emerg Infect Dis 2014; 20:899-901. [PMID: 24751149 PMCID: PMC4012787 DOI: 10.3201/eid2005.130426] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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75
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Cavanagh JP, Hjerde E, Holden MTG, Kahlke T, Klingenberg C, Flægstad T, Parkhill J, Bentley SD, Sollid JUE. Whole-genome sequencing reveals clonal expansion of multiresistant Staphylococcus haemolyticus in European hospitals. J Antimicrob Chemother 2014; 69:2920-7. [PMID: 25038069 PMCID: PMC4195474 DOI: 10.1093/jac/dku271] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/16/2014] [Accepted: 06/20/2014] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Staphylococcus haemolyticus is an emerging cause of nosocomial infections, primarily affecting immunocompromised patients. A comparative genomic analysis was performed on clinical S. haemolyticus isolates to investigate their genetic relationship and explore the coding sequences with respect to antimicrobial resistance determinants and putative hospital adaptation. METHODS Whole-genome sequencing was performed on 134 isolates of S. haemolyticus from geographically diverse origins (Belgium, 2; Germany, 10; Japan, 13; Norway, 54; Spain, 2; Switzerland, 43; UK, 9; USA, 1). Each genome was individually assembled. Protein coding sequences (CDSs) were predicted and homologous genes were categorized into three types: Type I, core genes, homologues present in all strains; Type II, unique core genes, homologues shared by only a subgroup of strains; and Type III, unique genes, strain-specific CDSs. The phylogenetic relationship between the isolates was built from variable sites in the form of single nucleotide polymorphisms (SNPs) in the core genome and used to construct a maximum likelihood phylogeny. RESULTS SNPs in the genome core regions divided the isolates into one major group of 126 isolates and one minor group of isolates with highly diverse genomes. The major group was further subdivided into seven clades (A-G), of which four (A-D) encompassed isolates only from Europe. Antimicrobial multiresistance was observed in 77.7% of the collection. High levels of homologous recombination were detected in genes involved in adherence, staphylococcal host adaptation and bacterial cell communication. CONCLUSIONS The presence of several successful and highly resistant clones underlines the adaptive potential of this opportunistic pathogen.
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Affiliation(s)
- Jorunn Pauline Cavanagh
- Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Erik Hjerde
- Department of Chemistry, Norstruct, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Tim Kahlke
- Department of Chemistry, Norstruct, UiT The Arctic University of Norway, Tromsø, Norway
| | - Claus Klingenberg
- Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Trond Flægstad
- Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Stephen D Bentley
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK Department of Medicine, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 0SP, UK
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Methicillin resistance in Staphylococcus isolates: The “mec alphabet” with specific consideration of mecC, a mec homolog associated with zoonotic S. aureus lineages. Int J Med Microbiol 2014; 304:794-804. [DOI: 10.1016/j.ijmm.2014.06.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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The mecA homolog mecC confers resistance against β-lactams in Staphylococcus aureus irrespective of the genetic strain background. Antimicrob Agents Chemother 2014; 58:3791-8. [PMID: 24752255 DOI: 10.1128/aac.02731-13] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In staphylococci, methicillin resistance is mediated by mecA-encoded penicillin-binding protein 2a (PBP2a), which has a low affinity for beta-lactams. Recently, a novel PBP2a homolog was described as being encoded by mecC, which shares only 70% similarity to mecA. To prove that mecC is the genetic determinant that confers methicillin resistance in Staphylococcus aureus, a mecC knockout strain was generated. The S. aureus ΔmecC strain showed considerably reduced oxacillin and cefoxitin MICs (0.25 and 4 μg/ml, respectively) compared to those of the corresponding wild-type methicillin-resistant S. aureus (MRSA) strain (8 and 16 μg/ml, respectively). Complementing the mutant in trans with wild-type mecC restored the resistance to oxacillin and cefoxitin. By expressing mecC and mecA in different S. aureus clonal lineages, we found that mecC mediates resistance irrespective of the genetic strain background, yielding oxacillin and cefoxitin MIC values comparable to those with mecA. In addition, we showed that mecC expression is inducible by oxacillin, which supports the assumption that a functional beta-lactam-dependent regulatory system is active in MRSA strains possessing staphylococcal cassette chromosome mec (SCCmec) type XI. In summary, we showed that mecC is inducible by oxacillin and mediates beta-lactam resistance in SCCmec type XI-carrying strains as well as in different S. aureus genetic backgrounds. Furthermore, our results could explain the comparatively low MICs for clinical mecC-harboring S. aureus isolates.
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Accessory Gene Regulator Specificity Groups Among Staphylococcus aureus Isolated From Hospitalized Children. ARCHIVES OF PEDIATRIC INFECTIOUS DISEASES 2014. [DOI: 10.5812/pedinfect.16096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Dordel J, Kim C, Chung M, Pardos de la Gándara M, Holden MTJ, Parkhill J, de Lencastre H, Bentley SD, Tomasz A. Novel determinants of antibiotic resistance: identification of mutated loci in highly methicillin-resistant subpopulations of methicillin-resistant Staphylococcus aureus. mBio 2014; 5:e01000. [PMID: 24713324 PMCID: PMC3993859 DOI: 10.1128/mbio.01000-13] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/10/2014] [Indexed: 12/30/2022] Open
Abstract
We identified mutated genes in highly resistant subpopulations of methicillin-resistant Staphylococcus aureus (MRSA) that are most likely responsible for the historic failure of the β-lactam family of antibiotics as therapeutic agents against these important pathogens. Such subpopulations are produced during growth of most clinical MRSA strains, including the four historically early MRSA isolates studied here. Chromosomal DNA was prepared from the highly resistant cells along with DNA from the majority of cells (poorly resistant cells) followed by full genome sequencing. In the highly resistant cells, mutations were identified in 3 intergenic sequences and 27 genes representing a wide range of functional categories. A common feature of these mutations appears to be their capacity to induce high-level β-lactam resistance and increased amounts of the resistance protein PBP2A in the bacteria. The observations fit a recently described model in which the ultimate controlling factor of the phenotypic expression of β-lactam resistance in MRSA is a RelA-mediated stringent response. IMPORTANCE It has been well established that the level of antibiotic resistance (i.e., minimum concentration of a β-lactam antibiotic needed to inhibit growth) of a methicillin-resistant Staphylococcus aureus (MRSA) strain depends on the transcription and translation of the resistance protein PBP2A. Here we describe mutated loci in an additional novel set of genetic determinants that appear to be essential for the unusually high resistance levels typical of subpopulations of staphylococci that are produced with unique low frequency in most MRSA clinical isolates. We propose that mutations in these determinants can trigger induction of the stringent stress response which was recently shown to cause increased transcription/translation of the resistance protein PBP2A in parallel with the increased level of resistance.
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Affiliation(s)
- Janina Dordel
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Choonkeun Kim
- Laboratory of Microbiology, The Rockefeller University, New York, New York, USA
| | - Marilyn Chung
- Laboratory of Microbiology, The Rockefeller University, New York, New York, USA
| | | | - Matthew T. J. Holden
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | | | | | - Alexander Tomasz
- Laboratory of Microbiology, The Rockefeller University, New York, New York, USA
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Gómez P, González-Barrio D, Benito D, García JT, Viñuela J, Zarazaga M, Ruiz-Fons F, Torres C. Detection of methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene in wild small mammals in Spain. J Antimicrob Chemother 2014; 69:2061-4. [PMID: 24710026 DOI: 10.1093/jac/dku100] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES To determine the rate of Staphylococcus aureus faecal carriage in 101 wild small mammals in Spain and to characterize the isolates obtained. METHODS Faecal samples were seeded on mannitol salt agar and ORSAB plates. The presence of the resistance genes mecA, mecC and blaZ and the new blaZ allotype associated with staphylococcal cassette chromosome mec (SCCmec) XI (blaZ-SCCmecXI) was studied by PCR. S. aureus isolates were characterized by spa typing, agr typing and multilocus sequence typing. The presence of immune evasion cluster (IEC) genes and virulence genes was analysed by PCR. RESULTS S. aureus was detected in 13/101 studied faecal samples and one isolate per positive sample was further studied. Two S. aureus isolates were methicillin-resistant S. aureus (MRSA) (recovered from wood mice, Apodemus sylvaticus) and 11 were methicillin-susceptible S. aureus (MSSA). Both MRSA isolates harboured the mecC gene and the novel blaZ-SCCmecXI, were typed as spa-t1535/agrIII/ST1945(CC130)/SCCmecXI (where ST stands for sequence type and CC stands for clonal complex), carried the exfoliative toxin etd2 gene and were IEC type E. Eight different spa types were identified among the 11 MSSA isolates (five new) and six different sequence types were identified (two new). All MSSA strains were susceptible to the antibiotics tested except one blaZ-positive penicillin-resistant isolate (spa-t120/agrII/ST15). MSSA isolates were ascribed to the CCs (number of strains) CC5 (1), CC1956 (4) and singleton (6). Nine of 11 MSSA isolates carried the cna virulence gene. Only one MSSA isolate carried IEC genes (type C). CONCLUSIONS This is the first report of MRSA carrying mecC in faecal samples of wild small mammals in Spain. These resistant isolates carried genes of the IEC system, unusual in S. aureus from animals. Wild small mammals could be a reservoir of the mecC gene with important implications for public health.
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Affiliation(s)
- Paula Gómez
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
| | | | - Daniel Benito
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
| | - Jesús T García
- Ecology group, IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - Javier Viñuela
- Ecology group, IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain
| | - Myriam Zarazaga
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
| | | | - Carmen Torres
- Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain
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Schlotter K, Huber-Schlenstedt R, Gangl A, Hotzel H, Monecke S, Müller E, Reißig A, Proft S, Ehricht R. Multiple cases of methicillin-resistant CC130 Staphylococcus aureus harboring mecC in milk and swab samples from a Bavarian dairy herd. J Dairy Sci 2014; 97:2782-8. [PMID: 24630668 DOI: 10.3168/jds.2013-7378] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 02/04/2014] [Indexed: 11/19/2022]
Abstract
The discovery of a new mecA homolog, mecC, necessitates a modification of diagnostic procedures for the identification of methicillin-resistant Staphylococcus aureus (MRSA), as most assays used for the genotypic and phenotypic mecA detection cannot currently recognize mecC. Although the prevalence, distribution, and importance of mecC are not yet completely understood, an exchange of mecC-MRSA between humans and animals seems possible. All previously reported observations of mecC-positive strains have been sporadic. To the best of our knowledge, this is the first report about multiple cases of mecC-positive Staph. aureus in 1 dairy herd. Clonal complex 130 Staph. aureus harboring mecC were found in milk samples from 16 of 56 lactating cows kept in a herd in Bavaria, Germany. Almost all quarter milk samples positive for mecC-MRSA had the lowest possible California Mastitis Test score; composite somatic cell counts obtained from monthly milk recordings showed a mean of 51,600 cells/mL in mecC-MRSA affected cows. Additionally, mecC-positive clonal complex 130 Staph. aureus were detected in swab samples from the mammary skin and a teat lesion of 1 cow from this herd. This report suggests that mecC-carrying strains are able to spread among livestock, and that they have the ability to cause multiple cases in single herds. Therefore, future studies targeting MRSA in dairy cows need to consider mecC.
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Affiliation(s)
- K Schlotter
- Tiergesundheitsdienst Bayern e.V. (Bavarian Animal Health Service), Senator-Gerauer-Straße 23, 85586 Poing, Germany.
| | - R Huber-Schlenstedt
- Tiergesundheitsdienst Bayern e.V. (Bavarian Animal Health Service), Senator-Gerauer-Straße 23, 85586 Poing, Germany
| | - A Gangl
- Tiergesundheitsdienst Bayern e.V. (Bavarian Animal Health Service), Senator-Gerauer-Straße 23, 85586 Poing, Germany
| | - H Hotzel
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Naumburger Str. 96a, 07743 Jena, Germany
| | - S Monecke
- Institute for Medical Microbiology and Hygiene, Technical University of Dresden, Fiedlerstr. 42, 01307 Dresden, Germany; Alere Technologies GmbH, Loebstedter Str. 103-105, 07749 Jena, Germany
| | - E Müller
- Alere Technologies GmbH, Loebstedter Str. 103-105, 07749 Jena, Germany
| | - A Reißig
- Alere Technologies GmbH, Loebstedter Str. 103-105, 07749 Jena, Germany
| | - S Proft
- Alere Technologies GmbH, Loebstedter Str. 103-105, 07749 Jena, Germany
| | - R Ehricht
- Alere Technologies GmbH, Loebstedter Str. 103-105, 07749 Jena, Germany
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Extensive genetic diversity identified among sporadic methicillin-resistant Staphylococcus aureus isolates recovered in Irish hospitals between 2000 and 2012. Antimicrob Agents Chemother 2014; 58:1907-17. [PMID: 24395241 DOI: 10.1128/aac.02653-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Clonal replacement of predominant nosocomial methicillin-resistant Staphylococcus aureus (MRSA) strains has occurred several times in Ireland during the last 4 decades. However, little is known about sporadically occurring MRSA in Irish hospitals or in other countries. Eighty-eight representative pvl-negative sporadic MRSA isolates recovered in Irish hospitals between 2000 and 2012 were investigated. These yielded unusual pulsed-field gel electrophoresis and antibiogram-resistogram typing patterns distinct from those of the predominant nosocomial MRSA clone, ST22-MRSA-IV, during the study period. Isolates were characterized by spa typing and DNA microarray profiling for multilocus sequence type (MLST) clonal complex (CC) and/or sequence type (ST) and SCCmec type assignment, as well as for detection of virulence and antimicrobial resistance genes. Conventional PCR-based SCCmec subtyping was undertaken when necessary. Extensive diversity was detected, including 38 spa types, 13 MLST-CCs (including 18 STs among 62 isolates assigned to STs), and 25 SCCmec types (including 2 possible novel SCCmec elements and 7 possible novel SCCmec subtypes). Fifty-four MLST-spa-SCCmec type combinations were identified. Overall, 68.5% of isolates were assigned to nosocomial lineages, with ST8-t190-MRSA-IID/IIE±SCCM1 predominating (17.4%), followed by CC779/ST779-t878-MRSA-ψSCCmec-SCC-SCCCRISPR (7.6%) and CC22/ST22-t032-MRSA-IVh (5.4%). Community-associated clones, including CC1-t127/t386/t2279-MRSA-IV, CC59-t216-MRSA-V, CC8-t008-MRSA-IVa, and CC5-t002/t242-MRSA-IV/V, and putative animal-associated clones, including CC130-t12399-MRSA-XI, ST8-t064-MRSA-IVa, ST398-t011-MRSA-IVa, and CC6-t701-MRSA-V, were also identified. In total, 53.3% and 47.8% of isolates harbored genes for resistance to two or more classes of antimicrobial agents and two or more mobile genetic element-encoded virulence-associated factors, respectively. Effective ongoing surveillance of sporadic nosocomial MRSA is warranted for early detection of emerging clones and reservoirs of virulence, resistance, and SCCmec genes.
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Kim C, Mwangi M, Chung M, Milheirço C, de Lencastre H, Tomasz A. The mechanism of heterogeneous beta-lactam resistance in MRSA: key role of the stringent stress response. PLoS One 2013; 8:e82814. [PMID: 24349368 PMCID: PMC3857269 DOI: 10.1371/journal.pone.0082814] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 10/28/2013] [Indexed: 11/30/2022] Open
Abstract
All methicillin resistant S. aureus (MRSA) strains carry an acquired genetic determinant – mecA or mecC - which encode for a low affinity penicillin binding protein –PBP2A or PBP2A′ – that can continue the catalysis of peptidoglycan transpeptidation in the presence of high concentrations of beta-lactam antibiotics which would inhibit the native PBPs normally involved with the synthesis of staphylococcal cell wall peptidoglycan. In contrast to this common genetic and biochemical mechanism carried by all MRSA strains, the level of beta-lactam antibiotic resistance shows a very wide strain to strain variation, the mechanism of which has remained poorly understood. The overwhelming majority of MRSA strains produce a unique – heterogeneous – phenotype in which the great majority of the bacteria exhibit very poor resistance often close to the MIC value of susceptible S. aureus strains. However, cultures of such heterogeneously resistant MRSA strains also contain subpopulations of bacteria with extremely high beta-lactam MIC values and the resistance level and frequency of the highly resistant cells in such strain is a characteristic of the particular MRSA clone. In the study described in this communication, we used a variety of experimental models to understand the mechanism of heterogeneous beta-lactam resistance. Methicillin-susceptible S. aureus (MSSA) that received the mecA determinant in the laboratory either on a plasmid or in the form of a chromosomal SCCmec cassette, generated heterogeneously resistant cultures and the highly resistant subpopulations that emerged in these models had increased levels of PBP2A and were composed of bacteria in which the stringent stress response was induced. Each of the major heterogeneously resistant clones of MRSA clinical isolates could be converted to express high level and homogeneous resistance if the growth medium contained an inducer of the stringent stress response.
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Affiliation(s)
- Choonkeun Kim
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
| | - Michael Mwangi
- Department of Veterinary and Biomedical Sciences, Penn State University, University Park, Pennsylvania, United States of America
| | - Marilyn Chung
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
| | - Catarina Milheirço
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Herminia de Lencastre
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Alexander Tomasz
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
- * E-mail:
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84
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Paterson GK, Harrison EM, Holmes MA. The emergence of mecC methicillin-resistant Staphylococcus aureus. Trends Microbiol 2013; 22:42-7. [PMID: 24331435 PMCID: PMC3989053 DOI: 10.1016/j.tim.2013.11.003] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/12/2013] [Accepted: 11/12/2013] [Indexed: 12/31/2022]
Abstract
A novel mecA homologue, mecC, confers methicillin resistance to methicillin-resistant Staphylococcus aureus (MRSA). mecC MRSA produce negative results with common diagnostic tools. Reported from throughout Western Europe. Recent increase in Denmark. Found in a range of host species and may pose a zoonotic risk to humans.
The report of methicillin-resistant Staphylococcus aureus (MRSA) encoding a divergent mecA gene in 2011 was highly significant. This homologue, designated mecC, poses diagnostic problems with the potential to be misdiagnosed as methicillin-sensitive S. aureus, with important potential consequences for individual patients and for the surveillance of MRSA. mecC MRSA have now been reported from 13 European countries and have been isolated from 14 different host species, with evidence of a recent increase in Denmark. The emergence of mecC MRSA is a topic of interest to human and veterinary microbiology, and we consider it timely to review here its discovery and subsequent investigation.
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Affiliation(s)
- Gavin K Paterson
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK.
| | - Ewan M Harrison
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Mark A Holmes
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
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85
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Harrison EM, Paterson GK, Holden MTG, Ba X, Rolo J, Morgan FJE, Pichon B, Kearns A, Zadoks RN, Peacock SJ, Parkhill J, Holmes MA. A novel hybrid SCCmec-mecC region in Staphylococcus sciuri. J Antimicrob Chemother 2013; 69:911-8. [PMID: 24302651 PMCID: PMC3956370 DOI: 10.1093/jac/dkt452] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Methicillin resistance in Staphylococcus spp. results from the expression of an alternative penicillin-binding protein 2a (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA known as mecC (formerly mecALGA251) was identified in Staphylococcus aureus isolates from both humans and animals. In this study, we identified two Staphylococcus sciuri subsp. carnaticus isolates from bovine infections that harbour three different mecA homologues: mecA, mecA1 and mecC. METHODS We subjected the two isolates to whole-genome sequencing to further understand the genetic context of the mec-containing region. We also used PCR and RT-PCR to investigate the excision and expression of the SCCmec element and mec genes, respectively. RESULTS Whole-genome sequencing revealed a novel hybrid SCCmec region at the orfX locus consisting of a class E mec complex (mecI-mecR1-mecC1-blaZ) located immediately downstream of a staphylococcal cassette chromosome mec (SCCmec) type VII element. A second SCCmec attL site (attL2), which was imperfect, was present downstream of the mecC region. PCR analysis of stationary-phase cultures showed that both the SCCmec type VII element and a hybrid SCCmec-mecC element were capable of excision from the genome and forming a circular intermediate. Transcriptional analysis showed that mecC and mecA, but not mecA1, were both expressed in liquid culture supplemented with oxacillin. CONCLUSIONS Overall, this study further highlights that a range of staphylococcal species harbour the mecC gene and furthers the view that coagulase-negative staphylococci associated with animals may act as reservoirs of antibiotic resistance genes for more pathogenic staphylococcal species.
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Affiliation(s)
- Ewan M Harrison
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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86
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Paterson GK, Morgan FJE, Harrison EM, Cartwright EJP, Török ME, Zadoks RN, Parkhill J, Peacock SJ, Holmes MA. Prevalence and characterization of human mecC methicillin-resistant Staphylococcus aureus isolates in England. J Antimicrob Chemother 2013; 69:907-10. [PMID: 24284779 PMCID: PMC3956372 DOI: 10.1093/jac/dkt462] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Objectives There are limited data available on the epidemiology and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the human population that encode the recently described mecA homologue, mecC. To address this knowledge gap we undertook a prospective prevalence study in England to determine the prevalence of mecC among MRSA isolates. Patients and methods Three hundred and thirty-five sequential MRSA isolates from individual patients were collected from each of six clinical microbiology laboratories in England during 2011–12. These were tested by PCR or genome sequencing to differentiate those encoding mecA and mecC. mecC-positive isolates were further characterized by multilocus sequence typing, spa typing, antimicrobial susceptibility profile and detection of PBP2a using commercially available kits. Results Nine out of the 2010 MRSA isolates tested were mecC positive, indicating a prevalence among MRSA in England of 0.45% (95% CI 0.24%–0.85%). The remainder were mecA positive. Eight out of these nine mecC MRSA isolates belonged to clonal complex 130, the other being sequence type 425. Resistance to non-β-lactam antibiotics was rare among these mecC MRSA isolates and all were phenotypically identified as MRSA using oxacillin and cefoxitin according to BSAC disc diffusion methodology. However, all nine mecC isolates gave a negative result using three different commercial PBP2a detection assays. Conclusions mecC MRSA are currently rare among MRSA isolated from humans in England and this study provides an important baseline prevalence rate to monitor future changes, which may be important given the increasing prevalence of mecC MRSA reported in Denmark.
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Affiliation(s)
- G K Paterson
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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87
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The dynamics of peptidoglycan structure and function: conference report on the 3rd Great Wall Symposium. Res Microbiol 2013; 165:60-7. [PMID: 24239960 DOI: 10.1016/j.resmic.2013.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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88
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Affiliation(s)
- Alexander Tomasz
- Laboratory of Microbiology and Infectious Diseases, The Rockefeller University, New York, NY, USA.
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89
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Otero LH, Rojas-Altuve A, Llarrull LI, Carrasco-López C, Kumarasiri M, Lastochkin E, Fishovitz J, Dawley M, Hesek D, Lee M, Johnson JW, Fisher JF, Chang M, Mobashery S, Hermoso JA. How allosteric control of Staphylococcus aureus penicillin binding protein 2a enables methicillin resistance and physiological function. Proc Natl Acad Sci U S A 2013; 110:16808-13. [PMID: 24085846 PMCID: PMC3800995 DOI: 10.1073/pnas.1300118110] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expression of penicillin binding protein 2a (PBP2a) is the basis for the broad clinical resistance to the β-lactam antibiotics by methicillin-resistant Staphylococcus aureus (MRSA). The high-molecular mass penicillin binding proteins of bacteria catalyze in separate domains the transglycosylase and transpeptidase activities required for the biosynthesis of the peptidoglycan polymer that comprises the bacterial cell wall. In bacteria susceptible to β-lactam antibiotics, the transpeptidase activity of their penicillin binding proteins (PBPs) is lost as a result of irreversible acylation of an active site serine by the β-lactam antibiotics. In contrast, the PBP2a of MRSA is resistant to β-lactam acylation and successfully catalyzes the DD-transpeptidation reaction necessary to complete the cell wall. The inability to contain MRSA infection with β-lactam antibiotics is a continuing public health concern. We report herein the identification of an allosteric binding domain--a remarkable 60 Å distant from the DD-transpeptidase active site--discovered by crystallographic analysis of a soluble construct of PBP2a. When this allosteric site is occupied, a multiresidue conformational change culminates in the opening of the active site to permit substrate entry. This same crystallographic analysis also reveals the identity of three allosteric ligands: muramic acid (a saccharide component of the peptidoglycan), the cell wall peptidoglycan, and ceftaroline, a recently approved anti-MRSA β-lactam antibiotic. The ability of an anti-MRSA β-lactam antibiotic to stimulate allosteric opening of the active site, thus predisposing PBP2a to inactivation by a second β-lactam molecule, opens an unprecedented realm for β-lactam antibiotic structure-based design.
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Affiliation(s)
- Lisandro H. Otero
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
| | - Alzoray Rojas-Altuve
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
| | - Leticia I. Llarrull
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Cesar Carrasco-López
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
| | - Malika Kumarasiri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Elena Lastochkin
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Jennifer Fishovitz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Matthew Dawley
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Dusan Hesek
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Jarrod W. Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Jed F. Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Mayland Chang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Juan A. Hermoso
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
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90
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Shore AC, Coleman DC. Staphylococcal cassette chromosome mec: Recent advances and new insights. Int J Med Microbiol 2013; 303:350-9. [DOI: 10.1016/j.ijmm.2013.02.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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91
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Identification of Functional Regulatory Residues of the β -Lactam Inducible Penicillin Binding Protein in Methicillin-Resistant Staphylococcus aureus. CHEMOTHERAPY RESEARCH AND PRACTICE 2013; 2013:614670. [PMID: 23984067 PMCID: PMC3745919 DOI: 10.1155/2013/614670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 06/19/2013] [Accepted: 07/03/2013] [Indexed: 11/30/2022]
Abstract
Resistance to methicillin by Staphylococcus aureus is a persistent clinical problem worldwide. A mechanism for resistance has been proposed in which methicillin resistant Staphylococcus aureus (MRSA) isolates acquired a new protein called β-lactam inducible penicillin binding protein (PBP-2′). The PBP-2′ functions by substituting other penicillin binding proteins which have been inhibited by β-lactam antibiotics. Presently, there is no structural and regulatory information on PBP-2′ protein. We conducted a complete structural and functional regulatory analysis of PBP-2′ protein. Our analysis revealed that the PBP-2′ is very stable with more hydrophilic amino acids expressing antigenic sites. PBP-2′ has three striking regulatory points constituted by first penicillin binding site at Ser25, second penicillin binding site at Ser405, and finally a single metallic ligand binding site at Glu657 which binds to Zn2+ ions. This report highlights structural features of PBP-2′ that can serve as targets for developing new chemotherapeutic agents and conducting site direct mutagenesis experiments.
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92
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Use of Vitek 2 antimicrobial susceptibility profile to identify mecC in methicillin-resistant Staphylococcus aureus. J Clin Microbiol 2013; 51:2732-4. [PMID: 23720794 PMCID: PMC3719650 DOI: 10.1128/jcm.00847-13] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The emergence of mecC methicillin-resistant Staphylococcus aureus (MRSA) poses a diagnostic challenge for clinical microbiology laboratories. Using the Vitek 2 system, we tested a panel of 896 Staphylococcus aureus isolates and found that an oxacillin-sensitive/cefoxitin-resistant profile had a sensitivity of 88.7% and a specificity of 99.5% for the identification of mecC MRSA isolates. The presence of the mecC gene, determined by bacterial whole-genome sequencing, was used as the gold standard. This profile could provide a zero-cost screening method for identification of mecC-positive MRSA strains.
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93
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Mwangi MM, Kim C, Chung M, Tsai J, Vijayadamodar G, Benitez M, Jarvie TP, Du L, Tomasz A. Whole-genome sequencing reveals a link between β-lactam resistance and synthetases of the alarmone (p)ppGpp in Staphylococcus aureus. Microb Drug Resist 2013; 19:153-9. [PMID: 23659600 DOI: 10.1089/mdr.2013.0053] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The overwhelming majority of methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates exhibit a peculiar heterogeneous resistance to β-lactam antibiotics: in cultures of such strains, the majority of cells display only a low level of methicillin resistance--often close to the MIC breakpoint of susceptible strains. Yet, in the same cultures, subpopulations of bacteria exhibiting very high levels of resistance are also present with variable frequencies, which are characteristic of the particular MRSA lineage. The mechanism of heterogeneous resistance is not understood. We describe here an experimental system for exploring the mechanism of heterogeneous resistance. Copies of the resistance gene mecA cloned into a temperature-sensitive plasmid were introduced into the fully sequenced methicillin-susceptible clinical isolate S. aureus strain 476. Transductants of strain 476 expressed methicillin resistance in a heterogeneous fashion: the great majority of cells showed only low MIC (0.75 μg/ml) for the antibiotic, but a minority population of highly resistant bacteria (MIC >300 μg/ml) was also present with a frequency of ∼10(-4). The genetic backgrounds of the majority and minority cells were compared by whole-genome sequencing: the only differences detectable were two point mutations in relA of the highly resistant minority population of bacteria. The relA gene codes for the synthesis of (p)ppGpp, an effector of the stringent stress response. Titration of (p)ppGpp showed increased amounts of this effector in the highly resistant cells. Involvement of (p)ppGpp synthesis genes may explain some of the perplexing aspects of β-lactam resistance in MRSA, since many environmental and genetic changes can modulate cellular levels of (p)ppGpp.
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Affiliation(s)
- Michael M Mwangi
- Laboratory of Microbiology, The Rockefeller University, New York, NY 10065, USA
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94
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Harrison EM, Paterson GK, Holden MTG, Larsen J, Stegger M, Larsen AR, Petersen A, Skov RL, Christensen JM, Bak Zeuthen A, Heltberg O, Harris SR, Zadoks RN, Parkhill J, Peacock SJ, Holmes MA. Whole genome sequencing identifies zoonotic transmission of MRSA isolates with the novel mecA homologue mecC. EMBO Mol Med 2013; 5:509-15. [PMID: 23526809 PMCID: PMC3628104 DOI: 10.1002/emmm.201202413] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/06/2013] [Accepted: 02/08/2013] [Indexed: 12/16/2022] Open
Abstract
Several methicillin-resistant Staphylococcus aureus (MRSA) lineages that carry a novel mecA homologue (mecC) have recently been described in livestock and humans. In Denmark, two independent human cases of mecC-MRSA infection have been linked to a livestock reservoir. We investigated the molecular epidemiology of the associated MRSA isolates using whole genome sequencing (WGS). Single nucleotide polymorphisms (SNP) were defined and compared to a reference genome to place the isolates into a phylogenetic context. Phylogenetic analysis revealed two distinct farm-specific clusters comprising isolates from the human case and their own livestock, whereas human and animal isolates from the same farm only differed by a small number of SNPs, which supports the likelihood of zoonotic transmission. Further analyses identified a number of genes and mutations that may be associated with host interaction and virulence. This study demonstrates that mecC-MRSA ST130 isolates are capable of transmission between animals and humans, and underscores the potential of WGS in epidemiological investigations and source tracking of bacterial infections.
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Affiliation(s)
- Ewan M Harrison
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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