Comparative Molecular Analysis of Community- or Hospital-Acquired Methicillin-Resistant
            <i>Staphylococcus aureus</i>

Fey, Paul D.; Saïd-Salim, Battouli; Rupp, Mark E.; Hinrichs, Steven H.; Boxrud, David; Davis, Catherine; Kreiswirth, Barry N.; Schlievert, Patrick M.

doi:10.1128/aac.47.1.196-203.2003

Cited by 315 publications

(255 citation statements)

References 32 publications

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“…The genetically diverse community-acquired MRSA (CA-MRSA) were reported to harbor preferentially SCCmec type IV (9,16,26). The sporadic MRSA isolates included in our study also had very diverse genetic backgrounds, and they carried most frequently either SCCmec type III (10 isolates) or IV (13 isolates).…”

Section: Discussionmentioning

confidence: 95%

Evolution of Sporadic Isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) in Hospitals and Their Similarities to Isolates of Community-Acquired MRSA

2003

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Forty-one methicillin-resistant Staphylococcus aureus (MRSA) hospital isolates that clearly differed from the six major pandemic clones of MRSA in pulsed-field gel electrophoresis type, mecA and Tn554 polymorphism, and epidemic behavior were selected from an international strain collection for more detailed characterization. SpaA typing, multilocus sequence typing, and SCCmec (staphylococcal cassette chromosome mec) typing demonstrated extensive diversity among these sporadic isolates both in genetic background and also in the structure of the associated SCCmec elements. Nevertheless, the isolates could be grouped into restricted clonal complexes by using the BURST (i.e., based upon related sequence types) program algorithm, which predicted that most sporadic MRSA isolates evolved from pandemic MRSA clones. Several of the sporadic MRSA resembled community-acquired MRSA isolates in properties that included a relatively limited multiresistance pattern, faster growth rates, diversity of genetic backgrounds, and a frequent association with SCCmec type IV.

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Section: Discussionmentioning

confidence: 95%

Evolution of Sporadic Isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) in Hospitals and Their Similarities to Isolates of Community-Acquired MRSA

2003

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“…In the past the majority of hospital-associated methicillin-resistant strains were negative for production of superantigens capable of causing TSS and related illnesses. With the movement of community-associated methicillin-resistant strains into hospital settings, they carry with them superantigen production (such as staphylococcal enterotoxin C) (11). Very recently, two strains of S. aureus have been described that are resistant to vancomycin-in addition to being methicillin-resistant (13,37).…”

Section: Discussionmentioning

confidence: 99%

“…These latter two organisms were used in studies to assess whether or not two component systems were a target of α and β globin chains. S. aureus MW2 is a clinical isolate from a patient with necrotizing pneumonia; the organism produces the superantigen enterotoxin C (11). Group A streptococcal strain T25 3 cured(T12) produces the superantigen streptococcal pyrogenic exotoxin A (SPE A) (21).…”

Section: Experimental Procedures (Materials and Methods) Bacterial Stmentioning

confidence: 99%

α and β Chains of Hemoglobin Inhibit Production of Staphylococcus aureus Exotoxins

et al. 2007

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Prior studies suggest Staphylococcus aureus exotoxins are not produced when the organism is cultured in human blood. Human blood was fractionated into plasma and water-lysed red blood cells and demonstrated that mixtures of α and β globins of hemoglobin (as low as 1 ug/ml) inhibited S. aureus exotoxin production while increasing production of protein A and not affecting bacterial growth. Pepsin but not trypsin digestion destroyed the ability of α and β globin to inhibit exotoxin production. Exotoxin production by both methicillin-resistant and susceptible organisms was inhibited. Production of streptococcal pyrogenic exotoxin A by Streptococcus pyogenes was unaffected by α and β globin chains, but was inhibited when produced in S. aureus. Use of isogenic S. aureus strains suggested the targets of α and β globin chains, leading to inhibition of staphylococcal exotoxins, included the two component system SrrA-SrrB. Delta hemolysin production was also inhibited, suggesting the two component (and quorum sensing) system AgrA-AgrC was targeted. The α and β globin chains represent promising molecules to interfere with the pathogenesis of serious staphylococcal diseases.Staphylococcus aureus causes large numbers of human diseases, primarily initiated by colonization of mucosal surfaces (1,2). At any particular time, as many as 40% of humans may be colonized by culturable S. aureus strains on either nasal or vaginal mucosal surfaces (1,3). The organism may cause relatively benign infections, such as boils, and life threatening infections such as toxic shock syndrome (TSS) (4), scalded skin syndrome (5), necrotizing pneumonia (6-8), and the recently described staphylococcal purpura fulminans (9,10). Antibiotic resistance in S. aureus strains is an ever increasing problem, with recognition of both community-and hospital-associated methicillin-resistant strains (MRSA) (1,2,11). † This work was supported by a research grant from Procter & Gamble, Cincinnati, Ohio and USPHS research grant HL36611 from the National Heart, Lung, and Blood Institute.*To whom correspondence should be addressed. Phone: 612-624-1484; Fax: 612-626-0623; E mail: schli001@umn.edu Recently, two methicillin-resistant, vancomycin-resistant strains were isolated in association with human infections (12,13).The ability of S. aureus to cause serious human diseases depends on production of both cellsurface and secreted virulence factors by the organism (1,4). The cell-surface virulence factors, often referred to as microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) (14), allow the organism to attach to host tissues and in some instances evade the host immune system (15). MSCRAMMs include staphylococcal protein A. The secreted virulence factors, including a large array of exotoxins, allow the organism to gain access to nutrients and avoid the host immune system (4,5,16). For example, the hemolysin family of exotoxins allows the organism both to resist destruction by leukocytes and at the same time gain access to host tissue ...

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“…S. aureus, for example, exhibit a mechanism of action which protect them against almost all member of the largest family of antibiotics, the beta-lactams (ex. methicillin), which can be explained by presence of the gene mecA (Fey et al, 2003;Nascimento-Carvalho et al, 2008). P. aeruginosa has also presented increased resistance, including to imipenem, one of the antibacterial drugs with the largest spectrum of action against this pathogen .…”

Section: Antibacterial Analysis Of the Subfractions Obtained From Thementioning

confidence: 99%

Pentaclethra macroloba tannins fractions active against methicillin-resistant staphylococcal and Gram-negative strains showing selective toxicity

Leal¹,

Júnior²,

Pereira³

et al. 2011

Rev. bras. farmacogn.

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Abstract:The ethanol extract of the vegetal species Pentaclethra macroloba (Willd.) Kuntze, Fabaceae, was fractioned and the antibacterial activity was determined. The active ethyl acetate (ea) fraction showed activity against Gram-positive (Staphylococcus spp. and Enterococcus spp.) and Gram-negative (Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella pneumoniae) multiresistant bacteria. Gallic acid derivatives were identified as the main compounds in inactive subfractions from the ea fraction, while the active one afforded ellagic acid as the major constituent when submitted to acid hydrolysis reaction, which suggests the presence of hydrolysable tannins. The minimum bactericidal concentration analysis showed a bactericide mechanism of action for the tannin subfraction found. The antibacterial mechanism of action of the active tannin subfraction against S. aureus reference strains (ATCC 29213 e 33591) was proposed adopting an in vitro assay of protein synthesis inhibition. For this, bacterial cells were labeled with [ 35 S] methionine in the presence of the subfraction. The protein synthesis inhibition was observed at 256 μg/mL of this subfraction. At this concentration it did not present cytotoxicity in eukaryotic cells by the neutral red technique, suggesting selective toxicity. The present study is the first in vitro investigation of the antibacterial properties of tannin fractions obtained from a polar extract of P. macroloba.

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Comparative Molecular Analysis of Community- or Hospital-Acquired Methicillin-Resistant Staphylococcus aureus

Cited by 315 publications

References 32 publications

Evolution of Sporadic Isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) in Hospitals and Their Similarities to Isolates of Community-Acquired MRSA

Evolution of Sporadic Isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) in Hospitals and Their Similarities to Isolates of Community-Acquired MRSA

α and β Chains of Hemoglobin Inhibit Production of Staphylococcus aureus Exotoxins

Pentaclethra macroloba tannins fractions active against methicillin-resistant staphylococcal and Gram-negative strains showing selective toxicity

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