Molecular Epidemiology of Methicillin-Resistant<i>Staphylococcus aureus</i>, Rural Southwestern Alaska1

David, Michael Z.; Rudolph, Karen; Hennessy, Thomas W.; Boyle-Vavra, Susan; Daum, Robert S.

doi:10.3201/eid1411.080381

Cited by 37 publications

(30 citation statements)

References 33 publications

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“…USA400 was also identified in the community in 1999 to 2002 in Saskatchewan, Canada (640), and in 1995 to 2000 in Manitoba, Canada (1017). USA400 remained the predominant genotypic background of CA-MRSA strains in rural southwestern Alaska in 2004 to 2006 (218). Despite the ability of USA400 to cause severe, invasive disease, soon after 2000 it was replaced by USA300 as the predominant CA-MRSA strain in most regions of the United States (309) and later in parts of Canada (1027).…”

Section: Other Prominent Ca-mrsa Genetic Backgroundsmentioning

confidence: 96%

Community-Associated Methicillin-ResistantStaphylococcus aureus: Epidemiology and Clinical Consequences of an Emerging Epidemic

2010

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SUMMARY Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

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Section: Other Prominent Ca-mrsa Genetic Backgroundsmentioning

confidence: 96%

Community-Associated Methicillin-ResistantStaphylococcus aureus: Epidemiology and Clinical Consequences of an Emerging Epidemic

2010

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“…HA-MRSA isolates generally belong to USA100, USA200, and USA500 (34,35). One of the two major clones of CA-MRSA, USA400, recognized in the early 1990s and initially referred to as the MW2 clone, was the predominant CA-MRSA clone that initially circulated in the midwestern United States in the 1990s (8,17,40,52). The second and more recent CA-MRSA clone, USA300, was first recognized in 2000 and has since spread throughout the world (54).…”

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confidence: 99%

Virulence Genes and Genotypic Associations in Nasal Carriage, Community-Associated Methicillin-Susceptible and Methicillin-Resistant USA400 Staphylococcus aureus Isolates

et al. 2010

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It is not well understood why strains of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), a major cause of skin and soft tissue infections, became successful so quickly, overtaking the place of methicillin-sensitive S. aureus (MSSA) in many communities. To evaluate the genetic basis of differences in their virulence traits, 293 S. aureus isolates consisting of three cohorts, genotypically defined clinical CA-MRSA (n ‫؍‬ 77), clinical MSSA (n ‫؍‬ 103), and nasal carriage MSSA (n ‫؍‬ 113), collected over a 19-year period in two Midwestern states in the United States, were (i) extensively genotyped and (ii) screened for 40 known virulence genes which included those for enterotoxins, leukocidins, hemolysins, and surface proteins and several newly identified putative toxin genes from the USA400 lineage of CA-MRSA. Genotypically, nasal carriage and clinical MSSA isolates were much more diverse than was the CA-MRSA group, which was found to be of USA400 lineage only. Virulence gene profiles of the three groups showed that CA-MRSA strains harbored significantly higher percentages (>95%; P value, <0.05) of the sea, sec, sec4, seg2, seh, sek, sel, sel2, ear, ssl1, lpl10, lukSF-PV, lukD, lukE, and clfA genes than did the carriage and the clinical MSSA group (range, 0% to 58%). Genes of the enterotoxin gene cluster, seg, sei, sem, sen, and seo, were present in the clinical and carriage isolates but not in the CA-MRSA group. These results suggest that the presence of additional virulence factors in USA400 CA-MRSA strains compared to the nasal carriage and clinical MSSA strains probably contributed to their enhanced virulence.

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“…The BD GeneOhm MRSA assay was tested with 914 MRSA culture isolates. Nine hundred six of these were stored in our collection as part of ongoing surveillance of MRSA in the years spanning 1995 to 2006, as described previously (5)(6)(7)(8) (NARSA). In addition, we included the SCCmec type VI typing strain from Herminia deLencastre from Portugal (0.1%).…”

Section: Methodsmentioning

confidence: 99%

Reliability of the BD GeneOhm Methicillin-Resistant Staphylococcus aureus (MRSA) Assay in Detecting MRSA Isolates with a Variety of Genotypes from the United States and Taiwan

Boyle-Vavra

Daum

2010

J Clin Microbiol

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The BD GeneOhm methicillin-resistant Staphylococcus aureus (MRSA) assay is a molecular screening test for detection of MRSA in nasal colonization. This assay coamplifies the extremity of staphylococcal chromosome cassette mec (SCCmec) and adjacent chromosomal DNA at the SCCmec insertion site. Increasing reports of novel SCCmec types and the diverse genetic backgrounds of MRSA strains prompted us to test the accuracy of the BD GeneOhm MRSA kit with 914 MRSA isolates with a variety of SCCmec types harbored in 21 genetic backgrounds, as determined by the multilocus sequence type (ST). The BD GeneOhm MRSA assay was performed on colony lysates; purified genomic DNA (0.2 pg/l and 0.2 ng/l) was tested to confirm negative results from lysates. Of 914 MRSA isolates tested, 911 tested positive (detection rate, 99.7%). The SCCmec types carried by assay-positive isolates were I, II, III, IV, V, V (5C2&5) , VI, and VIII and SCCmec composite islands with mec class A and ccr complexes 2 and 4. One of the assay-negative isolates had a communityassociated genotype: ST8, SCCmec type IV. However, this was an outlier among the 99.8% (434/435) ST8, SCCmec type IV-containing isolates that tested positive. The two other assay-negative isolates had a health care-associated genotype (ST5); both carried a distinct, uncommon, composite SCCmec type. In summary, the BD GeneOhm MRSA assay had a high rate of detection of MRSA isolates harboring common and uncommon SCCmec types from the United States and Taiwan.

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Molecular Epidemiology of Methicillin-ResistantStaphylococcus aureus, Rural Southwestern Alaska1

Cited by 37 publications

References 33 publications

Community-Associated Methicillin-ResistantStaphylococcus aureus: Epidemiology and Clinical Consequences of an Emerging Epidemic

Community-Associated Methicillin-ResistantStaphylococcus aureus: Epidemiology and Clinical Consequences of an Emerging Epidemic

Virulence Genes and Genotypic Associations in Nasal Carriage, Community-Associated Methicillin-Susceptible and Methicillin-Resistant USA400 Staphylococcus aureus Isolates

Reliability of the BD GeneOhm Methicillin-Resistant Staphylococcus aureus (MRSA) Assay in Detecting MRSA Isolates with a Variety of Genotypes from the United States and Taiwan

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