Conventional and Molecular Methods for the Detection of Methicillin-Resistant Staphylococcus aureus

Marlowe, Elizabeth M.; Bankowski, Matthew J.

doi:10.1128/jcm.00791-11

Cited by 46 publications

(41 citation statements)

References 25 publications

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“…Rapid molecular methods of MRSA detection are increasingly used and are available for testing from a variety of sources. 54 Traditional detection of MRSA from automated blood culture instruments is timeconsuming because 24 to 72 hours are required for subculture, biochemical identification, and AST of the isolate once the result turns positive. Several techniques are available for identification of MRSA directly from blood culture bottles that have flagged as positive for growth when gram-positive cocci in clusters are seen on Gram stain.…”

Section: Detection Of Methicillin Resistance In Staphylococcus Sppmentioning

confidence: 99%

Current Concepts in Laboratory Testing to Guide Antimicrobial Therapy

Jenkins

Schuetz

2012

Mayo Clinic Proceedings

174

133

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Antimicrobial susceptibility testing (AST) is indicated for pathogens contributing to an infectious process that warrants antimicrobial therapy if susceptibility to antimicrobials cannot be predicted reliably based on knowledge of their identity. Such tests are most frequently used when the etiologic agents are members of species capable of demonstrating resistance to commonly prescribed antibiotics. Some organisms have predictable susceptibility to antimicrobial agents (ie, Streptococcus pyogenes to penicillin), and empirical therapy for these organisms is typically used. Therefore, AST for such pathogens is seldom required or performed. In addition, AST is valuable in evaluating the activity of new and experimental compounds and investigating the epidemiology of antimicrobial resistant pathogens. Several laboratory methods are available to characterize the in vitro susceptibility of bacteria to antimicrobial agents. When the nature of the infection is unclear and the culture yields mixed growth or usual microbiota (wherein the isolates usually bear little relationship to the actual infectious process), AST is usually unnecessary and results may, in fact, be dangerously misleading. Phenotypic methods for detection of specific antimicrobial resistance mechanisms are increasingly being used to complement AST (ie, inducible clindamycin resistance among several gram-positive bacteria) and to provide clinicians with preliminary direction for antibiotic selection pending results generated from standardized AST (ie, ␤-lactamase tests). In addition, molecular methods are being developed and incorporated by microbiology laboratories into resistance detection algorithms for rapid, sensitive assessment of carriage states of epidemiologically and clinically important pathogens, often directly from clinical specimens (ie, presence of vancomycin-resistant enterococci in fecal specimens).

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Section: Detection Of Methicillin Resistance In Staphylococcus Sppmentioning

confidence: 99%

Current Concepts in Laboratory Testing to Guide Antimicrobial Therapy

Jenkins

Schuetz

2012

Mayo Clinic Proceedings

174

133

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“…These assays were promising initially, but subsequent data revealed a variety of performance-related challenges. 8 The KeyPath MRSA/MSSA blood culture test (MMBT, MicroPhage, Inc, Longmont, Colorado) is a US Food and Drug Administration (FDA)-approved, nonmolecular, rapid test that detects MSSA and MRSA directly from blood culture tests using bacteriophage-amplification technology. This study examined the diagnostic performance of MMBT in the detection of MSSA and MRSA bacteremia in a tertiary pediatric population.…”

mentioning

confidence: 99%

Rapid Detection of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin-Susceptible Staphylococcus aureus (MSSA) Using the KeyPath MRSA/MSSA Blood Culture Test and the BacT/ALERT System in a Pediatric Population

Sullivan

Turner

Roundtree

et al. 2013

Archives of Pathology &Amp; Laboratory Medicine

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Context.-Timely initiation of directed antimicrobial therapy for Staphylococcus aureus bacteremia is dependent on rapid identification of S aureus to ascertain methicillin-susceptibility status.Objective.-To investigate the performance of the rapid KeyPath (MicroPhage, Inc, Longmont, Colorado) methicillin-resistant S aureus (MRSA) and methicillin-susceptible S aureus (MSSA) blood culture test (MMBT).Design.-Positive BacT/ALERT Pediatric FAN (fastidious antibiotic neutralization) blood culture bottles (bioMérieux, Inc, Durham, North Carolina) were tested prospectively using MMBT and routine bacterial identification and antibiotic susceptibility testing procedures as the gold standard. The MMBT uses an S aureus-specific bacteriophage cocktail that infects bacterial cells and replicates them, resulting in cellular lysis. Bacteriophagespecific antibodies detect the increase in bacteriophage concentration in an immunoassay device. Phage amplification, in both the presence and absence of cefoxitin, indicates the presence of MRSA. The sensitivity, specificity, positive predictive value, and negative predictive value of MMBT in detecting S aureus, MSSA, and MRSA were calculated.Results.-Of 188 positive blood cultures tested, 199 (63%) had Gram-positive cocci in clusters, 46 (24%) grew S aureus (26 MSSA [57%], 20 MRSA [43%]) with the MMBT detecting 40 of 46 (87%). The sensitivity, specificity, positive predictive value, and negative predictive value among blood cultures with Gram-positive cocci in clusters were 87%, 100%, 100%, and 92% for S aureus; 81%, 100%, 100%, and 95% for MSSA; and 95%, 100%, 100%, and 99% for MRSA. All blood cultures without growth of S aureus tested negative by MMBT.Conclusions.-The MMBT detected MSSA and MRSA directly from positive BacT/ALERT PF bottles with positive predictive values of 100%, suggesting that positive results could be reported immediately, but the sensitivity of this assay limited immediate reporting of negative results.

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“…Metisilin direncinin kesin tanısı PZR ile mecA geninin gösterilmesiyle konulsa da bu yöntem hem donanımlı bir laboratuvar ortamı hem de eğitimli personel gerektirdiğinden rutinde kullanımı zor bir yöntemdir (11) . Bu nedenle MRSA doğru tanısını konvansiyonel yöntemlerle koymak ayrı bir önem taşımaktadır.…”

Section: Discussionunclassified