Evaluation of the BD Max MRSA
            <i>XT</i>
            Assay for Use with Different Swab Types

Dalpke, Alexander H.; Hofko, Marjeta; Stock, Christian; Zimmermann, Stefan

doi:10.1128/jcm.02306-14

Cited by 7 publications

(5 citation statements)

References 19 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dry swabs, which were used routinely at the collection site for processing on the GeneXpert test, had not been validated by any of the PCR manufacturers but come at a significantly lower price. Of interest, two independent studies also reported that the BDMAX MRSA test, in addition to the approved Liquid Stuart swabs, can be performed with other swab types, e.g., dry and ESwab with equal performance [21,28]. However, the lack of statistically different detection rates between dry and liquid swabs in our study may have been caused by the relatively low overall detection rate for MRSA despite the large number of patients screened as part of routine admission screening.…”

Section: Discussionmentioning

confidence: 70%

Liquid and dry swabs for culture- and PCR-based detection of colonization with methicillin-resistant Staphylococcus aureus during admission screening

Allmen

Gorzelniak

Liesenfeld

et al. 2019

EuJMI

View full text Add to dashboard Cite

Rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) colonization status facilitates isolation and decolonization and reduces MRSA infections. Liquid but not dry swabs allow fully automated detection methods. However, the accuracy of culture and polymerase chain reaction (PCR) using liquid and dry swabs has not been analyzed. We compared different swab collection systems for routine nasal-throat MRSA screening in patients admitted to a tertiary care trauma center in Germany. Over 3 consecutive months, dry swabs (month 1), ESwabs (month 2), or MSwabs (month 3) were processed using Cepheid GeneXpert, Roche cobas and BD-MAX™ MRSA tests compared to chromogenic culture. Among 1680 subjects, the MRSA detection rate using PCR methods did not differ significantly between dry swabs, ESwab, and MSwab (6.0%, 6.2%, and 5.3%, respectively). Detection rates using chromogenic culture were 2.9%, 3.9%, and 1.9%, using dry, ESwab, and MSwab, respectively. Using chromogenic culture as the "gold standard", negative predictive values for the PCR tests ranged from 99.2-100%, and positive predictive values from 33.3-54.8%. Thus, efficient and accurate MRSA screening can be achieved using dry, as well as liquid E-or MSwab, collection systems. Specimen collection using ESwab or MSwab facilitates efficient processing for chromogenic culture in full laboratory automation while also allowing molecular testing in automated PCR systems.

show abstract

Section: Discussionmentioning

confidence: 70%

Liquid and dry swabs for culture- and PCR-based detection of colonization with methicillin-resistant Staphylococcus aureus during admission screening

Allmen

Gorzelniak

Liesenfeld

et al. 2019

EuJMI

View full text Add to dashboard Cite

show abstract

“…The latter samples might be misclassified as MRSA in assays relying only on SCCmec rightextremity junction amplification. Indeed, for high MREJ C T values, discrepancies with culture results have been observed when singleplex MRSA assays are used, and the use of a C T value of 34 as the threshold for positivity has been suggested (14). In our study, with low MRSA prevalence, such samples were not rare (21.6%).…”

mentioning

confidence: 71%

Evaluation of the BD Max StaphSR Assay for Rapid Identification of Staphylococcus aureus and Methicillin-Resistant S. aureus in Positive Blood Culture Broths

et al. 2015

Self Cite

View full text Add to dashboard Cite

bWe evaluated the performance of the BD Max StaphSR assay for the direct detection of Staphylococcus aureus from blood culture medium. In a two-center trial, 155 blood cultures from the BD Bactec FX system and 212 from the bioMérieux BacT/Alert system were tested; 170 bottles yielded S. aureus, and all were identified correctly by the BD Max StaphSR assay. The assay required approximately 2.5 h, thus allowing rapid identification of blood cultures flagged positive. The BD Max StaphSR assay (BD, Quebec, Canada) is a fully automated, qualitative, in vitro diagnostic test for the direct detection of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in patients at risk for nasal colonization. The test uses real-time PCR for the amplification of three DNA targets, i.e., SCCmec right-extremity junction (MREJ), thermostable nuclease (nuc), and methicillin resistance (mecA and mecC). Positivity for MREJ and mecA/mecC is required for the result "MRSA," and detection of nuc or MREJ without mecA/mecC is interpreted as "positive for S. aureus." The BD Max StaphSR assay was shown to have excellent sensitivity (96.4%) and specificity (93.6%), compared to combined direct and enriched cultures, for detection of S. aureus from anterior nares samples (1). In this study, we tested the performance of the StaphSR assay with a different sample type, namely, positive blood culture medium with Gram-positive cocci in clusters.Bloodstream infections often result in the need for intensive care and are associated with high mortality rates and large economic burdens (2). S. aureus is one of the main causes of bloodstream infections (3, 4). Rapid identification of positive blood cultures is a prerequisite for timely targeted treatment of patients with sepsis (5-7). Quick differentiation of S. aureus from coagulase-negative Staphylococcus (CoNS) can reduce the costs of patient care and decrease hospitalization times (8). The use of molecular assays for direct detection of S. aureus in blood culture bottles has been shown to allow rapid diagnosis of S. aureus septicemia, which might improve patient treatment (6, 9, 10). The recently introduced BD Max system allows fully automated realtime PCR, but the currently available BD Max StaphSR assay is CE marked and FDA cleared only for use with nasal swabs (11).In a first stage, we tested the use of the StaphSR assay with blood culture bottles (Bactec Plus Aerobic/F or Bactec Plus Anaerobic/F) that had been artificially inoculated with 1,000 CFU of MRSA, methicillin-susceptible S. aureus (MSSA), or methicillinresistant coagulase-negative Staphylococcus (MR-CoNS). After bottles were flagged positive, aliquots from those bottles were tested by inoculating the sample buffer tube (SBT) of the assay.The blood culture bottles were tested again after an additional 18 to 24 h of incubation, to mimic delayed analysis and to ensure that high DNA levels did not result in competition with any of the PCR target amplifications. We tested three volumes, i.e., 15, 50, and 100 l. All spiked blood cultu...

show abstract

“…A total of 255 clinical samples were collected for routine MRSA screening from the nares of patients using anterior nares ESwab (Copan Diagnostics, Murrieta, CA). The use of the ESwab with BD Max assays is outside the claims in the package insert; however, its use with the BD Max MRSA first-generation assay was validated in previous studies (22,23).…”

Section: Methodsmentioning

confidence: 99%

“…Both assays utilize real-time PCR and fluorogenic target-specific hybridization probes to detect the SCCmec right-extremity junction (MREJ) and mecA and mecC genes (20)(21)(22). The BD Max StaphSR assay also detects the nuc gene encoding a thermostable nuclease of S. aureus, which allows the assay to detect all S. aureus, including MRSA (21).…”

mentioning

confidence: 99%

Evaluation of BD Max StaphSR and BD Max MRSA XT Assays Using ESwab-Collected Specimens

et al. 2015

View full text Add to dashboard Cite

The BD Max MRSAXT and the BD Max StaphSR assays were validated for the detection of methicillin-resistant Staphylococcus aureus (MRSA) in ESwab samples. In addition, the BD Max StaphSR assay was evaluated for its ability to detect and differentiate S. aureus and MRSA in the same sample. A total of 255 ESwab samples collected from the anterior nares of patients were tested by each of three BD Max assays, including the BD Max MRSA first-generation assay. The results were compared to those of direct and enrichment culture. Additionally, a challenge panel comprising 14 control strains was evaluated to determine the ability of these assays to correctly identify MRSA and also appropriately differentiate S. Staphylococcus aureus is a leading cause of health care-associated infections. Infection due to S. aureus imposes a high and increasing burden on health care resources and increases morbidity and mortality. Nasal carriage of S. aureus has been identified as a risk factor for the development of infections in various settings. This has been studied extensively in surgical patients (general, orthopedic, and thoracic surgery), patients on hemodialysis, patients on continuous ambulatory peritoneal dialysis (CAPD), HIV-infected patients, and patients in intensive care units (1, 2). Methicillin-resistant S. aureus (MRSA) is an important cause of community-acquired and hospital-acquired infections (3, 4). MRSA can colonize the nares, skin, and other body sites, serving as a reservoir for infection and transmission in health care environments (5-7). Screening for MRSA colonization in order to help identify patients at greater risk for MRSA infection and to allow for the initiation of isolation precautions has become standard practice in many institutions (5,6,(8)(9)(10).MRSA screening using molecular amplification methods provides faster results than culture and has been demonstrated to be more sensitive (11-15). However, most of the molecular commercially available rapid tests are based on the detection of a sequence indicating the integration of the staphylococcal cassette chromosome mec element (SCCmec) within the chromosome and do not specifically target the methicillin resistance gene mecA (16). S. aureus isolates with an SCCmec lacking the mecA gene have been described and can be incorrectly identified as MRSA by assays that do not specifically target the mecA gene (17). False-positive results can lead to unnecessary and expensive isolation and treatment of patients. In addition, MRSA strains with the newly discovered methicillin resistance gene mecC account for 3 to 4% of all new MRSA cases in Denmark (18) and cannot be detected by assays that do not detect the mecC gene (19). These false-negative results can lead to uncontrolled transmission of undetected MRSA strains.The BD Max StaphSR and the BD Max MRSAXT assays (BD Diagnostics, Québec, Canada) performed on the BD Max system (BD Diagnostics, Sparks, MD) are next-generation automated qualitative in vitro diagnostic tests able to detect MRSA strains harboring the m...

show abstract

Evaluation of the BD Max MRSA XT Assay for Use with Different Swab Types

Cited by 7 publications

References 19 publications

Liquid and dry swabs for culture- and PCR-based detection of colonization with methicillin-resistant Staphylococcus aureus during admission screening

Liquid and dry swabs for culture- and PCR-based detection of colonization with methicillin-resistant Staphylococcus aureus during admission screening

Evaluation of the BD Max StaphSR Assay for Rapid Identification of Staphylococcus aureus and Methicillin-Resistant S. aureus in Positive Blood Culture Broths

Evaluation of BD Max StaphSR and BD Max MRSA XT Assays Using ESwab-Collected Specimens

Contact Info

Product

Resources

About