Comparison of four methods for rapid identification of Staphylococcus aureus directly from BACTEC 9240 blood culture system

The identification of Staphylococcus aureus directly from blood cultures is clinically relevant, but it requires a test that is both rapid and reliable. Previously, biochemical, immunological, tube coagulase, and thermostable-endonuclease methods have shown variable sensitivity and specificity. Testing directly from blood culture broth has not been described for the latex kit Staphaurex Plus (Murex Diagnostics Ltd.), and the modified conventional tests have not been used with the newer, continuously monitored blood culture systems. In addition, the commercial RAPIDEC staph kit (bioMerieux Vitek, Inc.) has been used to detect S. aureus directly from the Vital blood culture system (bioMerieux, Marcy l’Etoile, France), but its performance has not been evaluated with other continuously monitored systems. A total of 201 clinical blood cultures (BACTEC 9240 culture system; Johnston Laboratories, Inc.) in which a Gram stain showed gram-positive cocci resembling staphylococci were evaluated prospectively. The Staphaurex Plus kit, the tube coagulase test, the thermostable-endonuclease test, and the RAPIDEC staph kit were compared. The sensitivities were 23, 92, 85, and 98% and the specificities were 99, 100, 93, and 100%, respectively. The RAPIDEC staph kit was the most reliable test, with a diagnostic accuracy comparable to that of the best published results for any of the rapid tests. However, it was the most expensive of the tests and relatively labor-intensive. The tube coagulase test was also sensitive, the simplest to perform, and inexpensive.

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292. Impact of the BACT/ALERT VIRTUO blood culture system in the management of Staphylococcus aureus bacteremia

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.335 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S145-S146

Author(s):

Miguel A Chavez ◽

Satish Munigala ◽

Carey-Ann Burnham ◽

David K Warren

Keyword(s):

Staphylococcus Aureus ◽

Blood Culture ◽

Median Time ◽

Culture System ◽

Source Control ◽

Similar Proportion ◽

Blood Culture System ◽

Staphylococcus Aureus Bacteremia ◽

Time To Positivity ◽

Implementation Period

Abstract Background Staphylococcus aureus bacteremia (SAB) is a major cause of mortality. Recovery of SA may be enhanced with new blood culture systems resulting in a longer observed duration of bacteremia. Methods We performed a 24-month retrospective study of adults hospitalized with SAB at a 1250-bed academic hospital. Between 1/2018-12/2018 the VersaTREK system was used and 1/2019-12/2019 the BACT/ALERT VIRTUO (VIRTUO) system was used. We excluded patients without an Infectious Diseases (ID) consult. We defined SAB duration as short (1–2 days), intermediate (3–6 days), or prolonged (>7 days). We compared SAB detection and management pre- and post-implementation of VIRTUO. Results 456 patients had SAB during study period; 420 (92%) had ID consultation: 178 (42%) pre- and 242 (58%) post-implementation. Similar proportion of methicillin-resistant SAB was seen (44.9% pre- vs. 36.8% post-implementation, p=0.09). Post-implementation, patients were more likely to have intermediate (22.4% pre- vs. 40.1% post-implementation; p< 0.001) and prolonged SAB duration (3.9% pre- vs. 13.6% post-implementation; p< 0.001). Median time to positivity for the index blood culture was shorter (19.9 pre- vs. 15.0 hours post-implementation, p< 0.001). Dual anti-staphylococcal therapy was used more frequently in the post-implementation period (6.2% pre- vs. 15.7% post-implementation, p=0.003). No difference was noted in frequency of diagnostic studies (transesophageal echocardiography, magnetic resonance imaging, and computed tomography). Source control was similar (46.1% pre- vs. 45.0% post-implementation; p=0.84) but the median time to source-control was shorter post-implementation (4 pre- vs. 2 days post-implementation; p=0.02). Median planned duration of intravenous antibiotics did not vary between pre- and post-implementation periods (6 vs. 6 weeks, p=0.31). There was no difference in 90-day readmissions (38.2% pre- vs. 34.3% post-implementation; p=0.41). Conclusion VIRTUO blood culture system decreased time to positivity and increased frequency of prolonged SAB compared to the VersaTREK system. This resulted in increased use of dual anti-staphylococcal therapy and shorter time to source-control, but no difference in interventions, planned duration of antibiotics, or readmissions. Disclosures All Authors: No reported disclosures

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Two Epidemics of Pseudobacteremia Due to Staphylococcus aureus and Aerococcus viridans

Infection Control ◽

10.1017/s0195941700053261 ◽

1980 ◽

Vol 1 (5) ◽

pp. 321-323 ◽

Cited By ~ 9

Author(s):

Martin L. Spivack ◽

Robert Shannon ◽

George A. Natsios ◽

Jan Wood

Keyword(s):

Staphylococcus Aureus ◽

Blood Culture ◽

Culture System ◽

Skin Infection ◽

Blood Culture Bottle ◽

Nasal Colonization ◽

Culture Bottle ◽

Blood Culture System ◽

Aerococcus Viridans ◽

Staphyloccus Aureus

AbstractTwo epidemics of pseudobacteremia are reported. The first, due to Staphyloccus aureus, was caused by a physician who had active staphylococcal skin infection and nasal colonization. Because the blood culture system in use at the time was open, and used screw cap bottles, we assume that the physician contaminated the bottles at the time of inoculation. The second outbreak, caused by Aerococcus viridans, was traced to contamination of the blood culture bottle tops as they were received from the manufacturer. We assume that there was inadequate disinfection of the bottle tops by the physicians prior to their use.

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Mortality Rate and Magnitude of Staphylococcus aureus Bacteremia as Assessed by a Semiquantitative Blood Culture System

Scandinavian Journal of Infectious Diseases ◽

10.3109/00365549509018967 ◽

1995 ◽

Vol 27 (1) ◽

pp. 19-21 ◽

Cited By ~ 6

Author(s):

Henrik C. Schønheyder ◽

Adam Gottschau ◽

Anne Friland ◽

Vibeke Thamdrup Rosdahl

Keyword(s):

Staphylococcus Aureus ◽

Mortality Rate ◽

Blood Culture ◽

Culture System ◽

Blood Culture System ◽

Staphylococcus Aureus Bacteremia

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2171. Phenotypic Correlations for the Presence of CTX-M in Enterobacteriaceae and mecA in Staphylococcus aureus using the Verigene® Blood Culture System

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1851 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S737-S737

Author(s):

Nigo Masayuki ◽

Audrey Wanger ◽

Cesar A Arias

Keyword(s):

Blood Culture ◽

Sensitivity And Specificity ◽

Culture System ◽

Bloodstream Infections ◽

High Sensitivity ◽

Final Analysis ◽

Rapid Identification ◽

Blood Culture System ◽

Oxacillin Resistance ◽

Phenotypic Susceptibility

Abstract Background Rapid identification of antimicrobial resistance markers has the potential to help targeting antimicrobial therapy and enhance efforts for antibiotic stewardship. However, limited data are available to correlate phenotypic and genotypic results for some of these platforms in positive blood cultures (BC). Here, we aimed to evaluate the ability of the Verigene® (VG) Blood Culture System to predict phenotypic susceptibility patterns with the detection of the genes encoding the CTX-M in Enterobacteriaceae and MecA in S. aureus (SA) in a large dataset. Methods Phenotypic susceptibility and VG results were retrospectively collected between August 2017 and December 2018 from 12 hospitals in Houston, TX. VG testing was performed on only the first isolate was considered in persistent positive BCs. The VG report of the presence of blaCTX-M or mecA was correlated with phenotypic susceptibility to ceftriaxone (CTO) (E. coli [EC] and Klebsiella spp.[KL]) or oxacillin (SA), respectively. Results We identified a total of 5,937 VG results. The final analysis was performed on 2,356 cases where EC, KL or SA was identified. Isolates detected KPC and NDM by VG were excluded. 30 EC/KL were missed by VG in polymicrobial bacteremia. 7 polymicrobial positive BCs with coagulase-negative staphyloccocci were mislabeled as MecA positive MSSA. Among isolated detected by VG, there were the high sensitivity and specificity of CTX-M to identify CTO resistance (97.2% and 99.7% in EC and 91.4% and 99.2% in KL). For SA, the sensitivity and specificity of mecA were 100% and 99.6% to identify oxacillin resistance. 2 isolates with mecA positive by VG were reported as oxacillin-suscpetible. Conclusion Our results revealed that there is a high correlation between VG and phenotype. For SA, discrepancies between genotype and phenotype seem to be influenced by the presence of other organisms in the sample. Genotypic information seems reliable and should guide targeted therapy in bloodstream infections. Disclosures All authors: No reported disclosures.

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