Assessment of screening practices in a subacute clinical setting following introduction of Trichomonas vaginalis nucleic acid amplification testing.

OBJECTIVE: Trichomonas vaginalis analyte-specific reagent is a highly sensitive assay for T vaginalis detection. We report how this diagnostic innovation influenced the sexually transmitted infection ordering practice patterns of 20 subacute-care clinicians. METHODS: T vaginalis, Neisseria gonorrhoeae, and/or Chlamydia trachomatis screening data were audited on female swab submissions when only wet mount testing was available for detection of T vaginalis (2004-2007) and when T vaginalis detection options included analyte-specific reagent and wet mount (2008-2010). RESULTS: Analyte-specific reagent availability resulted in more screening and detection of T vaginalis, prompted less utilization of wet mount microscopy, and increased overall RNA-based screening for N gonorrhoeae and C trachomatis (P < 0.0002). CONCLUSION: Clinician familiarity with T vaginalis analyte-specific reagent can benefit both clinical practice and public health.

Cost-effective modification of a commercial PCR assay for detection of methicillin-resistant or -susceptible Staphylococcus aureus in positive blood cultures.

Real-time detection of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in cases of clinical bacteremia may promote appropriate antimicrobial therapy and infection control. Expense inherent to molecular diagnostics may prevent laboratories from utilizing real-time PCR for this purpose. BD GeneOhm StaphSR assay master mix was reconstituted and aliquoted into SmartCycler tubes in 25-mul volumes (freshly reconstituted master mix), with a portion being frozen at -70 degrees C (frozen master mix). Incubation of 40 previously analyzed lysates from positive BacT/Alert SA and SN blood culture bottles (identified as 10 MRSA strains, 10 MSSA strains, 12 coagulase-negative Staphylococcus strains, and 8 Micrococcus strains) in freshly reconstituted master mix and master mix frozen between 1 week and 6 months generated the expected results in all PCRs. Similarly, positive- and negative-control reagents stored frozen at -70 degrees C for up to 18 weeks yielded the expected reactions. Prospective analysis of 244 positive blood culture samples utilizing 1-week-frozen master mix and freshly reconstituted master mix yielded a 1.2% discordant rate upon initial testing due to three unresolved results (two unresolved results for freshly reconstituted master mix and one unresolved result for frozen master mix). Repeat testing produced a final 100% concordance rate between the two master mix preparations. Use of master mix that was frozen up to 6 months did not compromise performance of the BD GeneOhm StaphSR assay. This modification, resulting in less reagent waste, may allow a greater number of laboratories to consider real-time PCR methodology for detection of bacteremia caused by MRSA and MSSA.