Automated Systems Extraction with Amplification

Roche (Roche Molecular Biochemical, Indianapolis, IN, USA) has three automated instruments. The MagNA Lyser Instrument is an automated tissue homog-enization unit that can be combined with their automated nucleic acid extractors. For nucleic acids, there is the MagNA Pure Compact and the MagNA Pure LC. The MagNA Pure Compact has a small footprint and can extract nucleic acids from 1 to 8 samples, using 2 different compact nucleic acid kits for small and large volumes. The MagNA Pure LC can process up to 32 samples in 1 to 3 h. The LC model automates both extraction and PCR set-up for the LightCycler capillaries, COBAS A-rings, and 96-well plates or tubes. The MagNA Pure LC has been evaluated with bacteria, parasites, fungi, DNA viruses, and RNA viruses; it was found to be equivalent to manual methods (Espy et al., 2001; Loeffler et al., 2002; Wolk et al., 2002; Germer et al., 2003; Holzl et al., 2003; Knepp et al., 2003; Leb et al., 2004; Lee et al., 2003; Cook et al., 2004; Dalesio et al., 2004; Muller et al., 2004; Tang et al., 2005). The COBAS Ampliprep is an automated system for the Cobas Amplicor analyzer and is not available in the United States except for research purposes. The COBAS Ampliprep has been reported in the literature to be suitable for routine testing with decreased hands-on time (Gartner et al., 2004; Stelzl et al., 2004). The next-generation COBAS, the COBAS TaqMan 48, is now available and has the capacity to run two different assays with individual PCR profiles. The LightCycler 2.0 system is also available, which allows 6-dye channel detection instead of the previous 4-dye channel detection.

Biomerieux (Biomerieux, Marcy l'Etoile, France) has three systems for nucleic acid extraction: the Nuclisens Extractor, which uses silica dioxide Boom extraction protocol (Boom et al., 1990), and the NucliSens easyMAG and the NucliSens miniMAG, which both use magnetic silica. The Nuclisens Extractor is an automated closed system. It has been compared to Qiagen manual extraction and found to be efficient for extraction of viral DNA and RNA (Gobbers et al., 2001). The easyMAG is an automated magnetic silica extraction system that will extract 24 samples in less than an hour. The miniMAG is a manual system that can extract 12 samples in about 35 min and offers a low-cost extraction system to a smaller molecular laboratory. Recent studies have suggested that the miniMAG consistently provides high yields of low titer of target (Tang et al., 2005). These systems are designed to extract both DNA and RNA for use with either Nucleic Acid Sequence-Based Identification (NASBA) or PCR amplification technologies. The NucliSens Easy Q can also be coupled with these extraction methods for detection with real-time NASBA. The miniMAG has been used with the EasyQ real-time NASBA HIV assay to accurately quantify HIV over a six-log range.

Applied Biosystems (ABI; Foster City, CA, USA) has two nucleic acid extraction systems, which use proprietary flow-through chemistry. The ABI PRISM 6100 nucleic acid prep station can program up to 300 defined extraction protocols. The ABI PRISM 6700 Automated Nucleic Acid Workstation is a fully automated system that extracts nucleic acid, prepares the PCR reactions, and initiates the reverse transcription step of RT-PCR for up to 96 samples. The ABI Prism 6700 was used to automate the large-scale surveillance of West Nile virus during outbreaks in the northeastern United States (Shi et al., 2001). This workstation can interface with the existing ABI PCR instruments, the ABI PRISM 7900HT, 7500, 7300, 7000, and GeneAmp 5700.

Corbett Research (distributed by Phenix Research Products, Hayward, CA, USA) offers two separate automated instruments, the X-Tractor Gene for RNA/DNA extraction and the CAS-1200 liquid handling system for set-up of both standard and real-time PCR reactions. The CAS-1200 can be configured to support 96-well plates or the Rotor-Gene well rotors for use with the Rotor-Gene 3000, a four-channel real-time PCR fluorescent detector.

Becton Dickinson (BD, Franklin Lakes, NJ, USA) has an automated sample processor for the BDProbeTec ET system. The BD Viper Sample Processor is designed to automate sample processing with high-volume testing of Neisseria gonorrhoeae and Chlamydia trachomatis (>500 samples/8-h shift). Gen-Probe (Gen-Probe Incorporated, San Diego, CA, USA) has launched the TIGRIS, which is a fully automated instrument for high-volume testing (1000 samples/12-h shift). The TIGRIS incorporates Gen-Probe's target capture technology for sample processing, Transcription-mediated Amplification (TMA) amplification, and Hybridization Protection Assay (HPA) detection into one instrument. Currently, the TIGRIS is limited to use with Gen-Probe's APTIMA N. gonorrhoeae/C. trachomatis assay and Procleix HIV/HCV blood screening assay. Gen-Probe also offers the DTS 800 and 1600 systems (manufactured by Tecan, Research Triangle Park, NC, USA), which automate the liquid handling of other various diagnostic kits. Abbott (Abbott

Laboratories, Abbott Park, IL, USA) is developing an automated sample preparation workstation. The m1000 is designed to process 48 samples in 2 h using a magnetic microparticle-based protocol and has been reported by Abbott to be integrated with the ABI PRISM 7000 detection systems.

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