As health providers move toward universal methicillin-resistant (MRSA) screening for hospital
May 13, 2017
As health providers move toward universal methicillin-resistant (MRSA) screening for hospital admissions the most cost-effective approach is yet to be defined. patient note review. A total of 1 1 428 pooled MRSA screens were tested. Sensitivities and specificities of 85.3% and 95.8% for the Rotor-Gene and 81% and 95.7% for the Smart-Cycler were obtained compared with broth enrichment. The sensitivity of the BD GeneOhm assay was increased to 100% when the results of in-house PCR and patient note review were taken into account. This study demonstrates that this Rotor-Gene 6000 thermal cycler is usually a reliable platform for use with the BD GeneOhm assay. It also proves that commercial PCR can be performed direct on pooled samples in selective broth without the need for overnight incubation. Screening assessments have recently been introduced that detect single molecular targets specific to methicillin-resistant (MRSA) (21 23 These offer significant advantages over culture which takes 2 to 5 days to produce a positive result and their use has been associated with reduced transmission of MRSA in both intensive care unit (ICU) and surgical settings (4 11 12 One of the most widely used commercial displays the BD GeneOhm MRSA assay (BD Diagnostics Becton Dickinson NJ) concurrently detects goals in the staphylococcal cassette chromosome (SCCgenes. It’s been examined for make use of on specific swabs extracted from sinus and extranasal sites and from pooled TBC-11251 examples using the Smart-Cycler II (Cepheid Sunnyvale CA) PCR format (2 6 14 Using the adoption of general MRSA verification for medical center admissions (5) nevertheless TBC-11251 the volume of examples is set to improve significantly necessitating an assessment of substitute higher-throughput platforms. The purpose of the present research was to judge the performance from the BD GeneOhm MRSA assay in the Rotor-Gene 6000 thermal cycler for the recognition of MRSA in pooled swabs from multiple sites weighed against the same assay in the Smart-Cycler II. Outcomes were weighed against those from broth-based lifestyle. Examples yielding discrepant outcomes were put through further evaluation using an in-house PCR and individual be aware review (NR). Components AND METHODS The analysis was executed at Kings University Medical center a 940-bed London teaching medical center in South London Britain. Specimen collection and processing. Routine MRSA screening TBC-11251 swabs were taken from patients being admitted to or resident in our hospital. Unlike many previous studies there was no preselection of samples according to previous MRSA status or patient type (2 6 14 The sites sampled included anterior nares groin/perineum and throat in addition to skin breaks/wounds and indwelling device insertion sites where appropriate. Either Stuart’s or Amies medium (Copan Diagnostics Italy) with or without charcoal was utilized for transport of swabs (14). To minimize sampling error at sites with low bacterial counts we avoided the use of double-headed or duplicate swabs. Culture. Pooled swabs from individual patients were inoculated into 5 ml selective mannitol broth (product code EB1016C; Oxoid Ltd.). After overnight incubation at 37°C broths with a positive chromogenic indication change on visual inspection (approximately 40% of the total) were subcultured onto Brilliance MRSA agar (product code P011621A; Oxoid Ltd.). After at least 18 h of incubation at TBC-11251 37°C “denim blue” TBC-11251 colonies were identified by standard methodology (13). LoD screening. For limit of detection (LoD) screening a laboratory strain of MRSA was cultured overnight at 37°C to late log phase (108 to 109 CFU/ml). Log dilutions were made in nutrient broth (10?1 to 10?9) and 50 μl from each dilution was plated onto blood agar and incubated overnight in air flow at 37°C for CFU counts. One hundred microliters from each of these dilutions was transferred to sterile cotton-tipped swabs (in triplicate) and placed in 5 ml Oxoid indication broth incubated for 2 h. Fifty microliters was taken from each culture and CFU counts were performed. A further 1 ml was removed and processed as explained below for PCR analysis. PCR. The commercial PCR used was the BD GeneOhm MRSA assay (Becton Dickinson Franklin PMCH Lakes NJ). After 2 h of incubation at 37°C each enrichment broth was vortexed for 30 s. A 1-ml aliquot was TBC-11251 centrifuged at 13 0 × for 5 min at room temperature supernatants were discarded and the pellet was resuspended in 1 ml of BD GeneOhm sample buffer. Each suspension was transferred to a BD GeneOhm lysis tube for DNA extraction according to the manufacturer’s.