Publications by authors named "Ryan R McDonald"

Auxin and cytokinin partially restore (formerly ) gametophores that have developed in the dark to a form more typical of those grown in light. Auxin synthesis and/or transport in gametophores decrease with time spent in the dark. Auxin synthesis resumes in the apices of dark-grown gametophores upon their return to the light.

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The recent emergence of a severe respiratory disease caused by enterovirus D68 prompted investigation into whether Canadian hospital and provincial laboratories can detect this virus using commercial and laboratory-developed assays. This study demonstrated analytical sensitivity differences between commercial and laboratory-developed assays for the detection of enterovirus D68.

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Here, we announce the draft sequence of a representative methicillin-susceptible Staphylococcus aureus (MSSA) isolate (06BA18369) whose strain type (spa type t311) was commonly isolated from skin and soft tissue coinfections with Streptococcus pyogenes. This strain sequence provides insight into a highly successful community-associated MSSA strain type.

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We report the draft sequence of Streptococcus pyogenes 06BA18369 (emm type 41.2, sequence type 579 [ST579]), isolated from a skin and soft tissue infection (SSTI) mixed with Staphylococcus aureus. This genome provides insight into the genetic composition of S.

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Despite reports of high colonization rates of ST398 livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) among pigs and pig farmers, the incidence of LA-MRSA infection in the general population in Canada appears to be rare in comparison to that in some European countries. In this study, the complete genome sequence of a Canadian representative LA-MRSA isolate (08BA02176) from a human postoperative surgical site infection was acquired and compared to the sequenced genome of an LA-MRSA isolate (S0385) from Europe to identify genetic traits that may explain differences in the success of these particular strains in some locales.

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Antimicrobial resistance is a growing concern especially in many remote northern communities of Canada where antimicrobials are liberally used. In this study, 1418 Escherichia coli urinary tract infection (UTI) isolates, obtained over a 2.5-year period (October 2005-March 2008), from 3 remote northern sites in Saskatchewan, Canada, were identified.

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Surveillance of Staphylococcus aureus infections in 3 northern remote communities of Saskatchewan was undertaken. Rates of methicillin-resistant infections were extremely high (146-482/10,000 population), and most (98.2%) were caused by USA400 strains.

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Molecular diagnostic tools capable of identifying Shiga toxin-specific genetic determinants in stool specimens permit an unbiased approach to detect Shiga toxin-producing Escherichia coli (STEC) in clinical samples and can indicate when culture-based isolation methods are required. It is increasingly recognized that clinically relevant STEC are not limited to the singular O157 serotypes, and therefore diagnostic assays targeting toxin-encoding determinants must be able to account for any genetic variation that exists between serotypes. In this study conventional PCR and four real-time PCR assays (HybProbe, TaqMan, SYBR Green, and LUX) targeting the stx1 and stx2 Shiga toxin coding sequences were used to identify STEC in enriched stool samples (n = 36) and a panel of O157 and non-O157 strains (n = 64).

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Rates of colonization with livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) sequence type 398 have been high for pigs and pig farmers in Canada, but prevalence rates for the general human population are unknown. In this study, 5 LA-MRSA isolates, 4 of which were obtained from skin and soft tissue infections, were identified from 3,687 tested MRSA isolates from persons in Manitoba and Saskatchewan, Canada. Further molecular characterization determined that these isolates all contained staphylococcal cassette chromosome (SCC) mecV, were negative for Panton-Valentine leukocidin, and were closely related by macrorestriction analysis with the restriction enzyme Cfr91.

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Background: Molecular diagnosis of Norovirus infection can be a complex multistep process, which requires significant user intervention and expertise, and is not amenable to automation without extensive validation and optimization.

Objectives: To develop a real-time multiplexed RT-PCR assay with automated sample preparation that requires only a single-step and a single-tube for reverse transcription, amplification, and detection while exceeding the sensitivity of conventional PCR for broad-spectrum Norovirus detection.

Study Design: Limit of detection was assessed against dilutions of clinical specimens.

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Community-associated methicillin-resistant Staphylococcus aureus harboring Panton-Valentine leukocidin (PVL) genes is an emerging pathogen. A novel real-time PCR assay for identification of MRSA isolates containing PVL was developed. The PVL assay was used in a triplex format allowing simultaneous amplification of mecA, nuc, and PVL genes in 614 clinical isolates.

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Quick and accurate genotyping of hepatitis C virus (HCV) is becoming increasingly important for clinical management of chronic infection and as an epidemiological marker. Furthermore, the incidence of HCV infection with mixed genotypes has clinical significance that is not addressed by most genotyping methods. We have developed a fluorescence-based genotyping assay called primer-specific extension analysis (PSEA) for the most prevalent HCV genotypes and have demonstrated the capacity of PSEA-HCV for detecting mixed-genotype HCV infections.

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Homogenous fluorescence PCR assays offer distinct advantages for qualitative testing and are gaining immense popularity in fields like diagnostic microbiology. To meet the demand of high-volume laboratories, we developed a protocol for qualitative multiplex 5' nuclease assays using post-only PCR analysis. This novel approach overcomes throughput problems encountered with the established methods for TaqMan detection on the ABI PRISM 7700 Sequence Detection system and permits off-site TaqMan PCR, which can be analyzed several days after the reactions are completed.

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