RESUMO
A triplex-PCR assay was developed and evaluated for rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) recovered from various biological samples of pig. Three sets of primers were designed to target mecA, 16S rRNA and nuc genes of MRSA. The specific amplification generated three bands on agarose gel, with sizes 280 bp for mecA, 654 bp for 16S rRNA and 481 bp for nuc, respectively. A potential advantage of the PCR assay is its sensitivity with a detection limit of 102 CFU per ml of bacteria. In all, 79 MRSA isolates recovered from various samples of pigs were subjected to the amplification by the triplex-PCR assay and all the isolates yielded three bands corresponding to the three genes under this study. No false-positive amplification was observed, indicating the high specificity of the developed triplex-PCR assay. This assay will be a useful and powerful method for differentiation of MRSA from methicillin-sensitive S. aureus, coagulase-negative methicillin-resistant staphylococci and coagulase-negative methicillin-sensitive staphylococci.
Assuntos
Resistência a Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Reação em Cadeia da Polimerase Multiplex/métodos , Infecções Estafilocócicas/veterinária , Animais , Proteínas de Bactérias/genética , Primers do DNA/genética , Humanos , Limite de Detecção , Meticilina/farmacologia , Staphylococcus aureus Resistente à Meticilina/genética , Nuclease do Micrococo/genética , Proteínas de Ligação às Penicilinas/genética , RNA Ribossômico 16S/genética , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , SuínosRESUMO
The multifarious nature of biodiversity is considered in relation to difficulties of definite determination and managerial mandates for monitoring. At a micro scale there is some convergence with the concept of community, but the linkage is largely lost in the spectra of temporal scope, spatial scales, successional seres, and taxonomic trajectories. Practicality points to selecting suitable suites of indicators as surrogates for particular purposes. Domains of partial ordering on multiple indicators constitute comparable collectives, whereas different domains require recognition of special situations. Theoretical treatise and practical process can proceed in parallel, with dialogue and cross-fertilization serving to invigorate and inspire; whereas compulsive concern for completeness and consistency can be counter-productive as well as unduly expensive. Inability to completely capture all aspects of biodiversity in one full formulation is interesting and integral to issues of biocomplexity.
Assuntos
Biodiversidade , Ecologia , Animais , Classificação , Especificidade da EspécieRESUMO
This article develops a computationally and analytically convenient form of the profile likelihood method for obtaining one-sided confidence limits on scalar-valued functions phi = phi(psi) of the parameters psi in a multiparameter statistical model. We refer to this formulation as the likelihood contour method (LCM). In general, the LCM procedure requires iterative solution of a system of nonlinear equations, and good starting values are critical because the equations have at least two solutions corresponding to the upper and lower confidence limits. We replace the LCM equations by the lowest order terms in their asymptotic expansions. The resulting equations can be solved explicitly and have exactly two solutions that are used as starting values for obtaining the respective confidence limits from the LCM equations. This article also addresses the problem of obtaining upper confidence limits for the risk function in a dose-response model in which responses are normally distributed. Because of normality, considerable analytic simplification is possible and solution of the LCM equations reduces to an easy one-dimensional root-finding problem. Simulation is used to study the small-sample coverage of the resulting confidence limits.
