RESUMEN
The identification and control of methicillin-resistant Staphylococcus aureus (MRSA) is of primary concern in intensive care units (ICUs) worldwide. The introduction and circulation of particular strains is best studied by genomic procedures and random amplified polymorphic DNA (RAPD) is well suited for this task. In this study 14 isolates of MRSA, obtained over an 8 month period from the blood cultures of 12 patients in an ICU at our hospital, were typed by RAPD method using seven primers. Three separate groups were distinguished and clustering of certain types in time and space was noted. These results suggest that although different strains of MRSA were involved in this outbreak, cross-infection with individual types occurred. RAPD fingerprinting is a relatively simple method that allows epidemiologic investigation of MRSA outbreaks in hospital infection.
Asunto(s)
Unidades de Cuidados Intensivos , Resistencia a la Meticilina , Técnica del ADN Polimorfo Amplificado Aleatorio , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificación , Técnicas de Tipificación Bacteriana , Humanos , Control de Infecciones , Reacción en Cadena de la Polimerasa , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genéticaRESUMEN
A single Polymerase Chain Reaction (PCR) within the rpoV gene was developed to rapidly distinguish mycobacteria isolated from clinical specimens. The species identifications of Mycobacterium avium complex (MAC) and Mycobacterium tuberculosis were congruent with standard typing techniques. The analysis was targeted toward the identification of species-specific markers for the clinically relevant M. tuberculosis and M. avium. In addition, HaeIII digestion of the amplification products yielded isolates-specific bands.
Asunto(s)
Complejo Mycobacterium avium/clasificación , Infección por Mycobacterium avium-intracellulare/diagnóstico , Mycobacterium tuberculosis/clasificación , Tuberculosis/diagnóstico , Cartilla de ADN/química , Enzimas de Restricción del ADN/química , ADN Bacteriano/química , Electroforesis en Gel de Poliacrilamida , Humanos , Complejo Mycobacterium avium/genética , Mycobacterium tuberculosis/genética , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Factor sigma/química , Especificidad de la EspecieRESUMEN
Mycobacteria Growth Indicator Tube (MGIT) is a recently introduced rapid growth detection method which uses an oxygen quenched fluorescent indicator. The present study evaluated the ability of this new method to determine the drug susceptibility of Mycobacterium avium complex (MAC). Thirty strains recovered from patients with AIDS were tested for susceptibility to clarithromycin, rifabutin, ciprofloxacin, azithromycin and amikacin using MGIT. Results were compared to susceptibilities determined by the agar dilution method. The results obtained showed a 100% correlation between MGIT and the agar dilution method for rifabutin and clarithromycin. There was a 100% correlation between the two methods for azithromycin against 27 strains. MGIT was well correlated with the agar dilution method for detecting resistance to clarithromycin, rifabutin and azithromycin in 4 days, but the correlation was poor when susceptibilities to ciprofloxacin and amikacin were determined. This rapid method is non-radiometric, noninvasive and does not require any special instruments.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/microbiología , Antibacterianos/farmacología , Antiinfecciosos/farmacología , Mycobacterium avium/efectos de los fármacos , Agar , Amicacina/farmacología , Azitromicina/farmacología , Ciprofloxacina/farmacología , Claritromicina/farmacología , Fluoroinmunoensayo , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium avium/genética , Hibridación de Ácido Nucleico , Rifabutina/farmacologíaRESUMEN
Different epidemiological markers were used to characterize 2 Staphylococcus epidermidis and 8 Staphylococcus aureus strains isolated from patients with severe infections. We compared random amplified polymorphic DNA (RAPD) fingerprints, biotypes, antibiotic assays, plasmid profiles and chromosomal DNA restriction endonuclease analysis (REA). Data analysis based on numerical taxonomy methods indicates that RAPD and REA give similar results allowing a good discrimination of the two species and of each isolate. The RAPD method is easier and faster than REA, but the reproducibility of RAPD fingerprints obtained in independent experiments can be problematic. We have found simple technical devices to improve the reproducibility of the RAPD procedure which is therefore a very useful tool in epidemiology for identification and characterization of Staphylococcus spp.