RESUMEN
Providencia stuartii has emerged as an important nosocomial pathogen. We describe an outbreak due to a multidrug-resistant strain over a 4-month period in a critical care unit in Athens. Molecular typing revealed each of the isolates to be clonally related with coresistance to cephalosporins, carbapenems, aminoglycosides, and quinolones. Each isolate contained a 220-kb multi-replicon (IncA/C and IncR) conjugative plasmid encoding TEM-1, SHV-5, VEB-1, and VIM-1 ß-lactamases and the 16S rDNA methylase RmtB. Antimicrobial therapy was unsuccessful in 3 of 6 cases, and resistance was readily transmissible to susceptible strains of Escherichia coli by transformation and conjugation. This highlights the clinical importance of P. stuartii and its ability to disseminate critical resistance determinants to other bacterial pathogens.
Asunto(s)
Proteínas Bacterianas/genética , Infección Hospitalaria/epidemiología , Brotes de Enfermedades , Farmacorresistencia Bacteriana Múltiple/genética , Infecciones por Enterobacteriaceae/epidemiología , Providencia/genética , Adulto , Anciano , Aminoglicósidos/farmacología , Antibacterianos/farmacología , Carbapenémicos/farmacología , Cefalosporinas/farmacología , Células Clonales , Conjugación Genética , Infección Hospitalaria/tratamiento farmacológico , Infección Hospitalaria/microbiología , Infección Hospitalaria/mortalidad , Infecciones por Enterobacteriaceae/tratamiento farmacológico , Infecciones por Enterobacteriaceae/microbiología , Infecciones por Enterobacteriaceae/mortalidad , Femenino , Expresión Génica , Transferencia de Gen Horizontal , Grecia/epidemiología , Humanos , Masculino , Metiltransferasas/genética , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Plásmidos/química , Plásmidos/metabolismo , Providencia/efectos de los fármacos , Providencia/enzimología , Providencia/aislamiento & purificación , Quinolonas/farmacología , Replicón , Análisis de Supervivencia , beta-Lactamasas/genéticaRESUMEN
A comparison of a matrix-assisted laser desorption ionization-time of flight mass spectrometric (MALDI-TOF MS) meropenem hydrolysis assay with the Carba NP test showed that both methods exhibited low sensitivity (approximately 76%), mainly due to the false-negative results obtained with OXA-48-type producers. The addition of NH4HCO3 to the reaction buffer for the MALDI-TOF MS assay dramatically improved its sensitivity (98%). Automatic interpretation of the MALDI-TOF MS assay, using the MBT STAR-BL software, generally agreed with the results obtained after manual analysis. For the Carba NP test, spectrophotometric analysis found six additional carbapenemase producers.
