g Carbapenem-resistant Pseudomonas aeruginosa has become a serious health threat worldwide due to the limited options available for its treatment. Understanding its epidemiology contributes to the control of antibiotic resistance. The aim of this study was to describe the clinical and molecular characteristics of infections caused by carbapenem-resistant P. aeruginosa isolates in five tertiary-care hospitals in Medellín, Colombia. A cross-sectional study was conducted in five tertiary-care hospitals from June 2012 to March 2014. All hospitalized patients infected by carbapenem-resistant P. aeruginosa were included. Clinical information was obtained from medical records. Molecular analyses included PCR for detection of bla VIM , bla IMP , bla NDM , bla OXA-48 , and bla KPC genes plus pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for molecular typing. A total of 235 patients were enrolled: 91.1% of them were adults (n ‫؍‬ 214), 88.1% (n ‫؍‬ 207) had prior antibiotic use, and 14.9% (n ‫؍‬ 35) had urinary tract infections. The bla VIM-2 and bla KPC-2 genes were detected in 13.6% (n ‫؍‬ 32) and 11.5% (n ‫؍‬ 27), respectively, of all isolates. Two isolates harbored both genes simultaneously. For KPC-producing isolates, PFGE revealed closely related strains within each hospital, and sequence types (STs) ST362 and ST235 and two new STs were found by MLST. With PFGE, VIM-producing isolates appeared highly diverse, and MLST revealed ST111 in four hospitals and five new STs. These results show that KPC-producing P. aeruginosa is currently disseminating rapidly and occurring at a frequency similar to that of VIM-producing P. aeruginosa isolates (approximately 1:1 ratio) in Medellín, Colombia. Diverse genetic backgrounds among resistant strains suggest an excessive antibiotic pressure resulting in the selection of resistant strains.

No abstract

Cómo citar este artículo: Esparza GF, et al. Aspectos microbiológicos en el diagnóstico de infecciones del tracto urinario. Infectio. 2015. http://dx.

ResumenLos métodos fenotípicos empleados para la identificación de microorganismos dependen de procesos metabólicos que requieren de tiempos de incubación mínimos para alcanzar resultados confiables. La espectrometría de masas MALDI-TOF (desorción/ionización láser asistida por una matriz con detección de masas por tiempo de vuelo) se ha instaurado como una metodología relevante para la identificación de microorganismos mediante el análisis de proteínas, a través de la creación de un espectro de masas específico de género y especie. En esta revisión, se presenta MALDI-TOF MS como una tecnología precisa para la identificación de bacterias, levaduras, mohos, en incluso de virus, que además, permite la reducción del tiempo para obtener un resultado de identificación, que puede impactar los costos de atención y duración de la estancia hospitalaria. La identificación de microorganismos directamente de muestras biológicas y la detección de mecanismos de resistencia a antimicrobianos, prometen un mayor impacto clínico y epidemiológico con el desarrollo e implementación de esta tecnología en los laboratorios de microbiología clínica.Palabras clave: MALDI-TOF MS, espectrometría de masas, diagnóstico microbiológico, identificación de patógenos, proteómica, infección del torrente sanguíneo, infección del tracto urinario. MALDI-TOF mass spectrometry in clinical microbiology laboratories. AbstractPhenotypic methods used for the identification of microorganisms depend on metabolic processes that require minimum incubation times to achieve reliable results. For this reason, MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionization Mass Spectrometry) has been established as a relevant methodology for the identification of microorganisms using analysis of proteins, through the creation of a mass spectrum specific for genus and species. In the present review, MALDI-TOF MS is presented as an accurate technology for identifying bacteria, yeasts, molds and viruses; Its use allows reduction of the time to obtain an identification result, which may impact the costs of care and length of hospital stay. The identification of microorganisms directly from biological samples and the detection of mechanisms of antimicrobial resistance, promise an additional clinical and epidemiological impact with the development and implementation of this technology in clinical microbiology laboratories.Keywords: MALDI-TOF MS, mass spectrometry, microbiological diagnostic, pathogen identification, proteomics, blood stream infection, urinary tract infection. REVISIÓN IntroducciónLa identificación de microorganismos se ha realizado tradicionalmente por métodos basados en tinciones que permiten la clasificación de la morfología microscópica con el fin de apoyar decisiones diagnósticas y terapéuticas tempranas; así como en pruebas in vitro basadas en reacciones bioquímicas utilizadas por sistemas manuales o automatizados, que integran pruebas con diferentes sustratos, incrementando la rapidez y simplicidad de la identificación. Sin embargo, estos métodos fenotí...