Análisis epidemiológico de bacteriemias asociadas a catéter en una terapia intensiva médico-quirúrgica / Epidemiological analysis of catheter-related bloodstream infections in medical-surgical intensive care units

Resumen Se realizó un estudio observacional retrospectivo analítico que evaluó la epidemiología de las bacteriemias asociadas a catéter central (BAC) en 773 adultos internados en la unidad de cuidados intensivos (UCI) del Hospital Alemán de Buenos Aires entre diciembre de 2018 y junio de 2020. Durante el pe riodo de estudio, la incidencia fue 8.7 eventos cada 1000 días catéter. El desarrollo de BAC se asoció con mala evolución clínica, que fue puesta en evidencia por una duración de la internación en UCI significativamente mayor que la de los pacientes sin BAC (mediana: 21.5 días vs. 4 días, p < 0.001). La mortalidad también fue mayor, pero sin significancia estadística (24% vs. 20%, OR 1.26 [0.61-2.63]). Los microorganismos más frecuentemente aislados fueron bacterias Gram positivas (73%) y, entre ellas, Staphylococcus epidermidis fue la más frecuente (40%). De los 47 aislamientos de microorganismos relevados, 8 (17%) fueron gérmenes multirresistentes. El análisis multivariado identificó el tiempo de permanencia del catéter como factor de riesgo para desarrollar BAC (OR 1.10 [1.05 - 1.15], p < 0.001). En dicho análisis, una mayor tasa de BAC no fue influida por el sitio anatómico de inserción del catéter, el servicio donde se realizó el procedimiento (UCI o quirófano/servicio de emergencias), la experiencia previa del médico en el procedimiento, ni el uso de ultrasonido para guiar la cateterización. Con cluimos que las BAC son una complicación frecuente en nuestro servicio con consecuencias clínicas relevantes. Conocer la epidemiología y la problemática de cada servicio permite programar intervenciones dirigidas a corregir problemas concretos de salud pública.

Abstract A retrospective-observational analytical study was carried out to evaluate the epidemiology of catheter-related bloodstream infections (CRBSI) in 773 adult patients hospitalized in the inten sive care unit (ICU) of the Hospital Alemán of Buenos Aires, Argentina, between 1 December 2018 and 30 June 2020. During the study period, the incidence of CRBSI was 8.7 cases per 1000 catheter days. The occurrence of CRBSI was found associated with a poor clinical evolution, as evidenced by a stay in the ICU significantly longer than the stay of patients without CRBSI (median: 21.5 days vs. 4 days, p < 0.001). CRBSI-associated mortality was not statistically higher (24% vs. 20%, OR 1.26 [0.61-2.63]). Gram-positive bacteria were the most frequently identified microorganisms (73%), being Staphylococcus epidermidis the most frequent (40%). Of the 47 isolates of microorganisms surveyed, 8 (17%) were multi-resistant germs. The permanence time of the catheter was identified as a risk factor for developing CRBSI (OR 1.10 [1.05 - 1.15], p < 0.001) in a multivariate analysis. In this analysis, the risk of infection was not influenced by the anatomical site of insertion of the catheter, the ward where the procedure was performed (ICU vs. operating room/external ward), the skill of the medical practitioner, or the use of ultrasound to guide vascular accesses. We conclude that CRBSIs are a frequent complication in our department with relevant clinical consequences. Knowing the epidemiology and the problems of each service allows programming interventions aimed to correct specific public health problems.

Biological variability in clinical isolates of Trichomonas vaginalis

Eighteen clinical isolates of Trichomonas vaginalis were obtained from women who attended health centers of the Goverment of Madrid. A total of 1,848 vaginal specimens recovered during the gynaecological examination were seeded in culture tubes containing liquid Diamond medium. Pathogenicity to mice was determined after intraperitoneal inoculation of mice by quantification of mortality and gross damage to abdominal organs. As could be expected, a broad variability was obtained, being some of the isolates more virulent than the reference strain. Regarding to metronidazole susceptibility, none resistant isolate was found but different degrees of susceptibility were determined

Relationship between biological behaviour and randomly amplified polymorphic DNA profiles of Trypanosoma cruzi strains

Once known some biological characteristics of six Trypanosoma cruzi strains, randomly amplified polymorphic DNA (RAPD) analysis was made. Cluster analysis by UPGMA (unweighted pair group method analysis) was then applied both to biological parameters and RAPD profiles. Inspection of the UPGMA phenograms indicates identical clusters, so supporting that usefulness of biological parameters to characterization of T. cruzi strains still remains

Biological characterization of Trypanosoma cruzi strains

Biological parameters of five Trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. The parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. Differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. Regarding to pharmacological assays, Y strain was the most sensitive to the three assayed compounds. These data demonstrate the heterogeneity of natural populations of T. cruzi, the only responsible of infection in humans