Factores de riesgo de las infecciones nosocomiales en pacientes que reciben oxigenación por membrana extracorpórea / Risk factors for nosocomial infections in patients receiving extracorporeal membrane oxygenation supportive therapy

Antecedentes y objetivo: El objetivo de este estudio fue analizar los factores de riesgo de la infección nosocomial (IN) en pacientes que reciben soporte de extracorporeal membrane oxygenation (ECMO, «oxigenación por membrana extracorpórea»). Pacientes y métodos: Se recolectaron los datos clínicos de las IN de los pacientes que recibieron tratamiento de soporte ECMO, analizándose retrospectivamente. Resultados: Entre los 75 pacientes con ECMO, se encontró que 20 habían desarrollado IN (tasa de infección del 26,7%), aislándose un total de 58 patógenos, incluyendo 43 cepas de bacterias gramnegativas (74,1%) y 15 cepas de bacterias grampositivas (25,9%). Las cepas resistentes a múltiples fármacos se hallaban altamente concentradas, componiéndose principalmente de Acinetobacter baumannii, Pseudomonas aeruginosa y estafilococos coagulasa negativos. La incidencia de IN se relacionó con la duración del tratamiento de soporte ECMO y la estancia hospitalaria total, siendo las diferencias estadísticamente significativas (p<0,05). Un período prolongado de soporte ECMO ampliaba la estancia hospitalaria, aunque no incrementaba la tasa de mortalidad. Sin embargo, la elevación del nivel de ácido láctico incrementaba la tasa de mortalidad en esta población de estudio. Conclusiones: Las IN secundarias asociadas a ECMO guardaron una correlación considerable con la duración de la estancia hospitalaria y la duración del soporte ECMO. Por tanto, para reducir la incidencia de las IN asociadas a ECMO, deberán aplicarse estrategias en aras de reducir la duración del tratamiento de soporte ECMO y evitar la hospitalización prolongada, cuando ello sea posible (AU)

Background and objective: The aim of this study was to analyze risk factors for nosocomial infection (NI) in patients receiving extracorporeal membrane oxygenation (ECMO) support. Patients and methods: Clinical NI data were collected from patients who received ECMO support therapy, and analyzed retrospectively. Results: Among 75 ECMO patients, 20 were found to have developed NI (infection rate 26.7%); a total of 58 pathogens were isolated, including 43 strains of gram-negative bacteria (74.1%) and 15 strains of gram-positive bacteria (25.9%). Multi-drug resistant strains were highly concentrated and were mainly shown to be Acinetobacter baumannii, Pseudomonas aeruginosa, and coagulase-negative staphylococci. Incidence of NI was related to the duration of ECMO support therapy and the total length of hospital stay, and the differences were statistically significant (P<.05). A prolonged period of ECMO support extended the hospital stay, but it did not increase the mortality rate. However, an elevated level of lactic acid increased the mortality rate in this study population. Conclusions: ECMO-associated secondary NIs correlated significantly with the length of hospital stay and with the duration of ECMO support. Therefore, to reduce the incidence of ECMO-associated NIs, preventive strategies that aim to shorten the duration of ECMO support therapy and avoid lengthy hospitalization should be applied, wherever possible (AU)

Risk factors for nosocomial infections in patients receiving extracorporeal membrane oxygenation supportive therapy. / Factores de riesgo de las infecciones nosocomiales en pacientes que reciben oxigenación por membrana extracorpórea.

BACKGROUND AND OBJECTIVE: The aim of this study was to analyze risk factors for nosocomial infection (NI) in patients receiving extracorporeal membrane oxygenation (ECMO) support. PATIENTS AND METHODS: Clinical NI data were collected from patients who received ECMO support therapy, and analyzed retrospectively. RESULTS: Among 75 ECMO patients, 20 were found to have developed NI (infection rate 26.7%); a total of 58 pathogens were isolated, including 43 strains of gram-negative bacteria (74.1%) and 15 strains of gram-positive bacteria (25.9%). Multi-drug resistant strains were highly concentrated and were mainly shown to be Acinetobacter baumannii, Pseudomonas aeruginosa, and coagulase-negative staphylococci. Incidence of NI was related to the duration of ECMO support therapy and the total length of hospital stay, and the differences were statistically significant (P<.05). A prolonged period of ECMO support extended the hospital stay, but it did not increase the mortality rate. However, an elevated level of lactic acid increased the mortality rate in this study population. CONCLUSIONS: ECMO-associated secondary NIs correlated significantly with the length of hospital stay and with the duration of ECMO support. Therefore, to reduce the incidence of ECMO-associated NIs, preventive strategies that aim to shorten the duration of ECMO support therapy and avoid lengthy hospitalization should be applied, wherever possible.

Colorimetric detection of genetically modified organisms based on exonuclease III-assisted target recycling and hemin/G-quadruplex DNAzyme amplification.

An isothermal colorimetric method is described for amplified detection of the CaMV 35S promoter sequence in genetically modified organism (GMO). It is based on (a) target DNA-triggered unlabeled molecular beacon (UMB) termini binding, and (b) exonuclease III (Exo III)-assisted target recycling, and (c) hemin/G-quadruplex (DNAzyme) based signal amplification. The specific binding of target to the G-quadruplex sequence-locked UMB triggers the digestion of Exo III. This, in turn, releases an active G-quadruplex segment and target DNA for successive hybridization and cleavage. The Exo III impellent recycling of targets produces numerous G-quadruplex sequences. These further associate with hemin to form DNAzymes and hence will catalyze H2O2-mediated oxidation of the chromogenic enzyme substrate ABTS2- causing the formation of a green colored product. This finding enables a sensitive colorimetric determination of GMO DNA (at an analytical wavelength of 420 nm) at concentrations as low as 0.23 nM. By taking advantage of isothermal incubation, this method does not require sophisticated equipment or complicated syntheses. Analyses can be performed within 90 min. The method also discriminates single base mismatches. In our perception, it has a wide scope in that it may be applied to the detection of many other GMOs. Graphical abstract An isothermal and sensitive colorimetric method is described for amplified detection of CaMV 35S promoter sequence in genetically modified organism (GMO). It is based on target DNA-triggered molecular beacon (UMB) termini-binding and exonuclease III assisted target recycling, and on hemin/G-quadruplex (DNAzyme) signal amplification.

Utility of multiple-locus variant-repeat analysis method for the outbreak of the Pseudomonas aeruginosa isolates.

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) predominated in hospitals. METHODS: In order to determine the source of the outbreak and take effective measures to prevent the spread, we tested their relationships between the strains. 97 P. aeruginosa samples were analyzed by multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) method. In order to identify a minimal subset that could provide high discrimination, we evaluated the ability of various VNTR sets. RESULTS: The result showed all of the 11 loci displayed high discrimination, and the lowest loci was ms223 (h = 0.59). The 97 strains were all discriminated (HGDI = 1.0000). The top 7-locus set produced a HGDI value of 1.0000, which was the same as the 11-locus set. The 4-locus set had a HGDI value of 0.9972 with a clustering rate of 11.3%. The strains were divided into four groups based on the phylogenetic clustering and genotypic characteristics. There were obvious differences among the four groups regarding the drug-resistance patterns of Imipenem, Ciprofloxacin, Ceftazidime, Levofloxacin, Meropenem, Piperacillin, Cefepime, Aztreonam (p < 0.05). CONCLUSIONS: In conclusion, the transmission of the strains was not found in this study. The 7-locus set yielded a high discrimination, while for an easier and more robust MLVA scheme, the number of markers can be reduced to 4 loci of ms212, ms211, ms213, and ms142. These four strains from four inpatients in the same ward displayed the same drug resistance spectrum. The MLVA genotype results showed the four strains had the same gene structures. The four patients were from the same treatment group. They showed the IMP-1 allele and belonged to the aac (6')-I type, and there was a deletion of the OprD2 gene in four strains, supporting the MLVA results in suggesting that they are similar.