Clinical characteristics and outcome of bacteraemia caused by Enterobacter cloacae and Klebsiella aerogenes: more similarities than differences.

OBJECTIVES: The genus Enterobacter is a common cause of nosocomial infections. Historically, the most frequent Enterobacter species were those of Enterobacter cloacae complex and Enterobacter aerogenes. In 2019, E. aerogenes was re-classified as Klebsiella aerogenes owing to its higher genotypic similarity with the genus Klebsiella. Our objective was to characterise and compare the clinical profiles of bacteraemia caused by E. cloacae and K. aerogenes. METHODS: This 3-year multicentre, prospective cohort study enrolled consecutive patients with bacteraemia by E. cloacae or K. aerogenes. Baseline characteristics, bacteraemia features (source, severity, treatment), antibiotic susceptibility, resistance mechanisms and mortality were analysed. RESULTS: The study included 285 patients with bacteraemia [196 (68.8%) E. cloacae and 89 (31.2%) K. aerogenes]. The groups showed no differences in age, sex, previous use of invasive devices, place of acquisition, sources or severity at onset. The Charlson score was higher among patients with E. cloacae bacteraemia [2 (1-4) vs. 1 (0.5-3); P = 0.018], and previous antibiotic therapy was more common in patients with K. aerogenes bacteraemia (57.3% vs. 41.3%; P = 0.01). Mortality was 19.4% for E. cloacae and 20.2% for K. aerogenes (P = 0.869). Antibiotic susceptibility was similar for both species, and the incidence of multidrug resistance or ESBL production was low (6% and 5.3%, respectively), with no differences between species. CONCLUSION: Bacteraemias caused by E. cloacae and K. aerogenes share similar patient profiles, presentation and prognosis. Patients with E. cloacae bacteraemia had more co-morbidities and those with K. aerogenes bacteraemia had received more antibiotics.

HCV microelimination strategies: An interventional study in diagnosed patients without access to the system.

Hepatitis C virus (HCV) one-step diagnosis improves recovery in patients with active infection. However, patients with previous anti-HCV+ may be excluded. We aimed to identify and retrieve non-referred or lost-to-follow-up HCV-infected patients. All anti-HCV+ patients seen in our hospital between 2013 and 2018 were included. In the first phase, we identified anti-HCV+ patients who were not referred to the Gastroenterology Unit (GU) or lost-to-follow-up. In the second phase, recovered patients were invited for a one-step visit for liver evaluation. A total of 1330 anti-HCV+ patients were included: 21.7% had not been referred to GU, and 23.1% were lost-to-follow-up. In the second phase, 49.6% of patients were contacted, and 92.8% attended a medical consultation: 62.7% had active infection, 92.2% were treated, and 86.5% achieved SVR (ITT). We concluded that screening microbiological data and referring unidentified patients with active HCV infection directly to specialists is an effective tool in achieving HCV microelimination.

A prospective, multicenter case control study of risk factors for acquisition and mortality in Enterobacter species bacteremia.

BACKGROUND: Enterobacter is among the main etiologies of hospital-acquired infections. This study aims to identify the risk factors of acquisition and attributable mortality of Enterobacter bacteremia. METHODS: Observational, case-control study for risk factors and prospective cohort for outcomes of consecutive cases with Enterobacter bacteremia. This study was conducted in five hospitals in Spain over a three-year period. Matched controls were patients with negative blood cultures and same sex, age, and hospitalization area. RESULTS: The study included 285 cases and 570 controls. E. cloacae was isolated in 198(68.8%) cases and E. aerogenes in 89(31.2%). Invasive procedures (hemodialysis, nasogastric tube, mechanical ventilation, surgical drainage tube) and previous antibiotics or corticosteroids were independently associated with Enterobacter bacteremia. Its attributable mortality was 7.8%(CI95%2.7-13.4%), being dissimilar according to a McCabe index: non-fatal=3.2%, ultimately fatal=12.9% and rapidly fatal=0.12%. Enterobacter bacteremia remained an independent risk factor for mortality among cases with severe sepsis or septic shock (OR 5.75 [CI95%2.57-12.87], p<0.001), with an attributable mortality of 40.3%(CI95%25.7-53.3). Empiric therapy or antibiotic resistances were not related to the outcome among patients with bacteremia. CONCLUSIONS: Invasive procedures, previous antibiotics and corticosteroids predispose to acquire Enterobacter bacteremia. This entity increases mortality among fragile patients and those with severe infections. Antibiotic resistances did not affect the outcome.

First report of NDM-1-producing clinical isolate of Leclercia adecarboxylata in Spain.

We describe the case of NDM-1-producing Leclercia adecarboxylata recovered from the clinical sample of a patient hospitalized for a trauma-related injury to his foot. The isolate was resistant to all beta-lactams, quinolones, trimetroprim-sulfametoxazol, gentamicin and tobramicyn. The blaNDM-1 gene was located in a conjugative plasmid that also contained the blaSHV-12 gene and was preceded by a disrupted insertion sequence of ISAba125. The plasmid belongs to the incompatibility group X3, which is known to be an important vector for NDM-1 dissemination in China. This is the first reported case of NDM-1L. adecarboxylata in our country and evidences that species of uncertain clinical relevance can act as hidden sources of clinically important resistance determinants.

Aplicación de la espectrometría de masas en la identificación de bacterias / Application of mass spectrometry to bacterial identification

Una identificación correcta y rápida de las bacterias es esencial para un diagnóstico y un tratamiento adecuado de los pacientes con infecciones. Hasta hace pocos años se utilizaban pruebas bioquímicas, colorimétricas o incluso de sensibilidad antibiótica para la identificación a niveles de género y especie. Las principales limitaciones de estos métodos son el tiempo necesario para su realización y la dificultad para diferenciar microorganismos poco reactivos, muy parecidos entre ellos o de difícil crecimiento. Desde la introducción en el laboratorio de la espectrometría de masas (EM) con el uso de MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight), muchos de estos problemas se han solventado. Para poder sacar el máximo rendimiento a esta tecnología se han de conocer sus puntos fuertes y sus limitaciones. No todos los microorganismos se identifican con la misma facilidad o fiabilidad mediante MALDI-TOF y es obligación del microbiólogo saber cómo interpretar los resultados que de este se obtienen y las alternativas disponibles para lograr identificar los microorganismos que generan más problemas. Este trabajo pretende hacer una recopilación de la información disponible sobre la correcta identificación de las principales bacterias patógenas humanas mediante el uso de la EM MALDI-TOF, centrándose en gramnegativos, grampositivos y microorganismos anaerobios. Las condiciones del cultivo, la preparación de la extensión con el método de extracción idóneo y, sobre todo, el uso de una correcta y actualizada base de datos son los principales factores que hay que tener en cuenta para la identificación fiable de cualquier bacteria

Correct and rapid identification of bacteria is essential for the correct diagnosis and treatment of infected patients. Until a few years ago, biochemical, colorimetric or even antibiotic sensitivity tests were used to identify genera and species. The main limitations of these methods were the time needed for their performance and the difficulty of distinguishing between microorganisms that were little reactive, highly similar, or difficult to culture. Many of these problems have been solved by the introduction of mass spectrometry (MS) in the laboratory with the use of MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight). Knowledge of the strengths and weaknesses of this technology is essential to be able to take maximum advantage of this technique. Not all microorganisms can be identified with the same ease and reliability by MALDI-TOF and microbiologists need to know how to interpret the results obtained with this technique and the available alternatives in order to identify the microorganisms causing the most problems. This article aims to summarise the available information on the correct identification of the main human pathogenic bacteria through the use of MALDI-TOF MS, focusing on Gram-negative, Grampositive and anaerobic microorganisms. The main factors that must be taken into account for the reliable identification of any bacterium are the conditions for culture, sample preparation with the ideal extraction method and especially the use of a correct and updated database

First reported case of a corneal abscess caused by Massilia timonae / Primer caso descrito de absceso corneal causado por Massilia timonae

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Variantes pequeñas de Staphylococcus aureus: utilidad de distintas pruebas para su diagnóstico y estudio de sensibilidad / Small-colony variants of Staphylococcus aureus: Usefulness of various test for diagnosis and susceptibility study

INTRODUCCIÓN: Las variantes de colonia pequeña de Staphylococcus aureus (VCPSA) constituyen una subpoblación con características especiales. Métodos Se estudió el comportamiento fenotípico y la sensibilidad antibiótica de 4 aislados clínicos de VCPSA. Resultados Las colonias crecieron en los medios de cultivo habituales excepto en Mueller Hinton. Todos los aislados fueron resistentes a ciprofloxacino y cotrimoxazol. Discusión Las VCPSA son aisladas con baja frecuencia, y es necesario conocer los métodos óptimos para su identificación y el estudio de su sensibilidad antibiótica

INTRODUCTION: Small colony variants of Staphylococcus aureus (SCVSA) are a sub-population with special features. METHODS: The phenotypic features and antibiotic susceptibility of four clinical isolates SCVSA were studied. RESULTS: Colonies grew in the usual culture media, except in Mueller Hinton. All isolates were resistant to ciprofloxacin and co-trimoxazole. DISCUSSION: As SCVSA are isolated with low frequency, it is necessary to determine the optimal methods for their identification and antibiotic susceptibility study

[Small-colony variants of Staphylococcus aureus: Usefulness of various test for diagnosis and susceptibility study]. / Variantes pequeñas de Staphylococcus aureus: utilidad de distintas pruebas para su diagnóstico y estudio de sensibilidad.

INTRODUCTION: Small colony variants of Staphylococcus aureus (SCVSA) are a sub-population with special features. METHODS: The phenotypic features and antibiotic susceptibility of four clinical isolates SCVSA were studied. RESULTS: Colonies grew in the usual culture media, except in Mueller Hinton. All isolates were resistant to ciprofloxacin and co-trimoxazole. DISCUSSION: As SCVSA are isolated with low frequency, it is necessary to determine the optimal methods for their identification and antibiotic susceptibility study.

[Molecular typing methods for infection monitoring and control]. / Técnicas de tipificación molecular para la vigilancia y control de la infección.

Molecular typing methods are useful in the surveillance and control of nosocomial outbreaks because they can provide information on the clonal relatedness among isolates, identify reservoirs, and determine routes of transmission. The gold standard assay for molecular typing is pulsed-field gel electrophoresis (PFGE) due to its high discriminatory power. Some major disadvantages of PFGE include the high cost of the equipment, its labor intensiveness (the technique is not automated) and the time required to analyze the profiles of DNA bands (pulsotypes). Although there are many molecular typing methods based on polymerase-chain reaction (PCR), the most widely used is repetitive sequence-based PCR (REP-PCR). Most of the PCR techniques used for molecular typing have none of the limitations of PFGE as they are less expensive and labor intensive (some, such as bioMérieux's Diversilab system, are commercially available) and generate DNA profiles that are easier to interpret, depending on the microorganism. The discriminatory power of PCR is generally lower than or similar to that of PFGE. Both PFGE and PCR require optimal laboratory standardization to guarantee good reproducibility. PCR methods are preferable in the study of small, timelimited outbreaks. In more complex outbreaks of longer duration, in which clonal evolution and dynamics are studied, the use of PFGE is preferable. Molecular typing methods based on DNA sequencing, such as multilocus sequence typing, are applicable in global epidemiological studies or in analyses of the population structure of microorganisms.

Técnicas de tipificación molecular para la vigilancia y control de la infección / Molecular typing methods for infection monitoring and control

Las técnicas de tipificación molecular son útiles en la vigilancia y control de brotes porque permiten conocer la clonalidad entre aislados, identificar reservorios y determinar vías de transmisión. La electroforesis en campo pulsado (ECP) es la técnica de referencia de tipificación debido a que tiene un elevado poder de discriminación. Entre las limitaciones más importantes de la ECP están el elevado coste del equipo, su laboriosidad y el tiempo necesario para analizar los pulsotipos. Aunque hay numerosas técnicas de tipificación basadas en la reacción en cadena de la polimerasa (PCR), la más utilizada es la PCR de secuencias de ADN repetidas (REP-PCR). Estas técnicas son más económicas, menos laboriosas (algunas son semiautomatizadas y están comercializadas, como el Diversilab de bioMérieux), y suelen generar patrones de bandas relativamente más fáciles de interpretar que la ECP. El poder de discriminación de las técnicas de PCR puede ser inferior o similar al de la ECP. Tanto la ECP como las técnicas de PCR tienen que optimizarse o estandarizarse en el laboratorio para garantizar una buena reproducibilidad. Para el estudio de brotes pequeños y de corta evolución, en los que interesa obtener una información con rapidez, es preferible utilizar una técnica de PCR. En brotes más complejos y de mayor duración, en los que interesa conocer además la evolución o dinámica de los clones con el tiempo, es más rentable utilizar la ECP. Los métodos de tipificación basados en la secuenciación del ADN, como el MLST, se utilizan para estudios epidemiológicos globales o para analizar la estructura poblacional de los microorganismos

Molecular typing methods are useful in the surveillance and control of nosocomial outbreaks because they can provide information on the clonal relatedness among isolates, identify reservoirs, and determine routes of transmission. The gold standard assay for molecular typing is pulsed-field gel electrophoresis (PFGE) due to its high discriminatory power. Some major disadvantages of PFGE include the high cost of the equipment, its labor intensiveness (the technique is not automated) and the time required to analyze the profiles of DNA bands (pulsotypes). Although there are many molecular typing methods based on polymerase-chain reaction (PCR), the most widely used is repetitive sequence-based PCR (REP-PCR). Most of the PCR techniques used for molecular typing have none of the limitations of PFGE as they are less expensive and labor intensive (some, such as bioMérieux's Diversilab system, are commercially available) and generate DNA profiles that are easier to interpret, depending on the microorganism. The discriminatory power of PCR is generally lower than or similar to that of PFGE. Both PFGE and PCR require optimal laboratory standardization to guarantee good reproducibility. PCR methods are preferable in the study of small, timelimited outbreaks. In more complex outbreaks of longer duration, in which clonal evolution and dynamics are studied, the use of PFGE is preferable. Molecular typing methods based on DNA sequencing, such as multilocus sequence typing, are applicable in global epidemiological studies or in analyses of the population structure of microorganisms

Impacto de las revistas biomédicas españolas / Impact of Spanish biomedical journals

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