Marcadores hematológicos y bioquímicos para el diagnóstico precoz de bacteriemiascausadas por Enterobacteriaceae resistentes a los carbapenémicos / Haematological and biochemical markers for the early diagnosis of bacteremias caused bycarbapenem-resistant Enterobacteriaceae

INTRODUCCIÓN. Las bacteriemias causadas por Enterobacteriaceae resistentes a carbapenémicos se asocian con altas tasas de mortalidad a diferencia de las bacteriemias causadas por Enterobacteriaceae sensibles a carbapenémicos. Los hallazgos clínicos y de laboratorio son importantes para determinar los esquemas terapéuticos y su pronóstico; su diagnóstico precoz resulta esencial para un manejo adecuado. OBJETIVO. Relacionar valores de marcadores sanguíneos y bioquímicos en bacteriemias causadas por Enterobacteriaceae resistentes a carbapenémicos. MATERIALES Y MÉTODOS. Estudio analítico transversal. Población de 427 y muestra de 224 datos de hemocultivos positivos para Enterobacteriaceae de pacientes atendidos en el Hospital de Especialidades Carlos Andrade Marín en el periodo mayo 2016 a julio 2018. Criterios de inclusión: i) al menos un hemocultivo positivo; ii) recuperación del aislado de CRE o CSE y iii) recolección simultanea de muestras de sangre y pruebas de laboratorio. Criterios de exclusión: i) bacteriemias polimicrobianas; ii) valores fuera de rango y iii) reportes sin valores numéricos. El análisis de datos se realizó mediante el programa estadístico International Business Machines Statistical Package for the Social Sciences versión 24.0. RESULTADOS. Se demostró que el recuento de leucocitos [OR 1,21 (95% IC: 1,03-1,43)], el recuento de plaquetas [OR 1,65 (95% IC: 1,37-1,98)] y el tiempo parcial de tromboplastina [OR 1,29 (95% IC: 1,04-1,60)] fueron buenas variables predictoras independientes, mediante análisis de regresión logística multivariante. CONCLUSIÓN. La trombocitopenia y el tiempo parcial de tromboplastina prolongado se asociaron con bacteremia causada por Enterobacteriaceae resistentes a carbapenémicos.

INTRODUCTION. Bacteremias caused by carbapenem-resistant Enterobacteriaceae are associated with high mortality rates in contrast to bacteremias caused by carbapenem-sensitive Enterobacteriaceae. Clinical and laboratory findings are important in determining therapeutic regimens and prognosis; early diagnosis is essential for appropriate management. OBJECTIVE. To relate blood and biochemical marker values in bacteremia caused by carbapenem-resistant Enterobacteriaceae. MATERIALS AND METHODS. Cross-sectional analytical study. Population of 427 and sample of 224 blood culture data positive for Enterobacteriaceae from patients attended at the Carlos Andrade Marín Specialties Hospital in the period May 2016 to July 2018. Inclusion criteria: i) at least one positive blood culture; ii) recovery of CRE or CSE isolate and iii) simultaneous collection of blood samples and laboratory tests. Exclusion criteria: i) polymicrobial bacteremia; ii) out-of-range values and iii) reports without numerical values. Data analysis was performed using the statistical program International Business Machines Statistical Package for the Social Sciences version 24.0. RESULTS. Leukocyte count [OR 1.21 (95% CI: 1.03-1.43)], platelet count [OR 1.65 (95% CI: 1.37- 1.98)] and partial thromboplastin time [OR 1.29 (95% CI: 1.04-1.60)] were shown to be good independent predictor variables, by multivariate logistic regression analysis. CONCLUSION. Thrombocytopenia and prolonged partial thromboplastin time were associated with bacteremia caused by carbapenem-resistant Enterobacteriaceae.

Bacillus cereus bacteremia in a patient with an abdominal stab wound / Bacteriemia por Bacillus cereus en paciente con herida de arma blanca abdominal

Abstract Bacillus cereus is a gram positive microorganism commonly involved in gastrointestinal infection but capable of causing severe infections and bacteremia. We describe here a case of bacteremia caused by B. cereus in a previously healthy young woman admitted to the intensive care unit following emergency surgery due to a penetrating abdominal stab wound and subsequent hepatic lesion. She developed fever during admission and cultures were taken. B. cereus was isolated in blood and hepatic fluid collection cultures. Treatment was adjusted according to the isolate, with good clinical results. It is important to highlight the pathogenic potential of this microorganism and not underestimate it as a contaminant when it is isolated from blood samples.

Resumen Bacillus cereus es un microorganismo gram positivo comúnmente involucrado en infecciones gastrointestinales, pero capaz de causar infecciones graves y bacteriemia. Presentamos un caso de bacteriemia por B. cereus en una mujer joven previamente sana que ingresa en la unidad de cuidados intensivos luego de una cirugía de emergencia, debido a una herida abdominal por arma blanca con lesión hepática. La paciente desarrolla fiebre durante la internación, por lo que se toman cultivos. Se aísla B. cereus en hemocultivos y material de colección hepática. Se ajusta el tratamiento según los hallazgos, con buena evolución clínica. Esta comunicación ilustra una fuente poco común de bacteriemia por B. cereus. Asimismo, destaca el potencial patogénico de este microorganismo, cuyo hallazgo en muestras de sangre no siempre debe conducir a su rápida desjerarquización como contaminante.

Mycobacterium tuberculosis complex bacteremia among HIV and non-HIV patients in a Mexican tertiary care center

ABSTRACT Objectives: To determine the factors associated with Mycobacterium tuberculosis complex-positive blood culture. Methods: Case-control study. Sociodemographic, clinical and laboratory data were collected from 2000 to 2015. Results: We reviewed medical records of 533 patients with culture-proven tuberculosis, of whom 27.2% (145/533) had blood culture available. Patients with mycobacteremia presented more frequently with abdominal tuberculosis, body mass index <18 kg/m2, and had lower hemoglobin and albumin levels. No differences were observed regarding HIV status. Conclusions: Few studies have reported on the characteristics associated with Mycobacterium tuberculosis complex bacteremia, especially among Human Immunodeficiency Virus-negative patients. Out of 145 tuberculosis-infected patients with blood culture results available, 21 turned out positive. Anemia, hypoalbuminemia, and a body mass index < 18 kg/m2 were associated with mycobacteremia.

Diagnostic and prognostic performances of serum procalcitonin in patients with bloodstream infections: A parallel, case-control study comprising adults and elderly

Summary Objective: To examine the diagnostic and prognostic performances of serum procalcitonin (PCT) in adult and elderly patients with bloodstream infections (BSIs). Method: A total of 176 patients with culture-proven BSIs and 200 healthy counterparts were studied prospectively. Participants were studied in two adult (age≤65 years, n=92) and elderly (age>65 years, n=84) groups. Admission serum PCT level was measured using a standard enzyme-linked immunosorbent assay (ELISA) technique. Results: The mean serum PCT level (in ng/mL) was significantly higher in cases than in controls (0.18 vs. 0.07, p=0.01 in adults; 0.20 vs. 0.07, p=0.002 in elderly). At cut-off values of 0.09 ng/mL in adults and 0.08 ng/mL in the elderly, the corresponding sensitivity and specificity were 82.6 and 82.0% in adults, and 69.1 and 70.0% in elderly, respectively. At a cut-off value of 0.2 ng/mL, the sensitivity and specificity of serum PCT in predicting 28-day mortality were 81 and 81.7% in adults, and 75 and 80.4% in elderly, respectively. Conclusion: Although admission serum PCT is a sensitive and specific biomarker for the diagnosis of BSIs in patients younger than 65 years old, its short-term prognostic value is comparable between adults and the elderly.

Can procalcitonin be a diagnostic marker for catheter-related blood stream infection in children? / A procalcitonina pode ser um marcador de diagnóstico de infecções de corrente sanguínea relacionadas a cateter em crianças?

Abstract Objective The potential role of procalcitonin (PCT) in the diagnosis of catheter-related bloodstream infection (CRBSIs) is still unclear and requires further research. The diagnostic value of serum PCT for the diagnosis of CRBSI in children is evaluated here. Method This study was conducted between October 2013 and November 2014, and included patients with suspected CRBSI from 1 month to 18 years of age who were febrile, with no focus of infection, and had a central venous catheter. Levels of PCT and other serum markers were measured, and their utility as CRBSI markers was assessed. Additionally, the clinical performance of a new, automated, rapid, and quantitative assay for the detection of PCT was tested. Results Among the 49 patients, 24 were diagnosed with CRBSI. The PCT-Kryptor and PCT-RTA values were significantly higher in proven CRBSI compared to those in unproven CRBSI (p = 0.03 and p = 0.03, respectively). There were no differences in white blood cell count and C-reactive protein (CRP) levels between proven CRBSI and unproven CRBSI. Among the 24 patients with CRBSI, CRP was significantly higher among those with Gram-negative bacterial infection than in those with Gram-positive bacterial infections. PCT-Kryptor was also significantly higher among patients with Gram-negative bacterial infection than in those with Gram-positive bacterial infections (p = 0.01 and p = 0.02, respectively). Conclusions The authors suggest that PCT could be a helpful rapid diagnostic marker in children with suspected CRBSIs.

Resumo Objetivo O possível papel da procalcitonina (PCT) no diagnóstico de infecções de corrente sanguínea relacionadas a cateter (ICSRCs) ainda não está claro e precisa ser mais pesquisado. O valor diagnóstico da PCT sérica para o diagnóstico de ICSRC em crianças é avaliado neste estudo. Método Este estudo foi feito entre outubro de 2013 e novembro de 2014 e incluiu pacientes com suspeita de ICSRC de um mês a 18 anos que estavam febris, não tinham foco de infecção e tinham cateter venoso central. Foram medidos os níveis de PCT e de outros marcadores séricos, cuja utilidade como marcadores de ICSRC foi avaliada. Adicionalmente, foi testado o desempenho clínico de um novo ensaio quantitativo automatizado e rápido para a detecção de PCT. Resultados Dentre 49 pacientes, 24 foram diagnosticados com ICSRC. Os valores de PCT-Kryptor e PCT-RTA foram significativamente maiores em ICSRCs comprovadas do que em ICSRCs não comprovadas (p = 0,03 e p = 0,03, respectivamente). Não houve diferença na contagem de glóbulos brancos e nos níveis de proteína C reativa (PCR) entre ICSRCs comprovadas e ICSRCs não comprovadas. Dentre os 24 pacientes com ICSRC, a PCR era significativamente maior entre aqueles com infecção bacteriana gram-negativa do que naqueles com infecção bacteriana gram-positiva. O PCT-Kryptor também foi significativamente maior entre pacientes com infecção por bactérias gram-negativas do que naqueles com infecção por bactérias gram-positivas (p = 0,01 e p = 0,02, respectivamente). Conclusões Sugerimos que a PCT pode ser um marcador de diagnóstico rápido útil em crianças com suspeita de ICSRCs.

Desarrollo y validación de un modelo predictor para bacteriemia en pacientes hospitalizados por el servicio de urgencias con sospecha de infección / Development and validation of a predictive model for bacteremia in patients hospitalized by the emergency department with suspected infection

Background: Positive blood cultures usually indicate disseminated infection that is associated with a poor prognosis and higher mortality. We seek to develop and validate a predictive model to identify factors associated with positive blood cultures in emergency patients. Methods: Secondary analysis of data from two prospective cohorts (EPISEPSIS: developing cohort, and DISEPSIS: validation cohort) of patients with suspected or confirmed infection, assembled in emergency services in 10 hospitals in four cities in Colombia between September 2007 and February 2008. A logistic multivariable model was fitted to identify clinical and laboratory variables predictive of positive blood culture. Results: We analyzed 719 patients in developing and 467 in validation cohort with 32% and 21% positive blood cultures, respectively. The final predictive model included variables with significant coefficients for both cohorts: temperature > 38° C, Glasgow < 15 and platelet < 150.000 cells/mm³, with calibration (goodness-of-fit H-L) p = 0.0907 and p = 0.7003 and discrimination AUC = 0.68 (95% CI = 0.65-0.72) and 0.65 (95% CI = 0.61-0.70) in EPISEPSIS and DISEPSIS, respectively. Specifically, temperature > 38 °C and platelets < 150.000 cells/mm³ and normal Glasgow; or Glasgow < 15 with normal temperature and platelets exhibit a LR between 1,9 (CI 95% = 1,2-3,1) and 2,3 (CI 95% = 1,7-3,1). Glasgow < 15 with any of low platelets or high temperature shows a LR between 2,2 (CI 95% = 1,1-4,4) and 2,6 (CI 95% = 1,7-4,3). Discussion: Temperature > 38° C, platelet count < 150,000 cells/mm³ and GCS < 15 are variables associated with increased likelihood of having a positive blood culture.

Introducción: Un hemocultivo positivo usualmente indica infección diseminada, la que se asocia con peor pronóstico y mayor mortalidad. Por tanto, buscamos desarrollar y validar un modelo de predicción que permita identificar los factores asociados con la positividad de los hemocultivos en pacientes del servicio de urgencias. Métodos: Análisis secundario de datos de dos cohortes prospectivas (EPISEPSIS: cohorte de desarrollo y DISEPSIS: cohorte de validación) de pacientes con sospecha o confirmación de infección, ensambladas en servicios de urgencias de 10 instituciones hospitalarias en cuatro ciudades de Colombia entre septiembre de 2007 y febrero de 2008. Se ajustó un modelo logístico multivariado para identificar variables clínicas y de laboratorio predictoras de hemocultivos positivos. Resultados: Se analizaron 719 pacientes en la cohorte de desarrollo y 467 en la cohorte de validación, con 32 y 21% de hemocultivos positivos, respectivamente. El modelo predictor final incluyó las variables con coeficientes significativos para ambas cohortes: temperatura ≥ 38 °C, Glasgow < 15 y plaquetas ≤ 150.000 céls/mm³ con calibración (bondad de ajuste de H-L) p = 0,0907 y p = 0,7003 y discriminación AUC: 0,68 (IC 95%: 0,65-0,72) y 0,65 (IC 95%: 0,61-0,70) en EPISEPSIS y DISEPSIS, respectivamente. Temperatura ≥ 38 °C y recuento de plaquetas ≤ 150.000 céls/mm³ con Glasgow normal; o Glasgow < 15 con temperatura y plaquetas normales tiene un LR entre 1,9 (IC 95%: 1,2-3,1) y 2,3 (IC 95%: 1,7-3,1). La escala de Glasgow < 15 puntos junto con cualquiera entre recuento de plaquetas o temperatura alteradas tiene un LR entre 2,2 (IC 95%: 1,1-4,4) y 2,6 (IC 95%: 1,7-4,3). Discusión: La temperatura ≥ 38 °C, el recuento de plaquetas ≤ 150.000 céls/mm³ y la escala de Glasgow < 15 son las variables asociadas con mayor probabilidad de tener un hemocultivo positivo.

First Case Report of Human Infection With Ochrobactrum tritici Causing Bacteremia and Cholecystitis

No abstract available.

Evaluación de predictores clínicos de bacteriemia en adultos hospitalizados por neumonía adquirida en la comunidad / Evaluation of clinical predictors of bacteremia in adults hospitalized for community-acquired pneumonia

OBJETIVO: Identificar elementos clínicos sencillos que hagan posible determinar adecuadamente los casos con mayor probabilidad de presentar aislamientos bacterianos en los hemocultivos. MÉTODOS: Estudio de casos y controles con pacientes internados por neumonía adquirida en la comunidad entre 1998 y 2009, definiéndose como casos a los pacientes que presentaron hemocultivos positivos y como controles a aquellos con hemocultivos negativos. Se registraron variables demográficas y clínicas y se las sometió a un análisis bivariado. Las que presentaron diferencias estadísticamente significativas entre los grupos fueron introducidas en un modelo de regresión logística para definir predictores independientes y generar un modelo de predicción clínica. RESULTADOS: De los 322 pacientes estudiados, 15,2 por ciento tuvo hemocultivos positivos. Diez variables mostraron diferencias significativas, pero solo tres (temperatura <38°C, sodio <135 mEq/L y puntaje CURB-65) fueron seleccionadas para el análisis multivariado. El modelo desarrollado mostró escasa capacidad para predecir el resultado de los hemocultivos (R² = 0,176; Hosmer-Lemeshow: P = 0,338). CONCLUSIONES: Los datos obtenidos en esta serie no evidenciaron elementos clínicos con capacidad suficiente para predecir el resultado de los hemocultivos.

OBJECTIVE: Identify simple clinical elements that can be used to adequately determine the cases with the highest probability of presenting bacterial isolates in blood cultures. METHODS: Case-control study with patients hospitalized for community-acquired pneumonia from 1998-2009. Patients with positive blood cultures were defined as cases, and patients with negative blood cultures were defined as controls. The demographic and clinical variables were recorded and a bivariate analysis was conducted. The variables with statistically significant differences between the groups were introduced in a logistic regression model in order to define the independent predictors and generate a clinical prediction model. RESULTS: A total of 15.2 percent of the 322 patients studied had positive blood cultures. Ten variables showed significant differences, but only three variables (temperature <38°C, sodium <135 mEq/L and CURB-65 score) were selected for the multivariate analysis. The model developed showed limited capacity to predict the result of the blood cultures (R² = 0.176; Hosmer-Lemeshow: P = 0.338). CONCLUSIONS: The data obtained in this series did not demonstrate clinical elements with sufficient capacity to predict the result of the blood cultures.

Niveles bajos de procalcitonina ¿descartan bacteriemia en shock séptico adquirido en la unidad de cuidados intensivos? aprendizaje desde una serie de casos / Low levels of procalcitonin in the diagnosis of bacteremia in septic shock acquired in the intensive care unit

La procalcitonina representa un sustancial avance en el diagnóstico de infección bacteriana. Sin embargo, debe correlacionarse con el cuadro clínico y los otros marcadores de laboratorio ya que la sensibilidad reportada en bacteriemia es menor a 90 por ciento. Presentamos 6 pacientes críticos en shock séptico durante su estadía en la unidad de cuidados intensivos (UCI). Como parte de su estudio y porque en su mayoría se trataba de pacientes con causas de respuesta inflamatoria sistémica no infecciosas como cuadro de base, se solicitó la procalcitonina con la idea de discriminar. Estos pacientes habían sido tratados (o estaban en tratamiento) por alguna infección previa. Posteriormente, se demostró que 5 de los 6 pacientes tenían ambos hemocultivos positivos de los 2 tomados dentro del mismo día de la toma de procalcitonina con los valores promedio y desviación estándar: 0,66 +/- 0,44 ng/ml y un retraso de toma respecto al hemocultivo de 11,5 +/- 4,9 horas(siempre posterior a este último).Discusión: Se destaca que en esta serie de pacientes críticos en shock séptico y bacteriémicos, donde por nivel de gravedad gravedad y tiempo de toma de la procalcitonina sería esperable encontrar valores mayores a 2 ng/ml (asociado con sepsis para la mayoría de los laboratorios), situación claramente diferente. Dado lo complejo de los pacientes críticos y la cinética de la procalcitonina, su valor puntual aún bajo, no reemplaza al juicio clínico, que en estos casos fue correcto habiéndose iniciado tratamiento empírico y no suspendido sólo por un valor aislado.

Procalcitonin represents a substantial advance in the diagnosis of bacterial infection. However, it should correlate with the clinical and other laboratory markers, because the sensitivity reported in bacteraemia is less than 90 percent. We present six critical patients in septic shock during their stay in the intensive care unit (ICU). Because most of these were patients with noninfectious systemic inflammatory response, procalcitonin was requested with the idea of discriminating as part of the study. These patients had been treated (or were in treatment) for some previous infection. Subsequently, it was demonstrated that 5 of the 6 patients had positive blood cultures 2 of 2 the same day of collection of procalcitonin, with average values and standard deviation: 0.66 +/- 0.44 ng /ml. The sampling delay in respect of the blood culture was 11.5 +/- 4.9 hours (always after the latter). Discussion: It should be noted that these ICU patients in septic shock and bacteraemia, where by levels of severity and time of making the procalcitonin, it would be expected to find values greater than 2 ng / ml (associated with sepsis for most laboratories), a situation clearly different. Given the complexity of critically ill patients and the kinetics of procalcitonin, its precise value (still low), does not replace clinical assessment. In these cases the clinic was correct, beginning empirical treatment and not suspended it only by an isolated value.

Comprehensive Analysis of Blood Culture Performed at Nine University Hospitals in Korea / 대한진단검사의학회지

BACKGROUND: Optimal blood culture performance is critical for successful diagnosis and treatment of sepsis. To understand the status of blood culture, we investigated several aspects of the procedure at 9 university hospitals. METHODS: The process of ordering blood culture sets and sampling volume for adults and children was investigated from January 2010 to April 2010, while the positive rate of detection and growth of skin contaminants were compared in 2009. Microbial growth in aerobic and anaerobic bottles was investigated prospectively. RESULTS: A majority of the hospitals used 2 sets of bottles for adults and 1 bottle for children. The average blood volume in each set was 7.7 mL for adults and 2.1 mL for children. The positive rate of microorganisms was 8.0%, and the isolation rate of the normal flora of the skin was 2.1%. Bacterial growth rates in aerobic and anaerobic bottles only were 31.8% and 24.5% respectively. CONCLUSIONS: Ordering blood culture sets and sampling volumes did not comply with CLSI guidelines. However, the rate of positive cultures and skin contamination rates were acceptable. Anaerobic bottles are useful in enhancing the yield of microorganisms.

Utility of Procalcitonin as an Early Diagnostic Marker of Bacteremia in Patients with Acute Fever

PURPOSE: Procalcitonin (PCT) is a current, frequently used marker for severe bacterial infection. The aim of this study was to assess the ability of PCT levels to differentiate bacteremic from nonbacteremic patients with fever. We assessed whether PCT level could be used to accurately rule out a diagnosis of bacteremia. MATERIALS AND METHODS: Serum samples and blood culture were obtained from patients with fever between August 2008 and April 2009. PCT was analyzed using a VIDAS(R) B.R.A.H.M.S PCT assay. We reviewed the final diagnosis and patient histories, including clinical presentation and antibiotic treatment. RESULTS: A total of 300 patients with fevers were enrolled in this study: 58 with bacteremia (positive blood culture) (group I); 137 with local infection (group II); 90 with other diseases (group III); and 15 with fevers of unknown origin (group IV). PCT levels were significantly higher in patients with bacteremia than in those with non-bacteremia (11.9 +/- 25.1 and 2.5 +/- 14.7 ng/mL, respectively, p < 0.001). The sensitivity and specificity were 74.2% and 70.1%, respectively, at a cut-off value of 0.5 ng/mL. A serum PCT level of < 0.4 ng/mL accurately rules out diagnosis of bacteremia. CONCLUSION: In febrile patients, elevated PCT may help predict bacteremia; furthermore, low PCT levels were helpful for ruling out bacteremia as a diagnosis. Therefore, PCT assessment could help physicians limit the number of prescriptions for antibiotics.

Blood stream infections in cancer patients: A single center experience of isolates and sensitivity pattern.

Background : Up to 10% of patients who develop a nosocomial blood stream infection (BSI) in the hospital have an underlying malignancy. The treatment of infections in patients with malignancy often relies on the use of established guidelines along with the consideration of the local microbiology and antibiotic sensitivity patterns of possible etiologic agents. AIMS: This study attempts to identify the likely etiologic agents and the antibiotic sensitivity profile of BSIs in cancer patients. Settings and Design: This was a retrospective study. Methods and Material: The study was conducted at a tertiary care center for cancer patients, in which samples representing blood stream infections sent from the Medical Oncology services of the hospital during the year of 2007 were analysed. The microbiological profile and antibiotic sensitivity pattern of these isolates was studied. Results: There were 484 isolates that represented BSIs. The most common bacterial isolates from patients with cancer were Pseudomonas spp. (30.37%), Staphylococcus aureus (12.6%) and Acinetobacter spp. (11.57%). Meropenem was the most effective antibiotic with 71.2% sensitivity to the bacterial isolates it was tested against. Oxacillin resistance was seen in 18% of S. aureus isolates. Conclusion: Gram-negative bacteria were more common as etiologic agents of BSIs in cancer patients. The poor activity of the primary empirical agents for infections in cancer namely ceftazidime and piperacillin-tazobactam is alarming.Strict regulation of vancomycin use should be considered in areas where there is a low prevalence of methicillin-resistant S. aureus (MRSA).

Primary Shewanella algae Bacteremia Mimicking Vibrio Septicemia

Shewanella algae infections are rare in humans. Previously reported cases of S. algae have mainly been associated with direct contact with seawater. We report a case of primary S. algae bacteremia occurring after the ingestion of raw seafood in a patient with liver cirrhosis that presented a fulminent course of necrotizing fasciitis.

Identificación y sensibilidad de bacilos gram-negativos: Evaluación del uso de un sistema automatizado directamente de los frascos de hemocultivo / Identification and antimicrobial susceptibility of gram-negative bacilli: Evaluation of the use of automatic system directly from blood culture bottles

La rapidez en el informe de los hemocultivos es esencial en el manejo clínico-infectológico de pacientes con bacteriemia. En el presente estudio se evaluó la utilidad del sistema Vitek para la identificación y sensibilidad antimicrobiana partiendo de las botellas de hemocultivo. También se evaluó el método de sensibilidad antibiótica de difusión con discos partiendo directamente de las botellas de hemocultivo. En un período de un año se procesaron 101 botellas de hemocultivo que resultaron positivas con bacilos gram-negativos (71 aislamientos de enterobacterias y 26 de bacilos gram-negativos no fermentadores). Los resultados de identificación obtenidos partiendo de las botellas de hemocultivo se compararon con las pruebas manuales convencionales realizadas a partir de colonia aislada y los resultados de sensibilidad antibiótica, con el método de dilución en agar. El 86% de las enterobacterias fueron identificadas correctamente a nivel de especie y el 14% no fueron identificadas. El 92,3% de los bacilos gram-negativos no fermentadores fue identificado correctamente a nivel de especie, 3,8% fueron mal identificados y otros 3,8% no fueron identificados. La concordancia global en la sensibilidad fue del 92,7% para el sistema Vitek y del 89,9% para el método de difusión con discos. Se encontraron errores very major (0,1% y 0,4%), major (2,4% y 1,3%) y minor (7,6% y 5,5%) para difusión con discos y sistema Vitek respectivamente. La inoculación de las tarjetas Vitek a partir de las botellas de hemocultivo que contenían bacilos gram-negativos, otorgó resultados satisfactorios tanto de identificación como de sensibilidad antibiótica. El método de difusión con discos realizado a partir de las botellas de hemoculivos también resultó confiable, pero el sistema Vitek tiene la ventaja adicional de proveer resultados similares en tiempos menores.

Reducing the turnaround time of laboratory diagnosis of bacteremia by means of blood cultures is of paramount importance to perform an appropriate clinical management of septic patients. In the present study, the performance of Vitek system for identification and antimicrobial susceptibility and disk diffusion antibiotic susceptibility method, directly from positive blood culture bottles, were evaluated. During one year, 101 positive bottles with gram-negative bacilli (71 Enterobacteriaceae and 26 non-fermenting gram-negative rods) were selected at random, and identification and antimicrobial susceptibility were studied. Identification obtained using Vitek system directly from the bottles has been compared to conventional biochemical tests with previously isolated bacteria. In a similar way, results of antimicrobial susceptibility have been compared to those obtained by agar dilution method. A good identification at species level was obtained for 86% of Enterobacteriaceae while 14% could not be identified. Almost ninety three percent of non-fermenting gram-negative rods were correctly identified with 3.8% badly identified, and 3.8% not identified. Global concordance with the reference method in susceptibility was 92.7% for Vitek system and 89.9 for disk diffusion method. very major (0.1% and 0.4%), major (2.4% and 1.3%) and minor (7.6% and 5.5%) errors were found for the disk diffusion method and Vitek system respectively. Vitek results obtained from direct inoculation of blood culture bottles containing gram-negative bacilli were satisfactory for identification as well as for antimicrobial susceptibility. The disk diffusion method directly performed from the bottles also showed acceptable results. However the advantage of Vitek system was its ability to significantly reduce the turnaround time.

Blood cultures in paediatric patients: a study of clinical impact.

PURPOSE: Blood cultures form a critical part of evaluation of patients with suspected sepsis. The present study was undertaken to study the risk factors, duration of incubation for obtaining positive cultures and the clinical impact of the culture report. METHODS: A total of 220 samples from 107 pediatric patients presenting with suspected bacteraemia were processed aerobically. RESULTS: Cultures were positive in 18.7% of the samples. Most of the positive cultures were obtained after 24 hours of incubation of the broth and no isolates were obtained beyond day 4 of incubation. Therapy was modified in 54.23% of the patients after receipt of culture report. CONCLUSIONS: Incubation beyond four days (unless with specific indication like enteric fever) may be unnecessary for issuing a negative culture report. Repeated isolation of doubtful pathogens confirms true bacteraemia. Early culture report increases therapeutic compliance.

Lack of Toll-like Receptor 4 and 2 Polymorphisms in Korean Patients with Bacteremia

Toll-like receptors (TLRs) are pattern-recognition receptors that are important in innate immune responses to bacterial infection. The purpose of this study is to describe the prevalence of TLRs genetic variations in the bacteremic patients in Korea. A total of 154 patients with bacteremia and 179 healthy volunteers were included. The Asp299Gly and Thr399Ile allele of the TLR4 gene and Arg753Gln and Arg677Trp allele of the TLR2 gene were tested by PCR-RFLP. The DNA sequences were determined to confirm the PCR-RFLP results. Contrary to the expectation, no genetic polymorphisms were detected in both groups of this study, suggesting that it is very rare in Korean.