[Levofloxacin prophylaxis in neutropenic patients]. / Profilaxis con levofloxacina en pacientes neutropénicos.

Fluorquinolone-prophylaxis has proven useful in preventing infections in high risk neutropenic patients. The objective of this study was to describe the clinical, microbiological and therapeutic characteristics, and outcome of patients in the first episode of febrile neutropenia, comparing those who received levofloxacin prophylaxis with those who didn't. It was a prospective observational study that included all the episodes of inpatients with febrile neutropenia (February 1997- November 2014), also including the first episode in a same patient in different hospitalizations. Of 946 episodes here included, 821 presented high risk febrile neutropenia. A total of 264 cases (27.9%) received levofloxacin prophylaxis. This group consisted of a higher proportion of high risk febrile neutropenia (99.2% vs. 82.3%, p = 0.0001) and patients that had received an hematopoietic stem cell transplant (67.8% vs. 29.3%, p = 0.0001) compared to those who didn't receive prophylaxis. Those who received levofloxacin prophylaxis presented a similar frequency of clinically diagnosed but a lower proportion of microbiologically documented infections (28.8% vs. 37.5%, p = 0.012) than those who didn't receive prophylaxis. The episodes of bacteremia that occurred in the first group were more frequently caused by multidrug resistant bacteria (MDRB) (34.5% vs. 17.3%, p = 0.007) and by extended spectrum beta lactamase producing Enterobacteriaceae (19% vs. 3.8%, p = 0.0001). The group that received prophylaxis had a lower proportion of adequate empirical antibiotic treatment (69.7% vs. 83.7%, p = 0.009), with similar outcomes in both groups. We suggest that levofloxacin prophylaxis should be stopped whenever there is a rise in the frequency of MDRB infections in this population.

[Evaluation of mass spectrometry: MALDI-TOF MS for fast and reliable yeast identification]. / Evaluación de la espectrometría de masas: MALDI-TOF MS para la identificación rápida y confiable de levaduras.

The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique known as MALDI-TOF MS is a tool used for the identification of clinical pathogens by generating a protein spectrum that is unique for a given species. In this study we assessed the identification of clinical yeast isolates by MALDI-TOF MS in a university hospital from Argentina and compared two procedures for protein extraction: a rapid method and a procedure based on the manufacturer's recommendations. A short protein extraction procedure was applied in 100 isolates and the rate of correct identification at genus and species level was 98.0%. In addition, we analyzed 201 isolates, previously identified by conventional methods, using the methodology recommended by the manufacturer and there was 95.38% coincidence in the identification at species level. MALDI TOF MS showed to be a fast, simple and reliable tool for yeast identification.

[Utility of MALDI-TOF MS for the identification of anaerobic bacteria]. / Utilidad de la espectrometría de masas MALDI-TOF en la identificación de bacterias anaerobias.

The analysis by MALDI-TOF MS (Matrix-assited laser desorption/ionization time-of-flight mass spectrometry) has become a reference method for the identification of microorganisms in Clinical Microbiology. However, data on some groups of microorganisms are still controversial. The aim of this study is to determine the utility of MALDI-TOF MS for the identification of clinical isolates of anaerobic bacteria. One-hundred and six anaerobic bacteria isolates were analyzed by MALDI-TOF MS and by conventional biochemical tests. In those cases where identification by conventional methodology was not applicable or in the face of discordance between sequencing methodologies, 16 S rRNA gene sequence analysis was performed. The conventional method and MALDI-TOF MS agreed at genus and species level by 95.3 %. Concordance in gram-negative bacilli was 91.4% and 100% among gram-positive bacilli; there was also concordance both in the 8 isolates studied in gram-positive cocci and in the single gram-negative cocci included. The data obtained in this study demonstrate that MALDI-TOF MS offers the possibility of adequate identification of anaerobic bacteria.

[Non-O1, non-O139 Vibrio cholerae bacteremia in a chronic hemodialysis patient]. / Bacteriemia por Vibrio cholerae no-O1, no-O139 en un paciente en hemodiálisis crónica.

Non-O1, and non-O139 Vibrio cholerae is an infrequent cause of bacteremia. There are no reports of such bacteremia in chronic hemodialysis patients. This work describes the case of a chronic hemodialysis patient that had an episode of septicemia associated with dialysis. Blood cultures were obtained and treatment was begun with vancomycin and ceftazidime. After 6.5 hours of incubation in the Bact/Alert system there is evidence of gram-negative curved bacilli that were identified as Vibrio cholerae by conventional biochemical tests, API 20 NE and the VITEK 2 system. This microorganism was sent to the reference laboratory for evaluation of serogroup and virulence factors and was identified as belonging to the non-O1 and non-O139 serogroup. The cholera toxin, colonization factor and heat-stable toxin were not detected. The isolate was susceptible to ampicillin, trimethoprim-sulfamethoxazole, ciprofloxacin, tetracycline, ceftazidime and cefotaxime by the disk diffusion method and the VITEK 2 system. The patient received intravenous ceftazidime for a 14 day- period and had a favorable outcome.

Antibiotic Resistance in Community-Acquired Intra-Abdominal Infections: Diabetes Mellitus as a Risk Factor.

Background: Antimicrobial drug resistance in community-acquired (CA) infections is a growing problem. Knowing the local epidemiology is essential to design empirical antibiotic therapy. Therefore, we conducted this study to evaluate the resistance patterns of microorganisms isolated from surgical samples of community-acquired intra-abdominal infections (IAIs) and to determine the factors associated with resistance. Methods: We analyzed retrospectively the records of patients treated from January 2015 to June 2017 who had IAIs with positives aerobic cultures performed in the first 72 hours after admission. Surgical site infections, abdominal wall procedures, peritoneal dialysis catheters, and patients with admissions in the prior month were excluded. To identify the factors associated with resistance, we considered the resistance to the regimen recommended at our institution, ampicillin/sulbactam (AMS) plus ciprofloxacin (CIP). Results: There were 119 patients with 133 isolates, 59% women, and mean age 54 years. The main sources of infection were appendicitis (38%) and cholecystitis (20%), with 64 patients presenting a complicated IAI (cIAI), defined by the presence of peritonitis (55%). Resistance in Enterobacteriaceae was AMS 32% (6.4% intermediate resistance), CIP 31%, cefotaxime 9%, piperacillin/tazobactam (PTZ) 3%, trimethoprim/sulfamethoxazole 32%, gentamicin 9.5%, and amikacin 2%. Considering all patients, resistance to AMS + CIP was 16.8%. Factors associated with resistant to this regimen was, by univariable and multivariable analysis, the presence of diabetes mellitus (odds ratio [OR] 3.6; 95% confidence interval [CI] 1.1-11.6; p = 0.03). Female gender (OR 2.7; CI 0.9-8.4; p = 0.08) and complicated IAI (OR 2.0; CI 0.7-5.4; p = 0.17) were associated with resistance but did not reach statistical significance. Conclusion: High resistance to CIP and AMS was observed. Although the combination of AMS + CIP offers coverage for 84% of patients, PTZ should be considered as an option for patients with severe infections or diabetes mellitus. Finding factors associated with antibiotic resistance could help to select empirical therapy for CA IAIs better.

[Post-surgery cerebral abscess due to Propionibacterium acnes]. / Absceso cerebral posquirúrgico causado por Propionibacterium acnes.

Brain abscesses by Propioni-bacterium acnes are rare. The rapid identification of this pathogen is important in order to choice the appropriate antibiotic therapy. We describe the case of a patient with excision of a multiform glioblastoma who 9 months later presented a tumor recurrence. A subtotal tumor excision was made and implants chemotherapy were placed in the residual tumor. After one month of surgery the patient presented a brain abscess. A craniotomy for drainage was performed. P. acnes was isolated from the biopsy and from purulent material. Identification was made by conventional biochemical tests and by the API system 20 A. The Minimum Inhibitory Concentration (MIC) to clindamycin, penicillin, amoxicillin and metronidazole was determined. The values of MIC (microg/ml) obtained were: 0.250, 0.040, 0.023 and 256, respectively. The patient received cefepime and metronidazole intravenously during 30 days and completed treatment with oral clindamycin for 60 days, considering the possibility of adjacent bone involvement. Eight months after the drainage the patient had no evidence of infection or tumor recurrence. Although P. acnes is a rare cause of post-neurosurgical infection, it should be considered as a possible pathogen in postoperative brain abscesses.

Evaluación de la espectrometría de masas: MALDI-TOF MS para la identificación rápida y confiable de levaduras / Evaluation of mass spectrometry: MALDI-TOF MS for fast and reliable yeast identification

La espectrometría de masas, conocida como matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), es una técnica utilizada en la identificación de microorganismos mediante la creación de un espectro basado en el perfil de proteínas, que es único para una especie dada. El objetivo del presente trabajo fue evaluar la identificación de aislamientos clínicos de levaduras por MALDI-TOF MS en un hospital universitario de Argentina y analizar 2 procedimientos para la extracción de proteínas: el recomendado por el fabricante del equipo y una técnica abreviada rápida. Utilizando el primero de estos procedimientos se analizaron 201 aislamientos identificados previamente por métodos convencionales y se obtuvo coincidencia en la identificación a nivel de especie en el 95,38% de los aislamientos analizados. Con 100 de estos aislamientos se utilizó, además, el procedimiento abreviado para la extracción de proteínas; se obtuvo una identificación correcta a nivel de género y especie en el 98,0% de ellos. La espectrometría de masas MALDI-TOF MS demostró ser una técnica rápida, sencilla y precisa para la identificación de levaduras

The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique known as MALDI-TOF MS is a tool used for the identification of clinical pathogens by generating a protein spectrum that is unique for a given species. In this study we assessed the identification of clinical yeast isolates by MALDI-TOF MS in a university hospital from Argentina and compared two procedures for protein extraction: a rapid method and a procedure based on the manufacturer's recommendations. A short protein extraction procedure was applied in 100 isolates and the rate of correct identification at genus and species level was 98.0%. In addition, we analyzed 201 isolates, previously identified by conventional methods, using the methodology recommended by the manufacturer and there was 95.38% coincidence in the identification at species level. MALDI TOF MS showed to be a fast, simple and reliable tool for yeast identification

Utilidad de la espectrometría de masas MALDI-TOF en la identificación de bacterias anaerobias / Utility of MALDI-TOF MS for the identification of anaerobic bacteria

El análisis de espectrometría de masas mediante la metodología hoy conocida como MALDI-TOF MS (Matrix-assited laser desorption/ionization time-of-flight mass spectrometry) se ha convertido en un recurso de referencia para la identificación de microorganismos en microbiología clínica. No obstante, los datos relativos a algunos grupos de microorganismos son todavía controvertidos. El objetivo del presente estudio fue determinar la utilidad del MALDI-TOF MS para la identificación de aislamientos clínicos de bacterias anaerobias. Se analizaron 106 aislamientos de bacterias anaerobias mediante MALDI-TOF MS y por pruebas bioquímicas convencionales. En aquellos casos en los que la identificación por metodología convencional no era aplicable o frente a una discordancia de resultados entre las metodologías citadas, se realizó la secuenciación del gen 16S del ARNr. El método convencional y el MALDI-TOF MS coincidieron a nivel de género y especie en un 95,3 % de los casos considerando la totalidad de los aislamientos estudiados. Al considerar solo el conjunto de los bacilos gram negativos, la coincidencia fue del 91,4 %; entre los bacilos gram positivos, fue del 100 %; los 8 aislados de cocos gram positivos estudiados coincidieron y también hubo coincidencia en el único coco gram negativo incluido. Los datos obtenidos en este estudio demuestran que el MALDI-TOF MS ofrece la posibilidad de llegar a una adecuada identificación de bacterias anaerobias

The analysis by MALDI-TOF MS (Matrix-assited laser desorption/ionization time-of-flight mass spectrometry) has become a reference method for the identification of microorganisms in Clinical Microbiology. However, data on some groups of microorganisms are still controversial. The aim of this study is to determine the utility of MALDI-TOF MS for the identification of clinical isolates of anaerobic bacteria. One-hundred and six anaerobic bacteria isolates were analyzed by MALDI-TOF MS and by conventional biochemical tests. In those cases where identification by conventional methodology was not applicable or in the face of discordance between sequencing methodologies, 16 S rRNA gene sequence analysis was performed. The conventional method and MALDI-TOF MS agreed at genus and species level by 95.3 %. Concordance in gram-negative bacilli was 91.4% and 100% among gram-positive bacilli; there was also concordance both in the 8 isolates studied in gram-positive cocci and in the single gram-negative cocci included. The data obtained in this study demonstrate that MALDI-TOF MS offers the possibility of adequate identification of anaerobic bacteria

Bacteriemia por Vibrio cholerae no-O1, no-O139 en un paciente en hemodiálisis crónica / Non-O1, non-O139 Vibrio cholerae bacteremia in a chronic hemodialysis patient

Vibrio cholerae no-O1, no-O139 es un agente poco frecuente como causal de bacteriemias y no hay informes que documenten su presencia en pacientes en hemodiálisis crónica. Se describe el caso de una paciente en hemodiálisis crónica que presentó un cuadro de sepsis, por lo cual inició un tratamiento con vancomicina y ceftacidima. Al cabo de seis horas y media de incubación en el sistema BACT/ALERT de hemocultivo, se evidenció la presencia de bacilos curvos gram negativos, posteriormente identificados como Vibrio cholerae mediante pruebas bioquímicas convencionales y el uso de los kits API 20 NE y VITEK 2. La evaluación del serogrupo y de la presencia de factores de patogenicidad, realizada en el laboratorio de referencia, determinó que el microorganismo hallado pertenecía al serogrupo no-O1, no-O139. No se detectó la toxina de cólera, tampoco el factor de colonización ni la toxina termoestable. El aislamiento presentó sensibilidad frente a ampicilina, trimetoprima-sulfametoxazol, ciprofloxacina, tetraciclina, ceftacidima y cefotaxima por el método de difusión con discos y por VITEK 2. La paciente cumplió 14 días de tratamiento con ceftacidima endovenosa, con evolución favorable.

Non-O1, and non-O139 Vibrio cholerae is an infrequent cause of bacteremia. There are no reports of such bacteremia in chronic hemodialysis patients. This work describes the case of a chronic hemodialysis patient that had an episode of septicemia associated with dialysis. Blood cultures were obtained and treatment was begun with vancomycin and ceftazidime. After 6.5 hours of incubation in the Bact/Alert system there is evidence of gram-negative curved bacilli that were identified as Vibrio cholerae by conventional biochemical tests, API 20 NE and the VITEK 2 system. This microorganism was sent to the reference laboratory for evaluation of serogroup and virulence factors and was identified as belonging to the non-O1 and non-O139 serogroup. The cholera toxin, colonization factor and heat-stable toxin were not detected. The isolate was susceptible to ampicillin, trimethoprim-sulfamethoxazole, ciprofloxacin, tetracycline, ceftazidime and cefotaxime by the disk diffusion method and the VITEK 2 system. The patient received intravenous ceftazidime for a 14 day- period and had a favorable outcome.

Absceso cerebral posquirúrgico causado por Propionibacterium acnes / Post-surgery cerebral abscess due to Propionibacterium acnes

Los abscesos cerebrales por Propionibacterium acnes son poco frecuentes. Es importante para el médico clínico la rápida identificación de este patógeno para la elección de una terapéutica antibiótica adecuada. En este caso se describe un paciente con una exéresis de un glioblastoma multiforme donde a los 9 meses se evidenció la existencia de una recidiva tumoral, se efectuó una extirpación tumoral subtotal y la colocación de implantes de quimioterapia en el lecho tumoral residual. Al cabo de un mes de esta reoperación presentó una lesión ocupante compatible con un absceso cerebral, motivo por el cual se realizó nueva craneotomía y drenaje del mismo. En los cultivos de las biopsias y del material purulento se aisló P. acnes como flora única. Para la identificación se realizaron pruebas bioquímicas y se aplicó el sistema API20A. Se determinó la concentración inhibitoria mínima (CIM) a clindamicina, penicilina, amoxicilina y metronidazol, los valores de CIM (ug/ml) obtenidos fueron: 0.250, 0.040, 0.023 y 256, respectivamente. El paciente recibió cefepime más metronidazol por vía endovenosa durante un período de 30 días y completó tratamiento con clindamicina por vía oral durante 60 días, dada la posible complicación ósea en el sitio de la infección. Luego de 8 meses de la intervención quirúrgica y el drenaje del absceso cerebral no hubo evidencia de signos clínicos de recidiva tumoral e infecciosa. P. acnes es un patógeno infrecuente como causal de abscesos cerebrales, sin embargo no se debe desestimar en muestras neuroquirúrgicas.

Brain abscesses by Propionibacterium acnes are rare. The rapid identification of this pathogen is important in order to choice the appropriate antibiotic therapy. We describe the case of a patient with excision of a multiform glioblastoma who 9 months later presented a tumor recurrence. A subtotal tumor excision was made and implants chemotherapy were placed in the residual tumor. After one month of surgery the patient presented a brain abscess. A craniotomy for drainage was performed. P. acnes was isolated from the biopsy and from purulent material. Identification was made by conventional biochemical tests and by the API system 20 A. The Minimum Inhibitory Concentration (MIC) to clindamycin, penicillin, amoxicillin and metronidazole was determined. The values of MIC (ug/ml) obtained were: 0.250, 0.040, 0.023 and 256, respectively. The patient received cefepime and metronidazole intravenously during 30 days and completed treatment with oral clindamycin for 60 days, considering the possibility of adjacent bone involvement. Eight months after the drainage the patient had no evidence of infection or tumor recurrence. Although P. acnes is a rare cause of post-neurosurgical infection, it should be considered as a possible pathogen in postoperative brain abscesses.