Ceftriaxone pharmacokinetics by a sensitive and simple LC-MS/MS method: Development and application.

Ceftriaxone is a third-generation cephalosporin, worldwide use as a first-line treatment for several infections, including life-threatening infections as meningitis or endocarditis. Nowadays, ceftriaxone use is changing, embracing high-dose schemes, new populations treated and requirement of dose individualization and optimization. These reasons warranted the development of new sensitive assays. This study aimed to develop and validate a fast and handy bioanalytical method for the quantification of ceftriaxone in human plasma covering a broad range of concentrations. The analysis was performed using high-performance liquid chromatography coupled to tandem mass spectrometry. Sample preparation was based on protein precipitation with acetonitrile followed by centrifugation. Chromatography separation was performed on Phenomenex Luna C18 column (5 µm, 150 × 2.0 mm) and a mobile phase consisting of 70 % of mobile phase A (10 mM of ammonium acetate and 1% formic acid in purified water) and 30 % mobile phase B (0.1 % formic acid in acetonitrile) at a flow rate of 500 µl/min on an isocratic program. Both the analyte and the internal standard were quantified using the positive electrospray ionization (ESI) mode within a single runtime of 5.00 min. The method was validated following the U.S. Food and Drug Administration guidelines over the concentration range of 3-1000 µg/mL. The within-run and between-run precision and accuracy were <15 %, and therefore met the standard regulatory acceptance criterion. In conclusion, a sensitive and robust LC-MS/MS method was developed for a fast quantitation of ceftriaxone concentrations in plasma samples with multiples applications in research and clinical therapeutic drug monitoring.

Ampicillin and Ceftriaxone Solution Stability at Different Temperatures in Outpatient Parenteral Antimicrobial Therapy.

The inclusion of ampicillin-containing regimens in outpatient parenteral antimicrobial therapy programs (OPAT) depends upon solution stability under conditions similar to those experienced in these programs. Lack of this information could hinder the inclusion in OPAT of patients suffering from Enterococcus faecalis infective endocarditis treated with ampicillin plus ceftriaxone. The purpose of this study is to determine the stability of ampicillin and ampicillin plus ceftriaxone solutions in a simulated outpatient setting conditions. Solutions of ampicillin 24 g/liter and ampicillin 24 g/liter combined with ceftriaxone 8 g/liter were stored at 25°C ± 2°C, 30°C ± 2°C and 37°C ± 2°C for 48 h. Chemical and physical stability were evaluated at 20, 24, 30, and 48 h after manufacturing. The solutions were considered stable if the percentage of intact drug was ≥90% and color and clearness remained unchanged. After 24 h of storage at a controlled temperature, ampicillin solution in 0.9% sodium chloride was found to be stable for 30 h at 25 and 30°C and for 24 h at 37°C. In the ampicillin plus ceftriaxone combined solution, both antibiotics were found to be stable after 30 h of storage at 25 and 30°C, but at 37°C, the stability criterion was not met at any time point. Our study offers solid evidence demonstrating that the concentrations of both drugs at two of the tested temperatures (25°C and 30°C) were stable for up to 30 h. Therefore, both ampicillin alone and ampicillin plus ceftriaxone solutions would be appropriate candidates for inclusion in OPAT programs.

Outcomes of the PIRASOA programme, an antimicrobial stewardship programme implemented in hospitals of the Public Health System of Andalusia, Spain: an ecologic study of time-trend analysis.

OBJECTIVES: Inappropriate antimicrobial use favours the spread of resistance, and multidrug-resistant microorganisms (MDR) are currently of major concern. Antimicrobial stewardship programmes (ASPs) are essential for improving antibiotic use in hospitals. However, their impact on entire healthcare systems has not been thoroughly assessed. Our objective was to provide the results of an institutionally supported ASP involving 31 public hospitals in Andalusia, Spain. METHODS: We designed an ecologic time-series study from 1 January 2014 to 31 December 2017. Quarterly, data on indicators were collected prospectively, and feedback reports were provided. PIRASOA is an ongoing clinically based quality-improvement programme whose key intervention is the educational interview, regular peer-to-peer interventions between advisors and prescribers to reinforce the appropriate use of antibiotics. Seventy-two indicators were monitored to measure prescribing quality (inappropriate treatments), antimicrobial consumption (defined daily doses per 1000 occupied bed-days), incidence density of MDR per 1000 occupied bed-days and crude mortality rate associated with bloodstream infections. We used Joinpoint regression software to analyse the trends. RESULTS: The quality of antimicrobial prescribing improved markedly, and the inappropriate treatment rate was significantly lower, with quarterly percentage change (QPC) = -3.0%, p < 0.001. Total antimicrobial consumption decreased (QPC = -0.9%, p < 0.001), specifically carbapenems, amoxicillin/clavulanic acid, quinolones and antifungal agents, whereas antipseudomonal cephalosporin use increased. While the incidence of MDR showed a sustained decreasing trend (QPC = -1.8%; p 0.002), the mortality of patients with bloodstream infections remained stable (QPC = -0.2%, p 0.605). CONCLUSIONS: To date, the PIRASOA programme has succeeded in optimizing the use of antimicrobial agents and has had a positive ecologic result on bacterial resistance at level of an entire healthcare system.

A multimodal intervention program to control a long-term Acinetobacter baumannii endemic in a tertiary care hospital.

Background: Acinetobacter baumannii causes frequently nosocomial infections worldwide. Its ability to survive on dry surfaces facilitates its spread and the persistence of endemic situations, especially in the intensive care units (ICUs).The objective of this paper is to describe a multicomponent intervention program designed to control a hyperendemic persistence of multidrug-resistant A. baumannii (MDR-Ab) and to characterize its impact. Methods: Design: Quasi-experimental intervention study based on open cohorts.Setting: Public tertiary referral centre. Period: January 2009-August 2017.Intervention: multifaceted program based on environmental decontamination, hand hygiene, antimicrobial stewardship, contact precautions, active surveillance, weekly reports and regular meetings.Analysis: joinpoint regression and interrupted time-series analysis. Results: The intervention was successfully implemented. Through the study period, the compliance with contact precautions changed from 0 to 100% and with hand hygiene, from 41.8 to 82.3%. Between 2012 and 2016, the antibiotic consumption decreased from 165.35 in to 150.44 daily-defined doses/1000 patients-days in the ICU. The incidence density of MDR-Ab in the ICU was 10.9 cases/1000 patients-days at the beginning of the intervention. After this moment, the evolution of the incidence density of MDR-Ab was: between months 0 and 6°, it remained stable; between months 7° and 10°: there was an intense decrease, with an average monthly percentage change (AMPC) = - 30.05%; from 11° month until the end, the decrease was lighter but continuous (AMPC:-2.77%), achieving an incidence density of 0 cases/1000 patients-days on the 18° month, without any new case for 12 months. From the 30° month until the end of the study period, several little outbreaks of MDR-Ab were detected, all of them rapidly controlled. The strains of MDR-Ab isolated during these outbreaks were not clonally related with the previously endemic one, which supports its eradication from the environmental reservoirs. Conclusion: The multicomponent intervention performed by a multidisciplinary team was effective to eradicate the endemic MDR-Ab.

Outpatient parenteral antimicrobial therapy in Enterococcus faecalis infective endocarditis.

WHAT IS KNOWN AND OBJECTIVE: Enterococcus faecalis is the third most common causal agent of infective endocarditis. Currently, the treatment recommended is a combination of ampicillin (2 g/4 h) plus ceftriaxone (2 g/12 h), so patients must remain hospitalized for almost 6 weeks to receive the treatment. They are not generally included in outpatient parenteral antimicrobial therapy programs because 2 different electronic pumps are required to administer these 2 antibiotics. To enable the treatment of patients with E. faecalis IE at home, we designed a continuation combination regimen of ceftriaxone 4 g once daily in a short infusion plus ampicillin 2 g/4 h using a programmable pump. METHODS: We analyzed a cohort of patients attended in an outpatient parenteral antimicrobial therapy program that has been working since 2012 in 2 tertiary hospitals. We selected patients attended in this program for E. faecalis IE treated with a continuation regimen of ampicillin 12 g daily (2 g/4 h) and ceftriaxone 4 g every 24 hours between July 2012 and March 2017. RESULTS AND DISCUSSION: Of the 720 patients included in the outpatient parenteral antimicrobial therapy program, 42 had infective endocarditis, and 4 (9.52%) were treated using the combination regimen described above. All patients were men, and all had left-sided native-valve infective endocarditis. All 4 patients received ampicillin 2 g every 4 hours and ceftriaxone 2 g every 12 hours in hospital, for a median duration of 25 days (IQR 15-32). Thereafter, in the program, they received the following regimen: a 30-minute infusion of ceftriaxone 4 g in 250 mL of saline solution, followed by ampicillin 12 g daily in 500 mL of saline solution delivered by a pump programmed to administer 2 g every 4 hours. Patients received this treatment at home for a median of 22.5 days (IQR 13-32). All patients achieved clinical and microbiological cure with no recurrences or complications after a lengthy follow-up period (median 365 days, IQR 221-406). No drug-related adverse events or problems with the pump system were reported. WHAT IS NEW AND CONCLUSIONS: Use of ceftriaxone 4 g in a single dose yields a mean plasma concentration of 30 µg/mL. Ceftriaxone also has a high plasma protein binding capability, and once this binding is saturated, there is no reason to administer higher doses. Therefore, it seems reasonable to use a dose of 4 g of ceftriaxone once daily to have a synergist effect with ampicillin within the vegetation, and enable the treatment of patients with E. faecalis infective endocarditis at home. In conclusion, the administration of ampicillin (2 g/4 h) plus ceftriaxone (4 g/24 h) as a continuation regimen in an outpatient parenteral antimicrobial therapy program may be as effective and safe as the usual lengthy in-hospital regimen (ampicillin 2 g/4 h and ceftriaxone 2 g/12 h) in patients with E. faecalis infective endocarditis.

Sequential antimicrobial treatment with linezolid for neurosurgical infections: efficacy, safety and cost study.

BACKGROUND: Evidence for the effectiveness of linezolid in neurosurgical infections (NSIs) is growing. The comfortable oral dosage and tolerance of linezolid opens the possibility for sequential antimicrobial treatment (SAT) in stable patients after a period of intravenous treatment. METHODS: To evaluate the efficacy and safety of SAT with oral linezolid in patients with NSI and to analyse the cost implications, an observational, non-comparative, prospective cohort study was conducted on clinically stable consecutive adult patients at the Neurosurgical Service. Following intravenous treatment, patients were discharged with SAT with oral linezolid. RESULTS: A total of 77 patients were included. The most common NSIs were: 41 surgical wound infections, 20 subdural empyemas, 18 epidural abscesses, and 16 brain abscesses. Forty-four percent of patients presented two or more concomitant NSIs. Aetiological agents commonly isolated were: Propionibacterium acnes (36 %), Staphylococcus aureus (23 %), Staphylococcus epidermidis (21 %) and Streptococcus spp. (13 %). The median duration of the SAT was 15 days (range, 3-42). The SAT was interrupted in five cases due to adverse events. The remainder of the patients were cured at the end of the SAT. A total of 1,163 days of hospitalisation were saved. An overall cost reduction of €516,188 was attributed to the SAT. Eight patients with device infections did not require removal of the device, with an additional cost reduction of €190,595. The mean cost saving per patient was €9,179. CONCLUSIONS: SAT with linezolid was safe and effective for the treatment of NSI. SAT reduces hospitalisation times, which means significant savings of health and economic resources.

[Failure mode effect analysis applied to preparation of intravenous cytostatics]. / Análisis modal de fallos y efectos aplicado a la elaboración de citostáticos intravenosos.

OBJECTIVE: To proactively identify risks in the preparation of intravenous cytostatic drugs, and to prioritise and establish measures to improve safety procedures. MATERIAL AND METHODS: Failure Mode Effect Analysis methodology was used. A multidisciplinary team identified potential failure modes of the procedure through a brainstorming session. The impact associated with each failure mode was assessed with the Risk Priority Number (RPN), which involves three variables: occurrence, severity, and detectability. Improvement measures were established for all identified failure modes, with those with RPN>100 considered critical. The final RPN (theoretical) that would result from the proposed measures was also calculated and the process was redesigned. RESULTS: A total of 34 failure modes were identified. The initial accumulated RPN was 3022 (range: 3-252), and after recommended actions the final RPN was 1292 (range: 3-189). RPN scores >100 were obtained in 13 failure modes; only the dispensing sub-process was free of critical points (RPN>100). A final reduction of RPN>50% was achieved in 9 failure modes. CONCLUSIONS: This prospective risk analysis methodology allows the weaknesses of the procedure to be prioritised, optimize use of resources, and a substantial improvement in the safety of the preparation of cytostatic drugs through the introduction of double checking and intermediate product labelling.

Política de antibióticos. Comisión de Infecciones y uso de antimicrobianos / The antibiotic policy. The Infection Committee and antimicrobial use

La política de antibióticos es el conjunto de estrategias y actividades llevadas a cabo para organizar el tratamiento antimicrobiano en el hospital, y conseguir resultados en salud para los pacientes. Los principios básicos que deben dirigirla son la medicina basada en la evidencia, la epidemiología local y la libertad de prescripción de los facultativos. En la actualidad, la política de antibióticos es más necesaria que nunca por razones clínicas, epidemiológicas y económicas. La Comisión de Infecciones es la responsable de la política de antibióticos en los hospitales. Sus funciones, como órgano asesor de la dirección médica, son el análisis de la epidemiología de las infecciones del centro, las medidas para su prevención y control, la mejora del uso apropiado de los antimicrobianos, la formación y la producción de conocimientos. Conseguir los objetivos clínicos, ecológicos y económicos de la política de antibióticos no es tarea fácil. Poner de acuerdo a cientos de profesionales en torno a las recomendaciones sobre indicaciones, posología y duración del tratamiento antibiótico basadas en las mejores evidencias científicas y en las guías locales, es complejo, pero se puede hacer. Para ello es clave que la Comisión de Infecciones desarrolle el PROA a través de un equipo multidisciplinar y con liderazgo profesional, y que cuente con el apoyo institucional que asegure que el buen uso de los antimicrobianos es un objetivo prioritario del centro, y por lo tanto de cada uno de los servicios implicados, y que el equipo de PROA dispone de los recursos necesarios (AU)

The antibiotic policy is the set of strategies and activities undertaken to organize the antimicrobial treatment in the hospital, and achieve health outcomes for patients. The basic principles are to be direct evidence-based medicine, local epidemiology and freedom for prescribing physicians. Anantibiotic policy is now more necessary than ever for clinical, epidemiological and economic reasons. The Infection Committee is responsible for the antibiotics policy in hospitals. Its functions as an advisory body to the medical directorate are the analysis of the epidemiology of the infections in the center, measures for its prevention and control, improving the appropriate use of antimicrobials, training, and knowledge production. To achieve clinical, environmental and economic policy objectives of antibiotics is not easy. The agreement of hundreds of professionals for recommendations on indications, dosage and duration of antibiotic treatment, based on the best scientific evidence and local guides is complex, but it can be done. The key to this is that the Infection Committee develops antimicrobial stewardship through a multidisciplinary team and professional leadership, and has the institutional support to ensure that the proper use of antimicrobials is a priority for the center, and therefore of each of the services involved, and that the team has the resources for antimicrobial stewardship (AU)

[The antibiotic policy. The Infection Committee and antimicrobial use]. / Política de antibióticos. Comisión de Infecciones y uso de antimicrobianos.

The antibiotic policy is the set of strategies and activities undertaken to organize the antimicrobial treatment in the hospital, and achieve health outcomes for patients. The basic principles are to be direct evidence-based medicine, local epidemiology and freedom for prescribing physicians. An antibiotic policy is now more necessary than ever for clinical, epidemiological and economic reasons. The Infection Committee is responsible for the antibiotics policy in hospitals. Its functions as an advisory body to the medical directorate are the analysis of the epidemiology of the infections in the center, measures for its prevention and control, improving the appropriate use of antimicrobials, training, and knowledge production. To achieve clinical, environmental and economic policy objectives of antibiotics is not easy. The agreement of hundreds of professionals for recommendations on indications, dosage and duration of antibiotic treatment, based on the best scientific evidence and local guides is complex, but it can be done. The key to this is that the Infection Committee develops antimicrobial stewardship through a multidisciplinary team and professional leadership, and has the institutional support to ensure that the proper use of antimicrobials is a priority for the center, and therefore of each of the services involved, and that the team has the resources for antimicrobial stewardship.

Global impact of an educational antimicrobial stewardship programme on prescribing practice in a tertiary hospital centre.

The misuse of antibiotics has been related to increased morbidity, mortality and bacterial resistance. The development of antimicrobial stewardship programmes (ASPs) has been encouraged by scientific societies as an essential measure. An educational, institutionally supported ASP was developed in our tertiary-care centre. Local guidelines on the management of infectious syndromes were created. Antimicrobial prescriptions were chosen arbitrarily weekly and counselling interviews by expert clinicians were carried out, using a paedagogic, non-restrictive methodology. Satisfaction with the interview was assessed using anonymous questionnaires. The appropriateness of antimicrobial prescriptions as well as consumption was assessed prospectively throughout the year. Feedback regarding the correct use of treatments was communicated to each participating department periodically. The improvement in antimicrobial prescription was included among the annual objectives linked to economic incentives in every department. A total of 1206 counselling interviews were carried out during the first year. Fifty-three per cent of antimicrobial prescriptions (176/332) were inappropriate when the programme started. The rate of inappropriate prescriptions continuously declined to 26.4% (107/405) in the fourth trimester (p <0.001; RR = 0.38; 95% CI, 0.23-0.43). Antimicrobial consumption decreased from 1150 defined daily doses (DDDs) per 1000 occupied bed-days in the first trimester to 852 DDDs in the fourth, reflecting a reduction in antimicrobial expenditures of 42%. A total of 352 satisfaction questionnaires were received and 98% described the advice as positive. In conclusion, the implementation of an education-based ASP achieved a significant improvement in all antimicrobial prescriptions in the centre and a reduction in antimicrobial consumption, even when no restrictive measures were implemented. The programme was highly accepted by all prescribers.

Cost-effectiveness analysis comparing two approaches for empirical antifungal therapy in hematological patients with persistent febrile neutropenia.

New approaches of empirical antifungal therapy (EAT) in selected hematological patients with persistent febrile neutropenia (PFN) have been proposed in recent years, but their cost-effectiveness has not been studied. The aim of this study was to compare the cost-effectiveness of two different approaches of EAT in hematological patients with PFN: the diagnosis-driven antifungal therapy (DDAT) approach versus the standard approach of EAT. A decision tree to assess the cost-effectiveness of both approaches was developed. Outcome probabilities and treatment pathways were extrapolated from two studies: a prospective cohort study following the DDAT approach and a randomized clinical trial following the standard approach. Uncertainty was undertaken through sensitivity analyses and Monte Carlo simulation. The average effectiveness and economic advantages in the DDAT approach compared to the standard approach were 2.6% and €5,879 (33%) per PFN episode, respectively. The DDAT was the dominant approach in the 99.5% of the simulations performed with average cost-effectiveness per PFN episode of €32,671 versus €52,479 in the EAT approach. The results were robust over a wide range of variables. The DDAT approach is more cost-effective than the EAT approach in the management of PFN in hematological patients.

Piperacilina-tazobactam en perfusión continua o expandida frente a perfusión intermitente / Piperacillin-tazobactam in continuous or expanded perfusion vs intermittent perfusion

Objetivo: El objetivo principal de esta revisión es analizar las diferencias de eficacia entre la administración en perfusión intermitente y la administración en perfusión continua/expandida de piperacilina-tazobactam. Como objetivos secundarios se analizan las diferencias en seguridad, parámetros farmacocinéticos/farmacodinámicos y coste-efectividad entre las 2 formas de administración. Método Se realizaron 2 búsquedas bibliográficas independientes. Se encontraron un total de 38 artículos y finalmente se incluyeron en el estudio 6. Se analizaron los artículos incluidos y se recogieron las variables diseño, tratamiento administrado a cada grupo, número de pacientes total y perteneciente a cada grupo, variables recogidas en cada estudio y resultados. Resultados Se hallaron diferencias significativas en la variable principal en 2 de los 6 estudios incluidos a favor de la perfusión continua/expandida. En el estudio de Lodise et al. se encontraron diferencias (p = 0,04) en mortalidad (31,6% en perfusión intermitente vs 12,2% en perfusión continua/expandida). En el estudio de Lorente et al. se encontraron diferencias (p = 0,001) en curación clínica (56,5% perfusión intermitente vs 89,2% en perfusión continua/expandida). En cuanto a las variables secundarias solo se encontraron diferencias en uno de los estudios en la relación coste-efectividad a favor del grupo de perfusión continua/expandida. Conclusión Los datos analizados indican que la perfusión continua/expandida sería al menos igual de eficaz que la perfusión intermitente, y que podría ser más eficaz en pacientes más graves, o con infecciones por microorganismos más resistentes, como Pseudomonas aeruginosa. Además esta forma de administración es, en teoría, más coste-efectiva (AU)

Objective: The primary objective of this review was to analyse the differences in efficacy between the administration of intermittent and continuous/expanded perfusion of piperacillin-tazobactam. Secondary objectives were to analyse the differences in safety, pharmacokinetic/pharmacodynamic parameters, and cost-effectiveness between the two forms of administration. Method: We performed two different independent bibliographic searches. We encountered a total of 38 articles, and the final number included in the study was 6. We analysed the articles and collected the following variables: design, treatment administered to each group, total number of patients and number of patients in each study, variables collected in each study, and results. Results: We encountered significant differences in the primary variable in two of the six studies favouring continuous/expanded perfusion. The study by Lodise et al found differences (P=.04)in mortality (31.6% for intermittent perfusion vs 12.2% for continuous/expanded perfusion).The study by Lorente et al found differences (P=.001) in terms of clinical recovery (56.5% for intermittent perfusion vs 89.2% for continuous/expanded perfusion). As for secondary variables, we only found differences in one of the studies in relation to cost-effectiveness, in favour of the group who underwent continuous/expanded perfusion method. Conclusion: The analysed data suggest that continuous/expanded perfusion would be at least as effective as intermittent perfusion, and that it could be more effective in severe patients with infections from more resistant micro-organisms such as Pseudomonas aeruginosa. Additionally, this form of administration is more cost-effective, at least in theory (AU)

[Piperacillin-tazobactam in continuous or expanded perfusion vs intermittent perfusion]. / Piperacilina-tazobactam en perfusión continua o expandida frente a perfusión intermitente.

OBJECTIVE: The primary objective of this review was to analyse the differences in efficacy between the administration of intermittent and continuous/expanded perfusion of piperacillin-tazobactam. Secondary objectives were to analyse the differences in safety, pharmacokinetic/pharmacodynamic parameters, and cost-effectiveness between the two forms of administration. METHOD: We performed two different independent bibliographic searches. We encountered a total of 38 articles, and the final number included in the study was 6. We analysed the articles and collected the following variables: design, treatment administered to each group, total number of patients and number of patients in each study, variables collected in each study, and results. RESULTS: We encountered significant differences in the primary variable in two of the six studies favouring continuous/expanded perfusion. The study by Lodise et al found differences (P=.04) in mortality (31.6% for intermittent perfusion vs 12.2% for continuous/expanded perfusion). The study by Lorente et al found differences (P=.001) in terms of clinical recovery (56.5% for intermittent perfusion vs 89.2% for continuous/expanded perfusion). As for secondary variables, we only found differences in one of the studies in relation to cost-effectiveness, in favour of the group who underwent continuous/expanded perfusion method. CONCLUSION: The analysed data suggest that continuous/expanded perfusion would be at least as effective as intermittent perfusion, and that it could be more effective in severe patients with infections from more resistant micro-organisms such as Pseudomonas aeruginosa. Additionally, this form of administration is more cost-effective, at least in theory.

Abscesos piógenos y tuberculosos del músculo psoas / Pyogenic and tuberculous abscesses of the psoas muscle

Objetivos. Precisar las características clínicas de los pacientes con absceso del músculo psoas (AP) y las posibles diferencias existentes entre los AP piógenos o tuberculosos. Pacientes y métodos. Revisión retrospectiva de los pacientes diagnosticados de AP en un hospital (1983-2009). Se establecieron dos grupos, piógenos y tuberculosos, y se compararon sus hallazgos clínicos, analíticos y evolución. Resultados. Se incluyeron 30 pacientes con AP, 25 piógenos y 5 tuberculosos, En 9 ocasiones fueron primarios y en 21 secundarios (a patología esquelética en 8 a patología urológica en 8 y a gastrointestinal en 8). No se observaron diferencias clínicas entre ambos grupos. Los pacientes con AP piógenos tendieron a tener mayores cifras de leucocitos (13.871 vs. 8.560/mm3, p=0,018) y de velocidad de sedimentación globular (VSG) (108 vs. 17mm/h, p<0,0001) y menores de hemoglobina (11 vs. 14g/dL, p=0,008) Se diagnosticaron por tomografía computarizada (TC) en 29 pacientes y por resonancia magnética en 1, ambas con una sensibilidad diagnóstica del 100%, frente al 50% de la ecografía. La lateralidad izquierda fue menos frecuente en los AP piógenos (44 vs. 100%, p=0,031). Los hemocultivos y el cultivo de pus del absceso fueron positivos en el 22% y 82% de las ocasiones en las que se realizó. Los gérmenes aislados con más frecuencia fueron bacilos gramnegativos, Streptococcus spp. y S. aureus. El 50% de los casos fueron drenados percutáneamente, el 13% quirúrgicamente y el 3% por ambas técnicas. Fallecieron 2 pacientes, ambos con absceso piógeno. Conclusiones. Los abscesos piógenos secundarios constituyen el grupo de AP más frecuente. La TC es el procedimiento diagnóstico de elección. La presencia de leucocitosis, anemia, VSG elevada y la lateralidad derecha sugieren etiología piógena. El drenaje percutáneo está sustituyendo al quirúrgico y permite obtener muestras diagnósticas(AU)

Objectives. To describe the clinical characteristics of patients with abscess on the psoas muscle (PA) and to identify the possible differences existing between pyogenic and tuberculous etiologies. Patients and methods. A retrospective review of patients diagnosed of PA in one hospital was conducted (1983-2009). Two groups were established, that is pyogenic and tuberculous, and the clinical findings, analyses and evolution were compared. Results. Thirty PA were included, 83% pyogenic and 17% tuberculous, average age 53 years. On 9 occasions, 30% were primary and on 21 occasions, 70% secondary (to skeletal pathology in 8, to urological in 8 and to gastrointestinal in 8). No clinical differences were observed between both groups. Pyogenic and tuberculous etiologies were differentiated analytically through leukocyte values (13,871 vs. 8,560/mm3, p=0.018), hemoglobin (11 vs. 14g/dL, p=0.008) and erythrocyte sedimentation rate (ESR) (108 vs. 17mm/h, p<0.0001). Abscesses were diagnosed by computed tomography (CT) in 29 patients (97%) and by magnetic resonance in 1 (3%), both with a diagnostic sensitivity of 100%, as opposed to 50% for ultrasound scanning. Left laterality was less frequent in pyogenic abscesses (44% vs. 100%, p=0.031). The blood cultures were positive in 22% and abscess pus culture in 82%. Gram negative bacilli, Streptococcus spp. and S. aureus were the most frequent isolations. A total of 67% were drained: transcutaneously 50%, surgically 13% and both techniques 3%. Two patients died (7%), both with pyogenic abscess. Conclusions. Secondary pyogenic abscesses constitute the most frequent PA group. CT is the diagnostic procedure of choice. Leukocytosis, anemia, raised ESR and right laterality suggest pyogenic etiology. Transcutaneous drainage is substituting surgical drainage and also makes it possible to obtain diagnostic samples(AU)