[Invasive Streptococcus pyogenes diseases 2005-2013: Pediatric Hospital Pereira Rossell Uruguay]. / Enfermedades invasoras por Streptococcus pyogenes 2005-2013: Hospital Pediátrico del Centro Hospitalario Pereira Rossell, Uruguay.

INTRODUCTION: Streptococcus pyogenes infection causes a wide spectrum of clinical manifestations. Invasive disease (ID) is defined by the isolation of the microorganism from sterile sites. OBJECTIVE: To analyze the clinical, epidemiological and molecular characteristics of ID by S.pyogenes in children hospitalized at Pediatric Hospital Pereira Rossell, from January 2005 to January 2013. MATERIALS AND METHODS: A descriptive retrospective study was done in cases with isolation of S.pyogenes from sterile sites. Epidemiological variables, disease characteristics, laboratory parameters, treatment regimen received, hospitalization days and clinical outcome were analyzed. The presence of 4 genes encoding for virulence factors and chromosome profile studied by pulsed-field electrophoresis were done in the isolated strains. RESULTS: A total of 42 cases (rate: 4.6 out of 10,000 admissions) were detected, from which 32 were analyzed. Average age was 44.7 months (14/32 < 2 years of age). In 5 cases, the portal of entry was identified. Clinical presentations were: osteoarticular infections (n = 15), shock (n = 6), skin and soft-tissue infections (n = 5), pneumonia (n = 3) and bacteremias (n = 3). Twenty cases required surgical procedures and 13 required intensive care admission. Average hospital stay was 17 days and one patient died. Molecular studies were performed in five strains; 4 different toxin profiles and pulsotypes were identified. DISCUSSION: The incidence of ID at our hospital is similar to other series in the region. A better knowledge of clinical presentation and its relation with molecular characteristics represents a challenge.

Identification of cell culture contamination by an unusual species of Mycoplasma related to the M. mycoides cluster.

Mycoplasma contamination is a significant problem in cell culture replication and maintenance. From more than 200 known species, a limited number of Mycoplasma species have been detected in cell cultures, representing new species or variants that can escape detection systems. A qPCR commercial kit was used for Mycoplasma detection in cell cultures. Furthermore, an amplified Mycoplasma species was sequenced and summited for sequence assembly, clustering, and evolutionary analysis study. Our work has identified a new and unusual variant or species of Mycoplasma that possesses a high degree of homology with species related with M. mycoides cluster. This variant is usually associated with cattle but has been detected contaminating a cell culture. Mycoplasma testing (even for unusual species) in cell cultures is essential to ensure the validity and reproducibility of research that uses cell cultures and to ensure the quality of cell line deposits in biobanks. For this reason, it is necessary to perform continuous checks for the absence of Mycoplasma in cell cultures and engage in the continuous adaptation of relevant detection systems.

[Antibiotic consumption and antimicrobial susceptibility evolution in the Centro Hospitalario Pereira Rossell in methicillin resistant Staphylococcus aureus era]. / Evolución del consumo de antibióticos y de la susceptibilidad antimicrobiana en el Centro Hospitalario Pereira Rossell en la era de Staphylococcus aureus resistente a meticilina.

INTRODUCTION: In the past few years, an increase in methicillin resistant-not multiresistant Staphylococcus aureus was observed in Uruguay among children with community acquired infections. Recommendations for empiric antibiotic treatment required adjustments and new national guidelines were recommended in July 2004. Adherence to these guidelines was indirectly performed by monitoring antibiotic consumption and antimicrobial susceptibility patterns in Uruguay. OBJECTIVE: To describe and compare antibiotic consumption and antimicrobial susceptibility of Staphylococcus aureus in a Pediatric Hospital of the Centro Hospitalario Pereira Rossell (PH-CHPR) between 2001 and 2006. METHODS: Antibiotic consumption in hospitalized children was calculated using the Defined Daily Dose per 100 bed-days (DDD/100). Reference values were obtained from the World Health Organization Collaborating Center for Drug Statistics Methodology of. Consumption. Data were obtained using the WinPharma programme of the Pharmacy Department of CHPR. The fraction of annual occupancy of hospital beds was obtained from the Statistic Division of CHPR. Antibiotic consumption was evaluated between 2001 and 2006 and expressed as DDD/100 and percent change. Antimicrobial susceptibility was evaluated using CHPR's Microbiology Laboratory data during the same time period. RESULTS: After 2003 a significant increase in consumption of clindamycin, ceftriaxone, trimethoprim-sulphamethoxazole, cefuroxime, vancomycin and gentamycin was observed, except for cephradine. Consumption of clindamycin, ceftriaxone and trimethoprim-sulphamethoxazole showed the highest increase (6.15%; 1.44% and 1.17% respectively). Detection of Staphylococcus aureus increased significantly mostly from skin and soft tissue infections. Oxacillin susceptibility of S. aureus strains obtained from different sites had a significant and persistent decrease after 2003 (from 81 % during year 2001 to 40% in year 2006 (p < 0.05). Susceptibility to others antibiotics did not decrease. Between 2004 and 2006 the "D effect" decreased from 28% to 21 %. Antimicrobial susceptibility patterns did not differ by site of infection. CONCLUSIONS: Methicillin resistant-not multiresistant Staphylococcus aureus has established itself as a regular community pathogen in Uruguayan children. Changes in antimicrobial consumption patterns reflect the impact of this pathogen in clinical practice and the overall adherence to new recommendations. This change was not associated with an increase in antibiotic resistance. Clindamycin is an alternative treatment although Clindamycin inducible resistance is a worry. Continuous monitoring of antibiotic consumption and local susceptibility patterns are required to promote rational use of antibiotics.

[Etiology and evolution of the osteoarticular infections. 2009-2015: Pediatric Hospital Pereira Rossell Uruguay]. / Etiología y evolución de las infecciones osteo-articulares 2009-2015: Hospital Pediátrico del Centro Hospitalario Pereira Rossell, Uruguay.

BACKGROUND: The most frequent osteoarticular infections (OAI) etiological agent is Staphylococcus aureus. The prevalence of other microorganisms has changed after the introduction of new vaccines. AIM: To describe the etiology and evolution of the OAIs in children hospitalized in Pediatric Hospital Pereira Rossell between 2009 and 2015. PATIENTS AND METHODS: Joint fluid and bone puncture studies of hospitalized children suspected of OAI. Epidemiological characteristics, isolated microorganisms, complementary tests, initial treatment, complications, and days of hospitalization were analyzed. RESULTS: 335 patients; the etiology was established in 113. Clinical data could be analyzed in 87 cases. The average age was 6.1 years. They corresponded to: methicillin-sensitive S. aureus (n: 47), community-acquired methicillin-resistant S. aureus (CA-MRSA) (n: 11), Streptococcus pyogenes (n: 6), Streptococcus pneumoniae (n: 1), Haemophilus influenzae type b (n: 2), Gram-negative bacilli (n: 9), Kingella kingae (n: 1) others (n: 6). In 4 cases, more than one microorganism was isolated. CA-MRSA infections were more serious. DISCUSSION: A decrease is observed in the number of CA-MRSA isolates. A fact to be highlighted is the impact of universal vaccination against S. pneumoniae and H. influenzae type b. It is a finding to be monitored the increasing number of Gram-negative bacilli isolates.

[A five-year experience with zoonotic Salmonella at a pediatric reference centre]. / Un quinquenio de experiencia (2005-2010) con infecciones por Salmonella spp en un centro nacional de referencia en pediatría.

BACKGROUND: Salmonella can cause asymptomatic infections, diarrhea, bacteremia and focal infections such as meningitis and osteomyelitis. AIM: To describe clinical and microbiological aspects of infections by Salmonella spp. in children in a pediatric referral hospital: Centro Hospitalario Pereira Rossell, in Montevideo, Uruguay. MATERIALS AND METHODS: Descriptive and retrospective study of 46 patients, from which Salmonella spp was isolated between January 1, 2005 and December 31, 2010. RESULTS: Salmonella spp was isolated in 46 children younger than 15 years old. 18 were below 2 years old and 5 children below three months. 24% of the children had risk factors, such as HIV infection, oncological diseases and malnutrition; low birth weight and pneumonia were associated conditions. No deaths were reported. The serotypes more frequently found were: Typhimurium and Enteritidis. Most of the strains were susceptible to ampicillin and third generation of cephalosporins. DISCUSSION: Diarrhea with blood was the predominant clinical presentation, and there were no outbreaks. Typhimurium and Enteritidis were the most common serotypes. Based on the profiles of susceptibility antimicrobial, we could maintain the same recommendations until the moment suggested. CONCLUSIONS: we must consider the Salmonella infection in febrile children under risk of an invasive bacterial disease, with or without focal infection.

Use of specific antibody and circulating antigen serum levels in the hydatid immunodiagnosis of asymptomatic population.

Levels of specific antibodies (Ab) and circulating antigens (CAg) were tested by ELISA in sera from 115 surgically confirmed hydatid patients, 41 individuals exhibiting other parasitic and unrelated diseases and 69 healthy subjects. Addition of CAg data to Ab detection in this sera collection increased sensitivity from 85% (only Ab) to 89% (Ab + CAg). Combination of ultrasonography with Ab and CAg serology for diagnosis of asymptomatic population in endemic areas was analyzed. One field survey (163 persons) involved both blood extraction and ultrasonography to all the population. Three people exhibited cyst images and all of them were Ab positive, while 6 Ab and 1 CAg positive individuals exhibited no cyst image. Another survey (1620 persons) involved a selection of 85 subjects for serology according to ultrasound data and record of family hydatid history. Twelve per cent exhibited no hydatid image being serologically positive and 14% were serologically negative but exhibited cyst image. Ultrasonography and serology (Ab and CAg) should be used in combination to maximize the diagnostic yield in asymptomatic population.

Standard case management of pneumonia in hospitalized children in Uruguay, 1997 to 1998.

OBJECTIVE: To report the results of the use of antimicrobial guidelines for the management of children with community-acquired bacterial pneumonia. METHODS: Admittance and discharge criteria and algorithms for diagnosis and treatment were established. The decision to treat with antibiotics was based on radiologic findings in pneumonia with pulmonary consolidation and left to the attending physician's criteria in the remaining cases. The use of antibiotics was limited to penicillin and derivatives (ampicillin, amoxicillin) and macrolides. RESULTS: Of the 1163 children treated as bacterial pneumonia, hospitalized in public and private health facilities in Montevideo from September, 1997, through September, 1998, standard case management was applied in 1082 (93%). Age distribution was: <1 month, 1%; between 1 and 11 months, 29%; between 1 and 5 years, 50%; >5 years, 20%. Chest radiography showed evidence of pulmonary consolidation in 843 children (73%). Bacteria were detected in blood culture and/or pleural fluid of 57 children (5%). In 51 the identified microorganism was Streptococcus pneumoniae, susceptible to penicillin in 30, intermediate in 6 and resistant in 5 (maximum MIC, 4 microg/ml); in 10 cases etiologic diagnosis was made by antigen detection. Empyema was present in 62 children (5.3%); 38 (3.27%) required treatment in an intensive care unit; and 5 (0.4%) died. CONCLUSIONS: Compliance with standard case management was highly satisfactory. Outcome of children treated with penicillin and derivatives was good, including children with empyema and pneumatocele and two patients with penicillin-resistant S. pneumoniae. At the present time S. pneumoniae resistant to penicillin is not an important problem in children with pneumonia in Uruguay. Surveillance of identified microorganisms and their antimicrobial susceptibility must continue.

Screening of dioxin-like compounds by complementary evaluation strategy utilising ELISA, micro-EROD, and HRGC-HRMS in soil and sediments from Montevideo, Uruguay.

Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are persistent, toxic, and bioaccumulate in the environment. Due to their high analytical costs, these compounds are hardly regulated and mostly not monitored in the Third World. To overcome this, bioassays have been proposed as low-cost alternative methods. Two of the most established bioanalytical tools, the dioxin antibody-based enzyme-linked immunosorbent assay ELISA and the micro-EROD bioassay are evaluated and compared to high resolution gas chromatography and high resolution mass spectrometry (HRGC/HRMS) analytical methodology. The methods were tested using thirteen soils and sediment samples selected from diverse sites in Montevideo, Uruguay. The WHO2005 total toxic equivalent (WHO2005-TEQ) of soils ranged from 2.4 to 2212 (ng WHO2005-TEQ/kg dry sample) and from 0.14 to 9.4 (ng WHO2005-TEQ/kg dry sample) in sediments. This study shows significant contamination related to dioxin-like compounds, particularly in sites where uncontrolled burnings were carried out. ELISA and micro-EROD bioassay correlated well with HRGC/HRMS, R Spearman 0.773 and 0.913, respectively and were highly correlated to each other, R Spearman 0.879. Preliminary threshold values of bioassay toxic equivalents of 330 (ng/kg dry sample) for the micro-EROD bioassay and 220 (ng/kg dry sample) for ELISA are proposed.

Un quinquenio de experiencia (2005-2010) con infecciones por Salmonella spp en un centro nacional de referencia en pediatría / A five-year experience with zoonotic Salmonella at a pediatric reference centre

Resumen Introducción: Salmonella sp puede causar infecciones asintomáticas, gastroenteritis, bacteriemia e infecciones focales como meningitis y osteomielitis. Objetivo: Describir aspectos microbiológicos y clínicos de las infecciones por Salmonella spp en niños en un hospital de referencia pediátrico Centro Hospitalario Pereira Rossell. Montevideo Uruguay. Material y Métodos: Estudio descriptivo y retrospectivo de pacientes en quienes se aislara Salmonella spp en el período 1 de enero de 2005 al 31 de diciembre de 2010. Resultados: Se aisló Salmonella spp en 46 niños menores de 15 años. Dieciocho eran menores de 2 años y 5 niños menores de tres meses. 24% de los pacientes presentaba factores de riesgo (infección por VIH; enfermedad hemato-oncológica, desnutrición) y co-morbilidades (bajo peso al nacer y neumonía). No hubo fallecidos. Los serotipos más frecuentes fueron: Typhimurium y Enteritidis. La mayoría de las cepas eran sensibles a ampicilina y cefalosporinas de tercera generación. Discusión: La presentación clínica predominante fue diarrea con sangre, no se presentaron brotes. Basados en los perfiles de susceptibilidad antimicrobiana, se pueden mantener las recomendaciones hasta el momento sugeridas. Conclusiones: Se debe tener en cuenta la infección por Salmonella sp en niños febriles con riesgo de enfermedad bacteriana invasora, con o sin focalidad.

Background: Salmonella can cause asymptomatic infections, diarrhea, bacteremia and focal infections such as meningitis and osteomyelitis. Aim: To describe clinical and microbiological aspects of infections by Salmonella spp. in children in a pediatric referral hospital: Centro Hospitalario Pereira Rossell, in Montevideo, Uruguay. Materials and Methods: Descriptive and retrospective study of 46 patients, from which Salmonella spp was isolated between January 1, 2005 and December 31, 2010. Results: Salmonella spp was isolated in 46 children younger than 15 years old. 18 were below 2 years old and 5 children below three months. 24% of the children had risk factors, such as HIV infection, oncological diseases and malnutrition; low birth weight and pneumonia were associated conditions. No deaths were reported. The serotypes more frequently found were: Typhimurium and Enteritidis. Most of the strains were susceptible to ampicillin and third generation of cephalosporins. Discussion: Diarrhea with blood was the predominant clinical presentation, and there were no outbreaks. Typhimurium and Enteritidis were the most common serotypes. Based on the profiles of susceptibility antimicrobial, we could maintain the same recommendations until the moment suggested. Conclusions: we must consider the Salmonella infection in febrile children under risk of an invasive bacterial disease, with or without focal infection.

Etiología y evolución de las infecciones osteo-articulares 2009-2015: Hospital Pediátrico del Centro Hospitalario Pereira Rossell, Uruguay / Etiology and evolution of the osteoarticular infections. 2009-2015: Pediatric Hospital Pereira Rossell Uruguay

Background: The most frequent osteoarticular infections (OAI) etiological agent is Staphylococcus aureus. The prevalence of other microorganisms has changed after the introduction of new vaccines. Aim: To describe the etiology and evolution of the OAIs in children hospitalized in Pediatric Hospital Pereira Rossell between 2009 and 2015. Patients and Methods: Joint fluid and bone puncture studies of hospitalized children suspected of OAI. Epidemiological characteristics, isolated microorganisms, complementary tests, initial treatment, complications, and days of hospitalization were analyzed. Results: 335 patients; the etiology was established in 113. Clinical data could be analyzed in 87 cases. The average age was 6.1 years. They corresponded to: methicillin-sensitive S. aureus (n: 47), community-acquired methicillin-resistant S. aureus (CA-MRSA) (n: 11), Streptococcus pyogenes (n: 6), Streptococcus pneumoniae (n: 1), Haemophilus influenzae type b (n: 2), Gram-negative bacilli (n: 9), Kingella kingae (n: 1) others (n: 6). In 4 cases, more than one microorganism was isolated. CA-MRSA infections were more serious. Discussion: A decrease is observed in the number of CA-MRSA isolates. A fact to be highlighted is the impact of universal vaccination against S. pneumoniae and H. influenzae type b. It is a finding to be monitored the increasing number of Gram-negative bacilli isolates.

Introducción: El agente etiológico más frecuente de las infecciones osteoarticulares (IOA) es Staphylococcus aureus. Luego de la introducción de nuevas vacunas la prevalencia de otros microorganismos ha cambiado. Objetivo: Describir la etiología y evolución de las IOA en niños internados en el Hospital Pediátrico del Centro Hospitalario Pereira Rossell entre los años 2009 y 2015. Pacientes y Métodos: Se identificaron los cultivos de muestras de líquido articular y punción ósea de niños con sospecha de IOA. Se analizaron sus características epidemiológicas, microorganismos aislados, exámenes complementarios, tratamiento inicial, complicaciones y días de hospitalización. Resultados: Se estudiaron 335 pacientes, se aisló microorganismo en 113. Se analizó 87 casos. Edad media 6,1 años. Correspondieron a S. aureus sensible a meticilina (n: 47), S. aureus resistente a meticilina adquirido en la comunidad (SARM-AC) (n: 11), Streptococcus pyogenes (n: 6), Streptococcus pneumoniae (n: 1), Haemophilus influenzae tipo b (n: 2), bacilos gramnegativos (n: 9): Kingella kingae (n: 1), otros (n: 6). En 4 casos se aisló más de un microorganismo. Las infecciones por SARM-AC fueron más graves. Discusión: Se observa un descenso de aislados de SARM-AC. Se destaca el impacto de la vacunación universal contra S. pneumoniae y H. influenzae tipo b. Se debe vigilar el aumento de aislamiento de bacilos gramnegativos.

Enfermedades invasoras por Streptococcus pyogenes 2005-2013: Hospital Pediátrico del Centro Hospitalario Pereira Rossell, Uruguay / Invasive Streptococcus pyogenes diseases 2005-2013: Pediatric Hospital Pereira Rossell Uruguay

Introduction: Streptococcus pyogenes infection causes a wide spectrum of clinical manifestations. Invasive disease (ID) is defined by the isolation of the microorganism from sterile sites. Objective: To analyze the clinical, epidemiological and molecular characteristics of ID by S.pyogenes in children hospitalized at Pediatric Hospital Pereira Rossell, from January 2005 to January 2013. Materials and Methods: A descriptive retrospective study was done in cases with isolation of S.pyogenes from sterile sites. Epidemiological variables, disease characteristics, laboratory parameters, treatment regimen received, hospitalization days and clinical outcome were analyzed. The presence of 4 genes encoding for virulence factors and chromosome profile studied by pulsed-field electrophoresis were done in the isolated strains. Results: A total of 42 cases (rate: 4.6 out of 10,000 admissions) were detected, from which 32 were analyzed. Average age was 44.7 months (14/32 < 2 years of age). In 5 cases, the portal of entry was identified. Clinical presentations were: osteoarticular infections (n = 15), shock (n = 6), skin and soft-tissue infections (n = 5), pneumonia (n = 3) and bacteremias (n = 3). Twenty cases required surgical procedures and 13 required intensive care admission. Average hospital stay was 17 days and one patient died. Molecular studies were performed in five strains; 4 different toxin profiles and pulsotypes were identified. Discussion: The incidence of ID at our hospital is similar to other series in the region. A better knowledge of clinical presentation and its relation with molecular characteristics represents a challenge.

Introducción: Streptococcus pyogenes, produce diversas manifestaciones clínicas. La enfermedad invasora (EI) se define por el aislamiento del microorganismo en sitios estériles. Objetivo: Analizar características clínico-epidemiológicas y moleculares de EI por S. pyogenes en niños hospitalizados en el HP-CHPR (1/1/05-31/1/13). Materiales y Métodos: Estudio descriptivo, retrospectivo, de casos con aislamiento de S. pyogenes de sitios estériles. Se analizaron variables epidemiológicas, características de la enfermedad, laboratorio, tratamientos, días de hospitalización y evolución. Se estudió la presencia de cuatro genes que codifican factores de virulencia y perfiles cromosómicos resueltos por electroforesis en campos pulsados. Resultados: Se detectó un total de 42 casos (tasa 4,6 cada 10.000 admisiones), se analizaron todas las variables en 32. Mediana de edad 44,7 meses (14 < 2 años). En cinco se identificó puerta de entrada. Formas de presentación: infección osteo-articular (n: 15), shock (n: 6), infección de piel y tejidos blandos (n: 5), neumonía (n: 3) y bacteriemia (n: 3). Veinte requirieron procedimientos quirúrgicos y 13 de cuidado intensivo. La media de estadía hospitalaria fue de 17 días. Hubo un fallecimiento. Se realizó estudios moleculares en cinco cepas, identificándose cuatro perfiles de toxinas y pulsotipos diferentes. Discusión: La incidencia de EI en nuestra institución coincide con otras series en la región. Profundizar el conocimiento de la presentación clínica y su relación con las características moleculares es un desafío.

Safety and immunogenicity of a paediatric presentation of an influenza vaccine.

BACKGROUND: Flu vaccination in otherwise healthy infants and young children is important to prevent severe disease, as well as to control epidemic spread of influenza infection. AIMS: To examine the safety and immunogenicity of a paediatric presentation of a purified, inactivated, triton split influenza vaccine. METHODS: Two doses of the vaccine, provided in prefilled syringes of 0.25 ml, were administered, one month apart, to 67 children under 3 years of age. RESULTS: Nine cases of immediate reaction to vaccination (macules/papules) were observed after the second injection only. During the study period, 9% of children experienced at least one delayed local reaction, and 28% of children presented at least one systemic reaction. Almost all reactions were mild and transient. Immunogenicity results surpassed the European Community recommendations for a 0.50 ml dose of vaccine in adults. CONCLUSION: This paediatric formulation of inactivated flu vaccine appears safe and immunogenic in children from 6 months to 3 years of age; the convenient presentation in a prefilled syringe of 0.25 ml volume will facilitate administration of the dose recommended for young children.

Etiology of children's diarrhea in Montevideo, Uruguay: associated pathogens and unusual isolates.

We studied microorganisms associated with infant diarrhea in a group of 256 children admitted to a public pediatric hospital in Montevideo, Uruguay. Diagnostic procedures were updated to optimize detection of potential pathogens, which were found in 63.8% of cases, and to be able to define their characteristics down to molecular or antigenic type. Coinfection with two or more agents was detected in more than one-third of positive studies. Escherichia coli enteric virotypes, especially enteropathogenic E. coli (EPEC), were shown to be prevalent. Rotavirus, Cryptosporidium, Campylobacter (mainly Campylobacter jejuni), and Shigella flexneri were also often identified. Enterotoxigenic E. coli, Salmonella, and Giardia lamblia were sporadically recognized. Unusual findings included two enteroinvasive E. coli strains, one Shigella dysenteriae 2 isolate, and a non-O:1 Vibrio cholerae culture. EPEC bacteria and S. flexneri (but not Salmonella) showed unusually frequent antimicrobial resistance, especially towards beta-lactam antibiotics, which is the subject of ongoing work.

Vigilancia del uso de antibióticos en el Hospital Pediátrico del Centro Hospitalario Pereira Rossell: susceptibilidad antimicrobiana; gasto y consumo de antibióticos / Vigilance of antibiotic use in a pediatric hospital (Hospital Pediátrico del Centro Hospitalario Pereira Rossell): antimicrobial susceptibility; cost and consumption antibiotics

Introducción: el uso de guías para el tratamiento antibiótico empírico constituye una estrategia fundamental para contener el aumento sostenido en la resistencia bacteriana y en los gastos en antibióticos. En 1998, en el Hospital Pediátrico del Centro Hospitalario Pereira Rossell se adecuaron las guías de antibioticoterapia empírica par alas infecciones más frecuentes asistidas en salas generales y en emergencia, en base a la epidemiología local. Desde esa fecha se comenzó la vigilancia deel uso de antibióticos. Objetivos: analizar los resultados de esta vigilancia sobre el gasto y el consumo de antibióticos y sobre la susceptibilidad antimicrobiana. Metodología: se determinó el gasto generado por los antibióticos recomendados en las guías de atención hospitalaria, en salas generales y en emergencia (penicilina, aminopenicilinas, cefalosporinas, macrólidos). Para estimar el consumo en pacientes hospitalizados se calculó la dosis diaria definida (DDD)/100 camas día para cada uno de los antibióticos. Se compararon los resultados de gasto y consumo 2001-2. Se comparó la susceptibilidad antimicrobiana de los gérmenes más frecuentes del período 2001-2 con la previa a la adecuación de las guías terapéuticas. Resultados: los antibióticos recomendados representaron enel año 2001, 57 por ciento del gasto en antibióticos (2.206.652,57 pesos) y en 2002, 54 por ciento (1.441.280 pesos). Los antibióticos más usados fueron las animopenicilinas. El consumo de cefuroxime intravenoso disminuyó 60 por ciento (de 13.1 a 5.36 DDD/100 camas-día). El consumo de ceftriaxona intravenosa y de amoxicilina oral aumentó 38 por ciento y 16 por ciento, respectivamente. Para el resto de los antibióticos el consumo se mantuvo constante. Las tasas de susceptibilidad antimicrobiana de los gérmenes más frecuentes (S. pneumoniae, S. aureus, E, coli, Shigella spp) a los antibióticos recomendados en las guías terapéuticas se mantuvieron por encima de 80 por ciento. Conclusiones: estos son los primeros resultados de la vigilancia del uso ded antibióticos en este hospital y demuestran la vigencia y la aceptación de las guías de antibióticoterapia empírica propuestas. Es difícil interpretar la disminución del gasto en antibióticos debido a la variación en el precio de estos medicamentos en este período.